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PubMed1995

Anti-idiotypic antibodies as surrogate antigens for vaccinating against the cattle tick, Boophilus microplus.

QU13, a monoclonal antibody (mAb) raised against midgut (GM) antigens from Boophilus microplus and shown to recognise antigens which protect cattle from tick challenge was used to immunise cattle and rabbits to produce anti-idiotypic antibodies (AIA). Polyclonal antisera against mAb QU13 were produced in rabbits and cattle. AIA were purified from these antisera by affinity chromatography procedures. These purified AIA were found to block mAb QU13 binding to GM in enzyme-linked immunosorbent assay (ELISA). AIA purified from bovine antiserum elicited an immune response in cattle to antigens extracted by detergent from the midgut of B. microplus (TXGM) after the fourth vaccination (P = 0.06) compared with the bovine immunoglobulin (Ig) control. The mean antibody level in the group of experimental cattle vaccinated with AIA purified from rabbit antisera was significantly higher (P < 0.03) than that of bovine Ig control cattle after the fourth vaccination and an anamnestic response (P < 0.11) occurred in the rabbit AIA vaccinated group of cattle when a single booster dose of 300 micrograms of TXGM was given after the first tick challenge. The positive control group of cattle vaccinated with TXGM were significantly protected (P < 0.05) against tick infestation after the booster dose of 300 micrograms of TXGM. The AIA vaccinated groups of cattle were not protected against challenge with 20,000 larval ticks either before or after the booster injection of 300 micrograms of TXGM.

Animals↗
PubMed1967

The public health importance of tick-borne encephalitis in Europe.

After an historical survey establishing the distinction between Russian spring-summer encephalitis, a serious disease with a high mortality rate caused by a virus spread by the tick Ixodes persulcatus, and the milder Central European encephalitis, which is spread by I. ricinus, the public health aspects of the latter disease are discussed. The factors affecting the incidence of the disease-tick population, role of rodents and insectivores, etc.-are considered. Only a small proportion of those infected develop clinical symptoms. Measures for the control of the disease include (a) vaccination of humans, (b) reduction of the tick population by cultivation of the land, by spreading the enemies of ticks and by dusting with insecticides, and (c) reduction of the infectivity of ticks by vaccination of domestic animals. It is concluded that, under the conditions prevailing in Central Europe, mass vaccination is not to be recommended, although those working regularly within a natural focus of infection should be vaccinated.

Encephalitis, Arbovirus↗
PubMed1993

Occurrence of antibodies to Borrelia burgdorferi in patients with nonspirochetal subacute bacterial endocarditis.

OBJECTIVE: To determine the prevalence and specificity of antibodies to Borrelia burgdorferi in patients with nonspirochetal subacute bacterial endocarditis and assess whether increased levels of antibodies to B. burgdorferi were attributable to rheumatoid factor. DESIGN: Retrospective case-control study. SETTING: Urban referral center in an area devoid of infected ticks as a source of endocarditis sera. PATIENTS: Sera from 30 consecutive patients with culture-proven subacute endocarditis between 1979 and 1981 were compared with 30 control sera collected between 1989 and 1990. In addition, sera from 20 consecutive patients with rheumatoid arthritis who were positive for rheumatoid factor were collected between 1991 and 1992. Sera were compared with a convenience sample from 15 patients who met the criteria for Lyme disease. MEASUREMENTS: Antibodies to B. burgdorferi were assessed by enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis. IgM rheumatoid factor was quantified using solid-phase radioimmunoassay or latex agglutination techniques. RESULTS: Thirteen of 30 patients with endocarditis (43%) compared with 3 of 30 normal controls (10%) had increased levels of antibodies to B. burgdorferi (P < 0.01). Of these 13 patients, only 1 had an immunoblot consistent with previous infection. The others had nonspecific immunoblots: 5 showed isolated 60-kd reactivity; 1 patient had isolated 41-kd reactivity; and 6 had no bands of reactivity. Immunoblots of the 3 controls with increased antibodies showed only isolated 41-kd reactivity. Thus, the specificity of the B. burgdorferi antibody test in patients with endocarditis was only 60% (95% CI, 42% to 78%), compared with 90% (CI, 79% to 100%) in controls. No correlation was noted between IgM rheumatoid factor and antibodies to B. burgdorferi in patients with endocarditis (r = 0.2; P > 0.2). Only 1 of 20 patients with rheumatoid arthritis without known bacterial infections had antibodies to B. burgdorferi. CONCLUSIONS: Although a positive ELISA test for B. burgdorferi may be a "true positive," a positive serologic test alone does not ensure that the clinical problem is due to Lyme borreliosis. Cross-reactive antibodies to shared epitopes between B. burgdorferi and the endocarditis organism may account for the high false-positive results.

