scholarly journals LABORATORY TRANSMISSION OF ST. LOUIS ENCEPHALITIS VIRUS BY THREE GENERA OF MOSQUITOES

1943 ◽  
Vol 78 (4) ◽  
pp. 241-253 ◽  
Author(s):  
W. McD. Hammon ◽  
W. C. Reeves
Keyword(s):  
Incubation Period ◽  
Culex Quinquefasciatus ◽  
Culex Pipiens ◽  
Culex Tarsalis ◽  
Subcutaneous Route ◽  
Aedes Vexans ◽  
Epidemiologic Evidence ◽  
Anopheles Maculipennis ◽  
Aedes Taeniorhynchus ◽  
Culex Stigmatosoma

1. St. Louis virus has been successfully transmitted in the laboratory by the following 9 species of mosquitoes from 3 genera: Culex tarsalis, Culex pipiens, Culex coronator, Aedes lateralis, Aedes taeniorhynchus, Aedes vexans, Aedes nigromaculis, Theobaldia incidens, and Theobaldia inornata. 2. Though transmission has not been demonstrated, survival of the virus for more than a few days was shown to occur in Culex quinquefasciatus, Culex stigmatosoma, Psorophora ciliata, and Anopheles maculipennis freeborni. 3. In experiments with Culex tarsalis, infection occurred from feeding on chickens and ducks which had been previously inoculated by the subcutaneous route. After an incubation period these mosquitoes infected other chickens and virus was in turn demonstrated in the blood of these. This is interpreted as proof that fowl may serve as reservoirs of virus in nature. Since mosquitoes have been repeatedly found naturally infected with St. Louis virus and epidemiologic evidence supports their incrimination, their rôle as vectors is now established. The fully incriminated species is Culex tarsalis.

scholarly journals LABORATORY TRANSMISSION OF WESTERN EQUINE ENCEPHALOMYELITIS VIRUS BY MOSQUITOES OF THE GENERA CULEX AND CULISETA

1943 ◽  
Vol 78 (6) ◽  
pp. 425-434 ◽  
Author(s):  
W. McD. Hammon ◽  
W. C. Reeves
Keyword(s):  
Guinea Pig ◽  
Culex Tarsalis ◽  
Epidemiologic Evidence ◽  
Anopheles Maculipennis ◽  
Encephalomyelitis Virus ◽  
Culiseta Inornata ◽  
Western Equine Encephalomyelitis Virus ◽  
Culex Stigmatosoma ◽  
The Brain ◽  
Culiseta Incidens

1. Western equine virus has been successfully transmitted in the laboratory by 3 species of mosquitoes from 2 genera not previously reported as laboratory vectors: Culex tarsalis, Culiseta inornata, and Culiseta incidens. 2. Though transmission was not demonstrated, survival of the virus for more than a few days was shown to occur in Culex stigmatosoma and Psorophora confinnis. Possibly transmission occurred by the former. 3. In experiments with Culex tarsalis, infection of the mosquitoes occurred from feeding on an inoculated guinea pig, a duck, and virus-blood suspensions. After an incubation period of 10 to 30 days at a temperature above 25°C. these mosquitoes infected chickens and a guinea pig by their bite and virus was in turn demonstrated in the blood of the chickens and in the brain of the guinea pig. A total of 12 transmissions occurred. The fact that mosquitoes can be infected from fowl and in turn transmit to fowl, together with much other supporting data from field and laboratory, is interpreted as strengthening evidence that fowl serve as reservoirs of virus in nature. 4. Since Culex tarsalis mosquitoes have been repeatedly found infected with Western equine virus and epidemiologic evidence supports their incrimination, the vector rôle of this species is now established, and it may be regarded as fully incriminated. 5. Culiseta inornata has also been found infected in nature and now proven a laboratory vector. This species does not fit the epidemiological picture in the Yakima Valley as well as C. tarsalis, but may play an important rôle elsewhere. 6. Anopheles maculipennis freeborni and Culex pipiens found naturally infected have not transmitted the virus under laboratory conditions.

