A team from Australia and Switzerland takes a look at the genomics of Aedes aegypti and Ae. albopictus mosquito populations in the Indo-Pacific region, uncovering distinct genetic differentiation patterns in the two invasive mosquito species. As they report in PLOS Neglected Tropical Diseases, the researchers did double-digest restriction-site associated (ddRAD) sequencing-based genotyping on nearly 500 Ae. aegypti or Ae. albopictus mosquitoes collected at more than two dozen sites in the Indo-Pacific, including sites in Saudi Arabia and Southeast Asia. Among other results, the authors found that Ae. aegypti mosquito populations were typically more genetically distinct as the distance between them increased, while Ae. albopictus populations tended to be more similar to one another, perhaps reflecting movement alongside human transport routes. "Genetic differences between Ae. aegypti populations were larger when populations were geographically distant," they write, "while differences between Ae. albopictus populations were larger when populations likely had limited access to human transportation."
Researchers from the US, Israel, Spain, and Cameroon describe strategies for profiling hepatitis viruses in the blood for a paper in PLOS One. Starting with unbiased metagenomic sequencing on samples from 99 infected individuals in Israel, for example, the team successfully generated full-length hepatitis C virus (HCV) sequences in 89 percent of the samples, along with partial sequences for a handful more, providing a look at the genotypes present in the population. From there, the authors relied on a targeted-enrichment and sequencing methods to characterize hepatitis B virus (HBV) and hepatitis D virus (HDV) infections, including those involving dual hepatitis infections. "[T]he high viral loads typical of HCV, and also with HDV, allowed us to readily obtain full genomes using standard methodology, whereas the low titers of HBV required enrichment," they note.
A Brazilian team explores tuberculosis (TB) risk in the context of host ancestry for another PLOS One study, focusing on individuals from the Brazilian Amazon. "In recent years, the incidence of tuberculosis has declined worldwide, although this disease still occurs at relatively high rates in Amerindian populations," the authors write — a pattern that prompted them to assess European, African, and Amerindian ancestry markers alongside TB susceptibility in 280 TB cases and 138 asymptomatic, TB bacteria-exposed controls at a Brazilian hospital. Compared with unaffected controls, the investigators note that active TB cases were more common in individuals with increased Amerindian ancestry and reduced European ancestry, though they caution that the current analysis did not have access to the data needed to take socioeconomic considerations and lifestyle factors into account.