24.8%) DNA were detected in rat fl eas (Xenopsylla cheopis) collected from mice on Oahu Island, H... more 24.8%) DNA were detected in rat fl eas (Xenopsylla cheopis) collected from mice on Oahu Island, Hawaii. The low prevalence of R. typhi on Oahu suggests that R. felis may be a more common cause of rickettsiosis than R. typhi in Hawaii. The Study M. musculus mice were collected during rodent population studies in the leeward and southeast parts of Oahu during the summers of 2004, 2006, and 2007 (Figure). Fleas were combed from each animal, identified as X. cheopis by using standard taxonomic keys, and kept frozen at –70°C until they were sent to the Centers for Disease Control and Prevention (Atlanta, GA, USA) for further analyses. Mice were humanely killed; only brains were removed and frozen. DNA was isolated from each flea by using the Biomek
Rickettsiae closely related to the Malish strain, the reference Rickettsia conorii strain, includ... more Rickettsiae closely related to the Malish strain, the reference Rickettsia conorii strain, include Indian tick typhus rickettsia (ITTR), Israeli spotted fever rickettsia (ISFR), and Astrakhan fever rickettsia (AFR). Although closely related genotypically, they are distinct serotypically. Using multilocus sequence typing (MLST), we have recently found that distinct serotypes may not always represent distinct species within the Rickettsia genus. We investigated the possibility of classifying rickettsiae closely related to R. conorii as R. conorii subspecies as proposed by the ad hoc committee on reconciliation of approaches to bacterial systematics. For this, we first estimated their genotypic variability by using MLST including the sequencing of 5 genes, of 31 rickettsial isolates closely related to R. conorii strain Malish, 1 ITTR isolate, 2 isolates and 3 tick amplicons of AFR, and 2 ISFR isolates. Then, we selected a representative of each MLST genotype and used multi-spacer typin...
Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however,... more Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however, no recent reports of flea-borne rickettsioses are known from adjacent San Bernardino County. Sixty-five opossums (Didelphis virginiana) were trapped in the suburban residential and industrial zones of the southwestern part of San Bernardino County in 2007. Sixty out of 65 opossums were infested with fleas, primarily cat fleas, Ctenocephalides felis (Bouché, 1835). The flea minimum infection rate with Rickettsia felis was 13.3% in pooled samples and the prevalence was 23.7% in single fleas, with two gltA genotypes detected. In spite of historic records of murine typhus in this area, no evidence for circulation of R. typhi in fleas was found during the present study. Factors contributing to the absence of R. typhi in these cat fleas in contrast to its presence in cat fleas from Orange and Los Angeles Counties are unknown and need to be investigated further in San Bernardino County
Rickettsia felis is an emerging human pathogen associated primarily with the cat flea Ctenocephal... more Rickettsia felis is an emerging human pathogen associated primarily with the cat flea Ctenocephalides felis. In this study, we investigated the presence of Rickettsia felis in C. felis from Guatemala and Costa Rica. Ctenocephalides felis were collected directly from dogs and cats, and analyzed by polymerase chain reaction for Rickettsia-specific fragments of 17-kDa protein, OmpA, and citrate synthase genes. Rickettsia DNA was detected in 64% (55 of 86) and 58% (47 of 81) of flea pools in Guatemala and Costa Rica, respectively. Sequencing of gltA fragments identified R. felis genotype URRWXCal2 in samples from both countries, and genotype Rf2125 in Costa Rica. This is the first report of R. felis in Guatemala and of genotype Rf2125 in Costa Rica. The extensive presence of this pathogen in countries of Central America stresses the need for increased awareness and diagnosis
The Journal of Infection in Developing Countries, 2011
Rocky Mountain spotted fever (RMSF) is a tick-borne infection caused by Rickettsia rickettsii. We... more Rocky Mountain spotted fever (RMSF) is a tick-borne infection caused by Rickettsia rickettsii. We report a cluster of fatal cases of RMSF in 2007 in Panama, involving a pregnant woman and two children from the same family. The woman presented with a fever followed by respiratory distress, maculopapular rash, and an eschar at the site from which a tick had been removed. She died four days after disease onset. This is the second published report of an eschar in a patient confirmed by PCR to be infected with R. rickettsii. One month later, the children presented within days of one another with fever and rash and died three and four days after disease onset. The diagnosis was confirmed by immunohistochemistry, PCR and sequencing of the genes of R. rickettsii in tissues obtained at autopsy.
DNA samples from 737 tick pools, representing 6,850 Haemaphysalis longicornis and 51 Dermacentor ... more DNA samples from 737 tick pools, representing 6,850 Haemaphysalis longicornis and 51 Dermacentor nuttalli collected from Hebei Province, China, were analyzed by polymerase chain reaction (PCR) for the presence of spotted fever group Rickettsia. Fifty (6.9%) of 724 H. longicornis in the tick pool were positive, but no positive samples were found in 13 D. nuttalli. Sequence analysis of the partial outer membrane protein A (ompA) genes from the 10 positive samples showed 97.4-99.8% identity, but were different from the homologous sequence of Rickettsia previously deposited in GenBank. Phylogenetic analysis of ompA genes indicated that the Rickettsia detected in this study belonged to a novel haplotype, and formed a clade distinct from Rickettsia heilongjiangii, Rickettsia sibirica, and Rickettsia hulinii in China. The new strain, named Candidatus Rickettsia hebeiii, appears to represent a distinct lineage and could constitute a new species with a minimum prevalence of about 0.7% in H. longicornis from Hebei Province, China.
