Infections

Measles: An Old Bad Disease Returns

JOHN G. SCOTT

FEB 28, 2026

Epidemiology of Measles

Measles is the world’s most infectious disease. It has a basic reproductive number (R₀) of 12-18. That means that each infected person infects 12-18 other non immune people. As a result, 90% of susceptible people will get measles from exposure to 1 person with measles. The measles virus can linger in the air for 2 hours after a person with measles has left a room. Any susceptible person who enters that room during the 2 hour time period can be infected with measles. Here is a picture of a child with a typical measles rash.

Most US doctors have never seen a case of measles like this child. That, unfortunately is about to change.

For comparison of infectivity let’s look at the R₀ for other diseases we consider very contagious. R₀ for Ebola is 1.5-2.5, R₀ for COVID is 2.2-3.6 and R₀ for influenza is 1.2-1.4. As you can see none of these diseases comes even close to being as infectious as measles.

There are only two other diseases that are closer to being as contagious as measles. The R₀ for pertussis (whooping cough) is 5-17 (see my recent post on pertussis). The R₀ for varicella (chicken pox) is 10-12.

History of Measles in the US Prior to Measles Vaccine

Prior to the introduction of the measles vaccine in 1963, virtually all children in the US had measles by age 15. Having measles (and surviving it) provides lifetime immunity to measles, so adults born before 1954 have had measles and are already immune. People born before 1954 do not need to be vaccinated for measles.

Symptoms of Measles

Here is a description of measles symptoms from the Mayo Clinic

“Measles symptoms show up around 7 to 14 days after contact with the virus.

The first symptoms usually are:

  • Fever, which may be as high as 105 degrees Fahrenheit (40.6 degrees Celsius).
  • Dry cough.
  • Runny nose.
  • Red, watering eyes, called conjunctivitis.

About 2 to 3 days after the first symptoms, you also may see tiny white spots inside the mouth, called Koplik spots.

About 3 to 5 days after symptoms first start, or about 14 days after you come into contact with the virus, it’s common to see a rash. The rash is made up of large, flat spots and small raised bumps. The rash starts on the face or neck and spreads down the body from the chest to the arms and legs. A person with measles can spread the virus four days before the rash appears and four days after.”

Measles is obviously not a pleasant disease to have. Fever of 104-105 is pretty scary. All children with measles are miserable, but most children without complications recover from measles in about 10 days.

Complications of Measles

This information comes from the CDC.

Ear Infections

1 in 10 children with measles get bacterial ear infections that may need antibiotics

Hospitalization

About one in 5 children and adults with measles have to be hospitalized,

Pneumonia 

One out of every 20 children with measles gets measles pneumonia. pneumonia is the most common cause of death from measles in children.

Encephalitis

One child out of every 1000 will develop encephalitis (inflammation of the brain). This condition can also cause death, but children who survive may have deafness and/or intellectual disability.

Death

Three children out of every 1000 children with measles will die from their disease, either from respiratory or neurological complications.

Subacute Sclerosing Pan Encephalitis (SSPE)

This is a uniformly fatal brain disease that can occur 7-10 years after a measles infection. Fortunately it is rare, but children who get measles before age 2 are at higher risk of SSPE.

Herd Immunity to Measles

The recommended regimen for MMR (measles, mumps and rubella) vaccination that gives the most protection is to be vaccinated at age 1 year and a second dose at age 4-5. This regimen gives lifelong 97% protection against contracting measles. This means that children under 1 year of age are protected only by everyone around them being immune to measles. Measles is a live vaccine (a weakened strain of the measles virus). People who have weakened immune systems because of chemotherapy or other causes of immune deficiency cannot receive live virus vaccines. Their only protection from measles is herd immunity. Herd immunity means that enough people are vaccinated or immune that a susceptible person who cannot be vaccinated is protected by the “herd” of people who are vaccinated.

Measles is so contagious that 95% vaccination rate is necessary to prevent measles entirely. Outbreaks start to occur if vaccination rates fall below 95%. Large outbreaks occur at vaccination rates below 90%.

In 2025 MMR vaccination rates ranged from a low of 75% in Idaho to 98% in Connecticut. Only 10 states had MMR vaccination rates above 95%.

MMR Side Effects

There are occasional side effects to MMR vaccine but the vast majority of those are mild. They include pain and swelling at the injection site, fever, a mild rash about 10 days after vaccination and some joint stiffness. When they happen these side effects disappear completely in a day or two. There are some very rare more serious reactions including febrile seizures (8 in 10,000 vaccinations), bruising or bleeding from low blood platelets (1 in 20,000 vaccinations) and severe allergic reactions (1 in 1 million vaccinations. Febrile seizure is scary for parents but does not recur and has no long term effects on the child. The other rare side effects are manageable. There are no known deaths from side effects of MMR vaccine. It is also important to point out that all of these side effects are much more common with measles infections.

MMR Vaccination Resistance 

Worry about side effects of MMR vaccine has led to parents refusing MMR for their children. The main reason for vaccination resistance is worry that MMR vaccine causes autism. Very large well designed research studies have shown definitively that there is no connection between MMR vaccine and autism. The misinformation about MMR vaccine and autism unfortunately persists. This vaccination resistance has decreased the vaccination rate below the 90% threshold for serious outbreaks of measles in large parts of the US.

Current Outbreaks of Measles

I think the best way to show the resurgence of measles in the US is graphically. Below is a graph from the Johns Hopkins Bloomberg School of Public Health.

As you can see from this graph, measles cases started to rise after 2019 and went through the roof in 2025. 2026 is on track to have even more cases than 2025.

Deaths from Measles

Worldwide in 2025 95,000 children died from measles almost entirely from lack of measles vaccination. Three of those deaths were in the US. Given the resurgence of measles outbreaks across the US, we will undoubtedly see more deaths from measles.

Bottom Line

Measles is the most contagious disease in the world. Most children recover, but complications occur in 20% (one in five) children with measles. Complications include ear infections, hospitalizations, pneumonia, encephalitis and death. Vaccination rates must be at least 95% for complete herd immunity. Once vaccination rates fall below 90% large outbreaks of measles occur Vaccination rates are below 90% for large parts of the country and large outbreaks continue to occur in those communities with low vaccination rates. Measles is back with a vengeance!

Pertussis (Whooping Cough): Resurgence of a Deadly Disease

A recent article in the journal Pediatrics reported a surge in cases of pertussis, commonly known as whooping cough. Unfortunately the article is only available to subscribers to the journal. Here is a link to a description of that article in a medical news service called Medscape. Pertussis is a bad disease. See below.

