RESUMO

Two virus isolates, 1 each from Aedes campestris and Psorophora signipennis mosquitoes collected in south central New Mexico in August 1985, were shown by neutralization tests to be identical to each other, but not to any of more than 250 arthropod-borne and other viruses. Electron microscopy of 1 isolate (85-488NM, chosen as the prototype) indicated that this strain shares morphologic characteristics with viruses of the family Rhabdoviridae. Indirect fluorescent antibody tests indicated that this virus is a member of the genus Vesiculovirus, but is not closely related to any of the North American or other rhabdoviruses with which it was tested, including vesicular stomatitis (Indiana) and vesicular stomatitis (New Jersey) viruses. The name Malpais Spring virus is proposed for this newly recognized vesiculovirus. A serologic survey indicated that Malpais Spring virus infects indigenous (mule deer and pronghorn) and exotic (gemsbok) ungulates at and near the sites where the mosquitoes from which the virus strains were isolated were collected. Antibody prevalence in wild animals indicates that the pronghorn and gemsbok may play roles as hosts for Malpais Spring, epizootic hemorrhagic disease (New Jersey), and bluetongue viruses in this area.

Assuntos

RESUMO

An arbovirus survey was conducted during August 1985 at White Sands Missile Range in southcentral New Mexico following a suspected arboviral disease epizootic among feral horses. A total of 20,566 mosquitoes (18,505 females and 2,061 males) and 8,900 biting gnats were collected and assayed for virus. Female mosquitoes were principally Aedes campestris (54.8%), Aedes dorsalis (30.4%) and Culex tarsalis (13.2%). Arboviruses were not isolated from biting gnats, but mosquitoes yielded a total of 37 viral isolates, including western equine encephalitis (WEE) (18), California serogroup (15), Cache Valey (1), and Hart Park (1) viruses in addition to 2, as yet unidentified, rhabdoviruses. Isolates of WEE virus were from 9 pools of Ae. campestris, 6 of Cx. tarsalis and 3 of Ae. dorsalis. California serogroup viruses, including 2 subtypes, were obtained from 7 pools of females and 1 pool of males of Ae. campestris and from 4 pools of Ae. dorsalis. Cache Valley and Hart Park viruses were isolated from single pools of Ae. dorsalis and Cx. tarsalis, respectively, and the rhabdoviruses were obtained from Ae. campestris and Psorophora signipennis.

Assuntos

Assuntos

RESUMO

Polyriboinosinic.polyribocytidylic acid [poly(I).poly(C)] stabilized with poly-l-lysine and carboxymethylcellulose [poly(ICLC)] has been previously shown to be a compound with marked adjuvant activity when given in high doses with inactivated Venezuelan equine encephalomyelitis (VEE) virus vaccine. This study investigated the effects of much lower doses of poly(ICLC) on the magnitude and kinetics of the primary and secondary humoral antibody responses of rhesus monkeys to inactivated VEE virus vaccine. Monkeys given a single injection of vaccine developed very low neutralizing antibody titers, whereas those given adjuvant plus vaccine had 30- to 100-fold-higher titers which remained elevated for longer than 6 months. Low doses of poly(ICLC) given with VEE virus vaccine resulted in a profound but transient increase in priming of secondary antibody responses to the antigen. In contrast, the administration of poly-l-lysine and carboxymethylcellulose alone without the poly(I).poly(C) component of the complex had no adjuvant effect on antibody responses of monkeys to VEE virus vaccine. The temporal development of antibody by class (immunoglobulin M-immunoglobulin G) in monkeys given two injections of adjuvant-vaccine was not different from that with vaccine alone. Serial hematological and clinical chemistry determinations on monkeys given single or multiple doses of poly(ICLC) with vaccine were not different from values in monkeys given vaccine alone.

Assuntos

RESUMO

Complexes of formalinized Venezuelan equine encephalomyelitis (VEE) virus vaccine and specific IgG formed at antigen-antibody equivalence enhanced the immune responses of rhesus monkeys (Macaca mulatta). The predomonant class of antibody elicited by complexes was IgG. In contrast, lower titers of antibody and a more biphasic (IgG-IgM) response were observed after exposure of monkeys to the vaccine alone. In comparison to the response of monkeys primed with antigen, a more rapid secondary response was obtained in monkeys primed with the complexes of antigen and antibody formed at equivalence. A sustained level of protection of 88% was afforded mice 24 hr after immunization with antigen-antibody complexes; development of protection after administration of antigen required eight days to reach this level. Passive protection (80%-100%) was conferred by IgG controls for seven to eight days after immunization. This level of protection was not significantly affected by X-irradiation 24 hr prior to administration of IgG; however, protection in mice similarly irradiated prior to immunization with antigen-antibody complexes was significantly decreased. Early protection afforded by the complexes was not nonspecific (interferon) but was mediated by specific immunologic mechanisms and may be caused by an early formation of IgG.

Assuntos

RESUMO

Transplacental infection of mouse fetuses with Venezuelan equine encephalomyelitis was produced by intraperitoneal injection of dams at various stages of gestation with 10(3) suckling mouse intracerebral median lethal doses of an attenuated strain (TC-83). Virus inoculation, at times ranging from 6 days prior to mating to 9 days after conception, had no effect on conception rate, litter size, or survival of the newborn. Inoculation of the dam from the 10th to 13th days of gestation resulted in decreased litter size, an increase in stillbirths, and a decrease in birth-to-weaning survival. Inoculation of the dams later in gestation only decreased the birth-to-weaning survival. No evidence of morphologic abnormality was noted in any of the newborn.

Assuntos