Ecologic Studies of Venezuelan Encephalitis Virus in Southeastern Mexico

Scherer, William F.; Campillo_Sáinz, Carlos; Mucha-macías, J. De; Dickerman, Robert W.; Chía, C. Wong; Zárate, M. L.

doi:10.4269/ajtmh.1972.21.79

Cited by 20 publications

(15 citation statements)

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“…38 Other mammals, such as opossums (Didelphis marsupialis) are also frequently infected with enzootic VEE viruses in a variety of locations. 30,31,[39][40][41] The high rate of VEE virus antibodies we found in Proechimys guairae is consistent with the conclusions of previous studies that these spiny rats are important reservoir hosts of enzootic VEE viruses. 37 We also detected antibodies in two Didelphis marsupialis, consistent with previous results in Venezuela.…”

Section: Discussionsupporting

confidence: 80%

See 1 more Smart Citation

Ecological studies of enzootic Venezuelan equine encephalitis in north-central Venezuela, 1997-1998.

Salas¹,

García

Liria

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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Abstract. From 1997From -1998, we investigated the possible continuous circulation of epizootic Venezuelan equine encephalitis (VEE) virus suggested by a 1983 subtype IC interepizootic mosquito isolate made in Panaquire, Miranda State, Venezuela. The study area was originally covered by lowland tropical rainforest but has been converted into cacao plantations. Sentinel hamsters, small mammal trapping, mosquito collections, and human serosurveys were used to detect active or recent virus circulation. Six strains of subtype ID VEE virus were isolated from hamsters that displayed no apparent disease. Four other arboviruses belonging to group A (Togaviridae: Alphavirus), two Bunyamwera group (Bunyaviridae), and three Gamboa group (Bunyaviridae) arboviruses were also isolated from hamsters, as well as 8 unidentified viruses. Venezuelan equine encephalitis-specific antibodies were detected in 5 small mammal species: Proechimys guairae, Marmosa spp., and Didelphis marsupialis. Mosquito collections comprised of 38 different species, including 8 members of the subgenus Culex (Melanoconion), did not yield any virus isolates. Sera from 195 humans, either workers in the cacao plantation or nearby residents, were all negative for VEE virus antibodies. Sequences of 1,677 nucleotides from the P62 gene of 2 virus isolates indicated that they represent a subtype ID lineage that is distinct from all others characterized previously, and are unrelated to epizootic VEE emergence.

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Section: Discussionsupporting

confidence: 80%

“…In previous studies with subtype IE VEE viruses, experimentally infected Didelphis marsupialis generated viremia of up to 10 4.5 suckling mouse intracerebral LD 50 /ml. 39 Experimental infections are needed to determine if Didelphis marsupialis, and Marmosa spp. produce adequate viremia to be important reservoir hosts of subtype ID viruses.…”

Section: Discussionmentioning

confidence: 99%

Ecological studies of enzootic Venezuelan equine encephalitis in north-central Venezuela, 1997-1998.

Salas¹,

García

Liria

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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“…Therefore, a better understanding of VEEV ecology in Mexico is essential for assessing the risk for widespread disease. Our results support the conclusions of Scherer et al (6) that VEEV has a wide range of mammalian hosts that may participate in the natural transmission cycle. This strategy may be an adaptive one that affords greater population stability than does specialization for 1 amplifying host species.…”

Section: Genus Oligoryzomyssupporting

confidence: 82%

“…These viruses are thought to circulate continuously among mosquitoes and their principal vertebrate amplifying hosts, whereas horses and humans are considered spillover, dead-end hosts not required for maintenance of the natural cycle. Several studies have shown that terrestrial mammals of 5 genera (Didelphis, Oryzomys, Proechimys, Sigmodon, and Zygodontomys) are susceptible to VEEV-IE infection; they develop viremia suffi cient to infect mosquito vectors, yet they usually survive infection (5)(6)(7)(8)(9)(10).…”

mentioning

confidence: 99%

Experimental Infection of Potential Reservoir Hosts with Venezuelan Equine Encephalitis Virus, Mexico

Deardorff¹,

Forrester²,

Rosa³

et al. 2009

Emerg. Infect. Dis.

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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 amplifi cation outside the disease-endemic range.

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“…Currently, no vaccine for VEEV is publicly available and the experimental military vaccine has poor efficacy (Colpitts et al 2007;Russell 1999). In nature, VEEV is maintained in a cycle between mosquitoes and small rodents (Grayson and Galindo 1968;Nalca et al 2003;Scherer et al 1972). Epidemic outbreaks of the epizootic strains occur in 10-20-year intervals in the ranch areas in Peru, Venezuela, Colombia and Ecuador after heavy rainfall, which lead to increased mosquito populations (Rivas et al 1997).…”

Section: Togaviridaementioning

confidence: 99%