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Open Forum Infectious Diseases Jul 2021We present 10 patients with infection in whom next-generation sequencing of microbial cell-free deoxyribonucleic acid (mcfDNA) was used as a diagnostic tool. mcfDNA...
We present 10 patients with infection in whom next-generation sequencing of microbial cell-free deoxyribonucleic acid (mcfDNA) was used as a diagnostic tool. mcfDNA was detected in all cases and was more rapid and specific than rickettsial serology. mcfDNA impacted antibiotic management in 50% of patients.
PubMed: 34250186
DOI: 10.1093/ofid/ofab147 -
Socio-ecological determinants of rickettsial seroprevalence in a rural community of Yucatán, Mexico.Infection, Genetics and Evolution :... Aug 2022Rickettsial diseases have seen a re-emergence in the Americas in the last few decades, with concerning morbidity, mortality and economic implications that result from...
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 (X [n = 175, df = 4, (p < 0.001)] = 180.26), level of education, (X [n = 180, df = 4, (p < 0.001)] = 44.0), and by tick species found in residential area, (X [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.
Topics: Animals; Dog Diseases; Dogs; Humans; Immunoglobulin G; Mexico; Rhipicephalus sanguineus; Rickettsia; Rural Population; Seroepidemiologic Studies
PubMed: 35490957
DOI: 10.1016/j.meegid.2022.105291 -
Clinical Infectious Diseases : An... Apr 2019This study examined the literature on laboratory-acquired infections (LAIs) associated with scrub typhus (Orientia tsutsugamushi) and murine typhus (Rickettsia typhi)... (Review)
Review
Laboratory-acquired Scrub Typhus and Murine Typhus Infections: The Argument for a Risk-based Approach to Biosafety Requirements for Orientia tsutsugamushi and Rickettsia typhi Laboratory Activities.
This study examined the literature on laboratory-acquired infections (LAIs) associated with scrub typhus (Orientia tsutsugamushi) and murine typhus (Rickettsia typhi) research to provide an evidence base for biosafety and biocontainment. Scrub typhus LAIs were documented in 25 individuals, from 1931 to 2000 with 8 (32%) deaths during the preantibiotic era. There were 35 murine typhus LAI reports and no deaths. Results indicated that the highest-risk activities were working with infectious laboratory animals involving significant aerosol exposures, accidental self-inoculation, or bite-related infections. A risk-based biosafety approach for in vitro and in vivo culture of O. tsutsugamushi and R. typhi would require that only high-risk activities (animal work or large culture volumes) be performed in high-containment biosafety level (BSL) 3 laboratories. We argue that relatively low-risk activities including inoculation of cell cultures or the early stages of in vitro growth using low volumes/low concentrations of infectious materials can be performed safely in BSL-2 laboratories within a biological safety cabinet.
Topics: Containment of Biohazards; Humans; Laboratory Infection; Orientia tsutsugamushi; Rickettsia typhi; Risk Assessment; Safety Management; Scrub Typhus; Typhus, Endemic Flea-Borne
PubMed: 30107504
DOI: 10.1093/cid/ciy675 -
Revista Do Instituto de Medicina... 2015Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and...
Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study's results contributed to a better knowledge of Rickettsia epidemiology in Yucatán.
Topics: Animals; Disease Vectors; Humans; Mexico; Muridae; Parasites; Polymerase Chain Reaction; Rickettsia felis; Rickettsia typhi; Rodentia; Siphonaptera; Typhus, Endemic Flea-Borne
PubMed: 25923891
DOI: 10.1590/S0036-46652015000200005 -
Vector Borne and Zoonotic Diseases... Feb 2020Murine typhus is a tropical disease caused and is endemic in resource-limited settings such as Southeast Asian countries. Early diagnosis of infection facilitates...
