Updated at 9 p.m.

Hidalgo County health professionals confirmed mumps cases at Mission and PSJA school district campuses Wednesday, contributing to an ongoing outbreak that now numbers 46 cases countywide.

This is a part of the “second wave” of cases with a third anticipated, Hidalgo County Health and Human Services Director Eduardo “Eddie” Olivarez said. Mission CISD sent a letter to parents Wednesday to take caution and be aware of the virus. The district also took measures to call parents and stakeholders Tuesday evening. The Mission campus where the mumps case was confirmed is Bryan Elementary School.

“The campus has been thoroughly disinfected in addition to the regular scheduled cleaning,” the letter stated. “We will continue to work closely with Hidalgo County health officials on any other precautionary steps that may be necessary.”

Sick students should not attend school and infected persons should limit contact with others, according to the letter.

Mission school district spokesperson Craig Verley said the individual could not be named or identified as a faculty, student or staff at this time. He said the school is undergoing normal operations.

Olivarez said the PSJA ISD case was reported last week at PSJA Memorial Early College High School.

The original mumps outbreak occurred at the University of Texas Rio Grande Valley, with reports confirming a student testing positive early last month or late March. This outbreak is believed to be connected with two Mission gyms and parts of McAllen, Edinburg and Pharr. A mumps case also occurred within the Weslaco school district in late April.

Last week, the county confirmed 39 cases and has since confirmed an additional seven.

High-contact “school-type” and “team” settings are often where viruses like mumps spread, Olivarez said.

Easter may also have contributed to the increase in confirmed cases, with large family gatherings and people traveling in and out of the Valley, as there are also mumps cases throughout Texas and other states.

The college semester recently ended for many institutions leading to students moving either back to the Valley or away, he said, which may lead to a “third wave.”

However, predicting the amount of cases is too difficult due to the factors surrounding the outbreak, he said, because it takes 14-24 days for a person to display symptoms after being exposed to the virus.

Mumps is highly contagious and causes the salivary glands to swell up, along with symptoms of a fever and headache, according to the MCSID letter. It is spread through contact with saliva and respiratory drops from the mouth and throat.

Measles, mumps and rubella, or the MMR vaccine, is recommended as a preventive measure and anyone who suspects having the virus should visit a physician and limit contact with others. Basic hygiene, such as covering your mouth when coughing and washing hands thoroughly are all ways to help prevent the spread.