Abstract:

Objective To analyze the prevalence of soil-transmitted nematode infections in populations living in rural areas of Xiangcheng District in Zhangzhou City of Fujian Province, the national surveillance site, during 2011-2015. Methods Five surveillance sites were set in Xiangcheng District during 2011-2015: Dazhai village, Qiukeng Village, Shanmei Village, Gantang Village, and Pulin Village in Eastern, Western, Southern, Northern and Central regions of Xiangcheng District, respectively. The modified Kato-Katoz’s thick smear method was used to detect the eggs of soil transmitted nematodes and the cellophane tape method was used to detect the eggs of Enterobius vermicularis in children aged 3-12 years. Seventy families were randomly selected to obtain soil samples in vegetable garden, orchard and other plantations, from which Ancylostoma sp. larvae were isolated and incubated to identify their species. Results A total of 5 352 persons were examined, of whom 572 (10.7%) were positive for nematode infections. The infection rates during 2011-2015 were 14.3% (146/1 022), 14.7% (155/1 052), 4.0% (42/1 053), 7.3% (78/1 067) and 13.0% (151/1 158), respectively. The nematode infection detected was predominated by Ancylostoma sp. infection(5.9%, 318/5 352), which was highest in 2011 (10.8%, 110/1 022) in the years (6.2%, 65/1 052; 1.4%, 15/1 053; 3.2%, 34/1 067; and 8.1%, 94/1 158 from 2012-2015, respectively), and all the infected persons showed light infection. Ascaris lumbricoides infection was only detected in 2 persons in 2012, and both had light infection. Trichuris trichiura infection was detected in 1, 1, and 2 persons in 2012, 2014 and 2015, respectively, all showing light infection. E. vermicularis infection was examined in 668 children, and 248 showed positive infection (37.1%), and the infection rate was lowest in 2014 (27.7%, 43/155) and highest in 2012 (56.5%, 87/154). The prevalence of soil-transmitted nematode infection in males (11.6%, 300/2 595) was higher than in females (9.87%, 272/2 757) (P < 0.05). The prevalence showed a trend of increase with aging except for the < 15 age group, lowest in 15-24 years (1.9%, 5/266) and highest in > 65 years (11.0%, 98/889) (P < 0.05). Most of those with infections were illiterate or semi-illiterate (23.9%, 245/1 025), or had a primary school educational level (11.9%, 238/1 995). The infection rate decreased with higher educational level (χ² = 308.16, P < 0.05). Ancylostoma sp. larvae were found in 19 of 75 soil samples, and all were identified to be Necator americanus. The number of positive soil samples was highest in Dazhai village (10 samples). Conclusion There was a trend of decrease for the soil-transmitted nematode infections during 2011-2015, but the pinworm infection in children remained high.

Key words: Nematode infection, Soil-transmitted nematode, Surveillance, Report