[(THE CURRENT SITUATION OF DIPHYLLOBOTHRIASIS: EPIDEMIOLOGY AND EPIDEMIOLOGICAL SURVEILLANCE)].

The paper analyzes the etiology of diphyllobothriasis pathogens and their distribution in the world. It estimates the infection rate of the population with tapeworms, the value of different fish species and procedures for their cooking as factors for transmission of Diphyllobothrium to the population and the risk for infection with tapeworms through infected foods. Epidemiological surveillance measures in different (synanthropic and natural) foci of diphyllobothriasis and with various types of pathogens are considered.

[Assessment of Nanophyetus salmincola schikhobalowl (Skrjiabin et Podjiapolskaja, 1931) infestation of salmonlike fishes in the rivers of the Khabarovsk Territory].

Parasitological investigations of 529 specimens of 7 fish species from the water basins of the Khabarovsk Territory in 2009-2013 revealed the high extensity (11.7 to 100%) and intensity (as many as 9341 larvae per fish) of invasion with N. s. schikhobalowi metacercaria in salmonlike fishes from the mountain tributaries (Khor, Anyui, and Manoma) of the Amur river. The examined specimens of four salmonlike fish species (Thymallus tugarinae, Hucho taimen, Brachymystax tumensis and B. lenok) showed an increase in all indicators of infestation: invasion extensity (IE), invasion intensity (II), and abundance index (AI) with age. Moreover, IE peaked just in a 3-4-year-old fish (and in 1-year-old B. lenok) and further remained virtually unchanged. N. s. schikhobalowi metacercaria accumulated in the fish trunk with age, by maintaining their viability. With very high II, practically 100% infestation in B. lenok makes the population run the maximum risk of Nanophyetus infection with the dietary intake of this fish species if it is not disinfected. Examination of the distribution of N. s. schikhobalowi metacercaria in the trunk of Thymallus tugarinae showed that over 50% of larvae were detectable in the kidneys. This peculiarity of their localization could propose a simple method to determine II for Nanophyetus larvae in salmonlike fishes. Recommendations for reducing the risk of human infection with trematodes are given.

[A local case of acute opisthorchiasis in the Moscow Region].

The paper describes a case of acute opisthorchiasis in a 31-year-old female patient after ingestion of dried fish of the family Cyprinidae caught in the Oka River basin on the border of the Moscow and Ryazan Regions. This case could convince of that there was a risk of human Opisthorchis infection despite the zoonotic pattern of circulation of the pathogen in European Russia. The dietary intake of unsterilized fish of the family Cyprinidae caught in the Moscow and neighboring regions may give rise to Opisthorchis invasion and, it a large infectious dose, to acute opisthorchiasis.

[Extraenteric infection caused by Blastocystis spp. in a female patient with liver abscess].

The cases associated with the development of liver abscesses in a 64-year-old female patient after elective surgery for colon polyposis could form an opinion that extraenteric infection caused by Blastocystis spp. might develop in the immunocompromised host. The development of Blastocystis spp. in the presence of disintegrated liver tissue and inflammatory cells was verified by microscopic examination of liver abscess aspirates. The Romanovsky-Giemsa stained specimens exhibited typical amoeboid, vacuolar and, what is particularly important, dividing forms of Blastocystis spp. The patients full recovery after timely combination therapy with broad-spectrum antibiotics and imidazole group preparations also indirectly argues for the etiological role of Blastocystis spp. in the development of liver abscess with the signs of changes in both lungs (the signs of right lung compression and bilateral hydrothorax). Physicians' awareness of the potential clinical significance of Blastocystis spp. in immunodeficient patients is sure to expand the range of differential diagnostic studies of patients infected with Blastocystis spp.. particularly in case of gastrointestinal tract diseases of unknown etiology.

[Social bases for the functioning of nanophyetiasis foci in the Amur region].

Parasitological examination of the population of the Amur Region has revealed that the nanophyetiasis foci affecting as high as 28.4% of the people are being preserved and functioning now; at the same time the highest rates of infection with the trematode Nanophyetus salmincola schikhobalowi are seen in the dwellers of the populated areas situated on the banks of the mountain Amur tributaries. It has been ascertained that the major season when the population is infected with Nanophyetus is summer and its highest incidence are noted in autumn (November) after the active fishing season is completed. It has been found that infection occurs in infants and the maximum incidence is in the age group of 21-30 years (45.5%) and remains virtually the same in a middle-aged population [31-50 years (37.0-42.2%)], by decreasing slightly in the older age groups (18.2-21.7%). According to the questionnaire survey data, fish (90% of its species are an intermediate host for Nanophyetus) is a staple food in the population of the highest incidence rural areas. The major causes of Nanophyetus infection are the wide consumption of raw and low-salt fish and a low population awareness of measures to prevent helminthiasis, the transmission factor of which is fish.

[Tourism, imported parasitic diseases, and their prevention].

