Water borne diseases

Water borne diseases

  • Many water borne disease human pathogens are transmitted by water used for cooking , drinking and swimming.
  • Microbes like bacteria virus and protozoa cause disease.
  • Mostly pathogens transmitted in drinking water.
  • Microbes transmitted in water grow in intestine and leave the body in faeces.
  • From which faecal pollution of water consume the water and pathogen may colonies in intestine to cause disease.
  • So water borne diseases are infectious.
  • Water is infectious even it contain small number of organism.
  • Infection depends on virulence of pathogen and ability of host resistance.

Water borne diseases


  • Caused by Legionella pneumophilia.
  • Thin gram negative road.
  • Complex nutritional requirement with a high iron.
  • Cause respiratory disease.
  • The pathogen usually present at cooling towers evaporative condenser of air conditioner.
  • Grow in water and spread as aerosol in air.
  • Symptoms are headache and fever.
  • Need no treatment to cure resolve in 2-5 days.
  • Sensitive to antibiotics rifampicin and erythromycin.

▶Drinking water disease:-

(1) Cholera:-

  • Caused by vibrio cholerae.
  • Gram negative and curved rod.
  • transmitted through contaminated water.
  • Symptoms are vibrio attached to small intestine epithelial cell and grow to release enterotoxin.
  • Which cause used fluid loss.
  • Treatment with streptomycin or tetracycline shorten the Cholera period with that oral electrolyte solution replacement is the actual treatment.

(2) Giardiasis:-

  • caused by giardia lambia.
  • it is a flagellated protozoans.
  • Transmitted to human by contaminated water.
  • Sometimes it is food borne and sexually transmitted.
  • Symptoms are false smelling nature of diarrhoea and absence of blood or mucus in stool, watery diarrhoea ,intestinal cramps.
  • Treatment can be done by using quinocrine and metronidazole.

(3) Cryptosporidiosis:-

  • Caused by cryptosporidium porvum is a protozoa.
  • This is a intestinal pathogen in dairy cattle.
  • symptoms are severe diarrhoea.
  • In a normal infected person this protozoa is self-limiting.
  • But AIDS patient develop serious complication.
  • For normal person treatment is not required.
  • Cryptosporidium is highly resistant to to chlorine.
  • So only can be removed by sedimentation and filtration.

(4) Amoebiasis:-

  • Caused by protozoan Entamoeba histolytica.
  • Transmitted from contaminated water sometimes through food.
  • Symptoms are sometimes this is symptomatic but the infection continues to lead on certain with diarrhoea and severe intestinal cramps.
  • This is an anaerobic amoeba.
  • Diarrhoea then continues to dysentery with fever.
  • If not treated then it leads to liver, lungs and brain.
  • Can be treated with drug dehydremrtine and dilomanide furoate.

▶Foodborne disease:-

This disease divided into two types:-

(1) Food poisoning on intoxication:

  • Due to consumption of microbial toxin containing food.
  • The microbes liberates exotoxins the food and do not grow inside the host.

(2) Food borne infection:-

  • This is host infection due to pathogen contaminated food.

▶ Food positioning:-

(1) Staphylococcal food poisoning:-

  • Caused by staphylococcus aureus.
  • Release some enterotoxins to food and symptoms absorbed within 1-6 hour.
  • Symptoms are nausea ,vomiting and diarrhoea.

(2) Clostridium perfringens poisoning:-

  • Obligate anaerobe.
  • produce enterotoxin.
  • Symptoms are diarrhoea, intestinal cramp, sometimes nausea and vomiting.

(3) Botulism:-

  • Severe type of food poisoning.
  • Caused by clostridium botulinum.
  • produce exotoxin and aerobic.
  • Toxic can be avoided by heating up to 80 degree Celsius for 10 minutes.

▶Food infection:-

(1) Salmonellosis:-

  • Caused by s typhi .
  • Symptoms are headache ,vomiting diarrhoea and fever.
  • Escherichia coli:-
  • E coli produce enterotoxins.
  • Symptoms are diarrhoea with blood, a kidney failure.
  • Source are uncooked or undercooked meat.

(2) Camphylobactor:-

  • C. Jejuni and c. Fetus
  • gram negative, curved road and microaerobic.
  • Mostly found in children.
  • Symptoms are bloody stool.

(3) Listeriosis:-

  • Caused by listeria monocytogenes.
  • Contaminated through meat dairy products.

(4) Hepatitis:-

  • This is a virus mediated inflammation in liver.
  • Caused by because virus single stranded RNA virus.
  • Transmitted through faecal matters, contaminated water food, milk and cause hepatitis B.
  • Hepatitis b caused by DNA containing hepatitis virus.
  • Transmitted by infected blood, maternal transmission and STD.
  • Third type hepatitis virus in hepatitis C.
  • Cause chronic elements.
  • There are also hepatitis D and E.