The clinical symptoms observed in the Bengal monitor lizards included anorexia, dullness, diarrhoea and weakness. One lizard died and was brought for necropsy and the visceral organs were examined (Fig 1). The stomach was found to be filled with the lizard’s own eggs that might have been eaten by it (Fig 2A) along with
Physaloptera sp. of nematodes (Fig 2B). The worms were firmly attached to the gastric mucosa causing erosive inflammatory foci and thickening (Fig 3). Diagnosis physalopteriasis depends upon identification of eggs in the faeces or on the presence of adult worms attached to the mucosa of the upper digestive tract. Species of the genus
Physaloptera occur in the stomach of many terrestrial vertebrates and the life cycles of several related species have been studied (
Hobmaier, 1941;
Schell, 1952;
Lincoln and Anderson, 1975). The lizards usually feed on crickets, grasshoppers, small snakes and ground beetles etc. The Bengal monitor lizards are also known to eat spiders, mites, scorpions and ticks (
Stebbins, 1985). It is not known which of these might serve as intermediate hosts for
Physaloptera sp. Many intermediate hosts scavenge on faecal materials of Bengal monitor lizards and ingest eggs present in the faecal matter, which hatch in their gut and migrate into body tissues for subsequent development to third stage larvae, which are infective to both definitive and paratenic hosts. Some findings report the recovery of the third stage larvae from invertebrate and vertebrate hosts including earwigs (
Schell, 1952); camel crickets (
Ceuthophilus sp.); grasshoppers (
Orphulella punctata,
Eutryxalisfilata and
Dzchroplus punctulatus); German cockroaches (
Blatella germanica) (
Petri, 1950); ground beetles (
Harpalus sp.)
(Schell, 1952) and prairie rattlesnakes (
Crotalus viridis) (
Widmer, 1970).
The microscopic examination of faecal samples revealed the presence of thick shelled larvated eggs. The gravid eggs contained pouch like organ in the female worms. The gravid egg pouches contained numerous closely packed eggs (Fig 4) that were thick walled (Fig 5). As the eggs of
Physaloptera sp. do not usually float on a standard faecal flotation (with a specific gravity >1.2), faecal sedimentation method is usually preferred.
The adult males of
Physaloptera sp. worm measure around 8-10mm long and 0.5mm in diameter with single lobed pseudolabium. Females are 12-24 mm long and 0.6 mm in diameter with two uteri, eggs are 52x34 µm in size and contained capsules (
Soulsby, 1982). In the study, both adult male worms and female
Physaloptera worms with gravid egg pouches (Fig 6) could be recovered. Histopathology revealed the presence of many immature and mature worms within a fibrous connective tissue capsule in the gastric sub-mucosa (Fig 7A and B). Profuse proliferation of fibrous tissue around the worms was observed in the gastric lamina propria (Fig 8A, B and C). Villous atrophy of intestine was seen along with demonstration of parasitic cross sections in the lumen (Fig 9). Well encapsulated parasitic sections were also seen in the liver and possibly were erratic migrations of
Physaloptera sp. worms through the hepatic tissue. Infiltration of eosinophils in the congested sinusoids was also seen (Fig 10).
In conclusion, the clinical signs observed, coprological analysis, gross and histopathological lesions are suggestive of
Physaloptera sp. nematodiasis in Bengal monitor lizards. Owing to the control measures, appropriate anthelmintic like pyrantel pamoate was given for other lizards. It should also include sanitation and extermination of the possible arthropod or paratenic hosts from the animal colony, coupled with diagnosis and treatment of the infection. It is hoped that this report will alert the wildlife veterinarians to the possibility of pathological conditions associated with
Physaloptera sp. infestation in reptiles.
