Spatiotemporal clustering analysis of seropositivity of key foodborne parasites in Dali Bai Autonomous Prefecture from 2019 to 2023

doi:10.12140/j.issn.1000-7423.2026.01.005

Abstract

Abstract:

Objective To systematically unravel the spatiotemporal distribution and clustering characteristics of seroprevalence of IgG antibodies against six major foodborne parasites in Dali Bai Autonomous Prefecture, Yunnan Province, based on serological testing data, so as to provide insights into precision diseases prevention and control. Methods Serum samples were collected from individuals admitted from Dali Bai Autonomous Prefecture Institute of Schistosomiasis Control from 2019 to 2023, and serum IgG antibodies against pathogens of six major zoonotic parasitic diseases were detected using enzyme-linked immunosorbent assay (ELISA) or colloidal gold immunochromatography, including taeniasis/cysticercosis, angiostrongyliasis, trichinosis, fascioliasis, echinococcosis, and paragonimiasis. Geographic distribution was visualized using the software ArcMap 10.8, and the overall spatial clustering pattern of IgG antibody seropositivity was identified using Moran’s I index within the study area. High-value (hot spots) and low-value (cold spots) clusters were identified with local statistics within the study area, and spatiotemporal scan analysis was performed with the software SaTScan 10.1 based on the Poisson model to identify spatiotemporal clusters of IgG antibody positivity against parasites. Results A total of 3 131 serum samples were tested from 2019 to 2023, and the overall seroprevalence of IgG antibodies against foodborne parasites was 23.3% (728/3 131) in Dali Prefecture, with seroprevalence of 52.5% (139/265), 50.5% (161/319), 26.7% (211/789), 14.6% (140/961), and 9.7% (77/797) from 2019 to 2023, respectively, appearing a tendency towards decline over years (χ² = 387.55, P < 0.01). Single infections were predominant (18.6%, 583/3 131), followed by dual infections (4.2%, 132/3 131). Counties with the three highest overall seropositivity included Yunlong County (53.2%, 58/109), Nanjian Yi Autonomous County (35.5%, 33/93), and Xiangyun County (32.7%, 33/101). The Moran’s I index was all negative each year from 2019 to 2023, ranging from -0.20 to -0.03, indicating no spatial autocorrelation in the seropositivity across years (all P > 0.05), which was consistent with a random spatial distribution pattern. Hotspot areas exhibited a random spatial distribution, with significant hotspots shifting from western regions (Yunlong County, Yangbi Yi Autonomous County) to central regions (Dali City) and then to eastern areas (Midu County) over time. Spatiotemporal scans identified two statistically significant clusters, including Heqing County (2021 to 2022, RR = 6.47, P < 0.01) and Weishan Yi and Hui Autonomous County (2021 to 2022, RR = 5.30, P < 0.01). Parasite IgG antibody-positive samples were primarily derived from farmers (86.1%, 627/728), males (59.1%, 430/728), and individuals at ages of 40 to 59 years (55.6%, 405/728), and no gender-, age- or occupation-specific seroprevalence was seen (χ² = 1.97, 7.73, 10.64, all P > 0.05). Conclusion The overall risk of foodborne parasitic infections declines in Dali Prefecture; however, the spatial pattern appears a complex landscape that is characterized by global randomness, local clustering, and dynamic shifts of hotspots. Differentiated, precision interventions are needed for long-term high-burden areas, anomalous clusters, and dynamic hotspots, and health education and behavioral interventions are prioritized for high-risk individuals, particularly farmers.

Key words: Foodborne parasitic disease, Seroprevalence, Spatial autocorrelation analysis, Spatiotemporal scan, Dali Bai Autonomous Prefecture

CLC Number:

R532

HAO Mingming, LI Rong, CHEN Ran, GAO Yuanyuan, DUAN Xiaoyun. Spatiotemporal clustering analysis of seropositivity of key foodborne parasites in Dali Bai Autonomous Prefecture from 2019 to 2023[J]. CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES, 2026, 44(1): 28-34.

Figures/Tables 4

Table 1

Table 2

Table 3

Population characteristics of individuals seropositive for foodborne parasite in Dali from 2019 to 2023