History of pertussis

Pertussis is caused by a bacterium, Bordatella Pertussis. Prior to the advent of pertussis vaccines, pertussis was one of the leading US causes of death of children under 5 years of age. There were over 200,00 cases and 9000 childhood deaths in the US from pertussis every year (a rate of 4.5 deaths per thousand children). Pertussis was especially lethal in infants, and was probably the leading cause of death in this age group. Worldwide, pertussis prior to vaccines was just as bad as in the US or worse. Worldwide there were 24.1 million cases and 160,700 deaths in children under five every year.

Epidemiology of pertussis

In un-immunized people pertussis is extremely infectious, almost as much as measles. One infected person on average infects 12-18 other people. In adolescents and adults pertussis is unlikely to cause death or hospitalization, but it is an extremely unpleasant disease. Older children and adults have paroxysms of coughing, followed by a loud, wheezing inspiration (the whoop of whooping cough). These symptoms can last for weeks or months. The coughing is sometimes so severe that people break ribs or develop hernias. Treatment with antibiotics is used to prevent transmission. Antibiotics are also given to contacts to prevent them from getting infected. Antibiotics do not have any effect on the length or severity of the disease. Those who have symptomatic pertussis just have to wait for it to go away. Here is an audio file of a child with pertussis. You should listen to it realize what a severe disease pertussis is. Let me warn you that it is distressing to listen to.

Pertussis vaccines

Whole cell pertussis vaccines

Whole cell pertussis vaccine combined with vaccines for tetanus and diphtheria was widely introduced and given to infants and children in the 1940’s. This was a highly effective vaccine. It not only prevented disease, but also prevented colonization and therefore stopped transmission of pertussis. It reduced the cases of pertussis by 75%. Unfortunately, the whole cell vaccine had rare but concerning side effects.These iincluded persistent crying, febrile seizures and hypotonic-hypoeresponive episodes (HHE). Children with HHE had sudden onset of reduced muscle tone, decreased responsiveness to verbal or other stimuli, and change in skin color (pallor or cyanosis) that occurred shortly after vaccination. These adverse events, though temporary were obviously distressing to parents. There were also rare cases of encephalopathy (Inflammation of the brain) that caused permanent disability. These cases were so rare that it was impossible to know whether these permanent disabilities were caused by the vaccine, or were simply associated but not causal. Controversy over whether the vaccine had any role in these cases continues even today.

Acellular pertussis vaccine

Because of the rare but distressing side effects of whole cell pertussis vaccine, a new vaccine was developed that had components of the pertussis bacterium, but not whole cells. This was called the acellular vaccine. This acellular vaccine had far fewer and milder adverse reactions than the whole cell vaccine. The combination vaccine is abbreviated DTaP (diptheria-tetanus-acellular pertussis). This is the vaccine used for children today. Unfortunately the acellular pertussis vaccine is less effective than the previous whole cell vaccine. It does prevent children from getting ill with pertussis, but it does not prevent colonization of the nose and throat. Children who are colonized in this way are not sick, but they are infectious and can pass on the virus to other children and adults. This keeps the bordatella pertussis bacteria circulating in communities.

Waning Immunity

Neither the whole cell nor the acellular vaccine provides lifetime immunity, unlike the Measles-Mumps-Rubella vaccines, which do provide lifetime immunity. Even people who have pertussis do not get lifetime immunity. Immunity from vaccines and infection wane over time. It appears that the acellular pertussis vaccine gives good protection from getting sick from pertussis for about 4 years, and starts to wane after that. The result is that we still see pertussis even in fully immunized children and adults starting about 5 years after the last routine immunization, which occurs at between 4 and 6 years of age. A booster TDaP is also recommended at around 12 years of age. This means that the most vulnerable children, that is children 5 or under are protected from getting ill from pertussis. Infants below 2 months of age (too early for vaccination) are protected by the recommendation that all pregnant women get a booster TDaP vaccine in the third trimester of every pregnancy. Anyone who is going to have extended contact with an infant under 2 months should also get a booster TDaP.

Risk of resurgence of severe pertussis

Bordatella pertussis continues to circulate in communities because of colonization of immunized children. Resistance to vaccinating children with DTap can quickly cause a resurgence of pertussis in infants and young children. This would be disastrous and is already happening. In 2024, there were 35,435 documented cases of pertussis across the U.S., including 655 in Colorado. That was a huge jump over the 7063 cases in all of 2023. Large states, including New York and California, logged high numbers of pertussis infections in 2024. So did some less-populated states like Idaho, Washington and Oregon, each of which reported more than 1,000 cases of pertussis. There were 10 deaths from pertussis in 2024. Cases are on track to be even higher in 2025.

Research on new pertussis vaccines

The search is on for a new pertussis vaccine that prevents colonization but that also does not cause the distressing side effects that happened with the whole cell pertussis vaccine. The best candidate at the moment is a live vaccine that has been genetically modified to eliminate the toxins produced by the bacterium. If and when approved this vaccine will be administered nasally. In rhesus monkeys it prevented colonization with bordatella pertussis and had no significant side effects. It is currently in phase 3 trials in humans.

Bottom Line

Pertussis is a serious disease and is life threatening to infants and young children. The severity and duration of pertussis are not affected by antibiotics that are given to limit the spread of the disease. The only effective treatment of pertussis is prevention through immunization. Acellular pertussis vaccine is much safer but also less effective than the old whole cell vaccine. It allows bordatella pertussis to continue to circulate in communities. Resistance to immunization of children has led to a marked increase in serious pertussis infections in 2024 with 10 deaths reported. Pertussis cases are on track to be even higher in 2025. A promising new attenuated live pertussis vaccine is in phase 3 trials and may soon be approved assuming research funding is not withheld by the Trump administration.

mRNA Vaccines – Truth vs Misinformation

Robert F Kennedy Jr has stopped funding for research to develop new mRNA vaccines because he says they don’t work well for respiratory diseases. He also claims that mRNA vaccines induce mutations in respiratory viruses. He says that even one mutation makes mRNA vaccines ineffective. Here is a link to his video post on X where he makes these claims. He also claims that he has consulted science experts who agree with him about mRNA vaccines.

In this post I will review the real science about mRNA vaccine technology, how mRNA vaccines differ from traditional vaccine technology and also discuss how viruses mutate and why (spoiler alert: they don’t mutate because of mRNA vaccines). Here is a link to a STAT news article that deconstructs Kennedy’s arguments: Kennedy’s case against mRNA vaccines collapses under his own evidence.

