i. Typhoid
• It is caused by pathogenic bacterium Salmonella typhi.
• It is spread by contaminated food and water.
• It generally enters the small intestine and then migrates to other organs through blood.
• Typhoid fever can be confirmed by Widal test.
• Mary Mallon, called Typhoid Mary, was a cook and a typhoid carrier who continued to spread the disease for several years through the food prepared by her, before it was discovered.
Symptoms
a. Constant high fever (39°C to 40°C)
b. Weakness
c. Stomach pain
d. Loss of appetite
e. Constipation
f. Headache
g. Intestinal perforation and death may occur in severe cases.
ii. Amoebic dysentery (Amoebiasis)
• It is caused by an intestinal endoparasite, Entamoeba histolytica, found in large intestine of humans.
• Housefly acts as mechanical carrier and transmits the parasite from faeces of infected person to the food.
• Infection takes place through contaminated food and water.
Symptoms
a. Abdominal pain
b. Constipation
c. Cramps
d. Stool with excess mucous and blood clots.
iii. Filariasis/Elephantiasis
• It is caused by filarial worms, Wuchereria bancrofti and Wuchereria malayi.
• Female Culex mosquito is the vector.
Symptoms
a. Inflammation of organs in which they live
b. Blockage of lymph vessels of lower limbs resulting in swelling. Lower limbs appear like legs of elephant, thus the name.
c. Genital organs may also be affected, leading to deformation.