Among the foreign animal diseases posing potential threats to U.S. herds, we don’t often hear about Rift Valley Fever. However, if the mosquito-borne virus did find its way to our shores, it could spread and cause significant damage in cattle herds.
According to a new report from the U.S. Centers for Disease Control and Prevention (CDC), white-tailed deer (Odocoileus virginianus) are susceptible to the disease, meaning they could serve as sentinel animals for epidemiologic studies, and also could harbor the virus and play a role in its ability to spread. Unlike some other foreign animal diseases of concern, such as foot and mouth disease (FMD), Rift Valley Fever is zoonotic, with outbreaks in its natural range in Sub-Saharan Africa a significant human-health challenge.
In this study, scientists housed five young deer in a Biosafety Level 3 facility. They inoculated four of the deer with the Rift Valley Fever Virus (RVFV) used a sham injection with the fifth deer, which served as a control. They monitored the deer for clinical signs, conducted gross pathology exams and used qRT-PCR to determine virus RNA loads. Two of the deer died within a few days of inoculation, while the other two survived through the trial but were confirmed infected with RVFV. The control animal also contracted the disease, as confirmed through gross pathology and PCR analysis, suggesting horizontal transmission of the virus. The researchers concluded that white-tailed deer are highly susceptible to RVFV infection, which caused hepatic necrosis and hemorrhage.
With white-tailed deer widely distributed across the United States, and several U.S. mosquito species capable of serving as RVFV vectors, the researchers note they could serve as sentinel animals for disease surveillance, and also could provide a reservoir for propagating the virus should it become established here.
Read more from the CDC report.