Basics of waterborne diseases - Dangers for humans and animals
Water-borne diseases are any illness caused by drinking water contaminated by human or animal feces,containing pathogenic microorganisms.Over the past decades,the picture of water-related human health issues has become increasingly complex, with the rise of new water-related infectious diseases and the re-emergence of ones already known.such as salmonellosis,cholera shigellosis, malaria, schistosomiasis or modern infections such legionellosis or SARs.There is still lots of work to be done to protect human health worldwide.
DIMENSION OF THE PROBLEM
In third world countries four-fifths of all the illnesses are caused by water-borne diseases,with diarrhea being the leading cause of childhood death.The global picture of water and health has a strong local dimension with the following:
Source 'Progress on drinking water, Sanitation and Hygiene 2017', section 1
WHO 2017
WHO (world Health Organization) estimates show that worldwide over 2 billion people are infected with Schistosoma and soil transmitted helminthes and 300 millions of these suffer serious illness as a result.
Diarrhea occurs globally and causes 4% of all deaths and 5% of the health loss to disability.
In Bangladesh alone, some 35 million people are exposed, on a daily basis, to elevated levels of arsenic in their drinking water which ill eventually threaten their health and shorten their life span.
After the Tsunami attack in Asia on Sunday the 26th of December 2004 people faced the threat of water borne diseases linked to flooding like Shigellosis, Cholera, Hepatitis A,Leptospirosis, Typhoid Fever,Malaria and Dengue fever.
TRANSMISSION
Water borne diseases spread by contamination of drinking water systems with the urine and feces of infected animal or people.
This occurs where public and private drinking water systems get their water from surface waters (rain, creeks, rivers lakes etc ), which may be contaminated by infected animals or people. Runoff from landfills, septic fields, sewer pipes,residential or industrial developments can also sometimes contaminate surface water.
This has been the cause of many outbreaks of fecal-oral diseases such as cholera and typhoid.Still there are many other ways in which fecal material can reach the mouth, for instance on the hands or on contaminated food.
The germs in the feces can cause the diseases by even slight contact and transfer, which may occur due to floodwaters, water runoff from landfills septic fields, and sewer pipes.The picture below shows the fecal-oral routes of diseases transmission.
The only way to prevent transmission is to improve the peoples hygienic behavior and to provide them with certain basic needs: drinking water washing and bathing facilities and sanitation.Malaria transmission usually happens when large numbers of people sleep outdoors during hot weather or sleep in houses that have no protection against invading mosquitoes.Malaria mosquitoes, tropical black flies, and bilharzias snails can all be controlled with efficient drainage because they all depend on water to complete their life cycles.
PREVENTION
Clean water is a pre-requisite for lowering the spread of water-borne diseases. t is acknowledged that the prevalence of water-borne diseases can be greatly reduced by provision of clean drinking water and safe disposal of faeces .Water is decontaminated to il any pathogens that may be present in the water supply and to prevent them from growing again in the distribution systems. Disinfection is then used to avoid the growth of pathogenic organisms and to protect public health and the choice of the disinfect relies upon the individual water quality and water suppl system.without it,the risk from waterborne disease will increase.The two most common methods to kill microorganisms in the water supply are: oxidation with chemicals such as chlorine, chlorine dioxide or ozone, and irradiation with Ultra-violet (UV) radiation.