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1.
Rev Bras Parasitol Vet ; 31(2): e001322, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35648978

RESUMO

Tick-borne pathogens belong to one of the two main groups of occupational biohazards, and occupational exposure to such agents puts soldiers at risk of zoonotic infections, such as those caused by rickettsiae. There are few studies on acarological fauna and occupational risk in military areas in Brazil. Thus, the present study aimed to analyze the diversity of ticks present in the military training areas of municipalities in the Southeast Region of Brazil. The ticks were collected from the selected areas using the dragging and flagging techniques as well as by visual detection on the operators' clothing, and environmental information was also recorded. A total of ten species were collected from the 66 surveyed areas, belonging to five genera and nine species: Amblyomma sculptum, Amblyomma dubitatum, Amblyomma brasiliense, Amblyomma longirostre, Amblyomma aureolatum, Dermacentor nitens, Rhipicephalus spp., Ixodes spp. and Haemaphysalis spp. The frequent presence of tick species in military training areas along with traces and sightings of wild animals, most commonly capybaras (Hydrochoerus hydrochaeris), in most of the studied areas, indicates high levels of exposure of the military to tick vectors of spotted fever group rickettsiae and the possible occurrence of infections among the troops.


Assuntos
Ixodidae , Militares , Rickettsia , Carrapatos , Amblyomma , Animais , Brasil/epidemiologia , Humanos , Roedores
2.
Trop Anim Health Prod ; 54(4): 199, 2022 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-35668327

RESUMO

Rickettsiosis is considered an emerging/re-emerging vector-borne disease that causes significant public health threats. Ticks are reservoirs and vectors of Rickettsia having a significant role in the transmission of rickettsiae. In Portugal, little is known about tick-borne Rickettsia species in sheep. Therefore, this study aimed to investigate rickettsiae infection in ticks and their sheep host from 27 farms in four districts of central Portugal, to clarify the role of the sheep host in the circulation of this zoonotic agent. Between March and May 2021, EDTA blood samples (n = 100) of healthy grazing sheep and their ticks (n = 100, one tick per animal) were collected during a herd health program in central Portugal. Obtained ticks were identified as Rhipicephalus sanguineus sensu lato by PCR targeting a partial sequence of 16S rRNA gene followed by sequence analysis. Rhipicephalus sanguineus s.l. and host sheep blood were tested for the presence of Rickettsia spp. by PCR targeting a partial sequence of ompB and ompA genes. From a total of 100 paired R. sanguineus s.l. and host sheep, Rickettsia massiliae was detected in 62 ticks and 35 grazing sheep blood samples, collected in central Portugal, 2021. All 35 positive sheep had attached positive R. sanguineus s.l., with matching nucleotidic sequences. These findings suggest that sheep may develop rickettsiemia and are likely capable of transmitting and amplifying the infection to uninfected ticks maintaining rickettsiae in circulation in the domestic cycle.


Assuntos
Rhipicephalus sanguineus , Infecções por Rickettsia , Rickettsia , Doenças dos Ovinos , Animais , Portugal , RNA Ribossômico 16S/genética , Rhipicephalus sanguineus/genética , Rhipicephalus sanguineus/microbiologia , Rickettsia/genética , Infecções por Rickettsia/epidemiologia , Infecções por Rickettsia/microbiologia , Infecções por Rickettsia/veterinária , Ovinos/genética , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/microbiologia
3.
Vet Parasitol Reg Stud Reports ; 32: 100743, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35725106

RESUMO

The cat flea (Ctenocephalides felis) is a competent vector of numerous bacterial pathogens in the genera Bartonella and Rickettsia. In the United States, free-roaming domestic cats (Felis catus) increase the risk of exposure to C. felis for humans and their companion animals. In collaboration with a trap-neuter-return program, we collected fleas from 283 feral/stray cats in southeastern Georgia between May and July of 2020. A total of 3,643 flea specimens were collected, and C. felis was the only flea species recovered from all cats sampled. The mean number of fleas per cat host was highest in the month of June when compared to May and July, and higher in juvenile cats (< 1 year) than the adults (≥ 1 year). Real-time PCR assays were used to test a subset of the collected fleas (n = 468) for the presence of Bartonella spp. and Rickettsia spp. DNA. Among those flea pools tested, 35.2% were positive for genus-specific citrate synthase gene of Bartonella, 16.5% were positive for the genus-specific 17-kDa protein antigen gene of Rickettsia, and none were positive for the species-specific outer membrane protein B gene of Rickettsia typhi. The identification of potential flea-borne pathogens was more frequent from the subset of C. felis collected in May, and female cats had more Bartonella-positive fleas and less Rickettsia-positive fleas than male cats. Overall, the present study provides valuable insights into the frequency of C. felis from outdoor community cats in southeastern Georgia, and highlights the possible risk for human exposure to potential flea-borne pathogens.