The paper gives the results of observations of 1558 patients before and after tourist travels to tropical countries and 368 individuals visiting the north areas of the Russian Federation. Different conditions (malaria, amebiasis, leishmaniasis, intestinal and tissue helminthiasis, insect bites, venomous fish pricks, medusa burn, tick bites, etc.) were found in 402 persons. Prophylactic immunization included vaccination against hepatitis A and B viruses, meningitis, typhus, yellow fever, tick-borne encephalitis in more than 2500 patients (not including influenza vaccination in the epidemic season). The performed observations reinforce the statement that imported pathology is urgent to Russia and suggest that it is necessary to develop this section of medicine and to set up a network of health care facilities with a necessary therapeutic and diagnostic base to render skilled care to tourists. It is essential to improve medical staff training in travel medicine.

[Effect of the hybridization of Schistosoma mansoni strains on the degree of compatibility of the parthenitae with their mollusk intermediate hosts]. / Vliianie gibridizatsii shtammov Schistosoma mansoni na stepen' sovmestimosti partenit s molliuskami--promezhutochnymi khoziaevami.

After-effects of hybridization of S. mansoni strains, having Biomphalaria pfeifferi as an intermediate host, have been revealed for the first time. The crossing of two african strains (malarial-M and guinea-G), which have different compatibility rates with their specific intermediate hosts, has shown that hybrids display a higher virulence in respect to molluscs-hosts than maternal strains. The compatibility rate of the first generation hybrids with B. pfeifferi decreased, the breachs in the compatibility being the more significant the higher the degree of adaptation between the maternal strain and specific intermediate host. The infectiousness of the second generation hybrids in respect to molluscs of two populations of B. pfeifferi (M and G) virtually did not differ and varied in the ranges of mean values between the initial infectiousness of two maternal strains.

[Laboratory animal infection in modeling intestinal schistosomiasis]. / Zarazhenie laboratornykh zhivotnykh pri modelirovanii kishechnogo shistozomoza.

A comparative efficiency of different regimes for infecting laboratory animals has been determined in order to find out optimal conditions under which an experimental model of intestinal schistosomiasis (infection with Schistosoma mansoni) can be maintained. When evaluating the results of laboratory definitive hosts infection we took into account the character of Schistosoma distribution in animals, which with high probability rate was modelled by means of negative binomial distribution. The main parameters of this distribution were used for determination of effective doses and methods of animals infection alongside with generally accepted indices of infection rate and intensiveness. Analysis of the data obtained has shown that the infection of 150 cercarians per mouse and 200 cercarians per golden and striped hairy-footed hamster by their subcutaneous administration creates optimal density of parasites in the host. Results of investigations have shown that striped hairy-footed hamsters can be used as definitive hosts of Schistosoma.

[Method for the individual maintenance of mollusks infected with Schistosoma larvae in a thermostatic apparatus]. / Metodika individual'nogo soderzhaniia molliuskov, invazirovannykh lichinkami shistosom, v usloviiakh termostatirovaniia.

A technique has been suggested for individual maintenance of intermediate hosts of Schistosoma mansoni, molluscs of the genus Biomphalaria, in thermostat water bath with thermoregulator in order to study the host-parasite relationships in the mollusc-trematode system. Advantages of the suggested technique have been shown for studying total production of Cercaria when estimating the compatibility degree of various strains of S. mansoni and races of molluscs of some species of the genus Biomphalaria.

[Comparative efficiency of infecting laboratory animals via intravenous and subcutaneous administration of Schistosoma mansoni cercaria]. / Sravnitel'naia éffektivnost' zarazheniia laboratornykh zhivotnykh pri vnutrivennom i podkozhnom vvedenii tserkarii Schistosoma mansoni.

Comparative study on effectiveness of intravenous and subcutaneous methods of infection of animals has shown that infection rate of helminths after the injection of equal dozes of cercariae under skin, into portal and femoral veins of golden hamsters does not differ significantly (42.6 +/- 4.2, 37.8 +/- 5.8 and 26.0 +/- 6.6 schistosomes, respectively). When using the above methods for cotton rats the infection rate was lower than that in golden hamsters. The most insignificant infection rate of parasites was recorded in both species after the injection of cercariae into the femoral vein. Results of the infection of golden hamsters with different dozes of cercariae have shown that with the increase of dozes of infectious material the infection rate of helminths rises during the experimental intestinal schistosomiasis only to a definite level, which is attained by the injection of cercariae into the portal vein in dozes lower than those used for subcutaneous infection.

[The structure of the nosogeographic range of opisthorchiasis in the Ob-Irtysh basin]. / Struktura nozoareala opistorkhoza v Ob'-Irtyshskom basseine.

Results of our own investigations and available data in the literature concerning the epidemiology of opisthorchiasis in Ob-Irtysh river basin have been gathered, and geographic ranging have been established. The prevalence of infection, children's infection rate, the intensity of infection and clinical manifestation rate have been suggested as a criterion for division of territories into areas. 4 degrees of endemia was established: areas with sporadic incidence rate (prevalence is less than 1%); hyperendemic (prevalence 1-10%, intensity of infection 1-20 egg/gr., children's infection and clinical manifestation are absent), mesoendemic (prevalence 10-40%, children's infection rate 1-25%, intensity of infection about 300 egg/gr., clinical manifestation rate about 50%) and hyperendemic area (prevalence above 40%, children's infection rate 25-60%, intensity of infection above 300 egg/gr., clinical manifestation rate about 80%). Original map of pattern of opisthorchiasis distribution area is presented. The decreasing of transmission of O. felineus to periphery of basin is noted.

