Parasitic enteritis in the free-ranging Common Myna Acridotheres tristis (Aves: Passeriformes: Sturnidae)

Two deceased adult Common Myna Acridotherestristispresented for post-mortem investigations revealed weak carcasses with pale mucus membranes. The small intestine was completely blocked by balled-up tapeworms, which wereconfirmed as Hymenolepiscantaniana. Grossly, the intestine showed severe, diffuse congestion and catarrhal enteritis. Histopathological examination of the intestine exhibited severe congestion, denuded epithelium with necrotic cells along with homogenous catarrhal exudates admixed with a few polymorphonuclear cells. This report puts into record a rare case ofHymenolepisspeciesincidence in Common Myna.


PLATINUM OPEN ACCESS
The Common Myna Acridotheres tristisis is an opportunist omnivore and can be easily spotted near human localities or grazing pastures (Feare et al. 2016). The maintenance of a high level of infection in mynas is associated with their feeding habits. These birds often feed insects which are usually the intermediate hosts for many helminthic infections (Caughley & Sinclair 1994). The myna has also been found to carry protozoan parasites like Haemoproteus and Plasmodium spp. (Ishtiaq et al. 2006). Various reports of mynas spreading the zoonotic diseases to humans (bird flu and salmonellosis), asthma, dermatitis etc. are also recorded (Young 2000). This communication highlights the presence of the parasitic tapeworm, Hymenolepis cantaniana, in a free ranging bird, precipitating the potentiality of disease transmission to domesticated birds.
Two adult Common Myna (1 male and 1 female) were brought to the Department of Veterinary Pathology for necropsy examination from Rajot, Baijnath Tehsil, Himachal Pradesh. On detailed necropsy examination the entire small intestine was found to be stuffed with balled-up dull white coloured tapeworms along with catarrhal exudate (Image 4). The collected cestode parasites were thin thread-like having average lengths of 1.84±0.13 cm. The proglottids of the tapeworms were collected carefully from the intestines (mainly duodenum and jejunum) of the birds, which were dorso-ventrally compressed between two slides and fixed in 10% neutral buffered formalin. After complete overnight washing, the worms were dehydrated in ascending grades of alcohol. The specimen were stained in borax carmine and then transferred to a clearing agent (cedar wood oil) and finally mounted in dextrine plasticised xylene (DPX) (Meyer & Oslen 1975).
Tissue sections of the intestine with a thickness of 5mm were collected in 10% neutral buffered formalin for histopathological investigation.
The formalin fixed tissues were processed, sectioned at 4-6 micron thickness and stained with Haematoxylin and Eosin (H&E) for microscopic evaluation as per the protocol described by Luna (1968).
A thorough external examination revealed emaciated carcasses with whitish to pale conjunctival mucus membranes. The morphological characteristics of the parasites recovered from the small intestine were studied in detail for identification of the genus of the cestode parasite. The detailed observation of the scolex, J TT Threatened Taxa and were in concordance to the findings of Demis et al. (2015). In a similar study, Ponnudurai et al. (2009) recovered tapeworms from Myna, which were later on identified as Railliettina species.
The histopathological examination of the intestine revealed the presence of severe congestion, necrotic cellular debris in the intestinal lumen, pyknotic changes and eosinophilic catarrhal exudate along with goblet cell hyperplasia and a few polymorphonuclear cells (Image 3). The observations are in concordance with the findings of Omer et al. (2015).
As this avian species frequently wanders around the backyard or organized poultry farms, consequently, may act as a potential source for pathogen transmission to the domesticated poultry and other birds by contaminating the feed or water with their droppings. The gross and histopathological studies revealed that severe emaciation due to catarrhal enteritis caused by H. cantaniana tape worms was most probably the cause of death in the Common Myna.