Analysis of soil-transmitted helminth infection in populations in national surveillance sites of Jiangxi Province during 2016-2019

doi:10.12140/j.issn.1000-7423.2020.05.002

Abstract

Abstract:

Objective To understand the epidemic status of soil-transmitted helminth (STH) infection in the national surveillance sites in Jiangxi Province during 2016-2019, in order to provide scientific basis for formulating control strategy and evaluating the control effect. Methods National surveillance sites were set up in 11 counties (cities) in Jiangxi Province during 2016-2019, and surveillance was carried out according to the national clonorchiasis and soil-borne nematode surveillance program (provisional version). According to geographical location, each county at surveillance was divided into 5 areas, i.e. east, west, south, north and center areas. From a township of each area, an administrative village was selected as the surveillance site for 4 scheduled years, and no less than 200 permanent residents at age of 3 years or above were cluster sampled from each administrative village, while no less than 1 000 residents totaled from each surveillance site. Fecal samples were collected from the enrolled residents and were examined for STH eggs(two slide-reading/one sample) using the modified Kato-katz thick smear method to estimate infection rate and intensity. The samples of hookworm egg positive were further examined by test-tube filter paper incubation for larva to identify the species. The infection rate between groups was compared by the Chi-square test. Five households were randomly selected in each administrative village to collect soil sample in field or vegetable garden. From each household, 350 g soil was used for hookworm larva detection, and 50 g for Ascaris egg detection. The hookworm larvae in soil were identified by microscopy using 5% saline; the hookworm larvae in soil were detected using the saturated sodium nitrate floatation method. Results The production mode of the 11 surveillance sites were mainly the agricultural mode, and the types of drinking water were mainly tap water and well water. From 2016 to 2019, the coverage rates of sanitary toilets were 78.4% (30 443/38 817), 80.7% (32 856/40 723), 85.6% (35 301/41 258), and 91.0% (37 964/41 730), respectively. The differences between years were statistically significant (P < 0.01). The STH infection rate in the population in the 4 years was 1.6% (175/11 126), 1.4% (160/11 203), 0.8% (91/11 183) and 1.3% (151/11 197), respectively. The infection rate showed an overall downward trend, with a decrease of 14.1% in 2019 compared with 2016; the differences between the years were statistically significant (P < 0.01). The infection rate of STH in Nanfeng county was 4.7% (48/1 016), 3.8% (39/1 034), 2.6% (27/1 028) and 7.4% (75/1 010) in the 4 years, respectively, which were significantly higher than other counties (P < 0.01). The hookworm infection rate fluctuated from 1.0% (116/11 126) in 2016 to 0.6% (70/11 183) in 2018, and then increased to 1.0% (112/11 197) in 2019. The difference was statistically significant between the years (P < 0.01). The infection rates of STH and hookworm in females was higher than that in males, except in 2016. Among the hookworm infected, Necator americanus accounted for 92.2% (71/77), 91.0% (61/67), 97.8% (44/45) and 91.8% (89/97) identified by hookworm larva culture in the 4 years, respectively, while the rest of cases were mixed infection, and single Ancylostoma duodenale infection. The infection rate of Ascaris lumbricoides decreased from 0.5% (53/11 126) in 2016 to 0.3% (29/11 197) in 2019, showing an overall trend of decrease; the differences between years were statistically significant (P < 0.01). The infection rate of Trichuris trichiura was 0.1% (6/11 126), 0.1% (14/11 203), 0.1% (9/11 183) and 0.1% (10/11 197), respectively. The positive rate of Ascaris eggs in soil samples in the 4 years was 9.1% (25/275), 1.8% (5/275), 1.8% (5/275) and 1.5% (4/275), respectively; the differences were statistically significant(P < 0.01). The positive rates of Ascaris eggs and hookworm larvae in soil samples both showed a decreasing trend. Conclusion The STH infection rate and the proportions of moderate and severe infection showed a trend of decrease year by year, displaying a low prevalent status. Hookworm remains the key target parasite, and Nanfeng county the key area for STH control in the future.

Key words: Soil-transmitted helminth, Infection, Surveillance, Hookworm, Ascaris lumbricoides, Trichuris trichiura, Jiangxi Province

CLC Number:

R532.1

CHEN Zhe, JIANG Wei-sheng, LI Dong, GE Jun, DAI Kun-jiao, ZENG Xiao-jun, ZHU Ting-jun. Analysis of soil-transmitted helminth infection in populations in national surveillance sites of Jiangxi Province during 2016-2019[J]. CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES, 2020, 38(5): 534-541.

