The prevalence of canine dirofilariasis in China: a systematic review and meta-analysis

Dirofilariasis, the disease caused by Dirofilaria spp., and in particular by Dirofilaria immitis and Dirofilaria repens in canines, occurs frequently in canids and felids, and occasionally in humans, in temperate, sub-tropical and tropical regions globally. Although highly effective, safe and convenient preventive medicines have been available for the treatment of dirofilariasis for the past three decades, the disease remains a major veterinary and public health concern in endemic areas. The insect vectors, host-parasite relationships and interactions of Dirofilaria spp. have received little attention in China, and there is very little information in English regarding the prevalence of dirofilariasis in animals and humans in the country. The aim of this systematic review and meta-analysis is to evaluate the status of canine dirofilariasis in China based on the available literature in English and in Chinese.

We systematically searched five databases for epidemiologic studies on the prevalence of canine dirofilariasis in China and finally selected 42 studies eligible for inclusion in the systematic review and meta-analysis. The meta-analysis was performed using the random effects model in the meta package in R v4.2.1.

The random effects model gave a pooled and weighted prevalence of Dirofilaria infection among dogs in China in the past 100 years of 13.8% (2896/51,313, 95% confidence interval 8.2-20.4%) with a high level of heterogeneity (I² =  99.5%).

Our analyses indicated that the prevalence of canine dirofilariasis in China has gradually declined, but that the range of Dirofilaria spp. has expanded. Older and outdoor dogs presented a higher rate of positive infection. The findings indicated that more attention should be paid to host factors for the effective control and management of this disease.