Estimation of hookworm intensity by anthelmintic expulsion in primary schoolchildren in south India

Prevalence and distribution of soil-transmitted helminth infections in India

Background

Understanding the prevalence of soil-transmitted helminth infections is necessary to plan control strategies and focus on highly endemic regions for preventive chemotherapy and improved sanitation facilities. India is known to be endemic for soil-transmitted helminth infections.

Methods

To understand the prevalence, spatial distribution and identify high-risk zones, a systematic search of published literature was carried out based on PRISMA guidelines from the year 2000 to 2015.

Results

A careful screening of the identified literature yielded 39 studies that reported the prevalence of soil-transmitted helminth infections from 19 different states of India. Ascaris lumbricoides was the most prevalent parasite. Higher than 50% prevalence was reported from six states. Nearly 90% studies reported the prevalence of more than one parasite species in the same sample population.

Conclusion

This is the first study to comprehensively review the literature associated with soil-transmitted helminth infections from India giving a clear idea of its prevalence, distribution and high endemic areas.

Hepatic and biliary ascariasis

Ascariasis mainly contributes to the global helminthic burden by infesting a large number of children in the tropical countries. Hepato-biliary ascariasis (HBA) is becoming a common entity now than in the past owing to the frequent usage of ultrasonograms and endoscopic diagnostic procedures in the clinical practice. There are a variety of manifestations in HBA and diagnosis depends on a high index of suspicion in endemic areas coupled with subsequent confirmation by sonographic or endoscopic demonstration of the worm. Most of them present with acute abdomen and jaundice. Oriental or recurrent pyogenic cholangiopathy is possibly the result of HBA, commonly encountered in South-East Asian countries. Conservative treatment with anthelminthic agents is used in the majority. Failure to respond to medical therapy usually indicates the need for endoscopic or surgical interventions. Overall, mortality is low and prognosis is good, but many epidemiological and immunological aspects of Ascaris infection are unclear, meaning our understanding the disease and infection still remains incomplete. Therefore, it is difficult to definitely put down a fixed modality of treatment for HBA. This underscores the need for further studies as ascariasis has the potential to adversely affect the national socio-economy by compromising the health of children and adults alike with its sheer number.

Intestinal helminth infections among school children in Visakhapatnam

A study was carried out between 1993-1994 to determine the prevalence and intensity of intestinal helminth infections among 217 primary school children in Relliveedhi, a slum area in Visakhapatnam. The children were between 7 to 13 years of age and belonged to lower socio-economic status. Stool samples collected were processed by modified formalin-ethyl acetate sedimentation technique to determine ova counts (EPG). One hundred and seventy seven children were infected with one or more of the intestinal parasites viz. Ascaris lumbricoides, Trichuris trichiura and hookworm. The overall prevalence of infection was eighty two per cent. Ascaris lumbricoides was the most common infection with a prevalence of 75% followed by T. trichiura (66%) and hookworm (9%). All infected children received a single dose of albendazole (400 mg/child). Single stool samples were examined over a period of nine months to study reinfection dynamics.

Efficacy of albendazole against Giardia and hookworm in a remote Aboriginal community in the north of Western Australia

The parasitological, clinical efficacy and tolerability of albendazole in the treatment for both giardiasis and hookworm infection in a remote Aboriginal population was investigated. Albendazole at a dose rate of 400 mg daily for 5 days was highly effective in reducing hookworm egg numbers and both Giardia antigen and cysts. The 36.6% prevalence of Giardia prior to treatment fell to 12% between days 6 and 9, 15% for days 10-17 and rose to 28% between days 18 and 30. Tolerability and clinical efficacy were excellent. The effect of albendazole on hookworm was longer lasting than that on Giardia, reducing percent infection from over 76-2% on days 6-9 and zero by day 18-30 despite conditions highly conducive to rapid re-infection. We conclude that albendazole is highly efficacious against both parasites when used as described but that long term community benefit may require additional education programmes to avoid re-infection with Giardia although treatment strategies would seem appropriate for hookworm.

Failure of pyrantel in treatment of human hookworm infections (Ancylostoma duodenale) in the Kimberley region of north west Australia

A survey of 108 individuals from a coastal Aboriginal community in north Western Australia revealed that two species of gastrointestinal protozoan parasites (Giardia duodenalis--39.8%, Entamoeba coli--40.7%) and five gastrointestinal helminths (Hymenolepis nana--54.6%, Hookworm [Ancylostoma duodenale]--30.6%, Enterobius vermicularis--6.5%, Trichuris trichiura--2.8%, Strongyloides stercoralis 1.9%) were present. A total of 29 individuals infected with hookworm were offered treatment with either pyrantel pamoate at a single dose rate of 10 mg/kg body weight or albendazole (single 400 mg dose). Seven days after treatment stool samples were examined. Pyrantel had no significant effect against hookworm. In contrast, albendazole cleared hookworm infections completely and reduced the prevalence of Giardia. The former result suggests that locally A. duodenale is resistant to pyrantel and despite its relatively low cost and wide availability, should not be considered a drug of choice at this dose rate in the treatment of hookworm infections (A. duodenale) in endemic regions.