RESUMEN
Human inborn errors of IFN-γ immunity underlie mycobacterial diseases. We describe patients with Mycobacterium bovis (BCG) disease who are homozygous for loss-of-function mutations of SPPL2A. This gene encodes a transmembrane protease that degrades the N-terminal fragment (NTF) of CD74 (HLA invariant chain) in antigen-presenting cells. The CD74 NTF therefore accumulates in the HLA class II+ myeloid and lymphoid cells of SPPL2a-deficient patients. This toxic fragment selectively depletes IL-12- and IL-23-producing CD1c+ conventional dendritic cells (cDC2s) and their circulating progenitors. Moreover, SPPL2a-deficient memory TH1* cells selectively fail to produce IFN-γ when stimulated with mycobacterial antigens in vitro. Finally, Sppl2a-/- mice lack cDC2s, have CD4+ T cells that produce small amounts of IFN-γ after BCG infection, and are highly susceptible to infection with BCG or Mycobacterium tuberculosis. These findings suggest that inherited SPPL2a deficiency in humans underlies mycobacterial disease by decreasing the numbers of cDC2s and impairing IFN-γ production by mycobacterium-specific memory TH1* cells.
Asunto(s)
Ácido Aspártico Endopeptidasas/genética , Ácido Aspártico Endopeptidasas/metabolismo , Células Dendríticas/inmunología , Proteínas de la Membrana/metabolismo , Infecciones por Mycobacterium/inmunología , Mycobacterium bovis/fisiología , Mycobacterium tuberculosis/fisiología , Células TH1/inmunología , Tuberculosis/inmunología , Animales , Antígenos de Diferenciación de Linfocitos B/metabolismo , Células Cultivadas , Antígenos HLA/metabolismo , Antígenos de Histocompatibilidad Clase II/metabolismo , Humanos , Inmunidad , Memoria Inmunológica , Lactante , Interferón gamma/metabolismo , Linfadenopatía , Masculino , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mutación/genética , Infecciones por Mycobacterium/genética , VacunaciónRESUMEN
The exposure of a research team to chigger mites in southern Chile allowed the first identification of a trombiculid species as vector and reservoir of scrub typhus outside the tsutsugamushi triangle, providing unique insights into the ecology and transmission of this recently discovered rickettsial infection in South America.
Asunto(s)
Orientia tsutsugamushi , Tifus por Ácaros , Trombiculidae , Animales , Regiones Antárticas , Chile/epidemiología , Humanos , Tifus por Ácaros/epidemiologíaRESUMEN
BACKGROUND: The development of effective vaccines against coronavirus disease 2019 is a global priority. CoronaVac is an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine with promising safety and immunogenicity profiles. This article reports safety and immunogenicity results obtained for healthy Chilean adults aged ≥18 years in a phase 3 clinical trial. METHODS: Volunteers randomly received 2 doses of CoronaVac or placebo, separated by 2 weeks. A total of 434 volunteers were enrolled, 397 aged 18-59 years and 37 aged ≥60 years. Solicited and unsolicited adverse reactions were registered from all volunteers. Blood samples were obtained from a subset of volunteers and analyzed for humoral and cellular measures of immunogenicity. RESULTS: The primary adverse reaction in the 434 volunteers was pain at the injection site, with a higher incidence in the vaccine than in the placebo arm. Adverse reactions observed were mostly mild and local. No severe adverse events were reported. The humoral evaluation was performed on 81 volunteers. Seroconversion rates for specific anti-S1-receptor binding domain (RBD) immunoglobulin G (IgG) were 82.22% and 84.44% in the 18-59 year age group and 62.69% and 70.37% in the ≥60 year age group, 2 and 4 weeks after the second dose, respectively. A significant increase in circulating neutralizing antibodies was detected 2 and 4 weeks after the second dose. The cellular evaluation was performed on 47 volunteers. We detected a significant induction of T-cell responses characterized by the secretion of interferon-γ (IFN-γ) upon stimulation with Mega Pools of peptides from SARS-CoV-2. CONCLUSIONS: Immunization with CoronaVac in a 0-14 schedule in Chilean adults aged ≥18 years is safe, induces anti-S1-RBD IgG with neutralizing capacity, activates T cells, and promotes the secretion of IFN-γ upon stimulation with SARS-CoV-2 antigens.
