Using wild white-tailed deer to detect eastern equine encephalitis virus activity in Maine.

This research studied a sample of white-tailed deer in Maine to detect the activity of Eastern Equine Encephalitis Virus (EEEV), discovering that 7.1% of the deer had EEEV antibodies. The findings suggest that testing deer sera can be a helpful tool in tracking EEEV activity in North America.

Methodology

• The researchers collected serum from 226 wild white-tailed deer for the purpose of this study.
• The presence of Eastern Equine Encephalitis Virus (EEEV) antibodies was screened in the collected serum using plaque reduction neutralization tests.
• Along with the serum tests, the team also tested 150 harvested deer brain samples to detect the presence of EEEV RNA.
• Detailed geographical location data was recorded for each deer whose serum was tested, tracking where the deer had been harvested.

Findings

• The results showed that 7.1% of the deer serum samples contained EEEV antibodies, marking the first time such antibodies have been detected in white-tailed deer populations in Maine.
• The highest percentage of EEEV positive serum samples (19%) was found in Somerset County, marking the first instance of EEEV activity in that region.
• EEEV RNA, however, was not detected in any of the harvested deer brain samples.
• Rather than signaling a lack of EEEV in the deer population, the lack of RNA in the brain samples indicates to the researchers that screening deer brains may not be an efficient method of detecting EEEV activity.
• No significant geographical clustering was found in the locations of the antibody-positive serum samples.
• The researchers also found a slightly increased likelihood for deer with EEEV antibodies to have been harvested in non-forested areas as compared to forested areas.

Conclusions

• Based on the results of this study, the researchers conclude that screening free-ranging deer serum for EEEV antibodies has potential as an effective tool for detecting EEEV activity in North America.
• The method could be especially useful for areas and populations where EEEV has not previously been detected or is considered novel.
• The researchers suggest that screening studies should possibly focus more on deer harvested from non-forested areas, given the slightly increased likelihood of finding EEEV antibodies among those animals.