In the present study, we assessed the pathogenicity of H5N8 avian influenza viruses belongs to the clade 2.3.4.4b in chicken. Birds of three different dose groups, 10 2 , 10 4 , and 10 6 EID 50 were used in the study. No mortality was observed in 10 2 EID0 group. Percent cumulative mortality of 10 4 and 10 6 EID 50 group was 66.67 and 100 %, respectively. Varying duration of MDT of 3.2 and 2 days was observed in 10 4 and 10 6 EID 50 group, respectively. The CID 50 of virus was found to be 10 4.5 EID 50 . High no. of viral RNA copies were found both in oropharyngeal and cloacal swabs and in various organs of birds infected in 10 4 and 10 6 EID 50 group. Significant gross and histological changes and presence of viral antigen in various organs were observed in 10 4 and 10 6 EID 50 group. So, the study concludes that Indian HPAI, H5N8 isolates are highly pathogenic in nature to chicken by affecting most organs systemically. CID 50 of this H5N8 virus indicates poor adaption in chicken and it implies poor transmission possibility of this virus for host species in field condition. Though this virus are highly pathogenic in nature as that of HPAI, H5N1 viruses, absence of endothelial staining in most organs attributes variation in replication process and pathogenesis from HPAI, H5N1 viruses. Hence, further studies need to be done to elucidate the pathobiology of this virus in various bird species. ### Competing Interest Statement The authors have declared no competing interest. Indian Council of Agricultural Research, https://ror.org/04fw54a43

African swine fever (ASF), a deadly disease caused by African swine fever virus (ASFV), emerged in north-eastern India in 2020 and subsequently spread to several states, devastating swine herds due to the lack of commercial vaccines. We report the isolation, genetic characterization and growth kinetics of ASFV isolated from Punjab, India in primary porcine pulmonary alveolar macrophages (PAM). Partial sequencing of the B646L gene categorized the virus as genotype II, showing complete nucleotide identity with previously reported Indian genotype II isolates. Phylogenetic analysis placed the isolate amongst genotype II ASFVs circulating in Europe and the Asia-Pacific region since 2007. Multistep growth curves were constructed based on HAD50 titres and viral DNA copy numbers after infection of PAM cultures at 1.0 and 0.1 multiplicity of infection (MOI) observed up to 168 hrs post-infection (hpi). At 1.0 MOI, viral titres and genome copy numbers in the cell associated (CA) fraction peaked earlier (120-144 hpi) before declining, whereas the culture supernatant (CS) fraction showed a delayed but sustained increase, reaching maximum levels at 168 hpi. At 0.1 MOI, both HAD50 titres and viral genome copies increased progressively in CA and CS fractions, with higher peak levels observed in the CS fraction at later time points. By observing up to 168 hpi, this study reveals higher extracellular virus production with lower DNA copy to HAD ratio in PAM cultures infected at 0.1 MOI, demonstrating optimal duration for higher virus yield in cell culture supernatants, which would support efficient ASFV propagation, pathogenesis and vaccine development studies.

Complete genome analysis of African swine fever virus isolated from a wild boar in Mizoram, India, revealed ≈99% nucleotide identity with those of domestic pig origin but with unique mutations. A One Health approach toward food security necessitates awareness among veterinary and public health professionals on virus evolution and domestic-wild pig transmission.

The study focused on developing an indigenous, one-step reverse transcription (RT)-PCR assay for detecting the porcine transmissible gastroenteritis virus (TGEV) genome. In summary, a gene construct and two sets of primers were designed by aligning N gene sequences from various TGEV strains, which were subsequently synthesized. The gene construct was sub-cloned into the pTZ57R/T vector, enabling the synthesis of in vitro transcribed (IVT) RNA, which served as a TGEV-positive control for RT-PCR protocol optimization. The assay optimization involved systematic testing of various parameters, including primer concentrations, magnesium (Mg++) levels, RNA template quantities, annealing temperatures, and other thermal variables. The analytical sensitivity was evaluated by examining serial 10-fold dilutions of IVT-RNA, both in actual form and when recovered from swine feces after spiking with the same dilutions of IVT-RNA. The developed assay demonstrated analytical sensitivities of 47.548 × 10² and 24.629 × 10³ RNA copies at 10-7 and 10-6 dilutions of IVT-RNA and spiked fecal RNA, respectively. Specificity was confirmed by testing against porcine epidemic diarrhea virus (PEDV), porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV), swine influenza virus (SIV), and known TGEV-negative swine fecal or rectal swab samples (n = 320) collected from the field. The assay exhibited specific amplification for TGEV without cross-reactivity to PEDV, PRRSV, CSFV, SIV, or field samples. This one-step RT-PCR assay proved to be both sensitive and specific for TGEV genomic detection, offering a reliable diagnostic tool for future outbreaks and subsequent monitoring of TGE.

