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At least 1,603 records · Page 89Linked to original sources
PubMed1995

Recombinant OspA protects dogs against infection and disease caused by Borrelia burgdorferi.

Twenty-two specific-pathogen-free beagles were vaccinated with recombinant OspA (ospA gene derived from Borrelia burgdorferi B31) alone or with adjuvant (QuilA, Montanide ISA25, or aluminum hydroxide) at 6 weeks of age. Thirteen dogs were used as nonvaccinated controls with or without adjuvant. Three dogs were kept as contact controls and received neither vaccine nor challenge. Six weeks or 6 months after the first vaccination, the vaccinated (20 of 22) and nonvaccinated dogs (13) were challenged by exposure to adult ticks (Ixodes scapularis) naturally that were infected with B. burgdorferi (tick infection rate, > or = 60%) and that were collected from Westchester County, N.Y. Protection from infection was evaluated by culture for B. burgdorferi from skin biopsies taken near the sites of tick bites. Skin biopsies were taken at monthly intervals for 3 months. B. burgdorferi was not isolated from any of the vaccinated dogs. In contrast, 12 of 13 control dogs challenged by exposure to the ticks were culture positive. The histopathology of the joint capsules 3 months after the challenge was used to evaluate protection from arthritis. Eight of 13 control dogs showed synovitis in single or multiple joints, while only 1 of the 22 vaccinated dogs had a single focus of mild inflammation in a single joint. At the time of the challenge, the vaccinated dogs had antibody to B. burgdorferi, which was demonstrable by kinetic enzyme-linked immunosorbent assay, Western blotting (immunoblotting), and a serum growth inhibition assay. The vaccinal antibody declined gradually after the challenge, especially in dogs vaccinated with OspA without adjuvants. Antibodies in the challenge control dogs were only detectable by 4 to 6 weeks after the challenge and remained at high levels until the termination of the study. Contact control dogs showed no antibody responses or histopathologic lesions and were culture negative. By Western blot analysis, antibodies to OspA first appeared in the sera of vaccinated dogs 3 weeks after the first vaccination. The absence of additional bands after the challenge suggests that infection in vaccinated dogs was blocked. Results from this study show that vaccination with recombinant OspA protected dogs against infection and disease after an experimental challenge with B. burgdorferi by exposure to ticks.

Animals↗
PubMedDate not supplied

Biological and clinical responses of west African sheep to Crimean-Congo haemorrhagic fever virus experimental infection.

West African sheep appear to play a central role as virus hosts in the maintenance cycle of Crimean-Congo haemorrhagic fever (CCHF) virus in endemic areas and also because of their role as a principal host of the CCHF virus tick vector. In an effort to clarify CCHF epidemiological significance in sheep, we studied the biological and clinical aspects of sheep experimentally infected with CCHF virus. West African sheep breeds were infected either by intraperitoneal inoculation or by infestation with experimentally CCHF-virus-infected ticks (Hyalomma truncatum). A total of 17 sheep including controls as well as 5 lambs from their progeny were monitored. A moderate but constant fever was observed (39.7 degrees C +/- 0.3) which correlates with the viraemia. Virus was reisolated from blood samples taken from day 3 to day 9 postinfection (p.i.) at a mean titre of 3.3 log LD50/ml. The virus was detected for a period of time of 7 days in non-immune sheep and for less than 4 days in previously immunized sheep. In non-immune sheep, antibody detected by ELISA showed an IgM response on day 7 p.i., followed by an IgG response one day later. Five infected sheep, surveyed for liver and kidney biological markers, showed hepatic dysfunction with a moderate serum aspartate transferase rise to 210 U/l. Out of four sheep tested for blood markers, two showed an abnormal blood cell count, with marked neutrophilia of up to 63% lasting for two weeks. Infected pregnant ewes produced antibodies in their milk at a significant titre (1:1,000), and antibodies were recovered in the sera of nursing lambs from their first meal to 50 days after birth. These findings are discussed; they demonstrate that, in spite of a high turnover of local sheep herds (median age of 3 years) and long-term CCHF antibody persistence (> 3 years), sheep can be infected and efficiently transmit the virus at least once in a lifetime.

Africa, Western↗
PubMed1996

Environmental and life-style risk factors for Lyme disease in children.

