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1.
J Infect Dis ; 2024 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-39432903

RESUMEN

The etiologic agent of Pacific Coast tick fever (PCTF), a moderately severe tickborne illness that resembles Rocky Mountain spotted fever (RMSF), was first isolated in 1966 from specimens of Dermacentor occidentalis (the Pacific Coast tick) obtained in California. For several decades, this bacterium was identified ambiguously as the unclassified spotted fever group Rickettsia species 364-D, Rickettsia 364, or Rickettsia philipii. However, none of these epithets satisfied criteria of formal bacterial nomenclature. Data developed from mouse serotyping studies performed 45 years ago, and multi-locus sequence typing several decades later, indicated that this bacterium was similar to, but distinct from isolates of Rickettsia rickettsii, the etiological agent of RMSF. We applied an integrative taxonomic approach, combining phenotypic, ecological, and clinical data with whole genome sequencing of 11 contemporary isolates of this pathogen to identify it as a distinct subspecies of R. rickettsii, and propose the name Rickettsia rickettsii subsp. californica subsp. nov.

2.
J Infect Dis ; 229(Supplement_2): S219-S228, 2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38243606

RESUMEN

BACKGROUND: Pathology and Monkeypox virus (MPXV) tissue tropism in severe and fatal human mpox is not thoroughly described but can help elucidate the disease pathogenesis and the role of coinfections in immunocompromised patients. METHODS: We analyzed biopsy and autopsy tissues from 22 patients with severe or fatal outcomes to characterize pathology and viral antigen and DNA distribution in tissues by immunohistochemistry and in situ hybridization. Tissue-based testing for coinfections was also performed. RESULTS: Mucocutaneous lesions showed necrotizing and proliferative epithelial changes. Deceased patients with autopsy tissues evaluated had digestive tract lesions, and half had systemic tissue necrosis with thrombotic vasculopathy in lymphoid tissues, lung, or other solid organs. Half also had bronchopneumonia, and one-third had acute lung injury. All cases had MPXV antigen and DNA detected in tissues. Coinfections were identified in 5 of 16 (31%) biopsy and 4 of 6 (67%) autopsy cases. CONCLUSIONS: Severe mpox in immunocompromised patients is characterized by extensive viral infection of tissues and viremic dissemination that can progress despite available therapeutics. Digestive tract and lung involvement are common and associated with prominent histopathological and clinical manifestations. Coinfections may complicate mpox diagnosis and treatment. Significant viral DNA (likely correlating to infectious virus) in tissues necessitates enhanced biosafety measures in healthcare and autopsy settings.


Asunto(s)
Coinfección , Mpox , Humanos , Monkeypox virus , Huésped Inmunocomprometido , Antígenos Virales , ADN Viral
3.
Emerg Infect Dis ; 30(10): 2208-2211, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39320216

RESUMEN

We document a case of Rickettsia parkeri rickettsiosis in a patient in Connecticut, USA, who became ill after a bite from a Gulf Coast tick (Amblyomma maculatum). We used PCR to amplify R. parkeri DNA from the detached tick. The patient showed a 4-fold rise in IgG reactive with R. parkeri antigens.


Asunto(s)
Amblyomma , Infecciones por Rickettsia , Rickettsia , Rickettsia/genética , Rickettsia/aislamiento & purificación , Rickettsia/clasificación , Animales , Humanos , Infecciones por Rickettsia/microbiología , Infecciones por Rickettsia/transmisión , Infecciones por Rickettsia/diagnóstico , Amblyomma/microbiología , Connecticut , Mordeduras de Garrapatas , Masculino , Femenino , Anticuerpos Antibacterianos/sangre
4.
Emerg Infect Dis ; 30(11): 2231-2240, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39447135

RESUMEN

Rocky Mountain spotted fever (RMSF) is a severe tickborne disease that can reach epidemic proportions in communities with certain social and ecologic risk factors. In some areas, the case-fatality rate of brown dog tick-associated RMSF is up to 50%. Because of the spread of brown dog tick-associated RMSF in the southwestern United States and northern Mexico, the disease has the potential to emerge and become endemic in other communities that have large populations of free-roaming dogs, brown dog ticks, limited resources, and low provider awareness of the disease. By using a One Health approach, interdisciplinary teams can identify communities at risk and prevent severe or fatal RMSF in humans before cases occur. We have developed a conceptual framework for RMSF prevention to enable communities to identify their RMSF risk level and implement prevention and control strategies.


