PubMed Health⌕ Search

Biomedical subjects

J McLintock

Publications and source records attributed to J McLintock.

15 recordsLinked to original sources
PubMed1978

Intranasal exposure of the Richardson's ground squirrel to Western equine encephalomyelitis virus.

Adult Richardson's ground squirrels were infected with western equine encephalomyelitis virus by intranasal instillation. Mortality followed the instillation of a minimum threshold of 4.7 logs of virus while infection was produced by a dosage of 2.3 logs. The incubation period was from four to seven days, being preceded by a viremic phase. Signs were depression, ataxia and paralysis of the limbs. Highest titres of virus were recovered from the brain and histopathological changes involving the central nervous system included meningitis, vasculitis, perivascular cuffing, gliosis, neuronophagia and neuronal degeneration. The virus was also found in a variety of extraneural tissues. Lesions in extraneural tissues included necrosis of brown fat and an apparent increase in number of Kupffer's cells in the liver. The lymphoid tissue was involved indicating a possible source for viremia. The duration and magnitude of viremia were ample enough to provide virus source for arthropods. The potential for transmission of the virus independent of arthropods was discussed in view of the pathogenesis demonstrated in the experimental infections.

Animals↗
PubMed1976

Subcutaneous exposure of the Richardson's ground squirrel (Spermophilus richardsonii Sabine) to western equine encephalomyelitis virus.

Both adult and suckling Richardson's ground squirrels (Spermophilus richardsonii) were susceptible to subcutaneous exposure with western equine encephalomyelitis (WEE) virus, but the virus was more virulent for sucklings than adults. In sucklings, the incubation period was from 4 to 5 days, followed by apparent signs of central nervous system (CNS) involvement. Death occurred 10 to 13 days postexposure. In adults, infections were inapparent or acute with typical signs of CNS involvement similar to those observed in sucklings. In both age groups, brain and lymph nodes were the most frequently involved tissues. The highest titres of virus were recovered from brain, sections of which also showed the most marked histological changes. Lesions in the brain included multifocal vasculitis, perivascular edema, perivascular cuffing, focal or diffuse gliosis, parenchymal hemorrhage, meningitis with infiltration of mononuclear cells, neuronal degeneration, and occasional demyelination. For both age groups, viremias were detected for 3 to 5 days with a maximum virus titre of 4 to 6 logs, a sufficient time and magnitude to infect numerous mosquitoes, further supporting the hypothesis that S. richardsonii may serve as an amplifying host of WEE virus in the prairie provinces.

Animals↗
PubMed1972

Laboratory studies on the transmission of western equine encephalitis virus by Saskatchewan mosquitoes. I. Culex tarsalis.

A Saskatchewan strain of the mosquito Culex tarsalis, transmitted a local strain of western equine encephalitis virus from chick to chick, between four and 44 days after an infective blood meal. At incubation temperatures of 69 and 75 degrees F, 120 transmissions occurred out of a possible 141, and all but seven of these were by single infected mosquitoes. At 75 degrees F virus titers in individual mosquitoes were more uniform and transmission was more efficient, than at 69 degrees F, although infection rates were similar at both temperatures. The minimum concentration of virus required to infect 50% of C.tarsalis was 10(2.5) intracerebral three-week old mouse LD(50) per 0.03 ml of donor blood. These findings provide direct evidence that C. tarsalis of Saskatchewan is a highly efficient vector of western equine encephalitis virus.

Animals↗
PubMed1966

Western equine encephalitis virus in Saskatchewan garter snakes and leopard frogs.

Western equine encephalitis virus was isolated from two naturally infected snakes on first bleeding and from seven others at subsequent bleedings, both with and without preliminary chilling. One snake, with neither detectable virus nor serum neutralizing antibodies when first bled, developed viremia later. Viremia in garter snakes has a cyclic rhythm independent of the temperature of the environment. Virus was isolated from 6 frogs, and 50 out of 179 had detectable serum neutralizing antibodies. Infections with this virus are widely distributed in garter snakes and leopard frogs in the agricultural area of Saskatchewan.

Animals↗