Which of the following diseases is a risk for animal care workers as well as expectant mothers handling domestic cat litter?

Toxoplasmosis is a parasitic disease caused by the organism Toxoplasma gondii, which is commonly found in the feces of infected cats. Animal care workers and expectant mothers are at particular risk for this disease primarily due to the potential for exposure to contaminated cat litter.

For animal care workers, handling cat litter or interacting with cats that may be shedding the parasite poses an occupational health risk. For expectant mothers, avoiding exposure to Toxoplasma is especially crucial because infection during pregnancy can lead to serious complications for the developing fetus, including congenital disabilities or miscarriage.

In contrast, the other diseases listed, while they may pose risks to certain populations or in specific contexts, do not have the same direct link to handling cat litter or exposure to domestic cats. Human parvovirus, rubella, and hepatitis B are not transmitted via cat feces and hence are not considered relevant risks in the context of handling cat litter. This makes toxoplasmosis the correct choice for this specific scenario.