Assuntos
Bartonella , Doenças do Gato , Ctenocephalides , Infestações por Pulgas , Rickettsia , Sifonápteros , Animais , Bartonella/genética , Doenças do Gato/epidemiologia , Gatos , Chlamydia , Ctenocephalides/microbiologia , Feminino , Infestações por Pulgas/epidemiologia , Infestações por Pulgas/veterinária , Georgia/epidemiologia , Masculino , Rickettsia/genética
4.
Nat Commun ; 13(1): 3656, 2022 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-35760786

RESUMO

Rickettsia species of the spotted fever group are arthropod-borne obligate intracellular bacteria that can cause mild to severe human disease. These bacteria invade host cells, replicate in the cell cytosol, and spread from cell to cell. To access the host cytosol and avoid immune detection, they escape membrane-bound vacuoles by expressing factors that disrupt host membranes. Here, we show that a patatin-like phospholipase A2 enzyme (Pat1) facilitates Rickettsia parkeri infection by promoting escape from host membranes and cell-cell spread. Pat1 is important for infection in a mouse model and, at the cellular level, is crucial for efficiently escaping from single and double membrane-bound vacuoles into the host cytosol, and for avoiding host galectins that mark damaged membranes. Pat1 is also important for avoiding host polyubiquitin, preventing recruitment of autophagy receptor p62, and promoting actin-based motility and cell-cell spread.


Assuntos
Sistemas de Transporte de Aminoácidos/metabolismo , Infecções por Rickettsia , Rickettsia , Simportadores/metabolismo , Animais , Citosol/microbiologia , Camundongos , Fosfolipases/metabolismo , Rickettsia/genética , Rickettsia/metabolismo , Infecções por Rickettsia/microbiologia
6.
BMC Vet Res ; 18(1): 199, 2022 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-35624477

RESUMO

BACKGROUND: Rickettsia spp. are important tick-borne pathogens that cause various human and animal diseases worldwide. A tool for rapid and accurate detection of the pathogens from its vectors is necessary for prevention of Rickettsioses propagation in humans and animals, which are infested by ticks. Therefore, this study was conducted to evaluate a molecular tool, ultra-rapid real-time PCR (UR-qPCR), for rapid and accurate detection of Rickettsia spp. from 5644 ticks in 408 pools collected from livestock and their surrounding environments in Gangwon and Jeju province in South Korea. RESULTS: The UR-qPCR of Rickettsia DNA showed a limit of detection of 2.72 × 101 copies of Rickettsia DNA and no cross reaction with other tick-borne pathogens, namely Anaplasma phagocytophilum, Ehrlichia chaffeensis, E. canis, Toxoplasma gondii, and Borrelia burgdorferi. In addition, the PCR assay also showed possibility of various Rickettsia species detection including R. monacensis, "Candidatus R. longicornii", R. japonica, R. roultii, and R. tamurae. The collected ticks were identified with major species belonged to Haemaphysalis longicornis (81.62%), followed by H. flava (15.19%), and Ixodes nipponensis (3.19%). Rickettsia detection from tick samples using the UR-qPCR showed that the minimum infection rate (MIR) of Rickettsia in collected ticks was 1.24‰ and that all positive pools contained H. longicornis, equal to the MIR of 1.39‰ of this species. Additionally, MIR of Rickettsia spp. detected in ticks collected in Gangwon and Jeju was 1.53‰ and 0.84‰, respectively. Furthermore, the sequencing results of the 17 kDa protein antigen gene and ompA gene showed that Rickettsia spp. sequences from all pools were related to "Candidatus R. longicornii" and "Candidatus R. jingxinensis". CONCLUSIONS: The UR-qPCR system was demonstrated to be useful tool for accurate and rapid detection of Rickettsia from its vector, ixodid ticks, within 20 min. The data on Rickettsia spp. in ticks detected in this study provide useful information on the distribution of Rickettsia in previously unstudied Korean provinces, which are important for the prevention and control of the spread of rickettsioses in both animals and humans in the country.


