Table 1

Tick-borne spotted fever group rickettsial agents of human diseases

Rickettsia species or strainRecognized or potential tick vector(s)Comment(s) (including related disease[s])Geographical distributiona
Rickettsia aeschlimannii Amblyomma variegatum, Rhipicephalus annulatus, Rhipicephalus evertsi evertsi, Rhipicephalus appendiculatus, Hyalomma marginatum rufipes, Hyalomma truncatum Spotted feverSub-Saharan Africa
Hyalomma marginatum marginatum, Hyalomma anatolicum excavatum, Ixodes ricinus, Rhipicephalus sanguineus, Rhipicephalus turanicus, Rhipicephalus bursa Spotted feverEurope
Haemaphysalis punctata, Hyalomma marginatum, Hyalomma detritum No human cases; identified in ticks in Kazakhstan and IsraelAsia
Hyalomma detritum detritum, Hyalomma marginatum marginatum, Hyalomma aegyptium, Hyalomma marginatum rufipes, Hyalomma dromedari, Hyalomma truncatum Detected in humans in Tunisia and Algeria and in ticks in Algeria, Morocco, Tunisia, and EgyptNorth Africa
Rickettsia africae Amblyomma variegatum, Amblyomma hebraeum, Amblyomma compressum, A. lepidum, Rhipicephalus annulatus, Rhipicephalus evertsi, Rhipicephalus decoloratus, Rhipicephalus sanguineus, Rhipicephalus geigyi, Hyalomma impeltatum African tick bite feverSub-Saharan Africa
Amblyomma variegatum Imported from Africa to the West Indies during the early 1800s; currently established in Guadeloupe, St. Kitts, Nevis, Dominica, U.S. Virgin Islands, Montserrat, St. Lucia, Martinique, and Antigua; causes eschar-associated illness, with clinical cases reported from GuadeloupeNorth and Central America
Amblyomma loculosum African tick bite feverPacific Islands
Hyalomma aegyptium No human cases reported from Asia; identified in ticks in TurkeyAsia
Hyalomma dromedarii No human cases; detected in dromedary ticks in sub-Saharan Algeria and EgyptNorth Africa
Rickettsia australis Ixodes holocyclus, Ixodes tasmani, Ixodes cornuatus Queensland tick typhusAustralia
Rickettsia sp. strain Atlantic rainforest or Bahia Amblyomma ovale, Amblyomma aureolatum, Rhipicephalus sanguineus Genetically related to R. parkeri, R. africae, and R. sibirica; 2 nonfatal cases reported in Brazil; symptoms include rash, eschar, and lymphadenopathySouth America
Rickettsia conorii subsp. caspia Rhipicephalus pumilio, Rhipicephalus sanguineus Astrakhan feverEurope
Rhipicephalus sanguineus, Rhipicephalus pumilio Astrakhan feverSub-Saharan Africa
Rickettsia conorii subsp. conorii Rhipicephalus sanguineus Mediterranean spotted feverEurope
Rhipicephalus sanguineus Mediterranean spotted fever human cases reported and detected in brown ticks in all North Africa areasNorth Africa
Rhipicephalus sanguineus, Rhipicephalus evertsi evertsi, Rhipicephalus simus, Rhipicephalus mushamae, Haemaphysalis punctaleachi, Haemaphysalis leachi Mediterranean spotted feverSub-Saharan Africa
Rhipicephalus sanguineus, Rhipicephalus bursa Asiatic part of TurkeyAsia
Rickettsia conorii subsp. indica Rhipicephalus sanguineus Indian tick typhusEurope, Asia
R. conorii subsp. israelensis Rhipicephalus sanguineus Israeli tick typhusEurope, Asia
Rhipicephalus sanguineus Israeli tick bite fever; 2 cases of ISF from Sfax confirmed by detection of rickettsia in skin biopsy specimensNorth Africa
Rickettsia heilongjiangensis Haemaphysalis concinna, Haemaphysalis japonica douglasi, Haemaphysalis flava, Dermacentor silvarum Far-Eastern spotted fever in Russia, China, South Korea, JapanAsia
Rickettsia helvetica Ixodes persulcatus Serologically confirmed cases only in Laos and Thailand; in Ixodes ticks in Japan and TurkeyAsia
Ixodes ricinus Europe
Ixodes ricinus No human cases; detected in Ixodes spp. in Algeria and MoroccoNorth Africa
Rickettsia honei Bothriocroton hydrosauri Flinders Island spotted feverAsia, Australia, and Pacific
Ixodes sp.Spotted fever identical to Flinders Island spotted fever in AustraliaAsia
Rickettsia honei strain marmionii Haemaphysalis novaeguineae Australian spotted feverAustralia
Rickettsia japonica Haemaphysalis flava, Haemaphysalis hystricis, Haemaphysalis longicornis, Haemaphysalis cornigera, Haemaphysalis formosensis, I. ovatus, D. taiwanensis Japanese spotted fever in Japan and South KoreaAsia
