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Biomedical subjects

D M McLean

Publications and source records attributed to D M McLean.

At least 37 records · Page 2Linked to original sources
PubMed1977

California encephalitis virus transmission by arctic and domestic mosquitoes.

A zero passage arctic mosquito isolate of California encephalitis (CE) virus (showshoe hare subtype) was transmitted by wild-caught Aedes communis mosquitoes after 13 days incubation at 13 degrees and 23 degrees C, AFTER 20 days incubation at 13 degrees C, when mosquitoes imbibed 1 mouse LD50 in a blood meal. Transmission occurred after 20 days incubation at 13 degrees and 23 degrees C when mosquitoes were injected intrathoracially with 1 or 0.1 mouse LD50. Virus was also transmitted by A. aegypti 13 days after infection with 100 mouse LD50 by feeding or intrathoracic injection, and incubation at 13 degrees C. Virus antigen was detected in salivary glands of 42 percent virus-positive A communis mosquitoes by direct immunofluorescence, and in 50 percent or less of A aegypti mosquitoes by immunoperoxidase and immunofluorescence, with somewhat greater regularity by the indirect than the direct technique.

Aedes↗
PubMed1977

Bunyavirus isolations from mosquitoes in the western Canadian Arctic.

Strains of California encephalitis virus (snowshoe hare subtype) were isolated from 8 of 475 pools comprising 23 747 unengorged female mosquitoes of five species collected at three of six locations throughout the Mackenzie Valley of the Northwest Territories, Canada, from latitudes 60 to 69 degrees N between 10 and 24 July 1976. Minimum field infection rates included 1:2734 for Aedes communis, 1:256 to 1:3662 for A. hexodontus and 1:911 to 1:1611 for A. punctor. Northway virus was also isolated from 1 of 3662 A. hexodontus mosquitoes collected at Inuvik (69 degrees N, 135 degrees W). Transmission of CE virus by A. communis infected by feeding on virus in defibrinated blood and incubation at 0, 13 and 23 degrees C for 13-20 days clearly demonstrates the importance of this species as a natural vector, and transmission of CE virus by Culiseta inornata after incubation at 0 and 13 degrees C following intrathoracic injection strengthens evidence of its role as a natural vector. Immunofluorescence was less reliable than imunoperoxidase for detection of CE viral antigen in mosquito salivary glands.

Aedes↗
PubMed1976

California encephalitis virus proliferation in Yukon mosquitoes incubated at low temperatures.

Replication of a subarctic Bunyavirus, California encephalitis (snowshoe hare subtype), was detected in salivary glands and thoraces of wild-caught Aedes communis mosquitoes from the Yokon Territory, after intrathoracic inoculation with 0.1 to 100 mouse LD50 virus, and incubation for 7 to 21 days throughout their viable temperature range of 0 to 23 degrees C. Immunoperoxidase staining confirmed that viral replication occurred in the cytoplasm of acinar cells of salivary glands, both by ligh microscopy and electron microscopy. Replication of another subarctic Bunyavirus, Northway, and a subtropical Flavivirus, Murray Valley encephalitis, was also demonstrated by infectivity by infectivity titrations and immun operoxidase reactions in salivary glands of A. communis incubated at 0, 13, and 23 degrees C for 7 to 21 days.

Aedes↗
PubMed1975

Arbovirus growth in Aedes aegypti mosquitoes throughout their viable temperature range.

After intrathoracic inoculation of laboratory-bred Aedes aegypti mosquitoes with 3 Yukon isolates of California encephalitis (CE) virus (showshoe hare subtype), Northway (NOR) and Murray Valley encephalitis (MVE) viruses, viral replication was observed following incubation at 13, 21, 35 and 39 degrees C, which constituted the full temperature range of viability of A. aegypti. Rates of viral replication were reduced at low temperatures and accelerated at high temperatures. Virus-specific immunoperoxidase staining of mosquito salivary glands occurred regularly after thoraces attained maximum infectivity levels. At 13 and 21 degrees C, mosquitoes were infected by 10 to 100 times less CE and MVE viruses than mice, but about 10 times more NOR virus was required to infect mosquitoes than mice.

Aedes↗
PubMed1975

California encephalitis virus development in mosquitoes as revealed by transmission studies, immunoperoxidase staining, and electron microscopy.

Isolates of the snowshoe hare subtype of California encephalitis (CE) virus from Yukon mosquitoes during 1972 and 1973 were transmitted by bites of Aedes aegypti mosquitoes after 4 to 5 weeks of extrinsic incubation at 55 degrees F after intrathoracic injection, and the 1973 strain was transmitted after mosquitoes were fed virus and held for 3 to 4 weeks at 75 degrees F. Antigen of a 1971 isolate of CE virus (Marsh Lake 23) was detected in salivary glands of infected mosquitoes by the immunoperoxidase technique, using highly purified antiserum before and after conjugation with horseradish peroxidase, plus the use of orthotolidine as a substitute for benzidine. enveloped virions 45 nm in diameter were observed in thin sections of salivary glands of Culiseta inornata mosquitoes 59 days after intrathoracic injection with the 1971 isolate, afterincubation at 55 degrees F.

Aedes↗
PubMed1975

California encephalitis virus prevalence throughout the Yukon Territory, 1971-1974.

California encephalitis (CE) virus (snowshoe hare subtype) was isolated from 1 of 38 pools comprising 970 unengorged female Aedes canadensis mosquitoes and from 3 of 152 pools containing 5,676 A. communis mosquitoes which were collected in the Yukon Territory, Canada between latitudes 61 and 66 degrees N during June and July 1974. During four summers 1971 through 1974, this virus was recovered from 26 of 648 pools derived from 30,686 mosquitoes of 4 species. Isolation of CE virus from 1 of 109 pools of Aedes sp. larvae collected during May 1974 suggests maintenance of this virus over winter by transovarial transfer. Infectivity has been maintained in Culiseta inornata mosquitoes which were held continuously at 32 degrees F for 138 days. Neutralizing antibodies to CE virus were detected in 705 of 4,913 (14%) mammals collected during summers 1971 through 1974, including 430 of 1,076 (40%) snowshoe hares (Lepus americanus), 266 of 3,610 (7%) ground squirrels (Citellus undulatus) and 9 of 227 (4%) red squirrels (Tamiasciurus hudsonicus).

Aedes↗
PubMed1973

California encephalitis virus endemicity in the Yukon Territory, 1972.

Sera from 218 of 1574 (14%) small mammals collected in the Yukon Territory between 14 May and 13 August 1972 neutralized a Yukon strain of California encephalitis virus (snowshoe-hare subtype). These included 133 of 319 (42%) snowshoe hares (Lepus americanus), 84 of 1243 (7%) ground squirrels (Citellus undulatus) and 1 of 12 (8%) tree squirrels (Tamiasciurus hudsonicus). California encephalitis virus (snow-shoe hare subtype) was isolated from four pools of unengorged Aedes communis mosquitoes collected near Whitehorse (61 degrees N., 135 degrees W.) and on one occasion each from pools of the same species collected at Hunker Creek (64 degrees N., 138 degrees W.) and at mile 125, Dempster Highway (66 degrees N., 138 degrees W.) during July 1972. Replication of a Yukon strain of California encephalitis virus was observed in wild-caught Culiseta inornata and Aedes canadensis mosquitoes after intrathoracic injection and holding at temperatures of 80 degrees , 50 degrees and 40 degrees F.

Animals↗