Epidemiological characteristics of visceral leishmaniasis in China, 2017–2021

  Objective  To undersatnd the epidemiological characteristics of visceral leishmaniasis in China during 2017−2021, and provide evidence for the improvement of control strategy of visceral leishmaniasis in the future.

  Methods  The incidence data of visceral leishmaniasis cases reported in China during 2017−2021 were collected from the National Infectious Disease Reporting Information System of China for a descriptive analysis on the time, place and population distributions of the disease by using software Excel 2016, ARCGIS and SPSS .

  Results  During 2017−2021, a total of 1019 cases of visceral leishmaniasis, including 1 death, were reported in 278 counties of 103 prefectures in 23 provinces in China. The male to female ratio of the cases was 2.1∶1. The first six provinces reporting high case numbers were Shanxi (347, 34.1%), Gansu (238, 23.4%), Shaanxi (158, 15.5%), Xinjiang Uygur Autonomous Region (76, 7.5%), Sichuan (74, 7.3%) and Henan (46, 4.5%) with the cases reported accounting for 92.1% of the total nationwide. There were 7 counties reporting more than 30 cases of visceral leishmaniasis accumulatively, including 3 in Yangquan of Shanxi, 3 in Gansu, and 1 in Hancheng of Shaanxi. During 2017−2021, the reported cases number of visceral leishmaniasis in China declined first, then rapidly increased with the case number ranging from 164 to 239, the case number in Shanxi, Shaanxi and Henan showed obvious upward trends. The cases were reported in all age groups, mainly in age groups 0−5 years and over 61 years, accounting for 29.5% (301/1019) and 15.8% (161/1019) of the total, respectively. There was no obvious seasonal incidence peak of visceral leishmaniasis. Visceral leishmaniasisin mainly occurred during April-June. Farmers and scatteredly living children were the most vulnerable populations with cases accounting for 40.8% (416/1019) and 27.5% (280/1019) respectively. The differences in the incidence of visceral leishmaniasis were significant among different age groups (χ²=174.061, P<0.001) and among different populations (χ²=236.042, P<0.001).

  Conclusion  The incidence of visceral leishmaniasis was at a low level in some areas in China during 2017−2021. The cases were mainly sporadic, but epidemics occurred in some areas, affecting both the focus with continuous transmission and areas with new case importation. The incidence of visceral leishmaniasis increased rapidly and significantly in some areas in central and western China. The epidemic of visceral leishmaniasis in China should not be neglected, and there is a long way to go to control and eliminate the disease.