Risk factors associated with herd-level exposure of cattle in Nebraska, North Dakota, and South Dakota to bluetongue virus

Alice L. Green USDA:Animal and Plant Health Inspection Service (APHIS):Veterinary Services (VS), Centers for Epidemiology and Animal Health,2150 Centre Ave, Bldg B, Mail Stop 2E7, Fort Collins, CO 80526-8117.

Search for other papers by Alice L. Green in
Current site
Google Scholar
PubMed
Close
 MS, DVM
,
David A. Dargatz USDA:Animal and Plant Health Inspection Service (APHIS):Veterinary Services (VS), Centers for Epidemiology and Animal Health,2150 Centre Ave, Bldg B, Mail Stop 2E7, Fort Collins, CO 80526-8117.

Search for other papers by David A. Dargatz in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Edward T. Schmidtmann USDA Agricultural Research Service, 1000 E University Ave, Department 3354, Laramie, WY 82071.

Search for other papers by Edward T. Schmidtmann in
Current site
Google Scholar
PubMed
Close
 PhD
,
Marco V. Herrero USDA:Animal and Plant Health Inspection Service (APHIS):Veterinary Services (VS), Centers for Epidemiology and Animal Health,2150 Centre Ave, Bldg B, Mail Stop 2E7, Fort Collins, CO 80526-8117.
Present address is the Tropical Disease Research Program, School of Veterinary Medicine, Universidad Nacional, Apartado 304-3000, Heredia, Costa Rica.

Search for other papers by Marco V. Herrero in
Current site
Google Scholar
PubMed
Close
 PhD
,
Ann H. Seitzinger USDA:Animal and Plant Health Inspection Service (APHIS):Veterinary Services (VS), Centers for Epidemiology and Animal Health,2150 Centre Ave, Bldg B, Mail Stop 2E7, Fort Collins, CO 80526-8117.

Search for other papers by Ann H. Seitzinger in
Current site
Google Scholar
PubMed
Close
 PhD
,
Eileen N. Ostlund USDA:APHIS:VS, National Veterinary Services Laboratories, 1800 Dayton Ave, Ames, IA 50010.

Search for other papers by Eileen N. Ostlund in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Bruce A. Wagner USDA:Animal and Plant Health Inspection Service (APHIS):Veterinary Services (VS), Centers for Epidemiology and Animal Health,2150 Centre Ave, Bldg B, Mail Stop 2E7, Fort Collins, CO 80526-8117.

Search for other papers by Bruce A. Wagner in
Current site
Google Scholar
PubMed
Close
 PhD
,
Kathryn M. Moser USDA:APHIS:VS, National Veterinary Services Laboratories, 1800 Dayton Ave, Ames, IA 50010.

Search for other papers by Kathryn M. Moser in
Current site
Google Scholar
PubMed
Close
 MS
,
Nora E. Wineland USDA:Animal and Plant Health Inspection Service (APHIS):Veterinary Services (VS), Centers for Epidemiology and Animal Health,2150 Centre Ave, Bldg B, Mail Stop 2E7, Fort Collins, CO 80526-8117.

Search for other papers by Nora E. Wineland in
Current site
Google Scholar
PubMed
Close
 DVM, MS
, and
Thomas E. Walton USDA:Animal and Plant Health Inspection Service (APHIS):Veterinary Services (VS), Centers for Epidemiology and Animal Health,2150 Centre Ave, Bldg B, Mail Stop 2E7, Fort Collins, CO 80526-8117.

Search for other papers by Thomas E. Walton in
Current site
Google Scholar
PubMed
Close
 DVM, PhD, ScD

Abstract

Objective—To evaluate herd-level risk factors for seropositive status of cattle to 1 or more bluetongue viruses.

Animals—110 herds of cattle in Nebraska, North Dakota, and South Dakota.

Procedure—Blood samples were collected before and after the vector season. Samples were tested for antibodies against bluetongue virus by use of a commercially available competitive ELISA. Factors evaluated included descriptors of geographic location and management practices. Trapping of insect vectors was conducted to evaluate vector status on a subset of 57 operations. A multivariable logistic regression model was constructed to evaluate associations.

Results—For the full data set, altitude and latitude were associated with risk of having seropositive cattle (an increase in altitude was associated with an increase in risk, and a more northerly location was associated with a decrease in risk of a premise having seropositive cattle). Import of cattle from selected states was associated with an increase in risk of having seropositive cattle. From the subset of herds with data on vector trapping, altitude and latitude were associated with risk of having seropositive cattle, similar to that for the full model. However, commingling with cattle from other herds was associated with a decrease in risk of seropositivity.

Conclusions and Clinical Relevance—Findings reported here may be useful in generating additional hypotheses regarding the ecologic characteristics of bluetongue viruses and other vector-borne diseases of livestock. Sentinel surveillance programs are useful for documenting regionalization zones for diseases, which can be beneficial when securing international markets for animals and animal products. (Am J Vet Res 2005;66:853–860)

Abstract

Objective—To evaluate herd-level risk factors for seropositive status of cattle to 1 or more bluetongue viruses.

Animals—110 herds of cattle in Nebraska, North Dakota, and South Dakota.

Procedure—Blood samples were collected before and after the vector season. Samples were tested for antibodies against bluetongue virus by use of a commercially available competitive ELISA. Factors evaluated included descriptors of geographic location and management practices. Trapping of insect vectors was conducted to evaluate vector status on a subset of 57 operations. A multivariable logistic regression model was constructed to evaluate associations.

Results—For the full data set, altitude and latitude were associated with risk of having seropositive cattle (an increase in altitude was associated with an increase in risk, and a more northerly location was associated with a decrease in risk of a premise having seropositive cattle). Import of cattle from selected states was associated with an increase in risk of having seropositive cattle. From the subset of herds with data on vector trapping, altitude and latitude were associated with risk of having seropositive cattle, similar to that for the full model. However, commingling with cattle from other herds was associated with a decrease in risk of seropositivity.

Conclusions and Clinical Relevance—Findings reported here may be useful in generating additional hypotheses regarding the ecologic characteristics of bluetongue viruses and other vector-borne diseases of livestock. Sentinel surveillance programs are useful for documenting regionalization zones for diseases, which can be beneficial when securing international markets for animals and animal products. (Am J Vet Res 2005;66:853–860)

Advertisement