Assuntos
Ixodes , Ixodidae , Infecções por Rickettsia , Rickettsia , Animais , Ixodes/microbiologia , Ixodidae/microbiologia , Prevalência , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Rickettsia/genética , Infecções por Rickettsia/epidemiologia , Infecções por Rickettsia/veterinária
7.
PLoS Negl Trop Dis ; 16(5): e0010437, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35576190

RESUMO

BACKGROUND: Rickettsia africae is a tick-borne bacterium that causes African tick-bite fever (ATBF) in humans. In southern Africa, the tick Amblyomma hebraeum serves as the primary vector and reservoir for R. africae and transmits the bacterium during any life stage. Previous research has shown that even when malaria has been dramatically reduced, unexplained acute febrile illnesses persist and may be explained by the serological evidence of rickettsiae in humans. METHODOLOGY/PRINCIPAL FINDINGS: We collected 12,711 questing Amblyomma larvae across multiple land use types in a savanna landscape in Eswatini. Our results show that host-seeking Amblyomma larvae are abundant across both space and time, with no significant difference in density by land use or season. We investigated the entomological risk (density of infected larvae) of ATBF from A. hebraeum larvae by testing over 1,600 individual larvae for the presence of R. africae using a novel multiplex qPCR assay. We found an infection prevalence of 64.9% (95% CI: 62.1-67.6%) with no land use type significantly impacting prevalence during the dry season of 2018. The mean density of infected larvae was 57.3 individuals per 100m2 (95% CI: 49-65 individuals per 100m2). CONCLUSIONS: Collectively, our results demonstrate R. africae infected A. hebraeum larvae, the most common tick species and life stage to bite humans in southern Africa, are ubiquitous in the savanna landscape of this region. Increased awareness of rickettsial diseases is warranted for policymakers, scientists, clinicians, and patients. Early detection of disease via increased clinician awareness and rapid diagnostics will improve patient outcomes for travelers and residents of this region.


Assuntos
Infecções por Rickettsia , Rickettsia , Rickettsiose do Grupo da Febre Maculosa , Doenças Transmitidas por Carrapatos , Carrapatos , Amblyomma , Animais , Essuatíni , Humanos , Rickettsia/genética , Infecções por Rickettsia/microbiologia , Doenças Transmitidas por Carrapatos/microbiologia , Carrapatos/microbiologia
8.
Nat Commun ; 13(1): 2630, 2022 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-35551207

RESUMO

Members of the bacterial genus Rickettsia were originally identified as causative agents of vector-borne diseases in mammals. However, many Rickettsia species are arthropod symbionts and close relatives of 'Candidatus Megaira', which are symbiotic associates of microeukaryotes. Here, we clarify the evolutionary relationships between these organisms by assembling 26 genomes of Rickettsia species from understudied groups, including the Torix group, and two genomes of 'Ca. Megaira' from various insects and microeukaryotes. Our analyses of the new genomes, in comparison with previously described ones, indicate that the accessory genome diversity and broad host range of Torix Rickettsia are comparable to those of all other Rickettsia combined. Therefore, the Torix clade may play unrecognized roles in invertebrate biology and physiology. We argue this clade should be given its own genus status, for which we propose the name 'Candidatus Tisiphia'.


Assuntos
Artrópodes , Rickettsia , Animais , Genômica , Mamíferos , Filogenia , Rickettsia/genética , Simbiose/genética
9.
Trop Biomed ; 39(1): 55-59, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35507925

RESUMO

Ticks are important vectors of arthropod-borne diseases and they can transmit a wide variety of zoonotic pathogens to humans, domestic and wild animals. Rickettsia japonica is a member of SFG rickettsiae causing Japanese spotted fever (JSF) and can transmit to humans via infected ticks. In this study, we report the first case of Rickettsia japonica in Haemaphysalis hystricis tick collected from a roadkill Burmese ferret-badger ( Melogale personata ) in Loei province, northeastern Thailand. According to the DNA sequences and phylogenetic analyses of the outer membrane protein A and B genes ( ompA and ompB), the detected R. japonica was identical to those found in JSF patients in Korea, Japan, and China, and closely related to Rickettsia detected by ompA in a tick from Thailand. Further study on the prevalence of R. japonica and diversity of mammalian reservoir hosts will be useful to gain a better understanding of JSF epidemiology.


