Washington, Apr 15 (IANS): Scientists have identified specific strains of the Toxoplasma gondii parasite, which may account for premature births and severe birth defects in the US.

Pregnant women can become infected with T. gondii through contact with infected cat faeces or by eating undercooked meat. Such women may miscarry, give birth prematurely, or have babies with eye or brain damage.

Researchers used a new blood test developed by National Institute of Allergy and Infectious Diseases (NIAID), to pinpoint T. gondii strains that children acquire from their acutely infected mothers while in the womb.

Over half of the world's human population is estimated to carry a Toxoplasma infection. During the first few weeks post-exposure, the infection typically causes a mild flu-like illness or no illness, according to a university statement.

Thereafter, the parasite rarely causes any symptoms in otherwise healthy adults. However, those with a weakened immune system, such as AIDS patients or pregnant women, may become seriously ill, and it can occasionally be fatal.

"If undetected or untreated, congenital toxoplasmosis can have serious consequences for a child's quality of life," noted NIAID director Anthony S. Fauci. "The findings from this study support the value of screening for toxoplasmosis to identify patients who could benefit from treatment," he added.

The experimental test developed by Michael Grigg from NIAID's Lab of Parasitic Diseases and his colleagues improves upon the older tests because it can detect the presence of strain-specific antibodies that distinguish infecting strains from one another.

The test was applied to blood samples collected between 1981 and 2009 as part of the National Collaborative Chicago-Based Congenital Toxoplasmosis Study.