Virus isolations from mosquitoes in southern Ontario, 1976 and 1977

1980 ◽  
Vol 26 (4) ◽  
pp. 436-440 ◽  
Author(s):  
J. Thorsen ◽  
H. Artsob ◽  
L. Spence ◽  
G. Surgeoner ◽  
B. Helson ◽  
...  
Keyword(s):  
Culex Pipiens ◽  
The Other ◽  
Snowshoe Hare ◽  
Light Traps ◽  
Southern Ontario ◽  
Cache Valley Virus ◽  
Cache Valley ◽  
Virus Activity ◽  
Bursal Disease ◽  
California Serogroup

Following the 1975 epidemic of St. Louis encephalitis (SLE) in Ontario, programs were instituted to monitor virus activity in mosquito populations during 1976 and 1977. Mosquitoes were trapped with CDC light traps and CO2 cone traps, pooled by species, and tested for virus by intracerebral inoculation of suckling mice. In 1976, 51 175 mosquitoes were tested. SLE virus was isolated from two mixed pools of Culex pipiens – C. restuans mosquitoes. Five isolations of California serogroup viruses were made. Three of these were trivittatus virus, which has not been demonstrated previously in Canada, and the other two were snowshoe hare virus. Other viruses isolated in 1976 were a virus antigenically identical to the virus of infectious bursal disease of chickens and 34 Flanders viruses. In 1977, 34 428 mosquitoes were tested. Flanders virus was isolated most frequently, from pools of mixed C. pipiens – C. restuans mosquitoes. The only other isolate was a Bunyamwera group virus, Cache Valley virus. This virus has not been reported previously in Ontario.

Culex pipiens (Culicidae) is attracted to humans in southern Ontario, but will it serve as a bridge vector of West Nile virus?

2012 ◽  
Vol 144 (5) ◽  
pp. 667-671 ◽  
Author(s):  
Curtis Russell ◽  
Fiona F. Hunter
Keyword(s):  
West Nile Virus ◽  
Disease Control ◽  
Culex Pipiens ◽  
Forest Canopy ◽  
Ground Level ◽  
Light Traps ◽  
Aedes Vexans ◽  
West Nile ◽  
Southern Ontario ◽  
Baited Traps

AbstractWe tested whether the known bird-biting mosquito, Culex pipiens Linnaeus (Diptera: Culicidae), is attracted to human hosts by placing humans at ground level (∼1.5 m) or in the forest canopy (∼5 m) in a Niagara woodlot. Modified Centers for Disease Control (CDC) miniature light traps (no light, no CO2) were placed next to the human hosts to capture the attracted mosquitoes. The human-baited traps were compared with control traps (standard CDC miniature light traps with CO2, but no light). As expected from previous research, there were more C. pipiens captured at the higher elevation than at ground level. Generally, they were attracted to control traps more than to human-baited traps at 5 m, whereas at 1.5 m there was no difference between the two trap types. As a comparison, most Aedes vexans (Meigen) mosquitoes were captured at the 1.5 m elevation but there were significantly more captured in the control traps than the human-baited traps during all periods. Because C. pipiens is attracted to humans throughout the entire season at the 1.5 m height (where they might encounter humans), it is likely that C. pipiens can serve as a bridge vector of West Nile virus (WNV).

Influence of elevation and avian or mammalian hosts on attraction of Culex pipiens (Diptera: Culicidae) in southern Ontario

2010 ◽  
Vol 142 (3) ◽  
pp. 250-255 ◽  
Author(s):  
Curtis Russell ◽  
Fiona F. Hunter
Keyword(s):  
West Nile Virus ◽  
Culex Pipiens ◽  
Potential Role ◽  
Late Period ◽  
Light Traps ◽  
Southern Ontario ◽  
Baited Traps ◽  
Significant Difference ◽  
Important Exception

AbstractWe studied Culex pipiens L. in the Niagara Region of Ontario, Canada, to establish whether or not these mosquitoes are attracted to hosts other than birds at different elevations or as the season progresses. Guinea-pigs and chickens were used as representative mammalian and avian hosts, respectively. Bait animals were placed next to modified CDC miniature light traps (no light and no CO2) hung 1.5 or 5 m above ground in a Niagara woodlot. The season was divided into three 6-week periods (early, middle, and late). Significantly more C. pipiens were captured at the 5 m than at the 1.5 m elevation. In general, chicken-baited traps were preferred over control and guinea-pig-baited traps, with one important exception: there was no significant difference among traps during the late period at 1.5 m elevation. The potential role of C. pipiens as a bridging vector of West Nile virus to humans is discussed.

