LETTERS

Rat-bite Fever, Physical examination showed cles, and pustules on the extremities; superficial scratches from the rat; soles and palms are frequently Canada temperature of 39.6°C; heart rate of involved. Joint symptoms range from To the Editor: Rat-bite fever was 102 bpm; swelling, erythema, and polyarthralgia to migratory pol- once considered an exclu- decreased range of motion in several yarthritis with purulent effusions. A sive to children living in poverty; joints; and pustular lesions on the nonsuppurative migratory polyarthri- ≈ however, dense urban housing and soles of the feet. tis occurs in 50% of patients (5,7). changing pet-keeping practices may The patient’s leukocyte count was In rare cases, rash and arthritis may × 9 be altering this profile (1,2). To date, 8.3 10 /L. Synovial fluid from the be absent (8). × 6 ≈200 cases of rat-bite fever have been knee showed 45.5 10 /L leukocytes When S. minus (a spirochete) is reported in the United States (3), and with 89% neutrophils; the culture introduced by rat bite, the bite wound a recent study reported a 2-fold showed no growth. Gram stains of initially heals but then ulcerates, fol- increased incidence in California dur- blood and pustule swabs showed lowed by regional lymphadenopathy ing the 1990s (1). We report on 2 large, pleomorphic, gram-negative and a distinctive rash of red and pur- cases that occurred in Ontario, bacilli with long filaments and irregu- ple plaques. Arthritic symptoms are Canada, in the early 2000s. lar swellings. Growth occurred on the rare (9). The first case occurred in a previ- after 28 hours of aerobic Complications of rat-bite fever ously healthy 29-year-old man who incubation at 35°C in 10% horse include destructive joint disease, peri- was bitten on the finger by a pet rat. serum. Characteristic puff-ball carditis, , abscesses, The wound healed spontaneously. colonies of monili- pneumonia, parotitis, pancreatitis, After 24 hours, fever and emesis devel- formis were seen in supplemented and, rarely, and amnionitis. oped; 4 days later, diffuse maculopapu- thioglycolate broth. Development of endocarditis results lar rash and migratory arthritis of the Identification of the organism was in a mortality rate of up to 50% (5). knees, ankles, and finger joints ensued. confirmed by using the Sherlock S. moniliformis can be isolated and Physical examination showed a macu- (MIDI Inc., Newark, DE, USA) sys- cultured from synovial fluid, blood, lopapular rash over the lower extremi- tem. The major cellular fatty acid and abscesses. By contrast, S. minus ties, an effusion of the left knee, and a components of the isolate matched an has not been recovered on artificial warm, erythematous left ankle. S. moniliformis reference strain. The media but can be seen by using dark- Laboratory investigations showed patient received and gen- field microscopy with Giemsa or hemoglobin level of 134 g/L, leuko- tamicin intravenously for 6 days and Wright stains. cyte count of 16.0×109/L, and neu- was discharged home with a 10-day Laboratory personnel must be trophil count of 13.8×109/L. Aspira- regimen of amoxicillin. One year notified when rat-bite fever is sus- tion of the knee produced 70 cm3 of later, she remained asymptomatic. pected because S. moniliformis does cloudy fluid; synovial fluid analysis Rat-bite fever commonly results not grow in a routine sheep blood or showed 666×106/L leukocytes with a from infection with the zoonotic MacConkey agar; it requires rat or predominance of neutrophils. pathogens S. moniliformis and horse serum, defibrinated blood, or Ceftriaxone, 2 g once a day, was Spirillum minus. S. moniliformis is ascitic fluid to sustain growth. Growth given intravenously for 7 days. more common in Western countries, of S. moniliformis is inhibited by sodi- Although symptoms improved within and S. minus predominates in Asia um polyanetholesulfonate, a sub- 24 hours, the effusion recurred within (3). S. moniliformis colonizes the stance that is added to blood culture 48 hours of discontinuing the initial nasopharynx of healthy rats (4) and is bottles to inhibit the antimicrobial course of ceftriaxone. The knee was transmitted by the bite or scratch of action of blood (4,8). surgically drained, and ceftriaxone rats, squirrels, mice, guinea pigs, and, Optimal treatment for rat-bite was continued for 5 weeks. Systemic rarely, cats and other rodent preda- fever is penicillin G given intra- symptoms and the effusion resolved. tors. Occasionally, it is transmitted by venously for 7 to 10 days, followed by The second case occurred in a pre- ingestion of contaminated milk or penicillin V taken orally for 7 days. viously healthy 9-year-old girl who water. (5,6). The site of inoculation Alternatively, tetracycline may be had mucosal contact with a pet rat. with S. moniliformis usually heals used (5,7,9). She sought treatment after 7 days of before systemic symptoms develop. Although rat-bite fever is uncom- generalized maculopapular and pustu- After the incubation period of 1 to 22 mon, it is increasingly seen as a result lar rash and 10 days of fever and days, patients experience fever, of changing patterns of urban living headache. She had an associated chills, myalgia, headache, and rash. and pet-keeping practices. If unrec- asymmetric, migratory arthritis. The rash consists of macules, vesi- ognized, this infection can have

Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 12, No. 8, August 2006 1301 LETTERS debilitating sequelae and can be life Cutaneous Injury (76%) patients had disease onset from threatening. May through August, the summer sea- and Vibrio son in Hong Kong. Fifteen (52%) Michael E. Schachter,* vulnificus Infection cases were in men, and the median Lindsay Wilcox,* Neil Rau,† age was 70 years (range 24–82 years). Deborah Yamamura,*‡ To the Editor: Vibrio vulnificus Fifteen (52%) patients had underlying Shirley Brown,§ infection is transmitted by eating con- illnesses that were known to predis- and Christine H. Lee* taminated seafood or by exposure to pose them to V. vulnificus infection, *McMaster University, Hamilton, Ontario, seawater through an open wound (1). including chronic liver disease (30%), Canada; †Halton Healthcare Services, Among immunocompromised per- chronic renal failure (15%), diabetes Oakville-Trafalgar Memorial Site, Oakville, sons, especially those with chronic Ontario, Canada; ‡MDS Diagnostic mellitus (7%), and thalassemia major liver disease, V. vulnificus can cause a (3%). Fourteen (48%) patients were Services, Toronto, Ontario, Canada; and life-threatening illness characterized §Toronto Public Health Laboratories, previously healthy. No significant dif- Toronto, Ontario, Canada by blistering skin lesions, necrotizing ferences in age and sex were found. fasciitis, and septic shock (2–5). References Among the 14 previously healthy However, the epidemiology and risk patients, the consequences of V. vul- 1. Graves MH, Janda MJ. Rat-bite fever factors for severe forms of V. vulnifi- nificus infection included necrotizing (Streptobacillus moniliformis): a potential cus infection among healthy persons emerging disease. Int J Infect Dis. 2001;5: fasciitis (70%), severe cellulitis (7%), are less well documented (4–6). primary septicemia (14%), and gas- 151–4. We conducted a retrospective clin- 2. Morse SS. Factors in the emergence of troenteritis (7%). Two patients who infectious disease. Emerg Infect Dis. ical record review of V. vulnificus had necrotizing fasciitis and 1 patient 1995;1:7–15. in persons admitted to all 3. Freels LK, Elliott SP. Rat bite fever: three with primary septicemia died. public hospitals from January 1, 2003, Compared with patients with predis- case reports and a literature review. Clin through August 31, 2005, in Hong Pediatr (Phila). 2004;43:291–5. posing medical conditions, patients 4. Salmon RL, McEvoy MB. Rat-bite fevers. Kong, which has a population of >6 with a history of good health had a In: Zoonosis. Palmer SR, Soulsby S, million persons. We defined a case- Simpson DIH, editors. Toronto: Oxford higher (but not significant) proportion patient as a patient with culture of V. of necrotizing fasciitis (70% vs 47%, Medical Publications; 1998. p. 187–90. vulnificus from any clinical specimen. 5. Hambridge SJ, Ogle JW. Index of suspi- p = 0.12), a lower proportion of sep- cion. Case 1. Diagnosis: rat-bite fever. A record search of clinical case notes ticemia (14% vs. 27%, p = 0.26), and Pediatr Rev. 2001;22:95–103. was performed through a computer- 6. Parker F Jr, Hudson HP. The etiology of an equal number of severe cases of ized clinical management system cellulitis (7% vs. 7%). Furthermore, Haverhill fever (erythema arthriticum epi- maintained by the Hospital Authority, demicum). Am J Pathol. 1926;2:357–79. fewer patients with a history of good 7. Washburn R. Streptobacillus moniliformis which manages all public hospitals in health died than did patients with pre- (Rat-bite fever). In: Mandell GL, Bennett Hong Kong. For each case-patient JE, Dolin R, editors. Principles and practice disposing illnesses (21% vs. 33%, p = identified, we reviewed demographic 0.25). The median duration between of infectious diseases. 5th ed. Toronto: data (age, sex, occupation, residence), Churchill Livingstone Inc.; 2000. p. symptom onset and admission for all 2422–4. clinical and laboratory data (date of patients was 1 day (range 0–3 days), 8. Lambe DW Jr, McPhedran AM, Mertz JA, onset, symptoms, laboratory investi- Stewart P. Streptobacillus moniliformis iso- with no significant difference between gation findings, diagnosis, outcome), the 2 groups. lated from a case of Haverhill fever: bio- and potential risk factors (past health chemical characterization and inhibitory A history of cutaneous injury or a effect of sodium polyanethol sulfonate. Am and possible source of exposure) skin prick from a seafood part (e.g., J Clin Pathol. 1973;60:854–60. associated with the case. We com- 9. Committee on Infectious Diseases, fish fin, shrimp spine, or crab leg) was pared previously healthy patients with significantly more common among American Academy of Pediatrics. 2003 Red patients who had predisposing med- book: Report of the Committee on previously healthy patients than Infectious Diseases. 26th ed. Elk Grove ical conditions in terms of demo- among patients with predisposing ill- Village, IL: The American Academy of graphic profile, clinical signs and nesses (70% vs. 27%, p = 0.02). Ten Pediatrics; 2000. p. 482–3. symptoms and outcome, and known (83%) of the 12 previously healthy exposure factors. Mann-Whitney U patients with necrotizing fasciitis and Address for correspondence: Christine H. Lee, χ2 tests, tests, or Fisher exact tests septicemia reported a history of cuta- Department of Pathology and Molecular were used to detect significant differ- Medicine, McMaster University, St. Joseph’s neous injury. The corresponding pro- ences (α = 0.05). Healthcare, 50 Charlton Ave East, Hamilton, portion was significantly lower (31%) We identified 29 cases over the 32- Ontario L8N 4A6, Canada; email: clee@ among patients with predisposing mcmaster.ca month study period. Twenty-two medical conditions (p = 0.01). Among

1302 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 12, No. 8, August 2006