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Graphical abstract, Introduction Wild-type adult mice with intact interferon (IFN) system were neither susceptible to bluetongue virus (BTV) infection nor showed signs of morbidity/mortality. Establishment of immunologically competent wild-type adult mouse model with type I IFNs blockade is necessary to assess the pathogenesis, immune responses and testing of BTV vaccines. Objectives Present study aimed to establish and characterize BTV serotype 1 infection in immunocompetent adult mice with type I IFNs blockade at the time of infection by studying immune responses and sequential pathology. Methods Adult mice were administered with anti-mouse IFN-α/β receptor subunit-1 (IFNAR1) blocking antibody (Clone: MAR1-5A3) 24 h before and after BTV serotype 1 infection, and sacrificed at various time points. Sequential pathology, BTV localization by immunohistochemistry and quantification by qRT-PCR, immune cell kinetics and apoptosis by flow cytometry, and cytokines estimation by c-ELISA and qRT-PCR were studied. Results IFNAR blocked-infected mice developed clinical signs and typical lesions of BT; whereas, isotype-infected control mice did not develop any disease. The IFNAR blocked-infected mice showed enlarged, edematous, and congested lymph nodes (LNs) and spleen, and vascular (congestion and hemorrhage) and pneumonic lesions in lungs. Histopathologically, marked lymphoid depletion with “starry-sky pattern” due to lymphocytes apoptosis was noticed in the LNs and spleen. BTV antigen was detected and quantified in lymphoid organs, lungs, and other organs at various time points. Initial leukopenia (increased CD4+/CD8+ T cells ratio) followed by leukocytosis (decreased CD4+/CD8+ T cells ratio) and significantly increased biochemical values were noticed in IFNAR blocked-infected mice. Increased apoptotic cells in PBMCs and tissues coincided with viral load and levels of different cytokines in blood, spleen and draining LNs and notably varied between time points in IFNAR blocked-infected mice. Conclusion Present study is first to characterize BTV serotype 1 infection in immunocompetent adult mouse with type I IFNs blockade. The findings will be useful for studying pathogenesis and testing the efficacy of BTV vaccines.

Bluetongue (BT) is an economically important, non-contagious viral disease of domestic and wild ruminants. BT is caused by BT virus (BTV) and it belongs to the genus Orbivirus and family Reoviridae. BTV is transmitted by Culicoides midges and causes clinical disease in sheep, white-tailed deer, pronghorn antelope, bighorn sheep, and subclinical manifestation in cattle, goats and camelids. BT is a World Organization for Animal Health (OIE) listed multispecies disease and causes great socio-economic losses. To date, 28 serotypes of BTV have been reported worldwide and 23 serotypes have been reported from India. Transplacental transmission (TPT) and fetal abnormalities in ruminants had been reported with cell culture adopted live-attenuated vaccine strains of BTV. However, emergence of BTV-8 in Europe during 2006, confirmed TPT of wild-type/field strains of BTV. Diagnosis of BT is more important for control of disease and to ensure BTV-free trade of animals and their products. Reverse transcription polymerase chain reaction, agar gel immunodiffusion assay and competitive enzyme-linked immunosorbent assay are found to be sensitive and OIE recommended tests for diagnosis of BTV for international trade. Control measures include mass vaccination (most effective method), serological and entomological surveillance, forming restriction zones and sentinel programs. Major hindrances with control of BT in India are the presence of multiple BTV serotypes, high density of ruminant and vector populations. A pentavalent inactivated, adjuvanted vaccine is administered currently in India to control BT. Recombinant vaccines with DIVA strategies are urgently needed to combat this disease. This review is the first to summarise the seroprevalence of BTV in India for 40 years, economic impact and pathobiology.

Rabies is a zoonotic viral disease with inevitably fatal outcome. Toll-like receptor 3 (TLR3) could sense dsRNA viral infections, and implicated in pathogenesis of rabies and Negri bodies (NBs) formation. Present study was undertaken to elucidate the role of TLR3 in pathogenesis, NBs formation, and therapeutic potential of blocking TLR3/dsRNA interaction in rabies infection. Young Swiss albino mice were infected with 100 LD

