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At least 1,621 records · Page 90Linked to original sources
PubMed2004

[Immunization recommendations for travel in the Mediterranean area].

The Mediterranean region is a popular destination for tourists during the summer. However, European tourists, who are travelers within their own continent, do not consider themselves exposed to possible, travel-associated infections, since problem awareness among tourists as well as doctors is rather weak. The objective of this consensus paper is to outline guidelines with regard to relevant travel immunizations for Mediterranean destinations. These recommendations are mainly based on risk calculations according to country-specific incidences and prevalences of vaccine-preventable diseases such as hepatitis A, hepatitis B, typhoid fever, meningococcal meningitis, rabies, and tick-borne encephalitis.

Animals↗
PubMed1990

[The prevalence of Borrelia burgdorferi antibodies in a population at risk].

Given the increasing interest in Lyme borreliosis in our community, and the lack of epidemiological studies in our country, we have considered convenient to analyze the presence of anti-Borrelia burgdorferi antibodies in a group of workmen who we have considered at high risk since they carry out their everyday work in an environment infested by ticks. Significant antibody titers (= or greater than 1/128) are found in 38% of cases versus 0% in the control group. The significance of these results in relation to the presence or not of compatible clinical manifestations and tick bites are studied.

Agricultural Workers' Diseases↗
PubMed2004

African swine fever virus multigene family 360 genes affect virus replication and generalization of infection in Ornithodoros porcinus ticks.

Recently, we reported that African swine fever virus (ASFV) multigene family (MGF) 360 and 530 genes are significant swine macrophage host range determinants that function by promoting infected-cell survival. To examine the function of these genes in ASFV's arthropod host, Ornithodoros porcinus porcinus, an MGF360/530 gene deletion mutant (Pr4Delta35) was constructed from an ASFV isolate of tick origin, Pr4. Pr4Delta35 exhibited a significant growth defect in ticks. The deletion of six MGF360 and two MGF530 genes from Pr4 markedly reduced viral replication in infected ticks 100- to 1,000-fold. To define the minimal set of MGF360/530 genes required for tick host range, additional gene deletion mutants lacking individual or multiple MGF genes were constructed. The deletion mutant Pr4Delta3-C2, which lacked three MGF360 genes (3HL, 3Il, and 3LL), exhibited reduced viral growth in ticks. Pr4Delta3-C2 virus titers in ticks were significantly reduced 100- to 1,000-fold compared to control values at various times postinfection. In contrast to the parental virus, with which high levels of virus replication were observed in the tissues of infected adults, Pr4Delta3-C2 replication was not detected in the midgut, hemolymph, salivary gland, coxal gland, or reproductive organs at 15 weeks postinfection. These data indicate that ASFV MGF360 genes are significant tick host range determinants and that they are required for efficient virus replication and generalization of infection. The impaired virus replication of Pr4Delta3-C2 in the tick midgut likely accounts for the absence of the generalized infection that is necessary for the natural transmission of virus from ticks to pigs.

African Swine Fever↗
PubMed2006

Characterization of Haemaphysalis longicornis recombinant cement-like antigens and preliminary study of their vaccination effects.

Two genes encoding immunodominant antigens, hlim2 and hlim3, were obtained from a salivary gland cDNA library of the hard tick, Haemaphysalis longicornis. The recombinant proteins were expressed in Escherichia coli as the GST fusion protein and used for immunization. We observed that the attachment rate of nymphal ticks fed on mice immunized with GST-hlim3 was significantly lower than that in the control group during the initial days of feeding. However, immunization with GST-hlim3 did not affect the engorgement rate of the ticks. In sharp contrast, GST-hlim2 did not influence the attachment rate and feeding period of ticks but had a significant reduction in the engorgement body weight. These data highlight the suitability of the 2 recombinant cement-like proteins for use in a cocktail vaccine.

Amino Acid Sequence↗
PubMed2002

[Connection between severity of the course of tick-borne encephalitis with the concentration of interleukin-2 and interleukin-6 in blood].