Asunto(s)
Fiebre Maculosa de las Montañas Rocosas , Animales , Fiebre Maculosa de las Montañas Rocosas/prevención & control , Fiebre Maculosa de las Montañas Rocosas/transmisión , Fiebre Maculosa de las Montañas Rocosas/epidemiología , Fiebre Maculosa de las Montañas Rocosas/veterinaria , Perros , Humanos , Enfermedades de los Perros/prevención & control , Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/parasitología , Rhipicephalus sanguineus , Factores de Riesgo
5.
Emerg Infect Dis ; 30(7): 1463-1466, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38861505

RESUMEN

We describe 5 children who had Rocky Mountain spotted fever (RMSF) and manifested clinical symptoms similar to multisystem inflammatory syndrome in Sonora, Mexico, where RMSF is hyperendemic. Physicians should consider RMSF in differential diagnoses of hospitalized patients with multisystem inflammatory syndrome to prevent illness and death caused by rickettsial disease.


Asunto(s)
Fiebre Maculosa de las Montañas Rocosas , Síndrome de Respuesta Inflamatoria Sistémica , Humanos , México , Síndrome de Respuesta Inflamatoria Sistémica/diagnóstico , Niño , Masculino , Fiebre Maculosa de las Montañas Rocosas/diagnóstico , Femenino , Diagnóstico Diferencial , Preescolar , Adolescente , Hospitalización
6.
Emerg Infect Dis ; 30(7): 1459-1462, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38916804

RESUMEN

Spotted fever rickettsiosis is rarely observed in solid organ transplant recipients, and all previously reported cases have been associated with tick bite months to years after transplantation. We describe a kidney transplant recipient in North Carolina, USA, who had a moderately severe Rickettsia parkeri infection develop during the immediate posttransplant period.


Asunto(s)
Trasplante de Riñón , Infecciones por Rickettsia , Rickettsia , Humanos , Persona de Mediana Edad , Antibacterianos/uso terapéutico , Trasplante de Riñón/efectos adversos , North Carolina , Rickettsia/genética , Rickettsia/aislamiento & purificación , Infecciones por Rickettsia/diagnóstico , Infecciones por Rickettsia/microbiología , Receptores de Trasplantes
7.
Emerg Infect Dis ; 29(9): 1904-1907, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37610264

RESUMEN

We detected the DNA of an Anaplasma bovis-like bacterium in blood specimens from 4 patients from the United States with suspected tickborne illnesses. Initial molecular characterization of this novel agent reveals identity to A. bovis-like bacteria detected in Dermacentor variabilis ticks collected from multiple US states.


Asunto(s)
Anaplasma , Anaplasmosis , Humanos , Anaplasma/genética , Estados Unidos/epidemiología , Dermacentor/microbiología , Anaplasmosis/diagnóstico
8.
J Infect Dis ; 223(5): 752-764, 2021 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-33502471

