FACTORS LED TO EVOLUTION OF ENDEMIC FOCI FOR WEST NILE VIRUS IN NEW YORK STATE

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0216425
• Project Start Date: Oct 1, 2008
• Project End Date: Sep 30, 2012
• Program Code: [(N/A)]- (N/A)

Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853

Performing Department
VET POPULATION MEDICINE & DIAGNOSTIC SCIENCE

Non Technical Summary
Our long term goal is to shed light on the mechanisms involved in the transfer and perpetuation of West Nile Virus (WNV) epidemic/epizootic disease to an endemic/enzootic disease form. This would be a great value in understanding the epidemiology of the disease and the factors that play role in transition between endemic and epidemic stages in agricultural foci and the risk to livestock. The recent WNV epidemic/epizootic in New York State is distinguished by unprecedented avian mortality, equine disease and the involvement of many vertebrate and vector species. Perennial outbreaks in the state suggest the local establishment of natural foci with perpetuation of the disease among susceptible hosts rather than reintroduction via migratory birds. However, we know very little with regard to maintenance of this endemicity of WNV dynamics in agricultural foci. Agricultural foci are sites of interaction between humans, domestic livestock, wildlife, and arthropod vectors; as such have the potential to function as the nidus for many emerging infectious diseases. Through the proposed epidemiologic studies we hope to shed light the mechanism by which the WNV is able to escape the host's detection and reconnaissance systems and establishes new niches. We are planning on conducting a series of complimentary epidemiologic, entomological, and environmental studies that identify potential risk factors associated with the presence of WNV within agricultural foci. This multi disciplinary approach will be carried out in farms within the NYC Watershed, where we have a well-established research program collaborating with local stakeholders collecting data on dairy cattle and wildlife. We will investigate putative factors related to the spectrum of hosts, vectors, and environment on agricultural foci in New York State. On-site farms including livestock, geographic features and management practices will be investigated for each location within the study site. At each selected farm, we will investigate the association of the exposure among livestock hosts, with the density and abundance estimates for mammalian and avian wildlife species, mosquitoes and other potential arthropod vectors. The information regarding both the abiotic and biotic factors such as habitat type, building placement and water features will be recorded and compared at each location. Assessing results between different sites will lead to the identification of potential risk factors that may enhance or diffuse the presence of WNV within agricultural foci. The public benefit indirectly from enhanced surveillance efforts designed to identify putative factors that potentially contribute to the perpetuation of WNV in NYS. County and extension staff will have improved understanding of pathogen exchange wildlife/livestock interface in agricultural ecosystems and the methods for maintaining the harmony between agriculture and the environment. The understanding could be used to develop science-based regulations. Researchers will gain considerable knowledge in the ecology and epidemiology of emerging epizootics.

Animal Health Component

50%

Research Effort Categories

Basic

30%

Applied

50%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
311	0820	1070	20%
311	0830	1170	20%
311	3410	1101	25%
311	3810	1170	25%
311	3810	1130	10%

Knowledge Area
311 - Animal Diseases;

Subject Of Investigation
0820 - Wild birds; 0830 - Wild animals; 3410 - Dairy cattle, live animal; 3810 - Horses, ponies, and mules;

Field Of Science
1101 - Virology; 1130 - Entomology and acarology; 1070 - Ecology; 1170 - Epidemiology;