Border disease virus (BDV) causes significant economic losses in sheep farming worldwide. In India, BDV has not yet been studied in sheep migrating for summer pasturing. This study aimed to determine the extent of BDV infection in migratory sheep and provide genetic characteristics of BDV. Blood and serum samples from 90 lambs of a migratory sheep flock (600) in Central India were collected and subjected to molecular detection, phylogenetic analysis and virus neutralization test (VNT). We detected BDV in two lambs through real-time RT-PCR, while 64.4% (58/90) of in-contact lambs had BDV neutralizing antibodies. One apparently healthy lamb was found to be persistently infected with BDV. Phylogenetic analysis of 5′-UTR and Npro genes and the concatenated datasets typed the BDV isolate from PI sheep as BDV-3 genotype. However, it showed a closer relationship with BDV-3 strains from China than the previously reported Indian BDV-3 strains. This is the first report on the detection of BDV persistently infected migratory sheep in India. Additionally, we provided evidence of genetic variability among BDV-3 strains in India. The findings improve our understanding of epidemiology and genetic characteristics of BDV in India and highlight the potential risks associated with the traditional practice of sheep migration for summer pasturing.

The present study on African Swine Fever (ASF) in Ranchi, Jharkhand demonstrates the mortality paĴ ern in diff erent age groups of pigs during an outbreak in 2022.The pigs were also examined for clinical signs before death and, gross and histopathology after death during months of August to September were analysed, and the mortality paĴ ern was correlated with the age of pigs at 15 days interval.Among diff erent age groups, the mortality in the starter (0-40 days) age group was lower (19.82%)during the initial phase of the outbreak compared to grower (41-120 days) and adult-fi nisher (≥121 days) which was 35.15% and 78.54% respectively on 15 th day.At 45 th day, the mortality reached 100% in the adult fi nisher group whereas it was 72.69% and 82.53% for starter and grower groups respectively.The grower and starter lot showed 93.23% and 92.17% mortality respectively by the end of the outbreak (60 th day) season.A comparative analysis of the overall mortality among diff erent breeds showed a non-signifi cant diff erence (p< 0.05).At necropsy, the prominent gross lesions were splenomegaly, haemorrhagic hepatic and mesenteric lymph nodes, epicardial and endocardial haemorrhages, haemorrhagic gastroenteritis, interstitial pneumonia, multifocal hepatic necrosis, and congested kidneys in most of the animals, where as renal petechial haemorrhages was observed in one pig which died later during the outbreak when mortality had subsided.Histopathologically, the lesions were renal tubular necrosis, hepatic sinusoidal congestion and vacuolar degeneration, massive congestion and haemorrhages in cortical and medullary areas of spleen and lymph node, heart showed haemorrhage and congestion with pyknotic changes in the cardiomyocytes.