RESUMEN

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic continues to produce substantial morbidity and mortality. To understand the reasons for the wide-spectrum complications and severe outcomes of COVID-19, we aimed to identify cellular targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) tropism and replication in various tissues. METHODS: We evaluated RNA extracted from formalin-fixed, paraffin-embedded autopsy tissues from 64 case patients (age range, 1 month to 84 years; 21 COVID-19 confirmed, 43 suspected COVID-19) by SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR). For cellular localization of SARS-CoV-2 RNA and viral characterization, we performed in situ hybridization (ISH), subgenomic RNA RT-PCR, and whole-genome sequencing. RESULTS: SARS-CoV-2 was identified by RT-PCR in 32 case patients (21 COVID-19 confirmed, 11 suspected). ISH was positive in 20 and subgenomic RNA RT-PCR was positive in 17 of 32 RT-PCR-positive case patients. SARS-CoV-2 RNA was localized by ISH in hyaline membranes, pneumocytes, and macrophages of lungs; epithelial cells of airways; and endothelial cells and vessel walls of brain stem, leptomeninges, lung, heart, liver, kidney, and pancreas. The D614G variant was detected in 9 RT-PCR-positive case patients. CONCLUSIONS: We identified cellular targets of SARS-CoV-2 tropism and replication in the lungs and airways and demonstrated its direct infection in vascular endothelium. This work provides important insights into COVID-19 pathogenesis and mechanisms of severe outcomes.


Asunto(s)
COVID-19/virología , Endotelio Vascular/virología , Sistema Respiratorio/virología , SARS-CoV-2/fisiología , Replicación Viral , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Autopsia , COVID-19/complicaciones , Prueba de Ácido Nucleico para COVID-19 , Niño , Preescolar , Femenino , Humanos , Hibridación in Situ , Lactante , Pulmón/virología , Masculino , Persona de Mediana Edad , ARN Viral/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación , Tropismo Viral , Secuenciación Completa del Genoma , Adulto Joven
9.
Infect Immun ; 89(4)2021 03 17.
Artículo en Inglés | MEDLINE | ID: mdl-33495273

RESUMEN

Rickettsia rickettsii, the etiological agent of Rocky Mountain spotted fever (RMSF), a life-threatening tick-borne disease that affects humans and various animal species, has been recognized in medicine and science for more than 100 years. Isolate-dependent differences in virulence of R. rickettsii have been documented for many decades; nonetheless, the specific genetic and phenotypic factors responsible for these differences have not been characterized. Using in vivo and in vitro methods, we identified multiple phenotypic differences among six geographically distinct isolates of R. rickettsii, representing isolates from the United States, Costa Rica, and Brazil. Aggregate phenotypic data, derived from growth in Vero E6 cells and from clinical and pathological characteristics following infection of male guinea pigs (Cavia porcellus), allowed separation of these isolates into three categories: nonvirulent (Iowa), mildly virulent (Sawtooth and Gila), and highly virulent (Sheila SmithT, Costa Rica, and Taiaçu). Transcriptional profiles of 11 recognized or putative virulence factors confirmed the isolate-dependent differences between mildly and highly virulent isolates. These data corroborate previous qualitative assessments of strain virulence and suggest further that a critical and previously underappreciated balance between bacterial growth and host immune response could leverage strain pathogenicity. Also, this work provides insight into isolate-specific microbiological factors that contribute to the outcome of RMSF and confirms the hypothesis that distinct rickettsial isolates also differ phenotypically, which could influence the severity of disease in vertebrate hosts.


Asunto(s)
Interacciones Huésped-Patógeno/genética , Rickettsia rickettsii/fisiología , Fiebre Maculosa de las Montañas Rocosas/genética , Fiebre Maculosa de las Montañas Rocosas/microbiología , Animales , Carga Bacteriana , Biomarcadores , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Regulación Bacteriana de la Expresión Génica , Cobayas , Humanos , Inmunohistoquímica , Masculino , Rickettsia rickettsii/clasificación , Fiebre Maculosa de las Montañas Rocosas/diagnóstico , Evaluación de Síntomas , Virulencia/genética , Factores de Virulencia/genética
10.
Emerg Infect Dis ; 27(5): 1517-1519, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33704045

RESUMEN

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shares common clinicopathologic features with other severe pulmonary illnesses. Hantavirus pulmonary syndrome was diagnosed in 2 patients in Arizona, USA, suspected of dying from infection with SARS-CoV-2. Differential diagnoses and possible co-infections should be considered for cases of respiratory distress during the SARS-CoV-2 pandemic.


