Published Date: 2007-08-16 10:00:09
Subject: PRO/AH/EDR> Murine typhus - USA (CA)
Archive Number: 20070816.2677
MURINE TYPHUS - USA (CALIFORNIA)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Tue 14 Aug 2007
Source: ktla.com [edited]
Flea-Born Typhus Found in Orange County
Orange County health officials warned people today to control fleas,
in the wake of endemic typhus cases that led to hospital stays for an
adult and a minor in Westminster and a Huntington Beach resident. The
3 victims, who were not identified, are back home recovering from the
flea-born illness that can lead to meningitis and encephalitis, but
is not fatal without underlying health issues, said Howard Sutter of
the Orange County Health Care Agency.
Endemic typhus occurs naturally in Southern California, and 2 cases
were reported in Orange County earlier this year , Sutter said.
Other cases have been reported in Long Beach and other locations in
Los Angeles County, he said.
The disease, which is detected through a blood test, is transmitted
by the bite of infected fleas that may be found on opossums, rodents
and cats, he said. It is not transmitted from person to person and is
treatable with antibiotics, Sutter said, adding that symptoms include
fever, headache, muscle ache and rash.
Precautions urged by the health department include:
- treating pets and other domestic animals with flea medicine;
- avoiding contact with opossums, rodents, feral cats and other
animals that could harbor fleas;
- sealing off openings to attics and crawl spaces and keeping vent
screens in good repair to prevent wild animals from getting inside;
- reporting dead opossums, cats or other animals to animal control
agencies for removal;
- removing or trimming overgrown vegetation or ground cover where
wild animals may hide or nest; and
- keeping trash cans covered at all times and eliminating outdoor
food and water sources, including pet food, bird feeders and fallen
fruit from trees.
ProMED Rapporteur Joseph Dudley
[Rickettsia are small obligate intracellular parasites that are
maintained in animal and arthropod reservoirs, and transmitted by
arthropod vectors (ticks, fleas, lice or mites) to humans. _R. felis_
is the only one of the 12 members of the spotted fever group of
rickettsia, which are genetically closely related and are pathogenic
for humans, that is flea-borne. All of the other members of the
spotted fever group are tick-borne (e.g., _R. rickettsii_, the agent
of Rocky Mountain spotted fever, and _R. conorii_, the agent of
Indian, Kenya, and Israeli tick typhus, Marseilles fever, and
Astrakhan and Mediterranean spotted fever), except _R. akari_, the
agent of rickettsialpox, is mouse mite-borne.
Of the typhus group, _R. prowazekii_, the agent of epidemic typhus is
transmitted between humans by the human body louse and the reservoirs
are humans and flying squirrels and flying squirrel fleas; and _R.
typhi_, the agent of murine typhus, is transmitted by the rat flea
and the reservoir is the rat.
Fewer than 50 cases with clinical and epidemiologic findings
consistent with murine typhus are reported in the United States
annually, mainly from southern California (Los Angeles and Orange
County), central and south-central Texas, and Hawaii
murine typhus in the United States in the first half of the 20th
century was maintained by infected rats and rat fleas, absence of
these infected components of the transmission cycle subsequently
suggested alternate reservoirs and vectors (Adams WH, et al. Am. J
Trop Med Hyg 1970; 19:311-8; Schriefer ME, et al. J Clin Microbiol
1994; 54:949-54; Sorvillo FJ, et al. Am J Trop Med Hyg 1993;
Sero-positivity for _R. typhi_ in opossums and domestic cats
associated with human cases of typhus and heavy infestation of the
animals with cat fleas, which readily bite humans, suggested these as
alternate components of the transmission cycle in suburban
environments (Adams WH, et al. Am. J Trop Med Hyg 1970; 19:311-8).
_R. typhi_ was also demonstrated by PCR in opossums and cat fleas in
urban and suburban areas of Los Angeles. (Williams SG, et al. J Clin
Microbiol 1992; 30:1758-62). However, _R. felis_ (formerly called ELB
agent) has also been found in cat fleas and opossums in Texas and
Southern California in association with human murine typhus cases,
and _R. felis_ has been found by PCR in patients with murine
typhus-like illness (Schriefer ME, et al. J Clin Microbiol 1994;
Murine typhus presents abruptly with chills, fever and headache,
accompanied by rash, usually macular or maculopapular, and neurologic
involvement in some patients. The illness usually resolves within 3
weeks, even if untreated. However about 10 percent of patients are
sick enough to be hospitalized in an intensive care unit and up to 4
percent of hospitalized patients will die from the infection.
Treatment is doxycycline. Prevention is directed at control of flea
vectors and animal reservoirs, as outlined in the above news report.