Traditional vaccines

There are two types of traditional vaccines, live vaccines and killed vaccines. Both types require growing the target virus in tissue culture. In a live vaccine, the virus is weakened so that infection does not cause the disease when injected into people with healthy immune systems. The MMR vaccine is an example of a live vaccine. It contains weakened strains of measles virus, mumps virus and rubella virus. Killed vaccines use some proteins from the virus to sensitize the immune system to kill the virus when it detects those proteins. the DPT vaccine is an example of a killed vaccine. It contains protein fragments from the diphtheria virus, pertussis (whooping cough) virus and tetanus virus. It is very labor intensive to create a vaccine using these traditional methods. To make enough weakened virus or virus protein fragments to immunize a large population takes a lot of tissue culture and a long time. It usually takes 10-15 years of research and development before new traditional vaccines are ready to use. Manufacturing those already approved vaccines is still very labor intensive.

What is mRNA?

The m in mRNA stands for messenger RNA. The genes in your DNA can’t do anything by themselves. They don’t directly make proteins. Instead they code for messenger RNA. Messenger RNA does the work of making proteins that determine hair color, eye color and all other genetic traits. Each type of messenger RNA is specific for a particular protein. Messenger RNA does not last very long in animal (or human) cells. It lasts from a few minutes to a few hours and then it disappears. The DNA makes more messenger RNA as needed.

How does an mRNA vaccine work?

The advantage of an mRNA vaccine is that the body does all the work of manufacturing the virus protein fragment. No intensive tissue culture is required. mRNA is synthesized in a laboratory. The synthesized mRNA codes for a specific virus protein. In the case of the COVID mRNA vaccine, the mRNA codes for the spike protein. When that mRNA is injected into a muscle, the muscle cells start to make many copies of the spike protein. The immune system recognizes this as a foreign protein and makes antibodies against it as well as sensitizing killer lymphocytes so that they recognize the protein too. Just like the body’s own mRNA, the injected mRNA only lasts for a few minutes to a few hours and then disappears. It never changes the DNA in the cell, because DNA makes mRNA, not the other way around.

How does mRNA vaccine speed up the vaccine development process?

We now have the technology to rapidly determine all the genetic code of a new virus. That sequencing can happen within a few weeks of discovering a new virus. That genetic code allows us to determine which proteins make up the virus particle. We can then decide which viral protein is the best to stimulate immunity to the virus and synthesize an mRNA molecule that will make that protein in human muscle cells. That process is much faster than the traditional method. We had an effective mRNA COVID vaccine within a year of the beginning of the pandemic. That is an absolutely unprecedented time scale in new vaccine development.

Do mRNA vaccines induce mutation in viruses

This is what Kennedy claims and it is absolutely not true. Some viruses, like COVID and flu virus mutate frequently and some like measles virus and polio virus are stable and do not mutate or mutate rarely.. The mutation rate depends on the nature of the virus, not on the vaccine. All vaccines, not just mRNA vaccines for viruses that mutate frequently lose some efficacy over time and the vaccine has to be modified. The viruses that mutate frequently would continue to do that whether a vaccine is available or not. Vaccines do not make viruses mutate faster. Most mutations make the virus less infectious, but the occasional mutation makes the virus more infective. The mutations that are more infective become more frequent and crowd out the older versions of the virus. Measles and polio vaccines prevent infection because the measles and polio viruses stay exactly the same over time.

Safety of mRNA vaccines

The only mRNA vaccine that we have extensive experience with are the ones developed for COVID. Mild reactions were common (sore arm, fever. myalgias) more commonly with the second dose. Rare cases of myocarditis (inflammation of the heart muscle) were reported in younger people. All of these were transient and completely resolved. There is a very tiny chance of having a severe allergic reaction to the vaccine. Out of 8 billion doses administered death due to allergic reaction occurred in 14 people. That is a risk of death of 1.75 x10-9 (1.75 preceded by 9 zeros!).That risk is much, much smaller than the risk of being killed in an auto accident. The risk of death from COVID in unvaccinated people is of course much higher. mRNA vaccines are safe with a minuscule risk of severe side effects.

Why do people still get influenza or COVID even after they have been vaccinated.

Antibodies induced by flu and COVID vaccines are in the blood stream and not as much on the mucus membranes. Although vaccinated people are less likely to get infected with influenza or COVID, the protection rate from infection is less than 100%. Vaccinated people can still get infected with influenza or COVID. The vaccine induced antibodies immediately start fighting the infection. This means that vaccinated people who get infected are much less likely to get severe infections, much less likely to be hospitalized and are much more likely to have mild symptoms. You get a great deal of protection from the vaccine even if you get infected with the virus. Kennedy asserts that if you get infected with the virus, then the vaccine does not work. That is poppycock!

Research into new mRNA vaccines

Researchers can now use AI to develop universal mRNA vaccines for COVID and influenza that could develop immunity to multiple genetic variants at the same time. This technology would mean that new vaccines don’t have to be developed every year to deal with new genetic variants. This technology also might make it possible to develop vaccines for malaria and leptospirosis. It may also be possible to use this technology to develop vaccines that sensitize the immune system to destroy cancer cells.

All of the federal funding for research using this promising technology has been blocked by HHS secretary Robert F Kennedy Jr.

Bottom Line

mRNA vaccines can be developed much faster than traditional vaccines. They are safe and effective at both preventing disease and making disease much milder when infection does occur. mRNA technology has the potential to make universal flu and COVID vaccines, vaccines for malaria and leptospirosis and even vaccines to prevent cancer. It is unconscionable that federal funding for this important research has been halted.

Measles

Measles (also called rubeola) is one of the most infectious diseases in the world. Infectiousness of a disease is measured by something called R0 (basic reproduction number). This is a measure of how many people will be infected by one person with the disease in an un-immunized population. For measles R0 ranges from 12-18. That means in an un-immunized population, 1 person with measles will on average infect 12 or more others. To put this in perspective The R0 for influenza is 0.9-2.1. The R0 for Ebola is 1.9. The R0 of COVID19 is 1.4-2.4. You can see that the infectivity of the measles virus is as much as ten times higher than other diseases that we consider very infectious.

Measles Vaccine

The recommended two doses of measles vaccine offers lifetime 97% protection against being infected with measles. The measles vaccine is a live vaccine. This means that it is a form of measles virus that has been weakened (attenuated) so that it will not cause infection in people with normal immune systems. It cannot be given, however to people with weak immune systems, such as people on chemotherapy for cancer. It also cannot be given to infants younger than 6 months because their immune systems are not developed enough for a live virus vaccine. 1 dose of MMR vaccine can be given to infants at least 6 months old if they are going to travel to a country where measles is still endemic. This offers some protection, but they still need two doses of the MMR vaccine after age 1. The recommended age for the first dose of the measles vaccine is 1 year. The second dose is usually given at age 5 or 6. Even the first dose gives 93% protection against being infected with measles.

