HumanChrysomya bezzianamyiasis: A systematic review

BackgroundMyiasis due to Old World screw-worm fly,Chrysomya bezziana, is an important obligate zoonotic disease in the OIE-list of diseases and is found throughout much of Africa, the Indian subcontinent, southeast and east Asia.C. bezzianamyiases cause not only morbidity and death to animals and humans, but also economic losses in the livestock industries. Because of the aggressive and destructive nature of this disease in hosts, we initiated this study to provide a comprehensive understanding of human myiasis caused byC. bezziana.MethodsWe conducted a systematic search of the databases in English (PubMed, Embase and African Index Medicus) and Chinese (CNKI, Wanfang, and Duxiu), and international government online reports to 6thFebruary, 2019, to identify studies concerningChrysomya bezziana. Another ten human cases in China and Papua New Guinea that our team had recorded were also included.ResultsWe retrieved 1,048 reports from which 202 studies were ultimately eligible for inclusion in the present descriptive analyses. Since the first human case due toC. bezzianawas reported in 1909, we have summarized 291 cases and found that these cases often occurred in poor hygiene, low socio-economic conditions, old age, and underlying diseases including infections, age-related diseases, and noninfectious chronic diseases. ButC. bezzianamyiasis appears largely neglected as a serious medical or veterinary condition, with human and animal cases only reported in 16 and 24 countries respectively, despite this fly species recorded as present in 44 countries worldwide.ConclusionOur findings indicate that cryptic myiasis cases due to the obligate parasite,C. bezziana,are under-recognized. Through this in-depth study to clarify the knowledge of humanC. bezzianamyiasis including its etiology, clinical features, diagnosis, treatment, epidemiology, prevention and control, we call for more vigilance and awareness of the disease from governments, health authorities, clinicians, veterinary workers, nursing homes, and also the general public.Author summaryChrysomya bezzianalarvae are characterized by feeding aggressively on the living tissues and body fluids of the host. The nightmare-like feelings of patients suffering from this myiasis, severe tissues and bones destruction, even death, and enormous economic loss in the livestock industries have been described in the previous reports. But our findings indicate thatC. bezzianamyiases still appear to be under-recognized as a serious medical or veterinary condition throughout the world. Both in China and the world at large, it is probable thatC. bezzianadistribution could be greater than currently reported. For the first time, we have therefore systematically investigated human myiasis caused byC. bezziana. Our study provides an opportunity for clinicians and health authorities to gain a better understanding of this disease from its etiology, pathology, clinical features, diagnosis, treatment, epidemiology, prevention and control. In addition, our findings will hopefully engage governments, health staff, veterinary workers, the elderly homes, and also the general public in efforts to recognize, prevent and control such infestations.