Antibodies, Bacterial↗
PubMed1994

[TBE-immunoglobulins--a critical assessment of efficacy].

Since there is no specific treatment for tick-borne encephalitis (TBE), immunoprophylaxis is used in endemic areas for controlling this disease. Active immunization has been shown to be effective and safe, and a restrictive immunization policy is generally accepted in Switzerland. However, the use of TBE-immunoglobulin for passive immunization after tick exposure is controversial. This article demonstrates that the published reports on the protection rate of TBE-immunoglobulin do not stand up to critical analysis. Efficacy has never been proved. Therefore, the use of TBE-immunoglobulin must be based upon practical or theoretical arguments. Routine administration of this preparation in endemic areas cannot be recommended.

Encephalitis Viruses, Tick-Borne↗
PubMed2004

High seroprevalence of granulocytic ehrlichiosis distinguishes sheep that were the source of an alimentary epidemic of tick-borne encephalitis.

A sheep herd from which contaminated cheese was produced, causing 21 cases of alimentary tick-borne encephalitis (TBE) in human beings, was tested serologically for the presence of specific antibodies against both the TBE virus (TBEV) and Anaplasma phagocytophilum, the cause of tick-borne fever (TBF) in ruminants, and compared with three other herds variously exposed to tick bites but without any TBE history. Virus-neutralisation (VN) with the TBEV strain Hypr and CV-1 cells was used in TBE tests, and indirect immunofluorescence assay (IFA) with neutrophils from goats experimentally infected with A. phagocytophilum was used for TBF testing. In 13 sheep from the incriminated herd (N =41), VN titres ranging from 1/4 to 1/128 traced previous TBE infection and all sheep had elevated titres of A. phagocytophilum antibodies ranging from 1/80 to 1/5120 in IFA, whereas two other herds (N = 8 and 9) were seronegative for TBEV and had significantly lower levels of A. phagocytophilum antibodies, corresponding to a lesser challenge from TBF. A control herd (N = 10) that was grazed on tick-free meadows in north Norway was completely seronegative. The respective distributions of positive titres of A. phagocytophilum and TBEV antibodies in the incriminated herd were not mutually random; the animals with higher anti-A. phagocytophilum titres tended to have lower anti-TBEV titres and vice versa (Spearman correlation coeff. =-0.86, p< or =0.01). The authors hypothesize that the immunosuppressive effect of TBF co-infection in sheep could be a contributory cause of TBE-virus contamination of milk, an aspect of TBE epidemiology that has not been considered thus far.

Anaplasma phagocytophilum↗
PubMedDate not supplied

[The impact of electromagnetic radiation at microwave frequency (9.8 HhZ)on the embryonic and postembryonic development of the tick Hyalomma asiaticum (Acarina, Ixodidae)].

Low-power (20 microW/cm2) microwave-modulated radiation at a carrier frequency of 9.8 Hhz is shown to affect the course and specific features of ontogenesis of the ick H. asiaticum. The actin of microwave radiation on the development of H. asiaticum substantially depends on the frequency of microwave modulation of a signal and on the temperatures of an experiment. When the temperature is 22 degrees C, there is a significant suppression of development of fed larvae and nymphs after exposure to microwave radiation at modulated signal frequencies of 3 and 5 Hz/ The whole range of the tested modulation frequencies was 2 to 16 Hz. The hungry species of all developmental phases in H. asiaticum were virtually unresponsive to exposures. At 14 degrees C (a perithreshold temperature of H. asiaticum development), the action of microwave radiation changed from inhibitory to stimulating. At modulation frequencies of 3, 5 and 7 Hz, the proportion of hatching larvae was 42.5, 67.5 and 80.0%, respectively, and that of controls was 2.5%. Whether the size of a H.asiaticum population can be controlled by a radar that provokes the development of ticks before winter by its radiation is discussed.

Animals↗
PubMed1991

A cloned DNA probe identifies Cowdria ruminantium in Amblyomma variegatum ticks.

