Health officials see 6 listeriosis cases in a month
By LEIGH HOPPER
Houston Chronicle
Epidemiologists are investigating an upsurge in listeriosis cases:
ï What: An infection caused by listeria monocytogenes, a rod-shaped bacterium.
ï Source: Raw vegetables, meat and unpasteurized dairy products, including queso fresco.
ï At risk: Pregnant women, newborns and people with weakened immune systems.
ï Symptoms: Fever, muscle aches and diarrhea.
Houston is facing a possible outbreak of a serious bacterial illness that can result in miscarriages and babies born with life-threatening infections, a city health official says.
The Houston Department of Health and Human Services has detected an upsurge this month of listeriosis, a disease linked with consumption of contaminated ready-to-eat meats, unpasteurized dairy products, and a soft Mexican-style cheese called queso fresco.

The Health Department identified six listeria cases this month, all among Hispanics. They include three pregnant women, two newborns and an elderly woman. All were hospitalized, but recovered, officials said.
“We (usually) see about eight cases a year. So six cases within a month is certainly an upsurge,” said Porfirio Villarreal, Health Department spokesman. “It’s very elevated. That’s why we would do the investigation.”
Villarreal said the Health Department reserves “outbreak” status for clusters of disease that occur in higher-than-expected numbers and have a single source. Earlier this summer, three more cases were reported. There have been no deaths.
Epidemiologists are still investigating to see what the cases might have in common, Villarreal said. The women live in different parts of Harris County and have histories of eating different foods.
In addition, the city is doing lab work to determine whether the germs in the cases are identical organisms, or are made up of genetically different strains.
The bacterium Listeria monocytogenes , found in soil and water, causes the illness. Bacteria can contaminate foods of animal origin such as meats and dairy, and raw vegetables.
Earlier this year, the U.S. Food and Drug Administration issued an alert to consumers cautioning them that eating queso fresco made from raw milk, or produced improperly, puts them at risk of serious diseases caused by food-borne bacteria.
Federal officials are working closely with officials in Texas and other states with large Hispanic communities to step up enforcement against the smuggling of queso fresco from Mexico and its illegal sale in the United States.
In North Carolina this year and last, 12 Hispanics were infected with listeriosis after eating the cheese, including 11 pregnant women.
These infections resulted in five stillbirths, three premature deliveries and two infected newborns.
Pregnant women, newborns and people with weakened immune systems because of AIDS, cancer, diabetes and kidney disease are most at risk for becoming ill. Severe infections can cause meningitis, coma and internal abscesses.
The infection is treated with antibiotics, but the death rate is 30 to 50 percent in infected newborns.
Symptoms of listeriosis include fever, muscle aches and diarrhea. If infection spreads to the nervous system, symptoms may also include headache, stiff neck, confusion, loss of balance or convulsions.
The Health Department warns against eating unpasteurized dairy products and recommends people cook leftover foods or ready-to-eat-foods, such as hot dogs, until steaming hot. People should thoroughly wash vegetables before eating them.
The Centers for Disease Control and Prevention estimates that every year in the United States 2,500 people become seriously ill with listeriosis and 500 die.
leigh.hopper@chron.com