Surveillance on soil-transmitted helminth infections in Yunnan Province from 2016 to 2022

doi:10.12140/j.issn.1000-7423.2023.06.008

Abstract

Abstract:

Objective To understand the prevalence and transmission of soil-transmitted helminth (STH) infection in Yunnan Province, providing scientific basis for formulating prevention and control strategies and measures. Methods The surveillance sites were selected in Yunnan Province according to the National Surveillance Program for Clonorchiasis and Soil-transmitted Nematodes (Pilot) from 2016 to 2022. From each district (city), at least one county (city, township) was selected as the surveillance site, which was further divided into 5 sectors (east, west, south, north and central) according to the geographic location. From each sector, one township (town) was selected randomly and an administrative village was selected from the township (town) to conduct the surveillance among permanent residents over 3 years old. No less than 200 residents were cluster sampled from each administrative village and no less than 1 000 residents from each surveillance site. Fecal samples (about 30 g) from the enrolled residents were collected and examined for STH eggs (hookworm, Ascaris lumbricoides, Truchuris trichiura and Enterobius vermicularis) by modified Kato-Katz thick smear method (two slide-reading for each sample). The infection rate and intensity of STH were calculated. The hookworm egg positive samples were further identified for species by tube-filter paper culture method. Children aged 3-9 were additionally examined for E. vermicularis eggs with transparent tape and anal swab method. Chi-square test was used to compare the infection rates. Results A total of 108 221 residents were enrolled in the surveillance from 71 surveillance sites in Yunnan Province and the total STH infection rate was 6.91% (7 475/108 221) from 2016 to 2022. The infection rates of hookworm, A. lumbricoides, T. trichiura and E. vermicularis were 3.75% (4 056/108 221), 1.68% (1 817/108 221), 2.23% (2 408/108 221) and 0.11% (121/108 221) respectively. A total of 1 288 cases of hookworm infection were identified by tube-filter paper culture method. 93.09% (1 199/1 288) of them were infected with Necator americanus, 6.13% (79/1 288) were infected with Ancylostoma duodenale and 0.78% (10/1 288) were co-infected. From 2016 to 2022, the annual infection rates of STH in Yunnan Province were 12.03% (1 606/13 350), 8.67% (1 317/15 195), 7.10% (1 095/15 425), 5.37% (897/16 693), 5.83% (969/16 617), 5.77% (922/15 967) and 4.47% (669/14 974) respectively. The differences between the infection rates among different years were statistically significant (χ² = 880.360, P < 0.01). Among the 16 prefectures (cities) surveyed, the highest STH infection rate was found in Xishuangbanna (26.21%, 1 312/5 006) and the lowest was found in Lijiang City (0.15%, 6/4 041). The differences between the infection rates among different prefectures (cities) were statistically significant (χ² = 8 081.151, P < 0.01). The STH infection rates in male and female were 6.35% (3 199/50 409) and 7.40% (4 276/57 812) respectively, with a significant difference (χ² = 46.198, P < 0.01). Among the different age-groups, nationalities, occupations and educational levels, the highest infection rates were found in the group of 10 to 19 year-old (8.56%, 1 249/14 592), Bulang ethnic group (30.20%, 778/2 576), students (7.96%, 1 638/20 588) and illiteracy or semi-illiteracy group (10.06%, 1 078/10 719), with the significant differences (χ² = 139.432, 8 546.389, 324.218, 833.291; all P < 0.01). Conclusion From 2016 to 2022, the STH infection rate in Yunnan Province showed a decreasing trend, but remained at a comparatively high level in some areas. It is imperative to continuously strengthen comprehensive control of STH for the key population including the ethnic groups near the border areas, farmers and the elderly.

Key words: Soil-transmitted helminth, Infection rate, Surveillance, Yunnan Province

CLC Number:

R532.1

WU Fangwei, PENG Jia, ZI Jinrong, LI Benfu, YAN Xinliu, CAI Xuan, WANG Zhengqing, XU Qian, LI Jianxiong, YANG Yaming. Surveillance on soil-transmitted helminth infections in Yunnan Province from 2016 to 2022[J]. CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES, 2023, 41(6): 718-724.

Figures/Tables 3

Table 1

Table 2

Table 3

Population distribution of human soil-transmitted helminth infection in Yunnan Province from 2016 to 2022

