Human Granulocytic Ehrlichiosis Agent Infection in a Pony Vaccinated with aBorrelia burgdorferiRecombinant OspA Vaccine and Challenged by Exposure to Naturally Infected Ticks

Abstract

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°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, 1998). 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.

Control of Lyme borreliosis and other Ixodes ricinus-borne diseases

“…A broad spectrum of clinical signs has been associated to Borrelia infections in animals, including fever, lethargy, weight loss, (shifting) lameness, ataxia, uveitis, polyarthritis, glomerulopathy and neuritis [ 96 – 98 ]. This variation might to some extent be the result of unapparent co-infections with other pathogens, such as A. phagocytophilum [ 99 , 100 ].…”

Anaplasma phagocytophilum infection in horses in the Netherlands

“…The disease has previously been referred to as equine granulocytic ehrlichiosis, and is transmitted in Europe by Ixodes ricinus ticks. Ticks of the I ricinus complex also act as vectors in the spread of Borrelia burgdorferi from one animal to another, and co‐infections of A phagocytophilum and B burgdorferi have been confirmed in horses (Chang and others 2000a, Magnarelli and others 2000).…”

La maladie de Lyme chez le cheval : un défi clinique et diagnostique

“…Il inclut les affections ostéo-articulaires, la myopathie de stockage en polysaccharides (PSSM), les autres myopathies et polysynovites chroniques. La fièvre et l'oedème des membres caractéristique du « syndrome piro-like » sont plus souvent le reflet d'une coinfection par Anaplasma phagocytophilum (Persing 1997, Chang 2000b, Engvall 2002 Il n'existe pas de consensus sur la molécule de choix. D'après l'ensemble de ces critères, les antibiotiques actuellement recommandés sont les suivants :…”