Occurrence of Oestrus ovis myiasis in Sheep from a Temperate Region

Oestrus ovis is a parasitic fly larva that causes the most important internal myiasis in sheep, which
produces variable damage to cranial structures, generating clinical manifestations that can be serious
in some animals. The objective was to determine the epidemiological situation of infection by O. ovis
in sheep in southern Chile, considered a temperate region with a cold season. Heads of 87 sheep
were examined by necropsy. The larvae were collected and identified by microscopy. The prevalence
in these sheep was 60.9%. Sheep between 1 to 3 years old showed the highest prevalence with
85.7% (18/21) of infected animals. The difference between the infection of males and females was not
significant. The large number of L3 in early summer confirms the development of infection in sheep
during the cold season and the greatest number of findings shows the risk of new infections in early
summer. In conclusion, this disease should be considered more seriously, deserving more attention in
its vigilance as a significant problem for livestock production.