关键词: 内脏利什曼病, 病例调查, 白蛉密度, 犬感染率, 疫情调查

Abstract:

To investigate the origin of acquiring Leishmania infections and prevent the spread of visceral leishmaniasis, all cases with visceral leishmaniasis reported in Gaoping County, Shanxi Province from 2022 to 2023 which were recorded in the National Health Information System of China were subjected to case investigations, and host and vector surveys were performed in villages where visceral leishmaniasis cases lived. The sandfly density was investigated with light traps, and the serum anti-Leishmania antibody was detected in dogs with the rk39 immunochromatographic strips. In addition, foci disposal interventions were implemented in villages where the visceral leishmaniasis cases lived, including case finding, management of sources of infection, vector disposal and health education. During the period between 2022 and 2023, a total of 5 visceral leishmaniasis cases were reported in Gaoping County, Shanxi Province, and all were local cases, with main symptoms of fever, anemia and splenomegaly. The 5 cases were all adult males, and there were 3 workers and 2 farmers. The disease occurred throughout the year, and all cases lived in rural areas. A total of 608 sandflies were captured, with a mean density of 35.81 sandflies/(light•night), and a total of 244 domestic dogs were tested, with 24 dogs tested positive for anti-Leishmania antibody (9.8%). The vector Phlebotomus chinensis and dogs infected with Leishmania were detected in all villages where 5 visceral leishmaniasis cases lived. A total of 25 blood samples were collected from 5 cases’ neighbors, and all were tested negative for anti-Leishmania antibody. Foci disposal interventions included sacrificing of all 24 Leishmania-infected dogs, residual spray with deltamethrin insecticides for interior and exterior walls of visceral leishmaniasis cases’ houses and all sheep pens, dog houses and shabby cave dwellings in villages where cases lived (covering approximately 3 000 m²), 10 health education lectures pertaining to visceral leishmaniasis control knowledge and more than 5 000 poster foldouts pertaining to visceral leishmaniasis control knowledge in villages where cases lived. These findings indicate local transmission of visceral leishmaniasis in Gaoping County, with a high sandfly density and a high prevalence rate of Leishmania infections in dogs. Dog management and vector control are recommended to prevent the further spread of visceral leishmaniasis.

Key words: Visceral leishmaniasis, Case investigation, Sandfly density, Dog infection rate, Epidemic survey