PubMed Health⌕ Search

Biomedical subjects

B Gilot

Publications and source records attributed to B Gilot.

At least 19 recordsLinked to original sources
PubMed2003

Prevalence of Borrelia burgdorferi species and identification of Borrelia valaisiana in questing Ixodes ricinus in the Lyon region of France as determined by polymerase chain reaction-restriction fragment length polymorphism.

Many cases of Lyme borreliosis have been reported over the years in the region of Lyon, France. The identification and prevalence of Borrelia burgdorferi sensu lato in Ixodes ricinus were investigated by polymerase chain reaction (PCR) of the flagellin gene and restriction fragment length polymorphism (RFLP) analysis. Questing Ixodes ricinus larvae, nymphs and adults were collected by the flagging method from deciduous forests in four areas in the Lyon region of France between October 1994 and September 1995 and in June 1998. The overall prevalence of Borrelia burgdorferi sensu lato was 13.2% (91/688). No significant differences in prevalence were observed between the different stages and sex of the ixodids or between collection areas. The majority of infections were simple infections (82.4%; 75/91), most of which were due to Borrelia afzelii (41.4%), while coinfections (12.1%) were predominantly (54.5%) a combination of Borrelia valaisiana and Borrelia garinii. No tick was infected with more than two borrelial species, nor was Borrelia lusitaniae identified. The Borrelia valaisiana species was detected for the first time in France, confirming its widespread presence in Europe. This study confirms that the surroundings of Lyon are risk areas for contracting Lyme disease and that no particular clinical manifestations predominate due to the heterogeneous distribution of Borrelia genospecies. Moreover, the polymerase chain reaction restriction fragment length polymorphism analysis is a rapid and easy method for genotyping of Borrelia species.

Animals↗
PubMed2000

Detection of spirochaetes of Borrelia burgdorferi complexe in the skin of cervids by PCR and culture.

To determine whether deer may play a role in the cycle of the Lyme disease spirochete Borrelia burgdorferi, we sought evidence for the presence of the pathogen in skin of deer and roe deer. Biopsies of 2 mm3 were taken at four different levels from nail to tarsus. A total of 50 animals (200 biopsies) were shot in the Lyme disease foci of Rambouillet during the hunting season 1995-1996 and 1996-1997, from the beginning of November to the end of February. Borrelia burgdorferi s.l. DNA was detected by PCR in 18 biopsies from 14 animals (28%). Borrelia burgdorferi s.str. was predominant (50%), followed by B. garinii (30%) and B. afzelii (10%). Multiple infections were detected in four animals: same species at different levels or two different species from the same biopsy or from different biopsies from the same foot. A total of 125 biopsies were cultivated on BSKH medium. Cultures at 160 days revealed immobile spiralled forms in 10 cultures. One, from a deer killed at the end of December, was confirmed by PCR as B. burgdorferi s.str. These results, frequency of detection of spirochetes by PCR in the skin, multiple infections and alive spirochetes in biopsies taken out side the season of activity of ticks strongly suggest an affinity of Lyme disease spirochetes for skin of cervids.

Animals↗
PubMed1997

[Collecting with the flagging method and fixing on man of Ixodes (Trichotoixodes) frontalis (Panzer, 1795)].

As he was beginning to sort a batch of Ixodid ticks, collected with the flagging technique, the operator noticed that a female tick identified as Ixodes frontalis had fixed itself rapidly on the top of one of his finger. That species is usually considered as "strict-specific to birds". The low frequency of such a fixing on human beings, as for as we know, is of limited value from an epidemiological point of view.

Animals↗
PubMed1996

Prevalence of Borrelia burgdorferi (sensu lato) in Ixodes ricinus (L.) populations in France, according to a phytoecological zoning of the territory.