Heartwater, caused by Cowdria ruminantium and transmitted by ticks of the genus Amblyomma, is a constraint to ruminant animal production in sub-Saharan Africa. This rickettsial disease could spread from endemically infected areas of sub-Saharan Africa and certain Caribbean islands to other countries, including the United States, in which Amblyomma ticks exist. To detect C. ruminantium in tick vectors and animals, we made DNA probes from C. ruminantium DNA isolated from endothelial cell cultures. Two clones were evaluated; pCS20 from Crystal Springs (Zimbabwe) strain DNA had a 1,306-bp insert, and pCR9 from Kiswani (Kenya) strain DNA had a 754-bp insert. Both DNA probes detected 1 ng of Crystal Springs DNA; however, the pCS20 probe had a 10-fold-greater ability to discriminate between C. ruminantium DNA and DNA from other organisms. Also, the pCS20 probe did not hybridize to 400 ng (highest amount tested) of DNA from bovine cells, 3 protozoa, 3 rickettsiae, and 12 bacteria. In all experiments, C. ruminantium DNA was detected in midguts from 99 of 160 Amblyomma variegatum nymphs infected as larvae and in midguts from 38 of 80 adult ticks infected as nymphs but not in midguts from control nymphs and adults. The presence of C. ruminantium in nymphs and adults was confirmed by transmission of heartwater to goats. The DNA sequences of both probes were determined; synthetic oligonucleotides from pCS20 are recommended as DNA probes for C. ruminantium.

Animals↗
PubMed2004

OspB antibody prevents Borrelia burgdorferi colonization of Ixodes scapularis.

Borrelia burgdorferi outer surface protein OspB is expressed by spirochetes in the Ixodes scapularis gut. ospB is transcribed from a bicistronic operon with ospA, a known spirochete adhesion gene in the tick gut. Here we examine whether OspB also has a specific function in ticks. OspB specifically binds to a protein or protein complex within the tick gut. We also assessed whether selected nonborreliacidal OspB antibodies or F(ab)(2) fragments interfere with B. burgdorferi-tick attachment in vivo. We examined engorged ticks that fed on B. burgdorferi N40-infected scid mice that had been treated with OspB F(ab)(2) fragments. Control F(ab)(2) fragments did not interfere with B. burgdorferi colonization of the tick gut, whereas OspB F(ab)(2) fragments significantly inhibited the attachment of spirochetes to the tick gut. These studies show that nonbactericidal OspB antibodies interfere with B. burgdorferi colonization of I. scapularis, highlighting a specific role for OspB in spirochete- arthropod interactions and suggesting new antibody-mediated strategies for interfering with B. burgdorferi transmission.

Animals↗
PubMed1990

[Immunogenetic methods for predicting the clinical course of tick-borne encephalitis].

Distribution of HLA antigens, haplotypes and phenotypes of the histocompatibility complex was studied and compared in 110 patients with tick borne encephalitis, living in Novosibirsk. The disease patterns and varieties were many and varied. Distribution of HLA antigens in 140 healthy subjects also living in Novosibirsk served as control. Based on the results of the immunogenetic examination of patients with tick borne encephalitis, the methods were elaborated, enabling one to predict with a high accuracy of probability the development of the feverish, meningeal or focal forms of tick borne encephalitis, one- or two-wave disease variety within the first days of disease. Concurrent analysis of the sex of the person bitten by the virulent tick and combination in one genotype of several allelic forms of the main histocompatibility complex genes allows one to raise appreciably the prognostic significance of the immunogenetic examination and to elaborate high-informative individual diagnostic criteria.

Adolescent↗
PubMed1993

Preliminary analysis of the transmission dynamics of Theileria parva in eastern Africa.

Two mathematical models are developed that investigate the transmission dynamics of Theileria parva by the ixodid tick Rhipicephalus appendiculatus to cattle in endemically stable areas. A method of estimating the rate of infection to cattle of T. parva at the endemically stable state is given. Empirical estimates of all the parameters in the model are available. The degree to which animals that have recovered from theileriosis (the 'carrier' state) are able to transmit the infection to tick nymphs or larvae is a crucial determinant of the dynamics of infection in a herd. Two control methods influencing the transmission of infection are considered--infection and treatment immunization and the reduction in tick feeding by acaricide application. The impact of each method on the transmission of infection is evaluated. Future developments and the data required to predict the dynamics of T. parva infections in cattle and ticks are discussed.

Africa, Eastern↗
PubMed1996

Selective inhibition of factor Xa is more efficient than factor VIIa-tissue factor complex blockade at facilitating coronary thrombolysis in the canine model.