Asunto(s)
COVID-19 , Vacunas Virales , Adolescente , Adulto , Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Chile , Método Doble Ciego , Humanos , Inmunogenicidad Vacunal , Inmunoglobulina G , Persona de Mediana Edad , SARS-CoV-2 , Vacunas de Productos Inactivados/efectos adversos , Adulto JovenRESUMEN
Scrub typhus is a potentially fatal rickettsiosis caused by Orientia species intracellular bacteria of the genus Orientia. Although considered to be restricted to the Asia Pacific region, scrub typhus has recently been discovered in southern Chile. We analyzed Orientia gene sequences of 16S rRNA (rrs) and 47-kDa (htrA) from 18 scrub typhus patients from Chile. Sequences were ≥99.7% identical among the samples for both amplified genes. Their diversity was 3.1%-3.5% for rrs and 11.2%-11.8% for htrA compared with O. tsusugamushi and 3.0% for rrs and 14.8% for htrA compared with Candidatus Orientia chuto. Phylogenetic analyses of both genes grouped the specimens from Chile in a different clade from other Orientia species. Our results indicate that Orientia isolates from Chile constitute a novel species, which, until they are cultivated and fully characterized, we propose to designate as Candidatus Orientia chiloensis, after the Chiloé Archipelago where the pathogen was identified.
Asunto(s)
Orientia tsutsugamushi , Tifus por Ácaros , Asia , Chile/epidemiología , Humanos , Orientia , Orientia tsutsugamushi/genética , Filogenia , ARN Ribosómico 16S/genética , Tifus por Ácaros/epidemiologíaRESUMEN
The obligate intracellular bacterium Orientia tsutsugamushi is the causative agent of scrub typhus in humans, a serious mite-borne disease present in a widespread area of endemicity, which affects an estimated 1 million people every year. This disease may exhibit a broad range of presentations, ranging from asymptomatic to fatal conditions, with the latter being due to disseminated endothelial infection and organ injury. Unique characteristics of the biology and host-pathogen interactions of O. tsutsugamushi, including the high antigenic diversity among strains and the highly variable, short-lived memory responses developed by the host, underlie difficulties faced in the pursuit of an effective vaccine, which is an imperative need. Other factors that have hindered scientific progress relative to the infectious mechanisms of and the immune response triggered by this bacterium in vertebrate hosts include the limited number of mechanistic studies performed on animal models and the lack of genetic tools currently available for this pathogen. However, recent advances in animal model development are promising to improve our understanding of host-pathogen interactions. Here, we comprehensively discuss the recent advances in and future perspectives on host-pathogen interactions and the modulation of immune responses related to this reemerging disease, highlighting the role of animal models.
Asunto(s)
Interacciones Huésped-Patógeno/inmunología , Inmunomodulación/inmunología , Orientia tsutsugamushi/inmunología , Tifus por Ácaros/inmunología , Tifus por Ácaros/microbiología , Humanos , Modelos AnimalesRESUMEN
Endemic scrub typhus was recently detected on Chiloé Island in southern Chile. We report a series of cases, acquired over a wide geographical range in continental Chile during 2016-2018, demonstrating that this emerging rickettsial infection is also found on the mainland of South America.
Asunto(s)
Orientia tsutsugamushi , Tifus por Ácaros/epidemiología , Tifus por Ácaros/microbiología , Adulto , Anciano , Animales , Chile/epidemiología , Femenino , Historia del Siglo XXI , Humanos , Inmunoglobulina G/inmunología , Inmunoglobulina M/inmunología , Masculino , Persona de Mediana Edad , Técnicas de Diagnóstico Molecular , Orientia tsutsugamushi/genética , Orientia tsutsugamushi/inmunología , Tifus por Ácaros/historia , Tifus por Ácaros/transmisión , Enfermedades Transmitidas por Vectores , Adulto Joven , ZoonosisRESUMEN
Scrub typhus is a life-threatening zoonosis caused by Orientia tsutsugamushi organisms that are transmitted by the larvae of trombiculid mites. Endemic scrub typhus was originally thought to be confined to the so called "tsutsugamushi triangle" within the Asia-Pacific region. In 2006, however, two individual cases were detected in the Middle East and South America, which suggested that the pathogen was present farther afield. Here, we report three autochthonous cases of scrub typhus caused by O. tsutsugamushi acquired on Chiloé Island in southern Chile, which suggests the existence of an endemic focus in South America. (Funded by the Chilean Comisión Nacional de Investigación Científica y Tecnológica and the Wellcome Trust.).
