VECTOR-BORNE ILLNESSES

CDC – Lyme Disease
Lyme disease is caused by two different bacteria, Borrelia burgdorferi and Borrelia mayonii. The most common cause is Borrelia burgdorferi. Both bacteria are transmitted to humans through tick bites. This bacterium is not immediately transmitted when a tick bites, the tick must be attached for 36 to 48 hours or more before the bacteria can be transmitted. Symptoms of Lyme disease include fever, headache, fatigue, and a skin rash called erythema migrans, sometimes called a “bull’s-eye rash”. If Lyme disease is left untreated it can also cause infection in the joints, the heart, and the nervous system. Lyme disease is usually treated successfully with a few weeks of antibiotics.

The ticks that are known to carry the two different bacteria that cause Lyme disease are not known to live in Idaho. It is still important to take measures to avoid tick bites, as the ticks in Idaho carry other diseases.

CDC – Lyme Disease Map
Most cases of Lyme disease in the United States occurs in the northeastern region, so precautions to avoid ticks should be taken when visiting those regions. The Centers for Disease Control and Prevention has a map (in the link above) showing where Lyme disease usually occurs in the US. Some precautions to avoid tick bites include treating clothing with a repellent and using repellent that is safe to apply to the skin, using pet safe tick treatments on pets, and avoiding areas where ticks live such as heavily wooded or grassy areas. After coming inside from an area that may have had ticks, perform a tick check of equipment, body, and pets.

CDC – Malaria
Malaria is a disease caused by a parasite transmitted to humans by mosquitoes. If infected with the parasite an individual will typically experience fever, chills, and other flu-like symptoms, such as body aches. If left untreated, malaria can cause severe illness or even death, however effective treatment exists to treat the disease.

The parasite that causes malaria has not been detected in the US since 1951. Most of the cases of malaria that occur in the US are related to travel to countries where malaria is common. When traveling, there are precautions to take to avoid exposure to the parasite, such as avoiding mosquito bites by using repellents and insecticides as directed on packaging, sleeping with bed nets, wearing clothing that covers as much skin as possible to avoid bites, and potentially taking a medication that prevents malaria while traveling. Consult your physician to determine if medication would be appropriate to use if  you are traveling to an area where malaria is common.

CDC – Plague
Plague is an infection that can affect humans and other mammals caused by the bacterium Yersinia pestis. It is usually transmitted to humans through a bite from a flea infected with the bacteria. It can also be transmitted to humans by handling an infected animal. If infected, individuals usually experience fever, chills, weakness, stomach pain, shock, possible bleeding into skin and other organs, and skin and other tissues may turn black and die.

When people think of the plague, they might think of the disease that killed millions of people during the Middle Ages, however, today we have modern antibiotics that are effective at treating plague. It is important to seek prompt treatment though, as without treatment it can still lead to serious illness or death. Treatment is also available for pets if they become ill.

In Idaho, ground squirrels are carries of plague and people are at highest risk of exposure to these animals from March through July. Individuals can protect themselves from exposure by avoiding the animals and making their homes rodent proof. If it is a possibility to encounter animals or fleas, such as during camping or hiking, insect repellent can provide some protection. Since plague can infect other mammals besides humans, it is important to keep pets flea-free as well by using flea control products. Use any repellents and flea-control products as instructed on the product label.  

CDC – Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever (RMSF) is an infection caused by the bacterium Rickettsia rickettsii. This bacterium is transmitted through the bite of an infected tick. It is unclear how long a tick must be attached to transfer this particular bacterium, but evidence suggests it would need to be attached for at least four hours before transmission can occur. Symptoms of RMSF include fever, headache, rash, nausea, vomiting, stomach pain, muscle pain, and decreased appetite. If the disease is not treated properly, it can rapidly progress to a life-threatening illness. There is an effective antibiotic treatment for RMSF available.

