Seroprevalence of Dirofilaria immitis in Cats from Liaoning Province, Northeastern China

Hou, Honglie; Cao, Lili; Ren, Wenzhi; Wang, Dansheng; Ding, He; You, Juan; Yao, Xinhua; Dong, Hang; Guo, Yanbing; Yuan, Shuxian; Zhang, Xichen; Gong, Pengtao

Liaoning province is located in the northeastern of mainland China, covering an area of 148,000 km 2 and a population of 43.91 million approximately. Its geographical position is at east longitude 118˚53΄-125˚46΄ and at north latitude 38˚ 43΄-43˚26΄. The area has a continental monsoon climate, winter is longer than other seasons, and summer is warm. The average annual temperature is 7-11˚C, with a mean annual rainfall of 600-1,100 mm. There are 14 provincial cities distributed in Liaoning province, with the city of Shenyang as its capital ( The domestic cats for sample collection were selected according to the following criteria. First, cats had never been moved outside of the study area according to the owners. Second, animals were more than 6 months old. Third, animals must have no past history or diagnosis of heartworm infection. Finally, owners were willing to participate in this survey and authorized it. Meanwhile, the feral cats were collected from humane cat traps as follows. Humane cat traps containing food and water were set in shaded areas and checked the next morning. Trapped cats were transported to the Small Animal Hospital at Jilin University or Eastern Liaoning University. Then, they were anaesthetized, and a clinical exam was performed on each cat. A complete record of each cat was kept, including gender (male, female), age (< 3 or ≥ 3 years), rearing condition (domestic or feral) and other demographic data. The ages of the feral cats were estimated according to the teeth and bones of the layer [23] . Approximately 3-5 ml blood samples were obtained and centrifuged at