Toxoplasma gondii infects the brain, as do many otherpathogens. However, Toxoplasma differs from otherpathogens in that it _. Select one: a. causes destruction of brain tissue b. causes tumor formation in the brain c. manifests in behavioral changes in the host d. always kills the host
The correct answer and explanation is:
The correct answer is: c. manifests in behavioral changes in the host
Toxoplasma gondii is a protozoan parasite that infects many warm-blooded animals, including humans. While many pathogens infect the brain and cause damage such as tissue destruction or tumors, Toxoplasma gondii is unique because it can alter the behavior of its host. This behavioral manipulation is particularly well-studied in rodents. Infected rodents exhibit reduced fear of predators, such as cats, which increases the likelihood that the parasite will complete its life cycle inside the cat’s intestines, its definitive host.
Unlike pathogens that cause direct damage to brain tissue, Toxoplasma gondii often forms cysts in the brain without causing overt destruction. These cysts can remain dormant for long periods. In humans, the infection is usually asymptomatic in healthy individuals, but it can cause neurological problems in immunocompromised people or in fetuses when a pregnant woman is infected. The subtle behavioral changes in humans are an area of ongoing research, with some studies suggesting links between Toxoplasma infection and changes in personality, risk-taking behavior, or certain psychiatric disorders, though these findings are still debated.
The parasite does not cause tumor formation in the brain nor does it always kill the host. Instead, it can persist in the brain chronically with minimal symptoms, making its ability to influence host behavior a distinctive feature. This phenomenon highlights a fascinating example of how some parasites have evolved mechanisms to manipulate host biology to enhance their own survival and transmission, which sets Toxoplasma gondii apart from many other brain-infecting pathogens.