Sequential isolation of rotavirus from individual calves

Area of Science:

• Veterinary Medicine
• Virology
• Animal Science

Background:

• Neonatal calf diarrhea poses significant economic challenges in beef cattle farming.
• Japanese indigenous beef cattle breeds may have unique susceptibilities to enteric pathogens.

Purpose of the Study:

• To investigate the cause of a neonatal calf diarrhea outbreak on a Japanese beef cattle breeding farm.
• To identify the causative agent and understand its epidemiological dynamics.

Main Methods:

• Isolation and identification of viruses from fecal samples of affected calves using cell cultures.
• Detection of bovine rotavirus through serological and neutralization tests.
• Monitoring viral shedding and persistence in calves post-outbreak.

Main Results:

• Bovine rotavirus was identified as the causative agent in 90.7% of affected calves.
• High isolation rates of rotavirus from diarrhea specimens (83.5%) confirmed its prevalence.
• Rotavirus was re-isolated from some calves over several weeks, indicating potential persistence or re-infection.
• Antigenic differences were observed between early and later viral isolates, suggesting strain variation.

Conclusions:

• Bovine rotavirus is a primary cause of neonatal diarrhea in this Japanese beef cattle herd.
• The study highlights the potential for persistent rotavirus infections or re-infection with different strains.
• Further research into rotavirus epidemiology and antigenic diversity in cattle is warranted.