Mosquitoes (Diptera: Culicidae) of the Lower Dyje River Basin (Podyjí) at the Czech-Austrian border

2012 ◽  
Vol 7 (2) ◽  
pp. 288-298 ◽  
Author(s):  
Oldřich Šebesta ◽  
Ivan Gelbič ◽  
Jan Minář
Keyword(s):  
Czech Republic ◽  
River Basin ◽  
Culex Pipiens ◽  
Mosquito Species ◽  
The Other ◽  
Light Traps ◽  
Aedes Vexans ◽  
Dry Ice ◽  
Anopheles Maculipennis ◽  
Austrian Border

AbstractDuring 2009–2011, mosquitoes were captured in CDC miniature light traps using CO2 (dry ice) at six sites in the Lower Dyje River Basin (Czech Republic). Other methods of capture — sweeping from vegetation and collection of larvae and pupae from ponds — were also used for more precise diagnostics. Thirty mosquito species of six genera were confirmed. A total of 415,218 females were captured. Most frequently found were the outbreak species Aedes vexans (56.52% of all mosquitoes collected) and Ae. sticticus (16.40%). Among other flood species, Ae. rossicus (5.17%), Ae. cantans and Ae. annulipes (2.44% of all females collected), and Ae. cinereus s. l. (1.11%) were especially abundant. Females of Ae. cataphylla were captured in spring (0.31%) and Ae. intrudens was numerous only at one site. Among the other species, Culex pipiens s. l. (6.61%) and Cx. modestus (8.87%) were abundant. Anopheles maculipennis s. l. (1.01%), An. claviger (0.43%), An. plumbeus (0.08%), An. hyrcanus (0.08%), Coquillettidia richiardii (0.52%) and Culiseta annulata (0.18%) were also detected. Sparsely occurring were Ae. excrucians, Ae. flavescens, Ae. caspius and Ae. geniculatus. Captured only very sporadically were Ae. communis, Ae. leucomelas, Ae. dorsalis, Ae. rusticus, Cx. martinii, Cx. territans, Cs. morsitans and Uranotaenia unguiculata.

California encephalitis virus activity in mosquitoes and horses in southern Ontario, 1975

1978 ◽  
Vol 24 (12) ◽  
pp. 1544-1547 ◽  
Author(s):  
H. Artsob ◽  
R. Wright ◽  
L. Shipp ◽  
L. Spence ◽  
C. Th'ng
Keyword(s):  
Encephalitis Virus ◽  
Snowshoe Hare ◽  
Serological Testing ◽  
Southern Ontario ◽  
Suckling Mice ◽  
Virus Activity

A study was undertaken in 1975 to determine California encephalitis virus activity in southern Ontario. Three thousand and sixty-one mosquitoes, primarily Aedes species, were divided into 104 pools and inoculated into suckling mice. Isolates of snowshoe hare virus were obtained from one pool each of Aedes fitchii and A. triseriatus mosquitoes collected in the Guelph area. Serological testing of horse sera revealed extensive virus activity in southern Ontario and indicated that horses may serve as excellent monitors for California encephalitis virus.

scholarly journals Second Human Case of Cache Valley Virus Disease

2006 ◽  
Vol 12 (5) ◽  
pp. 854-856 ◽  
Author(s):  
Grant L. Campbell ◽  
James D. Mataczynski ◽  
Erik S. Reisdorf ◽  
James W. Powell ◽  
Denise A. Martin ◽  
...  
Keyword(s):  
Virus Disease ◽  
Human Case ◽  
Cache Valley Virus ◽  
Cache Valley

scholarly journals Intercalibration of different light-traps and bulbs used in moth monitoring in northern Europe

1998 ◽  
Vol 9 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Reima Leinonen ◽  
Guy Söderman ◽  
Juhani Itämies ◽  
Seppo Rytkönen ◽  
Ilpo Rutanen
Keyword(s):  
The Other ◽  
Northern Europe ◽  
Mercury Vapour ◽  
Light Traps ◽  
Mercury Vapour Lamp ◽  
Species Being ◽  
Tungsten Lamp

Four different combinations of light-traps and bulbs were tested during the summer 1996 in Kainuu, northern Finland: a Jalas model with a 160-W (J/160W) blended light lamp or a 125-W (J/125W) mercury vapour lamp, a Ryrholm trap with a 125-W (R/125W) mercury vapour lamp and a Rothamsted trap with a 200-W tungsten lamp (G/200W). The traps were rotated between four sites every night, but were kept in the same position for the fifth night in order to prevent the possible influence of moonlight. The longest distance between the traps was 150m, and there was no direct visibility between any of them. Three orders were inspected, i.e. Lepidoptera, Coleoptera and Hemiptera, the total numbers of individuals and species being as follows: 20857/425, 862/101 and 1868/58. G/200W collected significantly fewer moths than the other traps. In some cases, J/125W collected significantly more moths and less species than the J/160W design. The R/125W design collected significantly more species than the J/160W design. Similar differences in the effectiveness of the lamps and traps were found in the case of Coleoptera and Hemiptera. Alpha diversities showed the same trend.