AIM: To test IL-6 and IL-2 serum concentrations as indirect prognostic indicators in tick-borne encephalitis (TBE) course. MATERIAL AND METHODS: 13 TBE patients' sera were examined for IL-2 and IL-6. RESULTS: IL-6 was not detected in patients with TBE fever but was detected in meningoencephalytic TBE. CONCLUSION: TBE patients demonstrate a positive correlation between the disease severity and serum IL-6. This criterion is proposed as a prognostic factor of a TBE course.

Adult↗
PubMedDate not supplied

[Residual neurovirulence of the chimera of Langat and Denge-4 flaviviruses in intracerebral infection of monkeys].

The residual neurovirulence of the previously obtained chimeric virus Tp21/DEN4, containing the RNA region encoding the pre M and E structural enzymes, strain Tp21, virus Langat, and the remaining part of the genome from the Denge 4 virus, was studied in experiments with monkeys Cercopithecus aethiops involving the intracerebral administration of the virus. The tick-borne encephalitis virus, strain Absettarov, was used as positive control. A comparative analysis of the experimental and published data showed the chimeric virus to be less virulent by its degree of morphological affection in the CNS zones, its spread into the CNS and by a percentage share of animals with viremia versus the Tp21 parent strain and Elantsev strain of the Langat virus.

Animals↗
PubMed1978

Methods to improve the health of cattle in the tropics: conclusions and economic appraisal.

The results of the immune responses of immunised and chemoprophylactically treated calves to tick-borne (Boophilus microplus) challenge indicate that the system of immunisation was effective in protecting cattle against Anaplasma marginale, Babesia argentina (bovis), and B. bigemina. However, chemoprophylaxis was effective only against Babesia spp. but not against A. marginale. Both methods showed a substantial advantage over no control system when using native cattle breeds in a zone endemic for bovine anaplasmosis and babesiosis. Based on the net economic gain per calf starting the experiment, sizeable differences were noted at 308 days between the calves in the immunised group, chemoprophylaxis group, tick and gastrointestinal parasite control group and the experiment control group.

Anaplasmosis↗
PubMed1997

Conventional vaccines for tick-borne haemoparasitic diseases of sheep and goats.

Of the many tick-borne haemoparasites of sheep and goats, three may be controlled by vaccination. A live virulent blood vaccine for Cowdria ruminantium infection (heartwater) is used widely in southern Africa in an infection and treatment procedure. A live vaccine for Babesia ovis attenuated by passage in splenectomised sheep has been used extensively in Bulgaria with good results. A live vaccine for Theileria hirci, consisting of schizonts propagated in a lymphoid cell culture and attenuated by passage, has been used successfully in the Middle East.

Anaplasmosis↗
PubMed2004

An in vitro larval immersion microassay for identifying and characterizing candidate acaricides.

We have optimized a larval immersion microassay (LIM) that offers superior sensitivity, flexibility to accommodate multiple formulations, and a robust capability for rapidly screening many compounds with a minimal requirement of test article for evaluation. Dose-response studies were conducted for representative members from the organophosphate, pyrethroid, pyrazole, carbamate, macrocyclic lactone, and formamidine chemistries against Amblyomma americanum (L.). Time-response experiments revealed that permethrin was the most rapid acting, whereas fipronil had the slowest speed-of-kill against A. americanum. Comparison of drug susceptibility profiles between multiple ixodid ticks suggests that A. americanum is an effective model for predicting compound potency against Boophilus spp. in this bioassay. The LIM is suitable for the identification and characterization of active molecules from small- and medium-sized compound or natural product libraries, and it can be a useful tool to prioritize molecules for further in vivo testing in animal models.

Animals↗
PubMed1998

Production effects of cattle tick (Boophilus microplus) infestation of high yielding dairy cows.