There are several types of ticks that can carry and transmit this bacterium. Some of these ticks are found in Idaho so it is important to avoid tick bites or quickly remove ticks if they do attach. Some precautions to avoid tick bites include treating clothing with a repellent and using repellent that is safe to apply to the skin, using pet safe tick treatments on pets, and avoiding areas where ticks live such as heavily wooded or grassy areas. After coming inside from an area that may have had ticks perform a tick check of equipment, body, and pets.

CDC – Tick-borne Relapsing Fever
Tick-borne Relapsing Fever (TBRF) is an infection caused by several different species of the bacteria Borrelia. These bacteria are transmitted through the bite of a “soft body tick”. These ticks are different from the ticks that cause Lyme disease and RMSF in that their bite and attachment is short-lived, only lasting about half an hour and instead of living in heavily forested areas and tall grass they tend to live in rodent burrows. Symptoms of TBRF are high fevers, headache, and muscle and joint pain. These symptoms usually reoccur in a pattern of fever lasting about three days with a period of seven days without a fever, before the fever occurs again. This cycle can repeat itself several times if not treated. There is an effective antibiotic treatment for TBRF available that stops this cycle.

There are several types of ticks that can carry and transmit these bacteria and they are generally found in mountainous areas, including Idaho. Most people encounter the ticks that carry this disease when staying in cabins that have rodents in them. The ticks usually come out at night and attach for a short amount of time. Most of the time people are unaware they have even been bitten by one of these ticks. To prevent bites from these ticks it is important to not sleep in rodent-infested buildings whenever possible, get a professional to remove the rodents and rodent proof the building, and use insect repellent to prevent tick bites.

CDC – Tularemia
Tularemia, sometimes referred to as “rabbit fever”, is an infection caused by the bacterium Francisella tularensis. This bacterium can be transmitted to humans in multiple different ways such as tick and deer fly bites, skin contact with infected animals (usually rabbits), drinking contaminated water, and inhaling contaminated dust. The symptoms of tularemia vary depending on how an individual was infected but all forms of the disease cause fever and lymph node swelling. This bacterium can cause infections of the skin, eyes, throat, or lungs. There are several antibiotic treatments that are effective at treating tularemia.

Tularemia infections are rare, but have occurred in all states except Hawaii, so it is possible to become infected in Idaho. There are steps to take to avoid being exposed to the bacteria including using insect repellent, wearing long pants and sleeves to avoid tick and fly bites, removing ticks when they are attached, avoid drinking untreated surface water, and do not mow over sick or dead animals. Some specific recommendations for hunters include wearing gloves when handling animals, especially rodents, and cooking game meat thoroughly before eating.

CDC – West Nile Virus
West Nile Virus is a viral infection carried by mosquitoes. It is the most common infection from mosquitoes in the US. The virus can, rarely, also be spread through blood transfusions or during pregnancy, delivery, or breast feeding.

Most people who are infected never develop any symptoms from the virus. Many people who develop symptoms will have fevers, headaches, body aches, joint pains, vomiting, diarrhea, or rashes. These individuals tend to feel tired and weak for weeks or even months after the infection. Few people will develop a more serious infection causing encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord). These individuals may experience high fevers, headaches, neck stiffness, disorientation, tremors, convulsions, muscle weakness, vision loss, numbness, paralysis, comas, and, sometimes, death. This severe illness can occur in anyone but is more common in individuals over 60 years of age and those with immunocompromising health conditions. There is no specific treatment for West Nile virus, but rest, fluids, and over-the-counter pain medications are advised. For those with serious illness, hospitalization will often be required to offer supportive treatment and care.

West Nile Virus is here in Idaho and the best protection against the virus is preventing mosquito bites. To help protect against mosquito bites individuals should use insect repellent as directed, dress in clothing that covers more skin such as long pants and sleeves, treating clothing with an insect repellent as directed, and using methods to control mosquitoes inside and outside the home. Avoid having mosquitoes inside by using screens on windows and doors and using air conditioning when possible so they don’t have a way inside the home. Outside, any container that holds water should be covered so they cannot get in, or emptied once a week, so the mosquitoes cannot lay eggs in or near the water.