Some areas require heavy equipment to clear mosquito breeding sites. Photo credit: National Malaria Control Programme02 December 2024, Sana’a, Yemen – In early August, heavy rains caused torrential floods across many regions of Yemen, severely damaging infrastructure and inundating streets and homes.

Poor sanitation has heightened the risk of waterborne diseases. Stagnant water from the floods created breeding sites for mosquitoes, increasing the risk of malaria and dengue fever outbreaks, while reduced access to clean water led people to store available supplies in containers inside their homes, creating additional sites for vector breeding.

Yemen is among 6 countries in the Eastern Mediterranean region with areas of high malaria transmission and accounts for the majority of malaria cases in the Arabian Peninsula. The World Malaria Report estimates that more than 21 million people in Yemen are at risk of malaria. Dengue fever, which overlaps with malaria in endemic areas, is also a major public health problem.

Since the beginning of 2024, Yemen has reported 1 051 287 suspected malaria cases and 13 739 suspected cases of dengue fever. Climatic, geographic and socioeconomic factors make the western coastal areas particularly susceptible and recent weather fluctuations, including rains, have contributed to the spread of vector-borne diseases, endangering vulnerable communities.

Supported by European Civil Protection and Humanitarian Aid Operations (ECHO), the World Health Organization (WHO) collaborated with the Yemeni Ministry of Public Health and Population and the National Malaria Control Programme to conduct a larval spraying campaign from 19 to 24 September.

Together with local authorities and community members, 40 teams participated in the campaign, benefiting over 4 million people in the governorates of Al-Mahwit, Amran, Hajja, Hodeidah and Sana’a. Areas that contain mosquito breeding sites, including swamps, ponds, the banks of valleys, open reservoirs and pits, were prioritized for intervention. 

An initial survey identified 4664 villages and valleys for possible intervention out of which 1160 areas were confirmed as positive breeding environments. The Hodeidah governorate had the highest concentration, accounting for 48% of all targeted areas.

Management of a mosquito breeding site using an insect growth regulator in Tehama region. Photo credit: National Malaria Control ProgrammeOf the positive mosquito breeding sites, 58% were natural and 42% per cent human-made. The proportion of human-made sites increases annually, often due to the building of water barriers and the draining of valley water for commercial sand extraction. 

The campaign also identified mosquito breeding sites in flood-affected areas which were then controlled by permanent removal and drainage or managed through the use of insect growth inhibitors. Permanent breeding sites were subjected to continuous monitoring and sectoral coordination strengthened through community initiatives and collaboration with relevant local authorities.

“Participatory action, involving local communities and various sectors, is crucial in controlling outbreaks. This campaign exemplified successful collaboration, with local authorities and community initiatives playing a key role in the planning and execution, covering a wide geographical area,” said WHO Representative and Head of Mission to Yemen Dr Arturo Pesigan.

“Continued cooperation with local authorities and community members is essential to foster their role in controlling breeding sources and preventing new ones, protecting communities and leaving no one behind.”

The ongoing conflict in Yemen has severely impacted communities across the country, exacerbating humanitarian crises and health challenges. The health care system in Yemen, which has one of the highest disease prevalence rates globally, is overwhelmed, and poverty and harsh living conditions further endanger the health and well-being of millions of people.

Controlling whooping cough in Amad village, Anss district, Dhamar Governorate

2 December 2024  – In July 2024, an Electronic Integrated Disease Early Warning System (eIDEWS) coordinator in Dhamar Governorate noticed an increase in suspected whooping cough cases, with 5 reported in Amad village. An RRT was dispatched to investigate and conducted house-to-house visits. Within a week the team had reported 65 suspected cases, mostly children under 5. Alarmingly, all of those affected were unvaccinated, a result of either parental lack of awareness or vaccine refusal.

The RRT responded by isolating cases to prevent further spread. Treatment and prophylaxis of cases and close contacts was provided, together with community education and awareness-raising, including engagement with local community leaders. The RRT continued monitoring the area for 3 weeks, during which no new cases emerged.