Forty mid-lactation Holstein-Friesian cows, 100% lot fed, were assigned to four groups for 15 weeks. Two groups of 10 cows were infested each week with a gradually increasing number of Boophilus microplus larvae, while the other two groups were maintained free of ticks. Milk yield and composition (including somatic cell count, SCC), liveweight, dry matter intake, packed cell volume (PCV) and total plasma protein (TPP) were measured throughout the 15 week period. By week 15, control cows produced 2.86 l more milk and 0.14 kg more butterfat each day and had gained 10.6 kg more liveweight than infested cows. Each engorging female tick was estimated to be responsible for the loss of 8.9 ml of daily mild production and 1.0 g of bodyweight over the trial period. Milk composition, PCV and TPP were not significantly affected by cattle tick infestation. The dry matter intake of control cows was 0.83 kg greater than infested cows in week 12.

Animals↗
PubMed1990

An outbreak of suspected tick paralysis in one-humped camels (Camelus dromedarius) in the Sudan.

An outbreak of suspected tick paralysis occurred in one-humped camels in Southern Darfur, the Sudan, between latitudes 11-12 degrees N and longitudes 24-25 degrees E, when the camels were herded in tick infested areas. It involved 251 camels of different ages, in ten herds causing 34.3% mortality. The symptoms were incoordination of movements, unsteady gait and recumbency followed by death or recovery. Hyalomma adults and/or Rhipicephalus nymphs and adults were incriminated to be the cause of the disease. Transient paralysis in a guinea pig was produced after experimental feeding of ticks. Removal of the camels from the tick infested areas and treatment against the ectoparasites with Lindane at the concentration of 0.23% contributed to controlling the disease.

Animals↗
PubMedDate not supplied

[Expression of the NS1 gene of tick-borne encephalitis virus in gram-negative bacteria from the mouse nasopharynx].

Bacteria were isolated from the nasopharynx of BALB/c mice and electroporated with pUR290(NS1)2 containing two copies of tick-borne encephalitis virus (TBEV) strain Sofjin NS1 under the control of the lac promoter. The plasmid persisted in transformants for at least ten passages. The NS1 gene expression was detected in Gram-negative enterobacteria via immunoblotting with monoclonal antibodies against TBEV nonstructural glycoprotein NS1. Recombinant NS1 was detected in bacterial cells and in the culture medium. Intranasal immunization with recombinant bacteria activated production of antibodies against NS1 in serum of BALB/c mice. The humoral immune response to NS1 failed to protect immunized mice from a TBEV challenge.

Animals↗
PubMed1987

Protection of cattle against heartwater in Botswana: comparative efficacy of different methods against natural and blood-derived challenges.

Five groups of Tswana-cross castrated male cattle between 20 and 30 months of age (a total of 158 animals) were transported from a ranch in a heartwater-free area of south Botswana to a feedlot near Gaborone in the east of Botswana where heartwater is endemic. On arrival, one group was vaccinated intravenously with the Onderstepoort sheep blood heartwater vaccine, one group was vaccinated intravenously with the new Onderstepoort tick-derived heartwater vaccine and a third group was vaccinated subcutaneously with this tick-derived vaccine. Vaccine reactions were blocked with long acting oxytetracycline on the first day of fever. A fourth group had a series of injections of long acting oxytetracycline on days 0, 7, 14 and 21 after arrival, and a fifth served as untreated controls. The animals remained at the feedlot for 65 days during which time they faced a low level of challenge by Amblyomma hebraeum ticks. None contracted heartwater and so they were then challenged, together with a further group of control cattle, with a dose of the sheep blood vaccine. Some animals in all groups had severe heartwater reactions and died despite therapy, but 76.7 per cent, 64.5 per cent and 74.3 per cent of the cattle in the blood vaccine, intravenous tick vaccine and long acting oxytetracycline groups respectively were resistant to challenge, compared with 48.3 per cent of the subcutaneous tick vaccine group and 36.4 per cent of the controls. It was concluded that intravenous vaccination of susceptible adult cattle with either the blood or the tick-derived vaccine needs careful monitoring in the month after vaccination and does not necessarily result in immune animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Susceptibility of Ornithodoros parkeri (Cooley) (Acari: Argasidae) and Dermanyssus gallinae (DeGeer) (Acari: Dermanyssidae) to ivermectin.

