Los Angeles County Department of Public Health released its latest report earlier this month, revealing a record high number of cases of flea-borne typhus in the county last year. The confirmed cases reached 220, with 90% of patients requiring hospitalization.
According to the Centers for Disease Control and Prevention (CDC) in the United States, fleas infected with typhus can cause wounds on the skin when they bite humans or animals. When fleas feed on blood, they excrete feces containing bacteria that can enter through the bite wound or other wounds, or even enter the body through breathing or rubbing eyes, leading to infection.
Typhus transmitted by fleas is a notifiable disease in California. Over the past three years, cases of typhus caused by fleas in Los Angeles County have been steadily increasing, from 124 cases in 2023, 187 cases in 2024, to 220 cases in 2025. In 2010, there were only 31 cases of this disease reported.
The Public Health Department of Los Angeles County stated that severe cases of typhus have been reported throughout the county. Last year, there were three localized outbreaks, occurring in downtown Los Angeles, Santa Monica, and the unincorporated area of Willowbrook between South Los Angeles and Long Beach.
Regionally, the United States reports the highest number of typhus cases in Southern California, Hawaii, and southern Texas. In some parts of South America, Central America, and Africa, cases of this disease are quite common.
In terms of seasonal patterns, these cases occur throughout the year, often peaking in late summer and early fall.
Symptoms caused by flea bites are generally mild and may include fever, headache, muscle pain, nausea or vomiting, cough, rash, etc., typically appearing within two weeks after being bitten. However, they can also develop into severe typhus requiring hospitalization.
Although rare, a few deaths have been reported due to typhus, including three cases in Los Angeles County in 2022.
According to a CDC report published in August 2023, a few severe cases of typhus can lead to myocarditis, septic shock with disseminated intravascular coagulation, and hemophagocytic lymphohistiocytosis (HLH). HLH, although rare, progresses rapidly and typical symptoms include fever, low blood cell counts, enlarged liver and spleen, abnormal clotting or liver function, among others. If not diagnosed early and treated promptly, it can be life-threatening.
The Public Health Department of Los Angeles County reported that the main animals infected by fleas in the area include rats, stray cats, and opossums. People who come into contact with these animals are at risk of contracting typhus spread by fleas. Additionally, pets like cats and dogs that go outdoors may also come into contact with fleas carrying the infection.
These animals do not suffer from the disease themselves but can transmit it to humans. Typhus does not spread among humans.
Dr. Muntu Davis, a health official in Los Angeles County, stated in a press release that the number of such cases has reached a historic high, with most requiring hospitalization. Therefore, taking some simple preventive measures is crucial, such as regularly using flea control products on pets, avoiding contact with stray animals, and preventing wild animals from nesting in or around homes.
1. Protect yourself and your pets. Keep pets indoors as much as possible; when outdoors, use EPA-registered insect repellents that specify they can prevent fleas.
2. Avoid attracting wild or stray animals. Do not leave pet food outside and do not feed or touch free-roaming animals.
3. Maintain a clean yard, store garbage in sealed containers, and close off animal entryways or sources of food around the house.
4. If stray animals, rodents, or opossums are found near the house, report it promptly to the local animal control department.
5. Familiarize yourself with the symptoms of typhus. If you experience symptoms such as fever, chills, headache, rash, etc., seek medical attention immediately.