Candidatus Rickettsia kellyi”UnknownA single case reported from India; several amplicons from patients are referenced in GenBankAsia
Rickettsia massiliae Rhipicephalus sanguineus Recognized pathogen in other countries and detected in brown dog ticks in Arizona and California; no confirmed human cases in the U.S.North and Central America
Rhipicephalus sanguineus 1 case reported in a patient in Spain, recently arrived from Argentina; also reported to infect R. sanguineus in ArgentinaSouth America
Rhipicephalus turanicus, Rhipicephalus sanguineus, Rhipicephalus bursa, Rhipicephalus pusillus, Ixodes ricinus Spotted feverEurope
Rhipicephalus evertsi, Haemaphysalis paraleachi, Rhipicephalus senegalensis, Rhipicephalus guilhoni, Rhipicephalus lunulatus, Rhipicephalus sulcatus, Rhipicephalus muhsamae Spotted feverSub-Saharan Africa
Rhipicephalus turanicus, Rhipicephalus sanguineus Identified in ticks in IsraelAsia
Rhipicephalus sanguineus, Rhipicephalus turanicus No human cases; detected in Rhipicephalus spp. in Morocco, Algeria, and TunisiaNorth Africa
R. monacensis Ixodes ricinus Spotted fever (first clinical description 2007)Europe
Ixodes persulcatus Found only in ticks in Turkey
Ixodes ricinus No human cases; identified in Ixodes spp. in Tunisia, Algeria, and MoroccoNorth Africa
Rickettsia parkeri Amblyomma maculatum, Amblyomma americanum, Dermacentor variabilis Southeastern U.S.; causes mild, eschar-associated rickettsiosis; despite the occurrence of A. maculatum in Central America, no confirmed cases have been reported from that regionNorth and Central America
Amblyomma triste, Amblyomma tigrinum Causes spotted fever in Uruguay and Argentina; symptoms include rash, eschar, and lymphadenopathy; no fatal cases reported; also reported to infect ticks in Brazil and BoliviaSouth America
Rickettsia philipii (364D) Dermacentor occidentalis California; causes a relatively mild, eschar-associated illness; only a few recognized casesNorth and Central America
Rickettsia raoultii Dermacentor marginatus, Dermacentor reticulatus, Ixodes ricinus SENLAT (old TIBOLA/DEBONEL)Europe
Dermacentor silvarum, Dermacentor reticulatus, Dermacentor marginatus, Dermacentor nuttalli, Dermacentor niveus, Haemaphysalis ornithophila, Haemaphysalis shimoga, Haemaphysalis lagrangei, Amblyomma testudinarium No human cases; identified in Dermacentor species ticks in North Asia and in Haemaphysalis and Amblyomma ticks in South AsiaAsia
Dermacentor marginatus No human cases; identified in Dermacentor spp. in MoroccoNorth Africa
Rickettsia rickettsii Dermacentor andersoni, Dermacentor variabilis, Dermacentor occidentalis, Dermacentor nitens, Rhipicephalus sanguineus, Amblyomma cajennense, Amblyomma americanum Amblyomma imitator, Haemaphysalis leporispalustris Causes Rocky Mountain spotted fever, the most severe rickettsiosis in the world; occurs sporadically and infrequently in ticks throughout Canada, the U.S., Mexico, Costa Rica, and PanamaNorth and Central America
Amblyomma cajennense, Amblyomma aureolatum, Rhipicephalus sanguineus Causes the most severe spotted fever, namely, Rocky Mountain spotted fever or Brazilian spotted fever; reported in Argentina, Brazil, and Colombia; current case fatality rate of 20–40%South America
Rickettsia sibirica subsp. mongolitimonae Hyalomma anatolicum excavatum, Rhipicephalus pusillus LAREurope
Hyalomma truncatum LARSub-Saharan Africa
Hyalomma asiaticum Type strain isolated in China; no cases from Asia have been reported; identified in IsraelAsia
Hyalomma sp.1 human caseNorth Africa
Rickettsia sibirica subsp. sibirica Dermacentor nuttalli, Dermacentor marginatus, Dermacentor reticulatus, Dermacentor silvarum, Dermacentor sinicus, Haemaphysalis yeni, Haemaphysalis concinna, Ixodes persulcatus Siberian tick typhus in Russia, China, and MongoliaAsia
Rickettsia slovaca Dermacentor marginatus, Dermacentor reticulatus SENLAT (TIBOLA/DEBONEL)Europe
Dermacentor ticksNo human cases in Asia; identified in Russia and ChinaAsia
Dermacentor marginatus SENELAT (TIBOLA DEBONEL); no human cases; detected in Dermacentor ticks from Algeria and MoroccoNorth Africa
Rickettsia tamurae Amblyomma testudinarium Case was reported from Japan and LaosAsia
  • a See figures.