Figures/Tables 4

Table 1

Prevalence of soil-transmitted helminth infection in different counties in national surveillance sites in Jiangxi Province, 2016-2019

年份 Year	县(市) County(City)	检查人数 No. examined	土源性线虫 Soil-transmitted helminth		钩虫 Hook worm		蛔虫 A. lumbricoides		鞭虫 T. trichiura
年份 Year	县(市) County(City)	检查人数 No. examined	感染人数 No. infected	感染率/% Positive rate/%	感染人数 No. infected	感染率/% Positive rate/%	感染人数 No. infected	感染率/% Positive rate/%	感染人数 No. infected	感染率/% Positive rate/%
2016	分宜Fenyi	987	29	2.9	27	2.7	2	0.2	0	0
	浮梁Fuliang	1 002	8	0.8	0	0	6	0.6	2	0.2
	贵溪Guixi	999	20	2.0	18	1.8	2	0.2	0	0
	吉安Ji’an	1 032	5	0.5	4	0.4	1	0.1	0	0
	庐山Lushan	1 026	5	0.5	0	0	3	0.3	2	0.2
	南昌Nanchang	1 000	1	0.1	0	0	1	0.1	0	0
	南丰Nanfeng	1 016	48	4.7	48	4.7	0	0	0	0
	上高Shanggao	1 000	0	0	0	0	0	0	0	0
	遂川Suichuan	1 021	35	3.4	18	1.8	16	1.6	1	0.1
	婺源Wuyuan	997	5	0.5	0	0	5	0.5	0	0
	于都Yudu	1 046	19	1.8	1	0.1	17	1.6	1	0.1
	小计Subtotal	11 126	175	1.6	116	1.0	53	0.5	6	0.1
2017	分宜Fenyi	999	18	1.8	17	1.7	1	0.1	0	0
	浮梁Fuliang	1 004	6	0.6	1	0.1	5	0.5	0	0
	贵溪Guixi	1 000	22	2.2	13	1.3	9	0.9	0	0
	吉安Ji’an	1 123	4	0.4	4	0.4	0	0	0	0
	庐山Lushan	993	0	0	0	0	0	0	0	0
	南昌Nanchang	1 021	30	2.9	19	1.9	0	0	11	1.1
	南丰Nanfeng	1 034	39	3.8	38	3.7	0	0	1	0.1
	上高Shanggao	1 000	6	0.6	3	0.3	2	0.2	1	0.1
	遂川Suichuan	989	27	2.7	27	2.7	1	0.1	0	0
	婺源Wuyuan	1 002	3	0.3	0	0	3	0.3	0	0
	于都Yudu	1 038	5	0.5	0	0	4	0.4	1	0.1
	小计Subtotal	11 203	160	1.4	122	1.1	25	0.2	14	0.1
2018	分宜Fenyi	1 000	7	0.7	7	0.7	0	0	0	0
	浮梁Fuliang	1 000	8	0.8	0	0	7	0.7	1	0.1
	贵溪Guixi	1 000	23	2.3	21	2.1	2	0.2	0	0
	吉安Ji’an	1 101	0	0	0	0	0	0	0	0
	庐山Lushan	1 021	0	0	0	0	0	0	0	0
	南昌Nanchang	1 008	8	0.8	0	0	0	0	8	0.8
	南丰Nanfeng	1 028	27	2.6	27	2.6	0	0	0	0
	上高Shanggao	1 000	0	0	0	0	0	0	0	0
	遂川Suichuan	1 006	16	1.6	15	1.5	1	0.1	0	0
	婺源Wuyuan	1 002	0	0.0	0	0	0	0	0	0
	于都Yudu	1 017	2	0.2	0	0	2	0.2	0	0
	小计Subtotal	11 183	91	0.8	70	0.6	12	0.1	9	0.1
2019	分宜Fenyi	1 015	6	0.6	5	0.5	1	0.1	0	0
	浮梁Fuliang	1 027	2	0.2	0	0	2	0.2	0	0
	贵溪Guixi	1 000	20	2.0	13	1.3	7	0.7	0	0
	吉安Ji’an	1 068	3	0.3	3	0.3	0	0	0	0
	庐山Lushan	1 019	1	0.1	0	0	0	0	1	0.1
	南昌Nanchang	1 002	5	0.5	2	0.2	0	0	3	0.3
	南丰Nanfeng	1 010	75	7.4	75	7.4	0	0	0	0
	上高Shanggao	1 000	8	0.8	1	0.1	6	0.6	1	0.1
	遂川Suichuan	1 020	18	1.8	7	0.7	11	1.1	0	0
	婺源Wuyuan	1 000	1	0.1	1	0.1	0	0	0	0
	于都Yudu	1 036	12	1.2	5	0.5	2	0.2	5	0.5
	小计Subtotal	11 197	151	1.3	112	1.0	29	0.3	10	0.1

