In PLOS Genetics, researchers from Israel, the UK, and Ethiopia compare genomic features in dozens of Leishmania donovani strains isolated from Ethiopian individuals affected by visceral leishmaniasis, alone or in combination with HIV. Based on whole-genome sequences for 41 isolates or clones — including 28 samples from northern Ethiopia and 13 southern Ethiopian samples — the team identified high levels of aneuploidy. While these ploidy patterns did not seem to coincide with parasite geography, the authors note, SNP and copy number profiles in most of the isolates did have apparent ties to southern or northern. "These differences are associated with distinct biological processes and molecular functions," they write, "and may be associated with genes involved in drug resistance and parasite survival."
A team from Zhengzhou University and Anhui Medical University takes a population genetics look at Thelazia callipaeda — a parasitic nematode worm that causes eye worm disease, or thelaziasis, in dogs, cats, and humans — for a paper appearing in PLOS Neglected Tropical Diseases. After doing targeted sequencing on a handful of marker genes in 32 T. callipaeda worms from 13 infected individuals in China, the researchers considered the parasite's broader genetic diversity and population structures using cox1 gene sequences in the Chinese isolates with those previously described in GenBank for samples in Europe and other parts of Asia. For that gene marker, they saw more modest population differences in China, Korea, and Japan than those observed between Europe and Asia, which appeared to be home to distinct T. callipaeda sub-populations.
German researchers reporting in PLOS One describe results from a phylogenetic study focused on Brachyspira pathogens behind swine dysentery. The team did PCR-based gene amplification and multi-locus sequencing typing on 116 B. hyodysenteriae isolates in fecal samples from symptomatic pigs at 100 farms in Germany from 1990 to 2016. Along with analyses of B. hyodysenteriae genes implicated in resistance to the antibiotics used to treat swine dysentery, the group uncovered two dozen new multi-locus sequence types. Even so, the authors note that the vast majority of isolates came from sequence types implicated in European swine dysentery cases previously. "Our data indicate that in Germany, swine dysentery might be caused by a limited number of B. hyodysenteriae clonal groups," they write.