rat-bite fever

Rat-Bite Fever 

Definition

Rat-bite fever refers to an infection which develops after having been bitten or scratched by an infected animal.

Description

Rat-bite fever occurs most often among laboratory workers who handle lab rats in their jobs, and among people who live in poor conditions, with rodent infestation. Children are particularly likely to be bitten by rodents infesting their home, and are therefore most likely to contract rat-bite fever. Other animals that can carry the types of bacteria responsible for this illness include mice, squirrels, weasels, dogs, and cats. One of the causative bacteria can cause the same illness if it is ingested, for example in unpasteurized milk.

Causes and symptoms

There are two variations of rat-bite fever, caused by two different organisms. In the United States, the bacteria Streptobacillus moniliformis is the most common cause (causing streptobacillary rat-bite fever). In other countries, especially Africa, Spirillum minus causes a different form of the infection (called spirillary rat-bite fever).

Streptobacillary rat-bite fever occurs up to 22 days after the initial bite or scratch. The patient becomes ill with fever, chills, nausea and vomiting, headache, and pain in the back and joints. A rash made up of tiny pink bumps develops, covering the palms of the hands and the soles of the feet. Without treatment, the patient is at risk of developing serious infections of the lining of the heart (endocarditis), the sac containing the heart (pericarditis), the coverings of the brain and spinal cord (meningitis), or lungs (pneumonia). Any tissue or organ throughout the body may develop a pocket of infection and pus, called an abscess.

Spirillary rat-bite fever occurs some time after the initial injury has already healed, up to about 28 days after the bite or scratch. Although the wound had appeared completely healed, it suddenly grows red and swollen again. The patient develops a fever. Lymph nodes in the area become swollen and tender, and the patient suffers from fever, chills, and headache. The skin in the area of the original wound sloughs off. Although rash is less common than with streptobacillary rat-bite fever, there may be a lightly rosy, itchy rash all over the body. Joint and muscle pain rarely occur. If left untreated, the fever usually subsides, only to return again in repeated two-to four-day cycles. This can go on for up to a year, although, even without treatment, the illness usually resolves within four to eight weeks.

Diagnosis

In streptobacillary rat-bite fever, found in the United States, diagnosis can be made by taking a sample of blood or fluid from a painful joint. In a laboratory, the sample can be cultured, to allow the growth of organisms. Examination under a microscope will then allow identification of the bacteria Streptobacillus moniliformis.

In spirillary rat-bite fever, diagnosis can be made by examining blood or a sample of tissue from the wound for evidence of Spirillum minus.

Treatment

Shots of procaine penicillin G or penicillin V by mouth are effective against both streptobacillary and spirillary rat-bite fever. When a patient is allergic to the penicillins, erythromycin may be given by mouth for streptobacillary infection, or tetracycline by mouth for spirillary infection.

Prognosis

With treatment, prognosis is excellent for both types of rat-bite fever. Without treatment, the spirillary form usually resolves on its own, although it may take up to a year to do so.

The streptobacillary form, found in the United States, however, can progress to cause extremely serious, potentially fatal complications. In fact, before antibiotics were available to treat the infection, streptobacillary rat-bite fever frequently resulted in death.

Prevention

Prevention involves avoiding contact with those animals capable of passing on the causative organisms. This can be an unfortunately difficult task for people whose economic situations do not allow them to move out of rat-infested buildings. Because streptobacillary rat-bite fever can occur after drinking contaminated milk or water, only pasteurized milk, and water from safe sources, should be ingested.

Key terms

Abscess — A pocket of infection; a collection of pus.

Endocarditis — An inflammation of the lining of the heart.

Meningitis — An inflammation of the tissues covering the brain and spinal cord.

Pasteurization — A process during which milk is heated up and maintained at a particular temperature long enough to kill bacteria.

Pericarditis — An inflammation of the sac containing the heart.

Resources

Organizations

Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800) 311-3435, (404) 639-3311. http://www.cdc.gov.

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fever /fe·ver/ (fe´ver)

1. pyrexia; elevation of body temperature above the normal (37°C).

2. any disease characterized by elevation of body temperature.

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blackwater fever  a dangerous complication of falciparum malaria, with passage of dark red to black urine, severe toxicity, and high mortality.

boutonneuse fever  a tickborne disease endemic in the Mediterranean area, Crimea, Africa, and India, due to infection with Rickettsia conorii, with chills, fever, primary skin lesion (tache noire), and rash appearing on the second to fourth day.

cat-scratch fever  see under disease.

central fever  sustained fever resulting from damage to the thermoregulatory centers of the hypothalamus.

childbed fever  puerperal septicemia.

Colorado tick fever  a tickborne, nonexanthematous, febrile, viral disease caused by an arenavirus and seen in the Rocky Mountain area of the United States.

continued fever  one that varies only slightly in 24 hours.

