PATHOLOGY Division of Veterinary Pathology, Indian Veterinary Research Institute, Izatnagar, India The Occurrence of Nymphal Stage of Linguatula serrata in Water Buffaloes (Bubalus bubalis): Nymphal Morphometry and Lymph Node Pathology P. Sivakumar 1,3 , M. Sankar 2 , P. A. Nambi 2 , P. E. Praveena 1 and N. Singh 1 Addresses of authors: 1 Division of Veterinary Pathology, 2 Veterinary Parasitology, Indian Veterinary Research Institute, Izatnagar, India; 3 Corresponding author: Tel.: +91 9897 345982/+91 9412 192121; fax: +91 581 2303248; E-mail: sivavet@yahoo.co.in With 5 figures and 1 table Received for publication December 22, 2004 Summary The mesenteric lymph nodes (MLN) of buffaloes (n ¼ 100) were examined for the presence of parasitic infection. The nymphal stage of Linguatula serrata was observed in two buffaloes. A single white-coloured nymph with transversely striated spines on a segmented body, two pairs of oral suckers and hooks was observed in the MLN. The morphometrics of the nymphs were studied. The affected lymph nodes were grossly enlarged with cyst and showed pathological lesions of fibroblastic reaction with a mild underlying inflammatory zone. Introduction Water buffaloes are major dairy animals of traditional village farming systems significantly contributing to agricultural economy in Asian and African countries. Water buffaloes in India, which account for 50% of the total buffalo population in the world, produce 150 million tons milk and 10 million tons beef annually and provide draught power for agriculture and transport (FAO, 2001). The buffalo has been preferred to dairy cattle among the Asian countries, because of its adaptability to the hot tropics and its ability to perform optimally under relatively adverse environmental conditions. Despite the importance of buffaloes, there have been relatively few studies on them in relation to parasitic diseases having zoonotic importance. Linguatula serrata Frohlich, 1779, well known as Ôtongue wormÕ, is an aberrant cosmopolitan arthropod parasite, which infests the nasal sinuses and nasopharynx of carnivorous mammals belonging to the families of Canidae, Hyaenidae and Felidae (Khalil, 1970, 1973; Riley, 1986). Eggs of L. serrata are infective to a range of mammal intermediate hosts, particularly large grazing herbivores (Sachs et al., 1973). Linguatula serrata infection has been reported in most domestic and wild animals including cattle, sheep, goats, pigs, camels, lion, leopard, giraffe and kudu, and rodents (Sachs et al., 1973; Singh et al., 1973; Krishna et al., 1975; Muraleedharan and Zaki, 1975; Young, 1975). Human pentastomosis has also been reported in certain parts of the world, particularly in countries of the Middle East, America, Africa and in South-East Asia inclu- ding the Indian subcontinent (Roy and Ganguly, 1940; Lazo et al., 1999; Acha and Szyfres, 2003). Barring two reports, each one from Pakistan and Egypt (Choudhary and Dewan, 1967; Khalil, 1976), there was limited information on the occurrence of L. serrata in water buffaloes. This short communication reports the occurrence of the nymphal stage of L. serrata in water buffaloes, morphometrics of nymphs and pathology of affected lymph nodes. Materials and Methods Mesenteric lymph nodes (MLN), collected from water buf- faloes (n ¼ 100) slaughtered at the Bareilly slaughterhouse (North India), were examined grossly for pathological alter- ations and for the presence of parasites. The gross lesions and orientation of nymph in the cystic cavity, and nymphal morphometrics such as body size, number of abdominal segments, arrangement pattern of spines, and number of hooks and suckers were recorded. Based on these morpho- metric characteristics, the parasite was identified as the nymphal stage of L. serrata (Sachs et al., 1973; Riley, 1986). Pieces (0.5 cm thickness) of MLN preserved in 10% neutral-buffered formalin were embedded in paraffin blocks; sections of 4–5 lm thickness were cut and stained with haematoxylin and eosin. Results A single encysted nymph was observed in the MLN of two buffaloes (Fig. 1). These lymph nodes were grossly enlarged and oedematous. On cut section, a small cyst with haemor- rhagic surface filled with viscid fluid was observed in the medullar region. The size of the cysts was 0.6 and 0.4 cm in diameter respectively. The morphometric analyses of the nymphs are given in Table 1. The nymphs were greyish-white in colour measuring 4 and 3.4 mm in length respectively. Nymphs appeared tongue-shaped with an anterior swollen U.S. Copyright Clearance Center Code Statement: 0931–184X/2005/5210–0506 $15.00/0 www.blackwell-synergy.com J. Vet. Med. A 52, 506–509 (2005) Ó 2005 The Authors Journal compilation Ó 2005 Blackwell Verlag, Berlin ISSN 0931–184X