See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/312263467 Guidelines for the Direct Detection of Anaplasma spp. in Diagnosis and Epidemiological Studies Article in Vector Borne and Zoonotic Diseases · January 2017 DOI: 10.1089/vbz.2016.1960 CITATIONS READS 6 369 13 authors, including: Cornelia Silaghi Ana Sofia Santos Friedrich Loeffler Institute National Institute of Health Dr. Ricardo Jorge 250 PUBLICATIONS 2,287 CITATIONS 72 PUBLICATIONS 575 CITATIONS SEE PROFILE SEE PROFILE Jacinto Gomes Iva Christova Instituto Nacional de Investigação Agrária e Veterinária (INIAV) National Centre of Infectious and Parasitic Diseases, Bulgaria 65 PUBLICATIONS 253 CITATIONS 104 PUBLICATIONS 1,105 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Pathogenesis and control of Flaviviruses: Cocirculation and Co-infection of resident and migratory avian hosts throughout Spain View project REVIVE Network - Entomological surveillance in Portugal View project All content following this page was uploaded by Ana Domingos on 27 November 2017. The user has requested enhancement of the downloaded file. VECTOR-BORNE AND ZOONOTIC DISEASES Volume 17, Number 1, 2017 ª Mary Ann Liebert, Inc. DOI: 10.1089/vbz.2016.1960 Guidelines for the Direct Detection of Anaplasma spp. in Diagnosis and Epidemiological Studies Cornelia Silaghi,1,* Ana Sofia Santos,2,* Jacinto Gomes,3 Iva Christova,4 Ioana Adriana Matei,5 Gernot Walder,6 Ana Domingos,7 Lesley Bell-Sakyi,8 Hein Sprong,9 Friederike D. von Loewenich,10 Jose´ A. Oteo,11 Jose´ de la Fuente,12,13 and J. Stephen Dumler14,15 Abstract The genus Anaplasma (Rickettsiales: Anaplasmataceae) comprises obligate intracellular Gram-negative bacteria that are mainly transmitted by ticks, and currently includes six species: Anaplasma bovis, Anaplasma centrale, Anaplasma marginale, Anaplasma phagocytophilum, Anaplasma platys, and Anaplasma ovis. These have long been known as etiological agents of veterinary diseases that affect domestic and wild animals worldwide. A zoonotic role has been recognized for A. phagocytophilum, but other species can also be pathogenic for humans. Anaplasma infections are usually challenging to diagnose, clinically presenting with nonspecific symptoms that vary greatly depending on the agent involved, the affected host, and other factors such as immune status and coinfections. The substantial economic impact associated with livestock infection and the growing number of human cases along with the risk of transfusion-transmitted infections, determines the need for accurate laboratory tests. Because hosts are usually seronegative in the initial phase of infection and serological cross-reactions with several Anaplasma species are observed after seroconversion, direct tests are the best approach for both case definition and epidemiological studies. Blood samples are routinely used for Anaplasma spp. screening, but in persistently infected animals with intermittent or low-level bacteremia, other tissues might be useful. These guidelines have been developed as a direct outcome of the COST action TD1303 EURNEGVEC (‘‘European Network of Neglected Vectors and Vector-Borne Diseases’’). They review the direct laboratory tests (microscopy, nucleic acid-based detection and in vitro isolation) currently used for Anaplasma detection in ticks and vertebrates and their application. Keywords: Anaplasma spp., direct diagnosis, in vitro isolation, microscopy, PCR, ticks, vertebrate hosts 1National Center for Vector Entomology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland. 2Center for Vector and Infectious Diseases Research, National Institute of Health Doutor Ricardo Jorge, A´ guas de Moura, Portugal. 3Animal Health and Production Unit, National Institute for Agrarian and Veterinary Research, Oeiras, Portugal. 4Department of Microbiology, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria. 5Department of Parasitology and Parasitic Diseases, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania. 6Department of Hygiene, Medical Microbiology and Social Medicine, Innsbruck Medical University, Innsbruck, Austria. 7Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal. 8The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, United Kingdom. 9Center for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands. 10Department of Medical Microbiology and Hygiene, University of Mainz, Medical Center, Mainz, Germany. 11Infectious Diseases Department, Center of Rickettsioses and Arthropod-Borne Diseases, Hospital San Pedro- CIBIR, Logron˜o, Spain. 