People who cannot get the measles vaccine are protected by all those people who do get the vaccine. This is called herd immunity. If enough of the population has been vaccinated then there is no transmission of measles even to those people who can’t take the vaccine. Outbreaks of measles are unlikely to happen if at least 90% of the population has been vaccinated. The lower the vaccination rate below 90%, the more likely measles outbreaks will occur in unvaccinated people. In Gaines county, Texas, where the current measles outbreak started, the measles vaccination rate was 75%.

Is the measles vaccine safe?

The measles vaccine is given in combination with mumps and rubella (German measles) vaccines. Reactions are not common but some children get a sore arm and/or a mild fever. One in three thousand children will have a febrile seizure. Although a febrile seizure is very scary for parents, a febrile seizure is not life threatening and never happens again unless the child already has an underlying seizure disorder. An even smaller number of children have an allergic reaction to the MMR vaccine. An allergic reaction is a rare complication of any vaccine. About one in 40,000 children can get a low platelet count. This usually resolves on its own and rarely requires treatment.

How dangerous is measles?

Measles can cause pneumonia and encephalitis (inflammation of the brain) particularly in un-immunized children under 5. About one in five children (or adults) with measles have to be hospitalized. Up to two children per thousand cases die from complications of measles. There is a rare but always fatal inflammation of the brain that can occur up to 7 years after having had measles. It is called subacute sclerosing pan encephalitis (SSPE). When immunization rates in the US were above 90% SSPE disappeared. Unfortunately with the current US outbreaks we may see it again.

In the 10 years before the measles vaccine was available nearly all children got measles by the time they were 15 years old. It is estimated 3 to 4 million people in the United States were infected each year. Among reported measles cases each year, an estimated 175,000 developed pneumonia; 48,000 were hospitalized; 1,000 suffered encephalitis (swelling of the brain); 400 to 500 people died.

As of March 7 the current outbreak in Texas and New Mexico is up to 208 cases, 198 in Texas and 10 in New Mexico. Twenty-three children have been hospitalized. There have already been two deaths in this outbreak, one in Texas and one in New Mexico.

Recommendations

If you were born before 1957 then you have had measles and are already immune. You don’t need vaccination. If you were born after 1957 and you have never had measles vaccine, then you and your children (if they are also un-immunized) should go to your pharmacy or health department and get vaccinated immediately. The risk of measles infection is much much higher than the rare adverse effects of the MMR vaccine. If your child has already had two doses of MMR vaccine after age 1 then he/she does not need to be re-vaccinated.

From 1963 until 1967 an inactivated measles vaccine was used in the US. This vaccine did not give long lasting immunity. If you were vaccinated between those years, you should get at least one MMR booster. From 1963 to 1989 only on MMR vaccine was recommended. If you were vaccinated between those years you should get a booster MMR if you live in an area with a low vaccination rate or if you are planning international travel. After 1989 two vaccinations were recommended. If you were vaccinated after 1989 you don’t need a booster.

Treatment of Measles

Once a child gets measles, there is no treatment other than supportive therapy. There are no antiviral drugs that work against the measles. Virus. Robert F Kennedy Jr, unfortunately now head of HHS, has stated that getting measles vaccine is a personal decision. While that is technically true, nothing else prevents or treats measles. Kennedy has suggested that vitamin A and Cod liver oil can be used to treat measles. There is absolutely no evidence for this and furthermore too much vitamin A can be toxic.

Bottom Line

Measles can be a deadly disease, especially for children under 5. The MMR vaccine is safe and serious reactions are very rare. Two doses of measles vaccine after age 1 gives lifetime 97% immunity to measles. There is no anti-viral medicine that treats measles. Vitamin A and cod liver oil do not work and too much vitamin A can be toxic.

Antibiotics – When You Need Them and When You Don’t

In the era before antibiotics were available one third of all deaths were from infectious disease. The introduction of antibiotics starting with penicillin represented a tremendous advance in the treatment of infectious diseases. We soon learned, however that overuse of antibiotics led quickly to the development of bacteria that became resistant to that antibiotic. Penicillin, for example can only be used for a small number of infectious diseases now including strep infections and syphilis. In this post I will write about both individual and societal harms of overuse of antibiotics and will also discuss conditions for which they should be and should not be used.

Harms of Antibiotics

Bacterial Resistance

Overuse of antibiotics can lead quickly to resistance. Unfortunately, resistance has eventually developed to nearly all currently available antibiotics. Some bacteria, called gram negative bacteria have developed resistance to almost all antibiotics. Antibiotic resistance in the United States kills approximately 23,000 patients a year and incurs over $20 billion in additional medical expenses.

Overuse of antibiotics

The information below comes from an excellent paper from the journal Pharmacy and Therapeutics: The Antibiotic Resistance Crisis.

 in 2010, the last year that we have complete data, 22 doses of antibiotics were prescribed per person in the U.S. In many other countries, antibiotics are unregulated and available over the counter without a prescription. This lack of regulation results in antibiotics that are easily accessible, plentiful, and cheap, which promotes overuse.

Inappropriate Prescribing

Many studies have shown that antibiotic therapy is not necessary in 30% to 50% of cases! Even in intensive care units 30% to 60% of the antibiotics prescribed have been found to be unnecessary, inappropriate, or at inadequate doses.

Extensive Agricultural Use

In both the developed and developing world, antibiotics are widely used as growth supplements in livestock.  About 80% of antibiotics sold in the U.S. are used in animals, to promote growth and to prevent infection. Molecular detection methods have shown that resistant bacteria in farm animals reach consumers through meat products. This happens through the following sequence of events:

1) Antibiotic use in food-producing animals kills or suppresses susceptible bacteria, allowing antibiotic-resistant bacteria to thrive

2) Resistant bacteria are transmitted to humans through the food supply

3) These bacteria can cause infections in humans that are resistant to most antibiotics

Consequences of Antibiotic Resistant Infections

A 2011 national survey of infectious-disease specialists found that more than 60% of the infectious disease doctors had seen a pan-resistant, untreatable bacterial infection within the previous year. Many public health organizations have described the rapid emergence of resistant bacteria as a “crisis” or “nightmare scenario” that could have “catastrophic consequences.”

Antibiotic Effects on Human Microbiome

It is well established that the gut microbiome plays an important role in health.  It prevents disease causing bacterial colonization, regulates gut immunity, provides essential nutrients and metabolites, and is involved in control of energy. A healthy gut microbiome has lots of diversity. Broad‐spectrum antibiotics reduce gut bacterial diversity. While killing the disease causing bacteria of concern antibiotics can also kill beneficial bacteria.

Studies report changes in gut bacterial composition that last for up to 12 weeks after antibiotic treatment has ended with the incomplete restoration of bacterial composition and emergence of antibiotic‐resistant strains.  In one study one short term course of clindamycin (7 days) resulted in significant disturbances in the gut bacterial community that remained for up to 2 years post‐treatment!

