H1N1 influenza A outbreak among the Nicobarese, an aboriginal tribe of the Andaman and Nicobar Islands, India

Respiratory viruses among ethnic Nicobarese during COVID-19 pandemic

Background

Acute respiratory infections (ARIs) and severe acute respiratory illness (SARI) are public health burdens globally. The percentage of non-SARS CoV-2 respiratory viruses among patients having ARI and SARI who visit Car Nicobar's hospital settings is undocumented. Changes in the epidemiology of other respiratory viruses during COVID19 pandemic is being reported worldwide.

Methods

Inpatient and outpatient settings at BJR hospital, Car Nicobar Island, India, were used to conduct prospective monitoring for ARI and SARI among Nicobarese tribal members. The patients with ARI and SARI were enlisted in BJR hospital from June 2019 to May 2021. At the ICMR-NIV in Pune, duplex RT-PCR assays were used to test the presence of respiratory viruses. The prevalence of non- SARS CoV-2 respiratory viruses was measured by comparing here between pandemic and pre-pandemic periods.

Results

During the COVID19 pandemic, Influenza A (H3N2) and rhinovirus were predominantly reported non-SARS CoV-2 respiratory viruses while Human metapneumovirusand influenza A (H1N1)pdm09were most commonly reported in the prepandemic period. This result indicates the altered circulation of non-SARS CoV-2 during pandemic.

Conclusions

A considerable proportion of respiratory infection was correlated with respiratory viruses. Prevalence of non-SARS CoV-2 respiratory viruses was high at the time of infection when compared with pre-pandemic period, at Car Nicobar Island. This study enlightened the change in circulation of other respiratory viruses among the indigenous Nicobarese tribes. Clinicians and allied medical staff should be more prudent of these respiratory infections.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07435-x.

Emergence of influenza A (H1N1) PDM09 in the remote Islands of India--a molecular approach

BACKGROUND

A disease outbreak of A (H1N1) PDM09 was reported in Andaman and Nicobar islands in 2009 with an attack rate of 33.5% among settler population and 26.3% among the aboriginal Nicobarese tribe. During the ongoing outbreak of A (H1N1) PDM09 disease in different parts of the world, a subject working in Dubai city of Saudi Arabia, came to Port Blair, following which the pandemic triggered for the first time in these Islands.

MATERIALS AND METHODS

During the period August 2009 to January 2011, 30 confirmed cases of Influenza A (H1N1) PDM09 virus infection was detected. To understand the genetic relationship, the NA gene sequences of the viruses were phylogenetically analysed together along with the virus sequence isolated from other parts of the world.

RESULT

Formation of multiple clusters were observed, with the sequences of Andaman Islands, mainland India, Mexico, Saudi Arabia and few other counties clustering together. The sequence analysis data revealed that there was no specific mutation conferring resistance to oseltamivir among the Andaman A (H1N1) PDM09 virus isolates. The result of phylogenetic analysis have also revealed that the A (H1N1) PDM09 virus might have spread in these remote Islands of India via the subject from Saudi Arabia/Dubai.

CONCLUSION

A (H1N1) PDM09 Influenza outbreak have highlighted the need to strengthen the region-specific pandemic preparedness plans and surveillance strategies.