DNA samples from 737 tick pools, representing 6,850 Haemaphysalis longicornis and 51 Dermacentor ... more DNA samples from 737 tick pools, representing 6,850 Haemaphysalis longicornis and 51 Dermacentor nuttalli collected from Hebei Province, China, were analyzed by polymerase chain reaction (PCR) for the presence of spotted fever group Rickettsia. Fifty (6.9%) of 724 H. longicornis in the tick pool were positive, but no positive samples were found in 13 D. nuttalli. Sequence analysis of the partial outer membrane protein A (ompA) genes from the 10 positive samples showed 97.4-99.8% identity, but were different from the homologous sequence of Rickettsia previously deposited in GenBank. Phylogenetic analysis of ompA genes indicated that the Rickettsia detected in this study belonged to a novel haplotype, and formed a clade distinct from Rickettsia heilongjiangii, Rickettsia sibirica, and Rickettsia hulinii in China. The new strain, named Candidatus Rickettsia hebeiii, appears to represent a distinct lineage and could constitute a new species with a minimum prevalence of about 0.7% in H. longicornis from Hebei Province, China.
Rickettsialpox is an urban zoonosis caused by Rickettsia akari. To date R. akari is the only well... more Rickettsialpox is an urban zoonosis caused by Rickettsia akari. To date R. akari is the only well-characterized mite-borne member of the spotted fever group. It is transmitted by the mouse mite, Liponyssoides sanguineus, commonly found on peridomestic rodents. While the disease was first discovered in New York City in 1946, a few years later a similar outbreak occurred in the Ukraine SSR. Numerous serosurveys and diagnosis of sporadic cases of rickettsialpox suggest its global distribution; however, the actual contemporary geography of rickettsialpox and its incidence are unknown. Rickettsialpox is characterized by the classic clinical triad found in rickettsioses of a black eschar, high fever, and rash but the latter is atypical as it is papulovesicular. Dermatological manifestations and the progression of rickettsialpox may mimic other infectious and noninfectious syndromes, including sexually transmitted diseases. The purpose of this review is to increase awareness of this unique...
24.8%) DNA were detected in rat fl eas (Xenopsylla cheopis) collected from mice on Oahu Island, H... more 24.8%) DNA were detected in rat fl eas (Xenopsylla cheopis) collected from mice on Oahu Island, Hawaii. The low prevalence of R. typhi on Oahu suggests that R. felis may be a more common cause of rickettsiosis than R. typhi in Hawaii. The Study M. musculus mice were collected during rodent population studies in the leeward and southeast parts of Oahu during the summers of 2004, 2006, and 2007 (Figure). Fleas were combed from each animal, identified as X. cheopis by using standard taxonomic keys, and kept frozen at –70°C until they were sent to the Centers for Disease Control and Prevention (Atlanta, GA, USA) for further analyses. Mice were humanely killed; only brains were removed and frozen. DNA was isolated from each flea by using the Biomek
Rickettsiae closely related to the Malish strain, the reference Rickettsia conorii strain, includ... more Rickettsiae closely related to the Malish strain, the reference Rickettsia conorii strain, include Indian tick typhus rickettsia (ITTR), Israeli spotted fever rickettsia (ISFR), and Astrakhan fever rickettsia (AFR). Although closely related genotypically, they are distinct serotypically. Using multilocus sequence typing (MLST), we have recently found that distinct serotypes may not always represent distinct species within the Rickettsia genus. We investigated the possibility of classifying rickettsiae closely related to R. conorii as R. conorii subspecies as proposed by the ad hoc committee on reconciliation of approaches to bacterial systematics. For this, we first estimated their genotypic variability by using MLST including the sequencing of 5 genes, of 31 rickettsial isolates closely related to R. conorii strain Malish, 1 ITTR isolate, 2 isolates and 3 tick amplicons of AFR, and 2 ISFR isolates. Then, we selected a representative of each MLST genotype and used multi-spacer typin...
Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however,... more Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however, no recent reports of flea-borne rickettsioses are known from adjacent San Bernardino County. Sixty-five opossums (Didelphis virginiana) were trapped in the suburban residential and industrial zones of the southwestern part of San Bernardino County in 2007. Sixty out of 65 opossums were infested with fleas, primarily cat fleas, Ctenocephalides felis (Bouché, 1835). The flea minimum infection rate with Rickettsia felis was 13.3% in pooled samples and the prevalence was 23.7% in single fleas, with two gltA genotypes detected. In spite of historic records of murine typhus in this area, no evidence for circulation of R. typhi in fleas was found during the present study. Factors contributing to the absence of R. typhi in these cat fleas in contrast to its presence in cat fleas from Orange and Los Angeles Counties are unknown and need to be investigated further in San Bernardino County
Rickettsia felis is an emerging human pathogen associated primarily with the cat flea Ctenocephal... more Rickettsia felis is an emerging human pathogen associated primarily with the cat flea Ctenocephalides felis. In this study, we investigated the presence of Rickettsia felis in C. felis from Guatemala and Costa Rica. Ctenocephalides felis were collected directly from dogs and cats, and analyzed by polymerase chain reaction for Rickettsia-specific fragments of 17-kDa protein, OmpA, and citrate synthase genes. Rickettsia DNA was detected in 64% (55 of 86) and 58% (47 of 81) of flea pools in Guatemala and Costa Rica, respectively. Sequencing of gltA fragments identified R. felis genotype URRWXCal2 in samples from both countries, and genotype Rf2125 in Costa Rica. This is the first report of R. felis in Guatemala and of genotype Rf2125 in Costa Rica. The extensive presence of this pathogen in countries of Central America stresses the need for increased awareness and diagnosis
The Journal of Infection in Developing Countries, 2011
Rocky Mountain spotted fever (RMSF) is a tick-borne infection caused by Rickettsia rickettsii. We... more Rocky Mountain spotted fever (RMSF) is a tick-borne infection caused by Rickettsia rickettsii. We report a cluster of fatal cases of RMSF in 2007 in Panama, involving a pregnant woman and two children from the same family. The woman presented with a fever followed by respiratory distress, maculopapular rash, and an eschar at the site from which a tick had been removed. She died four days after disease onset. This is the second published report of an eschar in a patient confirmed by PCR to be infected with R. rickettsii. One month later, the children presented within days of one another with fever and rash and died three and four days after disease onset. The diagnosis was confirmed by immunohistochemistry, PCR and sequencing of the genes of R. rickettsii in tissues obtained at autopsy.
DNA samples from 737 tick pools, representing 6,850 Haemaphysalis longicornis and 51 Dermacentor ... more DNA samples from 737 tick pools, representing 6,850 Haemaphysalis longicornis and 51 Dermacentor nuttalli collected from Hebei Province, China, were analyzed by polymerase chain reaction (PCR) for the presence of spotted fever group Rickettsia. Fifty (6.9%) of 724 H. longicornis in the tick pool were positive, but no positive samples were found in 13 D. nuttalli. Sequence analysis of the partial outer membrane protein A (ompA) genes from the 10 positive samples showed 97.4-99.8% identity, but were different from the homologous sequence of Rickettsia previously deposited in GenBank. Phylogenetic analysis of ompA genes indicated that the Rickettsia detected in this study belonged to a novel haplotype, and formed a clade distinct from Rickettsia heilongjiangii, Rickettsia sibirica, and Rickettsia hulinii in China. The new strain, named Candidatus Rickettsia hebeiii, appears to represent a distinct lineage and could constitute a new species with a minimum prevalence of about 0.7% in H. longicornis from Hebei Province, China.
DNA samples from 737 tick pools, representing 6,850 Haemaphysalis longicornis and 51 Dermacentor ... more DNA samples from 737 tick pools, representing 6,850 Haemaphysalis longicornis and 51 Dermacentor nuttalli collected from Hebei Province, China, were analyzed by polymerase chain reaction (PCR) for the presence of spotted fever group Rickettsia. Fifty (6.9%) of 724 H. longicornis in the tick pool were positive, but no positive samples were found in 13 D. nuttalli. Sequence analysis of the partial outer membrane protein A (ompA) genes from the 10 positive samples showed 97.4-99.8% identity, but were different from the homologous sequence of Rickettsia previously deposited in GenBank. Phylogenetic analysis of ompA genes indicated that the Rickettsia detected in this study belonged to a novel haplotype, and formed a clade distinct from Rickettsia heilongjiangii, Rickettsia sibirica, and Rickettsia hulinii in China. The new strain, named Candidatus Rickettsia hebeiii, appears to represent a distinct lineage and could constitute a new species with a minimum prevalence of about 0.7% in H. longicornis from Hebei Province, China.
Rickettsialpox is an urban zoonosis caused by Rickettsia akari. To date R. akari is the only well... more Rickettsialpox is an urban zoonosis caused by Rickettsia akari. To date R. akari is the only well-characterized mite-borne member of the spotted fever group. It is transmitted by the mouse mite, Liponyssoides sanguineus, commonly found on peridomestic rodents. While the disease was first discovered in New York City in 1946, a few years later a similar outbreak occurred in the Ukraine SSR. Numerous serosurveys and diagnosis of sporadic cases of rickettsialpox suggest its global distribution; however, the actual contemporary geography of rickettsialpox and its incidence are unknown. Rickettsialpox is characterized by the classic clinical triad found in rickettsioses of a black eschar, high fever, and rash but the latter is atypical as it is papulovesicular. Dermatological manifestations and the progression of rickettsialpox may mimic other infectious and noninfectious syndromes, including sexually transmitted diseases. The purpose of this review is to increase awareness of this unique...
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Papers by Marina Eremeeva