Multi-site proficiency testing for validation and standardization of assays to detect specific pathogen-free viruses, coronaviruses, and other agents in nonhuman primates.

In efforts to increase rigor and reproducibility, the USA National Primate Research Centers (NPRCs) have focused on qualification of reagents, cross-laboratory validations, and proficiency testing for methods to detect infectious agents and accompanying immune responses in nonhuman primates. The pathogen detection working group, comprised of laboratory scientists, colony managers, and leaders from the NPRCs, has championed the effort to produce testing that is reliable and consistent across laboratories. Through multi-year efforts with shared proficiency samples, testing percent agreement has increased from as low as 67.1% for SRV testing in 2010 to 92.1% in 2019. The 2019 average agreement for the four basic SPF agents improved to >96% (86.5% BV, 98.9 SIV, 92.1 SRV, and 97.0 STLV). As new pathogens such as SARS coronavirus type 2 emerge, these steps can now be quickly replicated to develop and implement new assays that ensure rigor, reproducibly, and quality for NHP pathogen detection.

Co-infections of chickens with avian influenza virus H9N2 and Moroccan Italy 02 infectious bronchitis virus: effect on pathogenesis and protection conferred by different vaccination programmes.

Since the emergence of low pathogenic avian influenza (LPAI) H9N2 viruses in Morocco in 2016, severe respiratory problems have been encountered in the field. Infectious bronchitis virus (IBV) is often detected together with H9N2, suggesting disease exacerbation in cases of co-infections. This hypothesis was therefore tested and confirmed in laboratory conditions using specific-pathogen-free chickens. Most common field vaccine programmes were then tested to compare their efficacies against these two co-infecting agents. IBV γCoV/chicken/Morocco/I38/2014 (Mor-IT02) and LPAI virus A/chicken/Morocco/SF1/2016 (Mor-H9N2) were thus inoculated to commercial chickens. We showed that vaccination with two heterologous IBV vaccines (H120 at day one and 4/91 at day 14 of age) reduced the severity of clinical signs as well as macroscopic lesions after simultaneous experimental challenge. In addition, LPAI H9N2 vaccination was more efficient at day 7 than at day 1 in limiting disease post simultaneous challenge.RESEARCH HIGHLIGHTS Simultaneous challenge with IBV and AIV H9N2 induced higher pathogenicity in SPF birds than inoculation with IBV or AIV H9N2 alone.Recommended vaccination programme in commercial broilers to counter Mor-IT02 IBV and LPAIV H9N2 simultaneous infections: IB live vaccine H120 (d1), AIV H9N2 inactivated vaccine (d7), IB live vaccine 4-91 (d14).

Immunopathogenesis of infectious bronchitis virus Q1 in specific pathogen free chicks.

The immunopathogenesis of avian coronavirus, infectious bronchitis virus (IBV) Q1, was investigated in specific pathogen free chicks. Following infection, chicks exhibited respiratory clinical signs and reduced body weight. Oropharyngeal (OP) and cloacal (CL) swabs were collected at intervals and found to be RT-PCR positive, with a greater number of partial-S1 amino acid changes noted in CL swabs compared to OP swabs. In tissue samples, IBV viral load peaked 9 days post infection (dpi) in the trachea and kidneys, and 14 dpi in the proventriculus. At 28 dpi, ELISA data showed that 63% of infected chicks seroconverted. There was significantly higher mRNA up-regulation of IFN-α, TLR3, MDA5, LITAF, IL-1ß and IL-6 in the trachea compared to the kidneys. Findings presented here demonstrate that this Q1 isolate induces greater lesions and host innate immune responses in chickens' tracheas compared to the kidneys.