Showing papers on "Ixodes ricinus published in 1987"

Infectiousness for humans of Ixodes ricinus containing Borrelia burgdorferi

Abstract: Summary We studied the rate of transmission of Borrelia burgdorferi from ticks (Ixodes ricinus) to man under field conditions in a case control study. At a holiday camp in southern Germany 384 ticks were removed from 272 persons. Information on symptoms possibly related to Borrelia infection were obtained by a questionnaire to be sent back six weeks after the tick bite. Ticks were examined by immunofluorescence microscopy (IFT) for Borrelia and 49 (12.8%) were found positive. Blood was obtained from 41 persons bitten by Borrelia positive and 41 age and sex matched persons bitten by Borrelia negative ticks. Sera from age and sex matched patients of local hospitals and clinics served as additional controls. Antibody titers were obtained by indirect IFT about 13 weeks after tick bite. Titers 1 : > 32 suggested recent infection and 1 : 32 immunity. In the exposed group there were about half as many persons with titers 1 : 32, but 5/6 of these persons in the control group recalled additional tick bites in 1984. Only one child (in the exposed group) developed an Erythema chronicum migrans, and no other Borrelia related manifestations were reported. The manifestation rate of the Borrelia-related disease was 4%.

A disease resembling louping-ill in sheep in the Basque region of Spain.

Abstract: A clinical syndrome resembling louping-ill which primarily affects lambs and yearlings in the Basque region of Spain is described. The disease has been observed for several years during May and June after the sheep flocks have been taken to the mountain grazings where the sheep tick (Ixodes ricinus) is known to occur. Examination of the brain from one of the affected animals revealed histological changes indistinguishable from those caused by louping-ill virus. In addition antibody that reacted with louping-ill virus antigen was detected in the serum of 57 per cent of the sheep tested from the affected flocks but in only 0.8 per cent of sera from flocks free of the disease. These preliminary results suggest that louping-ill or a related tick-borne virus is responsible for ovine encephalomyelitis in Spain.

Investigations of ticks for the presence of Borrelia in Czechoslovakia.

Abstract: Summary More than 570 ticks from different parts of the country were studied microscopically. In 45 cases (8%) Borreliae were found. The infectivity rate of ticks in different foci varied from 3–11%, in some instances nearly 20%. Only Ixodes ricinus, male and female ticks were positive in this study.

Lyme borreliosis in South Germany. Epidemiologic data on the incidence of cases and on the epidemiology of ticks (Ixodes ricinus) carrying Borrelia burgdorferi

Abstract: Among 2403 ticks (Ixodes ricinus) tested in 1985 for Borrelia 328 (13.6%) were carriers (adults about 20%, nymphs about 10%, larvae about 1%). The highest prevalence of infected ticks was among adult ticks in the Isar region north of Munich (33.8%). Among 9383 persons whose serum had been examined by fluorescence serology in 1985 and 1986, 1035 (11%) had raised Borrelia-specific IgG and/or IgM antibodies greater than or equal to 1:64. In 18.7% only IgM antibodies were demonstrated. Among 375 proven cases there were 78 with erythema migrans, 211 with neurological signs, 48 with Lyme arthritis and 36 with acrodermatitis. Seasonal incidence peaks were in June-August for erythema migrans, July-September for neurological signs, with no clear-cut seasonal peaks with Lyme arthritis and acrodermatitis. The incubation time for 80% of cases of each abnormality was 5-29 days for erythema migrans, 20-59 for neurological signs and 2-8 months for Lyme arthritis. Erythema migrans was most frequent among those aged 30-60 years, neurological signs among children and juveniles up to 20 years and those aged 40 to 70 years, Lyme arthritis among those aged 30-60 years, and acrodermatitis among those aged 40-80 years. Significantly more women than men developed acrodermatitis.

Lyme disease (borreliosis) in southern Germany: epidemiological data on the prevalence of cases and on the infection of ticks (Ixodes ricinus) with Borrelia burgdorferi.