感染模式 Infection mode	阳性例数 No. positive	性别 Sex		年龄组/岁 Age group/Year					职业 Occupation
感染模式 Infection mode	阳性例数 No. positive	男 Male	女 Female	≤ 18	19~39	40~59	60~79	≥ 80	干部Officer	个体Dealers	工人Worker	教师Teacher	农民Farmer	学生Students
单一感染 Mono-infection	583	337	246	30	132	313	105	3	10	7	17	10	496	43
绦虫/嚢尾蚴 Tapeworm/Cysticercus	310	192	118	28	79	156	46	1	4	2	4	1	258	41
广州管圆线虫 Angiostrongy luscantonensis	14	6	8	0	2	12	0	0	1	0	0	1	12	0
旋毛虫 Trichinella	236	123	113	1	46	134	53	2	3	4	10	8	210	1
片形吸虫 Fasciola	3	1	2	1	0	0	2	0	0	0	0	0	2	1
棘球蚴 Echinococcus	19	14	5	0	4	11	4	0	2	1	2	0	14	0
并殖吸虫 Paragonimus	1	1	0	0	1	0	0	0	0	0	1	0	0	0
双重感染 Co-infection	132	85	47	5	25	83	18	1	0	1	3	1	119	8
绦虫/嚢尾蚴+广州管圆线虫 Tapeworm/Cysticercus + Angiostrongy luscantonensis	13	6	7	2	2	6	3	0	0	0	0	0	11	2
绦虫/嚢尾蚴+旋毛虫 Tapeworm/Cysticercus + Trichinella	97	66	31	2	17	67	11	0	0	1	1	1	91	3
绦虫/嚢尾蚴+棘球蚴 Tapeworm/Cysticercus + Echinococcus	12	7	5	0	4	5	2	1	0	0	2	0	9	1
绦虫/嚢尾蚴+并殖吸虫 Tapeworm/Cysticercus + Paragonimus	1	1	0	0	0	0	1	0	0	0	0	0	1	0
广州管圆线虫+旋毛虫 Angiostrongy luscantonensis + Trichinella	3	2	1	0	0	2	1	0	0	0	0	0	3	0
旋毛虫+片形吸虫 Trichinella + Fasciola	3	0	3	0	2	1	0	0	0	0	0	0	2	1
旋毛虫+棘球蚴 Trichinella + Echinococcus	1	1	0	0	0	1	0	0	0	0	0	0	1	0
旋毛虫+并殖吸虫 Trichinella + Paragonimus	2	2	0	1	0	1	0	0	0	0	0	0	1	1
多重感染 Multiple infection	13	8	5	0	1	9	3	0	0	0	0	1	12	0
绦虫/嚢尾蚴+广州管圆线虫+旋毛虫 Tapeworm/Cysticercus + Angiostrongy luscantonensis + Trichinella	6	4	2	0	0	4	2	0	0	0	0	0	6	0
绦虫/嚢尾蚴+旋毛虫+片形吸虫 Tapeworm/Cysticercus + Trichinella + Fasciola	1	0	1	0	0	1	0	0	0	0	0	0	1	0
绦虫/嚢尾蚴+旋毛虫+棘球蚴 Tapeworm/Cysticercus + Trichinella + Echinococcus	3	2	1	0	0	2	1	0	0	0	0	0	3	0
绦虫/嚢尾蚴+旋毛虫+并殖吸虫 Tapeworm/Cysticercus + Trichinella + Paragonimus	1	1	0	0	0	1	0	0	0	0	0	0	1	0
旋毛虫+片形吸虫+棘球蚴 Trichinella + Fasciola + Echinococcus	1	1	0	0	0	1	0	0	0	0	0	0	1	0
旋毛虫+片形吸虫+棘球蚴+并殖吸虫 Trichinella + Fasciola + Echinococcus + Paragonimus	1	0	1	0	1	0	0	0	0	0	0	1	0	0
合计 Total	728	430	298	35	158	405	126	4	10	8	20	12	627	51

Table 3

Table 4

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年份 Year	样品数 No. samples	阳性例数（率/%）No. positive (rate/%)	单一感染阳性数（率/%）No. positive of mono-infection (rate/%)	双重感染阳性数（率/%）No. positive of co-infection (rate/%)	多重感染阳性数（率/%）No. positive of multiple infection (rate/%)
2019	265	139（52.5）	98（37.0）	39（14.7）	2（0.8）
2020	319	161（50.5）	123（38.6）	36（11.3）	2（0.6）
2021	789	211（26.7）	166（21.0）	41（5.2）	4（0.5）
2022	961	140（14.6）	123（12.8）	13（1.4）	4（26.7）
2023	797	77（9.7）	73（9.2）	3（0.4）	1（0.1）
合计 Total	3 131	728（23.3）	583（18.6）	132（4.2）	13（0.4）

地区 Area	样品数 No. samples	阳性例数（率/%）No. positive (rate/%)	单一感染阳性数（率/%）No. positive of mono-infection (rate/%)	双重感染阳性数（率/%）No. positive of co-infection (rate/%)	多重感染阳性数（率/%）No. positive of multiple infection (rate/%)
宾川县 Binchuan County	86	22（25.6）	18（20.9）	4（4.7）	0（0）
大理市 Dali City	1 236	170（13.8）	152（12.3）	13（1.1）	5（0.4）
洱源县 Eryuan County	1 000	217（21.7）	170（17.0）	44（4.4）	3（0.3）
鹤庆县 Heqing County	114	18（15.8）	15（13.2）	2（1.8）	1（0.9）
剑川县 Jianchuan County	97	30（30.9）	17（17.5）	13（13.4）	0（0）
弥渡县 Midu County	77	10（13.0）	10（13.0）	0（0）	0（0）
南涧彝族自治县 Nanjian Yi Autonomous County	93	33（35.5）	23（24.7）	9（9.7）	1（1.1）
巍山彝族回族自治县 Weishan Yi and Hui Autonomous County	424	78（18.4）	65（15.3）	11（2.6）	2（0.5）
祥云县 Xiangyun County	101	33（32.7）	27（26.7）	5（5.0）	1（1.0）
漾濞彝族自治县 Yangbi Yi Autonomous County	118	35（29.7）	24（20.3）	11（9.3）	0（0）
永平县 Yongping County	76	24（31.6）	21（27.6）	3（3.9）	0（0）
云龙县 Yunlong County	109	58（53.2）	41（37.6）	17（15.6）	0（0）

年份 Year	莫兰指数 Moran’s I	方差 variance	Z得分 Z-score	P 值 P-value	空间模式 Spatial Pattern
2019	-0.14	0.04	-0.24	0.81	随机Random
2020	-0.20	0.03	-0.64	0.52	随机Random
2021	-0.03	0.03	-0.34	0.73	随机Random
2022	-0.05	0.03	-0.19	0.85	随机Random
2023	-0.16	0.03	-0.10	0.92	随机Random
2019—2023	-0.02	0.04	-0.35	0.72	随机Random