Neurocysticercosis in free roaming pigs--a slaughterhouse survey

My experience on taeniasis and neurocysticercosis

Taeniasis and neurocysticercosis (NCC) are major public health problems in developing countries. NCC is the leading cause of community-acquired active epilepsy. NCC may present as a medical emergency, especially when there is cysticercotic encephalitis or raised intracranial hypertension. Systematic community-based studies on taeniasis and NCC are lacking. We studied taeniasis and NCC-related active epilepsy disease burden in the pig farming community of Lucknow district, Uttar Pradesh, India. Based on the 30 cluster sampling approach as recommended by the World Health Organization, we estimated the prevalence of taeniasis, NCC-related active epilepsy, and silent NCC in the community. We also estimated the prevalence of swine cysticercosis. Taeniasis was detected in 18.6% of populations. Expulsions of tapeworm segments in stool, consumption of undercooked pork, age above 15 years, and handwash with clay or plain water after defecation were associated with taeniasis. On molecular analyses of positive stool samples, T. solium was identified in 40% and Taenia asiatica in 60% of cases. Active epilepsy was identified in 5.8% of subjects; 48% of them had NCC. On neuroimaging, NCC was detected in 15% of asymptomatic individuals. We observed that host genetic factors such as toll-like receptor-4, matrix metalloproteinase-9, intercellular adhesion molecule-1, and glutathione-S transferase gene polymorphisms were associated with seizure in NCC. When peripheral blood mononuclear cells (PBMCs) from NCC subjects were exposed to cysticerci fluid antigens in-vitro, PBMCs from symptomatic and asymptomatic subjects showed significantly higher Th 1 and Th 2 cytokines response respectively, symptomatic patients had significant Th-1 cytokines response, while asymptomatic individuals showed Th-2 response. Porcine cysticercosis was detected in 26% of swine; 38% of them had cysticerci in the brain. Swine with brain involvement showed clinical signs such as excessive salivation, excessive blinking and tearing, and subconjunctival nodule. On molecular analysis, 15% of cysticerci in swine were identified as T. asiatica. Infected swine when treated with albendazole plus/minus steroid, the response rate of cysticerci (either dead or resolved lesion) was 100% in albendazole-treated group and 71% in albendazole plus steroid-treated group. The above studies suggest that taeniasis and NCC are alarmingly high in the pig farming community of North India. Taeniasis in human and cysticercosis in swine due to T. asiatica call for further studies on this parasite.

Sarcocystis and sarcocystosis in India: status and emerging perspectives

Sarcocystis spp. are a group of tissue cyst-forming coccidia which infect a vast range of animals as well as human beings. Found frequently in animal carcasses at slaughter, undermining their value, they have also been found associated with clinical disease. Dogs and cats are involved in the transmission. Studies in India point to a vast reservoir of infection with high prevalence rates in various livestock species. However, there is a glaring paucity of reports on the horse and Sarcocystis of the camel has remained totally unexplored so far. At least two different Sarcocystis spp. can parasitize each livestock host species. Experimental transmission studies have provided additional parameters for distinguishing the species. The clinical symptoms are generally non-specific and diagnosis in the living animal, by the presently available means, is almost impossible. Immunodiagnosis till now is beset with problem of cross-reactivity. Treatment with anti-coccidials presently tried do not seem satisfactory. Of the two zoonotic species with cattle-man and pig-man cycles, only the latter seems of some significance in India due to backyard pig-rearing and slaughter practices. It is a paradox that despite high prevalence of S. suihominis in pigs, reports of human cases are limited. This and some of the existing grey areas of information in the Indian context, have been highlighted as also possible directions for future research.

Zoonotic helminth infections with particular emphasis on fasciolosis and other trematodiases

Zoonotic infections are among the most common on earth and are responsible for >60 per cent of all human infectious diseases. Some of the most important and well-known human zoonoses are caused by worm or helminth parasites, including species of nematodes (trichinellosis), cestodes (cysticercosis, echinococcosis) and trematodes (schistosomiasis). However, along with social, epidemiological and environmental changes, together with improvements in our ability to diagnose helminth infections, several neglected parasite species are now fast-becoming recognized as important zoonotic diseases of humans, e.g. anasakiasis, several fish-borne trematodiasis and fasciolosis. In the present review, we discuss the current disease status of these primary helminth zoonotic infections with particular emphasis on their diagnosis and control. Advances in molecular biology, proteomics and the release of helminth genome-sequencing project data are revolutionizing parasitology research. The use of these powerful experimental approaches, and their potential benefits to helminth biology are also discussed in relation to the future control of helminth infections of animals and humans.