ESCCAR (European Study group on Chlamydiales, Coxiella, Anaplasma, Rickettsia and other intracellular bacteria)

ESCCAR encourages basic and applied research in the field of chlamydiology, rickettsiology and related diseases due to intracellular bacteria. ESCCAR has currently about 271 members (medical doctors, veterinarians, microbiologists, ….) from many different countries. Bacterial diseases studied include chlamydiosis, rickettsiosis, bartonellosis, ehrlichosis, and coxiellosis as well as emerging infectious diseases due to novel intracellular bacteria (i.e. Chlamydia-related bacteria, Neoehrlichia, …).

ESCCAR is the organizer of the triennal International Meeting on Rickettsiae and Rickettsial diseases, as well as educational workshops (see below : “activities”), and is publishing special issues related to each triennial meetings, congress reports, as well as results of collaborative research and/or guidelines (see below: “publications”).

ESCCAR, formerly ESCAR (a study group) from the ESCMID, was created in Barcelona in May 2014 during the 24th ECCMID to continue its activity outside ESCMID and to now also include Chlamydia and Chlamydia-related bacteria.


  • 2008 : ESCCAR International Congress on Rickettsia and other Intracellular Bacteria, held in Marseille, France.
  • 2010 ESCCAR postgraduate course in Sousse, Tunisia organized by A Letaief.
  • 2011 : ESCCAR International Congress on Rickettsia and other Intracellular Bacteria, held in Heraklion, Creta, Greece.
  • 2013 : ESCMID Postgraduate course on Intracellular Bacteria, held in Villars-sur-Ollon, Switzerland.
  • 2014 ESCCAR postgraduate course in Marseille, France organized by PE Fournier.
  • 2015 : ESCCAR International Congress on Rickettsia and other Intracellular Bacteria, held in Lausanne, Switzerland
  • 2017 : ESCCAR International Congress on Rickettsia and other Intracellular Bacteria, held in Marseille, organized by P.E. Fournier from 19 to 21 June 2017
  • 2020 : International intracellular bacteria meeting 2020, organized by G. Greub in Lausanne, Switzerland. Due to the COVID-19, the congress is postponed to August 2021: from Tuesday 24 to Friday 27. Information and registration

Recent ESCCAR publications

  • ESCMID/ESGMD postgraduate technical workshop on diagnostic microbiology

    Aurélie Scherler, Silvia Ardissone, Jacob Moran-Gilad, Gilbert Greub
    Microbes infect. May 2019

  • ESCMID postgraduate technical workshop on intracellular bacteria: From biology to clinic.
    Pilloux L and Greub G
    Microbes Infect. 2014: S1286-4579(14)
    This article is highlighting the topics covered during the recent ESCAR meeting held in Villars (Switzerland).
  • Update on Tick-Borne Rickettsioses around the World: a Geographic Approach
    Parola P et al.
    Clin Microbiol Rev. 2013 Oct;26(4):657-702
    This article presents current knowledge on tick-borne rickettsiae and rickettsioses with maps providing detailed geographic information on the epidemiology of these diseases.
  • ESCCAR international congress on Rickettsia and other intracellular bacteria.
    de Barsy M, Bertelli C, Jacquier N, Kebbi-Beghdadi C, Greub G.
    Microbes Infect. 2015 Oct;17(10):680-8.
    This article summuarized the main discoveries presented at the International Congress held in Lausanne (Switzerland) in june 2015

Mission & Objectives

ESCCAR, formerly ESCAR & EUWOG, is the acronym for the European Study group on Chlamydiae, Coxiella, Anaplasma, Rickettsia and other intracellular bacteria.

What are the rationale and objectives of a our Study group ?

  • Chlamydiae includes the classical C. trachomatis, C. pneumoniae and C. psittacci pathogens, but also a large variety of new families, genera and species, including Waddlia chondrophila, an newly identified agent of miscarriage and Parachlamydia acanthamoebae, an emerging agent of pneumonia. Research on these novel Chlamydiae may provide significant insight on the biology of all members of the Chlamydiales order and is facing the same difficulties and challenges than that faced by the rickettsiologist community. Members of ESCCAR are mainly interested in the epidemiology of these novel Chlamydia-related bacteria since they were also identified present in ticks and represent emerging zoonotic agents.
  • Rickettsiosis and related diseases are not only classical infectious diseases that caused thousands of deaths in previous eras. Currently, rickettsioses are emerging and re-emerging infections that cause many health problems not only in poorer countries but also in developed nations. The recent epidemic of typhus in Burundi with thousands of affected people, exemplifies re-emerging rickettsiosis. In some areas other classical rickettsioses as Mediterranean Spotted Fever, or Rocky Mountain Spotted Fever are endemic. Other infections are being spread all over the world such as those caused by Rickettsia felis, closely tied to humans due to their transmission by the cat flea. In the last 10 years, thanks to the use of new molecular tools, for instance PCR, numerous species of the spotted fever group of Rickttsiae have been implicated as human pathogens. Using PCR the Marseille Group (Didier Raoult et al.) has described human infections by R. mongolotimonae, R. aeschelimani, or R. slovaca among others. An important Rickettsiosis, known as TIBOLA or DEBONEL, is distributed all around Europe and is a frequent cause of scar and lymphadenopathy in people bitten by ticks in cool months. Another emerging health problem is infection caused by R. africae. This illness affects a large number of travellers to South Africa and other southern African countries.
  • We also study infections caused by Ehrlichia sp. and Anaplasma sp. (ehrlichiosis), which have been recognised pathogens in mammals since the beginning of the 20th century in Europe. After the first European descriptions in humans, human granulocytic ehrlichiosis or human anaplasmosis was described Europe-wide, and we know that a large percentage of Ixodes ricinus ticks is infected by the etiologic agent Anaplasma phagocytophilum. Recently, a new species found in northern Italy has been described that could be a human pathogen (E. walkerii).
  • Bartonella infections are currently a significant problem worldwide. It has been demonstrated that B. quintana is the cause of new cases of “Trench Fever” now called “Urban Trench Fever” because it affects urban homeless populations. This is an example of a re-emerging infection. We also know that B. henselae is one of the main etiologic agents of lymphadenopathy in children and young people and that Bartonella sp. are the main pathogens of culture-negative endocarditis. Sadly enough Rickettsia sp. and Coxiella burnetti are also “fashionable” bio-terrorism threats. Although these agents are not easy to employ as biological weapons, they are still classified as Class B agents.
  • Obviously, almost all pathogens that we study in ESCCAR also cause disease in other mammals, and they are of interest not only to physicians and microbiologists but also to veterinarians and other specialists.
  • The aim of ESCCAR is to encourage basic and applied research in the field of chlamydiology, rickettsiology and related diseases. ESCCAR has approximately 300 members (medical doctors, microbiologists, scientists, veterinarians, pharmacists, etc.) from most European countries and many other countries around the world, including the USA, Japan, and Russia. Our main research fields are: epidemiology, genomics, taxonomy, diagnosis, physiopathology, immunology and therapy of chlamydiosis, rickettsiosis, bartonellosis, anaplasmosis, and coxiellosis in humans and animals.
  • We make recommendations on research issues related to rickettsiae and rickettsial diseases in order to advance basic understanding and knowledge in this field. ESCCAR also advises government health agencies, if necessary, on important aspects of these diseases
 Last updated on 17/11/2023 at 10:38