Abstract
Simple SummaryPrevious 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.
Highlights
There are a range of recognised pathological conditions that affect the canine fundus, including diseases that have been described in specific breeds [1,2,3]
A previous study by Hughes et al (1987) [4] identified that multifocal retinitis was present in working sheep dogs; the authors observed that retinitis was more prevalent in the study population of working sheep dogs (39% of 1448 dogs) than in the population of urban dogs examined by the authors for comparative measures (6% of 125 dogs)
The aims of this study were to investigate whether evidence for chorioretinopathy was still present in working sheep dogs, to determine its prevalence, and to associate the prevalence of chorioretinopathy with age, gender, breed, and Toxocara canis infection status
Summary
There are a range of recognised pathological conditions that affect the canine fundus, including diseases that have been described in specific breeds [1,2,3]. Pet dogs in a rural environment had a retinitis prevalence of 43% (30/70 dogs), portraying a similar risk as their working counterparts. These authors identified that ocular larval migrans, due to migrating ascarid larvae, was one cause of the retinitis and that. The aims of this study were to investigate whether evidence for chorioretinopathy was still present in working sheep dogs, to determine its prevalence, and to associate the prevalence of chorioretinopathy with age, gender, breed, and Toxocara canis infection status. The terms chorioretinitis (inflammation affecting the choroid and adjacent retina) and chorioretinopathy (any lesion of the choroid and retina including non-inflammatory causes) are used in preference to retinitis and retinopathy as the close proximity and functional intimacy of the retina and choroid mean that inflammation of one of these tissues will normally lead to inflammation of the other, resulting in chorioretinitis or retinochoroiditis [5]
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