Risk factors for Lyme disease and/or infection with Borrelia burgdorferi in children are not defined. A case-control study was performed using Lyme disease patients from our Lyme Clinic population. Age- and sex-matched controls from the same neighborhood were identified by the Lyme patients' families. A site visit was made to each case/control neighborhood. Twenty-four environmental variables, especially the ecologic characteristics of the home environment were examined. Forty-five items were surveyed by parent questionnaire, including certain "high-risk" activities and behaviors, whether ticks or certain animals were present on the property, and whether antitick measures were used. Control subjects had serologic assays for antibodies to B. burgdorferi. Forty-four Lyme disease patients and 44 well-matched control subjects participated; 2 controls were seropositive. Significant associations with Lyme disease were found for deer ticks in the home environment, ground cover containing moist humus, and leaf litter in the yard. Among the 45 items related to life-style, there was no correlation with Lyme disease for the use of any antitick measures or for any childhood activities; in fact, an inverse correlation was observed for camping and fishing. We conclude that conditions in the immediate home environment, including certain ecologic factors that favor the presence of Ixodes ticks, are associated with an increased risk for Lyme disease in children.

Adolescent↗
PubMed2003

Treatment of external and internal parasites of cattle.

To control parasitic disease in cattle, one first has to determine what parasites he or she is trying to control--nuisance and biting flies in a milking parlor or ticks on range cattle? The determination may be based on geographic location, class of cattle, and their management. After determining what is there, then if the numbers are sufficient, justify treatment. Each livestock producer has a different array of parasites with which to deal, and in some circumstances, parasitic disease is below the economic threshold. Others may have occasional clinical disease associated with parasites, but most have situations in which the potential of economic loss is high enough to justify control.

Animal Husbandry↗
PubMed1997

Human granulocytic ehrlichiosis in southern Germany: increased seroprevalence in high-risk groups.

To date, human granulocytic ehrlichiosis (HGE), the causative agent of which is likely transmitted by ticks in the Ixodes ricinus-Ixodes persulcatus complex, has not been diagnosed with certainty in patients outside the United States. The presence of a closely related vector tick, I. ricinus, as well as the occurrence of similar Ehrlichia spp. of veterinary importance, suggests that this disease is likely to be present in Europe. The aim of the present study was to compare the prevalence of antibodies against the HGE agent in sera collected from patients in groups at high risk for exposure to I. ricinus with that of a control population. Risk groups consisted of 150 forestry workers and 105 patients with an established diagnosis of Lyme disease. The control group was 103 healthy blood donors without a history of tick bites. We used a patient isolate of the HGE agent from Minnesota (J. L. Goodman, C. Nelson, B. Vitale, J. E. Madigan, J. S. Dumler, T. J. Kurtti, and U. G. Munderloh, N. Engl. J. Med. 334:209-215, 1996) propagated in HL60 cells as the source of antigen for a specific immunofluorescence assay (IFA). Elevated IFA titers (> or = 1:80) were present in 21 of 150 (14%) serum samples from forestry workers and in 12 of 105 (11.4%) serum samples from Lyme disease patients, but in only 2 of 103 (1.9%) serum samples from blood donors (P < or = 0.01 for either of the at-risk groups versus blood donors). The results of this study suggest that the HGE agent or a closely related organism exists in southern Germany and that seroconversion to it is common among groups exposed to Ixodes ticks. Final proof that HGE occurs in Germany will require the isolation of the causative agent from patients. HGE should be considered in the differential diagnosis of febrile illnesses in individuals exposed to Ixodes ticks in Europe as well as in North America.

Animals↗
PubMed2002

Behaviour, chemosignals and endocrine functions in male mice infected with tick-borne encephalitis virus.

Odour attractiveness, social behaviour and endocrine status of male mice (outbred ICR strain) were examined 6-7 days after inoculation with subclinical dose of tick-borne encephalitis virus (TBE). According to RT-PCR control of efficiency of infection, males injected with TBE were divided on the two subgroups: TBE+ (males with viral RNA) and TBE- (males without viral RNA). Susceptible males (TBE+ subgroup) showed the higher level of plasma testosterone in comparison with both control and nonsusceptible (TBE- subgroup) males. TBE+ males had also more odour attraction for oestrus females and more aggressiveness in social conflict. Higher sexual attractiveness and aggressiveness of the infected host benefit the pathogen's distribution in the host population.

Aggression↗
PubMed2000

Leptospirosis in Kuala Lumpur and the comparative evaluation of two rapid commercial diagnostic kits against the MAT test for the detection of antibodies to leptospira interrogans.