The present study aimed to develop an in-house one-step reverse transcription (RT) PCR assay as a diagnostic preparedness for the detection of porcine epidemic diarrhoea virus (PEDV) in pigs. Primers and gene construct targeting the nucleoprotein gene of PEDV were designed and synthesised. In vitro transcribed (IVT) RNA synthesised from linearised plasmid DNA containing the gene of interest was used as the positive control for the development of the RT-PCR assay. The RT-PCR protocol was optimised using different concentrations of molecular reagents, the gradient of annealing temperatures and other thermal cycling conditions. Analytical sensitivity of the RT-PCR assay was determined using 10-fold serial dilutions of the IVT-RNA directly and of the RNA extracted from swine faeces spiked with the IVT- RNA. The developed RT-PCR assay had analytical sensitivity of 939 and 2682 RNA copies at 10-7 and 10-6 dilutions in IVT-RNA directly and RNA extracted from spiked faeces, respectively. The RT-PCR assay was found to be specific for PEDV, without any amplification for classical swine fever virus, swine influenza virus, porcine reproductive and respiratory syndrome virus and transmissible gastroenteritis virus. All the known negative field faecal samples (n=126) of pigs tested negative by the developed RT-PCR. The one-step RT-PCR assay developed in the present study will be highly useful in specific diagnosis of the disease in the event of its future ingression, and will also aid in monitoring of PED in Indian swine population.

During a routine surveillance for exotic and emerging swine viral diseases in India, five samples (four faecal, one serum) showed cytopathic effects in Vero cells. Transmission electron microscopy of infective cell supernatant revealed the presence of two types of virions. De novo metavirome sequencing enabled complete genome assembly of Mammalian orthorubulavirus 5 (MRuV5) and Mammalian orthoreovirus (MRV). The MRuV5 isolates possessed a whole genome of 15246 bp with seven genes (NP, V/P, M, F, SH, HN, L), while the MRV isolates had segmented genome with three large (L1, L2, L3), three medium (M1, M2, M3) and four small (S1, S2, S3, S4) segments. The MRuV5 isolates were genetically grouped with those from various mammalian species reported from South Korea and China. Deduced amino acid sequences of the HN, NP and F gene coding regions of MRuV5 isolates showed the substitutions of three (92L, 111R, 447H), two (86S, 121S) and two (139T, 246T) amino acids, respectively, compared to previously reported strains of the virus. However, they did not reveal any change in predicted amino acid residues at the receptor binding site in HN protein, cleavage site or HN stalk region. S1 gene of the MRV isolates showed the highest nucleotide identity (97.73%) with the MRV3 strain ZJ2013 isolated from pig in China, and these isolates were grouped into MRV type-3. Deduced amino acid sequences of MRV3 S1 gene revealed amino acid residues 198-204NLAIRLP, 249I, 340D, 419E known for sialic acid binding site and neurotropism. We report the co-infection of MRuV5 and MRV3 detected incidentally for the first time in domestic pigs in India. Although MRuV5 and MRV3 develop asymptomatic infections or mild disease in animals and humans, continuous monitoring of evolution and spread of such viruses is important in the current global scenario of increasing threats due to emerging novel pathogens.

Porcine Reproductive and Respiratory Syndrome (PRRS) is an important viral disease of swine that causes significant mortality in piglets and production losses in adult pigs. In this study, we investigated the protective efficacy of an inactivated PRRS virus vaccine candidate and evaluated the differences in PRRSV specific anamnestic response in piglets when challenged with live PRRSV at two different intervals post-immunization. Six-week-old piglets were immunized intramuscularly with an inactivated, Montanide ISA-206 adjuvanted Indian PRRSV isolate, followed by a booster dose at 21 days post-immunization. Homologous live PRRS virus challenge was done on 60 and 180 days post-booster (dpb). We assessed humoral and cell-mediated immune responses at various intervals post-immunization and after challenge. Viraemia, virus shedding in nasal secretions and lung lesion scores were studied to assess the efficacy of the vaccine candidate. All the immunized pigs developed PRRSV-specific antibodies upon booster dose administration. Neutralizing antibody (NA) titres before challenge, in most animals, ranged between 0 and 4. Potentially protective NA titre of 8 was observed in serum of seven out of the 12 immunized piglets after challenge, across the immunized groups. A significant increase in the mean T-helper, T-cytotoxic, memory or activated T-helper and NK cell populations was observed in immunized piglets challenged at 180 dpb, from 4 to 11 dpc, 5 to 11 dpc, 5 to 7 dpc and 6 to 11 dpc, respectively as compared to the challenge controls. Protective efficacy of the inactivated PRRSV antigen against the homologous virus challenge was evidenced by earlier onset of PRRSV specific virus neutralizing antibodies and cell mediated immune responses, reduced viremia, nasal virus shedding and severity of lung lesions in immunized piglets as compared to unimmunized controls post-challenge. Our results indicated that the inactivated PRRSV antigen elicited better virus specific anamnestic immune responses in piglets when challenged at six months after the single booster dose, due to age related increase in antigen-specific memory T helper cell responses, as compared to those challenged at 2 months post booster.

