[Stratified sampling survey of major human parasitic diseases in Henan province].

Objective: To understand the prevalence of major human parasitic diseases and related factors in Henan province. Methods: This stratified sampling survey was carried out according to the requirement of national survey protocol of major human parasitic diseases, 2014-2015. The prevalence of soil-transmitted helminths infection, taeniasis and intestinal protozoiasis were surveyed in 104 sites selected from 35 counties (districts) and the prevalence of clonorchiasis was surveyed in 62 sites selected from 37 townships. In each survey spot, 250 persons were surveyed. A total of 26 866 persons and 15 893 persons were surveyed. Modified Kato-Katz thick smear was used to detect the eggs of intestinal helminthes. Tube fecal culture was used to identify the species of hookworm. The Enterobius eggs were detected in children aged 3 to 6 years by using adhesive tape. The cyst and trophozoite of intestinal protozoa were examined with physiological saline direct smear method and iodine stain method. Results: The overall infestation rate of intestinal parasites was2.02% in Henan, and the worm infection rate was higher than protozoa infection rate. Fourteen kinds of intestinal parasites were found, including nematode (5 species), trematode (2 species), and protozoan (7 species). The infection rate of Enterobius vermicularis was highest, and Qinba Mountain ecological area had the highest infestation rate of intestinal parasites in 4 ecological areas of Henan. There was no significant difference in intestinal parasite infection rate between males and females (χ(2)=3.630, P=0.057), and the differences in intestinal parasite infection rate among different age groups had significance (χ(2)=124.783, P=0.000 1). The infection rate reached the peak in age group ≤9 years and the major parasite was Enterobius vermicularis. Furthermore the overall human infection rate of parasite showed a downward trend with the increase of educational level of the people (χ(2)=70.969, P=0.000 1), the differences had significance (χ(2)=120.118, P=0.000 1). For different populations, the infection rate of intestinal parasites was highest among preschool children. The infection of intestinal helminth was mainly mild, only 2 severe cases were detected. The infection rate of Clonorchis sinensis in urban residents was only 0.006%. Logistic regression analysis showed that being preschool children (χ(2)=15.765, P=0.000 1) and drinking well water (χ(2)=45.589, P=0.000 1) were the risk factors for intestinal parasite infection, and annual income per capita of farmers was the protective factor against intestinal parasite infection. The infection rates of protozoa and intestinal parasites decreased sharply compared with the results of previous two surveys, and the rate of intestinal helminth infection also dropped sharply compared with the second survey. The numbers of protozoa, helminth and intestinal parasites detected in this survey were all less than the numbers found in the previous two surveys. Conclusions: Compared the results of three surveys in Henan, the infection rate of protozoa and intestinal parasites showed a downward trend. The prevention and treatment of Enterobius vermicularis infection in children should be the key point of parasitic disease control in the future.

Targeted chemotherapy for parasite infestations in rural black preschool children.

OBJECTIVE: To investigate whether targeted chemotherapy can reduce parasite prevalence rates in rural black preschool children. DESIGN: The study consisted of a before/after trial. Stool and urine samples were analysed on four occasions over a 21-week period. SETTING: Crèches in two rural areas of southern KwaZulu/Natal (coastal and inland). PATIENTS: Two hundred children of 4-6 years of age attending 19 crèches in the area. INTERVENTION: Targeted chemotherapy using albendazole for nematode infestations, praziquantel for trematode and cestode infestations and metronidazole for protozoal infections was administered twice at an interval of 14 weeks. MAIN OUTCOME MEASURE: Prevalence rates. RESULTS: The prevalence of Ascaris lumbricoides, Trichuris trichiura and Necator americanus infestation decreased significantly after treatment. Reinfestation rates 12 weeks after treatment were 16% for A. lumbricoides, 33% for T. trichiura, 24% for Giardia lamblia and 3% for N. americanus. No reinfestation was noted for Schistosoma haematobium, Hymenolepsis or Taenia species. CONCLUSION: The study suggests that parasite prevalence rates in children can be reduced by the administration of appropriate chemotherapy at regular intervals. However, the provision of clean water and adequate sewerage facilities remains a high priority for black communities living in rural areas of South Africa.