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R L Naumov

Publications and source records attributed to R L Naumov.

At least 19 recordsLinked to original sources
PubMedDate not supplied

[A new generation of acaricide--attractant acaricidal granules].

The paper gives a brief account of the earlier results of papers with the development of attractive acaricidal granules (AAGs) and the results of their field tests in Tyumen Province and Krasnoyarsk Territory. AAGs in combination with sumithion yielded the best results than those with permethrin: their efficacy was over 90% and their action lasted 1.5 months.

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PubMedDate not supplied

[The results of a study of the acaricidal activity of the preparation Fewry-med].

The acaricidal activity of Fewry-med (10% zeta-zipermethrin) against Ixodes persulcatus was studied in laboratory and field conditions. The drug's doses of 0.01-0.005 g/m2 (as calculated for active ingredient) provided 100% death of ticks when forest areas (Tyumen' Province) were treated. The efficiency of treatment preserved within 31 days (the follow-up period). When Fewry-med was used in a dose of 0.005 and 0.01 g/m2, the soil levels of zeta-zipermethrin was lower than the maximum allowable concentration at days 7 and 14 after treatment. In the treated areas, the size of crawling representatives of the entomofauna restored at day 25. The drug may be recommended for industrial trials.

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PubMedDate not supplied

[An experimental study of the capacity of the rat mite Ornithonyssus bacoti (Hirst, 1913) to ingest, maintain and transmit Borrelia].

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.

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PubMedDate not supplied

[The exploratory activity of the Borrelia-infected taiga tick Ixodes persulcatus].

The infection with Borrelia burgdorferi s. l. increases the questing activity of adults and nymphs of the taiga tick Ixodes persulcatus. High temperature inhibits the moving and questing activities of the infected ticks in a greater extent than that in the non-infected ones. Than more borreliae per a specimen of tick are present, the more tick's activity is affected.

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[Borrelia burgdorferi s.s. length and its variability].

The length of 469 Borreliae burgdorferi s.I. from the Ixodes ricinus and I. persulcatus images collected in the Moscow Region, that of 5433 B. burgdorferi s.s from the I. persulcatus nymphs and images cultured at a laboratory, and B. burdorferi s.s. grown on the BSK-II (1 and 10 passages) were measured. There was a wide range of variations in the length of specimens (3-74 microns) and in those of this group average sizes (10.7-24.8 microns). The lengths of Borelliae from natural and laboratory ticks after their molt were 17-18 microns. When the ticks were kept in the refrigerator as long as 1-2 years, the length of Borreliae decreased to 10.7-10.9 microns, upon multiple (10) passages on the BSK-II medium, their lengths increased to 24.8 microns (the differences being significant). When the length of Borreliae reduced due to their keeping in the refrigerator, their pathogenicity for albino mice diminished. This disappeared after multiple BSK-II medium passages. It is suggested that the length of Borreliae may serve as a marker of their pathogenicity.

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PubMedDate not supplied

[A laboratory model of the parasitic system of Lyme disease].

A laboratory model of the parasitic system of Lyme borreliosis (LB) with Ixodes persulcatus and Borrelia burgdorferi s.s. underwent 5 epizootic cycles (Cycle I transition of Borreliae by the scheme a tick-->a mouse-->a tick corresponds to the seasonal cycle). A group of 5-6 mice was inoculated with the suspension of infected nymphs by the intracutaneously route and 35-45 days later intact tick larvae or nymphs were fed on them. In the first three cycles, 40-100% of mice in a group (a total of 33 of 59) were susceptible, but 3 of 11 groups of mice were not inoculated. 20-50% of larvae and 75-92% of nymphs were susceptible on the infected mice. The mean geometric abundance of borreliae was 2.8-6.3 cells per 100 fields of vision in the nymphs infected in the larval phase and 16.1-29.5 cells in the image phase. In cycle IV, 2 of 6 groups of mice were unsusceptible to borreliae and 5 of the 17 mice from 4 groups got infected. One mouse died from Lyme borreliosis when larvae were fed on it. The nymphs remolted from underfed larvae were infected in 62.2% of cases, the mean geometric abundance in these nymphs was 5.7% per 100 fields of vision. A total of 3.2-14.7% of the ticks fed on the remaining 4 mice were infected and the abundance of boreliae was 1-2 per 100 fields of vision. In cycle V, one of 12 mice got infected, the infection rate in nymphs was 9.1%, the abundance of borreliae was 1 per 100 fields of vision. Thus, as the number of epizootic cycles increases, the proportion of infected mice, that of ticks infected on these mice on feeding, and the abundance of borreliae in the infected ticks decrease. Moreover, there was a reduction in the length of borreliae reduced from 17-18 mm to 10-11 mm and in the duration of multiplication and preservation of borreliae in the infected ticks and there was concurrently an increase in the duration of development of an infectious process in mice. It is suggested that the population of borreliae consists of 2 morphophysiological groups or more. During cultivation of the laboratory model of the parasitic system of Lyme borreliosis, a group of borrelia that are short and slightly pathogenic for mice had got many points in its favour. A five-fold procedure of artificial election of precisely defining this group set the model on the verge of disappearance. The capacity of the populations of borreliae to alter their properties rapidly and fundamentally suggests that there might be violent annual fluctuations in human morbidity.

