Waterborne Illness: Understanding Diseases From Water Pollution

Water pollution is a pressing issue that has severe implications for human health. It is caused by both human and natural factors, such as urbanization, population growth, industrial production, and climate change. Pollutants in water include chemicals, waste, plastic, and other harmful substances, which can lead to water contamination and, consequently, the spread of diseases. These diseases can be waterborne, caused by pathogens such as viruses, bacteria, and protozoa, or they can arise from toxins produced by harmful algae and cyanobacteria. The quality of drinking water is essential for public health, and poor water quality has been linked to various illnesses, including diarrhoea, cholera, dysentery, hepatitis, typhoid, polio, and even cancer. Inadequate water treatment and sanitation services expose individuals to preventable health risks, especially in healthcare facilities and developing countries.

Diarrhoea and cholera

Diarrhoea is the most widely known disease linked to contaminated water. According to the 2021 World Water Development Report by UNESCO, about 829,000 people die each year from diarrhoea caused by unsafe drinking water, sanitation, and poor hand hygiene. This includes nearly 300,000 children under the age of five, representing 5.3% of all deaths in this age group. Diarrhoea is characterised by abdominal pains, fever, nausea, and headaches, and can cause premature death in vulnerable individuals.

Waterborne diarrhoea is caused by contaminated water supplies, which can be a result of human activities such as improper disposal of solid waste, sand, and gravel, or natural factors like high salinity and sodium levels. Diarrhoea can also be caused by eating raw or undercooked produce, including fruits, vegetables, and seafood, that have been contaminated by cholera bacteria.

Cholera is a bacterial disease that can cause severe diarrhoea and dehydration, and even lead to death if left untreated. It is usually spread through contaminated water and food, with the bacterium Vibrio cholerae found in sources such as surface or well water, seafood, and grains. Cholera outbreaks are more likely to occur in areas without access to clean water or adequate sanitation, and can be particularly severe in crowded living conditions.

The main symptom of cholera is watery diarrhoea, which can be mild or severe and is often accompanied by vomiting. This can lead to a rapid loss of fluids and electrolytes, causing dehydration, which can be life-threatening. However, most people exposed to the cholera bacterium do not become ill and may not even know they have been infected. They can still pass the bacteria in their stool, contributing to the contamination of water sources and the spread of the disease.

To prevent and treat cholera, access to clean drinking water and sanitation facilities is crucial. Drinking sanitised water, washing hands with soap and clean water, and getting vaccinated are effective measures to reduce the risk of cholera infection. If infected, it is essential to seek medical attention, stay hydrated by drinking water, broth, or oral rehydration solutions, and avoid anti-diarrheal medications that can worsen symptoms.

Hepatitis and encephalitis

Water pollution is caused by both human and natural factors. Human activities such as urbanization, population growth, industrial production, and improper disposal of solid waste directly affect water quality. On the other hand, natural factors like the natural environment and human activities contribute to water pollution.

Waterborne diseases are closely associated with unsafe water, inadequate sanitation, poor personal hygiene, and oral-anal sexual activity. Diarrhoea is the most well-known disease linked to contaminated water. However, unsafe drinking water can lead to over 50 kinds of diseases, including skin issues, malnutrition, and even cancer.

Hepatitis

The hepatitis A virus (HAV) is one of the most common causes of acute viral hepatitis globally. It is present in all regions, regardless of the country's economic level, and is closely associated with insufficient sanitation and limited access to clean water. The virus is transmitted primarily through the faecal-oral route, where an uninfected person consumes food or water contaminated with the faeces of an infected person. In families, this can occur through dirty hands when an infected person prepares food. While hepatitis A is usually associated with sewage-contaminated or inadequately treated water, waterborne outbreaks are infrequent.

The hepatitis A virus can also be transmitted through close physical contact with an infected person, although casual contact does not spread the virus. The incubation period is typically 14–28 days, and symptoms can range from mild to severe, including fever, malaise, loss of appetite, diarrhoea, nausea, abdominal discomfort, dark-coloured urine, and jaundice. In rare cases, hepatitis A can lead to acute liver failure, which is often fatal.

Encephalitis

Encephalitis is a rare and serious condition that causes inflammation and swelling of the brain. It can be caused by viral infections, insect bites, or an autoimmune reaction that affects the brain. Viral encephalitis is the most common form, and arboviruses spread by mosquitos, fleas, and ticks can lead to encephalitis. Bacterial and fungal encephalitis, caused by infections, are less common forms of the condition. Autoimmune encephalitis occurs when the immune system mistakenly attacks the brain, causing inflammation and affecting brain function.

The symptoms of encephalitis vary depending on the type and cause. Viral encephalitis symptoms develop quickly and include early warning signs such as drowsiness, high fever, loss of consciousness, nausea, and vomiting. Autoimmune encephalitis symptoms develop more slowly and include neurological issues like memory problems, noticeable personality changes, speech difficulties, and weakness or loss of movement in some body parts. Both infective and autoimmune encephalitis can be life-threatening and require immediate medical attention.

Typhoid and polio

Water pollution is a pressing issue that poses significant health risks to human populations, particularly in developing and under-resourced regions. Among the various diseases caused by water pollution, Typhoid and Polio are two of the most concerning.

