Dreamcatcher Alpacas
Alpaca health · Infectious diseases

Eastern Equine Encephalitis (EEE) in Alpacas

Updated 2026-10-02By the Dreamcatcher Alpacas editorial team6 peer-reviewed references
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Emergency — call your vet now

This condition can kill within hours. Get veterinary help immediately.

A mosquito-borne viral brain infection reported in llamas and alpacas, mainly in the southeastern and Atlantic U.S.

Category
Infectious diseases
Urgency
Emergency

Signs & symptoms

  • Fever, depression
  • Incoordination, head pressing
  • Seizures and recumbency
  • Death

What causes it?

EEE virus transmitted by mosquitoes, with birds as reservoirs.

Risk factors

  • Swampy regions of the Atlantic and Gulf coasts and Great Lakes
  • Late summer mosquito season

How vets diagnose it

Blood antibody tests and brain testing at necropsy.

Treatment

Supportive vet care; prognosis is poor.

Do not wait to see if it improves. Camelids hide illness, and by the time signs are obvious the problem is often advanced. Call your veterinarian.

Prevention

  • Mosquito control: remove standing water, use fans at night
  • Ask your vet about extra-label use of equine EEE vaccines

Background

Eastern equine encephalitis (EEE), also called triple E and sleeping sickness, is a viral disease caused mainly by the Eastern equine encephalitis virus (EEEV). Most infections in humans are asymptomatic, but about 5% of the time the infection progresses to severe neuroinvasive disease. Symptoms typically appear 3–10 days after being bitten by an infected mosquito and initially include fever, headache, nausea, vomiting, fatigue, muscle pain, and joint pain. Neurological symptoms usually appear a few days later and include altered mental state, encephalitis, photophobia, seizures, paralysis, and loss of consciousness and coma. The case fatality rate is 30–75% depending on age, with disease severity greatest in young children and the elderly. About 50 to 90% of survivors experience long-term neurological complications that range from minor to severe. EEE is most common in horses, in which the disease carries a 70–90% case fatality rate and permanent brain damage for survivors.From Wikipedia — “Eastern equine encephalitis”, licensed under CC BY-SA 4.0.

Research & references

PubMed lists 5,889 peer-reviewed papers on this topic in camelids. The most relevant include:

  1. Camelid cardiology. Margiocco ML, Scansen BA, Bonagura JD The Veterinary clinics of North America. Food animal practice, 2009. PubMed 19460649 · DOI · cited 20×
  2. Llama dermatology. Rosychuk RA The Veterinary clinics of North America. Food animal practice, 1989. PubMed 2647233 · DOI · cited 12×
  3. Camelid wellness. Bennett MM, Richards NL The veterinary clinics of North America. Exotic animal practice, 2015. PubMed 25902272 · DOI · cited 3×
  4. Hematology of camelids. Vap L, Bohn AA The veterinary clinics of North America. Exotic animal practice, 2015. PubMed 25421025 · DOI · cited 15×
  5. Llama DNA Immunization and Isolation of Functional Single-Domain Antibody Binders. Trempe F, Rossotti MA, Maqbool T et al. Methods in molecular biology (Clifton, N.J.), 2022. PubMed 35157268 · DOI · cited 7×
  6. Update. Llama nutrition. Johnson LW The Veterinary clinics of North America. Food animal practice, 1994. PubMed 7953953 · DOI · cited 13×

Frequently asked questions

What is eastern Equine Encephalitis (EEE) in alpacas?
A mosquito-borne viral brain infection reported in llamas and alpacas, mainly in the southeastern and Atlantic U.S.
What are the signs of eastern Equine Encephalitis (EEE)?
Fever, depression, incoordination, head pressing, seizures and recumbency and death.
How do you prevent eastern Equine Encephalitis (EEE)?
Mosquito control: remove standing water, use fans at night. Ask your vet about extra-label use of equine EEE vaccines.
Is eastern Equine Encephalitis (EEE) an emergency?
Emergency — call your vet now. This condition can kill within hours. Get veterinary help immediately.

This page is educational and does not replace advice from a veterinarian who has examined your animals. Camelid medicine uses many drugs “extra-label”, so dosing must come from your vet. In an emergency, call your vet first. Read our disclaimer · How we write and review content.