Asunto(s)
COVID-19 , Enfermedades Transmisibles Emergentes , Síndrome Pulmonar por Hantavirus , Arizona , Enfermedades Transmisibles Emergentes/epidemiología , Humanos , SARS-CoV-2
11.
Artículo en Inglés | MEDLINE | ID: mdl-34214027

RESUMEN

A previously unrecognized Rickettsia species was isolated in 1976 from a pool of Ixodes pacificus ticks collected in 1967 from Tillamook County, Oregon, USA. The isolate produced low fever and mild scrotal oedema following intraperitoneal injection into male guinea pigs (Cavia porcellus). Subsequent serotyping characterized this isolate as distinct from recognized typhus and spotted fever group Rickettsia species; nonetheless, the isolate remained unevaluated by molecular techniques and was not identified to species level for the subsequent 30 years. Ixodes pacificus is the most frequently identified human-biting tick in the western United States, and as such, formal identification and characterization of this potentially pathogenic Rickettsia species is warranted. Whole-genome sequencing of the Tillamook isolate revealed a genome 1.43 Mbp in size with 32.4 mol% G+C content. Maximum-likelihood phylogeny of core proteins places it in the transitional group of Rickettsia basal to both Rickettsia felis and Rickettsia asembonensis. It is distinct from existing named species, with maximum average nucleotide identity of 95.1% to R. asembonensis and maximum digital DNA-DNA hybridization score similarity to R. felis at 80.1%. The closest similarity at the 16S rRNA gene (97.9%) and sca4 (97.5%/97.6% respectively) is to Candidatus 'Rickettsia senegalensis' and Rickettsia sp. cf9, both isolated from cat fleas (Ctenocephalides felis). We characterized growth at various temperatures and in multiple cell lines. The Tillamook isolate grows aerobically in Vero E6, RF/6A and DH82 cells, and growth is rapid at 28 °C and 32 °C. Using accepted genomic criteria, we propose the name Rickettsia tillamookensis sp. nov., with the type strain Tillamook 23. Strain Tillamook 23 is available from the Centers for Disease Control and Prevention Rickettsial Isolate Reference Collection (WDCM 1093), Atlanta, GA, USA (CRIRC accession number RTI001T) and the Collection de Souches de l'Unité des Rickettsies (WDCM 875), Marseille, France (CSUR accession number R5043). Using accepted genomic criteria, we propose the name Rickettsia tillamookensis sp. nov., with the type strain Tillamook 23 (=CRIRC RTI001=R5043).


Asunto(s)
Ixodes/microbiología , Filogenia , Rickettsia/clasificación , Animales , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Cobayas , Masculino , Oregon , ARN Ribosómico 16S/genética , Rickettsia/aislamiento & purificación , Análisis de Secuencia de ADN
12.
J Infect Dis ; 221(8): 1371-1378, 2020 03 28.
Artículo en Inglés | MEDLINE | ID: mdl-31267128

RESUMEN

BACKGROUND: Since 2000, the reported prevalence of tick-borne spotted fever rickettsiosis has increased considerably. We compared the level of antibody reactivity among healthy blood donors from 2 widely separated regions of the United States and evaluated the impact of antibody prevalence on public health surveillance in one of these regions. METHODS: Donor serum samples were evaluated by indirect immunofluorescence antibody assay to identify immunoglobulin G (IgG) antibodies reactive with Rickettsia rickettsii. The Georgia Department of Public Health (GDPH) analyzed characteristics of cases from 2016 surveillance data to evaluate the utility of laboratory surveillance for case assessment. RESULTS: Of the Georgia donors (n = 1493), 11.1% demonstrated antibody titers reactive with R. rickettsii at titers ≥64, whereas 6.3% of donors from Oregon and Washington (n = 1511) were seropositive. Most seropositive donors had a titer of 64; only 3.1% (n = 93) of all donors had titers ≥128. During 2016, GDPH interviewed 243 seropositive case patients; only 28% (n = 69) met inclusion criteria in the national case definition for spotted fever rickettsiosis. CONCLUSIONS: These findings suggest that a single IgG antibody titer is an unreliable measure of diagnosis and could inaccurately affect surveillance estimates that define magnitude and clinical characteristics of Rocky Mountain spotted fever and other spotted fever rickettsioses.