Background and Objective: Valsartan is an anti-hypertensive drug routinely used to treat patients with hypertension. It is a Type 1 Angiotensin receptor (AT1) receptor blocker and AT1 receptor blocker possess anti-neoplastic activity, hence the anti-cancer activity of this drug can be speculated. However also reports are showing pro-angiogenic and hence the pro-tumorigenic activity of valsartan, therefore the drug was envisaged for potential pro-tumorigenic activities. Materials and Methods: The effects of valsartan as a pro-angiogenic/anti-angiogenic molecule was tested in chicken embryos using an MCF-7 ductal carcinoma cell line. Post-treatment number of branch points as an indicator of angiogenesis were counted and histopathology was done. Statistical analysis was done using Tukey's HSD procedure to determine the difference in angiogenesis between the groups. Results: The result suggested that valsartan is a proangiogenic drug that enhances new blood vessel arborization and intussusceptive angiogenesis. The breach in vascular wall integrity was also observed post valsartan treatment that may serve for cancer cell metastasis. Conclusion: Valsartan shows proangiogenic activity and alter the normal structure of blood vessels that can attribute to cancer cell metastasis at least in the chicken chorioallantoic membrane model.

The aim of the present study was to understand the replication kinetics of an Indian isolate of highly pathogenic porcine reproductive and respiratory syndrome (PRRS) virus (Ind-297221) in MARC-145 cells infected at different multiplicity of infection (MOI) of 1.0, 0.1, 0.01 and 0.001. PRRSV titre in the infected cell fraction and the culture supernatant harvested at different intervals (12, 36, 48, 72, 96 and 120 h) post infection (hpi) was estimated by immunoperoxidase monolayer assay. Viral RNA copy numbers were quantified by TaqMan RT-PCR. PRRS virus could be detected first in intracellular fraction at 12 hpi in cells infected at 1.0 MOI, whereas in the extracellular fraction, earliest detection was at 36 hpi. Highest PRRSV titre of 1.3 × 105.0 TCID50/mL was achieved in 0.01 and 0.001 MOI groups at 96 hpi. Infection with 0.01 MOI resulted in the maintenance of maximum titre up to 120 hpi. The maximum viral copy numbers observed was 3.15 × 107.0 in 0.1 MOI group at 120 hpi in culture medium. The results of the study showed that MARC-145 cells infected with Indian PRRSV at 0.01 MOI and harvested in 96–120 hpi was found to be optimum for obtaining maximum virus yield and hence can be used for bulk propagation of the virus.

African swine fever (ASF), considered as the most dreadful swine disease due to its very high mortality, emerged in India in 2020. The complete genome analysis of ASF viruses isolated during the first outbreaks in India showed a few unique non-synonymous mutations in MGF 369-11L, MGF 505-4R, K205R and B263R genes. Frame shifts in the protein coding sequences were observed in DP60R, ASFV-G_ACD 00190, MGF 110-10-L-MGF110-14L fusion, MGF 360-14L and I267L genes of Indian ASF viruses as compared to ASFV/Georgia/2007. Complete genome based phylogenetic analysis of p72-genotype-II viruses showed the clustering of Indian isolates with ASFV/Wuhan/2019 in a separate clade. Phylogenetic analysis of concatenated sequences of 14 open reading frames (ORF) having single nucleotide polymorphisms (SNP) showed distinct grouping of Indian ASFVs with other Asian ASFVs. This is the first complete genome characterization of ASF viruses isolated from domestic pigs in India. The results indicate that number of Tandem Repeat Sequence (TRS) in the intergenic region between I73R and I329L genes, and the 14 ORFs with SNP reported in this study could be the genetic determinants to differentiate the closely related p72-genotype II viruses circulating in Asia.

