In PLOS Neglected Tropical Diseases, a University of South Florida-led team takes a look at Plasmodium vivax malaria parasite populations in Southeast Asia. The researchers used whole-genome sequencing to profile nearly two dozen newly collected P. vivax isolates from the China-Myanmar border region, comparing the sequences to SNP profiles for hundreds more P. vivax samples from other parts of the Greater Mekong Subregion (GMS). Along with analyses focused on finding SNP markers in the malaria parasite populations, they tracked down genes that appeared to be subject to selection in P. vivax, while getting a glimpse at the broader population diversity patterns in the border region and beyond. "While P. vivax parasites from the entire GMS were substantially mixed with no evidence of significant gene flow barriers, those from the [China-Myanmar border] were more genetically distinct from other populations," they report, noting that "significant genetic sharing" in the border region may reflect clonal population expansions during malaria outbreaks.
Researchers from the UK, Brazil, and other international sites present findings from a genomic surveillance study of the yellow fever virus in São Paulo, Brazil for a paper in PLOS Pathogens. Using PCR-based screening, whole-genome sequencing, phylogenetics, phylogeographic analyses, and other approaches, the team characterized hundreds of samples collected from non-human primates in São Paulo from the fall of 2016 to early 2018. The animal vector-focused analysis pointed to three epizootic phases contributing to an outbreak in southern parts of São Paulo since mid-2016, starting with yellow fever virus lineages in northern parts of the state. "Our results shed light on the sylvatic [wild animal] transmission of [yellow fever virus] in highly fragmented forested regions in São Paulo state and highlight the importance of continued surveillance of zoonotic pathogens in sentinel species," the authors report.
For a paper in PLOS One, a team from Laos and France outlines a rapid genotyping strategy for dengue virus (DENV) surveillance, molecular epidemiology, and more. The "Genotype Screening Protocol," or GSP, method appeared to compare favorably with more extensive gene sequencing analyses for uncovering past introductions of the virus, the researchers report. Their GSP approach focuses on a region from the E gene of viruses from the DENV-2 serotype, they write, noting that infections involving DENV-2 have been on the rise in the Lao People's Democratic Republic. "Since 2008, DENV-2 circulated at a low level in Lao PDR, but its epidemiologic profile changed at the end of 2018," they write, adding that "confirmed DENV-2 cases suddenly increased in October 2018 and DENV-2 became predominant at the country level in early 2019."