As poultry are the main supplier of eggs and meat and majority of the people of Assam are non-vegetarian therefore, poultry rearing now a days becomes very popular in Assam, which acts as a good source of income especially for the rural people. In India total population of poultry is 851.81 million where 317.07 million is total backyard poultry and 534.74 million is total commercial poultry in the country. Out of this, Assam shares around 46.7 million poultry population¹. However, the organized as well as the backyard farms frequently suffer from various setbacks like bacterial, viral and parasitic infections. As a result, the farmers are not achieving desired economic return. Among the poultry parasite, nematodes are the most important group of helminth parasites. Ascaridia galli, which causes ascariasis is the most common worm found especially in free ranging birds causing great economic losses in modern poultry². Along with chicken A. galli also affects turkey, duck and goose³. The different ways of severe economic losses due to A. galli are loss of weight gain, meat production, egg production and death of birds⁴. Therefore, in an outbreak of ascariasis in a farm early diagnosis is very much essential to follow proper therapeutic measures to save the birds. This paper describes clinical signs, pathology, diagnosis of ascariasis and identification of A. galli based on the morphological characteristics of the worm isolated from a carcass of Kamrupa fowl died in a farm of Lakhimpur district of Assam.

Carcass of a male Kamrupa fowl (Kamrupa fowl is a new dual purpose chicken variety which was developed under AICRP on Poultry Breeding, Directorate of Research (Vety.) Assam Agricultural University, Khanapara, Guwahati) aged 303 days was brought to the Department of Veterinary Pathology, Lakhimpur College of Veterinary Science, AAU, Joyhing, North Lakhimpur for post mortem examination. The owner reported history of retarded growth, anorexia and drowsiness. Detailed post mortem examination was conducted with thorough examination of all the visceral organs viz. heart, lung, liver, spleen, kidney and intestine. Part of intestine where parasites were lodged was collected and preserved in 10% formalin solution. The tissue samples were processed routinely and the paraffin embedded tissue sections were cut at 5 µm and stained with Haematoxylin and Eosin⁵. Similarly, one part along with the parasites was sent to Department of Parasitology for identification of the species of the worm (Ascaridia). Mucosal scraping from the caecum was collected and diluted with saline on a slide and covered with a cover slip and examined under microscope to see the presence of coccidia.

Post-mortem examination revealed that the carcass was highly emaciated, keel bone was very prominent and overall body condition was very poor. A tangled mass of worms Ascaridia occluded the intestinal lumen (Fig. 1). The intestine was hyperaemic and showed catarrhal enteritis. The wall of the intestine was thickened and these changes were in accordance with the earlier findings². The kidneys were slightly pale and other organs were almost normal in appearance.

Caecal scraping examination under microscope revealed absence of coccidia parasite. As per author⁶A. galli can also exhibit pathological effects through interactions with some other diseases like coccidiosis and infectious bronchitis.

Microscopic examination of the affected parts of intestine showed degeneration and necrosis of the mucosal epithelial cells of the intestinal villi. Some of the villi became shorter and broader due to sloughing of the necrosed tissues (Fig. 2). There were some areas of infiltration of large numbers of mononuclear cells and few polymorphonuclear cells in the mucosa and submucosa (Fig. 3). Cytoplasmic vacuolar degeneration was seen in some villous and glandular epithelial cells. Similarly authors^2,7,8 also recorded similar type of findings in ascariasis infected tissues of fowl caused by A. galli.

The intestinal nematode parasites recovered at necropsy was identified as Ascaridia galli on the basis of their morphological characters. The oral opening was surrounded by 3 trilobed lips at the anterior end (Fig. 5) and the body was distinctly striated. Oesophagus was without a posterior bulb. All these characters are in accordance with authors^9,10. The studies of author¹⁰ stated that in case of A. galli location of the anus is just anterior to the tail end in female and the tail is straight and provided with a caudal spine. In the present study all these morphological features were observed (Fig. 6). In A. galli the male measures 50-76 mm and females 76-116 mm in length⁹. The male specimen in the present study measured 57 mm approximately which was well within the previous findings⁹ and was whitish in colour (Fig. 4). The ova examined under low power (x10) in the present study was oval in outline, smooth shelled and unsegmented which was similar as stated by author⁹ (Fig. 7).

Therefore, through post mortem examination of a bird died due to A. galli infection we can easily diagnose a case of ascariasis in a farm which is very much essential to follow proper therapeutic measures. Along with following strict biosecurity measures, good farm management and timely diagnosing the cause of mortality farmers can protect the birds in a farm.

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