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Postepizootic persistence of Venezuelan equine encephalitis virus, Venezuela.

Navarro JC, Medina G, Vasquez C, Coffey LL, Wang E, Suárez A, Biord H, Salas M, Weaver SC - Emerging Infect. Dis. (2005)

Bottom Line: Serologic evidence indicated that additional outbreaks occurred in Barinas State in 2003.Field studies identified known Culex (Melanoconion) spp. vectors and reservoir hosts of enzootic VEEV but a dearth of typical epidemic vectors.Cattle serosurveys indicated the recent circulation of enzootic VEEV strains, and possibly of epizootic strains.

View Article: PubMed Central - PubMed

Affiliation: Universidad Central de Venezuela, Caracas, Venezuela.

ABSTRACT
Five years after the apparent end of the major 1995 Venezuelan equine encephalitis (VEE) epizootic/epidemic, focal outbreaks of equine encephalitis occurred in Carabobo and Barinas States of western Venezuela. Virus isolates from horses in each location were nearly identical in sequence to 1995 isolates, which suggests natural persistence of subtype IC VEE virus (VEEV) strains in a genetically stable mode. Serologic evidence indicated that additional outbreaks occurred in Barinas State in 2003. Field studies identified known Culex (Melanoconion) spp. vectors and reservoir hosts of enzootic VEEV but a dearth of typical epidemic vectors. Cattle serosurveys indicated the recent circulation of enzootic VEEV strains, and possibly of epizootic strains. Persistence of VEEV subtype IC strains and infection of horses at the end of the rainy season suggest the possibility of an alternative, cryptic transmission cycle involving survival through the dry season of infected vectors or persistently infected vertebrates.

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Related in: MedlinePlus

Map of Venezuela showing locations of the 1995 Venezuelan equine encephalitis outbreak and the small outbreaks of 2000 and 2003, along with surveillance study sites.
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Figure 1: Map of Venezuela showing locations of the 1995 Venezuelan equine encephalitis outbreak and the small outbreaks of 2000 and 2003, along with surveillance study sites.

Mentions: The last major VEE epidemic began in April 1995 in the northern Venezuelan state of Falcon and spread throughout most of northern Venezuela and into La Guajira peninsula of northeastern Colombia to cause ≈75,000–100,000 human cases with ≈300 deaths (Figure 1) (4,5). Although the total number of equine cases was not reported, it was probably of a similar order of magnitude. The last equine and human cases were reported in December 1995 in Trujillo, Portuguesa, Cojedes, and Guarico States of Venezuela. After the apparent end of the 1995 outbreak, no confirmed epidemic or epizootic VEE occurred in South America for >4 years.


Postepizootic persistence of Venezuelan equine encephalitis virus, Venezuela.

Navarro JC, Medina G, Vasquez C, Coffey LL, Wang E, Suárez A, Biord H, Salas M, Weaver SC - Emerging Infect. Dis. (2005)

Map of Venezuela showing locations of the 1995 Venezuelan equine encephalitis outbreak and the small outbreaks of 2000 and 2003, along with surveillance study sites.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3367636&req=5

Figure 1: Map of Venezuela showing locations of the 1995 Venezuelan equine encephalitis outbreak and the small outbreaks of 2000 and 2003, along with surveillance study sites.
Mentions: The last major VEE epidemic began in April 1995 in the northern Venezuelan state of Falcon and spread throughout most of northern Venezuela and into La Guajira peninsula of northeastern Colombia to cause ≈75,000–100,000 human cases with ≈300 deaths (Figure 1) (4,5). Although the total number of equine cases was not reported, it was probably of a similar order of magnitude. The last equine and human cases were reported in December 1995 in Trujillo, Portuguesa, Cojedes, and Guarico States of Venezuela. After the apparent end of the 1995 outbreak, no confirmed epidemic or epizootic VEE occurred in South America for >4 years.

Bottom Line: Serologic evidence indicated that additional outbreaks occurred in Barinas State in 2003.Field studies identified known Culex (Melanoconion) spp. vectors and reservoir hosts of enzootic VEEV but a dearth of typical epidemic vectors.Cattle serosurveys indicated the recent circulation of enzootic VEEV strains, and possibly of epizootic strains.

View Article: PubMed Central - PubMed

Affiliation: Universidad Central de Venezuela, Caracas, Venezuela.

ABSTRACT
Five years after the apparent end of the major 1995 Venezuelan equine encephalitis (VEE) epizootic/epidemic, focal outbreaks of equine encephalitis occurred in Carabobo and Barinas States of western Venezuela. Virus isolates from horses in each location were nearly identical in sequence to 1995 isolates, which suggests natural persistence of subtype IC VEE virus (VEEV) strains in a genetically stable mode. Serologic evidence indicated that additional outbreaks occurred in Barinas State in 2003. Field studies identified known Culex (Melanoconion) spp. vectors and reservoir hosts of enzootic VEEV but a dearth of typical epidemic vectors. Cattle serosurveys indicated the recent circulation of enzootic VEEV strains, and possibly of epizootic strains. Persistence of VEEV subtype IC strains and infection of horses at the end of the rainy season suggest the possibility of an alternative, cryptic transmission cycle involving survival through the dry season of infected vectors or persistently infected vertebrates.

Show MeSH
Related in: MedlinePlus