Intestinal parasitic worms were historically a problem for people in the U.K, and those who lived in the British Isles during the Roman (43 A.D. to circa 140 A.D.) and late medieval periods (11th to 16th centuries) suffered the most from these harmful organisms, according to a new study.
Zoologists and archaeologists teamed up and examined the remains of more than 400 individuals who lived in the U.K. from prehistoric times to the Victorian era, to investigate how these parasitic infections changed over time in the U.K. The researchers hope that their findings will inform the fight against parasites today, particularly in tropical and sub-tropical regions of the world.
"Defining the patterns of infection with intestinal worms can help us to understand the health, diet and habits of past populations," study co-first authors Hannah Ryan, an archaeologist, and Patrik Flammer, a zoologist both at the University of Oxford, said in a statement. "More than that, defining the factors that led to changes in infection levels (without modern drugs) can provide support for approaches to control these infections in modern populations."
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The eggs of intestinal parasitic worms, such as nematodes and whipworms, are frequently found during archaeological excavations, as their eggs often remain intact and the various species are easily identified by their shapes, even after thousands of years, the researchers reported in the study. Moreover, the presence of these eggs is usually a good indicator that adult parasites had infected a host, in this case the hundreds of human remains analyzed in the study.
The researchers studied 464 human burials from 17 different sites that date from the Bronze Age (2300 to 800 B.C.) to the Industrial Revolution (18th and 19th centuries), and examined parasitic worm eggs in the soil from the pelvises of infected skeletons. In all, 134 of the 464 individuals contained parasitic worm eggs. The highest levels of parasitic infection were found in the remains dating from the Roman and late medieval periods, with the levels being similar to those seen in the worst-affected regions of the world today, the researchers found.
Infections from parasitic roundworms Ascaris and whipworms (Trichuris) were common during the medieval period, the team noted, possibly because of trade, increased urbanization, issues with waste disposal, sanitation or hygiene, and the use of night soil (a euphemism for human excreta) as fertilizer.
In the Industrial Age, worm infection rates differed from site to site, with two of the burial sites having little to no evidence of parasites, while a third, in London, "contained high levels of infection," the researchers wrote in the study. This discrepancy could be due to varying levels of sanitation and hygiene in different regions of the U.K., the team said. After the "Sanitary Revolution" of the Victorian period, improvements in sanitation on a national level meant the level of worm infections reduced on a wider scale.
"The cholera outbreaks between 1831–1866, famously linked to contaminated drinking water by John Snow, were a key driver in sanitary reform (alongside endemic Typhoid) involving infrastructural improvement, legislation and promotion of municipal responsibility," the researchers wrote in the study. "However, many interventions were piecemeal with some areas benefiting earlier than others."
The team behind this research will continue to investigate more infections from the past using their parasite-based approach, including further large-scale explorations of human burials and studies of DNA.
The study was published online April 21 in the journal PLOS Neglected Tropical Diseases.
Originally published on Live Science.