During a surveillance study to monitor porcine epidemic diarrohoea virus and transmissible gastroenteritis virus in India, a total of 1043 swine samples including faeces (n = 264) and clotted blood (n = 779) were collected and tested. Five samples (four faecal and one serum) showed cytopathic effects in Vero cells. Transmission electron microscopy of infectious cell supernatant revealed the presence of two types of virions. Next-generation sequencing (de novo) allowed the complete genome sequence of mammalian orthorubulavirus 5 (MRuV5; 15246 bp) and that of all 10 gene segments of mammalian orthoreovirus to be determined. Genetic analysis of MRuV5 revealed grouping of the Indian MRuV5 with isolates from various mammalian species in South Korea and China, sharing more than 99% nucleotide sequence identity. The deduced amino acid sequences of the HN, NP, and F genes of MRuV5 isolates showed three (92L, 111R, 447H), two (86S, 121S), and two (139T, 246T) amino acid substitutions, respectively, compared to previously reported virus strains. Phylogenic analysis based on S1 gene sequences showed the Indian MRV isolates to be clustered in lineage IV of MRV type 3, with the highest nucleotide sequence identity (97.73%) to MRV3 strain ZJ2013, isolated from pigs in China. The protein encoded by the MRV3 S1 gene was found to contain the amino acid residues 198-204NLAIRLP, 249I, 340D, and 419E, which are known to be involved in sialic acid binding and neurotropism. This is the first report of co-isolation and whole-genomic characterisation of MRuV5 and MRV3 in domestic pigs in India. The present study lays a foundation for further surveillance studies and continuous monitoring of the emergence and spread of evolving viruses that might have pathogenic potential in animal and human hosts.

Edema factor (EF) is one of the major secretory proteins of anthrax bacteria along with protective antigen (PA) and lethal factor (LF). Edema factor is a calmodulin-and calcium-dependent adenylate cyclase that increases intracellular levels of cAMP. Intracellular trafficking of EF occurs through PA by binding to ATR/CMG2 receptors, which are also involved in other physiological functions of cells. cAMP is a secondary messenger which activates multiple signaling cascades involved in the cytokinetics of actin molecules and cell junction formation. The present study evaluated the effect of EF on growth and angiogenesis patterns in chicken embryos in the in ovo model. Angiogenesis in the chorioallantoic membrane (CAM) of an embryonated chicken egg was decreased and embryo growth was delayed by EF despite the absence of trafficking moiety PA, which is required for transferring the EF molecule inside the cell. Angiogenesis inhibition and embryo growth retardation indicate the use of an alternative receptor by EF to modulate these cellular functions. Additionally, docking was performed between EF as a ligand and hepatocyte growth factor receptor (cMET) and vascular endothelial growth factor (VEGF) receptors, which are mainly involved in growth and angiogenesis. The analysis revealed a very strong binding of EF to cMET receptor (in terms of the number of hydrogen bonds and energy) compared to its ligand hepatocyte growth factor (HGF), which indicates the use of cMET receptor by EF and induction of angiogenesis and embryo growth retardation possibly by competitive inhibition of HGF ligand or receptor-mediated endocytosis.

