Waterborne disease and their causes.

Water is essential for life, yet for many Kenyans, it is also a source of disease and death. In recent times, Kenya has experienced outbreaks of waterborne diseases such as cholera, typhoid, and diarrhea, especially following heavy rains and floods. These outbreaks highlight the close connection between water quality, sanitation, and public health, and they raise serious questions about access to safe drinking water.

Waterborne diseases are caused by microorganisms such as bacteria, viruses, and parasites that contaminate water sources. Cholera, for example, is caused by the bacterium Vibrio cholerae, which spreads through water contaminated with human waste. Typhoid fever is caused by Salmonella typhi, while diarrhea can result from multiple pathogens such as E. coli and rotavirus. These organisms are invisible to the naked eye but can cause severe illness once ingested.

In early 2025, the Kenyan Ministry of Health declared a cholera outbreak during the long rainy season. Cases were reported in Nairobi, Kisumu, Migori and Kwale counties, with more than 250 suspected cases and at least 13 deaths as of May 2025. Health teams carried out rapid response, contact tracing and water sampling to contain the spread.

Scientific studies show that flooding significantly increases the risk of water contamination. When floods occur, latrines overflow, sewage systems break down, and surface water mixes with drinking water sources such as rivers, wells, and boreholes. In informal settlements and rural areas, where sanitation infrastructure is weak, this contamination spreads rapidly. Children, pregnant women, and people with weakened immune systems are the most vulnerable.In Kisii County, health surveillance reported around 128 suspected cases of a probable waterborne illness, with symptoms of diarrhea, fever, and abdominal pain affecting men and women. 

Symptoms of waterborne diseases include severe diarrhea, vomiting, dehydration, fever, and weakness. If not treated promptly, especially in children, these illnesses can be fatal. Medical experts explain that dehydration occurs when the body loses more fluids than it takes in, disrupting essential body functions. Oral rehydration therapy and clean water are often life-saving, yet access remains uneven in many parts of the country.

The science of water treatment shows that simple methods can significantly reduce disease transmission. Boiling water kills most disease-causing organisms. Chlorination and filtration also remove harmful microbes. However, these methods require awareness, resources, and consistent practice. In many communities, lack of information, poverty, and cultural habits limit their effectiveness.

Climate change has worsened the water disease problem in Kenya. Prolonged droughts force communities to rely on unsafe water sources, while sudden heavy rains increase flooding and contamination. Scientists warn that as climate extremes become more common, waterborne disease outbreaks are likely to increase unless strong preventive measures are taken.

Government agencies, health workers, and scientists are working together to respond to outbreaks through surveillance, vaccination campaigns, and public education. However, experts argue that long-term solutions lie in improving water infrastructure, sanitation systems, and hygiene practices. Safe water is not only a health issue but also a scientific and development priority.