Ixodes ricinus is considered as the main vector of Lyme Borreliosis in France. The aim of our investigations was to obtain a comprehensive view of the spatial risk linked to the distribution of the species in our country. Previous studies [1] have provided strong evidence that the species populations are widely distributed, so the objective of the present work was to ascertain the bacteriological infection of the tick by the agent of the zoonosis (Borrelia burgdorferi, sensu lato), over the French territory, whatever the ecological conditions may be. For this purpose, we kept the same framework as that used in our acarological investigation, a phytoecological zoning of the territory into 54 geographically separate and ecologically distinct units distributed into three climatic zones. Batches of ticks, picked up in these different phytoecological units (only two thirds of which were sampled), were submitted for bacteriological investigation. A total of 4,673 ticks were examined, individually, for the presence of Borrelia burgdorferi, by immunofluorescence. Percentages of infection according to the various stages of Ixodes ricinus free stages, collected by flagging, were as follows: 4.95% in 3,247 nymphs, 11.2% in 699 males, 12.5% in 727 females. Larvae were ignored. Practically all the tested units harboured the bacterium. The percentage of tick samples (25 ticks or more) absolutely free of Borrelia, wherever they came from, is very low (not exceeding 10 percent of the sampled forests). Our study confirms the assessment of a widespread distribution of the zoonosis in France which was, until now, exclusively based on an approximate distribution of limited human cases observed in the country.

Animals↗
PubMed1994

[The colonization of forested areas by Ixodes ricinus (Linné, 1758) in France: use of the roe deer, Capreolus capreolus (L. 1758) as a biological marker].

The roe-deer is a wild animal for which Ixodes ricinus has a particular fondness. Its territory is similar to that of the ticks and it is a species which is found throughout France yet which rarely leaves its territory. Given these conditions, a systematic parasitological examination of the ungulate can provide pertinent information concerning the forests inhabited by the tick. Since it is difficult to conduct a thorough examination of a large number of roe-deer over a limited space of time and on a large territory, the best solution is to examine the hind feet (hooves and tarsus) of the animal which are widely covered by the preimaginal stages of the tick. This biological material is easily available to the extent that the measurements of the animals are often used for game management. A preliminary study was conducted in Dordogne (southwestern France). Out of the 137 pairs of feet examined more than 50% carried the tick species (larvae or nymphs). The critical analysis of the results obtained throughout the investigation enables us to be more specific about the conditions of application of the advocated method.

Animals↗
PubMed1994

[Ecoepidemiology of Lyme borreliosis in the Rhône-Alps region. Distribution, ecological context, relationship to the distribution of Ixodes ricinus (Linnaeus, 1758)].

The aim of the study was to precise the geographical repartition of Lyme borreliosis in the Rhône-Alpes district, to describe the ecological characteristics of the areas propitious to the disease, and to verify the vectorial competence of I. ricinus. The cases of Lyme disease were located by means of a questionnaire sent to 1156 physicians. The vector role of I. ricinus was studied by two ways: firstly by searching a correlation between the geographical repartition of the tick and that of cases, secondly by proving the Borrelia infection of the tick. Lyme disease is widely spread in the study area, mainly at the foothill level, its repartition is largely coinciding with that of I. ricinus which was found infected by B. burgdorferi (s.l.). However a few cases, located near the Mediterranean area, set an unanswered problem.

Animals↗
PubMed1993

Mediterranean spotted fever in Marseille, France: correlation between prevalence of hospitalized patients, seroepidemiology, and prevalence of infected ticks in three different areas.

We report the results of a comparison of several epidemiologic and ecologic parameters affecting the incidence and seroprevalence of Mediterranean spotted fever (MSF) in northern, central, and southeastern Marseille, an area endemic for this disease. In northern Marseille, the incidence of hospitalized patients with MSF was 24.2/100,000 persons compared with 9.8/100,000 and 8.8/100,000 for the central and southeastern regions, respectively. The seroprevalence in sera from blood donors, determined by microimmunofluorescence and confirmed by Western blot assays, was higher in the northern region than in the other two areas (6.7% versus 3.6% and 2.4%, respectively). This higher prevalence of MSF in the northern part of the city may be related to a greater tick exposure due to a higher number of dogs (32.6/100 inhabitants versus 28.4/100 and 27.2/100 in the central and southeastern regions, respectively) and a higher rate of infection of dogs in the northern region (51.4% versus 43.5% and 39.9%, respectively). The ratio of spotted fever group rickettsia-infected ticks was similar in both the northern and southeastern areas (14.8% and 13.4% respectively), but lower in the central area of the city (8.9%), leading to a higher risk of having MSF after a tick bite in the northern and southeastern parts of Marseille.

Adult↗
PubMed1992

Comparison of serologic typing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein analysis, and genetic restriction fragment length polymorphism analysis for identification of rickettsiae: characterization of two new rickettsial strains.

