Evidence For The Continued Occurrence Of Chorioretinopathy In Working Sheep Dogs In New Zealand In 2010

Simple Summary Previous research in New Zealand on working sheep dogs has found that 39% suffered from retinal eye disease. One of the causes of this eye disease is parasite migration to the eye. Since that research was published in 1987, farmers have been educated to regularly treat farm dogs with anti-parasitic tablets. However, there has been no follow-up studies to see if eye disease is still a problem in working farm dogs. Our study investigated whether eye disease is still present in working sheep dogs in South-West, Waikato, New Zealand. Our study of 184 working sheep dogs and 51 owners was undertaken in 2010, with owners sampled from New Zealand's South-West Waikato and Tux North Island Dog Trial Championship. Eye examinations were performed on all of the dogs that participated. This study identified that 24% (44/184) of the dogs in the study showed evidence of retinal eye disease. Male working sheep dogs are more susceptible to develop retinal eye disease than females for unidentified reasons. This study concluded that retinal eye disease is still present in working sheep dogs in New Zealand. A study in conducted 1987 by Hughes et al., found that 39% of working sheep dogs had multifocal retinitis. One of the identified causes was ocular larval migrans, which were a result of migrating ascarid larvae. Since that paper was published, anthelmintic use in farm dogs has been highly recommended. There has been no follow-up study to determine if fundic lesions are still present. The current study aimed to investigate the prevalence of chorioretinopathy in working sheep dogs in the South-West, Waikato, New Zealand. This was a cross-sectional study of 184 working sheep dogs and 51 owners, undertaken in 2010 with owners sampled from New Zealand's South-West Waikato and Tux North Island Dog Trial Championship. Two-way tables were used to explore the relationship between variables. Significance of association was assessed using a Chi-squared or Fisher exact test as appropriate, with a p-value of <0.05 considered significant. Overall prevalence of chorioretinopathy in the working sheep dogs was 44/184 (24%). A significantly higher prevalence of chorioretinopathy was shown in dogs with increasing age, from 2 years to >8 years (p = 0.0007) and in males (p < 0.0001). This study concluded that lesions of chorioretinopathy are still present in working sheep dogs in New Zealand.