When Antibiotics Are Not Necessary

Viral Infections

The vast majority of infections are caused by viruses. Antibiotics do nothing to shorten viral infections or to relieve symptoms. Here are some examples.

Upper respiratory infections

Symptoms are typical cold symptoms, including runny nose, nasal congestion, sore throat and cough. There may or may not be fever. Fever, sometimes high fever is more common in children. Green or brown discharge from the nose is common with viral upper respiratory infections and does not indicate bacterial infection. Viral upper respiratory infections usually last about 10 days, but can persist for several weeks.

Bronchitis

In otherwise healthy people, bronchitis is another example of a viral infection. The only exception to this is people with chronic obstructive lung disease, in which bronchitis may be caused by bacteria. The main symptom of bronchitis is cough, which may be dry or may be productive of sputum. Yellow or green sputum can occur and does not mean that the bronchitis is bacterial. There is usually no fever. Viral bronchitis can last for weeks. RSV virus can cause a severe bronchitis in children and older adults. There is a vaccine for children and adults that prevents RSV virus infections.

Sinusitis

Most sinus infections are viral and antibiotics are not helpful for these. Symptoms can include thick nasal discharge and some discomfort over the maxillary sinuses (underneath the eyes). Occasionally sinusitis can be bacterial and require antibiotics. I will discuss this later under conditions for which antibiotics are appropriate.

GI Viruses

There are other viruses that affect the gastrointestinal system. Symptoms are usually nausea and vomiting and/or diarrhea. Norovirus is the most common one. Staying hydrated is the only treatment for these viruses. Rotavirus affects children, but there is a an oral vaccine for infants that prevents this disease.

Ear Infections (Otitis Media)

Infections behind the ear drum are called otitis media. These occur almost exclusively in children and can be viral or bacterial. We used to treat all inner ear infections in children with antibiotics. We have now learned that most ear infections in children, even the bacterial kind get better without antibiotics. We now use antibiotics only for children with severe ear infections who more commonly have fever and/or severe pain.

When Antibiotics Should Be Used

Most bacterial infections require antibiotics to get better. It is not always possible for you to know whether you have a viral or bacterial infection. If you are concerned that you might have a bacterial infection you need to see your doctor who will decide whether you need antibiotics or not.

Strep Throat

Although many sore throats are viral, sore throat can also be caused by strep (streptococcus). Strep throat does not cause other symptoms like cough and runny nose. It is diagnosed by a rapid strep throat swab which your doctor can do in his/her office.

Bacterial Sinusitis

This usually happens after a viral upper respiratory infection. The most common sequence is that you start to feel better after a week or so and then get worse. Typically pain from bacterial sinusitis is one side, not both sides. The affected sinus becomes very tender to touch. Fever may or may not be present.

Infection in the ear canal (otitis externa)

This kind of infection is different from infections behind the ear. It can be painful and usually there is some pussy discharge from the ear. It usually responds to topical antibiotic ear drops, but when severe can require oral antibiotics

Pneumonia

Pneumonia can be viral, but it is not easy to tell that kind from the more serious bacterial pneumonia. All pneumonias should be treated with antibiotics. Symptoms of pneumonia are fever, sometimes high fever, cough (usually productive) and shortness of breath. A chest x-ray will show fluid in the air sacs in the lungs.

Urinary tract infection

Bladder infections are common, especially in women. The symptoms are frequent urination and pain or burning with urination. Your doctor will send a urine culture to make sure you are on the right antibiotic.

Kidney infections (also called pyelonephritis) are a more serious type of urinary tract infection. Symptoms can include fever, flank pain and feeling very ill. Sometimes kidney infections require getting IV antibiotics in the hospital.

Soft tissue infections (cellulitis)

A scrape or cut on the skin can sometimes get infected. Usually the area around the injury becomes red and painful. This kind of infection usually requires antibiotics. Again, this is a decision your doctor needs to make.

Sepsis

Sometimes a localized infection will spread through the blood stream and affect other organs. This is a medical emergency and requires hospitalization, IV antibiotics and fluids to maintain blood pressure.

Bottom Line

Overuse and inappropriate use of antibiotics has led to bacterial infections that are increasingly resistant to many and sometimes all antibiotics. Antibiotics, even when used appropriately lead to long standing adverse effects on the gut microbiome. The vast majority of infections are viral and do not improve with antibiotics. Bacterial infections do often require antibiotics. Decision about whether antibiotics are appropriate should be made by your doctor. Requesting antibiotics from your doctor can sometimes lead to inappropriate prescribing.

Bird Flu – What You Need to Know

Bird flu is a common name for avian influenza. Avian influenza has been around since the 1800’s and there have been sporadic outbreaks since then. The scientific name of the virus is AH5N1, but there are multiple subtypes of avian influenza virus and the virus continues to evolve over time. There have always been human cases, and some deaths but only related to contact with birds. The current avian influenza virus subtypes are extremely infectious to wild birds and poultry with a 60 to 100% mortality rate. Wild waterfowl, such as ducks and geese can spread the virus but usually do not get sick from it.

Infection in Cattle

In the last year avian influenza virus has mutated so that it has infected dairy cattle. Now there are several human cases in people who work with dairy cattle. Only about 10% of cattle with the virus have symptoms, but lactating cows are especially susceptible. There is evidence that cows can transmit the virus to other cattle. The virus has been found in raw milk, but not pasteurized milk. Drinking raw milk always has some risk of disease, but now that risk is much higher. There have been no human cases so far from drinking milk.

Infection in Other Mammals

Domestic cats are the most common other mammal that has been infected with A5HN1, but it has also been found in mink, foxes, raccoons, dogs, harbor seals, and most recently a dead polar bear. There have been no reported cases of human infection from contact with infected cats or dogs.

Potential for Human to Human Transmission

The AH5N1 virus has shown its potential to evolve rapidly, and this can happen in one animal. The influenza virus that caused the 1918 pandemic was an H1N1 virus that probably was initially a bird virus that mutated to infect humans. The current A5HN1 virus has shown no human to human transmission so far. The CDC currently rates the current public health risk of A5HN1 as low, but they are watching it carefully.

Human Symptoms of Avian Influenza

Most human cases have been mild, but severe illness and even death can occur.