In 1990, 17 adult Rhipicephalus turanicus ticks were collected in the south of France. Two spotted fever group rickettsiae, Mtu1 and Mtu5, were isolated from the hemolymphs of two of these ticks by the centrifugation shell-vial technique by using HEL cells. These isolates were compared with reference spotted fever group rickettsial serotypes by using three identification methods: microimmunofluorescence serologic typing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and polymerase chain reaction followed by restriction endonuclease fragment length polymorphism analysis. The results obtained by all these techniques showed that Mtu1 and Mtu5 are each previously undescribed rickettsial serotypes. A comparison of the three methods used to identify the isolates led us to the conclusion that, in large-scale epidemiological studies, the simplest way to identify isolates in ticks is to first use the polymerase chain reaction-restriction fragment length polymorphism analysis directly on triturated ticks as a screening method to detect interesting rickettsiae, and then attempt to isolate rickettsiae from ticks for identification by microimmunofluorescence and SDS-PAGE, both of which are time-consuming and expensive to carry out.

Animals↗
PubMed1991

Epidemiology of canine babesiosis in relation to the activity of Dermacentor reticulatus in southern Jura (France).

Dates of onset of canine babesiosis within a hyperendemic focus in France (Rhone Valley, south of Jura and north of the Alps) were compared to the seasonal population level of the adult stage of Dermacentor reticulatus over a 12-month period (December 1982-November 1983). Cases of babesiosis occurred in spring and fall when adult D. reticulatus were active. The fluctuations of the vector tick population and the onsets of canine babesiosis were also correlated with climatic changes: no tick activity or clinical cases of disease were detected in winter (low temperature) or in summer. The slight disparities observed between both distributions might be explained by various factors such as the development of immunity against the parasites, the intervals between tick bites and appearance of symptoms of the disease, or the asynchrony between different biotopes.

Animals↗
PubMed1990

Relationships between the Rhipicephalus sanguineus complex ecology and Mediterranean spotted fever epidemiology in France.

The authors examine the epidemiologic features of Mediterranean spotted fever in France in light of the bioecological peculiarities of each of the three known member of the Rhipicephalus sanguineus tick group (R. sanguineus, R. turanicus, R. pusillus). The results show that R. sanguineus is the main vector. Certain aspects of this tick species are of interest: affinity for man, close contact with humans for a long periods, peak of tick population (preimaginal stages) at the same time as the peak of the disease. The largest populations of R. sanguineus are noted in the endemic zone of human rickettsiosis. The fact that immature stages are more prevalent during the hot season and these forms' ability to bite humans is important and may suggest a role for them in the epidemiology of the disease. The sporadic isolation of this species outside the endemic zone may explain the occurrence of isolated cases of the disease in these areas. We cannot currently exclude vector roles for the two other species, which can parasitize humans, though none of our data supports this hypothesis.

Animals↗
PubMed1990

Isolation by a sensitive centrifugation cell culture system of 52 strains of spotted fever group rickettsiae from ticks collected in France.

Boutonneuse fever caused by Rickettsia conorii is transmitted mainly by the brown dog tick, Rhipicephalus sanguineus. We collected 540 ticks in Marseille, France, and tried to isolate as many strains of rickettsia as possible. Ticks were evaluated for the presence of rickettsia by the hemolymph test and by a new culture system, the centrifugation-shell vial technique. We avoided contamination in the culture system. Prior to ticks being submitted to the hemolymph test, they were disinfected. Only 5.6% (27 of 478) of the cultures were contaminated. A drop of hemolymph from each of 478 R. sanguineus ticks was cultured in two shell vials, and another drop was stained by the Gimenez method or indirect immunofluorescence. Since Gimenez staining in our hands was not satisfactory, comparison of the hemolymph test and culture is based on the results of indirect immunofluorescence. Thus, 50 of 369 (13.5%) examined ticks were hemolymph test positive, and 44 (11.9%) cultures were positive. After disinfection, another pool of 62 ticks were examined by the hemolymph test. The ticks were kept individually in a sterile environment. A few days later, the hemolymph of these ticks was collected again and cultured. The contamination rate was not significantly higher (6.4%) than in the above-described conditions. It allowed us to isolate eight more strains. Thus, we recommend screening ticks with the hemolymph test and culturing only the hemolymph test-positive ticks.

Animals↗
PubMed1988

[The experimental pathogenic effect of Spiroplasma isolated from mosquitoes on the hatching of Aedes aegypti ova and the growth of larva hatched from these eggs].

