Murine typhus, caused by Rickettsia typhi and R. felis, is a zoonotic disease transmitted from rodents or, sometimes, other animals, to humans via fleas. It is clinically similar to but milder than epidemic typhus and causes chills, headache, fever, or rash. Diagnosis is with polymerase chain reaction testing (positive in early infection but limited by low sensitivity) and serology (usually negative in early infection); immunohistochemistry of biopsied tissue samples can be a helpful adjunct. Treatment is with doxycycline.
Murine typhus is a zoonotic rickettsial disease. It is also called endemic typhus to differentiate it from epidemic typhus. See Fleas in Dogs and Cats for more information on pathogenesis and transmission in the context of veterinary disease.
Distribution is sporadic but worldwide, with endemic foci in Taiwan, Spain, and Israel. The incidence is low but higher in rat-infested areas, especially in warm, coastal regions (1). In the United States, endemic foci exist in the southern and western areas, particularly Texas, California, and Hawaii (2, 3).
Animal reservoirs include cats, wild opossums, rats, mice, and other rodents. Rat fleas are considered the primary vector, but mouse, cat, and dog fleas do transmit organisms to humans through bites as well (1). Fleas are also natural reservoirs for R. typhi; infected female fleas can transmit organisms to their progeny.
This image shows an Oriental rat flea, Xenopsylla cheopis, which transmits Rickettsia typhi and R. felis, causative agents of murine typhus.
CDC
Murine typhus is not a nationally notifiable condition in the United States (4).
General references
1. Snellgrove AN, Goddard J. Murine typhus: a re-emerging rickettsial zoonotic disease. J Vector Ecol. 2024;50(1):1-13. doi:10.52707/1081-1710-50.1-1
2. Alarcón J, Sanosyan A, Contreras ZA, et al. Fleaborne Typhus-Associated Deaths - Los Angeles County, California, 2022. MMWR Morb Mortal Wkly Rep. 2023 Aug 4;72(31):838-843. doi: 10.15585/mmwr.mm7231a1
3. Ruiz K, Valcin R, Keiser P, Blanton LS. Rise in Murine Typhus in Galveston County, Texas, USA, 2018. Emerg Infect Dis. 2020;26(5):1044-1046. doi:10.3201/eid2605.191505
4. CDC. Information for Public Health Officials. December 11, 2025. Accessed January 5, 2026.
Symptoms and Signs of Murine Typhus
After an incubation period of 7 to 14 days, patients typically present with a nonspecific febrile illness that includes headache, fever with chills, or rashes (1). The fever lasts approximately 14 days without treatment; then temperature gradually returns to normal (2).
This photo shows widespread blistering of the skin due to cat flea bites.
SCIENCE PHOTO LIBRARY
The rash (present in approximately 50% of patients) (2) and other manifestations are similar to those of epidemic typhus but are less severe. The early rash is sparse and discrete. Eschar is absent.
Mortality is lower than in epidemic typhus but is higher in older patients. In one systematic review of murine typhus, mortality occurred in 0.4% of untreated patients (3).
Symptoms and signs references
1. Centers for Disease Control and Prevention (CDC). Clinical Overview of Flea-borne Typhus. April 18, 2025. Accessed January 6, 2026.
2. CDC. Rickettsial Diseases. April 23, 2025. Accessed January 6, 2026.
3. Doppler JF, Newton PN. A systematic review of the untreated mortality of murine typhus. PLoS Negl Trop Dis. 2020;14(9):e0008641. Published 2020 Sep 14. doi:10.1371/journal.pntd.0008641
Diagnosis of Murine Typhus
History and physical examination
Immunohistochemistry
Serologic testing
Molecular diagnostic testing (polymerase chain reaction [PCR]) of a blood sample
For details, see Diagnosis of Rickettsial and Related Infections.
The diagnosis of murine typhus should be suspected when the clinical presentation is consistent with a febrile illness (especially when rash is present) in an endemic area (1). A history of contact with rodents also supports the diagnosis.
Immunohistochemistry (direct immunofluorescence staining) in formalin-fixed tissue samples can detect rickettsial antigens (1).
Serologic testing (indirect immunofluorescence test of serum samples) is considered the preferred diagnostic method; however, this testing is rarely helpful from a management perspective because serial measurements are required and results are often negative in acute illness (1).
PCR testing of whole blood samples can detect rickettsial antigens early in the acute illness, but, because of limited sensitivity, negative results should not deter clinicians from initiating empirical treatment in patients with suspected infection.
Diagnosis references
1. Centers for Disease Control and Prevention (CDC). Clinical Overview of Flea-borne Typhus. April 18, 2025. Accessed January 6, 2026.
2. Civen R, Ngo V. Murine typhus: an unrecognized suburban vectorborne disease. Clin Infect Dis. 2008;46(6):913-918. doi:10.1086/527443.
Treatment of Murine Typhus
Doxycycline
Doxycycline is the first-line treatment of murine typhus. Treatment is commonly empirically initiated and continued until the patient improves, has been afebrile for 72 hours, and has received treatment for at least 7 to 10 days (1).
For patients who cannot tolerate doxycycline, desensitization is recommended.
Although some tetracyclines can cause tooth staining in children < 8 years of age, the United States Centers for Disease Control and Prevention (CDC) advises that a course of doxycycline is warranted (2). Research indicates that short courses of doxycycline (5 to 10 days, as used for rickettsial disease) can be used in children without causing tooth staining or weakening of tooth enamel (2).
For details of treatment, see Treatment of Rickettsial and Related Infections.
Treatment references
1. Centers for Disease Control and Prevention (CDC). Clinical Overview of Flea-borne Typhus. April 18, 2025. Accessed January 6, 2026.
2. CDC. Research: Doxycycline and Tooth Staining. May 15, 2024. Accessed January 2, 2026.
Prevention of Murine Typhus
Murine typhus may be prevented by controlling rat and rat flea populations (1, 2).
No effective vaccine exists.
Prevention references
1. Centers for Disease Control and Prevention (CDC). Preventing Fleas. June 4, 2024. Accessed March 5, 2026.
2. CDC. Controlling Wild Rodent Infestations. April 8, 2024. Accessed March 5, 2026.
Key Points
Murine typhus is transmitted to humans by fleas.
Symptoms begin with fever with chills, headache, or rash; the rash and other manifestations are similar to those of epidemic typhus but are less severe.
Diagnosis is by PCR testing, serology, and immunohistochemistry of biopsied tissue samples.
Treat with doxycycline.
Drug Information for the Topic