特征 Feature	调查人数 No. investigated	总感染人数 Total no. infected	总感染率/% Total infection rate/%	钩虫 Hookworm		蛔虫 A. lumbricoides		鞭虫 T. trichiura		蛲虫 E. vermicularis
特征 Feature	调查人数 No. investigated	总感染人数 Total no. infected	总感染率/% Total 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/%	感染人数 No. infected	感染率/% Infection rate/%
性别 Gender
男 Male	50 409	3 199	6.35	1 697	3.37	773	1.53	1 043	2.07	57	0.11
女 Female	57 812	4 276	7.40	2 359	4.08	1 044	1.81	1 365	2.36	64	0.11
年龄组/岁 Age group/Year
3~9	13 477	787	5.84	191	1.42	350	2.60	395	2.93	60	0.45
10~19	14 592	1 249	8.56	260	1.78	382	2.62	859	5.89	36	0.25
20~29	8 364	456	5.45	223	2.67	144	1.72	149	1.78	2	0.02
30~39	14 252	890	6.24	506	3.55	203	1.42	257	1.80	8	0.06
40~49	18 250	1 213	6.65	786	4.31	257	1.41	271	1.48	1	0.01
50~59	18 788	1 349	7.18	997	5.31	221	1.18	199	1.06	9	0.05
60~69	12 414	941	7.58	672	5.41	168	1.35	155	1.25	3	0.02
70~79	6 349	475	7.48	337	5.31	74	1.17	94	1.48	1	0.02
≥ 80	1 735	115	6.63	84	4.84	18	1.04	29	1.67	1	0.06
民族 Nationality
阿昌族 Achang	252	7	2.78	4	1.59	1	0.40	2	0.79	0	0.00
白族 Bai	8 888	39	0.44	15	0.17	9	0.10	17	0.19	0	0.00
德昂族 De’ang	413	48	11.62	0	0.00	2	0.48	47	11.38	1	0.24
布朗族 Bulang	2 576	778	30.20	365	14.17	265	10.29	266	10.33	3	0.12
藏族 Zang	1 819	75	4.12	6	0.33	51	2.80	29	1.59	0	0.00
傣族 Dai	6 008	771	12.83	728	12.12	28	0.47	16	0.27	5	0.08
独龙族 Dulong	1 514	421	27.81	73	4.82	221	14.6	256	16.91	23	1.52
哈尼族 Hani	5 332	1 116	20.93	406	7.61	208	3.90	675	12.66	31	0.58
汉族 Han	50 946	1 768	3.47	1 053	2.07	426	0.84	363	0.71	13	0.03
回族 Hui	847	52	6.14	9	1.06	32	3.78	15	1.77	0	0.00
景颇族 Jingpo	209	1	0.48	1	0.48	0	0.00	0	0.00	0	0.00
拉祜族 Lahu	2 745	683	24.88	655	23.86	15	0.55	49	1.79	4	0.15
傈僳族 Lisu	4 938	387	7.84	101	2.05	206	4.17	215	4.35	5	0.10
苗族 Miao	1 213	113	9.32	31	2.56	52	4.29	49	4.04	1	0.08
纳西族 Naxi	2 398	31	1.29	0	0.00	29	1.21	1	0.04	1	0.04
怒族 Nu	1 293	139	10.75	24	1.86	68	5.26	72	5.57	2	0.15
佤族 Wa	2 459	301	12.24	147	5.98	71	2.89	126	5.12	0	0.00
瑶族 Yao	1 119	134	11.97	50	4.47	39	3.49	54	4.83	8	0.71
彝族 Yi	9 759	485	4.97	350	3.59	37	0.38	134	1.37	6	0.06
壮族 Zhuang	3 142	111	3.53	28	0.89	54	1.72	20	0.64	17	0.54
其他 Others	351	15	4.27	10	2.85	3	0.85	2	0.57	1	0.28
职业 Occupation
餐饮食品业 Food worker	124	0	0.00	0	0.00	0	0.00	0	0.00	0	0.00
干部职员 Cadre	287	2	0.70	0	0.00	0	0.00	2	0.70	0	0.00
工人 Worker	635	11	1.73	2	0.31	4	0.63	6	0.94	0	0.00
家务及待业 Housework and unemployment	651	5	0.77	0	0.00	1	0.15	4	0.61	0	0.00
教师 Teacher	407	1	0.25	0	0.00	0	0.00	1	0.25	0	0.00
离退人员 Retiree	205	2	0.98	2	0.98	0	0.00	0	0.00	0	0.00
民工 Migrant worker	857	20	2.33	13	1.52	1	0.12	7	0.82	0	0.00
农民 Farmer	75 860	5 409	7.13	3 600	4.75	1 079	1.42	1 141	1.50	26	0.03
散居儿童 Scattered children	1 820	126	6.92	43	2.36	72	3.96	53	2.91	10	0.55
商业服务 Business services	517	3	0.58	1	0.19	1	0.19	1	0.19	0	0.00
学生 Student	20 588	1 638	7.96	343	1.67	516	2.51	1 092	5.30	59	0.29
医务人员 Medical worker	618	3	0.49	1	0.16	2	0.32	0	0.00	0	0.00
幼托儿童 Nursery children	5 065	238	4.70	47	0.93	135	2.67	94	1.86	26	0.51
其他 Others	587	17	2.90	4	0.68	6	1.02	7	1.19	0	0.00
文化程度 Education levels
文盲或半文盲 Illiteracy or semi-illiteracy	10 719	1 078	10.06	620	5.78	282	2.63	327	3.05	5	0.05
学龄前儿童 Preschool child	7 363	362	4.92	90	1.22	207	2.81	145	1.97	36	0.49
小学 Primary school	55 760	4 573	8.20	2 686	4.82	889	1.59	1 383	2.48	58	0.10
初中 Junior high school	26 974	1 338	4.96	611	2.27	389	1.44	510	1.89	21	0.08
中专或中技 Technical secondary school	1 531	25	1.63	13	0.85	7	0.46	9	0.59	0	0.00
高中 Senior high school	3 444	74	2.15	30	0.87	29	0.84	26	0.75	1	0.03
大专 College	1 576	19	1.21	3	0.19	12	0.76	6	0.38	0	0.00
大学及以上 University and above	854	6	0.70	3	0.35	2	0.23	2	0.23	0	0.00

Table 3

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