The authors did study the experimental effects on Aedes aegypti ova of different Spiroplasma strains, isolated from mosquitoes in French Savoy and in Taiwan. The SP7 strain, from Armigeres subalbatus (Taiwan), demonstrates a true pathogenic effect on the larval evolution, without sex ratio modifications, nor bacterial transmission to the adult mosquitoes. The authors present their results and emphasize the difficult use of Spiroplasmas sp.

Aedes↗
PubMed1988

[Natural infestation of domestic cats (Felis catus L.) by Echinococcus multilocularis Leuckart, 1863 (Cestoda): first case in France detected in peri-urban area].

A minute specimen of a tapeworm from the small intestine of a domestic cat is related to Echinococcus multilocularis. The natural infestation of the cat by this species of cestode is demonstrated in France for the first time. The cat was captured in the field around buildings of the neighbourhood of Annemasse (Haute-Savoie). This case illustrates the possibility of an urban life cycle extension of alveolar echinococcosis in the permanent endemic areas of the zoonosis in France and also the eventual risks of contamination for urban dwellers by parasite eggs laying on the ground or on the carnivorous domestic animal furs.

Animals↗
PubMed1987

Mosquito spiroplasmas from France and their ecology.

Spiroplasmas have been isolated previously from a number of blood-sucking arthropods, including ticks, horseflies, and deerflies. More recently, spiroplasmas were isolated from mosquitoes from the USA, France, and Taiwan. Spiroplasmas isolated from mosquitoes from France belong to at least three serogroups and are serologically different from one of the Taiwan isolates, Sp2. Our Ar 1343 strain is the prototype of a new serogroup (XIII). During 3 consecutive years (1983-85), the ecology of these spiroplasmas was studied in different biotopes near, and in, the Isère River Valley in Savoia, France. A total of 23 strains was isolated from four species or groups of mosquitoes (Aedes sticticus/vexans, Ae. cantans/annulipes, Ae. cinereus/geminus and Coquillettidia richiardii). Spiroplasmas were isolated only from female mosquitoes and only during June and July. An as yet unidentified virus was also isolated from three mosquito pools, one of which yielded spiroplasmas. Spiroplasma viruses were not detected. Antibody to our Ar 1357 isolate was found in 4 of 20 sera from cows living in the areas studied, but not in sera from wild rodents or in sera from rabbit or pigeon sentinels. Finally, preliminary results are presented on the effects of experimental infection of Ae. aegypti with the Ar 1357 isolated (serogroup XXII).

Animals↗
PubMed1985

[Spiroplasmas and hematophagous arthropods; prospects in tropical pathology].

Spiroplasmas are original wall-free prokaryotes which exhibit motility and a helical shape although lacking any cell wall or motile apparatus. They are known by phytopathologists because some of them are responsible for severe arthropod-borne plant diseases, such as Spiroplasma citri, the etiologic agent of "citrus stubborn disease". Other spiroplasmas are pathogenic for a number of insects: drosophila, bees and beetles. More recently spiroplasmas were also isolated from ticks, mosquitoes, horse-flies and deer-flies opening a new chapter in medical pathology. These agents are of possible great significance in Tropical Medicine.

Animals↗
PubMed1984

[Detection of the larva of Taenia multilocularis in 2 voles (Microtus arvalis and Clethrionomys glareolus) in a focus of alveolar echinococcosis in the Massif Central (France)].

Small wild rodents were collected and examined during 1983-1984 to investigate parasite-host relationships of Echinococcus multilocularis in one habitat suitable for red foxes of Auvergne (France). The natural infestation of the liver of two different voles, Microtus arvalis and Clethrionomys glareolus, by the larval stage of the cestode is recorded for the first time. In the both cases, the larvae were fully developed and numerous protoscolices were present with some calcareous corpuscules; the expansion of the larvae involved several hepatic lobes in Microtus and was restricted to a single lobe in Clethrionomys. Epidemiological consequences of the receptivity of the two hosts are not yet investigated in the field. However several species of voles inhabiting the same endemic area and which are receptive to the larval stage of alveolar echinococcosis should be a favourable factor of durability for the cestodiasis of the foxes; so the parasite is able of surviving the cyclic and considerable but not simultaneous fluctuations of the three populations of voles which are locally implicated in the zoonosis: M. arvalis, C. glareolus and Arvicola terrestris, by changing from one species to the others.

Animals↗