Eight cases of canine thelaziosis found in two localities in Korea

Abstract

Thelazia callipaeda, a parasitic nematode that causes thelaziosis in various mammals, including humans, is known to be endemic in Korea. However, life cycle-related information on the parasite, primarily from human infection and a few dog cases, is limited. This study reports additional cases of T. callipaeda infections in dogs from both rural and urban areas in Korea, indicating the potential for transmission to humans and other animals. We collected 61 worms from 8 infected dogs from Paju and Cheongju Cities and observed their morphological characteristics under a light microscope. The findings indicate that T. callipaeda infections in animals in Korea may be underestimated and are distributed close to human environments. Our results contribute to the growing knowledge of the reservoir hosts of T. callipaeda in Korea and highlight the importance of continued surveillance and research to prevent and control this emerging zoonotic disease.

Keywords: Korea; Thelazia callipaeda; definitive host; dog; reservoir host; rural town.

Fig. 1

Thelazia callipaeda Railliet and Henry, 1910 detected in the conjunctiva of a dog from a rural town in Cheongju City (arrow).

Fig. 2

Photomicrographs of Thelazia callipaeda, recovered from dogs in the present study. (A) Anterior portion of female worm showing the uterus which is connected to the vulva located at the esophageal level. Bar=200 μm. (B) Anterior extremity of female worms showing well-developed buccal capsule. Bar=50 μm. (C) Encysted larvae in the uterus of female worms. Bar=100 μm. (D) The anterior portion of male worms. Bar=200 μm. (E) The posterior portion of male worms, showing the unequal size of spicules. Bar=500 μm.