[The characteristics of the circulation of the causative agent of opisthorchiasis in the tributaries of the Ob]. / Osobennosti tsirkuliatsii vozbuditelia opistorkhoza na pritokakh Obi.

Opisthorchiasis morbidity is reviewed in the area of the Vasyugan River, an Ob tributary. Intermediate hosts have been found in 3 settlements situated at various distances from the ostium. The infestation of intermediate and additional hosts with Opisthorchis larvae is investigated. The above data and the results of previous population surveys (establishing infestation and contamination) served the basis for elucidating the nature of helminth circulation on the territory along the Vasyugan River. The role of infected fish migration is discussed as a source of human infection in areas where helminth circulation is altogether absent or is at an extremely low level.

[The prognosis of the diphyllobothriasis situation in water reservoirs under construction (the Adyche and Sakhalin reservoirs)]. / Prognozirovanie situatsii po difillobotriozom na proektiruemykh vodokhranilishchakh (Adychanskoe i Sakhalinskoe).

The investigations conducted in the construction area of Adyche and Sakhalin water reservoirs made it possible to work out the prognosis for the changes in the situation on diphyllobothriasis. In the area of Adyche water reservoir the population invasion with D. latum is likely to increase, while in the area of Sakhalin water reservoir the situation on D. klebanovskii sp. no. will remain unchanged.

[The procedure for the wide use of praziquantel in a complex of measures to control opisthorchiasis. 1. The tolerance and efficacy of different doses of biltricide during outpatient use in foci]. / Taktika shirokogo primeneniia prazikvantelia v komplekse mer bor'by s opistorkhozom. Soobshchenie 1. Perenosimost' i éffektivnost' razlichnykh doz biltritsida pri ambulatornom primenenii v ochagakh.

The results of wide uses of praziquantel (bilthricide, Bayer, Merck) to treat 2,440 persons in the outpatient setting of the endemic foci of opisthorchiasis in Tomsk Province suggest that the agent is highly effective (on the average of 97%) and well tolerable. There are no great differences in the efficiency of treatment, the frequency and magnitude of adverse reactions during out- and inpatient treatments. There are no either basic differences in the efficacy of praziquantel doses of 30, 40, and 60 mg used in the treatment of patients with Opisthorchis infection in whom 1 to 1.00 eggs per g feces are found. The use of praziquantel in a daily dose of 30 or 40 mg/kg in the outpatient setting permits the mass drug therapy of the population in the endemic foci, by reducing expenses on treatment. It is advisable to continue investigations of praziquantel used in small doses among the populations at low infection risk.

[The epidemiological efficacy of opisthorchiasis control measures in Dnieper River basin foci]. / Epidemiologicheskaia éffektivnost' protivoopistorkhoznykh meropriiatii v ochagakh bacceina Dnepra.

The authors assess the epidemiologic efficacy of wide-scale antiopisthorchiasis measures taken in the basin of the Dnepr River in 1984-1990. The structure of the population morbidity and the time course of this morbidity under the effect of a complex of measures taken were analyzed in low-, medium, and highly-endemic foci of the disease. Hygienic education and adequate detection and treatment of the invaded subjects were found to be the principal factors contributing to sanitation of the population. These measures are the most effective in subjects aged under 40, in whom the share of cured subjects is the highest and reinvasions are the least frequent. Health education detection and chloxyl treatment of the patients helped reduce more than twofold the disease incidence over 5 years even in highly endemic foci and permitted complete sanitation of the children.

[The procedure for the wide use of praziquantel in a complex of measures to control opisthorchiasis. 2. The tolerance and efficacy of Russian-made azinox in mass treatment in foci]. / Taktika shirokogo primeneniia prazikvantelia v komplekse mer bor'by s opistorkhozom. Soobshchenie 2. Perenosimost' i éffektivnost' azinoksa otechestvennogo proizvodstva pri massovom lechenii v ochagakh.

Whether the Russian praziquantel analog azinox can be widely used in the foci of opisthorchiasis was first assessed. The outpatient treatment of 7405 patients with the agent in doses of 30, 40, 60 mg/kg body weight revealed that azinox tolerance did not depend upon the intensity and degree of clinical infection signs but it was slightly worse when a dose of 60 mg/kg was given. Children virtually showed no adverse reactions, in adults their frequency was no more than 52 +/- 1.4%. The parasitological efficiency of azinox in the used doses was 96-99% in children and 82-86% in adults. There was a clinical improvement in 65% of the treated. Thus, the national drug azinox is not inferior to the imported agent bilthricide in tolerance, parasitological and clinical efficiency. Bearing in mind the equal efficiency, but the better tolerance and less cost of the drug doses of 30 and 40 mg/kg body weight, it is advisable to use them in the foci for outpatient treatment.