The importance of mosquitoes and other arthropods as vectors of human pathogens throughout the world has been appreciated since the early part of the 20th century. In spite of the extensive work that has been done on some groups in various geographic regions, there is a great lack of modern biosystematics information for most vectors in all areas of the world. The widespread distribution of malaria coupled with the resurgence of drug resistant strains, periodic epidemics of encephalitis and dengue fever, and the discovery of new arboviruses in most parts of the world, have made it necessary to conduct detailed studies of the vector groups of mosquitoes and other arthropods. To effectively control the vectors and prevent arthropod-borne diseases, it is necessary to complete meticulous studies of the vector groups, define the specific characteristics of each species, and develop reliable means of recognizing these species.

The military, in times of conflict or natural disaster, requires rapid response measures to protect soldiers and civilians from disease-vectors and nuisance-biting arthropod populations. History provides many examples of conflicts and battles, the outcomes of which were influenced by diseases transmitted by arthropods. Accurate vector identification and a knowledge of vector biology are essential for arthropod-borne disease risk assessment and for development of appropriate strategies for vector suppression, arthropod-borne disease reduction, and vaccine and drug development. Suppression of vectors of disease and nuisance biters through appropriate control or suppression measures is essential to reduce non-battle casualties and conserve the fighting force.


The purpose of the WRBU is to conduct laboratory and field research on the systematics of medically important arthropod species and species groups in support of epidemiological studies and disease control strategies of importance to the military. Research efforts are carried out worldwide, with regionalization or faunistic restrictions dictated by available material and military requirements. In all cases, research efforts have the development of accurate and reliable means of identifying vectors of human arbopathogens as their primary aim. These efforts also have the following objectives:

  1. to describe and illustrate all the species in the study
  2. to resolve any taxonomic problems,
  3. to develop effective keys for identifying all life stages of the species under study,
  4. to provide basic biological and ecological data useful in understanding the epidemiology and prevention of diseases and the control of vector species,
  5. to provide data concerning the medical importance of each species, and
  6. to train personnel in field studies and biosystematics research.

A collaborative multidisciplinary approach to biosystematics is used when feasible and necessary. This approach, primarily relevant to sibling species groups, may include all or a combination of the following scientific methodologies:

  1. morphology (all life stages),
  2. cytogenetic (chromosomal) studies,
  3. molecular (DNA and protein electrophorectic) studies,
  4. crossmating (genetic) studies, and
  5. ecological studies (including habitat preference, biting behavior, vector competence, and distribution).

Current Status

Over 12,000 pages have been published in 392 publications (senior authorship attributed to 14 military officers, 11 civilian employees, and 31 adjunct personnel). A total of 58 revisionary studies and major identification keys/guides have been published, each comprising 24 or more pages, 24 of which were over 100 Pages long.To date, 189 new species of mosquitoes and 61 new species of ceratopogonid biting midges have been described. Many of these new species are members of sibling species complexes involving vectors of human pathogens. Our increased ability to identify these vectors permits the development of more effective and efficient control measures and enhances studies of disease ecology.

The number of mosquito specimens (all life stages) deposited in the National Museum of Natural History (Smithsonian Institution) has increased from approximately 200,000 in 1961 to approximately 1.5 million. The collection is the largest and most diverse resource for mosquito biosystematics research of its kind in the world. Of the nearly 3,300 species currently recognized, approximately 1,400 name-bearing type specimens (reference standards) are deposited in the collection.

Efforts to obtain properly collected and prepared material for study have resulted in major field studies and surveys in 8 countries in Central and South America, 8 Countries in tropical Africa, 2 countries in the Middle East, and 5 countries in Asia.

About the WRAIR/SI Collaboration »



The Walter Reed Biosystematics Unit | Museum Support Center, MRC-534 | Smithsonian Institution | 4210 Silver Hill Rd. | Suitland, MD 20746-2863 USA | Ph: 301-238-1077; FAX: 301-238-3168
Entomology Branch | Walter Reed Army Institute of Research | 503 Robert Grant Avenue | Silver Spring, MD 20910-7500 USA

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