Question

Contamination of water with sewage is indicated by cysts of
A. Escherichia
B. Entamoeba
C. Pseudomonas
D. Leishmania

Answer 1

Hint: Sewage can be released into rivers purposefully through pipelines or open defecation, or inadvertently during rainstorms. Cholera, typhoid, and dysentery are all life-threatening human diseases spread by sewage. Schistosomiasis, hepatitis A, intestinal nematode infections, and a variety of other illnesses can all be caused by sewage pollution of water.

Complete solution:
Let us solve this question by analyzing each of the options and their relevance in water contamination in sewage.
Option:A – Escherichia is a genus of coliform bacteria which indicate the fecal contamination of water or contamination of water by sewage but they do not form cysts.
So, Option:A is incorrect.
Option:B – Entamoeba is a genus of protozoans whose cysts in water indicate its contamination by sewage. Infection with Entamoeba histolytica causes amoebiasis in humans which leads to severe diarrhea.
So, Option:B is correct.
Option:C – Pseudomonas is a genus of bacteria and is widely distributed in various environments. It does not form cysts and therefore is not an indicator of contamination of water by sewage.
So, Option:C is incorrect.
Option:D – Leishmania causes Leishmaniasis and spreads through sand fly bites and is therefore not an indicator for contamination of water by sewage.
So, Option:D is incorrect.

Hence option A. Escherichia is the correct answer.

Note:
Entamoeba histolytica is a parasitic protozoan that causes amoebiasis and is a major cause of diarrhoea in poor nations. The parasite's life cycle is divided into two parts: the cyst and the trophozoite. The parasite's infective and non-motile form is called a cyst. It is excreted in faeces and can persist in the environment for weeks. In reality, when sewage systems are poor, E. histolytica is a major source of illness and/or fatality.