Pneumonic Tularemia in Brooklyn, New York
By Michele Barry, MD, FACP
Dr. Barry is Professor of Medicine; Co-Director, International Health Program, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT.
Dr. Barry serves as a consultant for the Ford Foundation and receives funding for Johnson & Johnson.
Synopsis: The New York City Department of Health is investigating a laboratory confirmed case of pneumonic tularemia and asking medical providers to consider tularemia in patients spending time camping in Gateway National Recreation Area, part of which is located in Brooklyn, NY.
Source: Department of Health and Mental Hygiene (DOHMH) Alert #13–NYC June 11, 2008.
A Brooklyn, NY, resident presented in early June with a one-week history of fever, headaches, left-sided pleuritic chest pain, and a pleural effusion. Pleural fluid yielded a slow-growing Gram-negative bacterium that was identified as Francisella tularensis. The patient reported camping in Gateway National Recreation Area four days prior to onset of symptoms. (See Map, below.) This national park spans two states and three boroughs of New York City at the entrance to its outer harbor.
Commentary
Tularemia is a very rarely recognized disease in New York City; since 1965 there have been only 15 reported cases. In the United States approximately 100-200 cases occur annually, with a recent cluster of cases having occurring in 2000 at Martha's Vineyard, Massachusetts among landscapers presumably exposed to bacterial aerosols formed during mowing.1 Tularemia is a zoonotic infection among a variety of animal hosts, notably rabbits, aquatic rodents (muskrats, beaver, water voles), and other rodents, squirrels, skunks, and cats. A U.S. outbreak occurred among commercially sold prairie dogs in 2002.
F. tularensis can persist for weeks within contaminated water, soil, and vegetation and, at times, it can become airborne. It can also be found within amoebas such as Acanthamoeba species, which may represent an environmental reservoir for such. Humans can be accidentally infected by bites of infected ticks, deer flies, cats, ingestion of contaminated food or water, or by aerosols of bacteria from animals, such as those formed during mowing grassy areas. As few as 10 organisms can cause infection and disease. The typical incubation periods is 3-5 days, with a range of 1-14 days.
The clinical presentation of tularemia depends upon the route of exposure.
At least six distinct clinical syndromes or forms of tularemia have been recognized among infected patients:
- Ulceroglandular
- Glandular
- Typhoidal
- Pneumonic
- Oropharyngeal
- Oculoglandular.
Ulceroglandular tularemia occurs in 60-80% of cases; these patients usually report the handling of an animal or an animal bite, usually from a cat. Affected patients typically present with fever and a single papuloulcerative lesion with central eschar and tender regional lymphadenopathy. Glandular tularemia presents as enlargement of nodes, but without an obvious skin lesion. Typhoidal tularemia presents as bacterial sepsis with the occasional complication of hematogenous spread resulting in meningitis showing a mononuclear pleocytosis within cerebrospinal fluid. Pneumonic tularemia presents with pleural effusions and nodular infiltrates, although other parenchymal lung patterns have been described. Oropharyngeal tularemia occurs rarely and it is likely due to ingestion of poorly cooked animal meat. The diagnosis should be considered in patients with such a history and exudative pharyngitis unresponsive to penicillin. Oculoglandular disease has been attributed to inoculation of the eye by the accidental squirting of engorged fluid into eye during removal of the tick.
DOHMH in New York City has asked that any vacationer in areas such as Gateway National Park with unexplained pneumonia, sepsis or cutaneous ulcers associated with fever or regional lymphadenopathy be cultured for F. tularensis (biosafety level 2). Isolation of the organism is difficult as these bacteria are strictly aerobic and require enriched media (such as those containing cysteine and cystine or chocolate agar supplemented with IsoVitalex). Culture plates should be held for 5-7 days. Automated systems may misidentify the causative organisms as Pasteurella multocida. The drug of choice for treatment of tularemia is streptomycin 10 mg/kg administered IM every 12 hours for 7-10 days. Chloramphenicol has been added to the regimen when meningitis is present. For additional information see: http://www.bt.cdc.gov/agent/tularemia.
Reference
- Feldman KA, Ensore Re, Lathrop L et al. An Outbreak of Primary Pneumonic Tularemia on Martha's Vineyard. N Engl J Med 2001;345:1601.
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