Foodborne Infection May Be a Family Affair

Toxoplasmosis in households and families explored in study of US infections

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) Even with infections that don't spread easily, family members might still run the risk of developing the same infections, simply due to a shared environment. Researchers explored this issue for one infection in particular — toxoplasmosis.

The parasite Toxoplasma usually causes very few problems, but it can be a serious issue for people with immune conditions and pregnant women.

The study authors looked at 32 households of people with Toxoplasma infections and found that in over half of the cases, another family member developed the infection as well.

"Be sure to cook meat and poultry to the correct temperatures."

According to the Centers for Disease Control and Prevention (CDC), the parasite Toxoplasma gondii and the resulting infection (toxoplasmosis) is the third leading cause of foodborne illness-related death in the US.

"More than 60 million men, women, and children in the US carry the Toxoplasma parasite, but very few have symptoms because the immune system usually keeps the parasite from causing illness," explained CDC. However, the parasite can cause severe illness and death in pregnant women and in people with weakened immune systems.

The infection can be spread by eating contaminated food, food that touched contaminated surfaces, drinking contaminated water, contact with contaminated soil or feces, or between pregnant mothers and unborn children, CDC reported.

The researchers behind the new study, led by Despina G. Contopoulos-Ioannidis, MD, of the Stanford University School of Medicine in Stanford, California, wanted to explore how the infection might spread among families with an infected person in the household.

"When a case of acute toxoplasmosis is identified in a family, additional household members might have been infected around the same time period; family members frequently share common exposures to food or environmental sources potentially contaminated with Toxoplasma gondii," the study authors explained. "Identification of additional infections could lead to earlier implementation of appropriate interventions for persons in certain high-risk groups, such as immunocompromised persons and pregnant women."

The researchers used data from the Palo Alto Medical Foundation Toxoplasma Serology Laboratory in California during the years 1991 to 2010. From this data, the researchers focused on 32 families of people with acute toxoplasmosis that had one or more additional family member who was tested for the infection.

Out of this group of 32 families, 18 (56 percent) had one or more additional family member with an acute or recently acquired infection.

The study authors noted that the sample size was small, and that out of the 889 acute infections they looked at, only 32 of the index patients had household members who were tested for toxoplasmosis. More research is needed to confirm these findings among a larger population.

However, the study authors concluded "When a case of acute toxoplasmosis is diagnosed, screening of additional family members should be considered, especially if pregnant women or immunocompromised patients live in those households, so that appropriate preventive strategies and/or therapeutic interventions are applied."

The study will be published in the December issue of CDC's Emerging Infectious Diseases journal. No conflicts of interest were reported. 

Review Date: 
November 12, 2013
Last Updated:
November 25, 2013