Abstract: Among 2403 ticks (Ixodes ricinus) tested in 1985 for Borrelia 328 (13.6%) were carriers (adults about 20%, nymphs about 10%, larvae about 1%). The highest prevalence of infected ticks was among adult ticks in the Isar region north of Munich (33.8%). Among 9383 persons whose serum had been examined by fluorescence serology in 1985 and 1986, 1035 (11%) had raised Borrelia-specific IgG and/or IgM antibodies greater than or equal to 1:64. In 18.7% only IgM antibodies were demonstrated. Among 375 proven cases there were 78 with erythema migrans, 211 with neurological signs, 48 with Lyme arthritis and 36 with acrodermatitis. Seasonal incidence peaks were in June-August for erythema migrans, July-September for neurological signs, with no clear-cut seasonal peaks with Lyme arthritis and acrodermatitis. The incubation time for 80% of cases of each abnormality was 5-29 days for erythema migrans, 20-59 for neurological signs and 2-8 months for Lyme arthritis. Erythema migrans was most frequent among those aged 30-60 years, neurological signs among children and juveniles up to 20 years and those aged 40 to 70 years, Lyme arthritis among those aged 30-60 years, and acrodermatitis among those aged 40-80 years. Significantly more women than men developed acrodermatitis.

Cypermethrin pour-on for the control of ticks (Ixodes ricinus) on sheep.

Abstract: Trials were carried out on 11 farms to assess the effectiveness of 2.5 per cent w/v cypermethrin pour-on for the control of ticks on sheep. Treatment at the rate of 5 ml/10 kg bodyweight gave 92 per cent control of ticks on ewes for up to nine weeks and 88 per cent control on lambs for up to eight weeks.

[Epidemiology of Ixodes-Borreliosis in Southern Germany].

Abstract: Intimate adaptation occurs between European strains of Borrelia burgdorferi and the local hard tick Ixodes ricinus. I. dammini, the important vector in USA, could not be infected experimentally with a strain of the lyme spirochete from Southern Germany. Other species of blood suckers are sometimes able to maintain uptaken spirochetes for a few days, but never to compensate the tick vector. Man seems to be a good host for B. burgdorferi but without epidemiological significance due to his poor vector role for ticks. The Ixodes-borreliosis is an anthropozoonosis. Well-known animal hosts for the three life stages of the tick are possible carrier hosts for B. burgdorferi as well. It has been established here for the first time in Europe that common wild-rodent species may be of some significance as hosts for the spirochete, as it is well-known in North America. Serological evidence shows, that dogs and grasing cattle in Southern Germany seem to play an important role in B. burgdorferi's outdoor circulation. 36 out of 72 dogs (= 50%) and 22 out of 66 cattle (= 33%) reacted significantly positive in the IFAT if local strains of B. burgdorferi were used as antigen. No serological cross reactions have been observed with Leptospira infections in dogs and cattles.

Ein Beitrag zur Ektoparasitenfauna der Zugvögel in Norditalien1

Abstract: Ectoparasites of migrating birds in North Italy (Ixodoidea, Hippoboscidae, Acari) A survey of ectoparasites of migrating birds in the surroundings of the Lago di Como revealed the following species: a. ticks (Ixodidae, Argasidae): Ixodes ricinus, Haemaphysalis punctata, Argas persicus; b. louse flies (Hippoboscidae): Ornithomya avicularia, O. chloropus, O. fringillina; c. skin mites (Epidermoptidae): Microlichus avus; d. feather mites (Proctophyllodidae): Proctophyllodes anthi. All of them except for I. ricinus were species very rarely found in Italy. Zusammenfassung Am Comer See in Norditalien wurden Zugvogel auf Ektoparasiten untersucht. Zecken (Ixodoidea), Lausfliegen (Hippoboscidae) und Milben (Acari) wurden gesammelt und folgende, bis auf I. ricinus selten nachgewiesene Arten gefunden: Areas persicus, Ixodes ricinus, Haemaphysalis punctata, Ornithomya avicularia, O. fringillina, O. chloropus, Microlichus avus, Proctophyllodes anthi.

A record of trypanosomes from Ixodes ricinus in Britain

Abstract: There have been frequent reports of trypanosome infections in both hard and soft ticks throughout the world (see Table 1). The significance of these infections in the life cycle of trypanosomes is unknown but recent studies indicate that, at least in Africa and India, ticks of the genera Rhipicephalus, Hyalomrna and Boophilus harbour Trypanosoma theileri Laveran or T. theileri-like organisms (Burgdorfer et al., 1973; Shastri & Deshpande, 1981; Morzaria et al., 1986), common endoparasites of cattle and other Bovidae (Wells, 1976). Rehacek et al. (1974) and Aeschlimann et al. (1979) reported finding trypanosome infections in Ixodes ricinus L. in Central Europe but neither group indicated the likely source of such infections. Following these records we undertook a study to ascertain if Ixodes ricinus harboured trypano-

