Question

(a) What are food borne diseases?
(b) Write briefly any two common food borne diseases.

Hint:

To differentiate between bacterial and amoebic foodborne illnesses: bacterial infections (like Salmonellosis) usually have a rapid onset ($12\text{--}24$ hours) and high fever, whereas protozoan infections (like Amoebiasis) have a slower, insidious onset ($2\text{--}4$ weeks) with recurrent bloody stools and less pronounced fever.

Answer 1

Step 1: Definition of Foodborne Diseases (a):
Foodborne diseases (commonly called food poisoning) are illnesses resulting from the consumption of food or beverages contaminated with pathogenic microorganisms (bacteria, viruses, fungi, or parasites), their metabolic toxins, chemical hazards (pesticides, heavy metals), or physical foreign contaminants. These pathogens or toxins infect or irritate the gastrointestinal tract lining, causing acute inflammation.

Step 2: Detailing Two Common Foodborne Diseases (b):

• Salmonellosis (Bacterial Foodborne Infection):
  • Causative Agent: Gram-negative, rod-shaped bacteria belonging to the genus Salmonella (specifically Salmonella enterica).
  • Transmission: Consumption of raw or undercooked poultry, eggs, unpasteurized milk, or water contaminated with animal feces.
  • Pathophysiology & Symptoms: Upon ingestion, the bacteria invade the mucosal cells of the small and large intestines, releasing enterotoxins. This causes acute gastroenteritis, presenting as watery diarrhea, severe abdominal cramps, high-grade fever, nausea, and vomiting within $6\text{ to }72$ hours of ingestion.
• Amoebiasis (Amoebic Dysentery - Parasitic Foodborne Infection):
  • Causative Agent: The protozoan parasite Entamoeba histolytica.
  • Transmission: Fecal-oral route, primarily through the consumption of water or fresh raw vegetables contaminated with mature, infective cysts of the parasite due to poor sewage management or unhygienic food handling.
  • Pathophysiology & Symptoms: In the large intestine, the active trophozoites emerge from the cysts, invade the mucosal lining, and cause characteristic "flask-shaped" ulcers. This presents as amoebic dysentery, characterized by painful abdominal cramps, flatulence, and frequent, semi-solid stools containing blood and mucus (dysentery), often accompanied by low-grade fever.