Evaluation of species composition and seasonal dynamics of mosquito larvae in the Košice Basin during 2010 and 2011

Biologia ◽  
2013 ◽  
Vol 68 (2) ◽  
Author(s):  
Eva Bocková ◽  
Alica Kočišová ◽  
Helena Hlavatá
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Seasonal Dynamics ◽  
Culex Pipiens ◽  
Mosquito Species ◽  
Mosquito Larvae ◽  
Aedes Vexans ◽  
Anopheles Maculipennis

AbstractIn six sites in the Košice Basin we collected 17,520 larvae of 15 mosquito species during the seasons (April–August) of 2010 and 2011. They were: Aedes vexans (Meigen, 1830), Ae. cinereus (Meigen, 1818) [or Ae. rossicus (Dolbeskin, Gorickaja & Mitrofanova, 1930], Ochlerotatus geniculatus (Olivier, 1791), Oc. refiki (Medschid, 1928), Oc. rusticus (Rossi, 1790), Oc. sticticus (Meigen, 1838), Oc. punctor (Kirby, 1837), Oc. cataphylla (Dyar, 1916), Oc. cantans (Meigen, 1818)[or Oc. annulipes (Meigen, 1830)], Oc. communis (De Geer, 1776), Oc. flavescens (Müller, 1764), Oc. leucomelas (Meigen, 1804), Culiseta annulata (Schrank, 1776), Culex pipiens (L., 1758) [or Cx. torrentium (Martini, 1925)] and Anopheles maculipennis s.l. The objective of the present research was to identify the mosquito larvae species diversity and compare their distribution and density in urban and suburban localities of the monitored territory.

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.

scholarly journals Gonoactivity of Culex (Culex) (Diptera: Culicidae) Mosquitoes During Winter in Temperate Argentina

2021 ◽  
Author(s):  
María Florencia Branda ◽  
Magdalena Laurito ◽  
Andrés Mario Visintin ◽  
Walter Ricardo Almirón
Keyword(s):  
Developmental Stage ◽  
Culex Quinquefasciatus ◽  
Culex Pipiens ◽  
Life Cycles ◽  
Morphological Identification ◽  
Dry Ice ◽  
Culex Pipiens Pipiens ◽  
Host Seeking ◽  
Baited Traps ◽  
The City

Abstract The subgenus Culex L. includes species involved in summer–autumn arbovirus transmission but studies during winter are scarce in temperate Argentina. Female specimens were collected host-seeking at dry-ice-baited traps during autumn–winter–spring at two sites in Córdoba City during 2016 and 2017. The specimens were morphologically identified and dissected to determine the follicular developmental stage (gonotrophic activity). Females with advanced follicular stages (≥III) were subjected to molecular procedures to confirm or re-identify previous morphological identification. Five species (Culex apicinus Philippi (Diptera: Culicidae), Culex dolosus (Lynch-Arribálzaga) (Diptera: Culicidae), Culex maxi Dyar (Diptera: Culicidae), Culex pipiens pipiens L. (Diptera: Culicidae), and Culex quinquefasciatus Say (Diptera: Culicidae)) were collected and found gonoactive during winter; showing that a high proportion of Culex (Culex) females remain reproductively active during the unfavorable season for mosquito populations. Among them, it is worth noting the collection of Cx. quinquefasciatus, vector of the St. Louis encephalitis virus (endemic in the city), a specimen of Cx. p. pipiens, and a hybrid of Cx. p. pipiens/Cx. quinquefasciatus (during autumn). The study of this community during winter should continue because a high gonoactive female proportion with advanced follicular stages was found: 29.12 and 13.07% in 2016 and 2017, respectively. Local studies such as this one provide evidence about ornithophilic Culex species with active year-round life cycles, species that could favor arbovirus overwintering.