Mild symptoms

  • eye redness and irritation (conjunctivitis)
  • mild fever (temperature of 100ºF [37.8ºC] or greater) or feeling feverish*,
  • cough
  • sore throat
  • runny or stuff nose
  • muscle or body aches
  • headaches
  • fatigue

Severe symptoms

  • high fever or other symptoms listed above that limit or prevent usual activity
  • shortness of breath or difficulty breathing
  • altered consciousness
  • seizures

Complications

  • pneumonia,
  • respiratory failure,
  • acute respiratory distress syndrome,
  • acute kidney injury
  • multi-organ failure (respiratory and kidney failure),
  • sepsis, septic shock
  • and inflammation of the brain (meningoencephalitis)

What you can do now to limit your risk

  • Do not touch or even get near dead birds
  • Do not drink raw milk
  • Keep cats inside and do not feed them raw milk or raw food
  • Stay away from any wild animals (raccoons, foxes) that appear ill
  • Keep up with current CDC bird flu recommendations at this website: Avian Influenza

Bottom Line

Avian influenza virus is able to mutate rapidly. In the last year it has become transmissible in dairy cattle. All human cases so far have been caused by contact with dead wild birds, poultry or dairy cattle. There has as yet been no human to human infection documented. The CDC reports that public health risk is currently low, but they are tracking animal and human cases carefully.

Mosquito Borne Diseases: Risks, Prevention & Treatment

Diseases carried by mosquitos have been in the news recently. Dr. Fauci had West Nile virus, which is carried by mosquitos. Some parks in Massachusetts have started an evening curfew because of cases of Eastern Equine Encephalitis, another mosquito borne disease. Mosquito borne diseases are rare in the US, but worldwide, mosquitos are the deadliest animal in the world. Worldwide, mosquito borne diseases kill 2.7 million people a year, 90% of which occur in Africa. As climate change causes increased global warming we are likely to see an increase in mosquito borne diseases in the US. In this post I will catalog all the mosquito borne diseases, which species of mosquitos carry them, and what areas have the most risk. Only a few species of mosquitos transmit diseases, but that information is primarily useful for epidemiologists and public health specialists. When a mosquito bites you, you are not going to know what species it is!

West Nile Virus

West Nile Virus is the most common disease transmitted by mosquitos, primarily by mosquitos of the culex species. Mosquitos get infected from birds and birds can get infected from infected mosquitos, so the disease passes back and forth between birds and mosquitos. People who get infected with West Nile cannot transmit it back to mosquitos that bite them.

Symptoms

Most people infected with West Nile virus do not have any symptoms but about 1 in 5 people who are infected develop a fever, headache, weakness, muscle pain, or joint pain, gastrointestinal symptoms and a transient rash. The illness usually lasts a few days, but can last for weeks. About 1 out of 150 infected people develop serious illness that invades the brain and spinal cord. This is called neuroinvasive illness. Sometimes this is fatal and if a person survives it they are likely to have permanent disability.

Species of mosquitos that carry it

Culex especially culex tarsalis

Treatment

There is no treatment or vaccine, so avoiding mosquito bites is the only way to keep from getting it when it has been identified in your area. I will write about the ways to avoid mosquito bites near the end of this post.

Who is at risk?

Cases are primarily in the summer and fall. Cases of West Nile disease have been reported across the continental United States. The CDC keeps track of human cases and cases identified in dead birds. West Nile virus occurs in epidemics in some years with few cases in others. So far in 2024 in the US there have been 289 cases of people with non-neuroinvasive West Nile illness and 189 cases of the serious neuroinvasive disease. Since 80% of infected people have no symptoms, that means the number of people with non-neuroinvasive infection so far this year is likely 5 x 289 = 1445. That is still a tiny percentage of the entire US population. Here is a link to the CDC web page showing 2024 West Nile cases by state and by county: West Nile Current Year Data (20240. If you live in an area where West Nile virus has has been identified in birds or humans, then you are at some increased risk.

Eastern Equine Encephalitis

The virus is maintained in fresh water hardwood swamps by birds and a particular species of mosquito called Culiseta melanura. This mosquito almost exclusively bites birds, so is not a significant risk to humans. The problem comes when infected birds are bitten by other species of mosquitos that do bite humans. Those species can infect humans.

Symptoms

Fortunately this is a rare disease. Thirty per cent of people infected with this virus die. Those who survive often have serious neurological problems. Symptoms are  fever, headache, vomiting, diarrhea, seizures, behavioral changes, and drowsiness.

Species that transmit the disease to humans

Aedes, Coquillettidia, and Culex

Treatment

There is no vaccine or treatment for Eastern Equine Encephalitis. Avoiding mosquito bites is the only prevention. More about how to avoid mosquito bites later in this post.

Who is at risk?

Most cases are in the Eastern US. There have been only 4 cases so far this year according to the CDC data, but there was a death from a case just in the last few days in New Hampshire. The states that have recorded cases so far this year are Vermont, Massachusetts, New Jersey, Wisconsin and now New Hampshire. People who live in the northeast may need to be especially careful this year.

Cache Valley Virus

This virus is named for the Cache Valley in Utah where it was first recorded. It is very rare. Less than 10 cases have ever been reported. It has been reported in Illinois, Michigan, Missouri, New York, North Carolina, and Wisconsin. It is a severe disease.

Symptoms

Symptoms include stiff neck, confusion, loss of coordination, difficulty speaking, or seizures.

Species that transmit the disease

The virus has been found in several species (Anopheles, Culiseta, Coquillettidia). The main species that transmits the disease is not known.

Treatment

There is no vaccine or treatment. Avoiding mosquito bites is the only prevention. More about how to avoid mosquito bites later in this post.

Who is at risk?

This disease is so rare that there is no particular region of the US that is at risk. Mosquitos carrying the Cache Valley virus have been found in many additional locations in North America and in parts of Central America.

Jamestown Canyon Virus

The virus is maintained by mosquitos biting infected animals, mostly deer. Mosquitos cannot transmit disease from biting infected humans, so humans are considered a “dead end” host.

Symptoms

This is another relatively rare disease, but more frequent than Cache Valley Virus. Most infected people do not have symptoms, but a few people get severe neuroinvasive disease. The CDC counts only the severe cases, so the number of cases substantially underestimate the number of people infected. There are about 23 severe cases reported a year, mostly in the spring through fall. Symptoms include fever, fatigue and headache. Some people have respiratory symptoms such as cough, sore throat or runny nose. Symptoms of severe disease can include stiff neck, confusion, loss of coordination, difficulty speaking, or seizures. Death is rare from this disease.

Species that transmit the disease

Aedes, Culex, Coquillettidia

Treatment

There is no vaccine or treatment. Avoiding mosquito bites is the only prevention.

Who is at risk

Jamestown virus is found through most of the US, but Minnesota and Wisconsin have reported more than half of the cases. Again, there is no vaccine or treatment. Prevention is again the best option.

LaCrosse Virus

La Crosse virus circulates in the environment between tree hole breeding mosquitoes and small mammals, such as chipmunks or squirrels.

