Vector-borne disease control measures are often offered in the military when a service member is deployed to certain areas of the world. These types of countermeasures were developed to protect against infections spread by insects, rodents, and other animals. Insect-borne diseases, such as yellow fever, tick-borne encephalitis, Japanese encephalitis, and others, infect millions of people each year.
The military health system has a long history of providing medical countermeasures for insect-borne diseases. We spoke with two MHS experts to learn more about the different diseases and what MHS has done to combat them.
Dr. Cecilia Mikita is medical director of Defense Health Agency Healthcare and Immunization Division, North Atlantic Region, at Walter Reed National Military Medical Center. Dr. Margaret Ryan is the medical director of the DHA Health Care and Immunization Division, Pacific Region, at the Naval Medical Center in San Diego, California.
MHS Communications: What is tick-borne encephalitis?
Mikita: Tick-borne encephalitis is a potentially serious viral illness associated with the bites of infected ticks. The TBE virus is not found in the United States; it is isolated in specific geographic regions extending from western and northern Europe to eastern and northern Asia. The virus is mainly transmitted to humans by infected ticks, with the risk being highest between April and November. TBE-infected ticks are found in wooded habitats, and people who engage in outdoor recreational activities, including hiking and camping, or who may be exposed occupationally, are at greatest risk.
MHS Communications: What are the symptoms of tick-borne encephalitis?
Mikita: TBE is a potentially chronic and fatal neurological disease. Most people infected with the TBE virus experience flu-like symptoms such as fever, fatigue, headache, joint and muscle pain, and nausea that disappear within one to eight days. About a third of patients may progress to a second phase of neurological symptoms, including meningitis, encephalitis, myelitis and paralysis.
MHS Communications: How does this disease affect the military?
Mikita: Over the past 20 years, 20 cases of TBE have been diagnosed in Department of Defense beneficiaries who traveled to parts of Europe, China or Russia. The U.S. Army has excellent programs, including Armed Forces Health Surveillance Division disease tracking and Integrated Pest Control, to prevent exposure to virus-carrying ticks in at-risk areas of the world.
MHS Communications: Is there a vaccine against tick-borne encephalitis?
Mikita: TBE vaccines have been available in Europe since the 1970s. The currently available TBE vaccine was authorized by the United States Food and Drug Administration in 2021. The TBE vaccine is not a force health protection requirement , but it is strongly recommended for military service members and their family members who will travel to and live in high-risk areas of Europe and Asia and undertake risky activities.
MHS Communications: Who is the vaccine approved for?
Mikita: The vaccine is approved for people aged 1 year and older who are at risk of exposure to TBE. The primary vaccine series consists of three doses and a booster dose given at least three years after the primary series if there is a continued risk of exposure. This is a very effective vaccine, creating an excellent immune response in 99% of those vaccinated.
MHS Communications: How to protect yourself against TBE?
Mikita: Tick precautions are a very effective prevention strategy. The military’s integrated pest management program plays a crucial role in the prevention of TBE. Precautions include using DEET or picaridin, wearing long pants and sleeves, and treating clothing and equipment with Permethrin. Tick checks should be carried out on your body after being outside. Programs combining mosquito control and individual vaccination are very effective in preventing TBE.
MHS Communications: What is yellow fever?
Mikita: Yellow fever is a virus transmitted by mosquitoes and present in tropical and subtropical areas of South America and Africa. It is transmitted from one host to another via the bite of an infected mosquito.
MHS Communications: What are the symptoms of yellow fever?
Mikita: Symptoms can vary greatly from a mild febrile illness to a severe infection. The incubation period is usually three to six days. When experiencing symptoms, individuals experience a sudden onset of fever, chills, headache, back pain, muscle pain, fatigue, weakness, nausea, and vomiting. About 15% of individuals progress to a more serious or toxic form of the disease after a brief remission. Symptoms include high fever, jaundice, bleeding, shock and multiple organ failure. Twenty to 50% of severe cases with liver or kidney damage may die from yellow fever.
MHS Communications: Is there a vaccine against yellow fever?
Mikita: The first yellow fever vaccine was developed in 1938. The currently available vaccine is approved for people aged nine months and older. Yellow fever vaccine is required for military and civilian/DOD personnel deployed or traveling to yellow fever endemic areas, including South America and Africa. Vaccination may be required to enter certain countries. Most travelers require a single, lifetime dose of yellow fever vaccine. The yellow fever vaccine is very effective: 99% of people develop immunity within 30 days of vaccination.
MHS Communications: How to protect yourself against yellow fever?
Mikita: Mosquito control is an essential part of yellow fever prevention. Integrated pest management program, including the use of insect repellents and insecticides, is imperative to prevent yellow fever and other mosquito-borne infections. Programs combining mosquito control and individual vaccination are very effective in preventing yellow fever.
MHS Communications: What is Japanese encephalitis?
Ryan: Japanese encephalitis virus is a mosquito-borne virus found in Asia and many parts of the Western Pacific. JE virus is closely related to West Nile virus. The virus can infect birds, some farm animals and humans; Infected animals and people are sometimes called “hosts.” Mosquitoes transmit the virus between hosts; mosquitoes are called “vectors”.
MHS Communications: What are the symptoms of this disease?
Ryan: Although most people infected with the JE virus have only a mild fever or body aches, about one in 250 people infected with JE will develop encephalitis within one to two weeks after being infected . Encephalitis means “inflammation of the brain.” Encephalitis due to JE infection is characterized by high fever, severe headache, neck stiffness, confusion, seizures, and/or paralysis. JE infection is fatal in about one third of people who develop encephalitis. Of those who survive encephalitis after JE infection, approximately half will be disabled for life.
MHS Communications: Is there a vaccine against Japanese encephalitis?
Ryan: Yes, there is a very effective vaccine to prevent JE in humans. Vaccination is part of the routine childhood immunization program in Japan. It is mandatory for military personnel who travel or live in areas at risk of JE. JE vaccination is strongly recommended for military family members and others who travel to or live in areas at risk for JE.
The JE vaccine is recommended for everyone aged two months and older who is at risk of exposure to JE. The primary vaccine series consists of two doses, given at least one month apart. For people who remain or return to an area at risk of JE after their primary vaccination, a third dose can be administered one year later.
MHS Communications: When was the vaccine developed?
Ryan: JE vaccines have been available in the United States since 1992. The current vaccine, abbreviated JE-VC, was licensed by the FDA in 2009.
MHS Communications: How to protect yourself against JE?
Ryan: The military’s integrated pest control program, which includes the appropriate use of insecticides and repellents, is essential for preventing JE as well as other mosquito-borne infections. Programs combining mosquito control and individual vaccination are very effective in preventing JE.
