[(HUMAN DIROFILARIASIS: CLINICAL DIAGNOSTIC FEATURES ASSOCIATED WITH DIFFERENT DEVELOPMENTAL STAGES OF THE PATHOGEN)].

To seek medical advice is due to the time when a person has become infected during the infection transmission season (July-August) and the duration of development of the pathogen Dirofilaria (N.) repens in his/her body Clinical manifes- tations occurred in 61% of the patients 6-10 months after infection, as confirmed by the maximum body sizes (125-160 mm) of removed females which have reached puberty. PCR-based diagnosis in conjunction with microscopic studies improves the efficiency of identifying the patients and the species of the pathogens D.repens and D.immitis. The use of these methods for the first time in 2016 could confirm D.immitis infestation in a 14-month-old infant living in the Solnechnogorsk District, Moscow Region.

[(INTRODUCTION OF RESEARCH RESULTS INTO THE TRAINING OF PHYSICIANS IN THE SPECIALTY OF PARASITOLOGY)].

The paper presents the results of theoretical and practical studies into parasitology, which were conducted at the E.I.Martsinovsky Institute of Medical Parasitology, Tropical and Vector-Borne Diseases and then used for the training of specialists with higher medical education at the Department of Tropical Medicine and Parasitic Diseases, I.M.Sechenov First Moscow State Medical University. The need to develop professional skills is related to the increasing learning require- ments due to socioeconomic conditions and the epidemiological situation in the country.

[(THE FAUNA OF BLOODSUCKING MOSQUITOES IN THE NIZHNY NOVGOROD REGION, THEIR INFECTION WITH DIROFILARIA AND ENDOSYMBIOTIC BACTERIA)].

The fauna of bloodsucking mosquitoes in the Nizhny Novgorod Region is represented by 11 species from 5 genera of the family Culicidae. During 2014-2015, the predominant species were Ochlerotatus cantans and Aedes cinereus mosqui- toes in both a population aggregate and woodland. The infected mosquitoes accounted for 1.3% of their total number and were registered only in the village of Fokino. The investigators identified two human pathogenic nematode species: Diro- filaria immits and Dirofilaria repens (0.9% and 0.4% respectively). The effective carriers of Dirofilaria in the examined area can be Ae.cinereus and Och.cantans as only these species were found to have an invasive stage of the parasite. The symbiotic bacterium Wolbachia was detected in the mosquitoes that were not infected with dirofilariasis. This is the first study in Russia to investigate the effects of Wolbachia on the susceptibility of dirofilariasis vectors to infection.

[CURRENT IDEAS ON OBLIGATE AND FACULTATIVE RELATIONSHIPS BETWEEN MAN AND THE DIROFILARIASIS PATHOGEN DIROFILARIA (N.) REPENS].

The ability of D. repens to complete its ontogenesis in man points to their obligate, rather than facultative rela- tionships. The fact that microfilariae are rarely found in human blood or are absent there may be associated with the removal of developing dirofilariae from humans in earlier than they achieve sexual maturity. Facultative ecological relationships to mosquitoes may be one of the reasons for limitation of human invasion cases. However, in long-standing microfilaremia in man (an obligate host), D.repens may take part in the epidemiological chain of dirofilariasis as a source of invasion.

DIROFILARIASIS: CURRENT ASPECTS OF STUDIES.

The review touches upon the main directions and some of the most important results of an investigation of dirofilariasis the species of the genus Dirofilaria, their spread, and hosts. It describes cases of human infection with Candidatus Dirofilaria hongkongensis, a study of the prevalence of filariasis using a geographic information system, data on the contamination of Dirofilaria in Europe, and current views on the endosymbiotic relations of Dirofilaria with the Wolbachia bacterium.

[CLINICAL CASE OF DIROFILARIASIS.]

The paper describes a case of the rare localization of a pregnant Dirofilaria female in a man's genitalia. Patient T born in 1973 was infected in the Krasnoyarsk Territory presumably in the summer of 2012. A migratory mass appeared under the skin of the chest at the beginning of 2016. A dense mass was located beneath the skin in the penis by early April. Histological specimens from the removed tumor, entered the specialized Clinical Diagnostic Laboratory for parasitic diseases. The specimens exhibited transverse and oblique sections of Dirofilaria spp. The body cavity contained nematodes - multiple microfilariae. However, routine studies and PCR could not reveal the microfilariae in the blood.

[Human dirofilariasis: clinical and diagnostic signs and diagnostic methods].

The clinical and diagnostic signs caused by the tissue location and migration of adult Dirofilaria in the human body determine the use of different methods for the diagnosis of dirofilariasis. During their investigations, the authors modified polymerase chain reaction (PCR): they chose and synthesized primers and selected amplification regimens for them and obtained agarose gel bands that corresponded to PCR fragment length nucleotide sequences that were equal to 245 bp for D. (N.) repens and 656 bp for D. immitis. There was 100% agreement in the results of PCR and microscopic examination of sera from 32 dogs and 1 female patient with low parasitemia and in the blood nucleotide sequence characteristic of D. repens.

[Results of studies of human dirofilariasis in Russia].

Human dirofilariasis is a pressing health problem in Russia. By 2014, there have been as many as 850 Dirofilaria repens-infested people living in 42 subjects of the Russian Federation. One of the favorable factors for circulation and spread of invasion is a temperature of above +20-24 degrees C; when the latter is maintained during at least 20 days there may be 1.-1.5 circulations of invasion in the carrier and a 2.8-fold increase in transmission intensity. The border ofa dirofilariasis area with a temperate climate is southward to 58 degrees N in European Russia and West Siberia and southward to 50 degrees N in the Far East. The conditions in the human body have been found to be more favorable for the development of Dirofilaria than considered before and allow the helminth to achieve sexual maturity and to propagate. If man has microfilaremia, he may be a source of invasion. It is necessary to examine venous blood by the enrichment method and, if possible, polymerase chain reaction and enzyme immunoassay, which make it possible to establish a diagnosis in occult invasion and to identify a pathogen species.

[Entomological monitoring of an area to assess Dirofilaria transmission risk].

As the basis for entomological monitoring, the authors first propose to investigate the structure of a season of D. repens invasion transmission in the carrier in relation to the ambient temperature, such as onset of a transmission season, terminaton of mosquito infection, the number of invasion circulations. A calculating procedure has been developed. It is shown that there is a need for entomological monitoring of each specific area irrespective of the latitude to study a risk for local dirofilariasis cases.

[Dirofilariasis in the Moscow Region, a low disease transmission risk area].

The spread of canine and human dirofilariasis was first studied in the Moscow Region, a low disease transmission risk area. D.repens infestation was found to have a tendency to increase in Moscow residents with the imported cases being predominant. In 33 (84.6%) districts of the Moscow Region, dogs were registered to have D. immitis and D. repens infestation, with the former being preponderant in 31 districts. An original map of dirofilariasis distribution was compiled with the areas being singled out at a distance of Moscow: 15-20 km (6 districts) (the first ring); as long as 70 km (11 districts) (the second ring), and over 70 km (16 districts) where infestation rates greatly varied in both the number of infected animals and human beings and the species of causative agents.