The aim of the study was to look into the epidemiology of serodiagnosed cases of leptospirosis at the University Hospital and compare two commercial ELISA Assays to the Microscopic Agglutination Test (MAT). Demographic data for all serodiagnosed cases for the years 1991-1997 were collected. From this data, 104 sera (n = 104) were selected as samples for comparative evaluation of the commercial ELISAs (INDX Dip-S-Ticks and PanBio ELISA) to the MAT test. Thirty two (n = 32) negative control sera were selected from serodiagnosed cases of other differential diagnosis of leptospira infection. The MAT test is a standard test that detects agglutination antibodies to leptospira biflexa, while the INDX Dip-S-Ticks is an ELISA dot test assaying for total anti-leptospira antibodies. The PanBio ELISA is a colorometric assay in test well strips to detect anti-leptospira IgM. The sensitivity, specificity, and efficiency of tests were calculated at a MAT cut-off value of 1:320. Demographic data showed that leptospirosis peaks during March-May and Aug-Nov coinciding with the inter-monsoon period with more men being infected than women and more adults than children. The sensitivity, specificity, and efficiency of test for the INDX Dip-S-Ticks were 83.3%, 93.8% and 87.5% while the values for the PanBio ELISA were 54.2%, 96.9% and 71.3%. The suboptimal PanBio result could be related to the blocking effect of high IgG titres or could be related to the diagnostic MAT cut-off values used in this study. The data hence reflects a pattern of transmission that is related to "wet" occupational risk factors. The commercial assays evaluated, are easier to perform but interpretation of results should be based on level of endemicity. The INDX Dip-S-Ticks allows this flexibility and is a practical alternative to the MAT test.

Adult↗
PubMed2002

Reactivity of serum samples from patients with a flavivirus infection measured by immunofluorescence assay and ELISA.

Flavivirus infections are a significant public health problem, since several members of the Flaviviridae family are highly pathogenic to humans. Accurate diagnosis and differentiation of the infecting virus is important, especially in areas where many flaviviruses are circulating. In this study we evaluated a newly developed commercially available immunofluorescence assay (IFA) (INDX, Baltimore, MD, USA) for the detection of IgM and IgG antibodies against dengue virus, yellow fever virus, Japanese encephalitis virus and West Nile virus. IFA was compared with standard diagnostic enzyme immunoassays (EIAs) specific for the detection of IgM and IgG antibodies against these viruses. Forty-seven serum samples from patients with a defined flavivirus infection were tested. As controls, serum samples from individuals with antibodies against tick-borne encephalitis virus and hepatitis C virus as well as healthy individuals were included. The results obtained from this study indicate that IFA showed a significantly better discrimination for flavivirus specific IgM antibodies than did the standard IgM specific EIAs (the overall cross-reactivity varied between 4 and 10% by IFA and 30-44% by EIA for the respective viruses). In contrast, the detection of flavivirus specific IgG antibodies showed high cross-reactions in both IFA and EIAs (overall cross-reactivity 16-71 and 62-84%, respectively). This study clearly stated the complexity of flavivirus diagnosis, showing that one cannot rely on one assay or search for one virus only. The flavivirus IFA is a useful tool for the identification of flavivirus infections during the acute stage of disease. In particular, IFA can be an important diagnostic tool for testing samples from travellers who have been accidentally exposed to these viruses.

Antibodies, Viral↗
PubMed2001

Impact of a computer-based auto-tutorial program on parasitology test scores of four consecutive classes of veterinary medical students.

A "Hard and Soft Tick" auto-tutorial that integrates basic knowledge of the parasite biology with practical aspects of tick identification, clinical presentation, pathology, disease transmission, treatment, and control was developed at the University of Wisconsin-Madison School of Veterinary Medicine. The purpose of this study was to assess impact of the auto-tutorial on parasitology test scores in four classes (1999, 2000, 2001, and 2002) of veterinary students. The analysis revealed a small but significant increase (p = 0.054) in mean percentage examination scores for students who used the tutorial over those who did not.

Computer-Assisted Instruction↗
PubMed2002

Lyme disease--United States, 2000.

Lyme disease (LD) is caused by the tickborne spirochete Borrelia burgdorferi sensu lato and is the most common vectorborne disease in the United States. CDC initiated LD surveillance in 1982, and the Council of State and Territorial Epidemiologists designated it a nationally notifiable disease in 1991. This report summarizes the 17,730 cases of LD reported to CDC during 2000, which indicates that more LD cases were reported in 2000 than in any previous reporting year and that the reported incidence of LD is greatest in the northeastern, mid-Atlantic, and north-central regions of the United States. LD can be prevented by reducing tick populations, avoiding tick-infested habitats, using repellents, promptly removing attached ticks, and vaccination.

