Tropical syphilis, a dangerous bacterial infection, is found not only in humans, but also in other primates, an international group of experts working with monkeys from central Africa has found out. This means that to eradicate the disease by 2020, as planned by the World Health Organization, can be more difficult than it was thought. The study is published in the journal Emerging Microbes & Infections .
Tropical syphilis, or yaws, causes the spirochaete Treponema pallidum pertenue, a related subspecies of the causative agent of syphilis Treponema pallidum pallidum. This is a bacterial infection of the skin, bones and joints, which is transmitted by contact with secretions from the foci of the skin. If left untreated, yaws can lead to disability and even death. Now the causative agent is found in at least 14 countries and is a danger primarily for children who infect each other in games. In the 1950s, when tropical syphilis was affectedabout 50 million people, the WHO began a campaign of mass treatment of penicillin infection, and the number of cases fell sharply. However, then attention to the disease weakened, and now, according to the organization, about 2.5 million people are infected.
“For a long time it was believed that the bacterium that causes tropical syphilis only infects people, but our new study confirms that this is not the case,” said co-author Verena Schuenemann of the University of Tübingen, cited by the press services of the institutes that conducted study.
The group took samples of skin and skin secretions from smoky mangobes, green monkeys and Dogerian baboons in Tanzania, Gambia, Senegal and Cote d’Ivoire. The scientists note that all the monkeys had pronounced symptoms of the disease in the form of ulcers on the genitals, muzzle and limbs. Analysis of the genome of the pathogen showed that it is the same spirochete Treponema pallidum pertenue, which causes yaws in humans: in some cases, the genomes coincided by 99.989 percent.
The authors of the study hope that it will help clarify the evolutionary history of the disease and find out how often people get it from other primates. Judging by the fact that in countries where they managed to detect monkeys infected with tropical syphilis, cases among people have not been registered for several decades, most likely, this happens rarely, the article says. They also emphasize that WHO should continue to work to eradicate tropical syphilis, but their findings show that infection monitoring, even in countries where it has been spread among humans, has to be strengthened.
Signs of another disease, believed to be characteristic only of people – Alzheimer’s disease – were found in chimpanzees in 2017 : in the brains of the deceased aged chimpanzees, beta-amyloid plaques and neurofibrillary tangles consisting of tau protein were found.