The study was aimed to evaluate the elicitation of highly pathogenic avian influenza (HPAI) virus (AIV) M2e and HA2-specific immunity in chicken to develop broad protective influenza vaccine against HPAI H5N1. Based on the analysis of Indian AIV H5N1 sequences, the conserved regions of extracellular domain of M2 protein (M2e) and HA2 were identified. Synthetic gene construct coding for M2e and two immunodominant HA2 conserved regions was designed and synthesized after codon optimization. The fusion recombinant protein (~38 kDa) was expressed in a prokaryotic system and characterized by Western blotting with anti-His antibody and anti-AIV polyclonal chicken serum. The M2e–HA2 fusion protein was found to be highly reactive with known AIV-positive and -negative chicken sera by ELISA. Two groups of specific pathogen-free (SPF) chickens were immunized (i/m) with M2e synthetic peptide and M2e–HA2 recombinant protein along with one control group with booster on the 14th day and 28th day with the same dose and route. Pre-immunization sera and whole blood were collected on day 0 followed by 3, 7, 14, 21, and 28 days and 2 weeks after the second booster (42 day). Lymphocyte proliferation assay by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) method revealed that the stimulation index (SI) was increased gradually from days 0 to 14 in the immunized group ( p < 0.05) than that in control chicken. Toll-like receptor (TLR) mRNA analysis by RT-qPCR showed maximum upregulation in the M2e–HA2-vaccinated group compared to M2e- and sham-vaccinated groups. M2e–HA2 recombinant protein-based indirect ELISA revealed that M2e–HA2 recombinant fusion protein has induced strong M2e and HA2-specific antibody responses from 7 days post-primary immunization, and then the titer gradually increased after booster dose. Similarly, M2e peptide ELISA revealed that M2e–HA2 recombinant fusion protein elicited M2e-specific antibody from day 14 onward. In contrast, no antibody response was detected in the chicken immunized with synthetic peptide M2e alone or control group. Findings of this study will be very useful in future development of broad protective H5N1 influenza vaccine targeting M2e and HA2.

The present experiment was conducted to study the role of cytokine, chemokine and TLRs responses of H9N2-PB2 reassortant H5N1 virus as compared to non-reassortant H5N1 virus isolated from crows in BALB/c mice. Two groups (12 mice each) of 6-8 weeks old BALB/c mice were intranasally inoculated with 106 EID50/ml of viruses A/crow/India/03CA04/2015 (H9N2-PB2 reassortant H5N1) and A/crow/India/02CA01/2012 (non-reassortant H5N1). At each interval, brain, lung and spleen were collected and relative quantification of cytokines, chemokines and TLRs was done by qPCR. The H9N2-PB2 reassortant H5N1 infected mice brain, the transcripts of TLR7 were significantly higher than other cytokines at 3dpi and KC was significantly upregulated at 7dpi. In non-reassortant H5N1 infected mice brain showed, TLR 7 and IFNα upregulation at 3dpi and IFNγ and TLR7 upregulation at 7dpi. The H9N2-PB2 reassortant H5N1 infected mice lung revealed, IL2 and TLR7 significant upregulation at 3dpi and in non-reassortant H5N1 infected mice, IL6 was significantly upregulated. At 7dpi in H9N2-PB2 reassortant H5N1 virus infected group mice, IL1 and TLR 3 were significantly upregulated in lungs and in non-reassortant group mice, IL1 and TLR7 were significantly upregulated. At 3dpi in H9N2-PB2 reassortant H5N1 virus infected mice spleen, IL4, IFNα, IFNβ were significantly downregulated and TLR7 transcript was significantly upregulated. In non-reassortant group mice, IL6, IFNα, IFNβ and TLR 3 were significantly upregulated. At 7dpi in H9N2-PB2 reassortant H5N1 virus infected mice spleen, IFNα, IFNβ and TLR7 were significantly lower than other cytokines and in non-reassortant group mice, IFNα and IFNβ were significantly downregulated. This study concludes that dysregulation of cytokines in lungs and brain might have contributed to the pathogenesis of both the viruses in mice.

African swine fever (ASF) is the most dreaded disease of pigs, which can cause mortality of up to 100%. Following disease outbreaks with high mortality in pigs in two states of north-east India, namely Arunachal Pradesh and Assam in early 2020, we confirmed the first occurrence of African swine fever (ASF) in domestic pigs in India by real-time PCR, virus isolation and nucleotide sequencing. Genetic analyses in three independent genomic regions (B646L gene encoding the p72 protein, E183L gene encoding the p54 protein and the central variable region (CVR) of B602L gene) showed that the Indian ASF viruses are similar to the post-2007-p72-genotype II viruses reported from Asia and Europe, suggesting the transboundary expansion of ongoing ASF outbreaks in the region.