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PubMedDate not supplied

[Mixed infection in ticks: a rule or an exception?].

A hypothesis for the independence of acts of infection in ticks with pathogens from each other in mixed infection has been tested on the basis of the data available in the literature. In most cases the number of ticks with mixed infection is consistent with the independence hypothesis and fails to reinforce the statement that there is antagonism of pathogens. But in some reports the number of mixed-infected ticks is 3-13 times higher than the calculated number according to the accepted hypothesis. These facts suggest that the natural tolerance of ticks to pathogens due to primary infection may be reduced. Other possible reasons for differences in the actual and calculated number of mixed infected ticks are also discussed.

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PubMedDate not supplied

[The attraction of taiga ticks by the smell of the host's fur in nature].

In the "Zhigulevsky" preserve, 46 coarse calico napkins impregnated with 1 ml of an attractant, were placed alternatively as controls and experimental along the road with the interval of 5 meters. The attractant was a methanol wash-off of the hair of a mongrel dog. During 8 hour exposure the experimental napkins were attacked by 20% males and 12.5% females of active ticks living by the road (after the third experiment a complete catch of ticks was carried out). The tick distribution indirectly indicates that the attractant causes a increase of tick horizontal migrations up to 5 meters around the source of odour. The results obtained allow one to suggest a promising granulated attractive and acaricidal agent.

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PubMedDate not supplied

[Longevity of forest and taiga ticks (Ixodidae) infected and non-infected with Borrelia burgdorferi groups].

A life longevity of Ixodes ricinus and I. persulcatus have been examined in laboratory conditions. It was found that specimens infected with borreliae live slightly longer than non-infected ones (difference is not reliable); females live 1.5 times longer than males; I. ricinus lives 2-4 times longer than I. persulcatus. It is suggested that I. persulcatus has a higher rate of metabolism than I. ricinus and that the latter species obtains an ability to survive after the last moult two winters and keep an activity in two summer seasons not counting the year of moulting.

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[The affection of the population with Borrelia and the incidence of Lyme disease].

The proportion of Lyme borreliosis seropositive residents in a number of Russia is 1-2 thousand times greater than that of officially notified patients. It is suggested that due to the ability of Lyme borreliosis to manifest in the late periods after infection, the time and chronicity of the infection, the number of officially recorded patients may significantly increase due to the manifestation of the disease in seropositive apparently healthy (at the moment of an examination) dwellers. There is evidence for that it is expedient to follow up seropositive residents and tick-bitten individuals.

Antibodies, Bacterial↗
PubMedDate not supplied

[The longevity of the tick Ixodes ricinus (Acari: Ixodidae) in Central Russia].

The longevity of the tick Ixodes ricinus has been studied on 27 samples from a wild population of the Moscow Region. Ticks were kept in small cages and glass tubes under conditions close to natural. About 2/3 of the specimens collected in spring survived till the next spring and later died out gradually during the second season of their activity. Very few specimens reached the beginning of the third winter in their life, but apparently none of them survived the end of the winter. The life span of males was the same as that of females. No mass activation of adult ticks was recorded in the autumn of the year of their molting. It seems that the rise of the autumnal density of adult ticks depends mainly on the increased activity of the females which molted from nymphs last year.

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PubMedDate not supplied

[Methods for suppressing the population count of pasture ixodid ticks].

The current methods of suppressing the quantity of Ixodes ticks in pasture populations are reviewed. For one- and two-host monoxenous [correction of monogostal] species the methods used were treatment of ticks during their parasitic existence on the cattle (washing in baths, spraying with acaricides, use of ear marks and collars, soaking with acaricides, selection of tick-resistant cattle species, administration of avermectins to the host) and separation of cattle and ticks by changing pastures. For two- and three-host polyxenous [correction of polxgostal] tick species the methods used were treatment of the affected area with acaricides (in the USSR anti-tick area treatments have been practically stopped), separation of cattle and ticks (pasture of cattle on cultural pastures, keeping the cattle in stables), changes of ecological conditions of tick habitation.

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