By Karen Kirsten Eyram Amoako

Each day, millions of children from developing nations enter rivers, lakes, and streams to swim, fish, or get water for their families. This is just a part of daily life.

However, there is an unseen threat lurking under the surface of water. A tiny worm parasite, released from freshwater snails, can pierce unbroken human skin within minutes and start to travel through one’s bloodstream for years to come.

This worm causes schistosomiasis, otherwise known as bilharzia – the most common neglected tropical disease. It infects over 240 million people in the world, with an additional 700 million at risk of contracting it. Sub-Saharan Africa experiences the biggest burden of the disease.

Disease of Poverty
Schistosomiasis is a disease of poverty, lack of sanitation and availability of clean water sources, which is preventable but still exists. The parasite has a complicated lifecycle. Eggs excreted by humans through urine or feces hatch in water, releasing larvae which infect certain snail species. The snails release second-stage larvae/cercariae, which infect humans through the skin while they are in water.

The adult worms reside in the blood vessels surrounding the bladder or the intestines. The females lay between several hundred to several thousand eggs each day. Some eggs are expelled out of the body where they repeat the process. Other eggs become lodged in organs leading to long-term inflammation and serious damage.

Devastating Consequences of Schistosomiasis
There are two types of the disease:

Urogenital schistosomiasis (S. haematobium) which causes bloody urine, pain during urination, fibrosis of the bladder, damage to the kidneys and increased chances of developing bladder cancer. Genital lesions can lead to infertility and increased susceptibility to HIV infection.

Intestinal schistosomiasis (S. mansoni, S. japonicum) which causes abdominal pain, diarrhea, enlargement of the liver and the spleen and portal hypertension. Severe cases are complicated by life-threatening bleeding due to rupture of esophageal varices.

Children are at high risk of infection. The consequences are anemia, stunted growth, learning difficulties and poor academic performance.

An Easy Cure
The best news about schistosomiasis is that it can be effectively cured. One dose of Praziquantel—an oral drug that is safe even for children, pregnant women and nursing mothers—is able to cure more than 90% of cases.

According to WHO, there should be Mass Drug Administration (MDA) in endemic areas whereby the entire community is treated annually or biennially. In the year 2022 alone, more than 50 million people have been treated.

However, treatment alone is not enough because reinfection takes place very quickly without prevention.

Breaking the Cycle
To ensure schistosomiasis elimination, various measures have to be put in place:

Mass Drug Administration, which is the routine treatment to reduce infection prevalence.

Health Education by informing the community on ways of avoiding contact with contaminated water and proper hygiene practices.

Sanitation by providing latrines to avoid environmental contamination.

Providing clean and safe water supply.

Snail Control through the destruction of the intermediate host either through environmental manipulation or mollusciciding.

The Global Objective
WHO’s Roadmap on NTDs 2021-2030 seeks to eliminate schistosomiasis as a public health problem in all endemic countries by 2030.

Great progress has been made. A number of countries in the Americas, Middle East, and Asia have succeeded in eliminating transmission. Mass MDA campaigns in Africa have managed to lower infection rates significantly.

However, there still exist a number of problems including reinfection, limited resources, poor health care systems and emergence of drug resistance.

The Way Forward
Schistosomiasis is a preventable and curable disease. We have the means to get rid of it; what we require is commitment, funding, and community involvement.

Think of a world where kids can play freely in rivers, where women do not put their health at risk while fetching water from streams, where communities live happily, free from preventable diseases.

This dream can become a reality. The silent killer in the water can be stopped, and that can only happen if we all join hands to achieve this goal.