The Molecular Epidemiological Study And Pathology Of Leishmania Infection In Dogs In Sichuan Epidemic Area

Visceral leishmaniasis (also known as Kala-azar) is an important zoonotic parasite disease which infected by Leishmania donovani complex and caused liver and spleen enlargement. The disease is not only widely distributed in the world, also affected16cities along Changjiang River in China from1880s, Sichuan concluded. Geomorphic of most areas in Sichuan has been changed in Wenchuan earthquake, and quantities of dogs as source of infection wandered around. Meanwhile, palindromia and infection rate rised in these disaster areas. So it is important to get a precise diagnostic method to make a sense of epidemiology of canine leishmaniasis in epidemic areas of Sichuan.This study investigated the prevalence of Leishmania DNA in584venous blood sample of dogs from Wenchuan, Maoxian, Heishui, Beichuan and Jiuzhaigou County, which are all endemic areas of zoonotic VL, detected by real-time quantitative PCR. The total positive detection rate is18.1%, while all the fives areas’rates are as followed: Heishui26.3%, Wenchuan24.7%, Jiuzhaigou24.6%, Maoxian12.3%, Beichuan8.3%. The dogs were further allocated to different groups based on sexes and ages. It was revealed that age is significantly associated with prevalence of Leishmania in dogs. Then twelve high positive rate dogs were raised separately in different animal rooms in Sichuan Agriculture University to make a further research. When dogs dead naturally, the main anatomical lesion manifested that spleen, liver and lymph nodes took on different degrees of swelling and soft texture, especially numbered HS78dog’spleen surface provided with some small nodules. Then pathological section were made using dogs tissues just like liver, spleen, heart, kidney and lung, and all the tissues take on some extent of pathological changes, especially spleen and liver. Congestion can be found in spleen and only a few lymphocytes around the central arteriole, while macrophage swelling and increased. Besides, leishmania amastigotes was found in HS78dog’splenic macrophages. Hepatic sinusoid was congestion, cells vacuolar degeneration and kupffer’s cells swelling and increased. Endothelial cell of a dog kidney tubule was degeneration, necrosis and defluvium, and interstitial vascular was congestion. Most of the dog heart myocardial fiber dissolution or fracture, and visible diffuse congestion can be found in lung. It takes12days after vitro culture until leishmania promastigotes can be found under microscopic using spleen and liver tissue of dog numbered HS78.Prevalence of canine leishmaniasis in Sichuan disaster area take on a little reduction in2010compared with2009date made by Qu Jin-hui, and it suggests the effective prevention measure taken on by Sichuan government dealing with dogs which is the main source of infection. Pathological section observation of spleen and liver is a scientific diagnostic method of Kala-azar. All the survey can predict the tendency of visceral leishmaniasis in Sichuan, and will be helpful for prevention.