Experimental infection of potential reservoir hosts with Venezuelan equine encephalitis virus, Mexico

• Published in: Emerging infectious diseases Vol. 15; no. 4; pp. 519 - 525
• Main Authors: Deardorff, Eleanor R, Forrester, Naomi L, Travassos-da-Rosa, Amelia P, Estrada-Franco, Jose G, Navarro-Lopez, Roberto, Tesh, Robert B, Weaver, Scott C
• Format: Journal Article
• Language: English
• Published: United States U.S. National Center for Infectious Diseases 01.04.2009; Centers for Disease Control and Prevention
• Subjects: alphaviruses; Animals; Animals, Wild - virology; Baiomys; bioterrorism agents and preparedness; Causes of; Communicable Diseases, Emerging - epidemiology; Communicable Diseases, Emerging - transmission; Communicable Diseases, Emerging - veterinary; Communicable Diseases, Emerging - virology; Diagnosis; Disease Outbreaks - veterinary; Disease Reservoirs - veterinary; Disease Reservoirs - virology; Distribution; Ecosystem; Encephalitis Virus, Venezuelan Equine - pathogenicity; encephalomyelitis virus; Encephalomyelitis, Venezuelan Equine - epidemiology; Encephalomyelitis, Venezuelan Equine - transmission; Encephalomyelitis, Venezuelan Equine - veterinary; Encephalomyelitis, Venezuelan Equine - virology; Epidemiology; Equine encephalomyelitis; Horse Diseases - epidemiology; Horse Diseases - transmission; Horse Diseases - virology; Horses; Liomys; Mexico - epidemiology; Musculus; Oryzomys couesi; Rodentia - virology; Sigmodon hispidus; transmission; vector-borne infections; Venezuelan equine encephalitis virus; Viremia - immunology; Viremia - veterinary; Zoonoses; Mexico; ISE, Mexico, Chiapas
• ISSN: 1080-6040; 1080-6059
• DOI: 10.3201/eid1504.081008

In 1993, an outbreak of encephalitis among 125 affected equids in coastal Chiapas, Mexico, resulted in a 50% case-fatality rate. The outbreak was attributed to Venezuelan equine encephalitis virus (VEEV) subtype IE, not previously associated with equine disease and death. To better understand the ecology of this VEEV strain in Chiapas, we experimentally infected 5 species of wild rodents and evaluated their competence as reservoir and amplifying hosts. Rodents from 1 species (Baiomys musculus) showed signs of disease and died by day 8 postinoculation. Rodents from the 4 other species (Liomys salvini, Oligoryzomys fulvescens, Oryzomys couesi, and Sigmodon hispidus) became viremic but survived and developed neutralizing antibodies, indicating that multiple species may contribute to VEEV maintenance. By infecting numerous rodent species and producing adequate viremia, VEEV may increase its chances of long-term persistence in nature and could increase risk for establishment in disease-endemic areas and amplification outside the disease-endemic range.