A Comparative Study of Virulences, Plaque Morphologies and Antigenic Characteristics of Venezuelan Encephalitis Virus Strains1

Venezuelan Equine Encephalitis Virus Infection of Cotton Rats

“…This difference in disease and survival was more pronounced than that reported in other studies of VEEV-reservoir host interactions, some of which suggested that cotton rats die because of experimental manipulations or anesthesia rather than from a viral cause ( 19 – 21 , 24 ). Our results indicate that VEEV was the cause of death for most or all of our rats, and signs of encephalitis were consistent with those described in VEEV-infected mice or guinea pigs ( 8 , 33 , 34 ).…”

“…However, spiny rats ( Proechimys spp., family Echimyidae ) and cotton rats ( Sigmodon spp., family Cricetidae) have been most often implicated as principal reservoir hosts for enzootic strains, based on seroprevalence and experimental infections demonstrating viremia adequate in titer and duration to infect enzootic mosquito vectors ( 19 – 22 ). Their geographic distributions are different, but overlapping: Proechimys spp.…”

“…Studies supporting the role of cotton rats as reservoir hosts for enzootic VEEV have investigated viremia and antibody responses as well as horizontal transmission in laboratory settings ( 19 – 21 , 24 , 25 ). Howard et al reported illness and death in cotton rats after infection with a Texas epizootic subtype IB strain ( 21 ).…”

Experimental Everglades Virus Infection of Cotton Rats (Sigmodon hispidus)

“…Golden Syrian hamsters and Swiss albino mice experience 75%–100% mortality with doses as low as 3 log 10 Vero PFU, and pathologic lesions develop, consistent with VEE-like disease ( 14 , 30 , 37 , 38 ). Even though infection of laboratory rodents often causes death, EVEV infection is less virulent than most other VEE complex viruses, which generally cause 100% of infected animals to die ( 14 , 30 , 31 , 38 ). …”

Venezuelan Equine Encephalomyelitis Virus (VEEV): Strain Differentiation and Specification of Virulence Markers

“…Comparative studies with strains ofVEEV (Zarate & Scherer, 1969;Zarate, I972;Dickerman, 1972 ) and Semliki Forest virus (Bradish,Allner & Maber,I97I;Bradish & Allner,I972) have suggested that the appropriate measurement of the responses of different hosts to infection by various doses of virus may form the basis of a virulence-marker system through which serologically identical strains of virus may be distinguished and their immunogenic, protective or lethal potentials characterized.…”