Which parasite is most likely causing symptoms in a transplant patient on steroids, originally from Central America?

The correct answer is Strongyloides stercoralis, which is significant due to its association with immunocompromised states, such as in transplant patients who are on steroid therapy. Steroids suppress the immune system, allowing opportunistic pathogens like Strongyloides to cause infections that might remain asymptomatic in immunocompetent individuals.

In Central America, the prevalence of Strongyloides is notable, and individuals traveling from or residing in endemic areas are at increased risk for exposure. This nematode can remain in a dormant state within the host and can reactivate when the immune system is compromised, leading to severe symptoms. Symptoms can range from gastrointestinal issues to more severe forms of disseminated disease in those with weakened immunity.

The other parasites listed do not align as closely with the risk factors present in this scenario. For instance, Trypanosome brucei rhodesiense, while a concern in certain regions, primarily causes sleeping sickness and is more related to insect vectors. Giardia lamblia is a protozoan that generally causes gastrointestinal symptoms but tends to infect immunocompetent individuals rather than those on immunosuppressive therapy. Schistosoma japonicum is typically associated with chronic infections and not directly linked with acute complications in immun