RESUMO
COVID-19 caused by SARS-CoV-2 can develop the disease with different degree of clinical severity including fatality. In addition to antibody responses the antigen specific T cells may play a critical role in defining this protective immune response against this virus. As a part of a longitudinal cohort study in Bangladesh to investigate B and T cell specific immune responses, we sought to evaluate the activation induced cell marker (AIM) and the status of different immune cell subsets during infection. A total of 115 participants were analyzed in this study which included participants with asymptomatic, mild, moderate and severe clinical symptoms. In addition, healthy controls (19 in each group) were analysed. Specimens from participants collected during the pre-pandemic period were also analyzed (n=10). Follow-up visits were conducted on day 7, 14, and 28 for all the cases since the enrollment (day 1). In this study 10 participants among the moderate and severe cases expired during the course of follow up. We observed a decrease in mucosa associated invariant T (MAIT) cell frequency on the initial days (day 1 and day 7) in comparison to later days of the COVID-19 infection. However, natural killer (NK) cells were found to be elevated in symptomatic patients just after the onset of disease compared to both asymptomatic patients and healthy individuals. Moreover, we found AIM+ (both OX40+ CD137+ and OX40+ CD40L+) CD4+ T cells to show significant increase in moderate and severe COVID-19 patients in response to SARS-CoV-2 peptides (specially spike peptide) compared to prepandemic controls, who are unexposed to SARS-CoV-2. Notably, we did not observe any significant difference in the CD8+ AIM markers (CD137+ CD69+), which indicates the exhaustion of CD8+ T cells during COVID-19 infection. These findings suggest that the patients who recovered from moderate and severe COVID-19 were able to mount a strong CD4+ T cell response against shared viral determinants that ultimately induced the T cells to mount further immune responses to SARS-CoV-2.
RESUMO
BACKGROUND@#Food handlers can play a vital role into reducing foodborne diseases by adopting appropriate food handling and sanitation practices in working plants. This study aimed to assess the factors associated with food safety knowledge and practices among meat handlers who work at butcher shops in Bangladesh.@*METHODS@#A cross-sectional study was conducted among 300 meat handlers from January to March, 2021. Data were collected through in-person interviews using a structured questionnaire. The questionnaire consisted of three parts; socio-demographic characteristics, assessments of food safety knowledge, and food safety practices. A multiple logistic regression model was used to identify the factors associated with food safety knowledge and practices.@*RESULTS@#Only 20% [95% confidence interval, (CI) 15.7-24.7] and 16.3% (95% CI 12.3-20.7) of the respondents demonstrated good levels of food safety knowledge and practices, respectively. The factors associated with good levels of food safety knowledge were: having a higher secondary education [adjusted odds ratio (AOR) = 4.57, 95% CI 1.11-18.76], income above 25,000 BDT/month (AOR = 10.52, 95% CI 3.43-32.26), work experience of > 10 years (AOR = 9.31, 95% CI 1.92-45.09), ≥ 8 h per day of work (AOR = 6.14, 95% CI 2.69-13.10), employed on a daily basis (AOR = 4.05, 95% CI 1.16-14.14), and having food safety training (AOR = 8.98 95% CI 2.16-37.32). Good food safety knowledge (AOR = 5.68, 95% CI 2.33-13.87) and working ≥ 8 h per day (AOR = 8.44, 95% CI 3.11-22.91) were significantly associated with a good level of food safety practice.@*CONCLUSIONS@#Poor knowledge and practices regarding food safety were found among Bangladeshi meat handlers. Findings may help public health professionals and practitioners develop targeted strategies to improve food safety knowledge and practices among this population. Such strategies may include education and sensitization on good food safety practices.
