Association of vectors and environmental conditions during the emergence of Peruvian horse sickness orbivirus and Yunnan orbivirus in northern Peru.

This study looks at the emergence of two new orbiviruses, namely Peruvian horse sickness virus (PHSV) and Yunnan virus (YUOV), in Northern Peru. These viruses, which cause neurological diseases in livestock and domestic animals, were discovered in 1997 and found in different mosquito species, leading researchers to investigate the ecology of these mosquitoes during the outbreak period.

Study Background

• In 1983, cases of diseased donkeys and horses resembling symptoms produced by alphaviruses were identified in two departments in northern Peru. However, serological testing discarded the presence of those viruses and efforts to isolate any agent were unsuccessful.
• In 1997, the situation changed with the discovery of two previously unknown orbiviruses in the same region. These were identified as causative agents for neurological diseases in livestock and domestic animals.
• Simultaneously, it was found that mosquitoes were infected with these newly discovered orbiviruses.

The Discovery of PHSV and YUOV

• The Peruvian horse sickness virus (PHSV) was isolated from mosquito species – Aedes serratus and Psorophora ferox, while the Yunnan virus (YUOV) was isolated from Aedes scapularis.
• Both viruses were found in the subtropical jungle (upper jungle) on the slope between the east side of the Andes and the Amazonian basin in the Department of San Martín. The viruses were later discovered in mosquitoes collected above the slope between the west side of the Andes and the coast in the Department of Piura, associated with the Piura River basin.
• In this region, PHSV was isolated from Anopheles albimanus and YUOV was isolated from Ae. scapularis.

Ecology of Vector Mosquitoes

• The study also discusses the ecology of these vector mosquitoes during the outbreaks where they were found. The examination of environmental conditions and mosquito vector behavior helps to better understand the circumstances leading to virus emergence.

Finally, while the study provides important initial insights into the incident of PHSV and YUOV and the possibility of mosquitoes serving as their vectors, unanswered questions remain. For instance, further implications of these findings on the general public, or other animal species and the contributing factors towards the outbreak are areas that necessitate further research.