Ticks are found all over the US except in the desert southwest. They can carry many diseases, but ticks that carry diseases are usually localized to certain regions of the country. Whether you should worry about a tick bite depends on where you live. In this post I’m going to write about the diseases that ticks carry and what parts of the country have the majority of cases. I will also provide advice that will help you avoid getting tick borne diseases even if you live in a part of the country where a tick borne disease is prevalent.
Lyme Disease
Lyme disease is the most common tick borne disease. It is so named, because the bacteria that causes it (borelia bergdorfori) was discovered in Lyme, Connecticut. The bacterium is a spirochete, and like syphilis, which is also a spirochete, if untreated it can cause disease in many organ systems of the body.
Symptoms
The first symptom of Lyme Disease is a circular rash that spreads from the site of the tick bite. It usually develops in 7-10 days but can be delayed for up to 30 days. It is called erythema chronicum migrans. Often there are no symptoms, but sometimes the rash is associated with fever and muscle aching. At this early stage, the antibody,blood test for Lyme Disease is negative. Only about 80% of people infected with Lyme Disease have the characteristic rash of erythema chronicum migrans. The other 20% may have flu-like symptoms at the beginning of the infection. A few people have no symptoms until swollen painful joints develop several weeks or months after the initial infection.
If left untreated, the rash disappears and any associated fever and muscle pain disappear as well. Weeks to months later arthritis may appear especially in the knee joints, usually with fluid in the joints. The disease can go on to infect the nervous system and/or the heart. Other symptoms can be persistent fever, chronic fatigue, and recurrent skin rashes.
Treatment
The treatment for Lyme Disease at any stage is 2-4 weeks of an antibiotic called doxycycline 100 mg twice a day. High dose amoxicillin also works. At the stage of erythema chronicum migrans, the treatment is for two weeks. For later stages the treatment should be continued for 3-4 weeks.
Four weeks of doxycycline or amoxicillin kills all the organisms. There is no reason to treat longer than that with antibiotics. Unfortunately, a few people have persistent joint pain or other symptoms even after adequate treatment. This is not persistent infection with the Lyme Disease organism, but it seems that rarely the Lyme Disease organism can cause an autoimmune reaction that persists even after all the Lyme bacteria are killed. Some so-called Lyme Disease experts treat people with chronic symptoms with very long courses of intravenous antibiotics. There is absolutely no evidence that this does any good for these unfortunate people and may do them considerable harm.
Where in the country do ticks carry Lyme Disease?
Lyme disease occurs almost exclusively in the east, particularly the northeast. Here is a map showing where ticks transmit Lyme Disease.
How to prevent getting Lyme Disease
If you live in one of the high Lyme Disease parts of the country, there are several thing you can do to prevent getting Lyme Disease.
- When walking in an area where there may be ticks, wear long pants with pant legs tucked into your socks. Insect repellant, especially DEET decreases the chance of a tick bite.
- When you have been walking or working in high grass or in the woods, check yourself for ticks every day. A tick has to be attached for 36 hours to transmit Lyme Disease. If you remove all ticks within 24 hours, there is no risk of getting Lyme Disease. You may need to have a partner check the spots on your skin that you can’t see. The correct way to remove tick is to grasp the tick with a tissue or a pair of tweezers and just pull it straight out. The head of the tick does not stay in the skin, so don’t worry about that.
- Ticks tend to get on your clothes first and then move to the body. If you put all your clothes in your clothes dryer when you return from tick country, twenty minutes on high setting will kill any ticks on your clothing.
- If you find a tick that could have been on for more than 24 hours, call your doctor for prophylactic doxycycline. As single dose of 200 mg of doxycycline will keep you from getting Lyme Disease.
Tularemia
Tularemia is caused by a bacterium called Francisela tularensis. It is most commonly transmitted by ticks, but is also carried by bites of deer flies and by rabbits. People who hunt wild rabbits and clean them can be exposed that way. It can also be carried by squirrels and other rodents.
Symptoms
The symptoms of Tularemia depend on how you get infected. Tularemia from tick bites or deer fly bites is called ulceroglandular tularemia. Symptoms usually begin anywhere from 3-15 days after the tick or fly bite. The bite looks red, swollen and infected with tender lymph nodes on the side of the bite. Fever is almost always present. It takes about 4 weeks after symptoms begin before the antibody test turns positive, so lit is important to treat based on typical symptoms rather than a blood test. Untreated tularemia is a severe disease and can cause death in both animals and humans. There are several other types of tularemia, named by the site infected. Infection starting in the eye is called oculoglandular tularemia. The most severe form results from inhaling contaminated dust or hay. It is called pneumonic tularemia and can be lethal if not recognized and treated promptly.
