Veterinary Parasitology, 17 (1984/85) 309--317 309 Elsevier Science Publishers B.V., Amsterdam --Printed in The Netherlands HISTOPATHOLOGICAL CHANGES IN THE PROVENTRICULUS OF FOWL GIVEN EXPERIMENTAL MONOSPECIFIC INFECTION WITH A CUARIA SPIRALIS K. RAMASWAMY* and R.K. SUNDARAM Parasitology Department, College of Veterinary and Animal Sciences, Mannuthy, Kerala State (India) (Accepted 26 October 1984} ABSTRACT Ramaswamy, K. and Sundaram, R.K., 1985. Histopathological changes in the proventri- culus of fowl given experimental monospecific infection with Acuaria spiralis. Vet. Parasitol., 17: 309---317. The pathological changes in the proventriculi of fowls given monospecific experimen- tal infection with Acuaria spiralis were characterized in the initial stages by an acute in- flammation due to the migration of 3rd and 4th stage larvae. There was a severe non- keratinizing squamous ceil metaplasia of the lining epithelium with pronounced granulo- cytic infiltration at 4--8 days post-infection. Multiple lymphoid nodules were evident in the lamina propria from 12 days post-infection. As the disease progressed there was ex- tensive fibroplasia in the organ. By 50--100 days post-infection pedunculated fibro- adenamatoid growths developed in the mucosa obliterating the entire lumen of the organ. A mortality rate of 29.16% of chicks (maximum on the 3rd week post-infection) was observed. INTRODUCTION Acuaria spiralis is a spirurid parasite inhabiting the proventriculus of fowl and other avian hosts. In natural infections it is found associated with severe proventriculitis (Allen, 1925; Cram, 1928; Koejan, 1934; Bump et al., 1947; Robijns, 1955; Hwang et al., 1961; Soulsby, 1965; Joshi and Kamala- pur, 1971; Nagy et al., 1977). A heavy infection with this parasite may result in death of the host (Cram, 1928; Edminister, 1947; Nescos, 1954; BendeU, 1955; Hwang et al., 1961; Soulsby, 1965; Karstad and Sileo, 1971). In sub-lethal infections a marked alteration in the constituents of the pe- ripheral blood is observed (Ramaswamy, 1977); with a marked eosino- phflia, pronounced lymphocytopaenia and a hypochromic anaemia. The parasites were also shown to cause great economic loss through poor weight gain, delayed sexual maturity, reduced egg production and decreased feed efficiency (Ramaswamy and Sundaram, 1981). The present study was aimed *Address all correspondence: Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, India. 0304-4017185]$03.30 © 1985 Elsevier Science Publishers B.V.