Table 1

Table 2

Table 3

Age distribution of infection rate of soil-transmitted helminth in national surveillance sites in Jiangxi Province, 2016-2019

年份Year	年龄组 Age group	检查人数No. examined	土源性线虫STH		钩虫Hook worm		蛔虫A. lumbricoides		鞭虫T. trichiura
年份Year	年龄组 Age group	检查人数No. examined	感染人数 No. infected	感染率/% Infection rate/%	感染人数 No. infected	感染率/% Infection rate/%	感染人数 No. infected	感染率/% Infection rate/%	感染人数 No. infected	感染率/% Infection rate/%
2016	3~9	1 964	13	0.7	5	0.3	8	0.4	0	0
	10~19	832	5	0.6	2	0.2	3	0.4	0	0
	20~29	696	10	1.4	5	0.7	5	0.7	0	0
	30~39	985	16	1.6	13	1.3	3	0.3	0	0
	40~49	1 782	18	1.0	12	0.7	5	0.3	1	0.1
	50~59	2 055	32	1.6	20	1.0	10	0.5	2	0.1
	60~69	1 726	54	3.1	38	2.2	14	0.8	2	0.1
	≥ 70	1 086	27	2.5	21	1.9	5	0.5	1	0.1
	小计Subtotal	11 126	175	1.6	116	1.0	53	0.5	6	0.1
2017	3~9	1 791	4	0.2	1	0.1	2	0.1	1	0.1
	10~19	850	9	1.1	7	0.8	1	0.1	1	0.1
	20~29	811	2	0.2	1	0.1	1	0.1	0	0
	30~39	1 043	17	1.6	14	1.3	1	0.1	2	0.2
	40~49	1 809	31	1.7	24	1.3	3	0.2	4	0.2
	50~59	2 055	24	1.2	19	0.9	5	0.2	0	0
	60~69	1 732	51	2.9	42	2.4	6	0.3	3	0.2
	≥ 70	1 112	22	2.0	14	1.3	6	0.5	3	0.3
	小计Subtotal	11 203	160	1.4	122	1.1	25	0.2	14	0.1
2018	3~9	1 430	7	0.5	3	0.2	4	0.3	0	0
	10~19	879	4	0.5	3	0.3	0	0	1	0.1
	20~29	804	3	0.4	1	0.1	1	0.1	1	0.1
	30~39	1 032	6	0.6	5	0.5	1	0.1	0	0.0
	40~49	1 753	12	0.7	10	0.6	0	0	2	0.1
	50~59	2 188	19	0.9	15	0.7	2	0.1	2	0.1
	60~69	1 778	19	1.1	17	1.0	1	0.1	1	0.1
	≥ 70	1 319	21	1.6	16	1.2	3	0.2	2	0.2
	小计Subtotal	11 183	91	0.8	70	0.6	12	0.1	9	0.1
2019	3~9	1 308	9	0.7	5	0.4	4	0.3	0	0
	10~19	1 003	9	0.9	3	0.3	6	0.6	0	0
	20~29	692	5	0.7	4	0.6	0	0	1	0.1
	30~39	1 074	15	1.4	11	1.0	4	0.4	0	0
	40~49	1 551	18	1.2	13	0.8	4	0.3	1	0.1
	50~59	2 168	33	1.5	25	1.2	5	0.2	3	0.1
	60~69	1 850	32	1.7	28	1.5	2	0.1	2	0.1
	≥ 70	1 551	30	1.9	23	1.5	4	0.3	3	0.2
	小计Subtotal	11 197	151	1.3	112	1.0	29	0.3	10	0.1

Table 3

Table 4

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