Keywords

west nile virus endemic enzootic risk factors livestock agricultural

niches

Goals / Objectives
Our long term goal is to determine the mechanisms involved in the transfer of WNV epidemic/epizootic disease to an endemic/enzootic disease form. This would be of great value in understanding the ecology of mosquito-borne diseases and provide important information about the unpredictability of the inverse process. The specific aims of the proposed studies to be addressed through this funding are: 1) Determine the spectrum of potential reservoir among domestic agricultural animals on farms in the New York City Watershed (NYCW) ecosystem. 2) Determine the range of potential reservoirs among sylvatic animals on farms in the NYCW ecosystem. 3) Determine the types of mosquitoes involved in the perpetuation of the WNV infection in these ecological niduses within farms in the NYCW. 4) Determine the abundance of birds that are reported in the literature to be a reservoir for WNV in these niduses. Outputs: 1)Advances in our understanding of the epidemiology and ecology of WNV in agricultural environments. 2) Development of surveillance strategies for WNV and other potential epizootic diseases that enhance communications between wildlife scientists, public health officials, veterinary researchers, and stakeholders. 3) Provides the necessary information regarding the factors associated with the risk of maintenance reservoirs in agricultural settings so that intervention strategies can be devised. 4) Make recommendations regarding approaches to mitigate the risk WNV in NYS and hopefully extrapolating the results to other areas in the country to control and eradicate this disease.

Project Methods
We are planning a series of complimentary entomological, ecological, and epidemiologic studies that identify potential risk factors associated with the presence of WNV within NYS agricultural ecosystems. This multidisciplinary approach will be carried out in farms within the NYC Watershed. Using established ecological niche where farm management practices have been previously assessed we intend to examine abundance and diversity of local wildlife mosquitoes and other potential arthropod vector species. At each selected farm density and abundance estimates for wildlife species will be acquired primarily through trapping small mammals, bird census studies and insect trapping at individual farm locations. Simultaneously, efforts testing for WNV will be conducted on livestock, wildlife, and insects. The information regarding both the abiotic and biotic factors such as habitat type, building placement and water features will be recorded and compared at each location. Putative risk factors within each nidus, including abundance and diversity of local wildlife, mosquitoes and other potential arthropod vectors in each ecological niche, will be compared between cases and controls. Blood samples will be collected for a spectrum of vertebrate reservoir testing for antibodies to WNV using an ELISA test and/or presence of the virus using a PCR test. Active surveillance of equines will follow the serological status of a horse population which will be sampled regularly to detect specific sero-conversion areas where outbreaks have occurred sporadically and endemically. Milestones are: 1) identify the study niduses and the population at risk within these areas, prepare the sampling design for domestic animals and wildlife. First sampling begins (Mar 09); 2) second sampling will commence in the late summer where the mosquitoes are active. At the same time we will start the resting sampling for mosquitoes and identification of mosquitoes; 3) Oct-Mar-winter sampling and testing of domestic animals and wildlife and collection of data on putative risk factors; 4) Apr-Jul-10, second cycle (year) of sampling and testing of the domestic animals and wildlife. Any adjustment of the sampling plans will also be made as deemed necessary based on the first cycle of sampling. Also second cycle of domestic animals and wildlife sampling. At the same time we will start the resting sampling for mosquitoes and identification of mosquitoes. 5) Oct-10 to Mar-11: second cycle of winter sampling and testing of domestic animals and wildlife and collection of data on putative risk factors. Bird census will continue throughout the study. 6) Apr-Oct-11:Collation and analyses of data to develop the risk model and prepare the final report. Outcomes: 1) Advances in our understanding of the epidemiology of WNV in agricultural niches. 2) Development of surveillance strategies for WNV and other potential epizootic diseases that enhance communications among stakeholders. 3) Provides the necessary information on WNV disease so that intervention strategies can be devised. 4) Make recommendations regarding approaches to mitigate the risk WNV in NYS and beyond.

