Amerindian communities across southern Venezuela have remained isolated from Western medicine. Villages are often only accessible by river or air, and villagers rely on hunting and fishing for food. This isolation has a cost: These communities are among the last in the Americas to be affected by onchocerciasis, also known as river blindness. A parasite transmitted by black flies causes this condition, which can be treated by mass administration of the antiparasitic drug ivermectin. The Carter Center’s Onchocerciasis Elimination Program for the Americas (OEPA) has been delivering the drug across the Americas since 1993.
Now, an international research team has suggested that OEPA’s program may have had an unexpected impact by changing the microbiome of these isolated communities. Analysis of the microbiota living in and on the villagers showed that their diverse bacterial communities became more restricted and more alike to those seen in urban populations after just a handful of medical visits.
“The program offered a rare natural experiment,” said Maria G. Dominguez-Bello, a microbiologist at Rutgers University and coauthor of the new study, in a statement. “We know from studies in urban societies that antibiotics can have huge impacts on gut microbes,” she said. “But we didn’t know how even basic medicine might affect people with very limited exposure to medicine.”
Researchers from Dominguez-Bello’s group visited seven villages alongside the OEPA team in October 2015, before the medical program began, and again in February 2016. They collected over 1,500 samples from 335 participants, including fecal samples and swabs of the skin, nose, and mouth.
