Human infections with non-typhoidal Salmonella (NTS) serovars are increasingly becoming a threat to human health globally. While all motile Salmonellae have zoonotic potential, Salmonella Enteritidis and Salmonella Typhimurium are most commonly associated with human disease, for which poultry are a major source. Despite the increasing number of human NTS infections, the epidemiology of NTS in poultry in India has not been fully understood. Hence, as a first step, we carried out epidemiological analysis to establish the incidence of NTS in poultry to evaluate the risk to human health. A total of 1215 samples (including poultry meat, tissues, egg and environmental samples) were collected from 154 commercial layer farms from southern India and screened for NTS. Following identification by cultural and biochemical methods, Salmonella isolates were further characterized by multiplex PCR, allele-specific PCR, enterobacterial repetitive intergenic consensus (ERIC) PCR and pulse field gel electrophoresis (PFGE). In the present study, 21/1215 (1.73 %) samples tested positive for NTS. We found 12/392 (3.06 %) of tissue samples, 7/460 (1.52 %) of poultry products, and 2/363 (0.55 %) of environmental samples tested positive for NTS. All the Salmonella isolates were resistant to oxytetracycline, which is routinely used as poultry feed additive. The multiplex PCR results allowed 16/21 isolates to be classified as S. Typhimurium, and five isolates as S. Enteritidis. Of the five S. Enteritidis isolates, four were identified as group D Salmonella by allele-specific PCR. All of the isolates produced different banding patterns in ERIC PCR. Of the thirteen macro restriction profiles (MRPs) obtained by PFGE, MRP 6 was predominant which included 6 (21 %) isolates. In conclusion, the findings of the study revealed higher incidence of contamination of NTS Salmonella in poultry tissue and animal protein sources used for poultry. The results of the study warrants further investigation on different type of animal feed sources, food market chains, processing plants, live bird markets etc., to evaluate the risk factors, transmission and effective control measures of human Salmonella infection from poultry products.

Background:Newcastle disease (ND) and avian influenza (AI) are infectious and economically important diseases of poultry, and multiple factors including secondary viral and bacterial infections contribute significantly in the ND/AI pathobiology. The disease pattern during co-infections of genotype XIII NDV and AI is not well understood. So far, there has been no strong explanation for such difference in mortality and severity of clinical disease. In our present case study, we describe clinico-pathological disease condition of genotype XIII NDV and its co-infection with LPAI-H9N2 subtype, which could further helpful to understand the interactions of these two economically important poultry viruses. To address interaction of two respiratory infections, ND virus (NDV) and avian influenza virus (AIV), a total of 37 commercial poultry flocks were investigated in the southern peninsular India. Results:Clinicopathological as well as molecular biological investigations identified simultaneous circulation of NDV and AIV in same flock/bird. Sequence analysis of hemagglutinin and neuraminidase genes revealed that all identified AIVs were belonging to low pathogenicity H9N2 subtype whereas the analysis of the fusion genes revealed that detected NDVs belong to virulent type, and revealed that NDV strains currently circulating in India are belong to NDV class II, genotype XIII. The NDV alone as well H9N2 and NDV co-infected flocks exhibited clinical signs and lesions similar to that of virulent NDV except the degree of severity, which was higher in H9N2-NDV co-infected flocks. Furthermore, E. coli and mycoplasma were detected in all the ailing/dead birds from the co-infected flocks during progression of the clinical disease. Conclusion:The results demonstrate the importance of emerging fifth panzootic genotype XIII NDV in exacerbating clinical disease in vaccinated birds. The results not only present understanding on the virus-virus interaction and consequences on the bird's health but also highlight the multifactorial disease complexity in commercial poultry. Further studies are needed to investigate the molecular mechanisms of these interactions and their cumulative impact on the poultry health.

In this paper, we show how we developed a visualisation tool to challenge perceived notions about biosecurity on poultry farms. Veterinarians and veterinary public health professionals tend to present biosecurity measures as a universal and cost-effective solution for preventing and controlling diseases on farms. However, we illustrate how biosecurity is an ill-defined term, making it difficult to talk about or apply in practice. As a result, we demonstrate how we moved away from using the term biosecurity in our research by designing a visualisation tool. The tool was to allow us to open up dialogue around disease prevention and control, and make tangible the tacit situated practices of stakeholders working along the poultry supply chain. Our findings show that for those working along the poultry supply chain, the term biosecurity was either consistently open to interpretation, or too rigid to reflect or allow for local variations. We conclude by highlighting how our visualisation tool offers insights into why researchers must move beyond using biosecurity as a term, and instead envisage, design, and develop local solutions to prevent and control diseases on poultry farms.

The effect of vaccination of chickens with different inactivated vaccines against experimental Ornithobacterium rhinotracheale challenge was investigated. Eight different vaccines, with different inactivating substances (Formalin and thiomersal) and with or without adjuvant (mineral oil, alum and aluminium hydroxide gel), were produced. Following vaccination of experimental chickens at week 8 with formalin-inactivated mineral oil adjuvant bacterin, the mean O. rhinotracheale antibody titres rose to 5.88 2 log 21 days after primary vaccination and enhanced to a titre of 6.59 2 log 21 days after booster vaccination. The bacterin in mineral oil adjuvant induced the highest serologic response and a significant decrease of lesions such as air sacculitis and pneumonia in vaccinated birds compared with the unvaccinated challenge control birds. The bacterin in either alum or aluminium hydroxide gel adjuvant induced a moderate serologic response and a decrease of lesions compared with the unvaccinated challenge controls. The study showed that vaccination of layer chicken at the eighth week followed by a booster dose at the 12th week of age can effectively protect against O. rhinotracheale infections.

The study was carried out in 48 poultry flocks to elucidate the roles of various complicating pathogens involved along with Newcastle disease (ND)/ low pathogenic avian influenza (LPAI) outbreaks. Necropsy was conducted and samples were collected for the isolation of Newcastle disease virus (NDV), Influenza A virus, infectious bronchitis virus (IBV), pathogenic bacteria; molecular detection of infectious laryngotracheitis virus (ILTV), fowl adeno virus (FAV), chicken anaemia virus (CAV), Mycoplasma synoviae (MS) and Mycoplasma gallisepticum (MG). The isolation results confirmed that 18/48 flocks (37%) were positive for the presence of hemagglutinating agents. Out of 18 hemagglutination (HA) positive flocks, 11 flocks (61%) were positive for both avian influenza virus (AIV) and NDV; 4 flocks (22%) were positive for NDV; and 3 flocks (17%) were positive for AIV. Sequence analysis of hemagglutinin and neuraminidase genes of AIV revealed that all were belonging to LPAI-H9N2 subtype. Sequence analysis of F gene of NDV revealed that they belong to virulent type. The PCR results confirmed the presence of three to seven etiological agents (CAV, FAV, ILTV, MG, MS and avian pathogenic E. coli along with LPAI/NDV from all the 18 HA-positive flocks. The detection rate of triple, quadruple, quintuple, sextuple and sevenfold infections was 17% (3 flocks), 28% (5 flocks), 11%, (2 flocks) 28% (5 flocks) and 17% (3 flocks), respectively. In conclusion, the disease complex involved more than one pathogen, primarily resulting from the interplay between LPAI-H9N2 and NDV; subsequently this could be exacerbated by co-infection with other agents which may cause exacerbated outbreaks that may otherwise go undetected in field.