Treatment
Antibiotics used to treat tularemia include streptomycin, gentamicin, doxycycline, and ciprofloxacin. Treatment usually lasts 10 to 21 days depending on the stage of illness and the medication used. Symptoms may last for several weeks, but people who are treated appropriately almost always recover completely.
Where in the country do ticks, deer flies and rodents carry tularemia
Although there have been a few small epidemics in the east on Martha’s Vineyard, the vast majority of cases occur in Arkansa, Missouri and Oklahoma. I practiced medicine in Arkansa for many years and regularly saw cases of tularemia every spring and summer. Here is a map showing the distribution of tularemia cases in 2020.
How to avoid getting infected with tularemia.
If you live in Arkansa, Missouri or Oklahoma you are at risk for getting tularemia. All the same things for avoiding getting Lyme Disease also work for tularemia. The only difference is that insect repellant is even more important because deer flies carry tularemia also. If you hunt wild rabbits, use gloves to clean them. It is not certain how long a tick has to be attached to transmit tularemia. It is at least several hours, but probably less than 24 hours. Immediate tick checks after you come in from tick country will help you avoid tularemia. There is no prophylactic antibiotic treatment for tularemia, so if you remove an attached tick, be on the lookout for the symptoms of uleroglanular tularemia. The sooner you start treatment, the better.
Anaplasmosis and Ehrlichiosis
Both of these tick borne diseases are indistinguishable from a symptom standpoint. They have different names because they are caused by slightly different organisms. Anaplasmosis is caused by Anaplasma phagocytophilum. Ehrlichiosis is caused by Ehrlichia chaffeensis, E.ewingii, or E.muris eauclairensis.
Symptoms
symptoms of anaplasmosis and ehrlichiosis include fever, severe headache, muscle aches, chills and shaking and, less frequently nausea, vomiting, loss of appetite, weight loss, abdominal pain, cough, diarrhea, aching joints. and confusion. Lab work often shows a low white blood cell count and elevated liver enzymes.
Treatment
The treatment for both anaplasmosis and ehrlichiosis is doxycycline, 100 mg twice a day for 10-14 days. Fever is usually gone and symptoms start to improve within 24 hours of treatment. Once again, treatment should be based on typical symptoms in spring and summer in areas where both diseases are common. It takes 4 weeks before the antibody test becomes positive. The low white blood cell count and the elevated liver function tests occur at the same time as symptoms, so bloodwork showing these things helps to make the diagnosis.
Where in the country do ticks transmit anaplasmosis and ehrlichiosis?
Anaplasmosis and ehrlichiosis are most commonly reported in northeastern and upper midwestern states. Here is a map showing annual cases of anaplasmosis and ehrlichiosis.
How to avoid getting infected with anaplasmosis or ehrlichiosis
Ticks have to be attached for 12-24 hours to transmit either one of these diseases. If you live in one of the high risk areas for either of these diseases, all of the same strategies listed under prevention of Lyme Disease work to prevent anaplasmosis and ehrlichiosis.
Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever is probably the most serious of the tick borne diseases. It is caused by a rickettsial organism called Rickettsia rickettsii. It can cause loss of fingers and toes and death.
Symptoms
The initial symptom is fever. Shortly after the fever develops there is a characteristic rash on the wrists, forearms, and ankles and spreads to include the trunk and sometimes the palms of hands and soles of feet. Other symptoms include headache, nausea, vomiting, stomach pain, muscle pain and lack of appetite. If left untreated clots can form in the small arteries in the fingers and toes.
Treatment
Again the treatment is doxycycline 100 mg twice a day until fever subsides and symptoms have improved. The minimum length of treatment is 5-7 days.
Where in the country to ticks transmit Rocky Mountain Spotted Fever?
Rocky Mountain Spotted Fever has been reported throughout the continental United States, but five states account for 50% of the cases. These states are Arkansas, Missouri, North Carolina, Tennessee, and Virginia. It is transmitted by the American Dog Tick and cases tend to occur where there are lots of free roaming dogs. Here is a map of cases from the CDC.
How to avoid getting infected with Rocky Mountain Spotted Fever
In addition to all the things mentioned under avoiding Lyme disease, the one other thing that will help you avoid getting Rocky Mountain Spotted Fever is to make sure your dog or dogs maintain one of the three month treatments to prevent fleas and ticks.
Babeseosis
Babeseosis is sometime called “tick malaria” because, like malaria, the organism if a parasite that infects red blood cells. It is caused by two organisms: Babesia microti and Babesia divergens.
Symmptoms
Many people who are infected feel fine and do not have any symptoms. Some people develop nonspecific flu-like symptoms, such as fever, chills, sweats, headache, body aches, loss of appetite, nausea, or fatigue. Because red blood cells are infected, some people develop anemia. People who have have had their spleen removed are at particular risk of severe disease from babesiosis that can be life threatening.
