From the Guidelines
Murine typhus is an infectious disease caused by the bacteria Rickettsia typhi, primarily transmitted to humans through the bites of infected fleas, with rodents being the main reservoir. The disease is characterized by symptoms such as fever, headache, body aches, and sometimes a rash that begins on the trunk and spreads to the extremities, typically appearing 1-2 weeks after exposure 1.
Key Characteristics of Murine Typhus
- The bacteria Rickettsia typhi is the causative agent of murine typhus, and it is transmitted by the bites of infected fleas, particularly those that infest rodents 1.
- The main reservoir for this disease is rodents, particularly rats, hence the name "murine" which refers to rodents.
- Symptoms of murine typhus include fever, headache, body aches, and sometimes a rash that begins on the trunk and spreads to the extremities.
- The standard treatment for murine typhus is doxycycline, typically prescribed at 100 mg twice daily for 7-14 days, although alternative antibiotics like chloramphenicol may be considered for children under 8 years old or pregnant women.
Prevention and Control Measures
- Prevention of murine typhus focuses on controlling rodent populations and using flea control measures in areas where the disease is endemic.
- Early treatment is crucial as it shortens the duration of illness and prevents complications, with the disease being rarely fatal if left untreated 1.
- It is essential to note that while the provided evidence discusses various diseases, including plague, the focus remains on murine typhus, and the information regarding plague is not directly relevant to the question at hand.
Treatment and Management
- The standard treatment for murine typhus is doxycycline, typically prescribed at 100 mg twice daily for 7-14 days, with alternative antibiotics like chloramphenicol considered for specific patient groups.
- Early treatment is vital to prevent complications and shorten the duration of illness.
- The bacteria infects endothelial cells lining blood vessels, causing inflammation throughout the body, which explains the widespread symptoms of murine typhus.
From the Research
Definition and Cause of Murine Typhus
- Murine typhus is an acute febrile illness caused by Rickettsia typhi, an obligately intracellular Gram-negative coccobacillus 2, 3, 4.
- The disease is usually transmitted by the fleas of rodents, but in some areas, opossums and cats can serve as reservoirs of infection, with the cat flea (Ctenocephalides felis) being the principal vector 3, 4.
Transmission and Epidemiology
- Humans become infected when R. typhi-infected flea feces are rubbed into flea bite wounds or onto mucous membranes 2.
- Murine typhus is endemic throughout much of the world, especially in tropical and subtropical seaboard regions where rats are common 2.
- In the United States, cases are concentrated in suburban areas of Texas and California, with a seasonal distribution of cases during warmer months 3, 5.
Clinical Manifestations and Diagnosis
- The disease is characterized by non-specific symptoms such as fever, headache, and rash, although the classic triad is only encountered in about one-third of patients 5.
- Other frequent symptoms include chills, malaise, myalgia, and anorexia 5.
- Laboratory abnormalities may include elevated liver enzymes, lactate dehydrogenase, erythrocyte sedimentation rate, and hypoalbuminemia 5.
- Serology is the mainstay of diagnostic testing, with confirmation usually requiring demonstrating seroconversion or a fourfold increase in antibody titer from acute- and convalescent-phase sera 2.
Treatment and Outcomes
- Doxycycline is the antibiotic of choice for treating murine typhus, and early empiric treatment is imperative 2, 3, 6.
- Azithromycin has been shown to be inferior to doxycycline as oral therapy for uncomplicated murine typhus 6.
- Complications occur in about one-quarter of patients, but reported mortality is extremely low 5.