Host tissue reaction to Gnathostoma malaysiae (Nematoda: Gnathostomidae) in Rattus surifer Miller

The occurrence of adult Gnathostoma malaysiae in Rattus surifer and R. tiomanicus in Malaysia has been reported but there are no known reports on the host tissue reactions. This paper reports on the gross pathology caused by G. malaysiae in a red spiny forest rat, R. surifer and the tissue reactions caused. A tumor-like growth was located on the mid-stomach wall in a female rat captured in Gunung Bachock, Kelantan, Malaysia. This growth consisted of four tunnel-like structures containing sanguinopurulent fluid and leukocytes and this structure led into a central canal. The tissue surrounding the tumor was greatly inflamed and there was localized gastritis. The tunnel-like structure was surrounded by dense fibrotic tissue. The stomach wall was devoid of superficial epithelium and smooth muscle but mucinous glands were present. The midregion of the fibrotic scar contained eggs of G. malaysiae which had evoked a strong tissue reaction and were surrounded by pus. Blood vessels were empty, dilated and had undergone vasculitis and thrombosis.