STUDIES ON THE PATHOLOGY OF ENDOPARASITIC DISEASES IN BACKYARD CHICKEN
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Date
2019-11
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SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517502. (A.P.) INDIA
Abstract
The present study is undertaken to know the incidence of endoparasitic
diseases in backyard chicken, to describe the lesions associated with the
diseases and to carry out morphological identification of parasites in possible
cases. A total of 1350 backyard chicken of either sex and of different age
groups procured from villages in and around Gannavaram apart from the
necropsies conducted in the Department of Veterinary Pathology, NTR C.V.Sc,
Gannavaram were examined for endoparasitic diseases, if any. Organs showing
parasitic lesions or parasites were collected for further studies. Thin blood
smears were prepared for detection of hemoprotozoan infection, if any.
Out of 1350 backyard chicken examined, 433 birds (32.07%) revealed
definite lesions of endoparasitic diseases in the gastrointestinal tract. Based on
gross and histopathological examination, the diseases were broadly grouped
under diseases caused by cestodes (4%), nematodes (11.7%), protozoa (16%)
and mixed infection (0.37%). No trematode and haemoprotozoa infection were
noticed. Morphological identification of various parasites was carried out in the
present study. Among cestodes, Cotugnia digonopora (1.48%) and Raillietina spp.
(2.52%) were found in the small intestines. Raillietina spp. comprised of R.
cesticillus (0.89%), R. echinobothrida (0.89%) and R. tetragona (0.74%).
In C. digonopora infection, intestines were pale and numerous
tapeworms were seen in the lumen on cut section. Histopathologically, sections
of tapeworms in the lumen and within the mucosa, blunting of villi, goblet cell
hyperplasia and infiltration of mononuclear cells were noticed.
In Raillietina spp. infection, segmented parasites were noticed in the
lumen of small intestine in all the three Raillietina spp. Histopathologically, cut
sections of parasites within the lumen of intestines and mononuclear cell
infiltration were seen in all the three species of Raillietina. In addition, in R.
cesticillus infection, villous hyperplasia and lymphoid depletion in the follicles
were noticed. Edema and hyperplasia of mucosal epithelium were seen with R.
echinobothrida whereas fusion of villi and necrosis were noticed in R. tetragona
infection. In the present study, Dispharynx nasuta (0.15%), Ascaridia galli
(11.11%), Cheilospirura hamulosa (0.07%), Heterakis gallinarum (0.15%) and
Tetrameres mohtedai (0.22%) were the nematodes noticed causing diseases in
backyard chicken. In D. nasuta infection, dark, circular areas were visible through the
serosa of proventriculus. The mucosa showed, ulcers and slender worms on the
surface. Histopathologically, cut sections of worms within the lumen,
metaplasia of the surface epithelium into stratified squamous type, infiltration
with mononuclear cells and lymphoid hyperplasia were the salient features
noticed. In A. galli infection, small intestines showed mild congestion of serosal
vessels in heavy infection. Slender roundworms were seen on cut section.
Microscopically, cut section of worms in the lumen of intestine, goblet cell
hyperplasia, blunting of villi and mononuclear cell infiltration were noticed in
the mucosa. In C. hamulosa infection, gizzard revealed erosions in the koilin layer
and reddish, coiled worms attached to underlying mucosa. Histopathologically,
cut sections of parasite, mucosal necrosis and severe infiltration of mononuclear
cells were observed along with lymphoid hyperplasia. H. gallinarum was found freely within the lumen of caecum. Microscopically, cut sections of worms, necrosis of mucosal epithelium along with mononuclear cell infiltration were noticed in the ceacum. T. mohtedai infection was seen in the proventriculus of chicken. Grossly,
dark spots were seen through the serosa and on cut section, reddish,
subspherical female worms of T. mohtedai were observed. Microscopically,
proventricular glands revealed cut section of the parasite and atrophy of
epithelium. In the present study, coccidiosis (16%) was the only protozoan disease
recorded that occurred as caecal (6.81%) and intestinal (9.19 %) forms. In both
the forms, the carcass was pale and emaciated. Mucosal scrapings from the
caeca and intestines revealed coccidial oocysts in caecal and intestinal
coccidiosis respectively. Based on micrometry and sporulation time, the
coccidia were identified as E. tenella in caecal coccidiosis and as E. acervulina,
E. necatrix, E. maxima, E. brunetti and E. mitis in intestinal coccidiosis.
Grossly, in caecal coccidiosis ballooning of caeca with dark petechiae with
bloody contents and dried caecal cores were seen on cut scetion.
Microscopically, extensive erosion of mucosal epithelium that contained
different stages of coccidia was a constant feature noticed. Haemorrhages,
fusion of villi and infiltration of mononuclear cells were seen.
Out of 124 birds affected with intestinal coccidiosis, concurrent infection
with five species of coccidia was seen in 98 birds that showed lesions
throughout the small intestines while 26 birds were infected with three species
of coccidia in which lesions were restricted to parts of small intestine. Grossly,
linear haemorrhages visible through the serosa and ballooning of intestines was
seen. On section, mucosa was haemorrhagic and the contents were bloody with
clots. Histopathologically, haemorrhages, necrosis, fusion of villi and
hyperplastic changes were noticed in the mucosa. Various developing stages of
coccidian in epithelial cells were observed along with severe infiltration of
macrophages, plasma cells and heterophils. In the present study, mixed parasitic infection (0.37%) that comprised of A. galli in combination with C. digonopora (0.22 %) and with R. Tetragona (0.15%) was noticed. In all the cases, intestines revealed both round worms and tapeworms in the lumen grossly and microscopically. In addition, necrosis (A. galli and C. digonopora) and hyperplasia (A. galli and R. tetragona) were also noticed in the mucosa microscopically.
The present study revealed 32.07% of endoparasitic diseases in backyard
chicken and recorded the associated pathological changes. Of the various
diseases noticed, coccidiosis was the most predominant in the area under study.
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