[Pyrethroid resistance in human lice (Anoplura, Pediculidae): toxicological and molecular genetic methods].

The paper gives the data obtained in toxicological experiments versus analysis by a real-time polymerase chain reaction assay in permethrin-resistant human lice (VSSC1 gene kdr mutations leading to the amino acid replacements T9171 and L920F have been found). It is shown that the results of toxicological experiments may be indirectly indicative of the genetic composition of a study sample of lice.

[Peculicidal activity of plant essential oils and their based preparations].

The peculicidal activity of eight plant essential oils in 75% isopropyl alcohol was in vitro investigated. Of them, the substances that were most active against lice were tea tree (Melaleuca), eucalyptus, neem, citronella (Cymbopogon nardus), and clove (Syzygium aromaticum) oils; KT50 was not more than 3 minutes on average; KT95 was 4 minutes. After evaporating the solvent, only five (tea tree, cassia, clove, anise (Anisum vulgare), and Japanese star anise (Illicium anisatum) oils) of the eight test botanical substances were active against lice. At the same time, KT50 and KT95 showed 1.5-5-fold increases. Citronella and anise oils had incomplete ovicidal activity. Since the lice were permethrin-resistant, the efficacy of preparations based on essential oils was much higher than permethrin.

[Pyrethroid resistance mechanisms in the body lice Pediculus humanus humanus L.: detoxification enzyme systems].

Synergists (piperonyl butoxide, MGK-264 (N-octyl bicycloheptene dicarboximide), DEF (S, S, S, tributyl phosphorotrithioate), and diethylmaleate) were used to investigate the metabolic resistance of body lice to permethrin. Instances of the synergistic activity ofpermethrin when combined with enzyme system inhibitors have been identified. The synergic ratios were 3.3 to 52.0 for monooxygenase inhibitors; 5.2 to 7.4 for esterases, and about 4 for glutathione-S-transferases. Since the use of the synergists did not lead to full inhibition of resistance, it was concluded that the lice had also a kdr-like type of resistance.

[Current approaches to overcoming permethrin resistance in lice].

The paper gives information on pediculosis morbidity worldwide. It summarizes the data available in the literature on the resistance of head and clothes lice to pyrethroids and on the mechanisms of this resistance. The formation of head and clothes louse populations resistant to pyrethroids is shown to be a global problem. New groups of chemical substances that are alternatives to pyrethroids and the mechanisms of their action on lice are considered.

[Comparative activity of different groups of insecticides against permethrin-resistant lice (anoplura: pediculidae)].

The activity of insecticides (CK50, CK95 ) from different chemical classes against permethrin-resistant body and head lice was investigated. Having developed resistance to pyrethroids (permethrin, d-phenothrin, cypermethrin, and deltamethrin), the lice remain susceptible to organophosphorus compounds, phenylpyrazoles, neonicotinoids, and avermectins. The susceptibility of lice to the insecticides having a mechanism of action that is different from that of pyrethroids does not depend on the level of their resistance to permethrin.

[The systemic effects of imidacloprid and fipronil on Xenopsylla cheopis fleas (Siphonaptera) and blood-sucking Ornithonyssus bacoti gamasid mites (Gamasina: Macronyssidae)].

The systemic effects of imidacloprid and fipronil on Xenopsylla cheopis fleas and blood-sucking Ornithonyssus bacoti gamasid mites were studied under laboratory conditions. Albino rats were forcibly administered insectoacaricides per os in doses of 1, 10, 30 mg/kg or fed with dietary bait (the doses of fipronil and imidacloprid were 10-33 and 18-70 mg/kg/day, respectively) for 3 or more days. Fipronil had a pronounced systemic effect on both X. cheopis and O. baconi. Imidacloprid was markedly active against the fleas and, on the contrary, inactive against the mites.

[Resistance of the itch mites Sarcoptes scabiei De Geer, 1778 to scabicides].

The paper gives the data available in the literature on cases of the resistance of human itch mites to acaricides from different groups of chemicals. It considers major mechanisms for S. scabiei resistance to the scabicides commonly used in the world.

[Insecticide resistance in lice collected from homeless people in Moscow].

Permethrin and malathion resistance in body and head lice collected from homeless people in Moscow was investigated in March 2009 to March 2010. Most micropopulations were found to have permethrin-resistant individuals. Their proportion varied from 8.7 to 100%. Cross resistance of body lice to 5 insecticides (the pyrethroids permethrin, d-phenothrin, cypermethrin, deltamethrin, and the organic chlorine compound DDT) was revealed in one case. The lice remained susceptible to organic phosphorus insecticides (fenthion, malathion). The data on permethrin resistance in the lice, obtained by the standard method (immersion of the insects into an insecticide solution), correlated with those yielded by the modified WHO method.

[Mosquito complex (Diptera, Culicidae) in a West Nile fever focus in the Volgograd region. I. Species diversity and relative abundance in different habitats].

Potential West Nile virus (WNV) vectors were assessed during 2003 and 2004 at the indoor and outdoor collection sites of Volgograd and surrounding rural areas. A total of 26 387 female mosquitoes comprising 16 species in 5 genera of the subfamily Culicinae and 4 species of the subfamily Anophelinae were collected. The seasonal abundance and the dominance structure greatly differed in the multi-storied buildings, farms, and open habitats whereas the similarity of species diversity remained high throughout the season. In the porches of buildings, Aedes vexans (58%) and Cx. pipiens (37%) prevailed in early July (the beginning of a transmission period), Cx. pipiens (92%) was an absolute dominant species in August. The autogenous form of Cx. pipiens was most common in the flooded-basement houses of the city's outskirts. The number of anautogenous females in the indoor collections increased by August. Only the anautogenous form of Cx. pipiens was sampled in the open rural and urban areas. The findings suggest that the attraction of potential vectors, including anautogenous Cx. pipiens, from the outdoor biotopes to the porches of apartment houses is one of the main reasons for the spread of the disease in the urban population.