12SaBio. Instituto de Investigacio´n de Recursos Cinege´ticos, IREC-CSIC-UCLM-JCCM, Ciudad Real, Spain. 13Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma. 14Departments of Pathology and Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland. 15Department of Pathology, Uniformed Services University for the Health Sciences ‘‘America’s Medical School,’’ Bethesda, Maryland. *These authors contributed equally to this work. 12 ANAPLASMA SPP. DIRECT DETECTION 13 Introduction Peripheral blood smears directly prepared after fingerstick or superficial vein puncture or from venous blood collected embers of the genus Anaplasma (Rickettsiales: into anticoagulant, obtained during the early acute phase of MAnaplasmataceae) are non-motile, obligate intracellu- symptoms and before initiation of effective antimicrobial lar Gram-negative bacteria residing in membrane-bound therapy, are best for visualization of bacteria in both animals cytoplasmic vacuoles of the host cell where they form ag- and humans. This time frame for sample collection is crucial glomerates called morulae (Latin morus = mulberry). Fol- for all direct tests, including molecular detection and in vitro lowing the reorganization of the order Rickettsiales in 2001, cultivation, as it covers the stage of infection when sufficient the genus Anaplasma contains at least six species: Anaplasma numbers of bacteria are present in the circulating blood. For bovis, Anaplasma centrale, Anaplasma marginale, Anaplas- leukocytotropic species (A. bovis and A. phagocytophilum), ma phagocytophilum, Anaplasma platys, and Anaplasma ovis buffy coat smears are preferred to regular whole blood pre- (Dumler et al. 2001, 2005). In future, recently identified parations, as due to leukopenia very few infected leukocytes agents such as Anaplasma odocoilei and Anaplasma capra may be present. Representing a leukocyte- and platelet- could be included (Tate el al. 2013, Li et al. 2015). Anaplasma enriched fraction, buffy coat is also considered useful for spp. are etiologic agents of veterinary diseases affecting detection of A. platys morulae within platelets (Eddlestone domestic ruminants, equines, dogs, and cats worldwide. et al. 2007). In any case, bacterial detection is best achieved if A. phagocytophilum is also regarded as an emerging human smears are prepared immediately after blood collection. Al- pathogen with growing importance in the Northern Hemi- ternatively, anticoagulated samples can be refrigerated and sphere (Jin et al. 2012, Bakken and Dumler 2015). Reports processed preferably within 24–48 h. At post-mortem exam- of human infections caused by other species such as A. platys, ination, tissue impressions or smears (spleen, liver, kidney, A. ovis, and the putative A. capra, suggest a broader medical heart, lung and, in particular, blood vessels) can be performed relevance of this taxon (Chochlakis et al. 2010, Maggi et al. in an attempt to visualize erythrocytotropic Anaplasma spp. 2013, Arraga-Alvarado et al. 2014, Breitschwerdt et al. 2014, (Kocan et al. 2010, OIE 2015). After being dried and fixed in Li et al. 2015). methanol, smears are stable for at least 2 months. Differential Anaplasma exhibit a biological cycle involving infection staining is achieved with Eosin Azure (Romanovsky)-type of both invertebrate and vertebrate hosts. Ticks are regarded dyes such as Giemsa and Diff-Quik; Anaplasma morulae as primary vectors, with different cell types targeted by these typically appear in the host cells as dark blue to purple for- agents in a replication cycle, including invasion of salivary mations by light microscopic examination at 400· or 1000· glands and transmission in saliva released during blood magnification. Open access reference images can be found in feeding. Alternative transmission routes include mechanical the literature of A. bovis (Liu et al. 2012), A. centrale (Bell- transfer by other hematophagous arthropods or fomites such Sakyi et al. 2015), A. marginale (Kocan et al. 2003), A. pha- as contaminated veterinary instruments, and transfusion- gocytophilum (Annen et al. 2012, Henniger et al. 2013), A. transmitted infections (Leiby and Gill 2004, Aubry and Geale platys (Dyachenko et al. 2012), and A. ovis (Yasini et al. 2012). 2011, Renneker et al. 2013, Shields et al. 2015). Anaplasma Light microscopy is the most inexpensive and quickest spp. display unique cell tropisms in vertebrate hosts and de- laboratory test, but also the least sensitive, and is highly pending on the species, different cells of the hematopoietic dependent on examiner experience, relative