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Miscellaneous mosquito-borne diseases

Last updated: August 26, 2024

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Mosquito-borne diseases are a group of viral infections transmitted by the bite of an infected mosquito, typically from the Culex, Anopheles, or Aedes species. Vertical and human-to-human transmission (e.g., via blood transfusions, organ, and tissue transplants) are also possible. These viral diseases belong to three main families: Togaviridae (Chikungunya virus, Eastern equine encephalitis (EEEV), Western equine encephalitis (WEEV), Flaviviridae (West Nile virus, Dengue virus, Zika virus, Yellow fever virus, Japanese encephalitis virus), and Bunyaviridae (Rift Valley fever virus, La Crosse encephalitis virus). Clinical features of these diseases vary but often include an initial systemic febrile illness (i.e., fever, headache, myalgias, gastrointestinal symptoms) that progresses to a neuroinvasive disease (e.g., meningitis, encephalitis). Diagnosis is made via antibody detection (e.g., IgM, IgG), ELISA, FIA, or PCR. Treatment is typically supportive. Prevention primarily consists of mosquito control measures (i.e., adequate clothing, insect repellents, mosquito nets, minimizing mosquito breeding).

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Mosquito-borne Togavirus diseasestoggle arrow icon

Overview

Overview of mosquito-borne Togavirus diseases
Geography Incubation period Clinical features CSF analysis
Chikungunya fever
  • Found primarily in tropical and subtropical regions (e.g., Central and South America, Caribbean, sub-Saharan Africa, Southern and Western Asia, and Europe) [1]
  • 3–7 days
  • Normal
Eastern equine encephalitis (EEE)
  • Found primarily in the Americas
  • In the US, occurs east of the Mississippi River (e.g., New York, New Jersey, Michigan)
  • 4–10 days
Western equine encephalitis (WEE)
  • Occurs on the West Coast of the United States and Canada
  • 2–7 days
Venezuelan equine encephalitis (VEE)
  • Found predominantly in the Americas (Colombia, Venezuela, Panama, Guatemala, Mexico, the United States, Ecuador, Nicaragua, Costa Rica, Peru)
  • 2–5 days
Ross River fever (RRF)
  • Found predominantly in Australia, Papua New Guinea, the Solomon Islands, and other parts of Southeast Asia
  • 3–9 days
  • Normal

Barmah Forest virus disease

  • Found in Australia and Papua New Guinea
  • 7–10 days

Chikungunya fever [2][3]

Consider Chikungunya virus infection in patients with sudden onset of fever and polyarthralgia who have recently traveled to regions where the virus is present. [2]

Hemorrhagic complications are uncommon and should prompt consideration of alternative diagnosis, e.g. dengue.

Avoid NSAIDs (e.g., aspirin) until dengue has been ruled out to prevent bleeding. [3]

Eastern equine encephalitis (EEE)

Western equine encephalitis (WEE)

Venezuelan equine encephalitis (VEE)

Ross River fever (RRF)

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Mosquito-borne Flavivirus diseasestoggle arrow icon

Overview of mosquito-borne Flavivirus diseases
West Nile virus fever Murray Valley encephalitis (MVE) St. Louis encephalitis
Epidemiology
  • One of the most widely distributed arboviruses
  • Endemic in Africa, parts of Europe, South Asia, Australia, the United States, and the Middle East
  • Outbreaks during summer and fall
  • Found in Australia, Papua New Guinea, and Indonesia
  • Sporadic outbreaks
  • Found in North, Central, and South America
  • Outbreaks during summer

Etiology

Pathogen
Vectors
  • Mosquitoes (Culex, Aedes, or Anopheles spp.)
  • Mosquitoes (Culex spp.)
  • Mosquitoes (Culex spp.)
Reservoirs
  • Mosquitoes, birds, horses, dogs
  • Mosquitoes, birds
  • Mosquitoes, birds
Route of transmission
  • Mosquito bite
  • Human-to-human
  • Mosquito bite
  • Mosquito bite
Incubation period
  • 2–14 days [12]
  • 1–4 weeks [13]
  • 4–21 days [14]
Clinical features
Diagnostics Laboratory studies
Confirmatory tests
Lumbar puncture (CSF analysis)
Brain MRI
  • Normal or demonstrates nonspecific changes (increased signal intensity)
  • Normal or demonstrates nonspecific changes
Other
  • Viral culture
  • EEG: shows slow delta wave activity
  • Viral culture
Differential diagnosis
Treatment
Complications
  • Permanent neurological deficits (∼ 50% of symptomatic individuals) [16]
  • Death (∼ 33% of patients with neurological symptoms) [16]

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Mosquito-borne Bunyavirus diseasestoggle arrow icon

Overview of mosquito-borne Bunyavirus diseases
La Crosse encephalitis Rift Valley fever
Epidemiology
  • Found in the midwestern, central, and southeastern parts of the United States
  • Common in children (1–15 years of age) [17]
  • Outbreaks during the summer
  • Found in Egypt, Sub-Saharan Africa, and the Arabian Peninsula
  • Sporadic outbreaks
Etiology Pathogen
Vectors
  • Mosquito: Aedes triseriatus (tree hole mosquito)
  • Mosquito (Aedes and Culex spp.)
Reservoirs
  • Chipmunks, foxes, squirrels, woodchucks
  • Cattle, sheep, goats, camels
Route of transmission
  • Mosquito bite
  • Mosquito bite
  • Direct contact with blood or tissues of infected animals
  • Inhalation of aerosols from infected animal tissue
Incubation period
  • 5–15 days [17]
  • 2–6 days [18]
Clinical features
  • Most affected individuals are asymptomatic.
Diagnostics Laboratory studies
Confirmatory tests
Lumbar puncture
Other
  • EEG: shows slowing, epileptiform discharges
  • Viral culture
Differential diagnosis
Treatment
Complications
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Preventiontoggle arrow icon

Mosquito bite prevention

  • Clothing
    • Wear light-colored clothing.
    • Long-sleeved shirts and long pants
  • Insect repellent
    • Use insect repellants (e.g., DEET, permethrin, oil of lemon eucalyptus)
    • Apply to clothing and footwear.
  • Mosquito nets
    • Place screens at doors and windows.
    • Use mosquito nets on baby strollers, carriers, and cribs.
  • Remove open water containers, trash containers, and water-holding plants to minimize mosquito breeding.

Obligation to report

  • Mosquito-borne diseases are nationally notifiable diseases in most countries worldwide (i.e., the physician is required by law to report cases of such diseases).
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