Sodoku

SODOKU, disease of rat bite, in Japanese sodoku (from so-rat and doku-poison), sokosha, sokoshio, rat-bite fever, Rattenbisskrankheit, an illness caused by a spirochete (Spirillum minus), transmitted through the bite of an infected rat, characterized by periodically occurring fever attacks, accompanied by an inflammatory reaction at the site of the bite and a rash. The disease of rat bite was known in ancient times: it was known in India, Japan, and China. In the 19th century, it was described in America and Europe, as well as in other countries of the world. The causative agent of S. was discovered by Japanese researchers Futaki, Takaki, Taniguchi, and Osumi in 1916 (Futaki, Takaki, Taniguchi, Osumi) and named Spirochaeta morsus muris and by Ishiwara, Ohtawara, and Tamura in 1917 (Ishiwara, Ohtawara, Tamura). The spirochete found by the authors proved to be identical to the spirochete described in 1887 by Carter (Carter) in rats in India. Accordingly, the correct designation of the causative agent of S. is Spirillum minus Carter, 1887. In addition to the above mentioned, synonyms are Spirochaeta muris Wenyon, 1906, Spirochaeta laverani Breinl a. Kinghorn, 1906, Spirochaeta japonica Dujarric de la Riviere, 1918. Spirillum minus [see separate table (figure 3) to the article Streptococci] appears as a wavy line 1.5 to 3/µ (sometimes up to 5) µ-short forms, and up to 10-15 µ-long forms; about 0.2 µ thick. The length of this specimen depends on the number of its coils. The coils are uniform and tight. Their number varies from 1 to 9. In experimental animals, specimens with 10-19 coils are encountered. In the dark field and in preparations stained by silvering, bundles of long flagella are found at the ends of the spirochetes. Spirochetes possess strong mobility, they quickly move across the field of view and rotate around their axis. Unlike true spirochetes, their body is rigid and when moving, the spirochete does not bend. The vibrating nature of movement, characteristic of true spirochetes and leptospires, is absent in spirochetes. Spirillum minus multiplies by transverse division; it is easily stained by ordinary bacterial dyes; by Giemsa, it takes a bright pinkish-violet tint. In some cases in patients, in whose history there was a rat bite, fungi of the genus Streptothrix were found by various authors (Schottmuller, Blake, Ebert and Hesse). These fungi are widely distributed among rats (Tunnicliff). Some cases described as rat-bite disease may represent an independent disease-streptotrichal sepsis. The spirochete in human blood is rarely found directly under the microscope. It should be sought in a thick drop or one should use the enrichment method. According to Schuffner and Sieburg (Schuffner, Sieburg), citrated blood (equal amounts of blood and 2% solution of sodium citrate) is centrifuged three times, and the spirochetes are examined in the sediment. Spirochetes should also be sought in the tissue juice of edematous areas adjacent to the site of the bite, in the punctate of the regional lymph gland, or in sections of the spleen. To detect spirochetes, recourse is also had to intraperitoneal infection of laboratory animals with blood: guinea pigs (2-3 cm³) and mice (0.5 cm³). In mice, spirochetes appear in the blood approximately 10 days after infection. Large amounts of spirochetes are also found in the abdominal cavity, starting from the 5-6th day. In guinea pigs, a characteristic strong orchitis develops after several days and is accompanied by a febrile state and inflammation of the inguinal glands. Spirochetes are found in the blood in small amounts. Spirillum minus is also inoculated into monkeys, dogs, cats, rats, and some other animals. Spirocheticidal antibodies are found in the serum of patients and artificially infected laboratory animals. Rabbits and guinea pigs give a positive Wassermann and Meinicke reaction. There are no reliable methods for cultivating Spirillum minus. The main source of infection for humans are rats, spontaneously infected with Spirillum minus in a certain percentage (1-14%). Rat infection occurs exclusively through bites. The disease can also be transmitted through bites of ferrets, squirrels and other rodents, cats and dogs. S. is more often contracted by persons, by virtue of their profession or way of life, who come into closer contact with rats. Pathoanatomical changes are not very characteristic. An increased amount of fluid is noted in the cerebral ventricles, hyperemia of the meninges. Spirochetes were found in humans in the interstitial tissue of the testicle, in the cortical layer of the adrenal glands, in the kidneys between the tubules and in their lumen. At the site of the bite, there is a small-cell infiltration, mainly of the subcutaneous tissue-clusters of plasma cells and epithelioid elements. The clinical course in some respects shows a