Murine typhus is a tropical disease caused and is endemic in resource-limited settings such as Southeast Asian countries. Early diagnosis of infection facilitates appropriate management and reduces the risk of severe disease. However, molecular detection of in blood is insensitive due to low rickettsemia. Furthermore, the gold standard of sero-diagnosis by immunofluorescence assay (IFA) is cumbersome, subjective, impractical, and unavailable in many endemic areas. In an attempt to identify a practical diagnostic approach that can be applied in Indonesia, we evaluated the performance of commercial IgM and IgG enzyme-linked immunosorbent assay (ELISA) and IFA using paired plasma from previously studied PCR-positive cases and controls with other known infections. Sensitivity and specificity of combined ELISA IgM and IgG anti- using paired specimens were excellent (95.0% and 98.3%, respectively), comparable to combined IFA IgM and IgG (97.5% and 100%, respectively); sensitivity of ELISA IgM from acute specimens only was poor (45.0%), but specificity was excellent (98.3%). IFA IgM was more sensitive (77.5%), but less specific (89.7%) for single specimens.
Topics: Antibodies, Bacterial; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Humans; Immunoglobulin G; Immunoglobulin M; Indonesia; Rickettsia typhi; Sensitivity and Specificity; Typhus, Endemic Flea-Borne
PubMed: 31448989
DOI: 10.1089/vbz.2019.2451 -
Tropical Medicine and Infectious Disease Jan 2018Mosquito-borne diseases are common high-impact diseases in tropical and subtropical areas. However, other non-mosquito vector-borne pathogens (VBPs) may share their... (Review)
Review
Mosquito-borne diseases are common high-impact diseases in tropical and subtropical areas. However, other non-mosquito vector-borne pathogens (VBPs) may share their geographic distribution, seasonality, and clinical manifestations, thereby contributing their share to the morbidity and mortality caused by febrile illnesses in these regions. The purpose of this work was to collect and review existing information and identify knowledge gaps about tick, flea-, and louse-borne diseases of veterinary and public health significance in Nigeria. Full-length articles about VBPs were reviewed and relevant information about the vectors, their hosts, geographic distribution, seasonality, and association(s) with human or veterinary diseases was extracted. Specific laboratory tools used for detection and identification of VBPs in Nigeria were also identified. A total of 62 original publications were examined. Substantial information about the prevalence and impacts of ticks and fleas on pet and service dogs (18 articles), and livestock animals (23 articles) were available; however, information about their association with and potential for causing human illnesses was largely absent despite the zoonotic nature of many of these peri-domestic veterinary diseases. Recent publications that employed molecular methods of detection demonstrated the occurrence of several classic (, , sp.) and emerging human pathogens (, ) in ticks and fleas. However, information about other pathogens often found in association with ticks () and fleas (, ) across the African continent was lacking. Records of louse-borne epidemic typhus in Nigeria date to 1947; however, its current status is not known. This review provides an essential baseline summary of the current knowledge in Nigeria of non-mosquito VBPs, and should stimulate improvements in the surveillance of the veterinary and human diseases they cause in Nigeria. Due to increasing recognition of these diseases in other African countries, veterinary and public health professionals in Nigeria should expand the list of possible diseases considered in patients presenting with fever of unknown etiology.
PubMed: 30274402
DOI: 10.3390/tropicalmed3010003 -
The American Journal of Tropical... Jan 2024
Topics: Animals; Humans; Siphonaptera; Rickettsia typhi; Typhus, Endemic Flea-Borne; Rickettsia Infections; California; Rickettsia; Rickettsia felis
PubMed: 38109770
DOI: 10.4269/ajtmh.23-0742 -
Frontiers in Cellular and Infection... 2022Rickettsia is a genus of nonmotile, Gram-negative, non-spore-forming, highly pleomorphic bacteria that cause severe epidemic rickettsioses. The spotted fever group and... (Review)
Review
Rickettsia is a genus of nonmotile, Gram-negative, non-spore-forming, highly pleomorphic bacteria that cause severe epidemic rickettsioses. The spotted fever group and typhi group are major members of the genus Rickettsia. Rickettsial species from the two groups subvert diverse host cellular processes, including membrane dynamics, actin cytoskeleton dynamics, phosphoinositide metabolism, intracellular trafficking, and immune defense, to promote their host colonization and intercellular transmission through secreted effectors (virulence factors). However, lineage-specific rickettsiae have exploited divergent strategies to accomplish such challenging tasks and these elaborated strategies focus on distinct host cell processes. In the present review, we summarized current understandings of how different rickettsial species employ their effectors' arsenal to affect host cellular processes in order to promote their own replication or to avoid destruction.
