Signaling System of Parasites Identified

Scientists presented a potential key to better drugs to fight toxoplasmosis parasite hoping to find new drugs for toxoplasmosis and other parasites that now can evade treatments by turning dormant in the body.

Their findings help explain how the parasite that causes toxoplasmosis transforms into a cyst form that resists drugs and the body's immune system, yet can emerge from its dormant state to strike when a patient's immune system is weakened.

The research team found a cellular signaling system that takes hold when the parasite is stressed, enabling it to transform into the cyst surrounded by a protective barrier. The identified signaling system could serve as a target to block the transformation into the cyst form or to attack the parasite while in the cyst form.

The Toxoplasma gondii parasite converts from an active state to the inactive cyst state when it is stressed, for example, by heat from fever. Medications to treat Toxoplasma gondii are effective but too toxic for extended use, and they do not affect the cyst form, so the scientists.

The discovery linking this stress-response mechanism to cyst formation and maintenance offers a possible target for new drugs, but could also lead to a preventative vaccine for animals.

The Toxoplasma gondii parasite can infect most animals and birds, but it reproduces in cats, which can shed the parasite in their feces. Humans can be infected through contact with the infected feces or litter. People can also become infected by consuming undercooked meat.

Most infected people show flu-like symptoms or no symptoms at all. However, the scientists state, for people with immune system problems – such as those undergoing chemotherapy or people with AIDS – the disease can cause serious effects including lung problems, blurred vision and seizures. Also, infants born to mothers who are infected during or shortly before pregnancy are at risk for severe complications, miscarriages or stillbirths.

MEDICA.de; Source: Indiana University