Symptoms

Most infected people do not have symptoms, but the disease can be severe especially in children under 16 years of age. Initial symptoms can include fever (usually lasting 2-3 days), headache, nausea, vomiting, fatigue , and lethargy. Symptoms of severe disease include high fever, headache, neck stiffness, stupor, disorientation, coma, seizures, muscle weakness, vision loss, numbness, and paralysis. Most patients recover but death from LaCrosse virus happens rarely.

Species that transmit the disease

 Eastern tree hole mosquito (Aedes triseriatus). The tree hole mosquito is found almost exclusively in wooded or shady areas, and usually does not fly more than 200 yards from the area where it developed.

Treatment

There is no vaccine or treatment Avoiding mosquito bites is the only prevention.

Who is at risk?

Most cases occur in the upper Midwestern, mid-Atlantic, and southeastern states. LaCrosse virus is a rare disease. So far in 2024 there have been 13 cases of LaCrosse disease reported from Tennessee, North Carolina and South Carolina.

St Louis Encephalitis

St Louis Encephalitis virus circulates in the environment between mosquitos and birds.

Symptoms

Most infected people do not have symptoms. Severe disease usually occurs in older or immunocompromised people. Symptoms are fever, headache, dizziness, nausea, and generalized weakness. People with severe disease can develop stiff neck, confusion, disorientation, dizziness, tremors, and unsteadiness. 5-20% of infected people die from this disease. The risk of dying increases with age.

Species that transmit the infection

Culex

Treatment

There is no vaccine or treatment. Avoiding mosquito bites is the only prevention.

Who is at risk

In recent years sporadic cases and outbreaks have occurred in the Southwest. This is a rare disease and there have been no cases reported in 2024. In some years there are outbreaks primarily in urban areas. Again there is no vaccine or treatment for St Louis Encephalitis.

Dengue

Unlike many of the diseases discussed previously, Dengue virus circulates between humans and mosquitos. Mosquitos who bite infected people then spread the virus by biting other people. People can get Dengue multiple times.

Symptoms

Most infected people have no symptoms but 1 in 4 have symptoms which include Fever and bone and muscle pain. The pain can be severe. Dengue is also known as “break bone fever.” About 1 in 10 people who get sick have severe Dengue. Severe Dengue can result in shock, internal bleeding, and death. People with Dengue who have any of the following symptoms should go immediately to a hospital emergency department: belly pain or tenderness; vomiting; bleeding from the nose or gums; vomiting blood or blood in the stool.

Species that transmit the infection

Aedes.aegypti and Aedes.albopictus

Treatment

There is a vaccine for Dengue but it is only recommended for children who have already had one episode of Dengue. It is not available in the US. The only treatment is hospitalization and supportive care for severe illness.

Who is at risk?

Most Dengue in the US is in travelers from endemic areas. Endemic areas include the Caribbean, Central America, South America, Southeast Asia and the Pacific Islands. Many of these are popular tourist destinations, so the biggest risk for US citizens is travel to one of these regions. There have been some local outbreaks of Dengue in the US in Florida, Hawaii, Texas, Arizona, and California.

Treatment

Once again, other than the vaccine for children who have already had Dengue, treatment is supportive hospital care for people with severe Dengue. Travelers to endemic Dengue areas should use mosquito bite preventive measures, discussed further later in this post.

Chikungunya

Chikungunya virus, like Dengue, circulates in mosquitos and humans. Mosquitos become infected by biting a person with chikungunya virus and then spread the virus by biting other humans.

Symptoms

The most common symptoms are fever and joint pain and can include headache, muscle pain, joint swelling, or rash. Most patients feel better within a week, but joint pain can be severe and disabling and might persist for months. Death from chikungunya virus is rare.

Species that transmit the disease

Aedes.Stegomyia, Aedes.aegypti and Aedes.albopictus

Treatment

There is a vaccine for chikungunya. Travelers traveling to endemic areas may want to consider vaccination. There is no specific treatment. Avoiding mosquito bites is the only prevention.

Who is at risk?

There have been no cases of chikungunya in the US and US territories since 2019. Travelers to endemic areas are at risk. Endemic areas include Africa, the Americas, Asia, Europe, and islands in the Indian and Pacific Oceans. Travelers should check with the CDC travel website to see if outbreaks are occurring at their destinations.

Zika Virus

Like Dengue and chikungunya, Zika circulates between mosquitos and humans. If a mosquito bites a person infected with Zika virus in the first week of infection, the mosquito carries Zika to the next person it bites. Zika can also be transmitted through sex and can be transmitted from a pregnant mother to her fetus. Zika can cause severe birth defects when a pregnant mother is infected.

Symptoms

Most infected people have no symptoms, and when symptoms occur they tend to be mild. They include fever, rash, headache, joint pain, conjunctivitis (red eyes) and muscle pain. Symptoms are rarely severe enough to need hospitalization. The biggest problem with Zika is the birth defects caused by infection of pregnant women.

Species that transmit the disease

Aedes. aegypti and Aedes. albopictus

Treatment

There is no vaccine or treatment for Zika virus.

Who is at risk?

There have been no local cases of Zika in the US or US territories since 2019. People most at risk are travelers to countries that have outbreaks. Outbreaks occur in Mexico and South America and in certain countries in Africa and India. Other countries including the US have the Aedes species that can transmit Zika. Travelers to these areas should check with the CDC about current Zika outbreaks.

Yellow Fever

Yellow fever virus is maintained in forests between mosquitos and monkeys. People who work in forests where monkeys live can contract the virus this way. Mosquitos biting infected people can also spread the virus when mosquitos bite other people. Epidemics in urban areas occur this way.

Symptoms

Most people infected with yellow fever virus will either have no symptoms or mild symptoms and completely recover. Symptoms can include sudden onset of fever, chills, severe headache, back pain, general body aches, nausea, vomiting, fatigue, and weakness. Most people who develop symptoms improve within one week. A few people will develop a more severe form of the disease. Severe symptoms include high fever, yellow skin or eyes (jaundice), bleeding, shock, and organ failure. Among those who develop severe disease, 30-60% die

Species that transmit the disease

Primarily Aedes Aegypti

Treatment

There is an effective vaccine for prevention of yellow fever. Travelers going to an endemic yellow fever region should receive the vaccine before they travel. There is no treatment once someone has yellow fever.

Who is at risk?

There is no local transmission of yellow fever in the US. Yellow fever in travelers only rarely occurs. Yellow fever is endemic in Africa and South America.

Malaria

Malaria is caused by a parasite that resides in the liver and then infects red blood cells. It is maintained by circulation between mosquitos and humans. Mosquitos get infected from biting humans with malaria and then can transmit the parasite by biting other humans.

