Akamushi

AKAMUSHI, Akamushi (synonyms: Japanese river fever, tsutsugamushi, kedani), a febrile disease transmitted through the bites of chigger larvae Trombicula akamushi, which in turn becomes infected from small rodents. This disease was first distinguished from the typhoid group of diseases in 1879 by Baltz and Kawakami, who observed this disease in the plains and along riverbanks in northern Japan. Later it was noted on the islands of Formosa and Sumatra, in the Yangtze Valley in China, in the Federated Malay States, and in Annam. In Japan, up to 3-4 thousand people annually contract A., mostly rural populations. All attempts to find the causative agent of this disease have so far remained unsuccessful. Only the following can be considered established: that the microbe-causative agent passes through ordinary filters. Among animals, besides rodents, macaques and gibbons are susceptible to infection. The carriers of this disease are the larvae of chiggers Trombicula akamushi and Trombicula deliensis. These larvae, besides humans, can attack dogs, cats, goats, and buffaloes, and especially rodents, from which they carry the infection to humans. Such a reservoir of the virus in Japan is Microtus montebelli, on the island of Formosa—the rat (Mus rattus rufescens), and in the Federated Malay States—domestic and field rats (Mus concolor and Mus diardii). The disease transmitter, Trombiculum akamushi, is a very small mite not exceeding 1 millimeter in length, light gray or red in color, externally resembling our mite Leptus autumnalis, which occurs on hemp. The Trombiculum akamushi larva reaches a maximum diameter of not more than 0.2mm, which makes finding it on the diseased person very difficult for detection. To find adult mites, it is recommended to collect the top layer of soil, shake it in water, and then the mites will float to the surface. Akamushi fever is a seasonal disease. The bite of the larva is not accompanied by pain and itching, and usually goes unnoticed. The larvae prefer to attach in areas covered with the thinnest skin, in the groin and armpit folds, on the scrotum. At the site of the bite, a reddish spot initially appears, which around the 3rd day turns into a vesicle up to 5 mm in size, on top of which a dark crust then appears (see Figure 1 and 2). 5-7 days after the bite, the first signs of the disease appear—swelling of the glands, increased temperature, conjunctivitis, and enlargement of the spleen. On the 5-6th day of the disease, a roseolar and roseolar-petechial rash appears (see Figure 3). From the blood side, at the beginning of the disease, leukopenia is observed, with the number of leukocytes falling to almost three thousand. Right from the start of the disease, nervous symptoms appear—marked excitability, headaches, insomnia, nightmares, and delirium. In favorable cases, the period of recovery begins in the third week. A past case of A. does not give complete immunity. According to some authors, the local population still has a significant degree of immunity, rarely contracts the disease and in mild form. Mortality from Akamushi fever in some epidemics (e.g., in Japan) reached up to 60% (Nogayo). - Treatment. There is still no specific treatment for akamushi. Some recommend early removal of the primary focus (site of the bite) by cauterization or excision (Hatori), which alleviates subsequent symptoms and sometimes completely stops the disease. To prevent mite attacks, it is recommended to smear the body with strongly smelling substances, such as lemon oil, sulfur ointment, or naphthalene paste. Good reports exist about a mixture of kaiput oil and tobacco juice. A more rational approach should be considered the thorough washing of the body and disinfection of clothing after agricultural work. If embedded mites are found on the skin, it is recommended to immediately cauterize or cut out that area: in this way, it is sometimes possible to prevent this disease. As for public prevention, in areas where there are many mites, it is recommended in early spring to clear small bushes and plow the soil deeply. At the same time, of course, it is necessary to carry out an energetic fight against the virus reservoirs—rodents, on which the mites parasitize.

E. Marcynowski. AKANTHOSIS (from Greek akantha—thorn, needle), acanthosis, is a peculiar change in the epidermis consisting mainly in hypertrophy of the spinous cell layer (str. spinosum), in the elongation and new formation of the inter-papillary epithelial complexes of the skin. A. is observed in many inflammatory and hyperplastic skin diseases, for example, in acanthosis nigricans (see).