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ABSTRACT: Semen from an apparently healthy 4-year-old American Quarter Horse was submitted to the National Veterinary Services Laboratories for Equine arteritis virus isolation. Visual inspection of the semen sample upon arrival noted it was unusually yellow in color. The semen sample was inoculated onto cell monolayers, and cytopathic effect was observed 5 days postinoculation. The resultant isolate tested negative for Equine arteritis virus, and was subsequently identified as Equine rhinitis A virus. Equine rhinitis A virus has been isolated from horse urine, but has not been described in stallion semen. The present study documents the isolation of Equine rhinitis A virus from stallion semen that was likely contaminated with urine at the time of collection.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 05/2012; 24(4):801-3. · 1.21 Impact Factor
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ABSTRACT: Coxiella burnetii is an obligate intracellular bacterium that is responsible for the zoonotic disease Q fever. The distribution of this agent is worldwide except for New Zealand, and infection can be asymptomatic in both human beings and animals. Chronic exposures can produce abortions, stillbirths, and infertility issues in animals and endocarditis in human beings. A commercial enzyme-linked immunosorbent assay (ELISA) kit marketed in the European Union was purchased to compare C. burnetii antibody detection methods. The current study examined the agreement of ELISA and complement fixation results in over 668 diagnostic ruminant sera submitted to the National Veterinary Services Laboratories for Q fever serologic testing. The majority of combined sera (548) were negative on both tests. Fifty-seven of the combined sera were positive on both tests. There were 45 combined sera with low complement fixation titers at 1:10 and negative ELISA results. The results were surprising given the expectations that ELISA methods, by nature, amplify detection of antibody-antigen interactions leading to higher sensitivity. Potential mechanisms for these discrepant results are discussed.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 03/2012; 24(2):379-82. · 1.21 Impact Factor
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ABSTRACT: In November 2004, tissues were collected from a hunter-killed white-tailed deer in St. Mary Parish, Louisiana. Bluetongue virus (BTV) was isolated from the tissues; however, the isolate could not be identified as any of the US domestic serotypes. Subsequent testing by virus neutralization using serotype-specific antiserum tentatively identified the isolate as BTV serotype 1 (BTV-1), which had not previously been found in the United States. Primers were designed based on the sequence of an outer capsid protein gene of a South African BTV-1 strain. Reverse transcription-polymerase chain reaction testing with the BTV-1 primers and product sequencing confirmed the Louisiana isolate as BTV-1. This is the first report of BTV-1 in the United States.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 08/2006; 18(4):398-401. · 1.21 Impact Factor
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ABSTRACT: To evaluate herd-level risk factors for seropositive status of cattle to 1 or more bluetongue viruses.
110 herds of cattle in Nebraska, North Dakota, and South Dakota.
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.
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.
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.
American Journal of Veterinary Research 06/2005; 66(5):853-60. · 1.27 Impact Factor
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Ann H Davidson,
Josie L Traub-Dargatz,
Racquel M Rodeheaver, Eileen N Ostlund,
Douglas D Pedersen,
Ron G Moorhead,
Joe B Stricklin,
Renee D Dewell,
Susan D Roach,
Rachel E Long,
Sara J Albers,
Robert J Callan,
M D Salman
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ABSTRACT: To compare neutralizing antibody response between horses vaccinated against West Nile virus (WNV) and horses that survived naturally occurring infection.
Cross-sectional observational study.
187 horses vaccinated with a killed WNV vaccine and 37 horses with confirmed clinical WNV infection.
Serum was collected from vaccinated horses prior to and 4 to 6 weeks after completion of an initial vaccination series (2 doses) and 5 to 7 months later. Serum was collected from affected horses 4 to 6 weeks after laboratory diagnosis of infection and 5 to 7 months after the first sample was obtained. The IgM capture ELISA, plaque reduction neutralization test (PRNT), and microtiter virus neutralization test were used.
All affected horses had PRNT titers > or = 1:100 at 4 to 6 weeks after onset of disease, and 90% (18/20) maintained this titer for 5 to 7 months. After the second vaccination, 67% of vaccinated horses had PRNT titers > or = 1:100 and 14% had titers < 1:10. Five to 7 months later, 33% (28/84) of vaccinated horses had PRNT titers > or = 1:100, whereas 29% (24/84) had titers < 1:10. Vaccinated and clinically affected horses' end point titers had decreased by 5 to 7 months after vaccination.
A portion of horses vaccinated against WNV may respond poorly. Vaccination every 6 months may be indicated in certain horses and in areas of high vector activity. Other preventative methods such as mosquito control are warranted to prevent WNV infection in horses.
Journal of the American Veterinary Medical Association 02/2005; 226(2):240-5. · 1.79 Impact Factor
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ABSTRACT: A traditional nested reverse transcription-polymerase chain reaction (RT-PCR) assay specific for eastern equine encephalomyelitis (EEE) virus was designed to multiplex with a previously described West Nile (WN) virus nested RT-PCR assay. Differentiation of EEE and WN was based on base pair size of the amplified product. One hundred fifty-seven mammalian and avian brain tissues were tested by EEE/WN nested multiplex RT-PCR, EEE nested RT-PCR, and WN nested RT-PCR, and results were compared with other diagnostic test results from the same animals. Serological and virus isolation testing confirmed the results of the multiplex PCR assay. When compared with cell culture virus isolation, the multiplex assay was shown to be more sensitive in detecting the presence of EEE or WN virus in brain tissues. The multiplex assay was shown to be sensitive and specific for North American EEE and WN and provided a rapid means of identifying both viruses in brain tissues. No apparent sacrifice in sensitivity was observed in the multiplex procedure compared with the individual EEE and WN nested RT-PCR assays. Data collected from an additional 485 multiplex RT-PCR tests conducted during the summer and fall of 2002 further support the validity of the procedure.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 10/2003; 15(5):488-93. · 1.21 Impact Factor
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ABSTRACT: Bovine sera from northeastern states (Connecticut, Delaware, Maine, Maryland, Massachusetts, New York, Pennsylvania, Vermont, and West Virginia), north central states (Indiana, Illinois, Iowa, Kentucky, Michigan, Minnesota, North Dakota, Ohio, South Dakota, and Wisconsin), Virginia, Alaska, and Hawaii were examined for the presence of neutralizing antibodies to Cache Valley (CV), Lokern (LK), Main Drain (MD), Northway (NW), and Tensaw (TS) viruses. Microneutralization tests were performed using Vero cells. Ninety percent inhibition of the virus at a 1:10 serum dilution was considered positive for the presence of specific antibody. Sera having antibody to more than one virus were titrated from 1:10 to 1:640. The results indicated that 4-28% of the cattle per region had specific antibodies to CV virus. Neutralizing antibodies to NW, LK, and TS viruses were also detected, indicating possible exposure to these Bunyamwera serogroup viruses along with CV virus. Antibody titers measured against NW virus were very similar to those against CV virus. Antibodies to MD virus were present in low levels in bovine sera from Illinois, Maryland, and Ohio. Cattle from Alaska had only antibodies to NW virus. Antibodies to Bunyamwera serogroup viruses were not observed in sera from Hawaii.
The American journal of tropical medicine and hygiene 08/2002; 67(1):119-22. · 2.59 Impact Factor
