Prevalence survey for zoonotic trematodes in nghia phu and nghia lac communes, nam dinh province, vietnam, 2005

Abstract

In April and May 2005, we conducted a survey in two communes in Nam Dinh Province, southeast of Hanoi, Vietnam. A total of 615 people including 563 men (91.5%) and 52 women (8.5%) were selected for stool examination. Based on the results of the fecal exams, using the Kato-Katz technique, a total of 554 (90.1%) people were positive for helminth eggs, including 5 types. Trichuris trrichiura eggs were found in 74.5% of stool samples, while 64.9% of the people were infected with small trematodes and 39.5% were infected with Ascaris lumbricoides. Hookworm and large trematode eggs were infrequent. Overall, 90.1% of these selected populations (mostly males) were infected with at least one type of helminth parasite. Mixed infections were common; most infected people harbored two types of parasite eggs (42.3%) but only 1.6% had four types of parasite eggs. Of the 563 males examined, 387 (68.7%) were found positive with small trematode eggs, which could not be speciated because of the morphological similarity of eggs of liver flukes such as Clonorchis sinensis and the minute intestinal flukes (Heterophyidae). Of 52 females examined, only 12 were positive (23.1%). The infection rate of trematodes, was highest among males and females in the older age group; the lowest was in the 40 and under age group. In the majority of the patients with small trematode eggs, the infection intensity was low, based upon eggs per gram of feces: about 86.2% had a low intensity of less than <1,000 epg feces and about 13.8% had a moderate infection intensity of less than <1,000-9,999 epg. None had a high intensity rate (>10,000 epg). Ascaris lumbricoides infections showed. There were no differences among age and gender groups with regard to A. lumbricoides infections. No age differences were discerned with these data on T.trichiura infections, but a larger sample is needed in order to be conclusive.