RESUMO
Background: Chikungunya disease (CHIKD) is a threat to global health, as it impairs the quality of life of an infected individual ranging from months to years. A systematic evaluation of the serological, virological, and immunological aspects of the circulating viruses and their impact on the host response is imperative for better understanding of the evolving disease dynamics. Methods: Serum samples were collected from 196 acute CHIKD patients from ten tertiary care hospitals across India during 2016-2021. Out of 196 patients, paired convalescent samples were collected from 51 patients (one-month post-onset of symptoms). The serum samples were profiled for cytokines and neutralisation capacity. Further, chikungunya virus (CHIKV) was isolated from the acute sera and the replication kinetics of the clinical isolates was evaluated. Findings: Serological analysis indicated that neutralisation could be correlated to seroconversion in the convalescent phase but not found significant in acute phase. In the acute phase samples, there was a correlation between elevated serum levels of IFN-γ, IP-10, MCP-1 and MIG and disease severity. During convalescent phase, pro-inflammatory markers such as IL-6, IL-1ß, IL-9 and IP-10 were found to be elevated with a corresponding decline in the secretion of anti-inflammatory cytokines such as IL-4 and IL-10, which correlated with persistent arthralgia. Analysis of replication of the clinical isolates revealed that 68.4% of viruses were fast-growing in the Vero cells (cytopathic effect [CPE] observed within 24 h post-infection), and their corresponding acute serum samples showed an elevated secretion of IFN-α, IL-1RA, IL-17F, IL-9, MCP-1 and MIP-1α. Interpretation: This study provides an important overview of neutralisation capabilities and cytokine responses along with virus pathogenesis associated with CHIKV infections in India. Funding: Biotechnology Industry Research Assistance Council (BIRAC).
RESUMO
The COVID-19 pandemic and public health response to the pandemic has caused huge setbacks in the management of other infectious diseases. In the present study, we aimed to (i) assess the trends in numbers of samples from patients with influenza-like illness and severe acute respiratory syndrome tested for influenza and the number and proportion of cases detected from 2015−2021 and (ii) examine if there were changes during the COVID-19 period (2020−2021) compared to the pre-COVID-19 period (2015−2019) in three states of India. The median (IQR) number of samples tested per month during the pre-COVID-19 period was 653 (395−1245), compared to 27 (11−98) during the COVID-19 period (p value < 0.001). The median (IQR) number of influenza cases detected per month during the pre-COVID-19 period was 190 (113−372), compared to 29 (27−30) during the COVID-19 period (p value < 0.001). Interrupted time series analysis (adjusting for seasonality and testing charges) confirmed a significant reduction in the total number of samples tested and influenza cases detected during the COVID-19 period. However, there was no change in the influenza positivity rate between pre-COVID-19 (29%) and COVID-19 (30%) period. These findings suggest that COVID-19-related disruptions, poor health-seeking behavior, and overburdened health systems might have led to a reduction in reported influenza cases rather than a true reduction in disease transmission.