Symptoms

Malaria symptoms range from very mild illness to severe disease and even death. Early symptoms can include: Fever and flu-like illness, Chills, Headache, muscle aches, and tiredness. Nausea, vomiting, and diarrhea may also occur. If not treated quickly, the infection can become severe. Severe symptoms can include kidney failure, seizures, mental confusion, coma and death.

Species that transmit the disease

Anopheles

Treatment

Malaria can be treated successfully with several different drugs depending on the type and resistance. There are drugs that travelers can take if they are traveling to an area where malaria is present that will prevent infection. The newest development is a malaria vaccine that can be given to children in endemic malaria regions.

Who is at risk?

There is virtually no local transmission of malaria in the US in modern times. In a typical year, the U.S. reports about 2,000 cases of malaria, almost all of which are in travelers who have been to an endemic region. Malaria occurs only in tropical regions and below 6,500 feet above sea level. Most cases of malaria occur in sub-Saharan Africa, but it also occurs in parts of Oceania (such as Papua New Guinea) and in parts of Central and South America and Southeast Asia. Worldwide, malaria has caused 608,000 deaths in the past year. Malaria is one of the world’s most severe public health problems, with nearly half of the world’s population at risk for infection.

How to prevent mosquito bites.

Indoors

Make sure all windows have screens and any holes in the screens are patched. Use air conditioning if you have it during the spring and summer when mosquitos are most active.

Outdoors

Mosquitos lay eggs in standing water. Remove or empty any receptacles outside that allow water to pool such as saucers under flower pots. Tightly cover any water storage containers. If you have a birdbath, use a battery or solar powered agitator. Mosquitos only lay eggs in still water.

Residential outdoor misting systems that use permethrin provide good mosquito control and are safe for humans, birds and animals. They are somewhat expensive, however.

Use an EPA-registered insect repellant with one of the following ingredients:

  • DEET (Has been shown to be non-toxic for humans and repels but does not kill insects)
  • Picaridin (known as KBR 3023 and icaridin outside the United States)
  • IR3535
  • Oil of lemon eucalyptus (OLE)—A plant-derived ingredient (must be applied more frequently than DEET)
  • Para-menthane-diol (PMD)
  • 2-undecanone—A plant-derived ingredient

Wear loose long sleeved shirts and long pants when outside when mosquitos are active

Treat items such as boots, pants, socks, and tents with permethrin or buy permethrin-treated clothing and gear.

Bottom Line

Mosquitos transmit many diseases, but all of these are quite rare in the US. Global warming may well increase mosquito transmitted diseases in the US in the future. The vast majority of mosquito bites in the US are just a nuisance and do not transmit disease. In other parts of the world mosquito disease transmission is a major public health problem. Travelers to areas where mosquito borne diseases are prevalent should use mosquito bite prevention strategies, especially EPA-approved insect repellents. Travelers to areas endemic for yellow fever should be vaccinated prior to travel. Travelers to malaria prevalent regions should start preventive medicine 1 week before and continue 1 week after travel.

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Flesh Eating Bacteria – How Worried Should You Be

There have been several articles in the news recently about so called “flesh eating bacteria” and about how the incidence is increasing. Flesh eating bacteria is a popular name for a condition called necrotizing fasciitis. Several different kinds of bacteria can cause this condition, primarily in people who have other risk factors. In this post I will write about the symptoms of necrotizing fasciitis, what kinds of bacteria cause it, where they can be found, who is at risk, and what treatments there are.

What is necrotizing fasciitis?

Necrotizing fasciitis is a soft tissue infection that causes death of the connective tissue around the muscles. This infection typically travels along the connective tissue, which has a poor blood supply, leaving the overlying skin and subcutaneous fat initially unaffected. This can cause a delay in diagnosis and treatment. The infection can rapidly spread and cause a secondary infection of the overlying and underlying skin, soft tissue, and muscle. If not treated quickly it can cause sepsis (blood poisoning) which can rapidly lead to multiple organ failure and death.

How is necrotizing fasciitis treated?

The treatment for necrotizing fasciitis includes both antibiotics and surgery. Prompt administration of intravenous antibiotics limit the spread of infection and surgery is used to remove the dead and infected tissue. Sometimes this can even involve amputation of a limb. Time is of the essence in treatment. Necrotizing fasciitis can progress to death within just a few days.

What causes necrotizing fasciitis?

The most common bacteria that cause necrotizing fasciitis are strep and staph that live on the skin and usually enter the body through a break in the skin such as a cut or scrape.

The organism that has been in the news recently is called vibrio vulnificus, which lives in warm salt water or brackish water. More about this organism shortly.

Vibrio Vulnificus

Vibrio vulnificus lives in salt water or brackish water, usually at a temperature of 68 degrees Fahrenheit or higher. Most infections have occurred on the Gulf coast, but because of increasing warm oceans, it has been found further north, moving north at about a half a mile a year. There have now been vibrio infections documented in North Carolina, Connecticut and New York. This is a rare cause of necrotizing fasciitis, but is increasing in frequency. Infections usually occur when someone wades in contaminated salt water with a cut or scrape on the leg. There is no clue to let you know whether salt water is contaminated or not. It is no less clear than uncontaminated sea water.

What are the risk factors for necrotizing fasciitis?

Anything that compromises the immune system increases the risk of getting necrotizing fasciitis if you are exposed. Here is a list of risk factors:

  • Diabetes
  • Chronic disease
  • Immunosuppressive drugs (eg, prednisolone)
  • Malnutrition
  • Age > 60 years
  • Intravenous drug misuse
  • Peripheral vascular disease
  • Renal failure
  • Underlying malignancy
  • Obesity (BMI greater than 30)

If you have none of these risk factors, your chance of getting necrotizing fasciitis, even if exposed is very very low.

What can I do to prevent necrotizing fasciitis from vibrio vulnificus?

Even if you are healthy and have no risk factors, it is not a good idea to wade in salt water at the beach if you have a cut or scrape on a leg or arm. If you do get cut at the beach, get out of the water immediately and wash the cut thoroughly with soap and water. Even though your risk of getting necrotizing fasciitis may be very low, you don’t want to take any chances of getting this life threatening disease.

Certainly if you have any of the risk factors listed above, these precautions are especially important.

Bottom Line

Flesh eating bacteria is a scary name. The news media seize on a name like this because of the shock value. Necrotizing fasciitis, which is the correct term, does not have the same shock value. Nonetheless, this is a very serious and life threatening condition caused by multiple different kinds of bacteria. Healthy people have a very very low risk of getting this condition. Vibrio Vulnificus can cause necrotizing fasciitis and lives in warm salt water or brackish water. You should not wade or swim in the ocean if you have a cut or scrape on your leg or arm, especially if you have any of the risk factors mentioned above.