Diseases and Vectors We Study


Chiggers are tiny, six-legged wingless larvae that mature to become a type of mite. Chiggers are typically found in tall grass, weeds and the edges of woodlands. Their bite causes severe itching and red pimple-like bumps or hives. Chigger bites can transmit the bacteria Orientia tsutsugamushi, which causes scrub typhus, a disease without a vaccine. AFRIMS conducts surveillance for chiggers and scrub typhus across Southeast Asia.


Chikungunya is an emerging disease spread by Aedes aegypti and Aedes albopictus mosquitoes found across Africa, Asia and the Americas. Currently there are three genotypes of chikungunya virus: West African, East-Central-South African and Asian. Each genotype has contributed to outbreaks over time but in 2004, the ECSA and Asian genotypes began to expand significantly leading to increased cases worldwide. In acute disease, chikungunya infection can lead to high fever, profound joint pain and a rash similar to dengue virus. A key difference to dengue is the chronic, debilitating arthritis that can develop in up to 30-40% of cases and can lead to severe morbidity. It's global distribution, potentially severe consequences and lack of preventive vaccines make it a significant threat to deployed Service Members in endemic areas. 
Entomology | Virology


Infecting over 390 million individuals worldwide, dengue remains a persistent threat to deploying Service Members. As a mosquito-borne disease, spread by the same vector as chikungunya and Zika, increased global temperatures combined with continued urbanization and travel serve to increase the likelihood of exposure to dengue's four serotypes. Dengue is particularly dangerous, due to the potential for ADE and severe dengue (previously termed dengue shock syndrome or dengue hemorrhagic fever by the World Health Organization's 1997) which can be associated with mortality rates of 1% with proper care but up to 26% without. Current treatments address symptoms and disease management primarily focuses on prevention through vector control. However, vector control is increasingly complicated by insecticide-resistance in mosquitoes and the lack of a safe vaccine.
Entomology | Veterinary Medicine | Virology 

Diarrheal Vectors

Diarrhea remains a leading cause of acute morbidity among civilian and military members alike, negatively impacting the health and functionality of both populations. U.S. military personnel often are deployed into developing regions in which enteric pathogens associated with diarrheal disease are prevalent. Documented studies from previous exercises in Thailand demonstrated that U.S. Soldiers suffer consistent diarrhea attack rates during their first few weeks in-country. Acute diarrhea in deployed military personnel increases health care service utilization, contributes to a major loss of work-hours and adversely impacts operational readiness. While a number of strategies have been used to mitigate this threat to military personnel, diarrhea, and the associated increases in antimicrobial resistance of enteric bacterial pathogens, remains a primary concern for force health protection.
Bacterial and Parasitic Diseases | Veterinary Medicine


Gonorrhea is a sexually transmitted disease that can infect both men and women. Caused by the Neisseria gonorrhoeae bacterium, gonorrhea can cause infections in the genitals, rectum and throat. Although treatable, drug-resistant forms of gonorrhea are increasing in prevalence. If left untreated, gonorrhea can lead to pelvic inflammatory disease, ectopic pregnancy, infertility and increased risk of HIV infection. Gonorrhea can also be passed from mother to child and cause blindness or life-threatening infections in the infant. As part of its work to track and characterize multidrug-resistant organisms, AFRIMS studies works with host-nation partners to study gonorrhea across Southeast Asia.
Bacterial and Parasitic Diseases | Retrovirology 

Human Immunodeficiency Virus (HIV)

HIV is the virus that causes AIDS. Although extraordinary progress has been made in the fight against new HIV cases and AIDS deaths, currently 38 million people are living with HIV, with 1.7 million people being newly infected and 690,000 people dying from AIDS-related illnesses in 2019. It remains a significant public health threat with the potential to significantly destabilize governments and economies. In military contexts, it is a significant danger to the walking blood bank during combat casualty care, making effective screening and prevention strategies a top priority for deployed medicine. Addressing the threat of HIV to military and global populations is of critical concern to health diplomacy and international security and a challenge that requires sustained commitment to research and developing effective scientific, clinical, political, and social solutions.
Retrovirology | Veterinary Medicine


Influenza is generally a self-limited disease characterized by abrupt onset of high fever, cough, sore throat or fatigue lasting for several days. Severe disease including pneumonia as well as bacterial superinfection can occur and is typically found in the elderly, very young and chronically ill or immunocompromised. Influenza is notable for its capacity for both antigenic drift and antigenic shift which lead to heightened risk for epidemic spread. Given its ability to spread rapidly through confined spaces and varying efficacy of vaccines from year to year, influenza represents a significant threat to force health protection, contributing to lost duty days.


