Real-time quantitative PCR.

The genera Anaplasma, Ehrlichia, Cowdria, Neorickettsia and Wolbachia encompass a group of obligate intracellular bacteria that reside in vacuoles of eukaryotic cells and were previously placed in taxa based upon morphological, ecological, epidemiological and clinical characteristics. Recent genetic analyses of 16S rRNA genes, groESL and surface protein genes have indicated that the existing taxa designations are flawed. All 16S rRNA gene and groESL sequences deposited in GenBank prior to 2000 and selected sequences deposited thereafter were aligned and phylogenetic trees and bootstrap values were calculated using the neighbour-joining method and compared with trees generated with maximum-probability, maximum-likelihood, majority-rule consensus and parsimony methods. Supported by bootstrap probabilities of at least 54%, 16S rRNA gene comparisons consistently clustered to yield four distinct clades characterized roughly as Anaplasma (including the Ehrlichia phagocytophila group, Ehrlichia platys and Ehrlichia bovis) with a minimum of 96.1% similarity, Ehrlichia (including Cowdria ruminantium) with a minimum of 97.7% similarity, Wolbachia with a minimum of 95.6% similarity and Neorickettsia (including Ehrlichia sennetsu and Ehrlichia risticii) with a minimum of 94.9% similarity. Maximum similarity between clades ranged from 87.1 to 94.9%. Insufficient differences existed among E. phagocytophila, Ehrlichia equi and the human granulocytic ehrlichiosis (HGE) agent to support separate species designations, and this group was at least 98.2% similar to any Anaplasma species. These 16S rRNA gene analyses are strongly supported by similar groESL clades, as well as biological and antigenic characteristics. It is proposed that all members of the tribes Ehrlichieae and Wolbachieae be transferred to the family Anaplasmataceae and that the tribe structure of the family Rickettsiaceae be eliminated. The genus Anaplasma should be emended to include Anaplasma (Ehrlichia) phagocytophila comb. nov. (which also encompasses the former E. equi and the HGE agent), Anaplasma (Ehrlichia) bovis comb. nov. and Anaplasma (Ehrlichia) platys comb. nov., the genus Ehrlichia should be emended to include Ehrlichia (Cowdria) ruminantium comb. nov. and the genus Neorickettsia should be emended to include Neorickettsia (Ehrlichia) risticii comb. nov. and Neorickettsia (Ehrlichia) sennetsu comb. nov.

/pdf/reorganization-of-genera-in-the-families-rickettsiaceae-and-2534zbx12v.pdf

Reorganization of genera in the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales: unification of some species of Ehrlichia with Anaplasma, Cowdria with Ehrlichia and Ehrlichia with Neorickettsia, descriptions of six new species combinations and designation of Ehrlichia equi and 'HGE agent' as subjective synonyms of Ehrlichia phagocytophila.

Evidence-based guidelines for the management of patients with Lyme disease, human granulocytic anaplasmosis (formerly known as human granulocytic ehrlichiosis), and babesiosis were prepared by an expert panel of the Infectious Diseases Society of America. These updated guidelines replace the previous treatment guidelines published in 2000 (Clin Infect Dis 2000; 31[Suppl 1]:1-14). The guidelines are intended for use by health care providers who care for patients who either have these infections or may be at risk for them. For each of these Ixodes tickborne infections, information is provided about prevention, epidemiology, clinical manifestations, diagnosis, and treatment. Tables list the doses and durations of antimicrobial therapy recommended for treatment and prevention of Lyme disease and provide a partial list of therapies to be avoided. A definition of post-Lyme disease syndrome is proposed.

/pdf/the-clinical-assessment-treatment-and-prevention-of-lyme-xajvcef2ye.pdf

The Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America

Ticks are currently considered to be second only to mosquitoes as vectors of human infectious diseases in the world. Each tick species has preferred environmental conditions and biotopes that determine the geographic distribution of the ticks and, consequently, the risk areas for tickborne diseases. This is particularly the case when ticks are vectors and reservoirs of the pathogens. Since the identification of Borrelia burgdorferi as the agent of Lyme disease in 1982, 15 ixodid-borne bacterial pathogens have been described throughout the world, including 8 rickettsiae, 3 ehrlichiae, and 4 species of the Borrelia burgdorferi complex. This article reviews and illustrate various aspects of the biology of ticks and the tickborne bacterial diseases (rickettsioses, ehrlichioses, Lyme disease, relapsing fever borrelioses, tularemia, Q fever), particularly those regarded as emerging diseases. Methods are described for the detection and isolation of bacteria from ticks and advice is given on how tick bites may be prevented and how clinicians should deal with patients who have been bitten by ticks.