Crimean-Congo hemorrhagic fever  a hemorrhagic fever caused by the Crimean-Congo hemorrhagic fever virus, transmitted by ticks and by contact with blood, secretions, or fluids from infected animals or humans; it occurs in the Crimea, Central Asia, and regions of Africa.

drug fever  febrile reaction to a therapeutic agent, such as a vaccine, antineoplastic, or antibiotic.

elephantoid fever  a recurrent acute febrile condition occurring with filariasis; it may be associated with elephantiasis or lymphangitis.

enteric fever  any of a group of febrile illnesses associated with enteric symptoms caused by salmonellae, especially typhoid fever and paratyphoid fever.

epidemic hemorrhagic fever  an acute infectious disease characterized by fever, purpura, peripheral vascular collapse, and acute renal failure, caused by viruses of the genus Hantavirus, thought to be transmitted to humans by contact with saliva and excreta of infected rodents.

familial Mediterranean fever  a hereditary disease usually seen in Armenians and Sephardic Jews, with short recurrent attacks of fever, pain in the abdomen, chest, or joints, and erythema like that of erysipelas; it may be complicated by amyloidosis.

Haverhill fever  the bacillary form of rat-bite fever, due to Streptobacillus moniliformis, and transmitted through contaminated raw milk and its products.

hay fever  a seasonal form of allergic rhinitis, with acute conjunctivitis, lacrimation, itching, swelling of the nasal mucosa, nasal catarrh, and attacks of sneezing, an anaphylactic or allergic reaction excited by a specific allergen (such as pollen).

hemorrhagic fevers  a group of diverse, severe viral infections seen around the world but mainly in the tropics, usually transmitted to humans by arthropod bites or contact with virus-infected rodents; they all have certain common features, including fever, hemorrhagic manifestations, thrombocytopenia, shock, and neurologic disturbances.

humidifier fever  malaise, fever, cough, and myalgia caused by inhalation of air that has been passed through humidifiers, dehumidifiers, or air conditioners contaminated by fungi, amebas, or thermophilic actinomycetes.

intermittent fever  an attack of malaria or other fever, with recurring fever episodes separated by times of normal temperature.

Katayama fever  fever associated with severe schistosomal infections, accompanied by hepatosplenomegaly and by eosinophilia.

Lassa fever  a highly fatal, acute, febrile disease seen in West Africa, caused by a virulent arenavirus and characterized by increasing prostration, sore throat, ulcerations of the mouth or throat, rash, and general aching.

metal fume fever  a disease of welders and others working with volatilized metals, marked by sudden thirst, metallic taste in the mouth, high fever with chills, sweating, and leukocytosis.

mud fever  a type of leptospirosis seen in workers in flooded fields and swamps in Germany and Russia.

nonseasonal hay fever , hay fever, perennial nonseasonal allergic rhinitis.

Oroya fever  see Carrión's disease.

paratyphoid fever  paratyphoid.

parenteric fever  a disease clinically resembling typhoid fever and paratyphoid, but not caused by Salmonella.

parrot fever  psittacosis.

pharyngoconjunctival fever  an epidemic disease due to an adenovirus, seen mainly in school children, with fever, pharyngitis, conjunctivitis, rhinitis, and enlarged cervical lymph nodes.

phlebotomus fever  a febrile viral disease of short duration, transmitted by the sandfly Phlebotomus papatasi, with dengue-like symptoms, seen in Mediterranean and Middle Eastern countries.

Pontiac fever  a self-limited disease marked by fever, cough, muscle aches, chills, headache, chest pain, confusion, and pleuritis, caused by a strain of Legionella pneumophila.

pretibial fever  an infection due to a serovar of Leptospira interrogans, marked by a rash on the pretibial region, with lumbar and postorbital pain, malaise, coryza, and fever.

puerperal fever  septicemia accompanied by fever, in which the focus of infection is a lesion of the mucous membrane of the parturient canal due to trauma during childbirth; usually due to a streptococcus.

Q fever  a febrile rickettsial infection, usually respiratory, first described in Australia, caused by Coxiella burnetii.

rat-bite fever  either of two clinically similar acute infectious diseases, usually transmitted through a rat bite, one form (bacillary) of which is caused by Streptobacillus moniliformis and the other form (spirillary) by Spirillum minor.

recurrent fever 

1. relapsing f.

2. recurrent paroxysmal fever occurring in various diseases, such as malaria.

relapsing fever  any of a group of infectious diseases due to various species of Borrelia, marked by alternating periods of fever and apyrexia, each lasting from five to seven days.

remittent fever  one that shows significant variations in 24 hours but without return to normal temperature.

rheumatic fever  a febrile disease occurring as a sequela to Group A hemolytic streptococcal infections, characterized by multiple focal inflammatory lesions of connective tissue structures, especially of the heart, blood vessels, and joints, and by Aschoff bodies in the myocardium and skin.

