Which organism is the hardest to eliminate effectively from water?

Which organism is the hardest to eliminate effectively from water?

• A. E. coli
• B. Giardia
• C. Cryptosporidiosis
• D. Salmonella

Answer: (C)

Cryptosporidiosis, caused by the parasite Cryptosporidium, is considered particularly challenging to eliminate from water due to its unique characteristics. The organism forms oocysts, which are hardy cysts that can survive in harsh environmental conditions, including chlorine disinfection, for long periods. This resilience makes it more difficult to remove through conventional water treatment processes compared to other pathogens. In addition, Cryptosporidium can be present in relatively low numbers in contaminated water, yet it is highly infectious—requiring only a small number of oocysts to cause infection. This combination of resilience and infectiousness underscores the difficulty of removing Cryptosporidium from water supplies using standard treatment methods typically effective against bacteria or other protozoa. Other organisms, such as E. coli and Salmonella, can typically be eradicated through common disinfection methods like chlorination. Giardia, while also a protozoan that poses a waterborne risk, is generally more susceptible to chlorine or other disinfection processes than Cryptosporidium. Therefore, the unique properties of Cryptosporidium, particularly its resistance to treatment and low infectious dose, establish it as the hardest organism to eliminate effectively from water.

Cryptosporidiosis, caused by the parasite Cryptosporidium, is considered particularly challenging to eliminate from water due to its unique characteristics. The organism forms oocysts, which are hardy cysts that can survive in harsh environmental conditions, including chlorine disinfection, for long periods. This resilience makes it more difficult to remove through conventional water treatment processes compared to other pathogens.

In addition, Cryptosporidium can be present in relatively low numbers in contaminated water, yet it is highly infectious—requiring only a small number of oocysts to cause infection. This combination of resilience and infectiousness underscores the difficulty of removing Cryptosporidium from water supplies using standard treatment methods typically effective against bacteria or other protozoa.

Other organisms, such as E. coli and Salmonella, can typically be eradicated through common disinfection methods like chlorination. Giardia, while also a protozoan that poses a waterborne risk, is generally more susceptible to chlorine or other disinfection processes than Cryptosporidium. Therefore, the unique properties of Cryptosporidium, particularly its resistance to treatment and low infectious dose, establish it as the hardest organism to eliminate effectively from water.