Progress 10/01/08 to 09/30/12

Outputs
OUTPUTS: The objective of our proposed studies was to use a tiered approach to collect data to assess the factors which might potentially place agricultural animals at a greater risk of infection of WNV. This investigation intends to explore the range of agricultural animals wildlife reservoirs of WNV frequently found in agricultural niches. In addition, we hope to identify the spectrum of mosquito vectors in this ecosystem. By examining findings within the context of each farm ecosystem we hope to identify ecological and management factors that could then be applied to future strategies to mitigate risk. During the reporting period we continued to collect blood samples from deer and raccoons and tested the samples for evidence of exposure to the West Nile Virus. The deer samples were collected in collaboration with the New York State Conservation Department. The Raccoons samples were collected in collaboration with the NYS Rabies program. The samples were tested using a commercial enzyme-linked immune sorbent assay (ELISA) donated by InterVet, Inc. We have been sharing our results with the collaborators at the Department of Health. The finding in these studies to date have partially contributed to our knowledge about the ecology of this virus in the targeted agricultural niches and showed that both raccoons and deer are likely to be reservoir to the virus in these agricultural niches. In addition we have shared our knowledge through presentation at international conference on emerging zoonotic diseases in Malaysia. We are continuing our collaborating with an international company that produces a commercial kit to investigate the risk of exposure to this virus in Malaysia and Kenya. Serum samples have been collected from wildlife and agricultural animals in these areas and examined for the presence of evidence of exposure to the virus. PARTICIPANTS: Hussni O. Mohammed, PI, Professor of Epidemiology, Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University, He designed the proposed studies, supervised the graduate student, Ms. Christine DeCarlo, whose this project is a part of her PhD training program. Amy L. Glaser, CoPI, Senior Research Associate, Assistant Director, Virology, Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University, She is supervising the molecular and serological activities that are being carried out in the proposed studies. Laura Bigler, Wildlife Expert and Research Associate at the Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University. She has been supervising the field studies on the wildlife and collecting the raccoon samples. Andre A. Dhondt, CoPI, Morgans Professor of Ornithology, Cornell Lab of Ornithology, Department of Ecology and Evolutionary Biology, College of Agriculture and Life Sciences, Cornell University Collaborators Laura C. Harrington, Associate Professor, Medical Entomology, Department of Entomology, College of Agriculture and Life Sciences, Cornell University, She has been advising our graduate student on the entomological studies on potential mosquito vectors in New York State as a part of a risk assessment study on WNV. She will continue to provide supervision on the proposed entomological studies. Training Opportunities: Ms. Christine Decarlo, She successfully completed all the requirements for her program PhD-graduate student at Cornell. Her PhD-thesis was based on the project. Sabrina Benteftifa, She is a an undergraduate at Cornell. She has been helping in the laboratory studies with emphasis on collection of blood samples from agricultural animals. Omar AH-He is an undergraduate student who ran the ELISA test on the deer and raccoon samples and collate the data. TARGET AUDIENCES: The proposed studies have provided the necessary information regarding the factors associated with the risk of maintenance reservoirs in agricultural settings so that intervention strategies can be devised. This information will be useful to farmers, extension personnel, and residence of the targeted agricultural niches to help development of educational materials related to the risk of the WNV and the strategies to mitigate the associated adverse consequences. We hope to work with the educational institutes and extension personnel in the agricultural niches to develop recommendations regarding approaches to mitigate the risk of WNV in NYS and hopefully extrapolating the results to other areas in the country to control and eradicate this disease. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Using the resources made available through this grant we continued to address our objectives of examining evidence of exposure to the virus among components of the agricultural ecosystem, namely, deer and raccoons. We continued to test serum samples collected from wildlife in the targeted agricultural niches for the presence of antibodies against the WNV. The results of the samples from wildlife, namely raccoon continued to support the premise that there is evidence of exposure to the virus among these species. Samples were collected from deer and tested for antibodies against the WNV. The observed seroconversion among deer is suggestive of the potential role for the animal as a reservoir for the WNV in the agricultural niches.

Publications

• DeCarlo CH, Glaser AL, Bigler LL, Mohammed HO. The role of dairy cattle and raccoons in the evolution of endemic foci for West Nile virus in New York State. Zoonoses and Public Health, 2012. (Submitted)
• DeCarlo CH, Campbell SR, Bigler LL, Mohammed HO. Potential vectors for West Nile Virus among invasive mosquito species in New York State. Ecology 2012 (submitted).
• Omar AH, DeCarlo CH, Bigler LL, Mohammed HO. Seroconversion rate to West Nile Virus among deer and raccoons in New York State. . Journal of Wildlife 2012 (Interpenetration).

Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: The objective of our proposed studies was to use a tiered approach to collect data to assess the factors which might potentially place agricultural animals at a greater risk of infection of WNV. This investigation intends to explore the range of agricultural animals wildlife reservoirs of WNV frequently found in agricultural niches. In addition, we hope to identify the spectrum of mosquito vectors in this ecosystem. By examining findings within the context of each farm ecosystem we hope to identify ecological and management factors that could then be applied to future strategies to mitigate risk. During the reporting period we continued to collect blood samples from cattle and raccoons and tested the samples for evidence of exposure to the West Nile Virus. We also continued to collect mosquitoes in the agricultural ecosystem and tested for the presence of the virus using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The RT-PCR assay that was developed during the previous period was used during this reporting period. We also used the assay for testing mosquitoes captured in these areas for infection with the WNV. We have been sharing our results with the collaborators at the Department of Health. The finding in these studies to date have partially contributed to our knowledge about the ecology of this virus in the targeted agricultural niches and showed cattle are unlikely to be reservoir to the virus in this agricultural niches. In addition we have shared our knowledge through presentation at international conference on emerging zoonotic diseases in Malaysia. We are currently collaborating with an international company that produces a commercial kit to investigate the risk of exposure to this virus in Malaysia and Kenya. Serum samples have been collected from wildlife and agricultural animals in these areas and examined for the presence of evidence of exposure to the virus. PARTICIPANTS: Participants Hussni O. Mohammed-Professor of Epidemiology, Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University-He designed the proposed studies, supervised the graduate student, Ms. Christine DeCarlo, whose this project is a part of her PhD training program. Amy L. Glaser-Senior Research Associate, Assistant Director-Virology, Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University-She is supervising the molecular and serological activities that are being carried out in the proposed studies. Laura Bigler-Wildlife Expert and Research Associate at the Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University. She has been supervising the field studies on the wildlife and collecting the raccoon samples. Collaborators: Laura C. Harrington, Associate Professor, Medical Entomology, Department of Entomology, College of Agriculture and Life Sciences, Cornell University-She has been advising our graduate student on the entomological studies on potential mosquito vectors in New York State as a part of a risk assessment study on WNV. She will continue to provide supervision on the proposed entomological studies. Training Opportunities: Ms. Christine Decarlo-She successfully completed all the requirements for her program PhD-graduate student at Cornell. Her PhD-thesis was based on the project. Sabrina Benteftifa-She is a an undergraduate at Cornell. She has been helping in the laboratory studies with emphasis on collection of blood samples from agricultural animals. Adil Omar-He is an undergraduate at Cornell. She has been helping in the laboratory studies with emphasis on collection of blood samples from agricultural animals. TARGET AUDIENCES: The proposed studies are expected to provide the necessary information regarding the factors associated with the risk of maintenance reservoirs in agricultural settings so that intervention strategies can be devised. This information will be useful to farmers, extension personnel, and residence of the targeted agricultural niches to help development of educational materials related to the risk of the WNV and the strategies to mitigate the associated adverse consequences. We hope to work with the educational institutes and extension personnel in the agricultural niches to develop recommendations regarding approaches to mitigate the risk of WNV in NYS and hopefully extrapolating the results to other areas in the country to control and eradicate this disease. PROJECT MODIFICATIONS: We have expanded the focus of the project to include wider geographic areas including Malaysia and Kenya. Our collaborators from Malaysia included: Prof. Dr. Abdul Rahman Omar-He is a professor of Virology at the Veterinary Faculty, University Putra Malaysia. He has been testing samples from the wildlife that are been collected in Malaysia and supervising the students in Malaysia. Dr. Jalia Abu-Assistant Professor of Wildlife, at the Veterinary Faculty, University Putra Malaysia. She has been collecting the samples of spectrum of wildlife in Malaysia.