Assuntos
Ixodidae , Mustelidae , Rickettsia , Carrapatos , Animais , Furões , Humanos , Ixodidae/microbiologia , Filogenia , Rickettsia/genética , Tailândia , Carrapatos/microbiologia
10.
Parasit Vectors ; 15(1): 162, 2022 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-35526060

RESUMO

BACKGROUND: The raccoon Procyon lotor (Linnaeus, 1758) (Carnivora; Procyonidae) is one of the most important and most intensively studied invasive mammal species in Europe. Within the last 30 years the raccoon has spread at an increasing rate, resulting in the establishment of local populations in various regions of Europe. In these newly colonised areas, gaps in knowledge of the raccoon's biology concern not only most aspects of its ecology in a broad sense, but also its pathogens and parasites. Most micropathogens recorded hitherto in the raccoons that have colonised Europe have documented epizootic and zoonotic potential. Thus, it is considered especially important to investigate the role played by the raccoon in the spread of pathogens through both animal-animal and animal-human pathways. METHODS: Tissue samples of raccoons from Poland and Germany were examined in this study. In total, 384 tissue samples from 220 raccoons (170 spleen samples, 82 liver biopsies, 132 ear biopsies) were examined using molecular methods. The presence of Rickettsia spp. DNA was screened through amplification of a fragment of the gltA gene. Samples that were PCR positive for gltA were tested for other rickettsial genes, ompB and a 17-kDa antigen. For taxonomic purposes, the obtained sequences were compared with corresponding sequences deposited in GenBank using the Basic Local Alignment Search Tool, and phylogenetic analyses were conducted using Bayesian inference implemented in MrBayes software. RESULTS: Rickettsia DNA was confirmed only in skin biopsies; no isolates from the spleen or liver were positive for Rickettsia DNA. With the exception of one sample from Germany, which was positive for Rickettsia helvetica DNA, all the samples positive for Rickettsia DNA derived from the Polish population of raccoons. DNA of Rickettsia spp. was detected in 25 samples, i.e. 11.4% of the tested raccoons, and R. helvetica was confirmed in 52% of the positive samples. Additionally, single cases of Rickettsia monacensis, Rickettsia raoultii, and Candidatus Rickettsia kotlanii-like were found, and in 32% of all the positive samples similarity was shown to different Rickettsia endosymbionts. Out of the samples that tested positive for gltA, amplicons of ompB and 17 kDa were successfully sequenced from 14 and three samples, respectively. CONCLUSIONS: To the best of our knowledge, this study provides, for the first time, evidence of the occurrence of Rickettsia pathogens and endosymbionts in the European population of raccoons. Further, broader research on different species of wild vertebrates, and ticks, as potential vectors and hosts for tick-borne pathogens, in natural as well as in peri-urban environments, is therefore required.


Assuntos
Rickettsia , Rickettsiose do Grupo da Febre Maculosa , Carrapatos , Animais , Teorema de Bayes , Filogenia , Guaxinins
11.
Front Cell Infect Microbiol ; 12: 880813, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35592653

RESUMO

Background: The genus Rickettsia (Alphaproteobacteria: Rickettsiales) encompasses numerous obligate intracellular species with predominantly ciliate and arthropod hosts. Notable species are pathogens transmitted to mammals by blood-feeding arthropods. Mammalian pathogenicity evolved from basal, non-pathogenic host-associations; however, some non-pathogens are closely related to pathogens. One such species, Rickettsia buchneri, is prevalent in the blacklegged tick, Ixodes scapularis. While I. scapularis transmits several pathogens to humans, it does not transmit Rickettsia pathogens. We hypothesize that R. buchneri established a mutualism with I. scapularis, blocking tick superinfection with Rickettsia pathogens. Methods: To improve estimates for assessing R. buchneri infection frequency in blacklegged tick populations, we used comparative genomics to identify an R. buchneri gene (REIS_1424) not present in other Rickettsia species present throughout the I. scapularis geographic range. Bioinformatic and phylogenomics approaches were employed to propose a function for the hypothetical protein (263 aa) encoded by REIS_1424. Results: REIS_1424 has few analogs in other Rickettsiales genomes and greatest similarity to non-Proteobacteria proteins. This cohort of proteins varies greatly in size and domain composition, possessing characteristics of Recombination hotspot (Rhs) and contact dependent growth inhibition (CDI) toxins, with similarity limited to proximal C-termini (~145 aa). This domain was named CDI-like/Rhs-like C-terminal toxin (CRCT). As such proteins are often found as toxin-antidote (TA) modules, we interrogated REIS_1423 (151 aa) as a putative antidote. Indeed, REIS_1423 is similar to proteins encoded upstream of CRCT domain-containing proteins. Accordingly, we named these proteins CDI-like/Rhs-like C-terminal toxin antidotes (CRCA). R. buchneri expressed both REIS_1423 and REIS_1424 in tick cell culture, and PCR assays showed specificity for R. buchneri over other rickettsiae and utility for positive detection in three tick populations. Finally, phylogenomics analyses uncovered divergent CRCT/CRCA modules in varying states of conservation; however, only R. buchneri and related Tamurae/Ixodes Group rickettsiae carry complete TA modules. Conclusion: We hypothesize that Rickettsia CRCT/CRCA modules circulate in the Rickettsia mobile gene pool, arming rickettsiae for battle over arthropod colonization. While its functional significance remains to be tested, R. buchneri CRCT/CRCA serves as a marker to positively identify infection and begin deciphering the role this endosymbiont plays in the biology of the blacklegged tick.


