Journal article
Molecular detection of Rickettsia felis and Candidatus Rickettsia Asemboensis in Fleas from Human Habitats, Asembo, Kenya
Vector borne and zoonotic diseases (Larchmont, N.Y.), Vol.13(8), pp.55-558
08/01/2013
Handle:
https://hdl.handle.net/2376/104886
PMCID: PMC3741420
PMID: 23675818
Abstract
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 rickettsia-positive 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 agent-specific 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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Details
- Title
- Molecular detection of Rickettsia felis and Candidatus Rickettsia Asemboensis in Fleas from Human Habitats, Asembo, Kenya
- Creators
- Ju Jiang - 1Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MarylandAlice N Maina - 3Kenya Medical Research Institute, Kisumu, KenyaDarryn L Knobel - 4Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort, South AfricaSarah Cleaveland - 5College of Medicine, Veterinary Medicine and Life Sciences, University of Glasgow, Glasgow, United KingdomAnne Laudisoit - 10Evolutionary Ecology Group, University of Antwerp, Antwerpen, BelgiumKabura Wamburu - 7US Centers for Disease Control and Prevention, Nairobi, KenyaEric Ogola - 3Kenya Medical Research Institute, Kisumu, KenyaPhilippe Parola - 8WHO Collaborative Center for Rickettsial and Other Arthropod-borne Bacterial Infections, UMR 7278CNRS IRD, IFR 48, Aix Marseille University, Marseille, FranceRobert F Breiman - 7US Centers for Disease Control and Prevention, Nairobi, KenyaM. Kariuki Njenga - 7US Centers for Disease Control and Prevention, Nairobi, KenyaAllen L Richards - 9Uniformed Services University of the Health Sciences, Bethesda, Maryland
- Publication Details
- Vector borne and zoonotic diseases (Larchmont, N.Y.), Vol.13(8), pp.55-558
- Academic Unit
- Paul G. Allen School for Global Animal Health
- Publisher
- Mary Ann Liebert, Inc
- Identifiers
- 99900546788601842
- Language
- English
- Resource Type
- Journal article