Responding to an acute watery diarrhoea outbreak in Amran and Dhamar governorates

In May 2024, there was a spike in suspected cholera cases in Amran Governorate, with 23 cases reported within 1 week. In July 2024, Dhamar Governorate also experienced a significant increase in suspected cases, particularly in Khabaj village, located in the Mayfa'at Anss district.

The eIDEWS coordinator noticed the alarming trend. RRTs were deployed to both locations to investigate. They confirmed that all cases met the standard cholera definition. Contact tracing and house to-house visits found no new infections. The team distributed medical supplies to affected families, providing treatments and chlorinated water to 6 households in Dhamar and 40 households in Amran.

The RRTs engaged with the local imam and community leaders to promote the importance of hygiene and handwashing, and conducted health awareness sessions, reaching 100 community members in Dhamar and 40 in Amran. The sessions focused on cholera prevention and hygiene practices. After 3 weeks no new cases had been reported.

Preventing and treating acute watery diarrhoea in Abyan Governorate

In June 2024, Muhannaf General Hospital in Lawder district requested support after an alarming increase in its acute watery diarrhoea caseload. The number of cases had reached 767, and there had been 6 deaths.

Access to water in Lawdar district is restricted and the district capital, the city of Lawdar, depends on tankers for drinking water.

An RRT was deployed to help monitor cases, intervene in treatment, engage with medical and nursing staff and organize awareness raising sessions. Training sessions were also provided to health workers who interacted with cases.

Preventive and therapeutic support provided by the team included 45 awareness sessions, held in both the hospital and in households, which reached 224 contacts. The RRT also visited 52 houses, distributing flyers and pamphlets on cholera prevention, and spoke with an additional 98 contacts.

The RRT’s actions led to a decrease in incidence and improvement in the hospital’s monitoring and recording of cases, and helped build the capacity and motivation of hospital staff.

Continued investment in Yemen's health surveillance infrastructure is vital for sustainable recovery and resilience against future health crises.

Learn more about how WHO and the World Bank are strengthening disease surveillance in Yemen

1 December 2024, Aden and Sana’a, Yemen – Yemen’s enduring crisis has created one of the world’s most disease-vulnerable environments, with persistent outbreaks of cholera, measles and dengue.

In collaboration with the World Bank – via the International Development Association and the Pandemic Fund – WHO provides support to help Yemen detect and respond to the constant barrage of infectious disease threats.

“Disease outbreaks pose severe risks to Yemen’s most vulnerable populations, particularly children and the displaced, straining public health and social cohesion,” says WHO Representative to Yemen Dr Arturo Pesigan.

Since 2017, WHO has facilitated the operation of Yemen’s Electronic Integrated Disease Early Warning System (eIDEWS). The system now has almost 2400 sentinel surveillance sites, designated locations across Yemen where consistent health data collection allows disease trends to be mapped. Each day, more than 270 alerts are generated through the system, most of them via heath facilities reporting cases of infectious diseases presenting for care.

The system is complemented by 333 rapid response teams (RRTs) across Yemen. Composed of health workers who can deploy within 24 hours, RRTs investigate alerts, contact trace and provide treatment and/or supportive supervision and health education to communities. RRTs deploy multiple times a week, playing a crucial role in detecting and containing outbreaks.

WHO is helping build future generations of disease detectives by supporting the Field Epidemiology Training Programme (FETP). FETP has been operating in Yemen since 2011. In 2024, the intermediate course graduated 15 new field epidemiologists who will go on to serve in 7 governorates across Yemen.

WHO will continue to provide support to strengthen Yemen’s surveillance and response capabilities in line with the International Health Regulations. The Pandemic Preparedness and Response Project (PPRP), funded by the Pandemic Fund and with financing from the Emergency Human Capital Project (EHCP) in partnership with the World Bank, is key to delivering this support.

Learn more about the activities of eIDEWS coordinators and RRTs