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How can snails be more deadly to women than crocodiles?

23 September 2020



The answer is female genital schistosomiasis, a neglected tropical disease which causes immeasurable suffering for millions of women and girls in Africa.

When Bill Gates published a chart of the deadliest animals in 2014, there were the usual suspects: sharks — which are almost universally feared — were bottom of the list. Crocodiles ranked 10th. Mosquitoes — a tiny insect — were top. But there was also surprise at the animal that was seventh on the list: freshwater snails. How could a snail be more deadly than sharks, wolves, lions and crocodiles?

The answer is schistosomiasis — also known as bilharzia — a neglected tropical disease, which causes immeasurable suffering for millions of women and girls in Africa. 229 million people, across 52 countries, are at risk of schistosomiasis, a potentially fatal disease that develops when people come into contact with water contaminated by certain snails that carry parasites. These parasites penetrate through a person’s skin and move through the body. The disease causes chronic ill-health and can lead to health issues later in life such as scarring of the liver, bladder cancer or kidney failure.

Female genital schistosomiasis

Schistosomiasis has another, lesser known, effect: female genital schistosomiasis (FGS). FGS is caused by an inflammatory reaction to the schistosome eggs trapped in body tissue, which causes fibrosis and scarring of the female genital tract.

FGS causes immeasurable suffering to women in sub-Saharan Africa. Early signs of the disease are a burning sensation in the genitals, spot bleeding, bloody discharge, stress incontinence and lower abdominal pain. The disease can rapidly progress into swellings or ulcerations of the vulva and vagina, causing genital bleeding and pain.
Symptoms develop toward reproductive organ damage, leading to infertility, ectopic pregnancies, miscarriage, premature birth and/or low birth weight. The disease is often misdiagnosed — with symptoms confused with those of sexually transmitted infections or cervical cancer — and the subsequent mismanagement of FGS can have profound physiological and psychological impacts on women and girls.

And the symptoms are not just physical: The effects on fertility have serious consequences for a woman’s relationships with her family and community, often resulting in marginalisation, stigma, isolation and the threat of violence.

Crucially, there is evidence to suggest links between FGS and HIV. In sub-Saharan Africa, AIDS-related conditions are the second leading cause of death for adolescent girls and young women, who are 44% more likely to acquire HIV than men. Studies in Mozambique, Tanzania and Zimbabwe have shown that adult women with FGS are three to four times more likely to be living with HIV; and adolescent girls with FGS have a higher proportion of HIV receptors than those without FGS.

As well as links with HIV/AIDs, there is strong epidemiologic overlap between FGS and cervical cancer. FGS has been suggested as a possible cofactor in the development of precancerous lesions and cervical cancer.

But one of the most shocking facts about FGS is the sheer number of women affected: 56 million women in sub-Saharan Africa alone.

In spite of all this, FGS remains largely neglected. It has never been reviewed or assessed by the Global Burden of Disease Study. It is not mentioned in most medical textbooks (or in the media) and this means low awareness, frequent misdiagnosis and little recognition from national bodies and policy makers.

An integrated approach to intersecting health challenges for women in sub-Saharan Africa

The majority of women and girls in sub-Saharan Africa are at risk of the combination of cervical cancer, FGS and HIV. Due to this overlapping burden, a new World Health Organization (WHO) paper argues that programmes aimed at diagnosing, preventing and/or treating these health conditions should be integrated.

Preventive interventions for cervical cancer, HIV and FGS can all be successfully delivered through existing programmes and doing so would strengthen health systems in the areas where those diseases are prevalent, which is key for achieving universal health coverage (UHC).

But what would an integrated approach look like?

Firstly, the availability of the drug praziquantel — a drug which prevents schistosomiasis — is key. Women who have been treated with praziquantel at least once before they are 20 are 50% less likely to develop FGS later in life.

Praziquantel is currently delivered to school children during large scale drug delivery programmes but is not otherwise available within the primary health care system. Because many women and girls do not attend schools, they often miss out on this crucial preventive treatment. An integrated response to cervical cancer, FGS and HIV would boost praziquantel treatment for girls and women beyond primary school drug distributions.

Secondly is the issue of accurately diagnosing FGS. The WHO’s new paper argues that FGS can be diagnosed during screening procedures for cervical cancer. The WHO has even published a guide to help health care professionals recognise and diagnose FGS. The guide also suggests FGS should be included in guidelines and training modules for the management of sexually transmitted infections and encourages parallel screening for HIV, sexually transmitted infections and cervical cancer.

Meanwhile, a study in Zambia is evaluating genital self-swabbing as a potential low-cost approach to community-based diagnosis for FGS.

The third aspect of an integrated approach is advocacy. The WHO and Joint United Nations Programme on HIV/AIDs (UNAIDS) developed a joint advocacy brief in 2019. The document aims to increase knowledge and awareness of FGS among policymakers and affected communities, while encouraging programmatic integration in areas endemic for urogenital schistosomiasis.

Integrated approaches like the one described in the new WHO paper — which have a strong approach based on the right to healthcare and which join up multiple public health programmes — create new opportunities and expand upon existing ways to reach more girls and women.

Dirk Engels, Senior Adviser at Uniting to Combat NTDs and co-author of the new paper, said: “An integrated approach offers an opportunity to combine disease-specific initiatives. This gives us a chance to strengthen health systems at all levels and provide comprehensive and better-quality services to those most in need, all while addressing the intersecting health, sociocultural and economic issues facing women and girls.”

You can read more about schistosomiasis and female genital schistosomiasis here.

You can read the new WHO paper — Integration of prevention and control measures female genital schistosomiasis, HIV and cervical cancer — here.

This article was originally published on Medium.com