[Mosquito complex (Diptera, Culicidae) in a West Nile fever focus in the Volgograd Region. II. Host-feeding patterns of mosquitoes in different habitats].

Host preference of the mosquitoes collected in the urban and rural habitats of Volgograd and its suburbs was studied by the precipitation reaction test. Human and avian blood was detected in Cx. pipiens, Cx. modestus, Ae. vexans, Ae. behningi, Ae. caspius, Ae. sticticus, and females of the Anopheles maculipennis. The proportion of the mosquitoes fed on birds was similar in the urban and rural biotopes whereas that of the mosquitoes feeding on humans was significantly higher in Volgograd than in its environs. The increase in the number of human blood-fed mosquitoes in the city resulted mainly from the females collected in its multi-storied buildings.

[A complex of blood-sucking mosquitoes (Diptera, Culicidae) in the focus of West Nile fever in the Volgograd Region. III. Species feeding on birds and man and the rhythms of their nocturnal activity].

The rate and nocturnal rhythm of mosquito attacks of birds and human beings were studied in the open biotopes of Volgograd and its vicinity in 2004. Thirteen and 11 species of the subfamily Culicinae were collected under the Berezantsev bell and from the traps containing a chicken (a hen), respectively; of them 9 species were common. The mosquitoes of an Anopheles maculipennis complex were caught in a small portion to the traps of both types. Most species of Aedes were highly anthropophilic, showed the minimum activity at night and their abundance considerably decreased by the early transmission period. Among the species that were active during the transmission period, Ae. vexans, Coq. richiardii, and Cx. modestus more intensively attacked a human being than birds and Cx. pipiens was frequently attracted into the hen traps. The attraction of each species of the caught varied during the transmission period. The maximum attacks of Cx. modestus and Cx. pipiens on man and birds coincide and those of Coq. Richiardii and Cx. pipiens on man was observed earlier than on birds. A possible role of mosquitoes of different species in the epizootic and epidemiological processes is discussed.

[The gamasid mites (Parasitiformes: Mesostigmata) of small mammals from undeveloped land in Moscow]. / Gamazovye kleshchi (Parasitiformes: Mesostigmata) melkikh mlekopitaiushchikh nezastroennoi territorii Moskvy.

On 11 species of small mammals collected in the parks and ruderal areas of Moscow in 1964-1991, 35 species of mites were revealed. Among them 23 species were parasitic. Laelaps hilaris, Haemogamasus nidi, and Androlaelaps glasgowi were predominant. The mite species diversity on small mammals in Moscow is similar to that in natural environments. The epidemiological and epizootiological significance of revealed species of mites is discussed. The rat mite Ornithonyssus bacoti has the major medical importance as the pathogen of the rat mite dermatitis in Moscow and as a vector of transmissive diseases. According to literature and the data obtained the favorable conditions for maintenance of transmissive diseases reservoirs exist permanently in Moscow.

[The study of mosquito fauna (Diptera, Culicidae) in Volgograd city in light of the outbreak of West Nile fever in Volgograd region, 1999]. / Izuchenie fauny krovososushchikh komarov (Diptera,Culicidae) g.Volgograda v sviazi so vspyshkoi likhoradki Zapadnogo Nila v Volgogradskoi oblasti v 1999 g.

Mosquito sampling was carried out in Volgograd city and its vicinity in August 2001 and 2002. In total 16,000 individuals belonging to 6 genera and 12 species were collected. Nine species were anthropophilic. Culex modestus and Aedes vexans dominated in all outdoor samples collected in Volgograd city. In addition to these species, Coquillettidia richiardii and Ae. caspius were abundant in the vicinity of Volgograd. Autogenous Cx. popiens dominated among six species sampled indoors in Volgograd city. The possible role of different mosquito species in West Nile virus circulation in Volgograd city is discussed.

[Foci of the rat mite Ornithonyssus bacoti (Mesostigmata, Macronyssidae) and rat-mite dermatitis in Moscow]. / Ochagi krysinogo kleshcha Ornithonyssus bacoti (Mesostigmata, Macronyssidae) i kleshchevoi dermatit v Moskve.

High density of the rat population in Moscow in 1990-1991 resulted in the appearance of Ornithonyssus bacoti foci and of cases of the rat-mite dermatitis in humans. A total of 36 foci of the disease were examined and eradicated. A method for the detection of such foci has been developed. Two types of foci are distinguished, communal and industrial, and their specific features as regards the rodent and mite populations and clinical features of dermatitis in humans are described. A system of measures for liquidation of foci of rat mites is suggested, including rat and mite eradication and treatment of the patients. Specific features of these measures for various types of foci and in case of a focus reappearance are enumerated.

[An experimental study of the capacity of the rat mite Ornithonyssus bacoti (Hirst, 1913) to ingest, maintain and transmit Borrelia]. / Eksperimental'noe izuchenie sposobnosti krysinogo kleshcha Ornithonyssus bacoti (Hirst, 1913) vosprinimat', sokhraniat' i peredavat' borrelii.

For the first time a possibility of the gamasina mites' O. bacoti participation in Lyme disease spirochetes' circulation has been demonstrated. It has been experimentally shown that Borrelia burgdorferi s.l. are received by O. bacoti, survive in them for at least 21 days and are transmitted to white mice through mites' bites. Mice's infestation has occurred in 23% of cases. It is suggested that other bloodsucking gamasina mites inhabiting the Lyme borreliosis reservoir rodents nests may be capable of participating in borrelia circulation in the Lyme disease endemic areas.