Cutaneous myiasis by Calliphoridae dipterans in dogs from Chad

Cutaneous myiasis caused by various Calliphoridae dipteran species is prevalent worldwide and is of particular veterinary and public health concern. Recently, in a scientific exploration of the Guinea Worm Eradication Program to Chad, Africa, we observed that dogs with mutilated ears, based on local awareness, were caused by cutaneous myiasis. In this study, we analyzed epidemiological, morphological, and molecular data on cutaneous myiasis in dogs from Chad. From September to October 2022, dogs (n = 1,562) from 56 villages situated along the Chari River were physically inspected for cutaneous myiasis. All larvae were collected and identified morphologically and by molecular analysis of the partial cytochrome oxidase c subunit I (COI) mitochondrial gene. The prevalence of myiasis infestation along with 95 % confidence intervals (95 % CI) was determined using the modified Wilson method. Myiasis was detected in dogs from 21 villages (37.5 %; 95 % CI 26 – 50 %), predominating in the southernmost region. Of 1,562 dogs, 66 (4.22 %; 95 % CI 3.34 – 5.34 %) were infested by calliphorid larvae, with a mean infestation of 2.28 larvae per animal (range = 1 to 24). Specimens were morphologically identified as Cordylobia anthropophaga (n = 94), Chrysomya bezziana (n = 54), and Chrysomya sp. (n = 3), which were detected in 57, eight and one dog, respectively. No co-infestations were observed. The molecular analyses confirmed the morphological identification and revealed the presence of 17 haplotypes for C. anthropophaga, 2 for C. bezziana, and one for Chrysomya sp. Our study emphasizes the veterinary importance of myiasis in dogs in Africa and proposes measures to assure their health and well-being.