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PubMed1998

Immunoserologic evidence of Human Granulocytic Ehrlichiosis in Danish patients with Lyme neuroborreliosis.

Human Granulocytic Ehrlichiosis (HGE) is a recently described human illness in the US which manifests as fever, myalgia and headache combined with pancytopenia and elevated concentrations of hepatic transaminases. Genetic analyses indicate that the agent of HGE appears to be an Ehrlichia species that is closely related to E. equi and E. phagocytophila. Ixodes dammini and I. scapularis were identified as potential vectors of HGE. Ixodes ticks are also the vector of Borrelia burgdorferi, the agent of Lyme borreliosis. The presence of antibodies against Ehrlichia in 132 sera from Danish patients with definite Lyme neuroborreliosis were examined in order to provide immunoserologic evidence of this infection in Denmark. Patients with Lyme neuroborreliosis were chosen as a test cohort, as these patients had been infested by a tick sufficient for transmission of B. burgdorferi. All had cerebrospinal fluid lymphocytic pleocytosis. As controls, serum samples from 50 healthy Danish blood donors were included. Of the 132 patients with Lyme neuroborreliosis, 5 (3.8%) reacted with the E. equi antigen substrate at titres 1:128. None of the blood donors were found seropositive for E. equi. At least 2 of the patients found seropositive for HGE constituted probable cases of HGE with E. equi antibody titres of at least 80 combined with fever, headache and myalgias. However, in no cases were we able to detect the presence of the HGE agent in the serum by PCR. We conclude that human exposure to granulocytic Ehrlichiae species may also occur in Europe, although further studies will be necessary to document active infection with these potential pathogens.

Adult↗
PubMed2005

Prevalence and incidence of Lyme borreliosis among Slovene forestry workers during the period of tick activity.

OBJECTIVES: To establish the prevalence and incidence of symptomatic and asymptomatic infection with Borrelia burgdorferi sensu lato during the period of tick activity, to compare the risk of infection with B. burgdorferi s.l. for forestry workers and indoor workers in Slovenia, and to compare the outcome of an in-house immunofluorescent assay (IFA) and a commercially available enzyme-linked immunosorbent assay (ELISA). METHODS: The study included 122 forestry workers; the control group consisted of 93 indoor workers. All participants were examined twice in 2002: before the beginning of tick activity (March) and at the end of tick activity (November). At each examination, principal demographic and epidemiological data were collected and a blood sample taken for serological analysis. Specific IgM and IgG antibodies against B. burgdorferi s.l. in the paired sera were determined with an in-house IFA and a commercially available ELISA flagellin test (DAKO). RESULTS: 9.8% of the forestry workers and 4.3% of the indoor workers tested positive for IgG with the IFA (p = 0.26); 23.8% of the forestry workers and 9.7% of the indoor workers tested positive for IgG with the ELISA (p = 0.02). During the study period the incidence of symptomatic Lyme borreliosis was 2.3% and the rate of IgG and/or IgM seroconversion of 10.2% was the same with both tests. CONCLUSIONS: The seroprevalence of antibodies against B. burgdorferi s.l. among the Slovene forestry workers was greater than among the indoor workers, but the difference between the two groups was not significant when the IFA was used. The incidence of Lyme borreliosis during the period of tick activity was lower than we expected, with a large proportion of seroconversions being asymptomatic.

Adult↗
PubMed2006

Developmental profiles in tick water balance with a focus on the new Rocky Mountain spotted fever vector, Rhipicephalus sanguineus.