Ixodes ricinus, the sheep tick : ecology and disease

Abstract: Relevant literature was reviewed and the ecology of the sheep tick, Ixodes ricinus and associated disease problems studied in south west Scotland. The development and maintenance of a colony of I.ricinus in the laboratory to provide tick-borne fever (T.B.F.) infected and T.B.F. free ticks for electron microscopic and tick pyaemia transmission studies was described. Additionally development times for each instar were measured during routine colony maintenance. The activity and development of I.ricinus was measured over three years at two sites on Ayrshire sheep farms by blanket drags of pasture areas and tick counts on sheep. Engorged stages were placed in nylon mesh tubes under the vegetation mat, in order to monitor development to subsequent stages. In all instances development to the next instar occurred during the late summer or autumn. Activity patterns varied from year to year with a prolonged period of summer activity in 1984, a bimodal distribution in 1985 and a single spring peak in 1986. Meteorological data was recorded in an attempt, only partially successful, to apply the model devised by Gardiner and Gettinby (1983) to data from these studies. A postal questionnaire was circulated to 300 farmers in Ayrshire and Argyll concerned with seasonal and local distribution of ticks, disease problems and control measures. The replies indicated a high tick incidence in Argyll and marked disease problems in certain regions of Ayrshire where ticks were present. Several of the farms were investigated in more detail by farm visits and examination of blood samples. Experimental tick-borne fever (T.B.F.) infections induced in young lambs were monitored by measurement of rectal temperatures, haematology, assessment of parasitaemias and neutrophil function tests. The classical febrile response accompanied by acute parasitaemia, lymphocytopaenia and followed by neutropaenia was recorded. Additionally an impairment of neutrophil function was demonstrated prior to the neutropaenia using an in vitro assay of neutrophil function. A counter immunoelectrophoresis (CIE) test was developed to detect antibodies produced after T.B.F. infection. Sera from experimental infections in lambs and goats were used to determine the interval after primary infection before antibody could be detected, this was shown to be 9-11 days post intravenous inoculation of the organism and the period of persistence 6-10 weeks in lambs. Four hundred and thirteen ovine field sera obtained from sheep of all ages from predominantly tick infested regions of Scotland and the north of England were tested with a positive rate of 18.2%. When CIE serology was coupled with conventional examination of blood smears the detection rate for ovine T.B.F. was doubled. Additionally, antibodies were detected in a number of sera from cattle, goats and deer using CIE. An electron microscopic technique was developed to demonstrate C.phagocytophila in I.ricinus. This technique was subsequently applied to ticks collected from one sheep farm in an attempt to estimate the level of infection. C.phagocytophila infection was absent from larvae, while 44% of nymphae were infected and 32 % of adults. This result supports the previous finding that transovarial transmission does not occur. Recent publications have indicated that an important aspect of T.B.F. infection in lambs is the associated immunosuppression which allows invasion of secondary pathogens, notably Staphylococcus aureus the causal agent of tick pyaemia. Several experiments were therefore conducted in lambs and mice to examine this aspect. In mice B-lymphocytes were depressed using cyclophosphamide (CY) [ to mimic one aspect of T.B.F. infection] and the mice subsequently challenged with Staphylococcus aureus administered by various routes. Death rates , lesion formation and bacteriological isolations were greater in mice pre-treated with CY. The experiment was repeated in young lambs using T.B.F. rather than CY as a potential suppressive agent. Five days after T.B.F. infection, S.aureus contaminated ticks were allowed to attach and engorge upon the lambs. At necropsy, abscesses from which S.aureus was recovered, were present in the lungs and livers of lambs given T.B.F. and exposed to contaminated ticks, but not in controls which were only exposed to contaminated ticks. This is believed to be the first experimental production of tick pyaemia in lambs using the sheep tick I.ricinus as a mechanical vector of S.aureus.Control of I.ricinus is traditionally by whole body immersion in acaricidal preparations; however more recently synthetic pyrethroid pour-on formulations have been available. Field trials to assess the efficacy of two synthetic pyrethroid pour-on products are described. Tick counts were performed on treated and control lambs and hoggs, disease levels assessed and other effects of the treatment monitored. Results indicate a degree of tick control was achieved , but disease problems still occurred.