OBJECTIVES: We determined the effect of adjunctive inhibition of the extrinsic coagulation pathway by factor VIIa-tissue factor complex inhibitors, DEGR VIIa and tissue factor pathway inhibitor (TFPI), and the selective factor Xa inhibitor, tick anticoagulant peptide (TAP), after thrombolytic therapy with tissue-type plasminogen activator (t-PA) in a canine model of electrically induced coronary thrombosis. BACKGROUND: Ongoing thrombin generation is considered an important component of the heightened thrombin activity associated with thrombolytic therapy and may be responsible for reperfusion failure and reocclusion. METHODS: Forty-two dogs with electrically induced coronary thrombus undergoing thrombolysis with t-PA (1 mg/kg over 20 min) were randomly assigned to one of the following adjunctive regimens: TAP (30 micrograms/kg body weight per min for 90 min, n = 10); TFPI (100 to 150 micrograms/kg per min for 90 min, n = 10); DEGR VIIa (1- to 2-mg/kg bolus, n = 10) and saline control (n = 12). The dogs were observed for 120 min after thrombolysis for reocclusion. RESULTS: All three active study agents accelerated the time to reperfusion by an average of 12 min (all p < 0.05). Duration of reflow was greatest with TAP (117 +/- 8 min, p < 0.05 compared with saline control), whereas DEGR VIIa and TFPI did not prolong the duration of reflow. Reocclusion rates were similar among control, DEGR VIIa and TFPI groups (70%, 78% and 67%, respectively). Tick anticoagulant peptide reduced the occurrence of reocclusion (0%, p < 0.05 compared with saline control). CONCLUSIONS: In this experimental model, during systematic blockade of various extrinsic coagulation pathway proteins, we demonstrated that whereas acceleration of thrombolysis occurs with factor VIIa-tissue factor complex inhibition, optimal enhancement of thrombolysis was achieved through specific factor Xa blockade.

Animals↗
PubMedDate not supplied

[Epidemiological surveillance on natural-borne infections in the Ulyanovsk region].

The analysis of natural foci of haemorrhagic fever with renal syndrome (HFRS) and tick-borne borreliosis on the territory of the Ulyanovsk region is presented. Reduced rat control interventions result in a wide spread of these and other infections with natural focality. Monitoring of natural foci of HFRS, tick-borne borreliosis and arbovirus infections, their typing and determination of main reservoirs are the most promising among epidemiological surveillance methods.

Animals↗
PubMed1990

How can i avoid lyme disease? What to say to the patient who asks.

No magic bullet for eliminating or medical breakthrough for preventing Lyme disease can be seen on the horizon. This fast-growing pandemic, second only to acquired immunodeficiency syndrome in public interest and concern, will probably continue to increase in range and incidence for the foreseeable future. Ticks are notoriously difficult to thwart, but intelligent application of control measures may be effective. More important, commonsense safety measures offer personal protection to the degree that they are assiduously practiced.

Animals↗
PubMedDate not supplied

[Reactogenicity and immunological effectiveness of a concentrated, purified vaccine against tick-borne encephalitis].

Human reactogenicity and immunological efficacy of concentrated purified tick-borne encephalitis (CTBEV) vaccine was studied in a controlled trial. The new vaccine was found to be superior to the commercial preparation in its capacity to induce specific humoral and cell-mediated immunity in man and in reduced sensitizing activity with regard to nonviral cellular antigens. Two vaccinations with CTBEV in doses of 0.5 ml each at 6-month interval are recommended. At this vaccination schedule virus neutralizing antibodies were detectable in 95% vaccines. Inoculation of 0.5 ml CTBEV is accompanied by fever of mild and moderate intensity in 19% and 3% of the vaccines, respectively. In this respect CTBEV is less reactogenic than the commercial preparation.

Adolescent↗
PubMed2001

Laboratory and field investigations into the Theileria parva carrier-state in cattle in Zimbabwe.

The Theileria parva carrier-state in cattle on commercial farms on Zimbabwe was investigated using parasitological and serological methods. The proportion of cattle showing Theileria piroplasms on two farms, which had recent histories of disease outbreaks, were 64% (n = 106, total of heifers and weaned calves examined) and 71.5% (n = 60) while the proportion of T. parva antibodies for the same animals were 59% and 98.5%, respectively. On four farms where no cases of the disease occurred for over 10 years, the average proportion of animals showing piroplasms and antibodies were 55.4% (range 32-82, n = 223) and 73% (range 47-91, n = 223), respectively. However, on another three farms which had no history of theileriosis outbreaks these proportions were very low, being 11.4% (0-24, n = 157) for piroplasms and 12.2% (5-23, n = 157) for antibodies. The mean infection rate in unfed Rhipicephalus appendiculatus adults collected from farms with a high prevalence of cattle which were carriers of Theileria piroplasms during the tick activity season was 29% (range 12-60%) with 9.3 (range 2-18.7) mean infected acini per infected tick. The infectivity of different tick batches to susceptible cattle produced a wide spectrum of theileriosis reactions. Laboratory controlled experiments were carried out to study the persistence of T. parva (Boleni) piroplasms in cattle immunized with this strain as well as its infectivity for ticks and its subsequent transmissibility to cattle. Examination of the salivary glands of 15 batches of ticks collected from six immunized cattle on three different occasions over 18 months showed that none were infected with Theileria parasites. However, the infectivity of other ticks in the same batches to susceptible animals was demonstrated 6, 10 and 18 months after cattle had been immunized with Boleni stabilate.

Animals↗