Eastern and Western Equine Encephalitis

• Single-stranded enveloped RNA viruses belong to the Togaviridae family.

Eastern Equine Encephalitis (EEE)

• Common in the eastern U.S. and the Midwest.
• Clinical Symptoms:
  • Febrile illness with fever, headache, nausea, and vomiting.
  • Neurological symptoms, including cranial nerve palsy, seizures, and coma.
  • Encephalitis, which can lead to cerebral edema, coma, brain damage, and death.
• Prevention involves vaccines, insect repellents, protective clothing, and vector control.
• Horses and birds serve as reservoirs that transmit the virus to mosquitoes.
• Culex mosquitoes transmit the virus to humans.
• Diagnosis involves MRI to observe lesions in the basal ganglia and thalamus, as well as antibody detection in the blood.
• Treatment includes supportive care, anticonvulsants, and corticosteroids.

Western Equine Encephalitis (WEE)

• Common in the western United States and Canada.
• Prevention involves vaccines, insect repellents, protective clothing, and vector control.

Venezuelan Equine Encephalitis (VEE)

• Found in South and Central America, and the southern U.S.
• Prevention involves vaccines, insect repellents, protective clothing, and vector control.

Chikungunya Fever

• A mosquito-borne viral disease.
• Transmitted by Aedes mosquitoes (Aedes albopictus and Aedes aegypti).
• Peak biting times are early morning and late afternoon.
• These mosquitoes also transmit Dengue, Yellow fever, and Zika virus.
• Aedes aegypti also bites indoors.
• Outbreaks are common after rainy seasons due to increased mosquito populations.
• Symptoms include sudden high fever (above 102°F, sometimes reaching 104°F), joint pain (87-98% of cases), rash, headache, muscle pain, fatigue, joint swelling, nausea, vomiting, or diarrhea.
• Joint pain can persist for weeks, months, or years.
• Potential complications include heart failure, pancreatitis, myocarditis, pericarditis, renal failure, hepatitis, and pneumonia.
• People over 45 years old are more susceptible.
• First reported in Africa, Asia, and islands in the Indian and Pacific Oceans, with the first case in the Americas reported in the Caribbean.
• More common in Sub-Saharan Africa, Southeast Asia, and the Indian subcontinent.
• Rare transmission routes include mother to newborn during birth and potential spread through blood transfusion.
• No specific antiviral treatment exists; care involves rest, fluids, and acetaminophen or ibuprofen for symptom relief.
• Prevention involves avoiding mosquito bites, wearing protective clothing, staying indoors with air conditioning or screened areas, using mosquito repellent (DEET-based), and eliminating standing water.
• Diagnosis involves excluding other conditions with similar symptoms and serological tests (ELISA to detect IgM and IgG antibodies).
• IgM persists for about two months, and viral isolation can be used.
• Risk factors for severe disease include heart disease, respiratory disease, hypertension, and diabetes.
• Monkeys act as reservoirs.