Pathological and molecular studies of the renal trematode Paratanaisia bragai in Indian peafowls (Pavo cristatus).

Endoparasitic diseases are commonly encountered in free-ranging birds. Although not all endoparasites cause disease, persistent infection with large numbers of parasites almost always affects normal physiological functions, leading to deleterious effects on the host. This paper describes the anatomopathological alterations caused by the renal trematode Paratanaisia bragai in Indian peafowl (n = 3) and examines the phylogeny of these and related parasites. Peafowl from forests in and around the Bareilly region, Uttar Pradesh, India, were necropsied, and microscopic and molecular investigations were performed. The peafowl were confirmed to be infected with P. bragai. Significant gross pathological lesions suggested nephrosis, and microscopic findings indicated a mild-to-moderate degree of nephrosis caused by the parasites in the tissue. The parasites were identified as P. bragai by histomorphological analysis of adult and eggs in the ureters, and the identification was confirmed by PCR and phylogenetic analysis. Nucleotide sequencing of the PCR products from the renal trematodes recovered from Indian peafowl revealed a close association with P. bragai from Columbiformes in the United Kingdom and Spain. The pathology and molecular epidemiology of parasitic diseases affecting peafowl is not well understood in India. This is the first report from India and the second report worldwide to document P. bragai infection in peafowl.

Baruscapillaria obsignata: a serious cause of enteropathy and high mortality in turkeys (meleagris gallopavo).

BACKGROUND: Capillariasis, an important parasitic disease of birds is caused at least by seven different genera of trichurid nematodes with clinical outcome ranging from mild enteritis to high mortality. OBJECTIVE: This study was aimed to investigate the causative agent involved in high mortality associated with severe enteric illness among turkey flocks in an organized commercial poultry farm at Bareilly, India. MATERIALS AND METHODS: Turkey carcasses (n = 119) and fecal samples from the affected deep litter pen constituted as the study materials. The disease was investigated by systematic necropsy, direct microscopy and histopathology. Representative samples were screened for other enteric pathogens. RESULTS: Microscopic examination of mucosal scraping revealed capillarid worms and their eggs in all the samples. The morphological features of adult worms were typically consistent to Baruscapillaria obsignata. Histopathology exhibited thickened muscular and mucosal layers, mononuclear and heterophilic infiltration in the lamina propria, blunting and clubbing of villi, epithelial denudation and sections of capillarid worms. Administration of levamisole at 80 ppm in drinking water reduced the mortality, clinical illness and worm load after three days of therapy. CONCLUSIONS: The capillarid worms in different avian hosts can cause different clinical manifestations and outcomes. From India, this is the first report describing intestinal pathology caused by B. obsignata in turkeys. We conclude that the B. obsignata infection is capable of causing life threatening enteropathy in turkeys and, hence, routine screening, scheduled deworming and good litter management are crucial to control the infection and its associated loss.

Prophylactic potential of resiquimod against very virulent infectious bursal disease virus (vvIBDV) challenge in the chicken.

The study evaluated the prophylactic potential of resiquimod (R-848), a synthetic TLR7 agonist, against very virulent infectious bursal disease virus (vvIBDV) infection in chicken. Specific pathogen free White Leghorn chicks of three week age were treated with R-848 (50µg/bird, intramuscular) or PBS (n=26/group). Twenty four hour later, half of the birds from each group were challenged with 10(5) ELD50 of vvIBDV and observed for 10days. To understand the effect of R-848, immune response genes such as interferon (IFN)-ß, IFN-γ, IL-1ß, IL-4, iNOS and TLR7 were analyzed at 24 and 48h post-challenge in PBMCs ex vivo by real-time PCR (n=6/group). On day 4 post-challenge, representative birds (n=3/group) were sacrificed to study the bursal damage and IBDV antigen clearance. Immunosuppression was assessed by antibody response against live Newcastle disease virus (NDV) vaccine, which was administered on day 10 post-challenge. R-848 pre-treatment significantly upregulated the transcripts of each immune response gene studied (P<0.05). There was 50% mortality on vvIBDV challenge in control birds, while it was only 20% with R-848 group. R-848 pre-treatment reduced the bursal damage as indicated by lower bursal lesion score in histopathology, reduced IBDV antigen signal in immunohistochemistry and improved antigen clearance in agar gel immunodiffusion test. Further, it protected significantly against vvIBDV induced immunosuppression as indicated by HI antibody titre. It is concluded that pre-treatment of R-848 conferred partial protection from mortality and bursal damage while complete protection against immunosuppression in chicken when challenged with vvIBDV, which could be due to the upregulation of immune response genes.