Typhoid

Typhoid fever, caused by the bacterium Salmonella Typhi, is a life-threatening infection that can lead to severe illness and even death. It is usually spread through contaminated food or water sources. Once ingested, the Salmonella Typhi bacteria multiply and enter the bloodstream, causing symptoms such as high fever, fatigue, headache, nausea, abdominal pain, and gastrointestinal issues. Typhoid fever is a significant public health problem, particularly in regions with inadequate sanitation and limited access to safe drinking water. According to estimates, there are approximately 9 million cases of typhoid fever annually, resulting in about 110,000 deaths worldwide each year. The risk of typhoid is higher among children and in areas with poor sanitation and unsafe water supplies.

The impact of water pollution on the transmission of typhoid has been observed in various parts of the world. For example, in Kathmandu, Nepal, typhoid outbreaks have been linked to contamination of the water supply. Similarly, in Blantyre, Malawi, studies have identified risk factors associated with pediatric typhoid fever, highlighting the importance of safe water access and sanitation.

Polio

Poliomyelitis, commonly known as polio, is another disease that has been associated with water pollution. While the role of drinking water as a source of polio infection was initially disputed, recent evidence suggests that drinking water can indeed be a primary vector for the poliovirus. This is particularly relevant in densely populated areas where water scarcity and the recycling of wastewater are common. As population growth continues to strain water resources, the potential for water-borne polio transmission increases, requiring a re-evaluation of eradication campaigns.

Preventative Measures

To prevent the spread of waterborne diseases like typhoid and polio, it is crucial to prioritize safe water supply and adequate sanitation. This includes improving access to clean drinking water, ensuring proper wastewater treatment, and promoting good hygiene practices, such as frequent handwashing with soap. Additionally, vaccination plays a vital role in protecting against both typhoid and polio. The development and distribution of effective vaccines, such as the typhoid conjugate vaccine, are essential steps toward reducing the impact of these diseases, especially in high-risk areas.

Schistosomiasis

Water pollution is linked to the transmission of various diseases, including cholera, dysentery, typhoid, and polio. One such disease, schistosomiasis, is caused by parasitic worms contracted through exposure to infested water. It is a significant health concern, with an estimated 700 million people at risk and 251.4 million requiring preventive treatment in 2021.

The disease is prevalent in tropical and subtropical areas, particularly in disadvantaged communities without access to safe drinking water and adequate sanitation. In 2021, the COVID-19 pandemic disrupted interventions and treatment for schistosomiasis, highlighting the ongoing challenges in managing this disease.

The World Health Organization (WHO) and other health authorities have recommended control measures such as periodic, large-scale administration of the antischistosomal drug praziquantel, especially to high-risk groups like school-aged children. However, a comprehensive approach that includes improved water quality, sanitation, and snail control is also necessary to effectively reduce transmission and protect vulnerable populations from this waterborne disease.

Cancer

Water pollution is a serious issue that affects billions of people worldwide, including millions in the United States. It arises from both human and natural factors, such as urbanization, population growth, industrial production, and climate change. The impact of water pollution on human health is significant, with unsafe drinking water and poor sanitation being the leading cause of about 90% of deaths from diarrhoeal diseases, which claim the lives of over two million people annually.

One of the most concerning health consequences of water pollution is its potential link to cancer. While the specific mechanisms and risks associated with water pollution and cancer are still being studied, current research suggests several ways in which water pollution may contribute to cancer development.

One of the well-known carcinogens found in water is arsenic. Arsenic is a naturally occurring substance that can contaminate water sources. Ingesting high levels of arsenic is a known cause of bladder cancer, and there is also a dose-response relationship between cumulative arsenic exposure and bladder cancer risk. However, the risk associated with lower levels of arsenic exposure is less certain, and larger population studies are needed to make definitive conclusions.

In addition to arsenic, disinfection byproducts (DBPs) formed during the water treatment process are also of concern. When chlorine, used to disinfect water, interacts with organic material in the water, it can create DBPs. These by-products have been associated with an increased risk of bladder and rectal cancer. Studies have found a link between long-term exposure to high levels of DBPs in drinking water and elevated risks of rectal and bladder cancer.

Another contaminant that has come under scrutiny recently is per-and polyfluoroalkyl substances (PFAS), also known as "forever chemicals." PFAS can enter water sources through industrial wastewater, contaminated landfills, or contaminated soil on farmland. While research is still ongoing, initial studies suggest a possible link between PFAS exposure and an increased risk of testicular and kidney cancer.

It is worth noting that the impact of water pollution on cancer risk may vary depending on the specific context and the types of contaminants present. For example, the fluoridation of water has been scrutinized but is currently believed to pose little to no cancer risk. Additionally, the use of chlorine for water treatment, while potentially contributing to cancer risk through DBPs, also plays a crucial role in reducing the risk of infectious diseases.

In conclusion, water pollution is a pressing global issue that has severe implications for human health, including an increased risk of cancer. While further research is needed to fully understand the complex relationship between water pollution and cancer, it is clear that efforts to improve water quality and reduce exposure to contaminants are essential to mitigate potential health risks.

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