KATY, Texas -- Several students at a Katy elementary school have been diagnosed with an illness that causes diarrhea, KPRC Local 2 reported Tuesday.

Harris County Public Health and Environmental Services officials said the students, who attend Golbow Elementary in the Katy Independent School District, have shigellosis.

Shigellosis is an illness caused by bacteria. Symptoms of shigellosis include diarrhea -- sometimes with blood or mucous -- fever, stomach cramps and vomiting.

The illness normally resolves itself within about a week but can last longer.

Shigellosis is very infectious and is easily spread by infected children when their hands become contaminated with feces.

Officials said it is possible the illness will show up at other schools because it is spread so easily.

Thorough hand washing is the most effective way to control the spread of the illness, officials said.

Officials said that because shigellosis is passed from person to person so easily, it is important that anyone infected be excluded until free of diarrhea and fever for at least 24 hours, without the use of medication.

Several cases can quickly lead to an outbreak, officials said.

In rare cases, shigellosis can cause serious illness and require hospitalization.

Letters were sent home to parents to help them prevent their child from being infected.

For more information, contact the HCPHES at 713-439-6000.