Impacts
Using the resources made available through this grant we continued to use the developed TR-PCR test to detect the presence of the WNV among different species of mosquitoes capered in the targeted agricultural niches. We continued to demonstrate that there is no evidence of a virus circulation among the captured mosquitoes in the targeted areas in New York. So far all the mosquitoes that were tested with developed RT-PCR were negative for the presence of the virus. We continued to address our objectives of examining evidence of exposure to the virus among agricultural animals. We continued to test serum samples collected from cows and from wildlife in the targeted agricultural niches for the presence of antibodies against the WNV. All the samples from cows were negative. The results on these samples continued to date support the premise that, although cows are reported to be a potential reservoir for WNV in other part of the world they are not in the US. The results of the samples from wildlife, namely raccoon continued to support the premise that there is evidence of exposure to the virus among these species. We will continue to collect samples from the agricultural animals and test them for the presence of antibodies to the WNV. Samples were collected from wildlife (raccoon) and tested for antibodies against the WNV. The observed seroconversion among raccoons is suggestive of the potential role for the raccoon as a reservoir for the WNV in the agricultural niches. We will continue to collect samples from the wildlife and tested for the presence of antibodies. Samples from Malaysia shown that the prevalence of seroconversion is about 2%.

Publications

• DeCarlo CH, Ziegler PE, Glaser AL, Szonyi B, Mohammed HO. Factors led to evolution of endemic foci for West Nile Virus in New York State. International Symposia on Veterinary Epidemiology and Economics (ISVEE) proceedings, ISVEE 12: Proceedings of the 12th Symposium of the International Society for Veterinary Epidemiology and Economics, Durban, South Africa, August 2009.
• DeCarlo CH, Glaser AL, Szonyi B, Ahmed NI, and Mohammed HO. The risk of West Nile Virus among crows in New York State. Proceeding of the International Conference in ASZWM; Kuala Lumpur, Malaysia, August 2010.
• DeCarlo CH, Clark AB, McGowan KJ, Ziegler PE, Glaser AL, Szonyi B, Mohammed HO. Factors Associated With the Risk of West Nile Virus Among Crows in New York State. Zoonoses Public Health 2011; 58(4):270-5.

Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: The objective of our proposed studies was to use a tiered approach to collect data to assess the factors which might potentially place agricultural animals at a greater risk of infection of WNV. This investigation intends to explore the range of agricultural animals wildlife reservoirs of WNV frequently found in agricultural niches. In addition, we hope to identify the spectrum of mosquito vectors in this ecosystem. By examining findings within the context of each farm ecosystem we hope to identify ecological and management factors that could then be applied to future strategies to mitigate risk. During the reporting period we continued to collect blood samples from cattle and raccoons and tested the samples for evidence of exposure to the West Nile Virus. We also continued to collect mosquitoes in the agricultural ecosystem and tested for the presence of the virus using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The RT-PCR assay that was developed during the previous period was used during this reporting period. We also used the assay for testing mosquitoes captured in these areas for infection with the WNV. We have been sharing our results with the collaborators at the Department of Health. The finding in these studies to date have partially contributed to our knowledge about the ecology of this virus in the targeted agricultural niches and showed cattle are unlikely to be reservoir to the virus in this agricultural niches. In addition we have shared our knowledge through presentation at international conference on emerging zoonotic diseases in Malaysia. We are currently collaborating with an international company that produces a commercial kit to investigate the risk of exposure to this virus in Malaysia and Kenya. PARTICIPANTS: Participants: Hussni O. Mohammed, PI, Professor of Epidemiology, Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University. He designed the proposed studies, supervised the graduate student, Ms. Christine DeCarlo, whose this project is a part of her PhD training program. Amy L. Glaser, CoPI, Senior Research Associate, Assistant Director, Virology, Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University. She is supervising the molecular and serological activities that are being carried out in the proposed studies. Laura Bigler, Wildlife Expert and Research Associate at the Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University. She has been supervising the field studies on the wildlife and collecting the raccoon samples. Andre A. Dhondt, CoPI, Morgans Professor of Ornithology, Cornell Lab of Ornithology, Department of Ecology and Evolutionary Biology, College of Agriculture and Life Sciences, Cornell University Collaborators: Laura C. Harrington, Associate Professor, Medical Entomology, Department of Entomology, College of Agriculture and Life Sciences, Cornell University. She has been advising our graduate student on the entomological studies on potential mosquito vectors in New York State as a part of a risk assessment study on WNV. She will continue to provide supervision on the proposed entomological studies. Training Opportunities: Ms. Christine Decarlo. She successfully completed all the requirements for her program PhD graduate student at Cornell. Her PhD thesis was based on the project. Sabrina Benteftifa. She is an undergraduate at Cornell. She has been helping in the laboratory studies with emphasis on collection of blood samples from agricultural animals. TARGET AUDIENCES: The proposed studies are expected to provide the necessary information regarding the factors associated with the risk of maintenance reservoirs in agricultural settings so that intervention strategies can be devised. This information will be useful to farmers, extension personnel, and residence of the targeted agricultural niches to help development of educational materials related to the risk of the WNV and the strategies to mitigate the associated adverse consequences. We hope to work with the educational institutes and extension personnel in the agricultural niches to develop recommendations regarding approaches to mitigate the risk of WNV in NYS and hopefully extrapolating the results to other areas in the country to control and eradicate this disease. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Using the resources made available through this grant we were able to develop a TR-PCR test to detect the presence of the WNV in mosquitoes capered in the targeted agricultural niches. We continued to demonstrate that there is no evidence of a virus circulation among the captured mosquitoes in the targeted areas in New York. So far all the mosquitoes that were tested with developed RT-PCR were negative for the presence of the virus. To address our objectives of examining evidence of exposure to the virus among agricultural animals, we tested serum samples collected from cows in the targeted agricultural niches for the presence of antibodies against the WNV. All the samples were negative. The results on these samples continued to date support the premise that, although cows are reported to be a potential reservoir for WNV in other part of the world they are not in the US. We will continue to collect samples from the agricultural animals and test them for the presence of antibodies to the WNV. Samples were collected from wildlife (raccoon) and tested for antibodies against the WNV. The observed seroconversion among raccoons is suggestive of the potential role for the raccoon as a reservoir for the WNV in the agricultural niches. We will continue to collect samples from the wildlife and tested for the presence of antibodies.

Publications

• DeCarlo CH, Ziegler PE, Glaser AL, Szonyi B, Mohammed HO. Factors led to evolution of endemic foci for West Nile Virus in New York State. International Symposia on Veterinary Epidemiology and Economics (ISVEE) proceedings, ISVEE 12: Proceedings of the 12th Symposium of the International Society for Veterinary Epidemiology and Economics, Durban, South Africa, August 2009.
• DeCarlo CH, Glaser AL, Szonyi B, Ahmed NI, and Mohammed HO. The risk of West Nile Virus among crows in New York State. Proceeding of the International Conference in ASZWM; Kuala Lumpur, Malaysia, August 2010.
• DeCarlo CH, Clark AB, McGowan KJ, Ziegler PE, Glaser AL, Szonyi B, Mohammed HO. Factors Associated With the Risk of West Nile Virus Among Crows in New York State. Zoonoses Public Health; 2010 (Epub ahead of printing).

