Food and Water are essential for the survival of biological entities. Life can’t exist without food and water. Apart from the significance of food and water for life, these can act as a major source of various bacterial, viral, and parasitic diseases if contaminated.

By Sahar Younis,Dr Muhammad Sohail Sajid

Water and food-borne diseases are conditions that occur due to the intake of water containing diseases causing agents such as any parasite, virus, bacteria, fungus, etc. that may cause disorder, illness, disability, and even death. Humans and animals can get these diseases while washing, bathing, drinking contaminated water, or by eating food that is exposed to contaminated water. This is amongst major issues, especially in the developing world. Diarrhea and vomiting are the most common reported symptoms of water and food-borne illness, but these symptoms can extend to eye, skin, and respiratory problems. Among food and water-borne diseases, illness induced by parasites is of global focus and is a forefront topic of research. Parasites can be single-cell tiny organisms to the worm that can be seen with the naked eye that can be present in food and water. These parasites can be transmitted from one individual to another, by consuming contaminated food or water or by touching the feces of the infected individual.

About 72 species of parasites (protozoa and helminths) can reach humans and cause a severe form of illness, mostly spread from animals to humans. The life cycle of most of the parasites presents a complex picture as some require more than one host to complete their life cycle. Illness caused by these parasites can range from mild discomfort to possible death. Some common parasites contaminating food and water include Taenia solium, Taenia saginata, Toxoplasma gondii, Cryptosporidium parvum, Giardia duodenalis, Trichinella spiralis, and Cyclospora cayetanensis. Twenty species of tapeworms and five species of protozoa (class of parasites) can enter the human body through the consumption of raw/ sea of freshwater food. These water and food-borne parasitic infections are associated with old food habits, poverty, and low sanitation. Other related factors include food supply globalization, higher rate of international travel, change in habits, and increasing disease-prone population. However few detection and diagnostic methods are available to detect this disease-causing parasite. Water and food-borne parasites that contaminate food and water including Giardia, Cryptosporidium, Entamoeba histolytica, Fasciola, toxoplasma, Cyclospora cayetansis, and Acanthamoeba spp are of public health concern. The possible contamination of food and water can threaten the lives of millions of people specifically in the underdeveloped world. Humans can get the infection by drinking water contaminated with sewage. Secondary to sanitary facilities and availability of clean water other factors that can contribute to the increased number of food and water-borne parasitic infections include malnourished children, old age people, and people having weak immune systems due to chronic infection like HIV. Increased intake of raw, undercooked food from open markets and street food vendors where food safety is doubt-full, has played a significant role to deteriorate public health and increase the possibility of transmission of parasites.

Cryptosporidiosis is a common disease found in humans and animals leading to diarrhea, one of the frequently reported diseases due to contamination of water. According to WHO, it is one of the most common parasitic diseases. The fate of infection is determined by the immune status and age of the individual. In the same way, giardiasis is also one of the parasitic infections that usually infect the intestine of humans. It is estimated that 280 million of human infections caused by Giardia are reported. Entamoeba is another protozoan parasite causing significant illness in the population. Giardia, cryptosporidium, Entamoeba and Cyclospora widespread contaminate water bodies, freshwater, and tap water. Infection caused by Toxoplasma can lead to congenital abnormalities, stillbirth, and miscarriage in pregnant women. Food and water-borne diseases emerge when potential hazards remain unidentified. These infections primarily infect the stomach and intestine.

Common symptoms include

  • Vomiting
  • Diarrhea
  • Fever
  • Cramps
  • Nausea
  • Abdominal cramps
  • Dehydration
  • Weight loss
  • Loss of appetite
  • Bloating
  • Fatigue
  • Muscle aches

Prevention and control

Prevention relies on food safety and ensuring the consumption of clean water and hygiene.

  • Fruits and vegetables should be clean
  • Make sure to drink clean and treated water
  • Pay attention to the community water system
  • Water should be tested frequently to keep an eye on the presence of any pathogen
  • Ensure personal hygiene and sanitation
  • Avoid undercooked meat
  • Boil the water for at least one minute to kill the eggs of parasites, wherever you are not sure about safe water
  • Make sure to wash, peel properly and cook raw vegetables before consuming them
  • Avoid swimming in public swimming pools and don’t swallow water while swimming
  • The infected person must wash hands frequently to minimize the spread of infection
  • Routine practice to wash hands using warm water and soap for at least 20 sec can help to eradicate foodborne illness
  • Cook the food to a safe temperature and refrigerate, handle the food leftover food carefully and refrigerate.
  • Make sure to clean the meat grinders, whenever you grind meat
  • In case of any severe illness consult to the doctor.


Sahar Younis

DVM, M. Phil parasitology

University Of Agriculture Faisalabad

Dr Muhammad Sohail Sajid

Associate professor, Department of parasitology

University Of Agriculture Faisalabad