certain similarity with syphilis: primary lesion at the site of infection, enlargement of regional glands, rash. In addition to this similarity, S. sometimes gives a weakly positive RW, which quickly disappears after treatment with salvarsan. Mizoguchi (Mizoguchi) distinguishes the following forms of clinical course of S: 1) a form with predominance of local phenomena and rash, 2) a febrile form with rash all over the body, 3) a form with predominance of rheumatic pains at the beginning of the disease and transition to the 2nd form, 4) a form with predominance of nervous phenomena. There are also abortive forms. The febrile form is most often observed, characterized by a chronic course. The incubation period lasts on average about two weeks. The localization of the bite does not affect the duration of incubation. Usually the wound heals in a few days, sometimes the site of the bite itches. The onset of the disease is usually sudden. The temperature often rises with chills. The bitten place turns red, a clear infiltrate is outlined, sometimes a superficial ulceration develops, which can lead to necrosis. The primary lesion in S. sometimes has some similarity with the giant 'syphilitic chancre'. At the same time, the regional lymph glands become swollen (dense but not fused); a lymphangitis may also become apparent. Adjacent to the site of the bite, a maculo-papular rash appears on a larger or smaller area. The patient complains of general weakness, lassitude. In mild cases, the temperature drops after 2-3 days, and the local phenomena pass, and after 2-5 days a second rise in temperature may occur with exacerbation of the local process, and that's all. In more severe cases, the temperature at the first attack already rises to high figures, severe headaches appear, distant lymph glands swell. Symptoms of myocarditis are noted, slight enlargement of the spleen, sometimes vomiting and diarrhea, protein, red blood cells and cylinders may be found in the urine. Some cases are characterized by very severe muscle pains. The temperature lasts 2-5 days, falls critically. After a few days, the next attack occurs. Later on, either a typical alternation of attacks or an irregular remittent fever is observed. The rise in temperature is accompanied by an exacerbation of the phenomena at the site of the bite (see figure). As the attacks progress, the rash covers larger areas and may cover the entire trunk, face and limbs. In the interparietal periods, the rash usually completely disappears. The nature of the rash can be very diverse: papular, urticarial, measles-like and miliary. Edema of the legs and sometimes hair loss have also been noted. Anemia is observed in the blood. In the interparietal period, regenerative phenomena are noted on the part of the red blood cells. On the part of the white blood cells, during an attack, neutrophilia with a shift to the left and a decrease in eosinophils up to complete disappearance are noted. In the interparietal period, a slight eosinophilia may be observed. In most cases, the attacks cease after 2-3 months. Cases lasting up to a year and much longer (4 years and 20 years) have however been described. The most severe cases are characterized by severe nervous phenomena (paralysis), which can lead to death. As complications, corneal ulcer, iritis, jaundice and nephritis may develop. The mortality rate before the introduction of salvarsan therapy reached 10%. The diagnosis is made on the basis of blood examination for the presence of spirochetes and inoculation of animals. Differential diagnosis must be made with typhus, with malaria. Treatment. The specific remedies for S. are arsenobenzols. Intravenous infusions of neosalvarsan are recommended for an adult for the first time 0.3-0.45 and then another 2-3 doses of 0.45 with 5-7-day intervals. Children are given at the rate of 5 mg per 1 kg of weight. Already after the first infusion, the temperature drops to normal within a few hours, and all phenomena disappear very quickly. For prophylactic purposes, the place bitten by a rat must always be cauterized. Public prevention of S. consists in the fight against rats. In recent years, Spirillum minus has been artificially inoculated into progressive paralytics for therapeutic purposes by analogy with malaria inoculations. If one wishes to avoid local phenomena, it is necessary to carry out the infection intravenously, being careful not to get into the skin. In accordance with the condition of the patient, attacks are stopped at the right moment by neosalvarsan.

They often cease on their own. Experimental infection with S. should be tested in early forms of syphilis in view of the very interesting results obtained in the laboratory: if rabbits infected with syphilis are additionally infected with Spirillum minus, they soon become sterile with respect to Spirochaeta pallida (Takaki).