Which disease would be least likely associated with poor sanitation and transmission by fecally contaminated water or food?

Which disease would be least likely associated with poor sanitation and transmission by fecally contaminated water or food?

• A. Amebiasis
• B. Filariasis
• C. Ascariasis
• D. Giardiasis

Answer: (B)

The key idea is how these parasites are transmitted. Diseases that spread through the fecal-oral route are tightly linked to sanitation, because people become infected by ingesting cysts or eggs that contaminate water, food, or hands. Amebiasis, giardiasis, and ascariasis all fit that pattern. Amebiasis comes from Entamoeba histolytica cysts in contaminated water or food; giardiasis from Giardia lamblia cysts in contaminated water; ascariasis from ingesting Ascaris eggs that contaminate soil and produce or hands. In settings with poor sanitation, exposure to these infectious forms is common. Filariasis, on the other hand, is not transmitted by ingestion of contaminated water or food. It is spread by mosquito vectors; microfilariae circulate in the blood and are picked up by biting mosquitoes, which then transmit larvae to a new person. While sanitation can influence mosquito breeding environments, the transmission route itself is vector-based rather than fecal-oral. So, the disease least likely to be associated with poor sanitation and transmission by fecally contaminated water or food is filariasis.

The key idea is how these parasites are transmitted. Diseases that spread through the fecal-oral route are tightly linked to sanitation, because people become infected by ingesting cysts or eggs that contaminate water, food, or hands.

Amebiasis, giardiasis, and ascariasis all fit that pattern. Amebiasis comes from Entamoeba histolytica cysts in contaminated water or food; giardiasis from Giardia lamblia cysts in contaminated water; ascariasis from ingesting Ascaris eggs that contaminate soil and produce or hands. In settings with poor sanitation, exposure to these infectious forms is common.

Filariasis, on the other hand, is not transmitted by ingestion of contaminated water or food. It is spread by mosquito vectors; microfilariae circulate in the blood and are picked up by biting mosquitoes, which then transmit larvae to a new person. While sanitation can influence mosquito breeding environments, the transmission route itself is vector-based rather than fecal-oral.

So, the disease least likely to be associated with poor sanitation and transmission by fecally contaminated water or food is filariasis.