Abstract

Toxoplasma gondii is an opportunistic parasite that can cause severe disorders in infants and pregnant women and can also be lethal in immunologically compromised individuals. During unfit host immune conditions, and as a consequence to latent stage opportunity, the protozoan stimulates serious infection, and signifies higher morbidity and mortality including humans with Acquired Immuno-Deficiency Syndrome (AIDS) or those receiving corticosteroids and cancer chemotherapy. Tamoxifen drug (TAM) is a selective estrogen receptor modulator (SERM), which is commonly used for treatment of breast cancer; it has a known immunomodulatory effects on the patient, especially if administered for a long time as happens in cases of post breast cancer surgery and anti-recurrence prophylactic measures where women might persist to take TAM for years. The research question here was: Can TAM reactivates latent toxoplasmosis? To assess the possible stressful effect of TAM, rats were experimentally infected by T. gondii (RH strain). Three months later, they were treated by oral administration of TAM (10 mg/kg body weight/day) for 7, 14, 21 and 28 days. Tamoxifen effect on toxoplasmosis dynamics was estimated by counting Toxoplasma brain cysts and serological detection of anti-parasitic IgM and IgG all through the experiment time. The results showed an initial  insignificant decrease in parasitic burden in groups treated for one week followed by a significant increase in groups treated for 14, 21 and 28 days. There was also  a significant decrease in IgM titers  in groups treated for one  and two weeks while there was a significant increase in IgM titers in groups treated for three and four weeks. There was a significant increase in IgG titrers in groups treated for 14 and 21 days and a border line significant increase in the 1st week while there was non-significant increase in 4th week.

Key words: Toxoplasmosis, tamoxifen, breast cancer, serological, Toxoplasma brain cysts, immunomodulatory.