Assuntos
Ixodes , Rickettsia , Animais , Antídotos , Humanos , Ixodes/microbiologia , Mamíferos , Filogenia , Rickettsia/genética , Simbiose
12.
PLoS Negl Trop Dis ; 16(5): e0010354, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35639778

RESUMO

Murine typhus, which is caused by Rickettsia typhi, has a wide range of clinical manifestations. It has a low mortality rate but may result in meningoencephalitis and interstitial pneumonia in severe cases. Comparisons of complete genome sequences of R. typhi isolates from North Carolina, USA (Wilmington), Myanmar (B9991PP), and Thailand (TH1527) identified only 26 single nucleotide polymorphism (SNP) and 7 insertion-deletion (INDEL) sites in these highly syntenic genomes. Assays were developed to further define the distribution of these variant sites among 15 additional isolates of R. typhi with different histories from Asia, the USA, and Africa. Mismatch amplification mutation assays (MAMA) were validated for 22 SNP sites, while the 7 INDEL sites were analyzed directly on agarose gels. Six SNP types, 9 INDEL types, 11 total types were identified among these 18 isolates. Replicate DNA samples as well as comparisons of isolates with different passage and source histories gave consistent genetic typing profiles. Comparison of the SNP and INDEL markers to R. typhi's nearest neighbor Rickettsia prowazekii demonstrated that the majority of the SNPs represent intra-species variation that arose post divergence of these two species while several INDEL sites also exhibited intraspecies variability among the R. prowazekii genomes that have been completely sequenced. The assays for the presence of these SNP and INDEL sites, particularly the latter, comprise a low technology gel method for consistently distinguishing R. typhi and R. prowazekii as well as for differentiating genetic types of R. typhi.


Assuntos
Rickettsia prowazekii , Rickettsia , Tifo Endêmico Transmitido por Pulgas , Animais , Camundongos , Rickettsia/genética , Rickettsia prowazekii/genética , Rickettsia typhi/genética , Análise de Sequência de DNA , Tailândia
13.
Ticks Tick Borne Dis ; 13(4): 101961, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35490548

