Viable Borrelia burgdorferi in the urine of two clinically normal horses
Int J Med Microbiol. 2002 Jun;291 Suppl 33:80-7.
Horses and Borrelia: immunoblot patterns with five Borrelia burgdorferi sensu lato strains and sera from horses of various stud farms in Austria and from the Spanish Riding School in Vienna.
Muller I, Khanakah G, Kundi M, Stanek G.
Institute for Hygiene and Medical Microbiology of the University Vienna, Wien, Austria.
Grazing animals are continuously exposed to tick bites. Consequently, one may expect that horses will become infected with the various pathogens carried by ticks including Borrelia burgdorferi sensu lato. Whether horses may develop clinical disease due to this pathogen is controversially discussed. We were interested to learn about the infection of horses with Borrelia burgdorferi sensu lato within one season by studying the dynamics of the humoral immune response in paired blood samples. The majority of horses examined were Lipizzaner from the stud farm in Piber/Steiermark, and from the Spanish Riding School in Vienna. Smaller groups of animals of different breeds were from stud farms in Karnten, Niederosterreich, Salzburg and Steiermark. Clinical status and medical history were obtained and blood was drawn at the beginning of the highest tick activity and nine months later in 1998. Immunoblot technique (Western blot) was used in order to determine the dynamics in the immune response patterns. As antigens served the genospecies Borrelia afzelii, Borrelia burgdorferi sensu stricto, Borrelia garinii, Borrelia lusitaniae, and Borrelia valaisiana. 309 horses (age median 7 years, range 1/12 to 33 years) were seen at the first round. 186 of these animals (60.2%; median age 6 years, range 4/12 to 33 years) were re-examined in the second round. All animals were in normal health condition during both rounds of examination and blood sampling. Analysis of the immunoblot patterns was based on in-house-, Pko-, Pka2-, Pbi-, and European Union Concerted Action on Lyme Borreliosis (EUCALB) 2 & 3-criteria; analyses revealed a variety of positive results with different strains and criteria. Positive immunoblot results with 186 paired samples and B. afzelii as antigen, for example, ranged from 52 to about 91% in the first, and 53 to 93% in the second round. The age dependency analyses showed that the first infection with B. burgdorferi sensu lato occurs in the first year. Re-infection is characterised by appearance of additional bands. Continuously tick-exposed horses show a stable pattern of bands whilst in unexposed horses the number of bands decreases with age. In this study horses became repeatedly infected with B. burgdorferi sensu lato but, apparently, developed only rarely, if at all, clinical diseases. The infectious agent is predominantly B. afzelii. Antibodies to other borrelia genospecies are predominantly due to cross reactivity.
Prev Vet Med. 2001 May 1;49(3-4):191-208.
Cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. and demographic, clinical and tick-exposure factors in Swedish horses.
Egenvall A, Franzen P, Gunnarsson A, Engvall EO, Vagsholm I, Wikstrom UB, Artursson K.
Department of Ruminant Medicine and Veterinary Epidemiology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, P.O. Box 7019, SE-75007 Uppsala, Sweden.
agneta.egenvall@kirmed.slu.se
A cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. in Swedish horses was conducted to evaluate associations with demographic, clinical and tick-exposure factors. From September 1997-1998, blood samples from 2018 horses were collected from the animals presented to veterinary clinics affiliated with the Swedish Horserace Totalizator Board (regardless of the primary cause for consultation). Standardized questionnaires with information both from owners and attending veterinarians accompanied each blood sample. The apparent seroprevalences to B. burgdorferi s. l. and granulocytic Ehrlichia spp. were 16.8 and 16.7%, respectively. The northern region had the lowest seroprevalences. Four logistic models were developed (controlling for demographic variables). In the disease model of seropositivity to B. burgdorferi s. l., age, breed, geographic region, the serologic titer to granulocytic Ehrlichia spp., season and the diagnosis coffin-joint arthritis were significant. In the tick-exposure model of B. burgdorferi s. l., pasture access the previous year and gender were significant. Age, racing activity, geographic region, season and the serologic titer to B. burgdorferi s. l. were associated with positivity to granulocytic Ehrlichia spp. In the tick-exposure model of granulocytic Ehrlichia spp., pasture access was a risk factor. An interaction between racing activity and geographic region showed that the risk of positive serologic reactions to Ehrlichia spp. was increased in the horse population in the south and middle of Sweden, but only among horses not used for racing. Except for the positive association between coffin-joint arthritis and serologic reactions to B. burgdorferi s. l., there were no significant associations in the multivariable models between non-specific or specific clinical sign or disease with seropositivity to either of these agents.
J Am Vet Med Assoc. 2000 Oct 1;217(7):1045-50.
Serologic confirmation of Ehrlichia equi and Borrelia burgdorferi infections in horses from the northeastern United States.
Magnarelli LA, Ijdo JW, Van Andel AE, Wu C, Padula SJ, Fikrig E.
Department of Entomology, Connecticut Agricultural Experiment Station, New Haven 06504, USA.
