Impact of Water Pollution » Infectious Bacterial Diseases from Water

Infectious Bacterial Diseases from Water

Water is essential for life, but when contaminated with harmful bacteria, it can become a serious threat to human health. Waterborne bacterial diseases remain one of the leading causes of illness and death worldwide, particularly in developing countries with limited access to clean water and sanitation.

Key Definitions:

• Waterborne diseases: Illnesses caused by pathogenic microorganisms that are transmitted through contaminated water.
• Bacteria: Single-celled microorganisms that can cause infections in humans when ingested through contaminated water.
• Faecal-oral route: The transmission of bacteria from the faeces of an infected person to the mouth of another person, often through contaminated water.
• Pathogen: A microorganism capable of causing disease.

Major Waterborne Bacterial Diseases

Cholera

Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. It remains a global threat to public health and is an indicator of inequity and lack of social development.

• Symptoms: Severe watery diarrhoea, vomiting and leg cramps. Rapid loss of body fluids leads to dehydration and shock.
• Transmission: Primarily through drinking water or eating food contaminated with the faeces of an infected person.
• Impact: Can cause death within hours if untreated. During severe outbreaks, the case fatality rate may exceed 50%.

Case Study: Haiti Cholera Outbreak (2010)

Following the devastating earthquake in Haiti in 2010, a cholera outbreak began that eventually infected over 820,000 people and killed nearly 10,000. The disease was likely introduced by UN peacekeepers from Nepal, where cholera is endemic. Contaminated waste from their camp leaked into the Artibonite River, a main water source for thousands of Haitians. This case highlights how quickly waterborne diseases can spread in areas with damaged infrastructure and poor sanitation.

Typhoid Fever

Typhoid fever is a bacterial infection caused by Salmonella typhi. It is usually spread through contaminated food or water and is closely linked to poor sanitation and lack of clean drinking water.

• Symptoms: High fever, weakness, stomach pains, headache and loss of appetite. Some patients develop a rash of flat, rose-coloured spots.
• Transmission: The bacteria are passed in the faeces and sometimes urine of infected people. People become infected after consuming food or drink that has been handled by someone who is shedding the bacteria, or by drinking water contaminated with sewage containing the bacteria.
• Impact: If untreated, typhoid fever can be fatal in up to 30% of cases. With prompt treatment, the fatality rate falls to less than 1%.

🌎 Global Distribution

Typhoid affects approximately 11-20 million people annually, causing 128,000-161,000 deaths. It is most common in parts of Asia, Africa and South America where access to clean water is limited.

💧 Water Connection

Typhoid bacteria can survive for weeks in water or dried sewage. Contaminated water sources like wells, rivers and lakes can infect thousands of people in a single outbreak.

🏠 Prevention

Improving water and sanitation infrastructure, treating drinking water and typhoid vaccination programmes are key prevention strategies in endemic areas.

E. coli Infections

Escherichia coli (E. coli) bacteria normally live in the intestines of healthy people and animals. Most varieties are harmless, but some strains, particularly E. coli O157:H7, can cause severe illness through contaminated water.

• Symptoms: Severe stomach cramps, diarrhoea (often bloody) and vomiting. Some infections can lead to haemolytic uremic syndrome (HUS), a serious condition that can cause kidney failure.
• Transmission: Through consumption of contaminated water, undercooked meat, or foods that have been cross-contaminated.
• Impact: While most people recover within 5-7 days, E. coli O157:H7 infections can be life-threatening, especially for young children and the elderly.

Case Study: Walkerton Water Tragedy (2000)

In May 2000, the drinking water supply in Walkerton, Ontario, Canada became contaminated with E. coli O157:H7 and Campylobacter jejuni bacteria. The contamination resulted from farm runoff entering a shallow well after heavy rainfall. Poor water treatment and monitoring practices failed to detect the contamination. The outbreak killed 7 people and made over 2,300 ill in a town of just 5,000 residents. This tragedy led to major reforms in water safety regulations across Canada.

Environmental Factors and Transmission

Prevention and Control Measures

Preventing waterborne bacterial diseases requires a multi-faceted approach targeting different points in the transmission cycle:

Global Impact and Future Challenges

Waterborne bacterial diseases continue to pose significant challenges to global public health:

• Unequal burden: Low and middle-income countries bear the greatest burden of waterborne diseases due to inadequate water and sanitation infrastructure.
• Climate change: Changing climate patterns are altering the distribution and intensity of waterborne disease outbreaks.
• Antibiotic resistance: Many waterborne bacteria are developing resistance to commonly used antibiotics, making infections harder to treat.
• Economic impact: Waterborne diseases cause significant economic losses through healthcare costs, lost productivity and reduced economic development.

Summary

Infectious bacterial diseases transmitted through water remain a significant global health challenge. From cholera to E. coli infections, these diseases cause substantial illness and death, particularly in regions with limited access to clean water and sanitation. Understanding the sources of bacterial contamination, transmission routes and effective prevention strategies is essential for reducing the impact of these diseases.

As we face challenges like climate change, urbanisation and antibiotic resistance, integrated approaches to water management, improved infrastructure and community education will be crucial in preventing waterborne bacterial diseases and ensuring access to safe water for all.