Molecular Detection and Genetic Diversity of Measles and Parainfluenza Viruses Circulating in Humans in Bangladesh: A...

Among Paramyxoviruses (PMVs), measles virus (MeV) and human parainfluenza virus (HPIV) are major contributors to respiratory tract infections worldwide. Despite recurrent outbreaks of MeV and the significant health impact of HPIV, data on their molecular epidemiology and genetic diversity in Bangladesh remain scarce. This study aimed to detect and genetically characterize circulating MeV and HPIV strains among humans to better understand their distribution and genetic diversity.

We conducted this study as part of Global One Health Surveillance between 2017 and 2019 across three communities and one hospital in Bangladesh. We enrolled community participants, who had the potential to harbor viruses, and hospital participants with Influenza-like illness (ILI). Survey data and biological specimens were collected to assess behavioral risk factors and virus spillovers. Samples were tested using consensus PCR, targeting the polymerase (pol) gene to detect PMV. Positive samples were confirmed by sequencing. Firth's logistic regression and phylogenetic analyses were used to evaluate associations and viral diversity.

Overall PMV prevalence was 1.2% (n = 10; 95% CI: 0.5-2.1), while MeV and HPIV were the same: 0.58% (n = 5; 95% CI: 0.2-1.3). MeV was found in participants having symptoms of ILI (5/508), while HPIV was detected both in ILI cases (3/508) and in asymptomatic individuals (2/354), respectively. The multivariable model showed MeV was significantly associated with participants' age, livelihood, and season, while no association was seen for HPIV. Phylogenetic analysis revealed MeV-D8 and B3, and HPIV-1, 2, 3 circulating regionally and clustered with Asian strains, suggesting continued viral transmission and evolution.

Our study provides molecular characterization of the circulation of diverse MeV and HPIV strains in humans across Bangladesh. Despite their endemicity, continued surveillance concerning vaccination coverage and genome sequencing is recommended to better understand the spatiotemporal dynamics of these key respiratory viruses in humans.