Food and feeds contaminated with mycotoxins have been a threat to the rearing industry by causing some of the most fatal toxic reactions not only in the farm animals but also in humans who consume them. Toxicity to juvenile goats was induced by feed contamination with T-2 toxin (at 10 and 20 ppm dosage; group I and II, respectively). The toxicity impact was assessed on days 15 and 30 post treatment with respect to growth performance, oxidative stress, apoptotic studies and detailed pathomorphology. The study revealed that apart from the obvious clinical toxicosis (weakness, lethargy, and retardation in growth), the toxin fed groups also exhibited significant haematological (reduced hemoglobin, total leukocyte and thrombocyte counts) and biochemical changes (increased levels of oxidative stress markers with concomitant decrease in levels of serum and tissue catalase and superoxide dismutase). The pathomorphological and histological alterations suggested that the liver and intestine were the most affected organs. Ultra-structurally, varying degrees of degeneration, cytoplasmic vacuolations and pleomorphic mitochondria were observed in the hepatocytes and the enterocytes of the intestine. Kidney also revealed extensive degeneration of the cytoplasmic organelles with similar condensation of the heterochromatin whereas the neuronal degeneration was characterized by circular, whirling structures. In addition, the central vein and portal triad of the hepatocytes, cryptic epithelial cells of the intestine, MLNs in the lymphoid follicles, PCT and DCT of the nephronal tissues and the white pulp of the spleen exhibited extensive apoptosis. In this study, it was also observed that the expression of HSPs, pro-apoptotic proteins and pro-inflammatory cytokines were significantly upregulated in response to the toxin treatment. These results suggest that the pathogenesis of T-2 toxicosis in goats employs oxidative, apoptotic and inflammatory mechanisms.

We investigated the experimental infection of two highly pathogenic avian influenza H5N1 viruses isolated from crow (A/crow/Assam/142119/2008) and chicken (A/chicken/Sikkim/151466/2009) in house crows (Corvus splendens). Both viruses caused infection in crows, where four out of six and three out of six crows succumbed to H5N1 infection within 11 days post challenge by crow and chicken viruses, respectively. The major clinical signs in crows were wing paralysis, circling and torticollis. The virus shedding detected from swabs was not persistent in both crow nor chicken viruses. Both viruses were isolated more frequently from oral swabs than from cloacal swabs. Both virus strains were isolated from brain, lungs, heart, liver, pancreas, spleen, large intestines of crows that succumbed to H5N1 infection. The surviving birds seroconverted in response to H5N1 virus infection. Microscopically, both viruses caused coagulative necrosis in pancreas and kidneys. Brain showed gliosis and neuronal degeneration. This experimental study highlights that crows could be infected with H5N1 viruses from different hosts with minor differences in pathogenicity. Therefore, it is imperative to carry out surveillance of highly pathogenic avian influenza H5N1 virus in synanthropic birds along with biosecurity measures to mitigate the H5N1 spread in poultry population. Keywords: chicken virus; crow virus; highly pathogenic avian influenza; house crows.

In this study, we assessed the pathogenicity of two H5N1 viruses isolated from crows in mice. Eighteen 6-8 weeks BALB/c mice each were intranasally inoculated with 10(6) EID50/ml of H5N1 viruses A/crow/India/03CA04/2015 (H9N2-PB2 reassortant H5N1) and A/crow/India/02CA01/2012 (Non-reassortant H5N1). The infected mice showed dullness, weight loss and ruffled fur coat. Histopathological examination of lungs showed severe congestion, haemorrhage, thrombus, fibrinous exudate in perivascular area, interstitial septal thickening, bronchiolitis and alveolitis leading to severe pneumonic changes and these lesions were less pronounced in reassortant virus infected mice. Viral replication was demonstrated in nasal mucosa, lungs, trachea and brain in both the groups. Brain, lung, nasal mucosa and trachea showed significantly higher viral RNA copies and presence of antigen in immunohistochemistry in both the groups. This study concludes that both the crow viruses caused morbidity and mortality in mice and the viruses were phenotypically highly virulent in mice. The H5N1 viruses isolated from synanthropes pose a serious public health concern and should be monitored continuously for their human spill-over.