West nile virus illinois

The best way to prevent West Nile encephalitis and other mosquito-borne illnesses is to reduce the number of mosquitoes around your home and neighborhood and to take personal precautions to avoid mosquito bites. In Illinois, West Nile virus was first identified in September when laboratory tests confirmed its presence in two dead crows found in the Chicago metropolitan area.

In , birds, mosquitoes and horses in of the state's counties were reported positive for West Nile virus and the first human cases and deaths from West Nile virus illness in Illinois were reported in August By the end of the year, the state lead the nation with more than human cases and 62 deaths. The Illinois Department of Public Health IDPH maintains a sophisticated disease surveillance system to monitor animals and insects that can potentially carry the virus: dead crows and blue jays, mosquitoes and horses.

Mosquitoes can either carry the virus or get it by feeding on infected birds. The surveillance system also includes infectious disease physicians, hospital laboratory directors and infection control practitioners, local health departments and staff from IDPH's laboratory, environmental health and infectious diseases divisions who test for and report suspect or confirmed cases of various diseases that can be caused by mosquito-borne viruses.

Source: Illinois Department of Public Health. Incidences in Illinois In Illinois, West Nile virus was first identified in September when laboratory tests confirmed its presence in two dead crows found in the Chicago metropolitan area. Birds contaminated feeders with low levels of WNV. In Cook Co. Recent tests of samples suggest an increase in the discontinuity between VecTests and TaqMan, possibly reflecting local variation in WNV antigenic properties and nucleic acid sequences.

Bloodmeal analysis and seroprevalence studies implicated the same avian species as major hosts; American robins, northern cardinals, mourning doves, and house sparrows. The rank in seroprevalence, however, did not necessarily agree with the rank in blood meals. American robins, for example, outnumbered the other species in the blood meal analysis, but not in seroprevalence. The proportion of mammal vs. One crow blood and one human blood were found in 50 blood meals identified to species, indicating these species were low preference.

In Central Illinois, both molecular analysis and morphology of male reproductive structures showed that hybrids of Cx. This area is usually considered outside the northern boundary of the hybrid zone. The start of mosquito breeding was early, March and April in Central Illinois, and early season Cx.

This suggests overwintering Cx. WNV was not detected in overwintering Cx. Impacts These data challenge several previous conclusions: 1 No late season increase in mammal feeding was found as reported for the East Coast. A similar late season oviposition pattern was noted for Cook Co, but is unlikely due to Cx.

These studies established basics of the urban transmission cycle in central and northern IL, and testable hypotheses can now be developed to elucidate critical determinants of transmission and when intervention might be most efficaceous. Publications Lampman, R. Culex population dynamics and West Nile virus transmission in east-central Illinois. Journal American Mosquito Control Assoc. Edillo, F. S, Nov. Gu, W. Statistical estimation of degree days of mosquito development under fluctuating temperatures in the field.

Journal of Vector Ecology. Ward, M. Does the roosting behavior of birds affect transmission dynamics of West Nile virus? American Journal of Tropical Medicine and Hygiene. Bunde, J. A survey for West Nile virus in bats from Illinois. Journal of Wildlife Diseases. Sanogo, Y. Disruption of the Wolbachia surface protein gene wspB by a transposable element in mosquitoes of the Culex pipiens complex Diptera, Culicidae. Insect Molecular Biology. The main West Nile virus WNV vectors were Culex pipiens and Culex restuans, outnumbering detections of all other species by 30 to fold.

Culex salinarius and Cx. Numbers of Culex pipiens peaked in August and Cx. Degree-day and maximum temperature models threshold 27C predicted Cx. Analysis of Culex specimens was consistent with the avian seropositive rates, verifying the role of Culex and passerine birds as primary vectors and hosts.

Captures of seronegative bird species suggested either low exposure rate or high mortality rate. The temporal patterns of infection rates in mosquitoes and seropositive rates in birds did not parallel each other, except with juvenile birds, reflecting the confounding nature of seasonal bird dispersal patterns and year-to-year survivorship of antibody positive birds.

We are sequencing West Nile Virus strains collected from different location in Illinois. We have also developed a real-time PCR technique to detect and quantify West Nile Virus vectors, which will help determine the role of each mosquito species in WNV transmission and help target our approach to surveillance and control. Impacts These studies help determine which species of mosquitoes are likely vectors of WNV, which helps to target specific control measures.

The information on bird infections will aid in assessing morbidity and mortality of Illinois wildlife to WNV, and also to predict which species can serve as bridge vectors of the virus.

We showed that the distribution of one vector -- Culex quinquefasciatus -- is expanding north. Moreover, we detected intermediate forms hybrids of the two species during the winter.

This can have very important health implications because Culex quinquefasciatus -- which bites preferentially mammals including man -- cannot overwinter, whereas Culex pipiens - which feeds mainly on birds -- can overwinter. Their hybrid forms could serve as a bridge vector for the transmission of West Nile virus to humans. The study is yielding results that will be of value in mosquito management programs, ensuring that infections of humans can be minimized through science-based management recommendations.

Publications Davis, C. Phylogenetic analysis of North American West Nile Virus isolates Evidence for the emergence of a dominant genotype. Virology Reno, H. Characterization of a pyrase-like activity in Aedes triseriatus, Aedes hendersoni and Aedes aegypti. American Journal of Tropical Medicine and Hygiene Jacob, B. Comparing GPS technology for identifying spatial ecological variation for urban mosquito management. Wing Beats Rapaport, A.