Humans↗
PubMed1987

Antibodies define multiple proteins with epitopes exposed on the surface of live Babesia bigemina merozoites.

Babesia bigemina is one of several tick-borne hemoparasitic diseases of cattle that are inadequately controlled and cause substantial livestock production losses in tropical and subtropical climates. Recovery from acute babesiosis is associated with development of protective immunity against subsequent challenge with both homologous and heterologous parasites. Viable and infectious merozoites, the intraerythrocytic stage of B. bigemina responsible for clinical disease, were separated from contaminating host cells by density gradient centrifugation. Monoclonal antibodies developed against gradient-separated merozoites were screened for surface reactivity against live merozoites in an immunofluorescent binding assay. Surface-reactive antibodies immunoprecipitated five major biosynthetically radiolabeled merozoite proteins with relative m.w. of 72,000, 58,000, 55,000, 45,000, and 36,000 in SDS-PAGE. Two additional proteins immunoprecipitated with the 45,000 m.w. protein were unreactive with monoclonal antibody in western blots and are apparently part of a membrane complex co-precipitated by this antibody. In contrast, additional proteins of m.w. of 36,000, 35,000, and 33,000, immunoprecipitated with the 58,000 protein, all contain the surface-exposed epitope bound by monoclonal antibody. Immune serum from an animal that had recovered from infection with a Mexico isolate of B. bigemina immunoprecipitated five radiolabeled proteins from the Mexico isolate that co-migrated in SDS-PAGE with major proteins precipitated by surface-reactive monoclonal antibodies. In addition, antibodies against a Kenya isolate of B. bigemina immunoprecipitated the same co-migrating proteins from radio-labeled Mexico isolate, demonstrating epitope conservation between surface proteins of geographically different isolates. The identification of proteins with epitopes exposed on the surface of live merozoites and accessible to antibody provides candidates to be tested as protective immunogens in cattle.

Animals↗
PubMed2000

Absence of insect juvenile hormones in the American dog tick, Dermacentor variabilis (Say) (Acari:Ixodidae), and in Ornithodoros parkeri Cooley (Acari:Argasidae).

Synganglia, salivary gland, midgut, ovary, fat body and muscle alone and in combination from the ixodid tick, Dermacentor variabilis (Say), or the argasid tick, Ornithodoros parkeri Cooley, were incubated in vitro in separate experiments with L-[methyl-(3)H]methionine and farnesoic acid or with [1-(14)C]acetate. Life stages examined in D. variabilis were 3 and 72 h old (after ecdysis) unfed nymphs, partially fed nymphs (18 and 72 h after attachment to the host), fully engorged nymphs (2 d after detachment from host), 3 and 72 h old (after eclosion) unfed females, partially fed unmated females (12-168 h after attachment to host) and mated replete females (2 d after detachment from the host). Those from O. parkeri were third and fourth stadium nymphs and female O. parkeri, 1-2 d after detachment. Corpora allata from Diploptera punctata, Periplaneta americana and Gromphadorina portentosa were used as positive controls in these experiments. No farnesol, methyl farnesoate, JH I, JH II, JH III, or JHIII bisepoxide was detected by radio HPLC from any tick analysis while JH III, methyl farnesoate, and farnesol were detected in the positive controls. To examine further for the presence of a tick, insect-juvenilizing agent, Galleria pupal-cuticle bioassays were conducted on lipid extracts from 10 and 15 d old eggs, unfed larvae (1-5 d after ecdysis), unfed nymphs (1-7 d after ecdysis), and partially fed, unmated female adults (completed slow feeding phase) of D. variabilis. Whole body extracts of fourth stadium D. punctata and JH III standard were used as positive controls. No juvenilizing activity in any of the tick extracts could be detected. Electron impact, gas chromatography-mass spectrometry of hemolymph extracts from fed, virgin (forcibly detached 7 d after attachment) and mated, replete (allowed to drop naturally) D. variabilis and fully engorged (1-2 d after detachment) O. parkeri females also failed to identify the common insect juvenile hormones. The same procedures were successful in the identification of JH III in hemolymph of fourth stadium D. punctata. Last stadium nymphal (female) O. parkeri implanted with synganglia from second nymphal instars underwent normal eclosion to the adult. The above studies in toto suggest that D. variabilis and O. parkeri do not have the ability to make the common insect juvenile hormones, and these juvenile hormones do not regulate tick metamorphosis or reproduction as hypothesized in the literature.

