Detection of Rickettsia asembonensis in Fleas (Siphonaptera: Pulicidae, Ceratophyllidae) Collected in Five Counties in Georgia, United States.

We conducted a molecular survey of Rickettsia in fleas collected from opossums, road-killed and live-trapped in peridomestic and rural settings, state parks, and from pet cats and dogs in Georgia, United States during 1992-2014. The cat flea, Ctenocephalides felis (Bouché) was the predominant species collected from cats and among the archival specimens from opossums found in peridomestic settings. Polygenis gwyni (Fox) was more prevalent on opossums and a single cotton rat trapped in sylvatic settings. Trapped animals were infested infrequently with the squirrel flea, Orchopeas howardi (Baker) and C. felis. TaqMan assays targeting the BioB gene of Rickettsia felis and the OmpB gene of Rickettsia typhi were used to test 291 flea DNAs for Rickettsia. A subset of 53 C. felis collected from a cat in 2011 was tested in 18 pools which were all bioB TaqMan positive (34% minimum infection prevalence). Of 238 fleas tested individually, 140 (58.8%, 95% confidence interval [CI]: 52.5-64.9%) DNAs were bioB positive. Detection of bioB was more prevalent in individual C. felis (91%) compared to P. gwyni (13.4%). Twenty-one (7.2%) were ompB TaqMan positive, including 18 C. felis (9.5%) and 3 P. gwyni (3.2%). Most of these fleas were also positive with bioB TaqMan; however, sequencing of gltA amplicons detected only DNA of Rickettsia asembonensis. Furthermore, only the R. asembonensis genotype was identified based on NlaIV restriction analysis of a larger ompB fragment. These findings contribute to understanding the diversity of Rickettsia associated with fleas in Georgia and emphasize the need for development of more specific molecular tools for detection and field research on rickettsial pathogens.

Molecular Survey for Pathogens and Markers of Permethrin Resistance in Human Head Lice (Phthiraptera: Pediculidae) from Madagascar.

Human infestation with head lice, Pediculus humanus capitis De Geer, is the most prevalent ectoparasitic condition in the modern world. The purpose of this study was to test human head lice from Madagascar for infection with 2 louse-borne bacteria, Bartonella quintana and Acinetobacter spp. including Acinetobacter baumannii, to assess the potential risk of exposure to these pathogens in rural populations experiencing head-louse pediculosis. A second aim was to determine the occurrence of a biomarker for permethrin resistance in head lice from 6 isolated human communities in Madagascar. Deoxyribonucleic acid (DNA) of B. quintana was detected using species-specific Fab3 gene TaqMan in 12.6% of lice from 4 villages. DNA of Acinetobacter spp. was detected using rpoB TaqMan in 42.1% of lice collected from all locations; 58.3% of rpoB-positive lice had the blaOXA51-like enzyme gene specific for A. baumannii. The kdr-resistant allele was detected in 70% of lice tested and was found in lice from each location. These results provide the first information regarding these combined characteristics of head-louse infestations in Madagascar. This approach can be applied to larger and broader surveys of lice from pediculosis capitis occurring in other geographic locations.

Molecular Markers of Pesticide Resistance and Pathogens in Human Head Lice (Phthiraptera: Pediculidae) From Rural Georgia, USA.

Although the head louse, Pediculus humanus capitis De Geer, and body louse, Pediculus humanus humanus L., both have a worldwide distribution, the occurrence of head louse pediculosis appears to be more prevalent in modern societies despite systematic use of various pediculicides. This study tested head lice collected in rural Georgia and body lice collected in Russia for the prevalence of a kdr-biomarker that is associated with permethrin resistance. This study also screened lice for the presence of DNA from Bartonella quintana and Acinetobacter species. The kdr-permethrin resistance biomarker for the T917I mutation was detected by RFLP and PCR in 99.9% of head lice tested from Georgia, whereas only 2.9% of body lice from Russia tested positive for this kdr biomarker. DNA of B. quintana was detected in 10.3% of head lice from Georgia, whereas 84.8% of body lice from Russia tested positive. Acinetobacter DNA was detected in 80.8% (95% CI, 68-89%) of head lice from Georgia and all body lice from Russia tested.