RESUMO

The occurrence of tick-borne pathogens (TBPs) of human and veterinary interest was studied in questing and feeding ticks collected from wild animals in a region in North-Western Spain. A total of 529 ticks (489 questing, 40 feeding) of seven different species (386 Ixodes ricinus, 53 Haemaphysalis concinna, 27 Haemaphysalis punctata, 25 Dermacentor marginatus, 21 Haemaphysalis inermis, 15 Dermacentor reticulatus, and two Rhipicephalus bursa) were analyzed. Molecular analysis of the 16S rRNA gene in I. ricinus ticks, revealed the presence of two phylogenetic groups in the region. Most of the sequenced ticks (96%) were assigned to I. ricinus haplogroup and 4% of the ticks were phylogenetically related to I. inopinatus haplogroup. Feeding ticks were removed from 17 animals from seven wild species (seven roe deer -Capreolus capreolus-, three wolves -Canis lupus-, two Iberian red deer -Cervus elaphus hispanicus-, two European wild boar -Sus scrofa-, one Cantabrian brown bear -Ursus arctos-, one Eurasian badger -Meles meles-, and one red fox -Vulpes vulpes-). Presence of Rickettsia spp., Anaplasma phagocytophilum, piroplasms, Borrelia burgdorferi sensu lato (s.l.) and Coxiella burnetii were tested in ticks by specific PCR. A total of 92 (17.4%) of the 529 ticks analyzed were positive for at least one of the TBPs tested. Sequencing revealed the presence of the genospecies "Candidatus Rickettsia rioja", Rickettsia raoultii, and Anaplasma phagocytophilum in both questing and feeding ticks. Rickettsia slovaca, Borrelia lusitaniae, Borrelia afzelii, Borrelia garinii, Borrelia burgdorferi sensu stricto and Babesia bigemina were only detected in questing ticks, while Babesia sp. badger type A, Theileria OT3 and Hepatozoon canis occurred only in engorged ticks. None of the ticks were positive for C. burnetii. The analysis of the 16S rRNA gene sequences of A. phagocytophilum revealed the presence of three variants (I, X and W) circulating in the region. New host-tick-pathogen interactions have been revealed, finding for the first time the human pathogen R. raoultii in D. reticulatus removed from a Cantabrian brown bear. Co-occurrence between different TBPs were detected in 4.3% of the ticks. The association B. burgdorferi s.l./Rickettsia spp. was detected in questing ticks; and Rickettsia spp./piroplasms and A. phagocytophilum/Theileria OT3 in feeding ticks. The presence of pathogenic agents constitutes a threat to human and animal health, and should be considered in the diagnosis and treatment after a tick bite. This study increases the knowledge on TBPs diversity of medical and veterinary interest circulating between ticks and their hosts in North-Western Spain.


Assuntos
Anaplasma phagocytophilum , Babesia , Grupo Borrelia Burgdorferi , Borrelia burgdorferi , Borrelia , Coxiella burnetii , Cervos , Ixodes , Ixodidae , Rickettsia , Anaplasma phagocytophilum/genética , Animais , Babesia/genética , Borrelia/genética , Borrelia burgdorferi/genética , Grupo Borrelia Burgdorferi/genética , Coxiella burnetii/genética , Ixodes/microbiologia , Ixodidae/genética , Filogenia , RNA Ribossômico 16S/genética , Rickettsia/genética , Espanha/epidemiologia
14.
Ticks Tick Borne Dis ; 13(4): 101959, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35490549

RESUMO

In the south-central United States, several tick-borne diseases (TbDs) occur at or near their highest levels of incidence of anywhere in the U.S. The diversity of Rickettsia species found in Amblyomma americanum continues to be under-characterized in this region and throughout the U.S. and Canada where this tick species is expanding. One reason for this lack of knowledge about Rickettsia diversity is the high prevalence of the endosymbiont Rickettsia amblyommatis that obscures detection of other bacteria in this genus. Focusing on unknown rickettsial agents, we used a recently described R. amblyommatis exclusion assay to screen 1909 A. americanum collected in Oklahoma City, Oklahoma, which resulted in eight ticks that had unique rickettsial sequences. Through the process of characterizing primary and secondary rickettsiae, we identified ticks primarily infected with Rickettsia rhipicephali and a Rickettsia species (2019-CO-FNY) previously linked with a canine rickettsiosis case in Tulsa, Oklahoma. We also identified a Rickettsia agent that was 97% identical with an endosymbiont of Amblyomma tonelliae and which aligned with archaic rickettsial species. Through this study, we further demonstrate the usefulness of this exclusion assay for rapid screening in large cohort A. americanum studies to identify a small number of ticks that contain poorly described and previously undocumented rickettsiae.


Assuntos
Ixodidae , Rickettsia , Carrapatos , Amblyomma , Animais , Canadá , Cães , Humanos , Ixodidae/microbiologia , Oklahoma/epidemiologia
15.
Ticks Tick Borne Dis ; 13(4): 101960, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35537238

