Pasadena Health Department officials are sounding the alarm over 20 confirmed cases of typhus fever so far this year. .

“Typhus fever is a disease that can cause serious complications requiring lengthy hospitalization, and death,” said Dr. Ying-Ying Goh, Pasadena health officer. “All residents should take steps to prevent fleas in and around the home.”

Typhus fever is a disease spread to humans by infected fleas. Typically it is expected that between one and five people will contact it each year in Pasadena. Goh said.

The disease, which is usually contracted in the summer and fall and can be treated with antibiotics, causes fever, chills, headaches and rashes.

City Public Health Director Michael Johnson told the Pasadena Weekly this year’s increase in cases cannot be explained.

“We are seeing increases across Southern California, including Los Angeles, Orange County and Long Beach,” Johnson said.

Locally, feral cats and opossums are known to be carriers of the infected fleas.

Pet dogs and cats that are allowed outside are more likely to come in contact with infected fleas and could spread the disease to humans. Pets and other animals do not get sick from typhus.

Flea-borne typhus, also known as murine or endemic typhus, is a disease carried by fleas infected with the bacteria Rickettsia typhi or Rickettsia felis. There is currently no commercially available vaccine. The disease is not communicable. Treatment is with the antibiotic doxycycline.

According to Goh, the spread of the disease can be curbed locally by not providing food or water for wild animals, keeping garbage containers tightly covered, sealing all openings and crawl spaces under the home, routinely treating pet dogs and cats with flea control and maintaining a yard free of debris by trimming overgrown vegetation that could attract feral cats and opossums.

For more information on preventing typhus, visit the San Gabriel Valley Mosquito and Vector Control District at sgvmosquito.org/flea-borne-typhus.