Epidemiology of taenia solium taeniasis/cysticercosis in India and Nepal

Abstract

The fact that cysticercosis is a major health hazard in India and Nepal is evident from the large number of patients with neurocysticercosis (NCC) managed in hospitals in the two countries in recent years. Unfortunately, population-based epidemiological data on Taenia solium taeniasis and cysticercosis are lacking from both countries. Hospital-based data and small population-based studies form the basis of this report. India: cysticercosis is prevalent in virtually all states of India, the only possible exceptions being Kerala, and Jammu and Kashmir. It is generally believed that the disease is more prevalent in north than south India. NCC accounts for anywhere between 8.7-50% of patients presenting with recent onset of seizure. The peculiarity of the disease in India is the high incidence of patients with the solitary form of the disease, namely solitary cysticercus granuloma (SCG). About 60-70% of all Indian patients with NCC have a SCG. The reasons for the high incidence of SCG vis-à-vis the multilesional form of the NCC (MNCC) are unclear, but may be linked to the low parasite load in the community. The prevalence of taeniasis has been reported to be between 0.5-2%. However, a recent study in a pig-rearing community from the northern state of Uttar Pradesh reported that 17 of 72 (38%) members of that community had evidence of taeniasis. The prevalence of taeniasis is probably higher in northern than southern India. The prevalence of porcine cysticercosis has been studied in pig carcasses in slaughterhouses of north and east India and ranges from 7-12% although a recent study from the pig-rearing community in Uttar Pradesh placed the figure at 26%. Nepal: even hospital-based data on cysticercosis is lacking from Nepal because of the lack of access to CT scanners for the vast majority of patients. However, several patients from Nepal seek treatment in Indian hospitals and there have been reports of NCC in several Nepalese patients from Indian and other foreign hospitals. Recently, a study of taeniasis in certain ethnic groups of Nepal revealed a prevalence of 10-50%. Porcine cysticercosis rates were estimated to be 14 and 32% by examination of carcasses and lingual palpation of live pigs, respectively. It is evident from the data presented that cysticercosis is a major public health problem in both countries. Epidemiological data to estimate the magnitude of the problem has to be gathered. These data will help in getting the disease on the public health agenda of both countries. Steps towards control and possible eradication of the disease are needed, as the disease causes not only chronic morbidity, but also contributes to economic losses in an already impoverished population.