NAME: Streptobacillus moniliformis.
SYNONYM OR CROSS REFERENCE: Streptobacilliosis, streptobacillary fever, Haverhill fever, epidemic arthritic erythema, and rat bite fever (1-4), known as sodoku in Japan (4).
CHARACTERISTICS: A gram-negative bacillus. S. moniliformis is a facultative anaerobe that is morphologically variable and frequently occurs in chains or filaments (5-9). Its dimensions vary from 0.1 - 0.5 µm in width by 2.0 - 5.0 µm length, and can be up to 10 – 15 µm in length (5, 6).
PATHOGENICITY/TOXICITY: S. moniliformis can cause a systemic infection with an abrupt onset, with symptoms including fever (38°C to 41°C), headache, nausea, vomiting, sore throat, arthralgia, and myalgias (1, 5, 9). Two to 4 days after onset, a maculopapular rash and local ulceration may develop on the extremities, with interstitial pneumonia, lymph node sinus hyperplasia, metastatic abscesses, and anaemia (3, 5, 10). Other complications include systemic vasculitis, hepatitis, and nephritis (5). Immunocompromised patients may experience pericarditis, endocarditis, myocarditis, meningitis, septic arthritis, and focal abscesses (10). If untreated, severe manifestations can include endocarditis, myocarditis, meningitis, pneumonia, sepsis, and death (5). In children, a subglottic mass and bilateral parotid swelling may occur (11).
Symptoms of Haverhill fever include severe vomiting and pharyngitis, and other symptoms of rat bite fever (3). The mortality rate of untreated rat bite fever is approximately 7% to 13% (1, 5).
EPIDEMIOLOGY: Worldwide (2, 3). Over 50% of reported cases in the United States were children (5), and may be associated with sleeping in rat-infested dwellings.
HOST RANGE: Humans, rats, and other animals (guinea pigs, ferrets, mice, squirrels, weasels, gerbils). There is also evidence of infection in dogs, cats, turkeys, koalas and non-human primates (monkey and macaque) (2, 3, 5, 9, 12).
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: Contact with, or consumption of, urine, secretions of the mouth (saliva), nose, eyes, the milk of an infected animal, or via an animal bite or scratch. Ingesting food, water, or drinks contaminated with rat excrement can also spread the infection (2, 9, 10).
INCUBATION PERIOD: Two to 10 days, rarely longer, but typically less than 7 days (1-3, 5).
COMMUNICABILITY: No evidence for direct human-to-human transmission (1).
ZOONOSIS: Yes from rats and other infected animals (5, 10, 12).
VECTORS: None.
DRUG SUSCEPTIBILITY: Penicillin is the drug of choice (5). S. moniliformis is sensitive to a variety of other antibiotics, including penicillin, ampicillin, streptomycin, tetracycline, doxycycline, and cephalosporin (1, 5, 9, 13).
SUSCEPTIBILITY TO DISINFECTANTS: Sensitive to 70% (v/v) ethanol, sodium hypochlorite (500 to 1,000 ppm free chlorine), accelerated hydrogen peroxide, and quaternary ammonium compounds (14, 15).
PHYSICAL INACTIVATION: Sensitive to moist heat (121°C for at least 15 minutes) and dry heat (160 to 170°C for at least l hour) (16).
SURVIVAL OUTSIDE HOST: Can be stored deep-frozen, or lyophilized for at least several days (9).
SURVEILLANCE: Monitor for symptoms. Infection can be confirmed by culture/isolation, PCR, serological tests, complement fixation, and/or immunofluorescence (3, 7, 12).
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Treat with the appropriate antibiotic, for example, penicillin, ampicillin, streptomycin, or tetracycline (1, 9, 10).
IMMUNIZATION: None.
PROPHYLAXIS: Rat bites should be promptly cleaned and disinfected and tetanus toxoid should be administered (1). Penicillin or doxycycline can also be used for prophylaxis following a rat bite (2).
LABORATORY-ACQUIRED INFECTIONS: Of 65 cases of documented cases of rat-bite fever since 1938, only 8 (12%) were attributed to laboratory rat exposure (5). Very few cases are documented each year (1).
SOURCES/SPECIMENS: Infected blood, synovial fluid, blister fluid, lymph node, and pus (1, 2, 7).
PRIMARY HAZARDS: Accidental parenteral inoculation, scratches or bites of infected animals, and contact with infected animals (1, 5, 10).
SPECIAL HAZARDS: Secretions of infected animals may create airborne droplets (5).
RISK GROUP CLASSIFICATION: Risk Group 2 (17).
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes (18).
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities (18).
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up (18).
DISPOSAL: Decontaminate all materials for disposal by steam sterilisation, chemical disinfection, or incineration (18).
STORAGE: In sealed containers that are appropriately labelled (18).
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: September 2010.
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright ©
Public Health Agency of Canada, 2010
Canada
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