Recent reports indicate that the common brown dog tick, or kennel tick, Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) is a competent vector of Rocky Mountain spotted fever in the U.S.A. This tick is of concern to public health because of its high frequency of contact, as it has a unique ability to thrive within human homes. To assess the moisture requirements necessary for survival, water balance characteristics were determined for each developmental stage, from egg to adult. This is the first time that water relations in ticks have been assessed throughout the complete lifecycle. Notably, R. sanguineus is differentially adapted for life in a dry environment, as characterized by a suppressed water loss rate distinctive for each stage that distinguishes it from other ticks. Analysis of its dehydration tolerance limit and percentage body water content provides no evidence to suggest that the various stages of this tick can function more effectively containing less water, indicating that this species is modified for water conservation, not desiccation hardiness. All stages, eggs excepted, absorb water vapour from the air and can drink free water to replenish water stores. Developmentally, a shift in water balance strategies occurs in the transition from the larva, where the emphasis is on water gain (water vapour absorption from drier air), to the adult, where the emphasis is on water retention (low water loss rate). These results on the xerophilic-nature of R. sanguineus identify overhydration as the primary water stress, indicating that this tick is less dependent upon a moisture-rich habitat for survival, which matches its preference for a dry environment. We suggest that the controlled, host-confined conditions of homes and kennels have played a key role in promoting the ubiquitous distribution of R. sanguineus by creating isolated arid environments that enable this tick to establish within regions that are unfavourable for maintaining water balance.

Animals↗
PubMedDate not supplied

[The reaction of taiga ticks to an attractant. 1. The experimental contact of nymphs with attractant-acaricidal granules].

Four experimental variants used the following: 1) granules only from a filler (control); 2) those from a filler and an attractant; 3) and 4) those from a filler, an attractant, and a toxicant (permethrin or lambda cigalothrin, respectively). Each experiment used 20 nymphs of the first laboratory generation. 90 and 25% were in contact with attractive and control granules, respectively. Out of the nymphs in experiments 3 and 4 granules, 94 and 100% died. The contacts of 4 sec or more duration led to death. The experimental findings suggest that the designing and application of attractive acaricidal granules in the foci of tick-borne encephalitis and Lyme's disease are promising.

Animals↗
PubMed2005

Multiplex detection of Ehrlichia and Anaplasma species pathogens in peripheral blood by real-time reverse transcriptase-polymerase chain reaction.

Tick-borne infections are responsible for many emerging diseases in humans and several vertebrates. These include human infections with Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Ehrlichia ewingii. Because single or co-infections can result from tick bites, the availability of a rapid, multiplex molecular test will be valuable for timely diagnosis and treatment. Here, we describe a multiplex molecular test that can detect single or co-infections with up to five Ehrlichia and Anaplasma species. The test protocol includes the magnetic capture-based purification of 16S ribosomal RNA, its enrichment, and specific-pathogen(s) detection by real-time reverse transcriptase-polymerase chain reaction. We also report a unique cloning strategy to develop positive controls in the absence of a pathogen's genomic DNA. The test was assessed by examining blood samples from dogs suspected to be positive for ehrlichiosis. The dog was chosen as the model system because it is susceptible to acquire infections with up to five pathogens of the genera Ehrlichia and Anaplasma. The test identified single infections in the canine host with E. chaffeensis, E. canis, E. ewingii, A. phagocytophilum, and A. platys and co-infection with E. canis and A. platys. The multipathogen detection and novel positive control development procedures described here will be valuable in monitoring infections in people, other vertebrates, and ticks.

Anaplasma↗
PubMed1993

[Health economics of early summer meningoencephalitis in Austria. Effects of a vaccination campaign 1981 to 1990].

Tick-borne encephalitis (TBE) was until the early 1980s among the most frequent causes of viral induced central-nervous infectious diseases in Austria. Since 1981 the vaccination was forced by intensive media campaigns. Aim of this study was to investigate the effects of the media campaigns and to evaluate them under health economic criteria. The number of hospitalized TBE-cases declines from 1981 to 1990, the linear trend shows a reduction from 427 to 109. If the linear trend from 1971 to 1980 would have continued the respective number in 1990 would have been 585 cases. Thus the model shows that from 1981 to 1990 more than 50% or 2,690 out of 5,368 possible cases are prohibited, from 1991 to 2000 based on the 1990 vaccination rate approximately 85% or 500 cases annually. In the age group 7 to 14 years the proportion of protected exposed is almost 97%. The loss of quality of life is higher than represented by the inpatient statistics. Many of the TBE victims have chronic impairments, mainly due to paresis and depression. Based on the 1990 cost data economic benefits for the social insurance companies in the decade 1981 to 1990 are AS 147 millions for inpatient care, respectively AS 108 millions for loss of productivity and AS 77 millions for early retirement, resulting in total benefits of AS 331 millions. The estimated benefits for 1991 to 2000 based on 1990 cost data are AS 270 millions for inpatient care, AS 200 millions for loss of productivity, and AS 368 for early retirement (total AS 828 millions).

