Dr Eyrun Kjetland from the School of Biological and Conservation Sciences at the University of KwaZulu-Natal in South Africa presented current research into urogenital schistosomiasis at this year’s ECCMID conference.
Taking a step back to begin with, she said schistosomiasis itself affects 2 billion people worldwide; 80 million of these show symptoms and just over 30 million receive treatment.
It’s a growing problem in some regions, particularly among travelers and migrants. People become infected with schistosomiasis when worm forms of the snail parasite penetrate their skin during contact with infested water. These then live in blood vessels where they grow and reproduce more schistosomes, or eggs. Eggs either pass through as waste or get trapped in the body, causing immune reactions and progressive damage to organs.
Kjetland described the current situation of one target of the schistosomes – the reproductive system. “In the last two decades,” she said, “after the first six community-based studies on this “gyneacological Schistosoma haematobium”, WHO has recommended that this form of the disease should be referred to as urogenital schistosomiasis.”
Below is a summary of key points and issues Kjetland raised during her presentation.
Disease manifestations: bleeding, lesions and infertility
Urogenital schistosomiasis can affect both sexes. In men, the eggs damage the seminal vesicles, prostate and other genital organs. The condition is three times more likely to occur in a female, though, and up to 75% of women in endemic areas are infected. That’s as many as 45 million in rural sub-Saharan Africa alone.
The cervix, Fallopian tubes and vagina are the most common sites to present the eggs. Because of the types of tests available, they are generally only detected once they spread into the cervix. The infection manifests itself in numerous ways, including hormones disturbance if in the ovaries; infertility if found in the Fallopian tubes; and lesions in every area the eggs live.
Lesions and other typical genital changes, such as sandy patches and pathological blood vessels, can make women susceptible to other infections, like HIV. They also make the area so delicate that a mere touch breaks it and sheds blood. This ”contact-bleeding” inevitably makes a sex life very difficult and painful for the female sufferers.
Young sufferers detected late
Also highlighted in the talk was the patient demographic. Although adults are more at risk, urogenital schistosomiasis is expected to affect children too. In most countries, however, the infection remains undetected in children as people assume it is adult-only and the relevant tests are only available later in life.
Girls aged 10-12, i.e. prepubertally, have been found to experience very similar symptoms of genital bleeding, smelly discharge and ulcers. Whether or not these symptoms are a result of schistosomiasis is apparently a mystery because it is only detected when the girls are old enough for the cervical tests.
An interesting thought was added when a particular study showed female sufferers under 20 presented more lesion damage than older older sufferers, raising the issue that catching them early is important.
Treatment is not as simple as some scientists like to think
Chronic schistosomiasis control focuses on reducing disease through periodic, targeted treatment with praziquantel, a drug used for a number of different NTDs. Most studies have found that this drug is effective in treating schistosomiasis with just one dose.
Kjetland noted than praziquantel is only effective in chronic (years) schistosomiasis, not the acute (months) infection. This is because the processes of infection are different and acute infection involves many central processes; so a dose of praziquantel will probably make it worse. The best treatment would be steroids and then praziquantel later on.
According to Kjetland, praziquantel is generally believed to be the “wonder drug” for schistosomiasis, and results which go against this view are sometimes deemed unacceptable. Her research’s initial results into the apparent uselessness of praziquantel and having no significant effect on mucosal bleeding or sandy patch symptoms of urogenital schistosomiasis were not accepted. Kjetland said she had to revisit her “statistician numerous times before her supervisors and publishers” believed her.
This result was thought to be a result of resistance, but retrospective data revealed that history of drug treatment influenced praziquantel effectiveness in urogenital schistosomiasis.
The future of urogenital schisto research
To date, the majority of studies have been small and community-led, so there is still a lot to be done in order to understand and better treat those suffering from urogenital schistosomiasis. Specifically, Kjetland suggested, further research is needed to find more simple low-tech diagnosis systems; better treatment for dangerous lesions; and to explore the preventive effects of mass drug administration.
Recently, we reported on new collaborations to tackle NTDs, and there has been a similar scheme set up for genital schistosomiasis. The current project, which includes joint efforts from Imperial College London and the University of Kwazulu-Natal, will investigate when it is best to treat younger sufferers and develop better diagnostics.