Blue jays and west nile virus

In the laboratory, the cloacal and nasopharyngeal areas were swabbed from each bird individually with standard cotton applicators. The kidneys of each of these birds were harvested after evisceration, and specimen samples were put into individual vials. The time of death of the field-collected crows and blue jays could not be ascertained by the collectors but was generally believed to be within 48 hours postmortem. Decomposed carcasses were not accepted for testing. At the end of the reaction, the amplification plot generated was viewed on a log scale with the system's default threshold.

After the RT-PCR preliminary assays on the kidney samples were conducted, of the avian kidney samples that had tested positive for WNV were randomly selected for further investigation; 61 of the samples were from crows and 39 were from blue jays. The corresponding cloacal and nasopharyngeal swab samples of these positive birds were additionally tested for WNV. In the test, each cloacal or nasopharyngeal swab sample was thoroughly mixed in the BA-1 medium by vortexing.

As with the kidney samples, a Statistical analyses of the results from the tests were performed by using the SPSS for Windows release The positive kidney samples had various C T values the cycle at which the fluorescence rises appreciably above the background level , which ranged between When all of the positive kidney samples were divided into 3 categories of "high" C T Because no meaningful difference was seen between the test results of the crows and the blue jays in these categories, the data from both bird species were combined in our analyses.

None of the cloacal or nasopharyngeal swab samples were in the high-positive group. Seventy-seven percent of the cloacal and nasopharyngeal swab samples were either in the low-positive or negative categories. Contrary to earlier findings 8 in which oropharyngeal swabs were more sensitive than cloacal swabs by using the VecTest antigen-capture assay, we found no appreciable difference in our study between the C T values of the cloacal and nasopharyngeal swab samples.

The correlation and linear regression analyses indicate that both the cloacal and nasopharyngeal swab samples showed a smaller proportion of the positive specimen than did the kidney testing.

Although viral amounts in the samples were not quantified, virus was detected in the cloacal and nasopharyngeal samples, usually only when the viral load in the kidney samples from the birds was high. The brain is reportedly the most sensitive organ to detect WNV in American crows 5. Other internal organs such as liver, kidney, spleen, heart, and lungs are also useful to detect viruses.

However, because these organs can only be obtained through necropsy, easier, but equally sensitive, methods of sample collection are needed. Earlier research results on the value of testing cloacal and nasopharyngeal samples have not been consistent, reflecting differences in sampling methods. High viral infections in the bird kidney result in positive swab specimens, however, lower viral amounts may not.

We did not determine if the reduced amount of viral RNA in the swab samples could have been due to inactivation during the 4 months of storage after sampling. As with most viruses, there is no specific treatment for West Nile Virus.

Some animals may require supportive care to survive. Animals with milder symptoms are more likely to recover than those showing severe neurological signs. Pennsylvania has a West Nile Virus control program that includes testing mosquitoes and dead birds for the disease.

The state also monitors for human and horse cases of WNV to determine the distribution of the disease throughout PA. Disease transmission can be prevented with mosquito population control. People should use insect repellant and wear long sleeves and long pants to avoid mosquito bites when spending time outside. People should also drain standing water around their houses in order to minimize mosquito breeding grounds.

There is currently a vaccine available for horses. Bureau of Animal Health and Diagnostic Service. West Nile Virus brochure. West Nile Virus. McLean, R. Arboviruses in birds. Pages in N.

Thomas, D. Hunter, and C. Atkinson, editors. Infectious diseases of wild birds. In humans, WNV has been transmitted in a small number of cases by organ transplants, blood transfusions, and breast milk.

Direct contact between people and animals is not a known source of infection to humans. Areas of standing water mosquitos lay eggs in include wheelbarrows, pool covers, birdbaths, gutters and any other place water can collect. Pool and pond water can be treated with mosquito dunks, which contain a natural bacterial product that kills mosquito larvae.

Mosquitoes should be prevented from entering the home through open windows and doors or broken screens. Personal preventive measures include limiting skin exposure by wearing shoes, socks, long sleeves, and pants, especially during times when mosquitoes are most active like dusk.

Exposed skin can be protected with mosquito repellent. Local county health departments are responsible for general mosquito control measures in New York. This vaccine is also used in captive birds. Veterinary surveillance for encephalitis in horses is encouraged. West Nile Virus.

Abstract Blue jays Cyanocitta cristata are an effective indicator species for West Nile virus WNV and may be regionally important in surveillance efforts. Publication types Research Support, Non-U. Gov't Research Support, U.

Gov't, Non-P.