Austria↗
PubMed1985

[Use of an immunofluorescence micromethod for determining the antigens of the influenza and tick-borne encephalitis viruses].

The diagnostic possibilities of several variants of the solid-phase immunofluorescent micromethod (requiring 100-200 microliter of the reaction mixture), intended for the determination of influenza virus and tick-borne encephalitis virus antigens in material obtained from patients and ticks, have been studied. A high degree of correlation between the results obtained by the methods under investigation and the control methods has been established.

Animals↗
PubMed2001

Evolution and function of tandem repeats in the major surface protein 1a of the ehrlichial pathogen Anaplasma marginale.

The major surface protein (MSP) 1a of the ehrlichial cattle pathogen Anaplasma marginale, encoded by the single-copy gene msp1alpha, has been shown to have a neutralization-sensitive epitope and to be an adhesin for bovine erythrocytes and tick cells. msp1alpha has been found to be a stable genetic marker for the identification of geographic isolates of A. marginale throughout development in acutely and persistently infected cattle and in ticks. The molecular weight of MSP1a varies among geographic isolates of A. marginale because of a varying number of tandemly repeated peptides of 28-29 amino acids. Variation in the sequence of the tandem repeats occurs within and among isolates, and may have resulted from evolutionary pressures exerted by ligand-receptor and host-parasite interactions. These repeated sequences include markers for tick transmissibility that may be important in the identification of ehrlichial pathogens because they may influence control strategies and the design of subunit vaccines.

Amino Acid Sequence↗
PubMed2000

Humoral immune response of dogs immunized with salivary gland, midgut, or repeated infestations with Rhipicephalus sanguineus.

The antibody (Ab) responses of dogs immunized with adult tick salivary gland (TSG), midgut (TMG), or repeated infestations of Rhipicephalus sanguineus were monitored to determine if there is an association between Ab production and R. sanguineus performance. Tick-naïve dogs were immunized with TSG or TMG and subjected to two challenge infestations. The control group was infested five times at 21-day intervals. The ELISA technique was used to measure Ab levels in sera from these dogs, which expressed different forms of resistance against R. sanguineus. In dogs immunized with TSG or TMG, similar Ab levels were detected against TMG, TSG, muscle, synganglion, and reproductive organs. However, these sera had different Ab levels against egg mass, unfed larvae, fed larvae, and nymph antigens. Ab levels to muscle, nerve, and reproductive antigens were lower than those observed when TMG or TSG antigens were used. Sera from dogs immunized with TMG or TSG responded to most tick stages or tissue antigens, whereas repeated infestation sera showed the lowest response among the three groups.

Animals↗
PubMed1985

New methods of applying drugs for the control of ectoparasites.

A brief history of the development of methods used to apply drugs (commonly called insecticides or acaricides) to domesticated animals for the control of ectoparasites is presented. The focus is on methods used in the United States for treating cattle, sheep and goats, and swine. Details of the evolution of treatment methods are presented for lice, flies, cattle grubs, keds, ticks, and other arthropods. In general, treatment methods have undergone some change over the years; while, in contrast, treatment materials have changed considerably. Three trends in treatment methods become obvious - (1) Gradual reduction in the amount of treatment material applied dermally from spray or dip to pouron, to spoton, and to insecticide-impregnated ear tags, (2) Increasingly wider use of animal systemic insecticides administered orally or percutaneously to control a variety of ectoparasites, and (3) The development of new methods (sustained release devices) to lengthen the residual effectiveness of treatments. Unfortunately, lengthened residual effectiveness may lead to resistance of important ectoparasites to the treatment materials.