Bluetongue (BT) is an infectious, non-contagious, insect-transmitted viral disease of sheep, other domestic, and wild ruminants caused by bluetongue virus (BTV), a prototype species of the genus Orbivirus of the family Reoviridae. The study was designed to determine the hematological and biochemical alterations and acute phase protein response in BTV sero-negative sheep experimentally infected with bluetongue virus serotype-10 and 24. The BTV-infected group comprising of 18 animals, 6 each inoculated with 6 ml of clarified virus containing 1 × 106/ml TCID50 of BTV-10 or 24 by intradermal route, 6 animals inoculated with equal volumes of BTV-10 and 24 and 4 animals with 6 ml of mock infected culture fluid served as uninfected control group. The blood and serum samples were analyzed at 0, 1, 3, 7, 11, and 16 days post-infection (DPI). Hematological findings in this study showed a significant decrease in the total number of white blood cells in BTV-10 infected group, a significant increase in circulating neutrophils decrease in lymphocytes in all the infected groups, in PCV in BTV-24 and co-infected groups, and RBC count in only BTV-24-infected group at 11 DPI. The results of serum biochemical analyses of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) exhibited increased levels in BTV-24 and co-infected animals. A significant rise in the serum level of creatine kinase (CK) was observed from 3 DPI in the infected groups. Serum levels of total proteins decreased significantly at 11 DPI in BTV-24 infected animals. Significant increase in CRP and fibrinogen levels was observed at 7 and 11 DPI in the infected groups. The significantly decreased levels of TLC, hemoglobin, PCV, CK, and acute phase proteins such as fibrinogen and CRP indicated the inflammatory changes associated with the virus replication and the consequent vascular damage and inflammatory changes in the tissues. Further, the variations in the hemato-biochemical and acute phase response observed between the two serotypes BTV-10 and 24 probes to the difference in virulence and pathogenesis of the serotypes in infected sheep.

The present study was aimed to evaluate the diagnostic efficacy of different techniques for detection of naturally occurring caprine paratuberculosis, considering histopathology as a parameter of infection. A total of 68 Gaddi goats slaughtered during September 2013 to March 2014 were investigated. Samples were screened for paratuberculosis by gross, histopathology, Ziehl-Nielsen (ZN) staining of impression smear and tissues sections (terminal ileum, ileo-caecal lymph node and mesenteric lymph node), ELISA, AGID and paraffin embedded tissue PCR. On gross, histopathology, ZN staining of impression smear as well as tissue sections from 68 goats revealed typical lesions, acid-fast bacilli and granulomatous inflammatory changes suggestive of paratuberculosis in 46.15% (18/39), 57.35% (39/68), 43.58% (17/39) and 35.89% (14/39) respectively. The sensitivity of ELISA, AGID and IS900/IS1311 paraffin tissue PCR was 74.35% (29/39), 61.53% (24/39) and 43.58% (17/39) respectively. All tests viz. histopathology, ZN staining, ELISA, AGID and paraffin embedded tissue PCR showed relatively higher sensitivity in animals with grade III and IV lesions when compared to grade I and II. Agreement among different tests was statistically analyzed by kappa statistics and chi-square test. The findings of the present study indicate that ELISA was most sensitive amongst the serological assays and histopathology was most sensitive of the post-mortem tests. However, combination of one of the serological tests along with histopathology and paraffin tissue PCR was found to be a better indicator for making confirmatory diagnosis of paratuberculosis in Gaddi goats.

Transplacental transmission (TPT) of wild-type Indian BTV-1 had never been experimentally proved. This study was first time investigated TPT of Indian BTV-1 (isolated from aborted and stillborn goat fetal spleens). The sequential pathology, virological and immune cell kinetics (CD4+, CD8+ T-lymphocytes and NK cells in spleen and PBMCs), and apoptosis in IFNAR1-blocked pregnant mice during early (infected on 1 GD) and mid (infected on 8 GD) gestation have been studied. There was higher rate of TPT during mid stage (71.43%) than early (57.14%) stage. In early stage reduced implantation sites, early embryonic deaths, abortions, and necro-haemorrhagic lesions had observed. Mid stage, congenital defects and neurological lesions in foetuses like haemorrhages, diffuse cerebral edema, necrotizing encephalitis and decreased bone size (Alizarin red staining) were noticed. BTV-1 antigen was first time demonstrable in cells of mesometrium, decidua of embryos, placenta, uterus, ovary, and brain of foetuses by immunohistochemistry and quantified by real-time qRT-PCR. BTV-inoculated mice were seroconverted by 7 and 5 dpi, and reached peak levels by 15 and 9 dpi in early and mid gestation, respectively. CD4+ and CD8+ cells were significantly decreased (increased ratio) on 7 dpi but subsequently increased on 15 dpi in early gestation. In mid gestation, increased CD8+ cells (decreased ratio) were observed. Apoptotic cells in PBMCs and tissues increased during peak viral load. This first time TPT of wild-type Indian BTV-1 deserves to be reported for implementation of control strategies. This model will be very suitable for further research into mechanisms of TPT, overwintering, and vaccination strategies.