RESUMO

African tick bite fever (ATBF) is one of the most important rickettsial infections in international travellers to sub-Saharan Africa. The heterogeneity of Rickettsia africae infection rates among tick vector species has been studied. However, this information has not been systematised to allow for comparative estimates. Quantifying the trends and heterogeneity in R. africae infection rates among the different tick vector species is paramount in understanding the role in transmission to humans. A systematic search was conducted in PubMed, Web of Knowledge, Google Scholar, and SCOPUS from 2005 to 2020. The selection criteria included all studies in sub-Saharan Africa reporting R. africae infection rates in tick adults, nymphs, and larvae. A quality effects model was used in the meta-analysis due to the observed heterogeneity with an assessment of publication bias using funnel plots. The prevalence estimates were conducted by geographic region and tick genus from 32 studies reporting R. africae infection rates in ticks from sub-Saharan Africa. A total of 12,301 ticks comprising of adults (96.19%, n=11, 832), nymphs (3.6%, n=443) and larvae (0.2%, n=26) and 1214 pooled samples were evaluated for R. africae infection. The overall prevalence of R. africae was higher in Amblyomma spp. (48%, 95% CI: 26-70%) compared to Rhipicephalus spp. (1%, 95% CI: 0-5%), Hyalomma spp. (1%, 95% CI: 0-3%) and other tick genera (1%, 95% CI: 0-4%) throughout all regions. The highest prevalence in Amblyomma spp. was recorded in western Africa (53%, 95% CI: 14-90%) and in Rhipicephalus spp. in southern Africa (2%, 95% CI: 0-5%). Cattle were the most frequently sampled hosts across all tick vectors (62.98%, n=5492), followed by goats (19.07%, n= 1663) and sheep (9.1%, n= 793). To our knowledge, this is the first systematic and quantitative analysis of R. africae infection in tick vectors collected from mammalian hosts in sub-Saharan Africa. The results highlight a marked heterogeneity between species in different regions of sub-Saharan Africa and provide initial estimates of infection rates.


Assuntos
Rhipicephalus , Rickettsia , Rickettsiose do Grupo da Febre Maculosa , África ao Sul do Saara/epidemiologia , Amblyomma , Animais , Bovinos , Mamíferos , Ninfa , Prevalência , Ovinos
16.
Infect Genet Evol ; 102: 105291, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35490957

RESUMO

Rickettsial diseases have seen a re-emergence in the Americas in the last few decades, with concerning morbidity, mortality and economic implications that result from loss of productivity, income, curbs in liberal trade agreements, and reduction in agricultural practices. The aim of this study is to determine the socioecological determinants and seroprevalence for Rickettsia typhi and Rickettsia rickettsii among residents of Teabo, a rural community of Yucatán, Mexico. Sociodemographic data and serum samples were obtained from 180 consenting participants. Antibody titers for R. typhi and R. rickettsii were determined by indirect immunofluorescence assay (IFA). Participants also submitted tick samples collected from their residential area. We conducted logistic regression models to evaluate the association between exposure variables and seroprevalence. Rhipicephalus sanguineus s.l. (37%; n = 65), and Amblyomma cajennense Fabricius (17%; n = 29) were the predominant tick species in peri-domestic areas. Out of the 180 participants, there was significantly higher seroprevalence of R. typhi (n = 77; 46%) compared to R. rickettsii [n = 27, 15%, (p < 0.05)]. Pearson's chi-square test of independence revealed significant differences in R. rickettsii seroprevalence by gender (X2 [n = 175, df = 4, (p < 0.001)] = 180.26), level of education, (X2 [n = 180, df = 4, (p < 0.001)] = 44.0), and by tick species found in residential area, (X2 [n = 180, df = 4, (p = 0.050)] = 9.48). After adjusting for other variables in a logistic regression model, for each unit increase in the number of dogs present in the residential area, there was a 27% increase in the odds of human seroprevalence for R. typhi IgG (AOR = 1.27, 95% CI: 1.01-1.63). Compared to study participants living in residential areas with a 'low' height of vegetation, those living in residential areas with a 'medium' height of vegetation had 2.5 times greater odds of human seroprevalence for R. typhi IgG (AOR = 2.51, 95% CI: 1.19-5.40). Potentially modifiable existing factors in the peri-domestic area may constitute a high-risk source of seroprevalence for rickettsial antibodies among residents of the rural community of Teabo, Yucatán, Mexico.


Assuntos
Doenças do Cão , Rhipicephalus sanguineus , Rickettsia , Animais , Doenças do Cão/microbiologia , Cães , Humanos , Imunoglobulina G , México/epidemiologia , Rhipicephalus sanguineus/microbiologia , População Rural , Estudos Soroepidemiológicos
17.
Artigo em Inglês | MEDLINE | ID: mdl-35627785