OBJECTIVE: To determine whether horses living in tick-infested areas of northeastern United States with clinical signs of borreliosis or granulocytic ehrlichiosis had detectable serum antibodies to both Borrelia burgdorferi and Ehrlichia equi. DESIGN: Prospective study. ANIMALS: Serum samples from 51 clinically normal horses, 14 horses with clinical signs of borreliosis, and 17 horses with clinical signs of granulocytic ehrlichiosis. PROCEDURE: Serum B burgdorferi or E equi antibodies were measured by use of an ELISA, immunoblot analysis, or indirect fluorescent antibody (IFA) staining. RESULTS: Of the 82 serum samples tested, 37 (45.1% ) and 13 (15.9% ) had detectable antibodies to B burgdorferi or E equi, respectively. Test results indicated that 12 horses had been exposed to both agents, 11 of these horses had granulocytic ehrlichiosis. The ELISA regularly detected antibodies to the following recombinant protein (p) antigens of B burgdorferi: p29, p37, p39, and p41-G. The use of immunoblot analysis confirmed ELISA results by indicating antibody reactivities to antigens of whole-cell B burgdorferi having molecular masses of predominantly 31, 34, 37, 39, 41, 58, and 93 kd. CONCLUSIONS AND CLINICAL RELEVANCE: Horses living in areas where ticks (Ixodes scapularis) abound are sometimes exposed to multiple pathogens. Analyses for specific recombinant borrelial antibodies using an ELISA can help separate horses with borreliosis from those with granulocytic ehrlichiosis, even when antibodies to both etiologic agents are detected in serum samples. Analysis using immunoblots is sensitive, and along with ELISA or IFA procedures, is suitable for confirming a clinical diagnosis of each disease.
Vet Pathol. 2000 Jan;37(1):68-76.
Experimental infection of ponies with Borrelia burgdorferi by exposure to Ixodid ticks.
Chang YF, Novosol V, McDonough SP, Chang CF, Jacobson RH, Divers T, Quimby FW, Shin S, Lein DH.
Department of Population Medicine and Diagnostic Science, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
yc42@cornell.edu
Seven specific-pathogen-free (SPF) ponies, 1-5 years old, were exposed to Borrelia burgdorferi-infected adult ticks while being treated with dexamethasone over 5 consecutive days. One SPF pony (pony No. 17 was first exposed to laboratory-reared nymphs without B. burgdorferi infection and 3 weeks later was exposed to B. burgdorferi-infected adult ticks with concurrent dexamethasone treatment for 5 consecutive days. Four uninfected ponies treated with dexamethasone, exposed to laboratory-reared ticks without B. burgdorferi infection served as uninfected controls. Clinical signs, bacteriologic culture, polymerase chain reaction (PCR) for bacterial DNA, immunologic responses, and gross lesions and histopathologic changes were investigated during the experiment or at necropsy 9 months after tick exposure. In all of the seven challenged ponies, infection with B. burgdorferi was detected from monthly skin biopsies and various tissues at postmortem examination by culture and by PCR. However, pony No. 178 exposed to laboratory-reared nymphs (without B. burgdorferi infection) and challenged with B. burgdorferi-infected adult ticks 2 months later did not develop a B. burgdorferi infection. All of the infected ponies seroconverted. Control ponies and pony No. 178 were negative by culture, PCR, and serology. Except for skin lesions, we failed to induce any significant histopathologic changes in this study. This is the first report of successful tick-induced experimental infection in ponies by exposure to B. burgdorferi-infected ticks. This Lyme disease model will be very useful to evaluate efficacy of vaccines against the Lyme agent and the effect of antibiotic therapy on horses infected with B. burgdorferi.
Clin Diagn Lab Immunol. 2000 Jan;7(1):68-71.
Human granulocytic ehrlichiosis agent infection in a pony vaccinated with a Borrelia burgdorferi recombinant OspA vaccine and challenged by exposure to naturally infected ticks.
Chang YF, McDonough SP, Chang CF, Shin KS, Yen W, Divers T.
Department of Population Medicine and Diagnostic Science, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.
yc42@cornell.edu
A pony was vaccinated with recombinant OspA vaccine (rOspA) and then exposed 3 months later to Borrelia burgdorferi-infected ticks (Ixodes scapularis) collected in Westchester County, N.Y. At 2 weeks after tick exposure, the pony developed a high fever (105 degrees F). Buffy coat smears showed that 20% of neutrophils contained ehrlichial inclusion bodies (morulae). Flunixin Meglumine (1 g daily) was given for 2 days, and the body temperature returned to normal. PCR for ehrlichial DNA was performed on blood samples for 10 consecutive days beginning when the pony was first febrile. This pony was monitored for another 3.5 months but developed no further clinical signs. The 44-kDa immunodominant human granulocytic ehrlichiosis antigen gene was amplified by PCR and cloned into a pCR2.1 vector. DNA sequence analysis of this gene showed it was only 8 bp different (99% identity) from the results reported by others (J. W. Ijdo et al., Infect. Immun. 66:3264-3269, 199. Western blot analysis, growth inhibition assays, and repeated attempts to isolate B. burgdorferi all demonstrated the pony was protected against B. burgdorferi infection. These results highlight the potential for ticks to harbor and transmit several pathogens simultaneously, which further complicates the diagnosis and vaccination of these emerging tick-borne diseases.
J Vet Diagn Invest. 1998 Apr;10(2):196-9. Related Articles, Links
Viable Borrelia burgdorferi in the urine of two clinically normal horses.
Manion TB, Khan MI, Dinger J, Bushmich SL.
Department of Pathobiology, University of Connecticut, Storrs 06269, USA.
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