Arboviruses recovered from sentinel livestock in northern Australia.

This research study documents the recovery and identification of over 700 arboviruses from sentinel livestock near Darwin, Australia between 1981 and 1987. The identified viruses belong to several groups, with four having been isolated solely in Darwin and ten not found elsewhere in Australia.

Study Methodology and Findings

• The research study was conducted in northern Australia near Darwin and spanned over six years, starting from 1981 and concluding in 1987.
• A significant number of arboviruses, over 700, were successfully recovered from sentinel livestock’s blood. Sentinel livestock are animals used in surveillance to detect the presence of certain diseases or pathogens within a particular area.
• The livestock included various animals such as sheep, goats, swamp buffalo (Bubalus bubalis), horses, and particularly cattle, from which a majority of the samples were obtained.

Arboviruses Classification

• All the isolates were classified as 27 distinct viruses. These were distributed across different groups like bluetongue, epizootic haemorrhagic disease, Palyam, Simbu, bovine ephemeral fever, Tibrogargan, and alphavirus.
• Interestingly, ten of these viruses were exclusive to the region, having not been isolated anywhere else in Australia.
• Moreover, four among these ten were found only in Darwin, indicating a potential localized outbreak or distribution of these viruses.

Fluctuations in Virus Activity

• Researchers noted considerable annual differences in virus activity. These variations can be attributed to numerous factors including changes in the livestock’s exposure to infected vectors, and fluctuations in the vector population itself, possibly due to varying weather conditions.
• The durations of detectable viraemia also displayed significant variance. Viraemia refers to the presence of viruses in the bloodstream; substantial fluctuations in its duration can impact the timing and effectiveness of virus detection and subsequent disease control measures.

This study, therefore, presents valuable insights into the variety and prevalence of arboviruses in livestock populations in Northern Australia, contributing to the broader understanding of disease distribution and management.