Asunto(s)
Anticuerpos Antibacterianos/sangre , Anticuerpos Antibacterianos/inmunología , Rickettsia rickettsii/inmunología , Fiebre Maculosa de las Montañas Rocosas/inmunología , Fiebre Maculosa de las Montañas Rocosas/microbiología , Rickettsiosis Exantemáticas/inmunología , Rickettsiosis Exantemáticas/microbiología , Adolescente , Adulto , Anciano , Animales , Vectores Arácnidos/microbiología , Donantes de Sangre , Femenino , Georgia , Humanos , Inmunoglobulina G/inmunología , Pruebas Inmunológicas/métodos , Masculino , Persona de Mediana Edad , Oregon , Infecciones por Rickettsia/inmunología , Infecciones por Rickettsia/microbiología , Estados Unidos , Washingtón , Adulto Joven
13.
Exp Appl Acarol ; 82(4): 543-557, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33091146

RESUMEN

The Amblyomma maculatum Koch group of ixodid ticks consists of three species: A. maculatum, A. triste, and A. tigrinum. However, since Koch described this group in 1844, the systematics of its members has been the subject of ongoing debate. This is especially true of A. maculatum and A. triste; recent molecular analyses reveal insufficient genetic divergence to separate these as distinct species. Further confounding this issue is the discovery in 2014 of A. maculatum group ticks in southern Arizona (AZ), USA, that share morphological characteristics with both A. triste and A. maculatum. To biologically evaluate the identity of A. maculatum group ticks from southern Arizona, we analyzed the reproductive compatibility between specimens of A. maculatum group ticks collected from Georgia (GA), USA, and southern Arizona. Female ticks from both Arizona and Georgia were mated with males from both the Georgia and Arizona Amblyomma populations, creating two homologous and two heterologous F1 cohorts of ticks: GA ♀/GA ♂, AZ ♀/AZ ♂, GA ♀/AZ ♂, and AZ ♀/GA ♂. Each cohort was maintained separately into the F2 generation with F1 females mating only with F1 males from their same cohort. Survival and fecundity parameters were measured for all developmental stages. The observed survival parameters for heterologous cohorts were comparable to those of the homologous cohorts through the F1 generation. However, the F1 heterologous females produced F2 egg clutches that did not hatch, thus indicating that the Arizona and Georgia populations of A. maculatum group ticks tested here represent different biological species.


Asunto(s)
Ixodidae , Rickettsia , Garrapatas , Amblyomma , Animales , Arizona , Femenino , Georgia , Ixodidae/genética , Masculino
14.
Emerg Infect Dis ; 25(4): 836-838, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30882330

RESUMEN

We report Rickettsia parkeri and Candidatus Rickettsia andeanae in ticks of the Amblyomma maculatum group collected from dogs in Sonora, Mexico. Molecular characterization of these bacteria was accomplished by DNA amplification and sequence analysis of portions of the rickettsial genes gltA, htrA, ompA, and ompB.


Asunto(s)
Rickettsia , Infestaciones por Garrapatas/epidemiología , Garrapatas/microbiología , Animales , Genes Bacterianos , Humanos , México/epidemiología , Tipificación Molecular , Reacción en Cadena de la Polimerasa , Rickettsia/clasificación , Rickettsia/genética , Rickettsia/aislamiento & purificación , Análisis de Secuencia de ADN
15.
Emerg Infect Dis ; 25(12): 2315-2317, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31742525

RESUMEN

We found Rickettsia parkeri in Amblyomma ovale ticks collected in Veracruz, Mexico, in 2018. We sequenced gene segments of gltA, htrA, sca0, and sca5; phylogenetic reconstruction revealed near-complete identity with R. parkeri strain Atlantic Rainforest. Enhanced surveillance is needed in Mexico to determine the public health relevance of this bacterium.