Topics: Humans; Rickettsia; Rickettsia Infections; Signal Transduction
PubMed: 36389139
DOI: 10.3389/fcimb.2022.995933 -
PLoS Neglected Tropical Diseases Oct 2014Little is known about the presence/absence and prevalence of Rickettsia spp, Bartonella spp. and Yersinia pestis in domestic and urban flea populations in tropical and...
UNLABELLED
Little is known about the presence/absence and prevalence of Rickettsia spp, Bartonella spp. and Yersinia pestis in domestic and urban flea populations in tropical and subtropical African countries.
METHODOLOGY/PRINCIPAL FINDINGS
Fleas collected in Benin, the United Republic of Tanzania and the Democratic Republic of the Congo were investigated for the presence and identity of Rickettsia spp., Bartonella spp. and Yersinia pestis using two qPCR systems or qPCR and standard PCR. In Xenopsylla cheopis fleas collected from Cotonou (Benin), Rickettsia typhi was detected in 1% (2/199), and an uncultured Bartonella sp. was detected in 34.7% (69/199). In the Lushoto district (United Republic of Tanzania), R. typhi DNA was detected in 10% (2/20) of Xenopsylla brasiliensis, and Rickettsia felis was detected in 65% (13/20) of Ctenocephalides felis strongylus, 71.4% (5/7) of Ctenocephalides canis and 25% (5/20) of Ctenophthalmus calceatus calceatus. In the Democratic Republic of the Congo, R. felis was detected in 56.5% (13/23) of Ct. f. felis from Kinshasa, in 26.3% (10/38) of Ct. f. felis and 9% (1/11) of Leptopsylla aethiopica aethiopica from Ituri district and in 19.2% (5/26) of Ct. f. strongylus and 4.7% (1/21) of Echidnophaga gallinacea. Bartonella sp. was also detected in 36.3% (4/11) of L. a. aethiopica. Finally, in Ituri, Y. pestis DNA was detected in 3.8% (1/26) of Ct. f. strongylus and 10% (3/30) of Pulex irritans from the villages of Wanyale and Zaa.
CONCLUSION
Most flea-borne infections are neglected diseases which should be monitored systematically in domestic rural and urban human populations to assess their epidemiological and clinical relevance. Finally, the presence of Y. pestis DNA in fleas captured in households was unexpected and raises a series of questions regarding the role of free fleas in the transmission of plague in rural Africa, especially in remote areas where the flea density in houses is high.
Topics: Africa; Animals; Bartonella; DNA, Bacterial; Humans; Molecular Sequence Data; Rickettsia felis; Rickettsia typhi; Siphonaptera; Yersinia pestis
PubMed: 25299702
DOI: 10.1371/journal.pntd.0003152 -
International Journal of Infectious... Jul 2011The aim of this work was to evaluate the prevalence of past infection due to Rickettsia typhi and Rickettsia conorii in the Canary Islands (Spain).
OBJECTIVE
The aim of this work was to evaluate the prevalence of past infection due to Rickettsia typhi and Rickettsia conorii in the Canary Islands (Spain).
METHODS
A representative sample of the population of the seven islands, formed of 662 people aged between 5 and 75 years (368 females, 294 males), was analyzed. Epidemiological data were obtained by direct survey. The detection of serum IgG antibodies against both microorganisms was based on an indirect immunofluorescence test, considered positive if the titers were ≥ 1/80.
RESULTS
Of the analyzed population 3.9% had IgG antibodies against R. typhi and 4.4% against R. conorii. Out of these positive samples, only three were positive for both species. The seroprevalence was similar in both sexes. Positive results were found in all age groups, but a higher rate was noticed in those aged 46 years and older (p<0.05). R. typhi was found to be more prevalent in rural areas of all islands, as well as in farmers.
CONCLUSIONS
Our results confirm the presence of antibodies against the causative agents of murine typhus and Mediterranean spotted fever in the Canary Islands. Indirect data suggest that the detection of antibodies to R. conorii might be due to a cross-reaction between these species.
Topics: Adolescent; Adult; Aged; Antibodies, Bacterial; Boutonneuse Fever; Child; Child, Preschool; Female; Humans; Immunoglobulin G; Male; Middle Aged; Rickettsia conorii; Rickettsia typhi; Seroepidemiologic Studies; Spain; Typhus, Endemic Flea-Borne; Young Adult
PubMed: 21612963
DOI: 10.1016/j.ijid.2011.03.019