Cache Valley virus: experimental infection in Culiseta inornata

1980 ◽  
Vol 26 (3) ◽  
pp. 287-290 ◽  
Author(s):  
Linda C. Corner ◽  
Audrei K. Robertson ◽  
Lance B. Hayles ◽  
John O. Iversen
Keyword(s):  
Blood Meal ◽  
Lethal Dose ◽  
Experimental Demonstration ◽  
Female Progeny ◽  
Cache Valley Virus ◽  
Suckling Mice ◽  
Cache Valley ◽  
Culiseta Inornata ◽  
Minimum Infection Rate

Experiments were conducted to examine the dynamics of Cache Valley virus in Culiseta inornata, the probable chief vector of the virus. Of about 1500 laboratory reared C. inornata exposed to viraemic suckling mice, 72 took a blood meal. A relatively high percentage (93%) of the latter mosquitoes became infected. The virus increased more than 100-fold in the experimentally infected mosquitoes. The increasing viral titres were noticed after 7 days and after 15 days. Peak titres averaged 105.0 (mean suckling mouse intracerebral lethal dose) SMICLD50/0.02 mL. The infected mosquitoes had peak titres until at least 35 days after the mosquitoes ingested blood from infected suckling mice. A single transmission of virus by bite occurred 30 days after the viraemic blood meal. Transovarial transmission was demonstrated. In two experiments, 3.3 and 2.9% of infected mosquitoes transovarially transmitted Cache Valley virus to both male and female progeny. The minimum infection rate for the progeny was 2.05/1000 mosquitoes. This is the first reported experimental demonstration of transovarian transmission in a species of mosquito which overwinters as an adult. The role of transovarian transmission in the natural maintenance of Cache Valley virus remains undetermined.

scholarly journals Roles of Host Species, Geographic Separation, and Isolation in the Seroprevalence of Jamestown Canyon and Snowshoe Hare Viruses in Newfoundland

2012 ◽  
Vol 78 (18) ◽  
pp. 6734-6740 ◽  
Author(s):  
Gregory Goff ◽  
Hugh Whitney ◽  
Michael A. Drebot
Keyword(s):  
Host Species ◽  
Neutralization Assay ◽  
Snowshoe Hare ◽  
Large Mammals ◽  
Content Type ◽  
Neuroinvasive Disease ◽  
Snowshoe Hares ◽  
Jamestown Canyon Virus ◽  
Geographic Separation ◽  
California Serogroup

ABSTRACTCalifornia serogroup viruses, including Jamestown Canyon virus (JCV) and snowshoe hare virus (SSHV), are mosquito-borne members of theBunyaviridaefamily and are endemic across North America. These arboviruses are potential pathogens which occasionally cause neuroinvasive disease in humans and livestock. A neutralization assay was used to document JCV and SSHV seroprevalence using blood collected from a variety of domestic and wildlife host species. These species were sampled in an island setting, Newfoundland, which contains diverse ecoregions, ecological landscapes, and habitats. Seroprevalence rates for each virus differed significantly among host species and within certain species across different geographic areas. JCV was significantly associated with large mammals, and SSHV was significantly associated with snowshoe hares. Seroprevalence rates in the 5 species of animals tested for prior exposure to JCV ranged from 0% in snowshoe hares to 64% in horses. Seroprevalence rates for SSHV ranged from less than 1% in bovines to 55% in all snowshoe hares. The seroprevalence of SSHV differed significantly (P< 0.05) among hares occupying the discrete habitats of watersheds separated by 14 to 35 km. Cattle on farms in boreal forest landscapes displayed significantly higher JCV seroprevalence (P< 0.001) than those on farms located in seacoast landscapes. Lifelong geographic isolation of cattle to insular Newfoundland was associated with significantly lower JCV seroprevalence (P< 0.01) than that for cattle which had lived off-island.

Cache Valley virus: isolations from mosquitoes in Saskatchewan, 1972–1974

1979 ◽  
Vol 25 (6) ◽  
pp. 760-764 ◽  
Author(s):  
J. O. Iversen ◽  
R. J. Wagner ◽  
M. K. Leung ◽  
L. B. Hayles ◽  
J. R. McLintock
Keyword(s):  
Infection Rate ◽  
Culex Tarsalis ◽  
Cache Valley Virus ◽  
Cache Valley ◽  
Culiseta Inornata ◽  
Minimum Vector

Eighteen isolations of Cache Valley virus (Bunyaviridae) were obtained from a total of 113 694 mosquitoes collected in Saskatchewan during the summers of 1972 to 1974. Most of the isolations were from mosquitoes collected during August. Culiseta inornata, the most abundant mosquito (38% of total collected), had the highest minimum vector-infection rate (0.83 isolations per 1000 mosquitoes). The virus was also isolated from Culex tarsalis and Aedes texans. It is indicated in the isolations that the prairie grasslands of the province are enzootic for Cache Valley virus.

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