Asunto(s)
Rickettsia/clasificación , Rickettsia/genética , Infestaciones por Garrapatas/epidemiología , Garrapatas/microbiología , Animales , Femenino , Genes Bacterianos , Masculino , México/epidemiología , Filogenia , Vigilancia en Salud Pública
16.
J Clin Microbiol ; 58(1)2019 12 23.
Artículo en Inglés | MEDLINE | ID: mdl-31666366

RESUMEN

Pacific Coast tick fever is a febrile illness associated with the bite of Dermacentor occidentalis and results from an infection due to the intracellular pathogen Rickettsia 364D (also known by the proposed name "Rickettsia philipii"). Current molecular methods for the detection of this pathogen rely on the amplification of a conserved spotted fever group rickettsial gene (ompA) followed by DNA sequencing of the amplicon to identify the species. This work describes the development of a Rickettsia 364D-specific TaqMan assay to simplify and accelerate the detection and identification processes. The assay demonstrated a sensitivity of 1 genomic copy per 4-µl sample and is highly specific for Rickettsia 364D. The utility of this assay for ecological and diagnostic samples was evaluated using banked specimens collected in a single-blind manner and yielded a clinical sensitivity and specificity of 100%. In conclusion, we describe the development and evaluation of a novel TaqMan real-time PCR assay for the detection and identification of Rickettsia 364D suitable for ecological and diagnostic applications.


Asunto(s)
Reacción en Cadena en Tiempo Real de la Polimerasa , Infecciones por Rickettsia/diagnóstico , Infecciones por Rickettsia/microbiología , Rickettsia/genética , Enfermedades por Picaduras de Garrapatas/diagnóstico , Enfermedades por Picaduras de Garrapatas/microbiología , Animales , Dermacentor/microbiología , Humanos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/normas , Infecciones por Rickettsia/transmisión , Sensibilidad y Especificidad , Enfermedades por Picaduras de Garrapatas/transmisión
17.
Emerg Infect Dis ; 24(6): 1108-1111, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29774838

RESUMEN

During a study to identify zoonotic pathogens in northwestern Mexico, we detected the presence of a rickettsial agent in Dermacentor parumapertus ticks from black-tailed jackrabbits (Lepus californicus). Comparison of 4 gene sequences (gltA, htrA, ompA, and ompB) of this agent showed 99%-100% identity with sequences of Rickettsia parkeri.


Asunto(s)
Vectores Arácnidos/microbiología , Dermacentor/microbiología , Infecciones por Rickettsia/epidemiología , Infecciones por Rickettsia/microbiología , Rickettsia/clasificación , Rickettsia/genética , Animales , Femenino , Genes Bacterianos , Humanos , Masculino , México/epidemiología , Filogenia , Rickettsia/aislamiento & purificación , Infecciones por Rickettsia/transmisión
18.
Appl Environ Microbiol ; 84(8)2018 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-29439989