Hepato-renal syndrome is a type of functional kidney failure due to acute or chronic liver diseases. A five year old female, crossbred goat was presented for post-mortem examination. On necropsy, icteric discoloration of carcass with enlarged liver, thickened jejunal and ileal mucosa and enlarged mesenteric lymph nodes were observed. Severe lipidosis of liver, hypertrophied hepatocytes, mononuclear cell infiltration of parenchyma and portal triads, fusion of villi, and extensive infiltration by mononuclear cells (epithelioid-macrophages, plasma cells and lymphocytes) and occasional giant cells were observed around a central caseated and calcified mass surrounded by fibrous tissue proliferation in the lamina propria of intestine. Calcification of the mesenteric lymph node was confirmed by Von Kossa staining as dark brown to black deposits. Severe glomerular and tubular degeneration, necrosis and presence of bile casts were observed in kidney, which was confirmed by Hall's staining. Diffuse golden yellow hemosiderin pigment deposits were observed in the splenic parenchyma, which wasconfirmedbyPerl's Prussianbluestainingasbluishblackpigments. Ziehl-Neelsenstainingrevealedacid-fastbacilli inthelamina propria of intestine. Immunohistochemistry (IHC) using anti-M. aviumsubspp. paratuberculosis immune serum showed positive brown signals intracellularly in the macrophages and epithelioid cells in the lamina propria of intestine. Demonstration of acid-fast organism and IHC confirmed paratuberculosisinfection and the cascade of injury consequent to the disease might have resulted in hepato-renal syndrome and death of the affected animal.

The present study was planned to investigate the pathology of terminal ileum and associated lymph nodes in Gaddi sheep in Himachal Pradesh (HP) with particular emphasis on paratuberculosis. The tissue samples were collected from 39 sheep slaughtered for table purpose around Palampur and from Government slaughter house Shimla, Himachal Pradesh, during September, 2013 to March, 2014. The terminal ileum, along with ileo-caecal junction (ICJ) and associated lymph nodes were critically examined at gross and histopathology for lesions suggestive of paratuberculosis. The scrapping smear cytology of ileal mucosa and ileo-caecal lymph node (ICLN) was stained by Ziehl-Neelsen’s (ZN) staining. Based on gross pathology, a total of 25(64.10%), 3(7.69%) and 1(2.56%) cases showed lesions suggestive of mild, moderate and severe paratuberculosis, respectively, with an overall 74.36% cases. ZN stained cytology demonstrated acid-fast bacilli (AFB) in 9 (23.08%) cases. On routine histopathological examination, the tissue samples were graded from 0 to IV and revealed only one (2.56%), 21 (53.84%), 13 (33.33%) and 3 (7.69%) Grade I, II, III and IV cases respectively, with an overall 97.43% cases. Only one histopathological Grade III case showed AFB (paucibacillary type) in ZN stained tissue sections from ileum and ileo-caecal lymph node (ICLN). Irrespective of the grade of paratuberculosis lesion the lymph nodes revealed mild to severe fibrosis in most of the cases suggesting replacement of granulomatous areas. In conclusion, histopathological examination was found to be the most effective method for detection of paratuberculosis in sheep and present study suggests alarming level of paratuberculosis among Gaddi sheep in HP.

In present study, pathological changes due to paratuberculosis, also known as Johne's disease, were described in apparently healthy Gaddi goats in Himachal Pradesh. Tissue including terminal ileum, ileo-caecal junction and associated lymph nodes were collected from 68 goats slaughtered for table purpose, and screened for lesions of paratuberculosis by performing Ziehl-Neelsen's (ZN) staining and gross/histopathological examination. Eighteen out of 68 goats showed gross lesions of paratuberculosis. Microscopic examination of affected tissues revealed lesions in 39 goats. The microscopic lesions were classified into four grades i.e., grade I (least severe) to IV (most severe) on the basis of infiltration of mononuclear cells consisting of lymphocytes, macrophages and epithelioid cells. Out of 39 goats, 9 (23.07%), 17 (43.58%), 9 (23.07%) and 4 (10.25%) showed lesions of grade I, II, III and IV, respectively. In addition, ZN staining of smears and/or tissue sections revealed acid fast bacilli (AFB) in 5 out of 17 grade II, 8 out of 9 grade III animals and all the 4 grade IV cases whereas, none of the grade I case was positive on ZN staining. Results of the study indicated that diagnosis of caprine paratuberculosis could be done on the basis of gross, microscopic lesions in the intestine and associated lymph nodes and demonstration of AFB in the affected tissues and smears using ZN staining. The present study puts on record the first report of paratuberculosis among Gaddi goats in HP.