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: The objective of our proposed studies was to use a tiered approach to collect data to assess the factors which might potentially place agricultural animals at a greater risk of infection of WNV. This investigation intends to explore the range of agricultural animals wildlife reservoirs of WNV frequently found in agricultural niches. In addition, we hope to identify the spectrum of mosquito vectors in this ecosystem. By examining findings within the context of each farm ecosystem we hope to identify ecological and management factors that could then be applied to future strategies to mitigate risk. During the reporting period we were able to collect blood samples from cattle and raccoons and tests the samples for evidence of exposure to the West Nile Virus. We also collected mosquitoes in the agricultural ecosystem and tested for the presence of the virus using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The RT-PCR assay was developed during this period and validity for its accuracy of detection of the WNV in a pool of infected mosquito samples. We also used the assay for testing mosquitoes captured in these areas for infection with the WNV. Mosquitoes collected from these agricultural niches tested negative for the presence of the WNV. It is also worth noted that we collected the samples in early fall (October) and there were no reported cases of human WNV infection from that area during this period. All the agricultural animal samples (63 cows and 3 lamas) were serologically negative for evidence of exposure to the WNV. Twenty percent of the samples collected from raccoons were tested positive in the serological test. The finding in these studies to date have partially contributed to our knowledge about the ecology of this virus in the targeted agricultural niches and showed cattle are unlikely to be reservoir to the virus in this agricultural niches. PARTICIPANTS: Hussni O. Mohammed, Professor of Epidemiology, Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University: He designed the proposed studies, supervised the graduate student, Ms. Christine DeCarlo, whose this project is a part of her PhD training program. Amy L. Glaser, COPI, Senior Research Associate, Assistant Director-Virology, Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University. She is supervising the molecular and serological activities that are being carried out in the proposed studies. Laura Bigler: Wildlife Expert and Research Associate at the Department of Population Medicine & Diagnostic Sciences, College of Veterinary Medicine, Cornell University. She has been supervising the field studies on the wildlife and collecting the raccoon samples. Laura C. Harrington, Associate Professor, Medical Entomology, Department of Entomology, College of Agriculture and Life Sciences, Cornell University. She has been advising our graduate student on the entomological studies on potential mosquito vectors in New York State as a part of a risk assessment study on WNV. She will continue to provide supervision on the proposed entomological studies. Training Opportunities: Ms. Christine Decarlo: She is a PhD-graduate student at Cornell and the project represents a great part of her thesis research. She is overseeing the entire field and laboratory activates in the proposed studies. Ms. Jennifer Lynn Rokhaser: She is a veterinary student at Cornell. She has been helping in the field studies with emphasis on collection of blood samples from agricultural animals. TARGET AUDIENCES: The proposed studies are expected to provide the necessary information regarding the factors associated with the risk of maintenance reservoirs in agricultural settings so that intervention strategies can be devised. This information will be useful to farmers, extension personnel, and residence of the targeted agricultural niches to help development of educational materials related to the risk of the WNV and the strategies to mitigate the associated adverse consequences. We hope to work with the educational institutes, extension personnel, and agricultural bodies in the agricultural niches to develop recommendations regarding approaches to mitigate the risk of WNV in NYS and hopefully extrapolating the results to other areas in the country to control and eradicate this disease. PROJECT MODIFICATIONS: Based on our preliminary findings to date we are planning to expand our study area to include other niches that are known to have sporadic human cases of WNV. These niches are located in areas within NYS where we have a well-established disease control and research program which includes collaboration with local stakeholders and data collection examining the risk of zoonotic diseases that are associated with wildlife in Nassau and Suffolk counties. There are active foci of the disease in these counties.

Impacts
Using the resources made available through this grant we were able to develop a TR-PCR test to detect the presence of the WNV in mosquitoes capered in the targeted agricultural niches. So far all the mosquitoes that were tested with developed RT-PCR were negative for the presence of the virus. We will continue to collect mosquitoes from the targeted agricultural niches and test them. We tested serum samples collected from cows in the targeted agricultural niches for the presence of antibodies against the WNV and all the samples were negative. The results on these samples to date support the premise that, although cows are reported to be a potential reservoir for WNV in other part of the world they are not in the US. We will continue to collect samples from the agricultural animals and test them for the presence of antibodies to the WNV. Samples were collected from wildlife (raccoon) and tested for antibodies against the WNV. The observed seroconversion among raccoons is suggestive of the potential role for the raccoon as a reservoir for the WNV in the agricultural niches. We will continue to collect samples from the wildlife and tested for the presence of antibodies.

Publications

• No publications reported this period