A team of scientists at Colorado State University, led by veterinary postdoctoral fellow Dr. Anna Fagre, has detected the RNA of the Zika virus in African bats in the wild. RNA or ribonucleic acid is a molecule that plays a central role in the function of genes.
According to Fagre, the new research is the first in science. It is also the first time scientists have published a study on the detection of Zika virus RNA in any free bat.
The findings have ecological implications and raise questions about how bats are exposed to the Zika virus in the wild. The study was recently published in Scientific reports.
Fagre, a researcher at the CSU Center for Vector Infectious Diseases Center, said that while other studies have shown that bats are susceptible to the Zika virus in controlled experimental environments, detection of nucleic acid in wild bats indicates that they are infected or exposed naturally through the bite of infected mosquitoes.
“This provides more information about the ecology of flaviviruses and suggests that much remains to be learned about the range of flavivirus hosts, such as the Zika virus,” he said. Flaviviruses include viruses such as West Nile and dengue and cause various diseases in humans.
CSU associate professor Rebekah Kading, lead author of the study, said she, Fagre and the research team wanted to learn more about the potential reservoirs of the Zika virus through the project.
The team used 198 bat samples collected in the Zika forest and surrounding areas of Uganda and confirmed the Zika virus in four bats representing three species. The samples used in the study date back to 2009 from different parts of Uganda, years before the major outbreaks of the Zika virus from 2015 to 2017 in North and South America.
“We knew flaviviruses were circulating in bats and we had serological tests for them,” Kading said. “We were wondering: were the bats exposed to the virus or could they have some involvement in the transmission of the Zika virus?”
The virus detected by the team in bats was more closely related to the Asian lineage virus Zika, the strain that caused the epidemic in the Americas after outbreaks in Micronesia and French Polynesia. The first detection of the Asian Zika virus in Africa was in late 2016 in Angola and Cape Verde.
“Our positive samples, which are more related to the Asian Zika lineage virus, came from bats sampled from 2009 to 2013,” Fagre said. “This could mean that the strain of the Asian lineage of the virus has been present on the African continent for longer than we originally thought, or it could mean that there was a good viral evolution and genomic changes that occurred in the Zika virus of the African lineages were not aware of it before. “
Fagre said the relatively low prevalence of Zika virus in bat samples indicates that bats may be incidental hosts of Zika virus infection, rather than amplified hosts or deposit hosts.
“Given that these results come from a single cross-sectional study, it would be risky and premature to draw conclusions about the ecology and epidemiology of this pathogen, based on our study,” he said. “Studies like this only tell a part of the story.”
The research team also created a unique assay for the study, focusing on a specific molecular component that flaviviruses possess called flavivirus subgenomic RNA, sfRNA. Most scientists looking for evidence of Zika virus infection in humans or animals use PCR, Polymerase chain reaction, to identify pieces of genomic RNA, the nucleic acid that results in protein production, Fagre said.
Kading said his team will continue research to try to learn more about how long these RNA fragments persist in tissues, which will allow them to get closer when these bats were infected with the Zika virus.
“There’s always a concern about zoonotic viruses,” he said. “The potential for another outbreak is there and it may be silent for a while. We know that in the Zika forest, where the virus was first found, the virus is found in non-human primates. There are still some questions with that as well. “I don’t think the Zika virus is gone forever.”
Anna C. Fagre et al, flavivirus subgenomic RNA (sfRNA) associated with the Asian Zika virus lineage identified in three species of Ugandan bats (family Pteropodidae), Scientific reports (2021). DOI: 10.1038 / s41598-021-87816-5
Colorado State University
Citation: Researchers make first discovery of Zika RNA virus in African bats released (2021, June 2) retrieved June 2, 2021 at https://medicalxpress.com/news/2021-06-first- ever-discovery-zika- virus-rna.html
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