Human Infection with<i>Rickettsia felis,</i>Kenya

Richards, Allen L.; Jiang, Ju; Omulo, Sylvia; Dare, Ryan K; Abdirahman, Khalif; Ali, Abdile; Sharif, Shahnaaz; Feikin, Daniel R.; Breiman, Robert F.; Njenga, M. Kariuki

doi:10.3201/eid1607.091885

Cited by 108 publications

(101 citation statements)

References 35 publications

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“…However, in the same area of Asembo where 50 of 699 (7.2%) fever patients were determined to have FBSF, 21 of 21 molecular isolates from the 50 positive blood samples had sequence-confirmed R. felis DNA (Maina et al 2012). Similarly, in a study of non-malaria fever patients, 6 of 163 (3.7%) patients had evidence of FBSF, and all 6 samples were sequence verified to have R. felis DNA in the serum samples (Richards et al 2010). Candidatus R. asemboensis was not detected in any patients' samples from those areas.…”

Section: Discussionmentioning

confidence: 99%

“…Early on, R. felis was determined to be a human pathogen (Shriefer et al 1994) causing flea-borne spotted fever (FBSF) that now is frequently diagnosed around the world, especially in subSaharan Africa (Parola 2011). Two recent reports from our group have shown FBSF due to infection with R. felis to be endemic to both the northeastern and western regions of Kenya (Richards et al 2010, Maina et al 2012. Risk factors of flea-borne rickettsioses in humans have not been fully characterized in those areas.…”

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confidence: 88%

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Molecular detection ofRickettsia felis and CandidatusRickettsia Asemboensis in Fleas from Human Habitats, Asembo, Kenya

Jiang

Maina

Knobel

et al. 2013

Vector-Borne and Zoonotic Diseases

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108

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The flea-borne rickettsioses murine typhus (Rickettsia typhi) and flea-borne spotted fever (FBSF) (Rickettsia felis) are febrile diseases distributed among humans worldwide. Murine typhus has been known to be endemic to Kenya since the 1950s, but FBSF was only recently documented in northeastern (2010) and western (2012) Kenya. To characterize the potential exposure of humans in Kenya to flea-borne rickettsioses, a total of 330 fleas (134 pools) including 5 species (Xenopsylla cheopis, Ctenocephalides felis, Ctenocephalides canis, Pulex irritans, and Echidnophaga gallinacea) were collected from domestic and peridomestic animals and from human dwellings within Asembo, western Kenya. DNA was extracted from the 134 pooled flea samples and 89 (66.4%) pools tested positively for rickettsial DNA by 2 genus-specific quantitative real-time PCR (qPCR) assays based upon the citrate synthase (gltA) and 17-kD antigen genes and the Rfelis qPCR assay. Sequences from the 17-kD antigen gene, the outer membrane protein (omp)B, and 2 R. felis plasmid genes (pRF and pRFd) of 12 selected rickettsiapositive samples revealed a unique Rickettsia sp. (n = 11) and R. felis (n = 1). Depiction of the new rickettsia by multilocus sequence typing (MLST) targeting the 16S rRNA (rrs), 17-kD antigen gene, gltA, ompA, ompB, and surface cell antigen 4 (sca4), shows that it is most closely related to R. felis but genetically dissimilar enough to be considered a separate species provisionally named Candidatus Rickettsia asemboensis. Subsequently, 81 of the 134 (60.4%) flea pools tested positively for Candidatus Rickettsia asemboensis by a newly developed agentspecific qPCR assay, Rasemb. R. felis was identified in 9 of the 134 (6.7%) flea pools, and R. typhi the causative agent of murine typhus was not detected in any of 78 rickettsia-positive pools assessed using a species-specific qPCR assay, Rtyph. Two pools were found to contain both R. felis and Candidatus Rickettsia asemboensis DNA and 1 pool contained an agent, which is potentially new.

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Section: Discussionmentioning

confidence: 99%

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confidence: 88%

Molecular detection ofRickettsia felis and CandidatusRickettsia Asemboensis in Fleas from Human Habitats, Asembo, Kenya

Jiang

Maina

Knobel

et al. 2013

Vector-Borne and Zoonotic Diseases

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108

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“…These works identified a novel healthcare problem in Africa: acute R. felis-induced fever that mimics malaria. 3,6 Evidently, this acute fever may be responsible for a significant proportion of the non-malarial fevers in Africa. However, the epidemiology and clinical picture of this acute R. felis fever remain to be characterized.…”

Section: Discussionmentioning

confidence: 99%

“…3,4 Among febrile patients, the overall reported incidence of illness caused by R. felis was approximately 2-4%, and similar results have been independently reported for Kenya. 5,6 Moreover, tick-borne Rickettsia species (R. conorii, R. africae, R. massiliae, R. aeschlimannii, and R. sibirica mongolitimonae) were identified in vectors and patients in Senegal, where seroprevalence against spotted fever group rickettsiae in the healthy population may reach 51%. 7,8 A diagnosis of acute spotted fever group rickettsiosis is typically based on a combination of clinical (fever, rash, and presence of eschar), epidemiological (arthropod bite or contact), and laboratory data.…”

Section: Introductionmentioning

confidence: 99%

Molecular Identification of Pathogenic Bacteria in Eschars from Acute Febrile Patients, Senegal

