Why China-Zanzibar partnership helps control Schistosomiasis

ZANZIBAR: ZANZIBAR’S efforts to eliminate schistosomiasis have received a major boost following the successful completion of a comprehensive snail survey across Pemba Island by a joint team of Chinese and Tanzanian experts.

The work undertaken by the ‘Second Experts Team of the China-Zanzibar Schistosomiasis Control Cooperation Project’ and marks a critical step toward evidence-based control and elimination of the disease in the Islands.

On July 18, 2025, the team completed a large-scale island-wide survey targeting Bulinus snails—the intermediate hosts of Schistosoma haematobium, the parasite responsible for urogenital schistosomiasis.

According to the World Health Organisation (WHO), Schistosomiasis, also known as bilharzia, snail fever, bilharzia, and Katayama fever is a neglected tropical disease- a parasitic disease caused by flatworms called schistosomes.

It’s a major health problem, particularly in tropical and subtropical regions, and is contracted through contact with contaminated freshwater. While often asymptomatic initially, it can lead to chronic illness and organ damage if left untreated.

The disease prevalent in Africa, parts of South America, the Caribbean, the Middle East, and Asia, at first, there are often no symptoms of schistosomiasis but within one to two months of infection, symptoms may develop including fever, abdominal pain (liver/ spleen area), bloody diarrhoea or blood in the stools or urine, coughing, malaise, headaches, rashes and body aches.

According to project leader Dr Dai Yang, the survey spanned more than 300 key water bodies and covered over 15 million square meters. “Bulinus snails are a critical link in the transmission of schistosomiasis,” said Dr Yang. “Controlling their presence in water bodies is essential to interrupting the disease cycle locally.”

Despite severe challenges posed by this year’s unusually long rainy season, the Chinese expert team, working closely with staff from the Neglected Tropical Disease Control (NTDC) Office in Pemba, maintained strict adherence to schedule and achieved full survey coverage.

Dr Chen Xiaojun, another member of the expert team, said the Chinese scientists played a hands-on role in every stage of the project, from planning and field supervision to data quality control and analysis. “We also prioritised technical training and capacity building to empower local teams with long-term skills,” he noted.

The joint team had to contend with major logistical and environmental hurdles. Persistent rainfall rendered many roads impassable and made snail collection in water bodies significantly more difficult. Some vehicles got stuck in deep mud, forcing teams to travel on foot and manually transport equipment.

To adapt, the team employed flexible work plans that prioritised survey areas with improved weather. They also coordinated field operations closely and enhanced transportation support. Field teams showed exceptional dedication, often hiking long distances and working under harsh conditions to complete the job.

“This was not just about collecting data,” said Dr Yang. “It was a demonstration of commitment, resilience, and international cooperation.”

The survey revealed that out of the 300+ water bodies examined, 130 contained Bulinus snails. More than 10 of these tested positive for schistosome larvae. These findings offer critical baseline data for Zanzibar’s health authorities and provide a scientific foundation for targeted snail control and health education campaigns, especially in high-risk communities.

“This information is invaluable for our intervention strategies,” said Dr Khamis Seif Khamis, a local health officer involved in the project. “Our continued collaboration with Chinese experts is helping us not only respond effectively but also build our own long-term capacity in disease control.”

The project reflects the growing strength of China-Zanzibar cooperation in public health, particularly in the fight against neglected tropical diseases. Under the guidance of the Chinese team, local personnel gained hands-on experience and were trained to conduct complex operations independently in future rounds of surveillance and control.

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The success of this first-round 2025 snail survey marks a key milestone in the broader mission to eliminate schistosomiasis from Zanzibar. It also exemplifies what can be achieved through international collaboration grounded in science, mutual respect and shared public health goals.

With precise data now in hand and strong local ownership of the project, the stage is set for the next phase, targeted snail control and health interventions aimed at reducing habitats and breaking the transmission cycle once and for all.