RESUMO

Of the documented tick-borne diseases infecting humans in México, Rocky Mountain spotted fever (RMSF), caused by the Gram-negative bacterium Rickettsia rickettsii, is responsible for most fatalities. Given recent evidence of brown dog tick, Rhipicephalus sanguineus s.l., as an emerging vector of human RMSF, we aimed to evaluate dogs and their ticks for rickettsiae infections as an initial step in assessing the establishment of this pathosystem in a poorly studied region of northeastern México while evaluating the use of dogs as sentinels for transmission/human disease risk. We sampled owned dogs living in six disadvantaged neighborhoods of Reynosa, northeastern México to collect whole blood and ticks. Of 168 dogs assessed, tick infestation prevalence was 53%, composed of exclusively Rh. sanguineus s. l. (n = 2170 ticks). Using PCR and sequencing, we identified an overall rickettsiae infection prevalence of 4.1% (n = 12/292) in ticks, in which eight dogs harbored at least one infected tick. Rickettsiae infections included Rickettsia amblyommatis and Rickettsia parkeri, both of which are emerging human pathogens, as well as Candidatus Rickettsia andeanae. This is the first documentation of pathogenic Rickettsia species in Rh. sanguineus s.l. collected from dogs from northeastern México. Domestic dog infestation with Rickettsia-infected ticks indicates ongoing transmission; thus, humans are at risk for exposure, and this underscores the importance of public and veterinary health surveillance for these pathogens.


Assuntos
Doenças do Cão , Rhipicephalus sanguineus , Rickettsia , Infestações por Carrapato , Animais , Doenças do Cão/epidemiologia , Cães , Humanos , México/epidemiologia , Rhipicephalus sanguineus/microbiologia , Rickettsia/genética , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/veterinária
18.
PLoS One ; 17(5): e0268172, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35587930

RESUMO

Ticks are one of the most important vectors of several pathogens affecting humans and animals. In addition to pathogens, ticks carry diverse microbiota of symbiotic and commensal microorganisms. In this study, we have investigated the first Tunisian insight into the microbial composition of the most dominant Hyalomma species infesting Tunisian cattle and explored the relative contribution of tick sex, life stage, and species to the diversity, richness and bacterial species of tick microbiome. In this regard, next generation sequencing for the 16S rRNA (V3-V4 region) of tick bacterial microbiota and metagenomic analysis were established. The analysis of the bacterial diversity reveals that H. marginatum and H. excavatum have greater diversity than H. scupense. Furthermore, microbial diversity and composition vary according to the tick's life stage and sex in the specific case of H. scupense. The endosymbionts Francisella, Midichloria mitochondrii, and Rickettsia were shown to be the most prevalent in Hyalomma spp. Rickettsia, Francisella, Ehrlichia, and Erwinia are the most common zoonotic bacteria found in Hyalomma ticks. Accordingly, Hyalomma ticks could represent potential vectors for these zoonotic bacterial agents.


Assuntos
Francisella , Ixodidae , Microbiota , Rickettsia , Carrapatos , Animais , Bovinos , Francisella/genética , Sequenciamento de Nucleotídeos em Larga Escala , Ixodidae/genética , Ixodidae/microbiologia , Microbiota/genética , RNA Ribossômico 16S/genética , Rickettsia/genética , Carrapatos/genética
20.
Anal Bioanal Chem ; 414(13): 3791-3802, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35416505

RESUMO

The black-legged tick, Ixodes scapularis, is a well-known vector for the Lyme disease-causing pathogen (Borrelia burgdorferi) but can also carry other disease-causing pathogens such as Rickettsia, Anaplasma, Bartonella, Ehrlichia, and Theileria. Hence, tick screening using highly specific protein signatures for specific pathogens will help assess the prevalence of infected ticks and understand the pathogen-tick interactions in a specific geographic area. In this study, we used data-dependent acquisition to key pathogen protein signatures in black-legged ticks collected from the Southern Tier New York. Bottom-up proteomic analysis of extract from five combined ticks identified 2,052 tick proteins and 41 pathogen proteins with high confidence (≥ 99% C.I.). Results show high peptide spectral match counts for Rickettsia species and Borrelia species and lower counts for other rarer pathogens such as Anaplasma phagocytophilum. Parallel reaction monitoring performed on protein extracts from individual ticks (n = 10) revealed that 8 out of the 10 screened ticks carried Rickettsia species, 5 carried Borrelia species, 3 carried both pathogens, and only 1 tick carried no detectable bacteria. Mass spectrometry-based proteomics is a highly specific way to define the expression of different types of pathogen proteins in infected ticks. This might bring insights into the tick-pathogen interactions at the molecular level and especially expression pathogen surface proteins in ticks.


Assuntos
Borrelia , Ixodes , Rickettsia , Animais , Ixodes/microbiologia , Espectrometria de Massas , Proteômica
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