The Susceptibility of various Species of Mosquitos to DDT, Dieldrin and BHC

1955 ◽  
Vol 46 (2) ◽  
pp. 301-309 ◽  
Author(s):  
R. H. Wharton
Keyword(s):  
Aedes Aegypti ◽  
Culex Pipiens ◽  
Lethal Concentration ◽  
Median Lethal Concentration ◽  
Adult Females ◽  
Anopheles Maculipennis ◽  
Culex Pipiens Molestus ◽  
Filter Papers

The susceptibility of various mosquitos to DDT, dieldrin and BHC has been studied. Adult females were exposed in small tubes lined with filter papers impregnated with insecticide-oil solutions. Larvae were exposed to insecticideacetone suspensions in water.Adult mosquitos tested in London showed no striking differences in susceptibility to DDT, though the median lethal concentration (MLC) of Culex pipiens molestus Forsk. (1·6 per cent.) was greater than the MLC of Aëdes aegypti (L.) (0·9), Anopheles maculipennis var. atroparvusvan Thiel (1·0), or A. quadrimaculatus Say (·7). C. p. molestus and Aë. aegypti showed the same order of susceptibility to dieldrin and BHC, with Anopheles m. atroparvus more susceptible to both insecticides.

Vector survival and parasite infection: the effect of Wuchereria bancrofti on its vector Culex quinquefasciatus

Parasitology ◽  
2004 ◽  
Vol 129 (1) ◽  
pp. 43-50 ◽  
Author(s):  
K. KRISHNAMOORTHY ◽  
S. SUBRAMANIAN ◽  
G. J. VAN OORTMARSSEN ◽  
J. D. F. HABBEMA ◽  
P. K. DAS
Keyword(s):  
Incubation Period ◽  
Culex Quinquefasciatus ◽  
Geometric Mean ◽  
Wuchereria Bancrofti ◽  
Parasite Load ◽  
Infected Mosquito ◽  
Parasite Development ◽  
Mosquito Vector ◽  
Extrinsic Incubation Period ◽  
Parasite Loss

This paper investigates a cohort of 2187 laboratory reared Culex quinquefasciatus fed on 69 human volunteers, including 59 persons with different levels of Wuchereria bancrofti microfilariae and 10 without microfilaria. Mosquitoes were followed until death. Mosquito survival was analysed in relation to the level of microfilaria in the human and larval count in the dead mosquito. Vector mortality during the extrinsic incubation period (12 days post-engorgement) was significantly higher in mosquitoes fed on microfilaraemic volunteers (50%) than in those fed on amicrofilaraemics (29%). Both the percentage infected and the geometric mean parasite density was significantly higher among mosquitoes which died before 13 days (45% infected and 10 larvae per infected mosquito) than those surviving beyond 13 days (39% and 2·2), suggesting a parasite loss of more than 80% during the extrinsic incubation period. A large proportion (62%) of the mosquitoes that died during the early of phase of parasite development were infected (36% in low, 26% in medium and 90% in high human Mf-density). Survival analysis showed that the parasite load in mosquitoes and the human Mf-density for a given parasite load are independent risk factors of vector survival. Overall, the hazard of dying was found to be 11–15 times higher among mosquitoes fed on microfilaraemic volunteers than those fed on amicrofilaraemics. The hazard doubles for every increase of about 60–70 parasites in the vector. As a consequence of the parasite-induced reduction in vector survival, the transmission success of the parasite is reduced. The implication of the results on control/elimination of lymphatic filariasis using mass-drug administration is discussed.

scholarly journals North American Culex pipiens and Culex quinquefasciatus are competent vectors for Usutu virus

2018 ◽  
Vol 12 (8) ◽  
pp. e0006732 ◽  
Author(s):  
Christian L. Cook ◽  
Yan-Jang S. Huang ◽  
Amy C. Lyons ◽  
Barry W. Alto ◽  
Isik Unlu ◽  
...  
Keyword(s):  
Culex Quinquefasciatus ◽  
North American ◽  
Culex Pipiens ◽  
Usutu Virus
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