Which of the following pathogens is resistant to normal chlorination of sewage?

Normal chlorination of sewage is primarily effective against a wide range of pathogens, including many bacteria and viruses. However, certain pathogens demonstrate varying degrees of resistance to chlorination processes.

Giardia cysts, for example, are known to be resistant to chlorine and can survive in treated water, making them particularly challenging in wastewater treatment contexts. Similarly, Hepatitis viruses, especially Hepatitis A, can also withstand standard chlorination levels, which poses a risk as they can lead to transmission through inadequately treated sewage. Entamoeba histolytica, the causative agent of amoebic dysentery, presents resistance as well, ensuring its survival through normal chlorination methods.

Given their collective resistance to the conventional chlorination typically used in sewage treatment, it is accurate to state that all of these pathogens are resistant. This understanding underscores the importance of using additional disinfection processes or higher concentrations of chlorine when dealing with wastewater to effectively eliminate these resilient organisms.