Typhus, flea-borne endemic

Typhus, flea-borne endemic is transmitted by rat fleas. This disease can be prevented by applying insecticides to "rat runs, burrows and harborages." To lessen human exposure to fleas, kill fleas first, then rats. Patients have a flu-like illness. A rash appears later in 50%-89% of patients.

CASES/YEAR
750 (US); 15,000 (Global)
CATEGORY
AGENT TYPE
Rickettsiae
OTHER NAMES
Murine typhus; Shop typhus; Rickettsia typhi (Rickettsia mooseri) infection; Rickettsia felis infection;
ACUITY
Acute-Moderate
INCUBATION
1-2 weeks, usually about 12 days; [CCDM]
INITIAL SYMPTOMS
Flu-like illness with fever, headache, and myalgias; A rash appears later in 50%-89% of patients. Children are more likely to have nausea, vomiting, and abdominal pain. [CCDM]
PRECAUTIONS
Standard; "Not transmitted from person to person." [CDC 2007 Guideline for Isolation Precautions]
COMMENTS
FINDINGS:
The macular rash starts 5-6 days after onset of the fever, appearing on the trunk, legs, and arms. It is present in more than 50% of cases. Splenomegaly, hepatomegaly, thrombocytopenia, and mildly elevated liver transaminases are common. Pneumonia and encephalitis are occasionally reported as complications. [ID, p. 1486-7] Other findings in a series of cases from Thailand, Texas, and Greece included abdominal pain (11% to 31%), vomiting (23% to 40%), jaundice (3% to 11%), and seizures (2% to 4%). The rash may not be visible in dark-skinned patients. Effects on the eye in endemic typhus include keratoconjunctivitis and uveitis. Hematemesis and cerebral hemorrhage are severe manifestations. [Guerrant, p. 1001, 331] Neurological symptoms include confusion, stupor, seizures, and ataxia. The rash is usually maculopapular and occasionally petechial. Some patients have leukopenia early and leukocytosis after the first week. Other complications are myocarditis, meningoencephalitis, renal failure, and respiratory failure. [PPID, p. 2374] Some patients, especially those with G6PD deficiency, may have hemolysis and anemia. [Cecil, p. 2022]

EPIDEMIOLOGY:
Transmitted by rat fleas, this disease can be prevented by applying insecticides to "rat runs, burrows and harborages." To lessen human exposure to fleas, kill fleas first, then rats. Animal reservoirs include rats, mice and possibly other small or medium sized mammals. "Occasionally, a case may follow inhalation of dried infective flea feces." [CCDM, p. 665] Fewer than 80 cases per year are reported in the USA peaking in late summer and autumn with a high proportion of cases in Texas and southern California. [ID, p. 1487]
DIAGNOSTIC
Paired serology (antibodies usually positive in the 2nd or 3rd week); Weil-Felix agglutination test not recommended; IHC and PCR can detect typhus in skin biopsy samples of rash sites. [CCDM, p. 661-2]
SCOPE
Global; occurs anywhere buildings are inhabited by rats and people; [CCDM] More prevalent in coastal cities in tropical and subtropical regions; [PPID, p. 2372]
SIGNS & SYMPTOMS
  • >arthralgia
  • >fever
  • >myalgia
  • G abdominal pain
  • G hematemesis
  • G hepatomegaly
  • G jaundice
  • G liver function test, abnormal
  • G nausea, vomiting
  • H anemia
  • H hemolysis
  • H leukocytosis
  • H leukopenia
  • H splenomegaly
  • H thrombocytopenia
  • N confusion, delirium
  • N headache
  • N lethargy
  • N seizure
  • O conjunctivitis, acute
  • R cough
  • S papules or plaques
  • S petechiae and ecchymoses
  • S rash (exanthem)
  • X lung infiltrates
  • X pleural effusions
  • *acute renal failure
  • *ARDS
  • *encephalitis
  • *meningitis
  • *myocarditis
  • *pneumonia
  • *stupor, coma
  • *uveitis
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Inhalation
VECTOR
Fleas
SOURCE
Animal Excreta
RESERVOIR
Cats, Rodents, Wild Animals
RISK FACTORS
  • Travel to endemic area
  • Victim--air release of infectious agents
  • Work in a medical or research lab
  • Work in building infested with rodent fleas or mites
REFERENCES FOR CASES/YEAR
1. (US) Murine typhus still prevalent in the SE and Gulf Coast states; [Gorbach, p. 400] 50-100 cases are reported each year, primarily in southern California and southern Texas; [Cecil, p. 2022] Use correction factor of 10 for reported diseases. 75 X 10 = 750;
2. (Global) Extremely common in SE Asia and North Africa; [Cecil, p. 2022] 7 cases were documented in Tunisia in 2005; 4 cases have been documented in Japan since the 1950s; Guesstimate: 20 X the US cases/yr = 15,000;