/pdf/ticks-and-tickborne-bacterial-diseases-in-humans-an-emerging-2zzolyaitq.pdf

Ticks and tickborne bacterial diseases in humans: an emerging infectious threat

During most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. An element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. In this context, it was considered that relatively few tick-borne rickettsiae caused human disease. This concept was modified extensively from 1984 through 2005 by the identification of at least 11 additional rickettsial species or subspecies that cause tick-borne rickettsioses around the world. Of these agents, seven were initially isolated from ticks, often years or decades before a definitive association with human disease was established. We present here the tick-borne rickettsioses described through 2005 and focus on the epidemiological circumstances that have played a role in the emergence of the newly recognized diseases.

Tick-Borne Rickettsioses around the World: Emerging Diseases Challenging Old Concepts

Objective—To determine clinical, laboratory analysis, and necropsy findings for equids with oleander toxicosis and to identify factors associated with outcome. Design—Retrospective case series. Animals—30 equids. Procedures—Medical records of equids with detectable concentrations of oleandrin in serum, plasma, urine, or gastrointestinal fluid samples and equids that had not received cardiac glycoside drugs but had detectable concentrations of digoxin in serum were identified via a medical records database search. Descriptive statistics were calculated for medical history, physical examination, laboratory analysis, and necropsy variables. Logistic regression analysis was used to identify physical examination and laboratory analysis factors significantly associated with outcome. Results—3 of 30 (10.0%) equids died before or immediately after arrival at the hospital. Of the other 27 equids, 23 (85.2%) had gastrointestinal tract abnormalities, azotemia was detected for 19 (70.4%), and a cardiac arrhythmia was...

Oleander toxicosis in equids: 30 cases (1995-2010)

The most important clinical signs of BSE are hypersensitivity to manipulations of the head and neck and disturbances in behaviour and locomotion. Diagnostic procedures include thorough clinical and neurological examination with emphasis on the assessment of behaviour, locomotion and sensitivity. The findings have to be interpreted carefully and depending on the diagnosis, national animal health regulations must be followed.

Clinical examination upon suspicion of bovine spongiform encephalopathy (BSE)

The purpose of this study was to examine the seasonal variations in seroprevalence to Ehrlichia phagocytophila in cattle pastured during the summer months in an area where tick-borne fever is endemic. The study was performed during a 1-year period from April 1996 to March 1997 and involved 34 cows, 22 pregnant heifers, and 14 calves. Blood samples, collected from all 70 cattle once a month, were used to determine serum immunoglobulin G titers by indirect immunofluorescence. In addition, blood smears were examined for Ehrlichia organisms, and PCR amplification was performed for the molecular detection of E. phagocytophila. Prior to the pasture period, the seroprevalence was 16%. Two weeks after the start of pasturing, it was 43%, after which it progressively increased and reached a maximum of 63% in September. The seroprevalence progressively decreased after the end of pasturing to a low of 23%. The variation in antibody titers was similar to that of seroprevalence. E. phagocytophila organisms were detected in blood smears of 7 animals and by nested PCR in 12. Only four cows, which were on the pastures of endemicity for the first time, had clinical signs of ehrlichiosis. This study demonstrated marked seasonal variations in seroprevalence and in serum titers of antibody to E. phagocytophila in cattle. The incidence of clinical signs of ehrlichiosis was increased in cattle grazing on the pastures of endemicity for the first time.

https://www.zora.uzh.ch/id/eprint/167361/1/325.full.pdf

Serological, Hematologic, and PCR Studies of Cattle in an Area of Switzerland in Which Tick-Borne Fever (Caused by Ehrlichia phagocytophila) Is Endemic

A two-year-old female alpaca with multicentric lymphosarcoma presented because of progressive weakness and recumbency. The diagnosis of lymphosarcoma was based on the detection of immature and atypical lymphocytes in a lumbosacral CSF sample. Post mortem examination confirmed multicentric lymphosarcoma involving multiple organs. Immunophenotyping using cross reactive T- and B-cell antibodies characterized the tumour as a T-cell lymphosarcoma.

Multicentric T-cell lymphosarcoma in an alpaca

THE increasing application of sensitive molecular diagnostic techniques for the detection of pathogens in practice settings has presented new dilemmas with regard to how test results are interpreted and used by both equine practitioners and regulatory veterinarians. Because routine pcr assays

Nicola Pusterla

Papers

Oleander toxicosis in equids: 30 cases (1995-2010)

Clinical examination upon suspicion of bovine spongiform encephalopathy (BSE)

Serological, Hematologic, and PCR Studies of Cattle in an Area of Switzerland in Which Tick-Borne Fever (Caused by Ehrlichia phagocytophila) Is Endemic

Multicentric T-cell lymphosarcoma in an alpaca

Use of viral loads in blood and nasopharyngeal secretions for the diagnosis of EHV-1 infection in field cases.