Ivermectin was injected into hosts and evaluated for effectiveness against the argasid tick Ornithodoros parkeri (Cooley) and the chicken mite Dermanyssus gallinae (DeGeer). O. parkeri second stage nymphs (N2s) showed a marked increase in mortality when fed on mice injected intraperitoneally with ivermectin at a dose between 0.1 and 0.2 mg/kg host body weight. For adult O. parkeri and D. gallinae, 0.4 and 0.5 mg, respectively, per kilogram of host body weight were necessary for an increase in mortality over controls. These latter findings are comparable to those reported for other tick species but differ from those reported for the northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago). Further testing narrowed the effective dose range for O. parkeri adults to between 0.425 and 0.450 mg/kg host body weight. The time interval (4, 8, and 24 h) between ivermectin injection of the host and tick feeding had only a slight influence on the overall effectiveness of the drug. In O. parkeri, doses of 0.0125 to 0.1000 mg/kg body weight did not affect fecundity, hatchability, gross morphology of the reproductive system and synganglion, or histology of the reproductive system. Contrary to reports of irreversibility of effects of ivermectin on gamma aminobutyric acid-mediated neurotransmission, many ivermectin-paralyzed ticks recovered partial mobility over time.

Animals↗
PubMed2001

Interference between the agents of Lyme disease and human granulocytic ehrlichiosis in a natural reservoir host.

Agents of Lyme disease (Borrelia burgdorferi) and human granulocytic ehrlichiosis (Ehrlichia phagocytophila) are perpetuated in a natural cycle involving the black-legged tick (Ixodes scapularis) and its vertebrate hosts. Using I. scapularis nymphs as the mode of infectious challenge, we studied how infection with one pathogen in white-footed mice (Peromyscus leucopus) affects their ability to acquire the other agent and subsequently to infect larvae, which these agents would do in nature. Two groups of mice were infected with either B. burgdorferi or E. phagocytophila. One week later, B. burgdorferi-infected mice were challenged with E. phagocytophila, and E. phagocytophila-infected mice were challenged with B. burgdorferi. Simultaneously, two control groups of uninfected mice were infected with each agent from the same tick cohorts used on the first groups of mice. Uninfected I. scapularis larvae were fed on all mice for xenodiagnosis at weekly intervals lasting 2 months. For the B. burgdorferi challenge, all control and E. phagocytophila-infected mice acquired B. burgdorferi. However, fewer xenodiagnostic larvae acquired B. burgdorferi from mice with mixed infections compared with mice infected with B. burgdorferi only. For the E. phagocytophila challenge, all five control mice acquired E. phagocytophila, but only two of five mice infected with B. burgdorferi subsequently acquired E. phagocytophila. Consequently, mice with both infections produced fewer xenodiagnostic ticks infected with E. phagocytophila than mice infected with E. phagocytophila only. Thus, a primary infection with either B. burgdorferi or E. phagocytophila in mice inhibited transmission of a second agent, suggesting interference between these two agents.

Anaplasma phagocytophilum↗
PubMed1986

Efficacy of parvaquone and long-acting oxytetracycline in Theileria annulata infection.

Therapeutic and prophylactic efficacies of parvaquone and long-acting oxytetracycline were tested against Theileria annulata infection, induced by injecting a suspension of infected ground tick tissues (GUTS) into groups of 4 or 5 calves. This infection killed two of four control calves, while all the animals given a single intramuscular dose of 20 mg kg-1 parvaquone or long-acting oxytetracycline on the day of infection underwent mild reactions and recovered. Two separate doses of parvaquone of 10 mg kg-1 administered on the first and second days of fever protected four out of five calves. All the recovered animals from both treated and control groups resisted a homologous challenge with GUTS on Day 45 post-infection which killed three out of four susceptible unimmunized control calves.

Animals↗