Newly Identified Rotavirus Genotype in Mexico Raises Zoonotic Concerns

Medical News: Rotavirus is a leading cause of severe diarrhea among young animals and humans alike. Known as rotavirus species A (RVA), this virus primarily affects gastrointestinal health, causing notable economic losses in farming due to disease and death among animals. While rotavirus has been widely studied in livestock and humans, it remains understudied in rabbits, despite rabbits being known carriers. Recently, researchers identified a novel rotavirus genotype, G3 P[8], in rabbits from a commercial farm in Mexico. This genotype, typically found in humans, is unprecedented in rabbits, raising concerns about possible interspecies transmission.


Newly Identified Rotavirus Genotype in Mexico Raises Zoonotic Concerns

This Medical News report will examine the groundbreaking study conducted by scientists from several institutions, including the Universidad Autónoma del Estado de México, Universidad Nacional Autónoma de México, and the Universidad Autónoma Benito Juárez de Oaxaca, focusing on their findings, the methodology they used, and what this could mean for animal and human health.
 
Background and Relevance of Rotavirus in Rabbits
Rotavirus infections in animals are usually host-specific, meaning certain genotypes commonly affect particular species. For instance, genotype G3 with P[14] or P[22] is often seen in rabbits, while genotypes like P[8] are primarily found in humans. Despite occasional cross-species transmission events, seeing a combination like G3 P[8] in rabbits is rare, suggesting a unique case of possible zoonotic transfer, where the virus jumps between species.
 
Rotavirus infections in rabbits, particularly young ones, can have substantial economic consequences. These infections often lead to diarrhea, dehydration, and malnutrition, impacting growth and survival rates on farms. The introduction of a human-associated rotavirus strain into rabbits could signify broader environmental or health issues, as rabbits may have come into contact with human waste or contaminated sources, exposing them to viral strains they don’t typically encounter.
 
Key Study Findings
In the study, researchers collected samples from rabbits at a large farm in Mexico that had experienced an outbreak of diarrhea. They used molecular techniques to analyze viral RNA from six positive cases, identifying the G3 P[8] genotype in one sample, named C-3/15. Notably, this strain displayed a genetic closeness to human strains, with the VP4 and VP7 genes showing significant similarity to human rotaviruses, a discovery that has not previously been documented in rabbits.
 
Detection and Analysis of the Virus
To detect and characterize the rotavirus strain, scientists used several advanced techniques:
-RNA Extraction and PCR: Researchers extracted viral RNA from rabbit tissue samples and used RT-PCR to amplify the VP4 and VP7 genes, which are critical for identifying the rotavirus genotype. This approach helped reveal the str ain’s unique G3 P[8] genotype, previously undetected in rabbits.
 
-Phylogenetic Analysis: The team employed phylogenetic analysis to compare the VP4 and VP7 gene sequences of the rabbit strain with known rotavirus strains from other species. This analysis confirmed that the VP4 gene of the C-3/15 strain was closely related to human strains, particularly one from the USA. The VP7 gene also shared a close relation with human strains, further supporting the hypothesis of cross-species transmission.
 
-Genotyping Tool: Researchers utilized an automated genotyping tool, RotaC 2.0, to identify the strain’s genotype, verifying that C-3/15 belongs to the P[8] genotype, which is almost exclusively associated with humans.
 
Significance of Findings on Cross-Species Transmission
The detection of a human-associated rotavirus strain in rabbits is unusual and raises the possibility of interspecies transmission. This event could have occurred due to contaminated feed or water sources, suggesting that the rabbits might have ingested virus particles shed by humans. This study highlights how viruses can cross species barriers, often resulting in genetic reassortment or mutations that may affect how the virus behaves in a new host.
 
Interspecies transmission of rotavirus is rare but not unheard of. For example, previous studies have documented rotavirus strains in animals like pigs and dogs that resemble human strains. However, this is the first report of a G3 P[8] strain, typically found in humans, in a rabbit. The researchers speculate that this could indicate a breakdown in sanitary measures or suggest that the farm's rabbits were somehow exposed to human waste, emphasizing the need for better biosecurity practices on animal farms.
 
Broader Implications and the Potential for Human-Animal Disease Transmission
The implications of this finding extend beyond the rabbit farming industry. Cross-species transmission of rotavirus is a potential public health issue, especially if animals act as reservoirs for viral strains that could eventually infect humans. The presence of human strains in animal populations could lead to the development of new rotavirus variants through genetic reassortment, potentially resulting in strains that affect both animals and humans.
 
This particular finding is noteworthy because it indicates that animal husbandry practices could inadvertently facilitate the spread of human pathogens to animals and vice versa. If similar cross-species transmission events continue, there could be an increased risk of zoonotic infections. The G3 P[8] strain’s adaptation to a new host could lead to mutations that allow it to spread more effectively within the rabbit population, possibly creating a reservoir for human reinfection in the future.
 
Conclusion
The discovery of the G3 P[8] rotavirus genotype in Mexican rabbits adds to the growing evidence of interspecies viral transmission, particularly involving strains typically associated with humans. This incident illustrates the importance of stringent hygiene and management practices in animal farming to prevent the spread of zoonotic diseases. Moreover, it sheds light on how easily viruses can adapt to new hosts, raising concerns for public health and animal farming industries alike.
 
These findings call for further research into the extent and frequency of human rotavirus strains appearing in animals, especially in commercial farming settings. This research could help in developing preventive measures to minimize the risk of zoonotic transmissions. Future studies might focus on identifying potential vectors or environmental factors that facilitate these cross-species transmissions, ensuring that both animals and humans are protected from emerging infectious diseases.
 
The study findings were published in the peer-reviewed journal: Viruses.
https://www.mdpi.com/1999-4915/16/11/1729
 
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