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V.D. Moskaliuk, A.S. Sydorchuk, A.M.Sokol,

N.A. Bogachik, Ya.V. Venglovska

Bukovinan State Medical University, Chernivtsi

Clinical case study of rat bite fever

as an occupational disease

Rats bite fever – term that integrates two self-dependent illnesses, which caused by different pathogens, but still have common mechanism of transmission, similar pathogenesis and clinical picture – sodoku and streptobacillosis.

Rat-bite fever is an acute, febrile human illness caused by bacteria transmitted by rodents, rats in most cases, which is passed from rodent to human via the rodent's urine or mucous secretions. Alternative names for rat bite fever include streptobacillary fever, streptobacillosis, spirillary fever, sodoku, and epidemic arthritic erythema. It is a rare disease spread by infected rodents and can be caused by two specific types of bacteria. Most cases occur in Japan, but specific strains of the disease are present in the United States, Europe, Australia, and Africa. Some cases are diagnosed after patients were exposed to the urine or bodily secretions of an infected animal. These secretions can come from the mouth, nose, or eyes of the rodent. The majority of cases are due to the animal's bite. It can also be transmitted throughout food or water that is contaminated with rat feces or urine. Rats are not the only type of animal that can be infected with this disease. Others include weasels, gerbils, and squirrels. Household pets such as dogs or cats that are exposed to these animals can also carry the disease and infect humans. If a person is bitten by a rodent, it is important to quickly wash and cleanse the wound area thoroughly with antiseptic solution to reduce the risk of infection.

The first description of diseases, related to rat’s bites was appeared in Japan more than two thousands ago, japans called it “sodoku” (“so” – rat, “doku” - poison). In Europe, Asia rat bite fever caused by Spirochaeta minus, and in Northern and Southern America – by Streptobacillus moniliformis.

Disease is distributed across the geographic spectrum.

Sodoku – is a zoonotic disease from group of wound infection, caused by spirochaeta and characterized with recurrent fever, lymphadenopathy and rash.

Causative agent – is Spirochaeta minus of Aquaspirillum genus, short motile gram-negative spiral form bacteria. In environment is not stable.

Main source of disease naturally are rats as saprophytic microbe of oral cavity. Sick human isn’t dangerous for habitats, but potential infection during blood transfusion.

Susceptibility in humans is high, but disease also occurs sporadically with prevalence in hunters, plumbing specialist, and workers of veterinary control.

Causative agent ingress into organism through damaged skin. In the site of bite a reproduction and accumulation of agents are developed with the next lymphogenic distribution over an organism. Penetration of spirochaetes into different organs creates secondary foci. The protracted course and relapses of disease could be.

Cleaning of organism from agent is provided by working-up of non-specific factors of defence and formation of specific immunity.

The Streptobacillosis form of rat-bite fever is known by the alternative names Haverhill Fever and epidemic arthritic erythema. It is a severe disease caused by Streptobacillus moniliformis, transmitted either by rat bite or ingestion of contaminated products (Haverhill fever). After an incubation period of 2-10 days, Haverhill fever begins with high prostrating fevers, rigors, headache and polyarthralgia. Soon an exanthem appears, either maculopapular or petechial and arthritis of large joints can be seen. The organism can be cultivated in blood or articular fluid. The disease can be fatal if untreated in 20% of cases due to malignant endocarditis, meningoencephalitis or septic shock. Symptoms will be different for every person and will be different depending on the type of rat bite fever that a person is infected with. Both spirillary rat bite fever and streptobacillary rat bite fever have a few individual symptoms although most symptoms are crossovers. Streptobacillary is most commonly found in the United States and spirillary rat bite fever is generally diagnosed in patients in Africa and other countries. Rat bite symptoms are visually seen in most cases and include inflammation around the open sore. A rash can also spread around the area and appear red or purple. Other symptoms associated with streptobacillary rat bite fever include chills, fever, vomiting, headaches, and muscle aches. Joints can also become painfully swollen and pain can be experienced in the back. Along with rash and swollen joints, skin irritations like ulcers or inflammation can develop on the hands and feet. Wounds will heal slowly, so it is possible that symptoms will come and go over the course of a few months. It is important to contact a physician and report these symptoms immediately.

Symptoms associated with spirillary rat bite fever include issues with the lymph nodes. The lymph nodes which lie in the lymphatic system will often swell or inflame as a reaction to the disease or infection. The most common locations of lymph node swelling are in the neck, groin and underarm. Symptoms generally appear within two to ten days of exposure to the affected animal. It will begin with the fever and will progress to the rash that will appear on the hands and feet within two to four days. Rash will appear all over the body with this form of the infection and will rarely cause symptoms of joint pain.

This condition is diagnosed by detecting the bacteria in skin, blood, joint fluid, or lymph nodes. Blood antibody tests may also be used. To get a proper diagnosis for rat bite fever, different tests are run depending on the type of symptoms that are being experienced.

To diagnosis streptobacillary rat bite fever, blood or joint fluid is extracted and the organisms living in it are cultured. Diagnosis for spirillary rat bite fever is by direct visualization or culture of spirillum from blood smears or tissue from lesions or lymph nodes. Treatment of antibiotics is the same for both types of infection.

We aimed to present by the current issue the one clinical case of this infectious disease in scientist worker as the case of occupational pathology.

3 of July 2006 during experimental manipulation fulfilled the research with white rats of Wistar population it was happened the bite accident by one 110,0 g rat for the little finger of right hand.

Just afterwards the bite the wound was applied with spiritus solution (C2H5OH) few times and hydrogen peroxide solution (H2O2) and covered by sterile bandage. After one day the finger became swelling, the acute pain, hyperemia and purulent discharge had appeared.

And just after one week the common weakness, chills, headache, myalgia and arthralgia had occurred, and temperature had risen up to 40 C. The finger was swallowed more, it deeply red, and painful (Fig. 1). It was present the purulent discharge from the wound, deeply contraction of the little finger tissues and right hand.

Fig. 1. Maculo-papular rash elements and swelling of hand in patient with sodoku

From 12/07/2006 till 13/07/2006, common fatigue became more expressed, severe headache and severe joint and muscle pain over the body, temperature increase more than 40 C. The knee joints and talocrural joints became swelling, the small rash in the region of both talocrural and knee joints had appeared.

Pain in the joints lasts 5 days, because of severe swelling of knee and talocrural articulations it was impossible to move. Pain became more severe during walking; high temperature lasted more than 5 days. Patient used analgetics and antipyretics (tempalgin, dimedrol). His final diagnosis was proved by clinical and epidemiological data – sodoku. Since that time he was administered i/m benzylpenicillini in the dose 48 000 000 IU per course (6 mln IU lasted 8 days).

Fortunately patient became convalescent soon; his course of sodoku was moderate and typical without complications according to well-timed treatment.

At the end of our issue we could concluded, that sodoku is sporadic and rare infectious disease. Reservoirs of rat-bite fever (mice, rats) are wide spreading everywhere and could migrate to any continent with ships.

Advisably, serological methods of diagnostics should be wider used; otherwise cultivation method isn’t applicable in early treatment by antibiotics.

It is very necessary to be warning and in any case of bite to use emergent nonspecific chemoprophylaxis per os of penicillinum G up to 2 g per day during 3 days.