Eastern equine encephalitis in 9 South American camelids.

Area of Science:

• Veterinary Neurology
• Infectious Diseases
• Alphavirus Research

Background:

• Eastern equine encephalitis (EEE) virus, a mosquito-borne alphavirus, is known to cause severe encephalitis in various mammals.
• EEE virus has not been previously reported in South American camelids.

Purpose of the Study:

• To investigate the occurrence and clinical presentation of EEE virus infection in South American camelids.
• To determine if South American camelids can naturally contract EEE virus and exhibit neurological signs.

Main Methods:

• A retrospective study of nine confirmed cases of EEE in camelids (8 alpacas, 1 llama) in the United States before 2006.
• Analysis of clinical signs, diagnostic test results (immunohistochemistry, PCR, serology), and neuropathology.

Main Results:

• Eight of nine (89%) camelids died or were euthanized within 2 days of diagnosis.
• Clinical signs included fever, lethargy, ataxia, seizures, and other signs consistent with severe encephalitis.
• Neuropathological findings revealed polioencephalitis with evidence of alphavirus infection in the central nervous system.

Conclusions:

• EEE virus should be considered a differential diagnosis for camelids presenting with central nervous system disease in endemic areas.
• Brain histopathology using immunohistochemistry or PCR is diagnostic for EEE in camelids.