Malaria remains the most significant parasitic disease in the world. Transmitted through the bite of an infected Anopheles mosquito, nearly half of the global population is at risk, with an estimated 216 million cases per year in 91 countries. While progress has been made to reduce the burden of malaria around the world, rising resistance to existing malaria drugs and insecticides, geopolitical instability and increasingly inaccurate rapid diagnostic tests threaten these accomplishments. As such, it is a significant threat to both public health and deployed U.S. military forces, the majority of whom lack immunity to the parasite. Addressing the threat of malaria to military and global populations is of critical concern to health diplomacy and international security and a challenge that requires sustained commitment to research and developing effective scientific, clinical, political and social solutions.
Bacterial and Parasitic Diseases | Entomology | Veterinary Medicine


Mosquito-borne pathogens are among the most prevalent and dangerous threats to deployed Service Members, public health and regional stability. Diseases like dengue, malaria and Zika exist cyclically, where an infected mosquito spreads the disease to a human or vertebrate host who then spreads the disease back to a new mosquito when bitten again. While public health strategies using bite prevention technologies (bed nets, treated clothing, etc), repellents and preventive drugs and vaccines have made some progress in mitigating the burden, their efficacy is limited by rising resistance amongst pathogens and their vectors. Furthermore, as the climate changes and mosquitos are able to survive in more areas of the world for more months out of the year, new regions are threatened by the diseases they carry. These dangers underscore the importance of active surveillance of both mosquitoes and the diseases they carry to inform public health efforts and responsive drug and vaccine development. 


Rodents such as rats and mice are associated with a number of health risks and are known to spread more than 35 diseases. These diseases can be spread to humans directly through bites, handling of live or dead rodents and contact with rodent feces, urine or saliva. Diseases carried by rodents can also be spread to humans indirectly through fleas, ticks or mites that have fed on an infected rodent.


With over 89 million cases and greater than one million deaths worldwide (as of 10 Jan 2021 per the World Health Organization), severe acute respiratory syndrome coronavirus 2, the causative virus of coronavirus disease 2019, has had impacts far and wide. A betacoronavirus in the same family as severe acute respiratory syndrome coronavirus 1 and Middle East Respiratory Syndrome coronavirus, the relative ease of transmission of this respiratory pathogen combined with limited treatment and initial absence of vaccine have led to much interest and study since initial discovery in late 2019. One of the troubling observations is that people who are infected with SARS-CoV-2 can transmit the virus to others before they have symptoms or without ever having symptoms of disease. Its emergence and rapid spread poses a significant danger to Service Members and civilians alike around the world. 
Retrovirology | Veterinary Medicine | Virology

Scrub Typhus

Scrub typhus, also known as bush typhus, is a disease caused by a bacteria called Orientia tsutsugamushi. Scrub typhus is spread to people through bites of infected chiggers (larval mites). The most common symptoms of scrub typhus include fever, headache, body aches and sometimes rash. Most cases of scrub typhus occur in rural areas of Southeast Asia, Indonesia, China, Japan, India and northern Australia. Anyone living in or traveling to areas where scrub typhus is found could get infected and there is no vaccine to prevent this disease. AFRIMS scientists work across Southeast Asia to track the incidence of this disease. 
Entomology | Veterinary Medicine


Tick-borne diseases, which afflict humans and other animals, are caused by infectious agents transmitted by tick bites. They are caused by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses and protozoa. Because individual ticks can harbor more than one disease-causing agent, patients can be infected with more than one pathogen at the same time, compounding the difficulty in diagnosis and treatment. 16 tick-borne diseases of humans are known, of which four have been discovered since 2013. As the incidence of tick-borne illnesses increases and the geographic areas in which they are found expand, health workers increasingly must be able to distinguish the diverse, and often overlapping, clinical presentations of these diseases. 


Zika virus is a mosquito-borne disease found around the world. Spread by Aedes mosquitoes, it is frequently found in urban environments and is likely to spread as humans expand into more areas. Distinguishing it from other flaviviruses, Zika has a relatively high rate of asymptomatic infection, can be spread through blood or sexual contact and can be found in bodily fluids for weeks to months after initial infection. Currently there is no treatment for Zika and disease management is primarily focused on symptoms with particular care required for pregnant patients due to the risk of transmission to the baby and ensuing severe morbidities. As such, AFRIMS conducts surveillance and countermeasure development work to detect and combat Zika to maintain force health protection for both Service Members and their families when they return home from deployment to an endemic region. 
Entomology | Retrovirology | Veterinary Medicine | Virology 


Zoonoses are pathogens that jump from animals to humans. These diseases particularly relevant to areas where humans are frequently in contact with animals, particularly those that were previously undisturbed. Zoonotic diseases are particularly relevant to Soldiers from home station to dense, urban or subterranean environments, where they can come into contact with endemic diseases like multidrug-resistant bacteria as well as emerging viruses like SARS-CoV-2 or Ebola. Furthermore, they significantly impact food security, the environment and more, threatening global health and stability. The growing focus on zoonotic disease is part of One Health, a transdisciplinary, multisectoral approach to optimizing health that recognizes the interrelatedness of human health, animal health and the environment. AFRIMS surveils zoonotic diseases among animal populations to inform countermeasure development efforts across Southeast Asia. 
Veterinary Medicine