Animals↗
PubMed2006

Anaplasma marginale field challenge: protection by an inactivated immunogen that shares partial sequence of msp1alpha variable region with the challenge strain.

Twenty four Hereford heifers free of anaplasmosis were allotted into three groups of eight animals each and inoculated three times with adjuvant in Puck saline as control or 50 microg and 100 microg of total protein of Anaplasma marginale initial bodies from three Mexican strains which share the same variable region of msp1alpha and msp4. Inoculation with the adjuvant or the immunogen at either of the two protein doses did not induce any undesirable changes attributable to inoculation in vaccinates or controls. On day 78 post vaccination animals were released in a ranch where bovine Anaplasmosis is endemic. The A. marginale strain prevalent in this ranch shares some of the msp1alpha tandem repeats with and the strains used in the vaccine. After release, all animals became infested with Boophilus microplus ticks and flies. During the challenge period, between days 279 and 300, loss of PCV due to clinical anaplasmosis in control animals was statistically higher from vaccinated animals. Likewise, controls mean peak rickettsemia was also significantly higher (p< or =0.01) than vaccinates' rickettsemias. The antibody responses of all vaccinates after the third vaccination reached OD values above 2.0 on day 49 and were different from controls (p<0.01). IgG(2) responses from both groups of vaccinates were different from controls (p<0.01). Vaccinates which required treatment, also showed the lowest IgG(2) and substantial IgG(1) responses. After contact with the rickettsia, controls developed clinical disease and 7 out of 8 required treatment, while vaccinates in general showed no substantial changes in hematocrit or rickettsemia and only one animal in each group required treatment. Our present results show that vaccination with either 50 microg or 100 microg of protein from purified IB derived from three strains induced protection to resist the challenge with the a field strain that shares some of the tandem repeats of MSP1a.

Anaplasma marginale↗
PubMed2002

The dog factor in brown dog tick Rhipicephalus sanguineus (Acari: Ixodidae) infestations in and near human dwellings.

Three cases of the tick Rhipicephalus sanguineus infiltration in or near human dwellings caused by dogs, and their influence on epidemiological features of human habitats have been investigated. (a) The observation of dogs kept indoors proved that single tick females could engorge and oviposit inside apartments followed by the development of subadults. (b) Abundant micropopulations of ticks were formed in small yards or gardens near the dwellings where dogs lived in kennels. (c) A huge field population of R. sanguineus was observed on a farm where watchdogs constantly patrolled along the farm perimeter. Tick abundance near the kennels and in the permanent resting sites of the dogs reached more than 30 adults per 10 min of collecting, while the number of adults on a dog reached 100. Unfed adult females under conditions of constant dog availability had a larger scutal index than females collected in the control field site. On the basis of circumstantial evidence it is possible to conclude that under the above conditions tick development may change from the normal 3-host cycle to a 2-host cycle. Ticks in the field had one complete generation per year. Ticks on the farm, as well as ticks in kennels, developed faster and a significant part of their population had two complete generations per year. R. sanguineus is the main vector and reservoir of a pathogen from the Rickettsia conorii complex, the causative agent of Israeli tick typhus. The described conglomerations of R. sanguineus create a great risk to humans who can be attacked by infected ticks in and around their homes, even in large towns. Such a feature of the tick life history most likely exists not only in Israel but in other countries as well.

Animals↗
PubMed1992

Resistance to tick-borne fever in young lambs.

Lambs were inoculated with Ehrlichia phagocytophila infected blood at the age of either two or six weeks. The temperature response and degree of parasitaemia were both most pronounced in the lambs inoculated at six weeks old. The half-life of antibodies to E phagocytophila was estimated to be 17.5 days. Lambs inoculated with tick-borne fever (TBF) had lower liveweights in the autumn than TBF-free controls.

Animals↗
PubMed1994

Tick infestations on cattle vaccinated with extracts from the eggs and the gut of Boophilus microplus.

