Although most cases of coronavirus disease 2019 (COVID-19) have occurred in low-resource countries, little is known about the epidemiology of the disease in such contexts. Data from the Indian states of Tamil Nadu and Andhra Pradesh provide a detailed view into severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission pathways and mortality in a high-incidence setting. Reported cases and deaths have been concentrated in younger cohorts than would be expected from observations in higher-income countries, even after accounting for demographic differences across settings. Among 575,071 individuals exposed to 84,965 confirmed cases, infection probabilities ranged from 4.7 to 10.7% for low-risk and high-risk contact types, respectively. Same-age contacts were associated with the greatest infection risk. Case fatality ratios spanned 0.05% at ages of 5 to 17 years to 16.6% at ages of 85 years or more. Primary data from low-resource countries are urgently needed to guide control measures.

Although most COVID-19 cases have occurred in low-resource countries, there is scarce information on the epidemiology of the disease in such settings. Comprehensive SARS-CoV-2 testing and contact-tracing data from the Indian states of Tamil Nadu and Andhra Pradesh reveal stark contrasts from epidemics affecting high-income countries, with 92.1% of cases and 59.7% of deaths occurring among individuals <65 years old. The per-contact risk of infection is 9.0% (95% confidence interval: 7.5-10.5%) in the household and 2.6% (1.6-3.9%) in the community. Superspreading plays a prominent role in transmission, with 5.4% of cases accounting for 80% of infected contacts. The case-fatality ratio is 1.3% (1.0-1.6%), and median time-to-death is 5 days from testing. Primary data are urgently needed from low- and middle-income countries to guide locally-appropriate control measures.

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The cellular immune responses of chickens inoculated with the vaccine strain S-1133 and/or a field isolate VA-1 of avian reovirus (ARV) were studied. Both strains of virus caused inhibition of the phytohaemagglutinin (PHA)-induced lymphoproliferative response of peripheral blood mononuclear cells (PBMC) and splenic mononuclear cells (SMC) during the initial stage from day 4 up to day 10 post-inoculation (PI), with a later return to the normal value. The inhibition in the PHA-induced lymphoproliferation of SMC could be partially overcome by depletion of adherent cells. The supernatant of the PHA-stimulated SMC culture was also checked in vitro for the presence of suppressive factor(s) produced in response to ARV infection. The culture supernatant from chickens at day 5 PI caused significant inhibition of the PHA-induced lymphoproliferation of control birds, suggesting the presence of suppressive factor(s). ARV infection also significantly inhibited IL-2 production on day 5. There was a significant increase in nitric oxide production by the splenic mononuclear cells of chickens inoculated with either strain of ARV.

A stability analysis was carried out using nine single crosses and fifteen diverse three-way crosses for nine traits across three locations