RESUMEN

The bacterium Rickettsia parkeri has been reported to infect ticks of the "Amblyomma maculatum species complex" in the New World, where it causes spotted fever illness in humans. In South America, three additional rickettsial strains, namely, Atlantic rainforest, NOD, and Parvitarsum, have been isolated from the ticks Amblyomma ovale, Amblyomma nodosum, and Amblyomma parvitarsum, respectively. These three strains are phylogenetically closely related to R. parkeri, Rickettsia africae, and Rickettsia sibirica Herein, we performed a robust phylogenetic analysis encompassing 5 genes (gltA, ompA, virB4, dnaA, and dnaK) and 3 intergenic spacers (mppE-pur, rrl-rrf-ITS, and rpmE-tRNAfMet) from 41 rickettsial isolates, including different isolates of R. parkeri, R. africae, R. sibirica, Rickettsia conorii, and strains Atlantic rainforest, NOD, and Parvitarsum. In our phylogenetic analyses, all New World isolates grouped in a major clade distinct from the Old World Rickettsia species (R. conorii, R. sibirica, and R. africae). This New World clade was subdivided into the following 4 clades: the R. parkerisensu stricto clade, comprising the type strain Maculatum 20 and all other isolates of R. parkeri from North and South America, associated with ticks of the A. maculatum species complex; the strain NOD clade, comprising two South American isolates from A. nodosum ticks; the Parvitarsum clade, comprising two South American isolates from A. parvitarsum ticks; and the strain Atlantic rainforest clade, comprising six South American isolates from the A. ovale species complex (A. ovale or Amblyomma aureolatum). Under such evidences, we propose that strains Atlantic rainforest, NOD, and Parvitarsum are South American strains of R. parkeriIMPORTANCE Since the description of Rickettsia parkeri infecting ticks of the "Amblyomma maculatum species complex" and humans in the New World, three novel phylogenetic close-related rickettsial isolates were reported in South America. Herein, we provide genetic evidence that these novel isolates, namely, strains Atlantic rainforest, NOD, and Parvitarsum, are South American strains of R. parkeri. Interestingly, each of these R. parkeri strains seems to be primarily associated with a tick species group, namely, R. parkerisensu stricto with the "Amblyomma maculatum species group," R. parkeri strain NOD with Amblyomma nodosum, R. parkeri strain Parvitarsum with Amblyomma parvitarsum, and R. parkeri strain Atlantic rainforest with the "Amblyomma ovale species group." Such rickettsial strain-tick species specificity suggests a coevolution of each tick-strain association. Finally, because R. parkerisensu stricto and R. parkeri strain Atlantic rainforest are human pathogens, the potential of R. parkeri strains NOD and Parvitarsum to be human pathogens cannot be discarded.


Asunto(s)
Ixodidae/microbiología , Filogenia , Rickettsia/aislamiento & purificación , Américas , Animales , ADN Bacteriano/análisis , ADN Intergénico/análisis , Genes Bacterianos , Interacciones Huésped-Patógeno , Rickettsia/clasificación , Rickettsia/genética , Análisis de Secuencia de ADN
20.
J Infect Dis ; 215(1): 64-69, 2017 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-27226206

RESUMEN

Here we describe clinicopathologic features of Ebola virus disease in pregnancy. One woman infected with Sudan virus in Gulu, Uganda, in 2000 had a stillbirth and survived, and another woman infected with Bundibugyo virus had a live birth with maternal and infant death in Isiro, the Democratic Republic of the Congo in 2012. Ebolavirus antigen was seen in the syncytiotrophoblast and placental maternal mononuclear cells by immunohistochemical analysis, and no antigen was seen in fetal placental stromal cells or fetal organs. In the Gulu case, ebolavirus antigen localized to malarial parasite pigment-laden macrophages. These data suggest that trophoblast infection may be a mechanism of transplacental ebolavirus transmission.


Asunto(s)
Ebolavirus/aislamiento & purificación , Fiebre Hemorrágica Ebola/patología , Fiebre Hemorrágica Ebola/virología , Complicaciones Infecciosas del Embarazo/patología , Complicaciones Infecciosas del Embarazo/virología , Adulto , Anticuerpos Antivirales/sangre , Antígenos Virales/inmunología , Antígenos Virales/aislamiento & purificación , República Democrática del Congo , Ebolavirus/química , Ebolavirus/genética , Ebolavirus/inmunología , Femenino , Fiebre Hemorrágica Ebola/inmunología , Fiebre Hemorrágica Ebola/transmisión , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Inmunohistoquímica , Macrófagos/parasitología , Macrófagos/ultraestructura , Macrófagos/virología , Malaria/complicaciones , Malaria/inmunología , Malaria/virología , Microscopía Electrónica de Transmisión , Placenta/ultraestructura , Placenta/virología , Reacción en Cadena de la Polimerasa , Embarazo , Complicaciones Infecciosas del Embarazo/inmunología , Complicaciones Infecciosas del Embarazo/parasitología , Mortinato , Células del Estroma/ultraestructura , Células del Estroma/virología , Trofoblastos/parasitología , Trofoblastos/ultraestructura , Trofoblastos/virología
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