Mediannikov

Socolovschi

Million

et al. 2014

The American Society of Tropical Medicine and Hygiene

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Abstract. Fever caused by Rickettsia felis was recently shown to play an important role in infectious diseases morbidity in sub-Saharan Africa. We collected 68 cotton swabs from fever-associated eschars in four different regions of Senegal. In 5 of 68 eschar samples (7.4%), we have identified DNA from R. felis. In 49 of 68 eschar samples (72.1%), we have identified DNA from Staphylococcus aureus. In 35 of 68 eschar samples (51.5%), we have identified DNA from Streptococcus pyogenes, and in 4 of 68 eschar samples (5.9%), we have identified DNA from Streptococcus pneumoniae. In 34 cases, S. aureus was found together with S. pyogenes. DNA from R. felis was also found in swabs from the skin of the healthy Senegalese villagers (3 of 60; 5%) but not French urbanites. The presence of S. aureus and S. pyogenes was significantly associated with the presence of eschars in febrile patients compared with the healthy skin from the control group. Finally, we confirmed that Senegal is an endemic region for R. felis, which is found in both eschars and healthy skin swabs.

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“…En Latinoamérica y el Caribe, actualmente se destaca como la especie reportada en el mayor número de países (9). Es evidente, entonces, que R. felis está emergiendo y es importante en la etiología del síndrome febril agudo (10)(11)(12).…”

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Caso probable de fiebre manchada (Rickettsia felis) transmitida por pulgas

et al. 2012

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33(Supl.1):9-13 Fiebre manchada transmitida por pulgas Contribución de los autores:Álvaro Adolfo Faccini se encargó de la revisión de la literatura científica y la redacción del manuscrito. Marylin Hidalgo asesoró la revisión, sugirió modificaciones de estilo, corrigió el manuscrito y suministró ideas para la discusión Elkin G. Forero, Jesús A. Cortés, Luis J. Polo, Jorge H. Jácome, Jimmy J. Vargas y Gustavo Valbuena, asesoraron la revisión y son coinvestigadores del proyecto del cual es producto este manuscrito. PRESENTACIÓN DE CASO Biomédica 2013;33(Supl. Rickettsia felis es el agente etiológico de la fiebre manchada transmitida por pulgas, cuyo principal vector y reservorio es Ctenocephalides felis. Típicamente, la enfermedad se presenta como fiebre aguda asociada a cefalea, astenia, exantema máculo-papular generalizado y, en algunos casos, con escara de inoculación. En los últimos años, R. felis ha venido adquiriendo un papel importante en la etiología del síndrome febril agudo, calificándola como una enfermedad emergente y subdiagnosticada. La inmunofluorescencia indirecta es actualmente el método diagnóstico de referencia. Sin embargo, esta técnica presenta limitaciones relacionadas con la reacción cruzada que existe entre las diferentes especies del género Rickettsia. En el presente reporte se describe el caso de un paciente de 16 años con síndrome febril agudo secundario a infección probable por R. felis. Probable case of flea-borne spotted fever (Rickettsia felis)Rickettsia felis is the etiologic agent of flea-borne spotted fever, with Ctenocephalides felis as its main vector and reservoir. Typically, the disease presents as acute fever associated with headache, asthenia, generalized maculo-papular rash, and in some cases, an inoculation eschar. In recent years, R. felis has acquired an important role in the etiology of the acute febrile syndrome; it is indeed an emerging infectious disease, albeit underdiagnosed. Indirect immunofluorescence assay (IFA) is currently the reference diagnostic method. However, this technique has limitations related to the cross reactivity among different species of rickettsiae. Herein, we describe a case of a 16 year-old patient with an acute febrile syndrome secondary to probable infection with R. felis. Key words:Case studies, Rickettsia felis, fever, Rickettsia infections, Colombia. doi: http://dx.doi.org/10. 7705/biomedica.v33i0.723 Las rickettsiosis son entidades clínicas causadas por bacterias intracelulares del género Rickettsia que afectan al hombre al ser transmitidas por artrópodos vectores (1). Los miembros de este género bacteriano se clasifican actualmente en cuatro grupos según sus características genéticas: grupo de las fiebres manchadas (R. rickettsii, R. conorii y R. parkeri, entre otras), grupo del tifus (R. prowazekii y R. typhi), grupo transicional (R. felis, R. akari y R. australis) y grupo ancestral (R. bellii y R. canadensis); este último no tiene un caracter patógeno conocido (1).Rickettsia felis es el agente etiológico de la fiebre manchada t...

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Human Infection withRickettsia felis,Kenya

Abstract: This flea-borne pathogen was detected in febrile patients in North Eastern Province, Kenya.

Cited by 108 publications

References 35 publications

Molecular detection ofRickettsia felis and CandidatusRickettsia Asemboensis in Fleas from Human Habitats, Asembo, Kenya

Molecular detection ofRickettsia felis and CandidatusRickettsia Asemboensis in Fleas from Human Habitats, Asembo, Kenya

Molecular Identification of Pathogenic Bacteria in Eschars from Acute Febrile Patients, Senegal

Caso probable de fiebre manchada (Rickettsia felis) transmitida por pulgas

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