Which organisms should be considered in a nursery school outbreak of diarrhea?

In a nursery school outbreak of diarrhea, the focus should be on pathogens that are commonly associated with gastrointestinal illnesses in young children. The correct choice includes Giardia lamblia, Dientamoeba fragilis, and Cryptosporidium spp., all of which are significant causes of diarrhea in this age group.

Giardia lamblia is well-known for causing giardiasis, which leads to diarrhea, abdominal cramps, and nausea. It is particularly relevant in settings where children may be in close contact with each other, such as nursery schools, and can spread through contaminated water or surfaces.

Dientamoeba fragilis is another parasite that can cause gastrointestinal symptoms, including diarrhea. It is less frequently diagnosed than Giardia but is still recognized as a contributing factor in outbreaks of diarrhea, especially in children.

Cryptosporidium spp. are protozoan parasites that cause cryptosporidiosis, marked by watery diarrhea. This organism is highly resilient and can spread through contaminated water sources, making it a relevant concern in environments frequented by young children.

The other options contain organisms that are either less likely to be responsible for such outbreaks or are not as commonly associated with diarrhea in children. For instance, Trichomonas vaginalis is primarily a sexually transmitted infection and