Rift Valley fever  a zoonotic febrile disease with dengue-like symptoms, due to an arbovirus, transmitted to humans by mosquitoes or by contact with diseased animals; first observed in the Rift Valley, Kenya.

Rocky Mountain spotted fever  infection with Rickettsia rickettsii, transmitted by ticks, marked by fever, muscle pain, and weakness followed by a macular petechial eruption that begins on the hands and feet and spreads to the trunk and face, with other symptoms in the central nervous system and elsewhere.

rose fever  a form of hay fever caused by grass pollens released while roses or other flowers are blooming.

scarlet fever  an acute disease caused by Group A β-hemolytic streptococci, marked by pharyngotonsillitis and a skin rash caused by an erythrogenic toxin produced by the organism; the rash is a diffuse, bright red erythema, and desquamation of the skin begins as fine scaling with eventual peeling of the palms and soles.

Sennetsu fever  a febrile disease seen in Japan and Malaysia and caused by Ehrlichia sennetsu, characterized by headache, nausea, lymphocytosis, and lymphadenopathy.

septic fever  fever due to septicemia.

South African tickbite fever  boutonneuse f.

trench fever  a louse-borne rickettsial disease due to Bartonella quintana, transmitted by the body louse, Pediculus humanus corporis, and characterized by intermittent fever, generalized aches and pains, particularly severe in the shins, chills, sweating, vertigo, malaise, typhus-like rash, and multiple relapses.

typhoid fever  infection by Salmonella typhi chiefly involving the lymphoid follicles of the ileum, with chills, fever, headache, cough, prostration, abdominal distention, splenomegaly, and a maculopapular rash; perforation of the bowel may occur in untreated cases.

fever of unknown origin  (FUO) a febrile illness of at least three weeks' duration (some authorities permit a shorter duration), with a temperature of at least 38.3°C on at least three occasions and failure to establish a diagnosis in spite of intensive inpatient or outpatient evaluation (three outpatient visits or three days' hospitalization).

West Nile fever  see under encephalitis.

yellow fever  an acute, infectious, mosquito-borne viral disease, endemic primarily in tropical South America and Africa, marked by fever, jaundice due to necrosis of the liver, and albuminuria.

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rat-bite fever

n.

Headache, fever, lymphangitis, and lymphadenitis following the bite of a rat or other rodent, due either to a spirillum or to Streptobacillus moniliformis.

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rat-bite fever

Etymology: AS, raet + bitan, to bite

either of two distinct infections transmitted to humans, commonly by the bite of a rat or mouse but also by contact with excretions of the mouth, nose, or urine of an infected animal. It is characterized by fever, headache, malaise, nausea, vomiting, and rash. In the United States the disease is more commonly caused by Streptobacillus moniliformis. Its unique features are a rash on palms and soles, painful joints, prompt healing of the wound, and a duration of 2 weeks. If left untreated, severe complications may occur, such as infection of the heart valves. In the Far East, rat-bite fever is usually caused by Spirillum minus and is associated with an asymmetric rash on the extremities, no joint symptoms, a relapsing fever, swelling at the site of the wound, regional lymphadenopathy, and a duration of 4 to 8 weeks. Relapse is common. Penicillin administered intramuscularly is effective in treating either form of the disease. Rat-bite fever resulting from infection caused by Streptobacillus moniliformis is also called Haverhill fever. Infection caused by Spirillum minus is also called sodoku.

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rat-bite fever

Infectious disease Either of 2 similar systemic bacterial infections caused by different gram-negative facultative anaerobes 1. Streptobacillary RBF–caused by infection with Streptobacillus moniliformis, transmitted in crowded urban environs by ingesting milk contaminated by rat feces; S moniliformis is present in the nasopharynx of up to 50% of healthy lab and wild rodents Clinical 2-10 day incubation followed by an irregularly relapsing fever and asymmetric polyarthritis followed within 2-4 days by a maculopapular rash on extremities, palmoplantar surfaces; bite wound heals spontaneously; headache, N&V, myalgia, minimal regional lymphadenopathy, anemia, endocarditis, myocarditis, meningitis, pneumonia, and focal abscesses may occur; most cases resolve spontaneously within 2 wks, 13% of untreated cases are fatal Diagnosis Streptobacillary RBF can only be diagnosed by blood culture; S moniformis is a slow grower with strict growth requirements, making it difficult for most labs to culture; no serologic test is available; biological false positives for syphilis occur Management Penicillin, tetracycline, streptomycin 2. Spirillary RBF caused by Spirillum minus which occurs worldwide, but is most common in Asia; it has a longer incubation period (1-3 weeks), rare arthralgia, and an inoculation wound which can reappear at the onset of Sx or persist with edema and ulceration Management Penicillin, tetracycline, streptomycin. See Sodoku.