Journal Article↗
PubMed2004

Imported spotted fever rickettsioses in United States travelers returning from Africa: a summary of cases confirmed by laboratory testing at the Centers for Disease Control and Prevention, 1999-2002.

The increasing popularity of foreign travel and ecotourism places travelers at increased risk for certain tick-borne diseases. From 1999 through 2002, 31 cases of imported spotted fever-group rickettsioses (SFGR) in United States residents reporting travel to Africa were confirmed by laboratory testing at the Centers for Disease Control and Prevention. Nineteen patients (61%) reported visiting South Africa prior to illness onset. Most patients reported fever and one or more eschars; rash was reported for only 26% of the patients. Twelve patients had an initial non-reactive acute-phase serum sample obtained a median of three days after illness onset, and were confirmed by testing a second convalescent-phase serum sample obtained a median of 32 days after illness onset. Five patients were confirmed positive through immunohistochemical staining of skin biopsies, including three patients with acute-phase serum samples that tested negative for SFGR. This study emphasizes the importance of evaluating convalescent-phase serum specimens 28 days or more after illness onset or examining skin biopsies by immunohistochemical staining during early infection to confirm a diagnosis of imported SFGR.

Africa↗
PubMed1979

Epizootiology and control of anaplasmosis in south africa.

The history of bovine anaplasmosis, or tick-born gallsickness, since the discovery of Anaplasma marginale by Sir Arnold Theiler is briefly reviewed. The development of the Anaplasma centrale vaccine by Theiler, up to the composition of the present vaccine issued by Onderstepoort in which the original isolate is still passaged, is discussed in detail. Recent transmission studies at Onderstepoort have shown that 5 tick species are capable of transmitting anaplasmosis intrastadially, and intrastadial transmission, especially by adult male ticks, it is believed, could play an important role in the epizootiology of bovine anaplasmosis in South Africa. Disease incidence and tick distribution are discussed in relation to enzootic and epizootic conditions. Investigations have proved that the Onderstepoort A. centrale vaccine is not as avirulent in adult cattle as it was previously thought to be. The results of a field trial undertaken to test the infectivity of the vaccine, are given.

Anaplasma↗
PubMed2005

Cuticle-induced endo/exoacting chitinase CHIT30 from Metarhizium anisopliae is encoded by an ortholog of the chi3 gene.

The characterization of chitinase genes and enzymes is an important step toward global understanding of the chitinolytic system in entomopathogenic fungi. Chitinase CHIT30 from Metarhizium anisopliae var. anisopliae (strain E6) has both endo- and exochitinase activities and is a potential determinant of pathogenicity. Serum anti-CHIT30 specifically detected this chitinase amongst five isoenzymes shown in glycol-chitin activity gels. Chitinase CHIT30 secretion is upregulated by chitin, tick cuticle and low concentrations of N-acetylglucosamine (0.25%) and is downregulated by both high N-acetylglucosamine (1%) and glucose (1%) concentrations. Chitinase CHIT30 was produced at tick cuticle during fungal infection. The chi3 gene was assigned to code chitinase CHIT30 in M. anisopliae var. anisopliae.

Amino Acid Sequence↗
PubMed2003

Case-control study of canine infection by a newly recognised Babesia microti-like piroplasm.

We did a case-control study to identify risk factors for prevalent infection of dogs by a newly recognised Babesia microti-like piroplasm. Clinical manifestations and haematology of infected dogs also were described. Forty-three laboratory-based cases and 86 individually matched controls were studied. Information on clinical signs and on risk factors was collected by a questionnaire and telephone interviews. Haematology was carried out for all the dogs. Variables were screened in a bivariable conditional logistic regression and checked for colinearity. The final multivariable model was selected by backward stepwise elimination. The odds of a case having ticks when examined at the clinic was 4 times that of a control and the odds of a case being a hunting or a house-guarding dog were, respectively, 24.2 and 2.7 times those of a control. The most consistently reported clinical signs were weakness (79%), tachycardia (43%) and haemoglobinuria (42%). Mean red-blood-cell count, haemoglobin concentration, platelet count, and mean platelet volume of infected dogs were lower than the reference values and those of non-infected dogs-but leukocyte count, mean corpuscular volume and red-blood-cell distribution width were higher.

Animal Husbandry↗