Water plays an important and fundamental role in human civilization and progress because it is necessary to drink, prepare food, bathe, irrigate crops, plant, and many other purposes. Unfortunately, about two and a half billion people do not have access to clean drinking water.
According to the World Health Organization, more than 5 million people die every year from contaminated water. 50% of these deaths are from intestinal bacterial diseases, cholera being the main cause of death. Children under five years of age are most affected by water-borne bacterial diseases (about 4.1% of global pathogen infections). Raw water can contain many contaminants that it reaches through sewage and factory waste. But many pathogenic and infectious organisms may arise from the water itself.
Numerous diseases that spread across water, be they bacterial, viral, fungal or protozoan, have made officials and researchers interested in studying water microbiology in order to constantly improve and purify water. We have already talked about bacterial diseases that are transmitted by contaminated water. In this article, we will discuss viral diseases, their nature and their implications for human health.
For viruses to survive in water, they need the right temperature, the right light (ultraviolet rays have an adverse effect on the virus), pH and salinity,
aside from organic matter and matter suspended in water.
Hepatitis A: is caused by the HAV virus, which is transmitted to humans through water contaminated with human faeces. Symptoms include itchiness and jaundice. The death rate for hepatitis is approximately 1% of people infected.
Polio: is caused by poliovirus, more than 90% of infected people are asymptomatic, 4 to 8% are exposed to poliovirus disease, 1-2% are sensitive to meningitis, 1% are paralysed, primarily children or young adults. The virus invades nerve cells and enters the central nervous system, causing tumours and muscular paralysis. The deaths are due to the virus infecting the muscles which control the respiratory system.
SARS (Severe Acute Respiratory Syndrome): SARS viruses are spread by contaminated water and treated inappropriately. Symptoms include fever, cough, sore throat, bowel problems, muscle pain, intestinal tiredness and lethargy. The Coxsackievirus is transmitted through water contaminated with some secretions from people infected with the virus itself. This virus is classified in categories A and B.
Type A affects the skin and mucosa, has an incubation period of one to two days, and the symptoms appear as sore throats, tiredness, malaise and loss of appetite, herpetic angina, meningitis, ocular haemorrhage, and HFMD (hand, foot and mouth) which appear as small ulcerated blisters on the soles of the feet, hand, and mouth and wingspan for 10 days, leaving little scars. Children are most at risk from infection.
Type B affects the heart, pancreas and liver, resulting in inflammation of the heart muscle and liver. Symptoms are fever, abdominal pain, pulmonary problems and headache for 12 days. The complications are pericarditis and finally encephalitis. In 2007, several children were infected with the Coxsackie virus in eastern China, 22 children died and a further 800 were infected, including approximately 200 children admitted to treatment.