Treatment
For ill patients, babesiosis usually is treated for at least 7-10 days with a combination of two prescription medications — typically either: Atovaquone PLUS azithromycin; OR. Clindamycin PLUS quinine. People with babeseois who are not ill don’t need to be treated. The infection will resolve on its own.
Where in the country to ticks transmit babesiosis?
Tickborne transmission primarily occurs in the Northeast and upper Midwest, especially in parts of New England, New York state, New Jersey, Wisconsin, and Minnesota. It is spread by ticks in the nymph stage, so they are very small and easily missed. Many people with babesiosis do not recall a tick bite. Here is a map of cases of babesosis. Some states don’t report cases, so cases in those states are unknown.
How to avoid getting infected with babesiosis
Ticks have to be attached for 36-48 hours to transmit the babesiosis parasite. Tick checks have to be done very carefully though because the nymph ticks are so small. Otherwise use the same tick precautions for Lyme Disease.
Tick Borne Relapsing Fever
Tick-borne relapsing fever (TBRF) is a rare infection linked to sleeping in rustic cabins, particularly cabins in mountainous areas of the western United States. It is caused mainly by a bacterium called Borrelia hermsii. Other organisms can cause the disease too. It can also be transmitted by body lice.
Symptoms
High fever (e.g., 103° F), headache, muscle and joint aches. Symptoms can reoccur, producing a telltale pattern of fever lasting roughly 3 days, followed by 7 days without fever, followed by another 3 days of fever. Without antibiotic treatment, this process can repeat several times.
Treatment
Doxycycline for 10 days or azithromycin.
Where in the country to ticks transmit tick borne relapsing fever?
How to avoid getting infected with tick borne relapsing fever.
In addition to the measures that are the same as the ones to prevent Lyme Disease, avoid sleeping in rustic cabins in the west!
Powassan Virus
So far, Powassan virus is a rare disease, which is a good thing. Although many people have no or only mild symptoms, some people get a severe encephalitis (infection of the brain). This is one disease that is transmitted in minutes by a tick bite.
Symptoms
Those who have symptoms have fever, headache, vomiting and weakness. People who get encephalitis or meningitis can have confusion, loss of coordination, difficulty speaking and seizures. About 1 out of 10 people with severe disease die from it. About half of the people who survive severe disease have long-term health problems such a recurring headaches, loss of strength and memory problems.
Treatment
There are no medicines to treat this virus. Treatment consists of supportive care. People who have no or only mild symptoms recover without long term health problems.
Where in the country to ticks transmit Powassan virus?
Powassan virus disease (Powassan) has been reported primarily from northeastern states and the Great Lakes region. Here is a map showing cases in the US.
How to avoid getting infected with Powassan virus
All of the tick prevention measures for Lyme disease are relevant if you live in the northeast or upper midwest. Tick checks only work if you find the tick before it attaches, since ticks can transmit the disease within minutes of a tick bite.
Other Tick Borne Diseases
There are several other tick borne diseases. Many of them have just recently been recognized. Here is a link to a CDC webpage that has a comprehensive list of tick borne diseases: Diseases Transmitted by Ticks.
Bottom Line
Ticks carry lots of diseases, but only in fairly limited parts of the country. If you don’t live in one of those areas, then tick bites are a nuisance but not a serious problem. If you do live in one of those regions, you should definitely take the precautions outlined under the section on Lyme Disease. I will reiterate those here for emphasis.
- When walking in an area where there may be ticks, wear long pants with pant legs tucked into your socks. Insect repellant, especially DEET decreased the chance of a tick bite.
- When you have been walking or working in high grass or in the woods, check yourself for ticks every day. A tick has to be attached for 36 hours to transmit Lyme Disease. If you remove all ticks within 24 hours, there is no risk of getting Lyme Disease. You may need to have a partner check the spots on your skin that you can’t see. The correct way to remove tick is to grasp the tick with a tissue or a pair of tweezers and just pull it straight out. The head of the tick does not stay in the skin, so don’t worry about that.
- Ticks tend to get on your clothes first and then move to the body. If you put all your clothes in your clothes dryer when you return from tick country, twenty minutes on high setting will kill any ticks on your clothing.
- If you find a tick that could have been on for more than 24 hours, call your doctor for prophylactic doxycycline. As single dose of 200 mg of doxycycline will keep you from getting Lyme Disease.
Ticks are likely to be found in brushy areas, areas of high grass and in the woods. Here is a picture of a tick in “questing” mode. If you brush by this tick, it will attach itself to you, either your clothes (most likely) or to your bare arms or legs if they brush by the questing tick.
I will leave you with that somewhat scary image!