Extracts prepared from the membranes of eggs (EM) and guts (GM) of Boophilus microplus were used to immunise cattle which were then infested twice with 20,000 larval ticks 1 week apart. EM antigens did not protect cattle against challenge with ticks, despite high levels of anti-egg antibodies in the sera of the vaccinated cattle, detected by an indirect enzyme-linked immunosorbent assay (ELISA). Cattle vaccinated with GM, however, had high levels of antibodies against GM and were protected significantly against challenge with B. microplus. Anti-EM and anti-GM antibodies in the sera of cattle cross-reacted significantly with GM and EM respectively on ELISA and recognised both specific and common antigens in extracts of the eggs and guts of B. microplus on Western blots. Exposure of cattle to field infestation with ticks during vaccination with gut antigens did not adversely affect the levels of antibodies generated.

Animals↗
PubMed1995

Environmental risk and prevention of Lyme disease.

An understanding of the environmental determinants of Lyme disease risk is essential to evaluate human disease potential and to recommend strategies for disease prevention. Tick vectors of Lyme disease require a vertebrate blood meal during each of three motile developmental stages (larva, nymph, and adult). Although the immature stages (larvae and nymphs) exhibit broad and overlapping host ranges, adult ticks are primarily dependent on deer for feeding and reproduction. Consequently, the distribution and abundance of these ticks often reflect those of deer. Several species of smaller mammals and some birds that host immature ticks are also competent reservoirs for Borrelia burgdorferi, which becomes established within the tick population during feeding. The relative abundance of these host species and their ability to infect ticks are key factors in determining the distribution of Lyme disease risk in the local environment. Available methods for reducing the risk of Lyme disease in the environment include the application of insecticides and use of deer fencing, which have been shown to be 83-97% effective in reducing risk. However, the adverse environmental impact of insecticides and high cost of deer fencing limit these methods to high-risk areas where human exposure is constant and unavoidable (i.e., residential or occupational). Personal protection in high-risk areas can lessen the likelihood of contact with ticks. Future prevention methods may include host-targeted insecticides, environmental alteration, and biologic control. Moreover, research is currently directed to identifying antigens for use in recombinant human vaccines.

Animals↗
PubMed1996

Efficacy of local inhibition of procoagulant activity associated with small-diameter prosthetic vascular grafts.

PURPOSE: Graft procoagulant activity is determined by thrombin (IIa) and activated factor X (Xa) that binds to thrombus. Thrombus-associated factor Xa and thrombin are resistant to antithrombin III-dependent therapy (heparin). To avoid complications and costs associated with systemic administration, we evaluated whether locally applied antithrombotic agents inhibit prosthetic graft procoagulant activity under no-flow and low-flow conditions. METHODS: Four-millimeter-diameter collagen-coated grafts were preclotted in recalcified human plasma, washed, immersed in antithrombotic agents (either 100 nm hirudin, 20 microns D-Phe-L-Pro-L-Arg chloromethylketone, 5 microns tick anticoagulant peptide or 5 or 10 micrograms/ml tissue factor pathway inhibitor) or saline solution, and extensively rewashed. Grafts were exposed to recalcified plasma either in multiwell plates or underwent perfusion at 1 ml/min flow rate. Fibrinopeptide A, which reflects fibrin elaboration, was measured as a marker of thrombin activity. RESULTS: Inhibitors reduced fibrinopeptide generation at 8 minutes by 55% (tissue factor pathway inhibitor), 57% (hirudin), or 63% (tick anticoagulant peptide and D-Phe-L-Pro-L-Argchloromethylketone) compared with the control agents (p < 0.05). Under low-flow conditions tissue factor pathway inhibitor and hirudin reduced fibrinopeptide generation at 13 minutes by 61% and 49%, respectively, when compared with control agents (p < 0.05). CONCLUSIONS: Graft-associated inhibitors targeted at factors IIa, Xa, or tissue factor/VIIa/Xa complex effectively reduce procoagulant activity on prosthetic grafts. The success of local application of antithrombotic agents in attenuating early fibrin formation suggests that this strategy could favorably influence acute graft patency, and we speculate these agents may improve long-term graft patency as well.

Amino Acid Chloromethyl Ketones↗

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