Experimental Infection of Horses with Enzootic and Epizootic Strains of Venezuelan Equine Encephalomyelitis Virus

Walton, T. E.; Alvarez, Otto; Buckwalter, Ross M.; Johnson, Karl M.

doi:10.1093/infdis/128.3.271

Cited by 93 publications

(94 citation statements)

References 22 publications

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“…The vaccine was originally developed for use in humans at risk for VEE virus infections. In horses, the vaccine induces long lasting neutralising antibodies [27,98] and it was proven to be very efficacious in controlling the epidemics of VEE in Central America in the early nineteen-seventies [26,97]. However, several biosafety issues are associated with the use of this vaccine.…”

Section: Current Vaccinesmentioning

confidence: 99%

Equine viral vaccines: the past, present and future

2004

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-The increasing international movement of horses combined with the relaxation of veterinary regulations has resulted in an increased incidence of equine infectious diseases. Vaccination, along with management measures, has become the primary method for the effective control of these diseases. Traditionally modified live and inactivated vaccines have been used and these vaccines have proven to be very successful in preventing disease. However, there are a number of equine infectious diseases for which conventional technology has shown its limitations. The advent of recombinant technology has stimulated the development of second generation vaccines, including gene deleted mutants, live vectored vaccines and DNA vaccines. These vaccines have in common that protective antigens are endogenously processed and presented along the molecules of the MHC I and MHC II complex, resulting in the stimulation of both humoral and cell-mediated immune responses similar to natural infection. The present paper provides a review of the vaccines being employed today against the most important equine viral diseases followed by a summary of new developments that are expected to bring improved vaccines to the market in the foreseeable future.

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Section: Current Vaccinesmentioning

confidence: 99%

Equine viral vaccines: the past, present and future

2004

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“…However, severe neurological infection, including fatal encephalitis, is common in infections of rodents [2,3] and horses [4], and can occur in humans, typically children [5]. Although natural disease is usually acquired through mosquito bite, VEEV is highly infectious as an aerosol and has caused many laboratory infections by this route [6].…”

Section: Introductionmentioning

confidence: 99%

Genetically engineered, live attenuated vaccines for Venezuelan equine encephalitis: testing in animal models

Pratt

Davis

Johnston

et al. 2003

Vaccine

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“…mosquitoes among rodent reservoir hosts (1) and (ii) epidemic͞epizootic viruses (usually subtypes IAB and IC) (1,2), which emerge periodically to cause outbreaks involving up to hundreds of thousands of humans and horses (4)(5)(6)(7). Epizootic subtype IAB and IC viruses use equines as amplification hosts and develop much higher viremia titers in horses than enzootic strains, which are generally incapable of sufficient levels of equine amplification to cause outbreaks (8,9). Several different mosquito species, some of which are only marginally susceptible to infection, have been implicated as vectors during epizootics when their large population sizes allow for efficient transmission (1, 10, 11).…”

mentioning

confidence: 99%

Venezuelan equine encephalitis emergence: Enhanced vector infection from a single amino acid substitution in the envelope glycoprotein

Brault¹,

Powers²,

Ortiz³

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

160

137

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In 1993 and 1996, subtype IE Venezuelan equine encephalitis (VEE) virus caused epizootics in the Mexican states of Chiapas and Oaxaca. Previously, only subtype IAB and IC VEE virus strains had been associated with major outbreaks of equine and human disease. The IAB and IC epizootics are believed to emerge via adaptation of enzootic (sylvatic, equine-avirulent) strains for high titer equine viremia that results in efficient infection of mosquito vectors. However, experimental equine infections with subtype IE equine isolates from the Mexican outbreaks demonstrated neurovirulence but little viremia, inconsistent with typical VEE emergence mechanisms. Therefore, we hypothesized that changes in the mosquito vector host range might have contributed to the Mexican emergence. To test this hypothesis, we evaluated the susceptibility of the most abundant mosquito in the deforested Pacific coastal locations of the VEE outbreaks and a proven epizootic vector, Ochlerotatus taeniorhynchus. The Mexican epizootic equine isolates exhibited significantly greater infectivity compared with closely related enzootic strains, supporting the hypothesis that adaptation to an efficient epizootic vector contributed to disease emergence. Reverse genetic studies implicated a Ser 3 Asn substitution in the E2 envelope glycoprotein as the major determinant of the increased vector infectivity phenotype. Our findings underscore the capacity of RNA viruses to alter their vector host range through minor genetic changes, resulting in the potential for disease emergence.

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Experimental Infection of Horses with Enzootic and Epizootic Strains of Venezuelan Equine Encephalomyelitis Virus

Cited by 93 publications

References 22 publications

Equine viral vaccines: the past, present and future

Equine viral vaccines: the past, present and future

Genetically engineered, live attenuated vaccines for Venezuelan equine encephalitis: testing in animal models

Venezuelan equine encephalitis emergence: Enhanced vector infection from a single amino acid substitution in the envelope glycoprotein

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