What can pets contract from ingesting contaminated soil or water?

The correct answer is Giardia, as this protozoan parasite is commonly transmitted through ingestion of contaminated water or soil. Giardia is often found in environments where fecal contamination occurs, such as areas frequented by wildlife or other infected animals. When pets consume contaminated water or soil, they can ingest the cysts of Giardia, which can lead to gastrointestinal illness characterized by diarrhea, weight loss, and vomiting.

Understanding the transmission pathways for Giardia is essential in preventing infection in pets. The parasite's lifecycle includes a cyst stage that can survive outside a host in the environment, making it more resilient than some other parasites. Regular monitoring of water sources and maintaining hygiene in pet areas can reduce the risk of Giardia infection.

Other options describe different types of parasites or infections with unique transmission routes. For instance, heartworm is transmitted through mosquito bites rather than through contaminated water or soil. Toxoplasmosis is primarily associated with ingestion of oocysts from cat feces or contaminated food, and fleas are ectoparasites that infest the skin and fur of animals directly rather than being ingested from soil or water.