Asunto(s)
Enfermedades Endémicas , Orientia tsutsugamushi , Tifus por Ácaros , Adulto , Animales , Vectores Arácnidos , Chile , Femenino , Humanos , Masculino , Persona de Mediana Edad , Orientia tsutsugamushi/genética , Orientia tsutsugamushi/aislamiento & purificación , Filogenia , Tifus por Ácaros/diagnóstico , Tifus por Ácaros/microbiología , Tifus por Ácaros/transmisión , Trombiculidae/microbiologíaRESUMEN
BACKGROUND: Coxiella burnetii is an important zoonotic pathogen of global distribution. Still, in most parts of South America including Chile, systematic epidemiological data are lacking. The presented study aims to determine the seroprevalence of Coxiella burnetii antibodies in healthy adults of four different regions in Chile. METHODS: A cross-sectional study was performed, which included healthy adults living in rural and urban areas of four cities located in different regions in northern, central, and southern Chile. In urban sectors, households were chosen by double stratified random sampling, while in rural areas convenience sampling was performed. Serum specimens were taken and screened for the presence of IgG antibodies against C. burnetii phase II antigen using a commercial ELISA kit. Positive and indeterminate results were confirmed by a reference laboratory using indirect immunofluorescence assay (IFA). RESULTS: A total of 1112 individuals were included. Of those, 8 were positive by ELISA, but only one sample was confirmed using IFA. Statistical analysis for population freedom from disease revealed a high probability that C. burnetii was absent in our study population. CONCLUSION: Our work provides the first epidemiological data on human Q fever in Chile indicating either a very low endemicity or the absence of this pathogen in the studied areas.
Asunto(s)
Coxiella burnetii/patogenicidad , Fiebre Q/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Antibacterianos/sangre , Chile/epidemiología , Ciudades , Estudios Transversales , Ensayo de Inmunoadsorción Enzimática , Composición Familiar , Femenino , Técnica del Anticuerpo Fluorescente Indirecta/métodos , Humanos , Masculino , Persona de Mediana Edad , Fiebre Q/microbiología , Población Rural , Estudios Seroepidemiológicos , Población Urbana , Adulto JovenRESUMEN
The measles vaccine has been used for over 50 years and has proven to be safe, effective and inexpensive, Nevertheless, in 2013 145,700 measles deaths occurred, mostly in countries with low per capita income and weak health infrastructure. The occurrence of measles cases is not restricted to developing countries, but also affects developed countries (Europe and USA), where is associated with a reduction in vaccination coverage, explained by a loss of confidence of some parents in the vaccine. This perspective article addresses the loss of confidence in the vaccine, and the individual and collective consequences of the decision to not vaccinate a child. Various strategies to reverse this phenomenon are presented, most notably the continuing education of health professionals, parents and patients using scientific arguments, given in an understandable and interesting language. Finally, the current situation of Chile (a country with current certification of measles elimination) is presented, emphasizing the importance of maintaining this condition.
Asunto(s)
Países Desarrollados/estadística & datos numéricos , Brotes de Enfermedades , Vacuna Antisarampión/administración & dosificación , Sarampión/epidemiología , Niño , Preescolar , Chile , Países en Desarrollo , Femenino , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Sarampión/historia , Sarampión/prevención & controlRESUMEN
BACKGROUND: The genetic analysis of human primary immunodeficiencies has defined the contribution of specific cell populations and molecular pathways in the host defense against infection. Disseminated infection caused by bacille Calmette-Guérin (BCG) vaccines is an early manifestation of primary immunodeficiencies, such as severe combined immunodeficiency. In many affected persons, the cause of disseminated BCG disease is unexplained. METHODS: We evaluated an infant presenting with features of severe immunodeficiency, including early-onset disseminated BCG disease, who required hematopoietic stem-cell transplantation. We also studied two otherwise healthy subjects with a history of disseminated but curable BCG disease in childhood. We characterized the monocyte and dendritic-cell compartments in these three subjects and sequenced candidate genes in which mutations could plausibly confer susceptibility to BCG disease. RESULTS: We detected two distinct disease-causing mutations affecting interferon regulatory factor 8 (IRF8). Both K108E and T80A mutations impair IRF8 transcriptional activity by disrupting the interaction between IRF8 and DNA. The K108E variant was associated with an autosomal recessive severe immunodeficiency with a complete lack of circulating monocytes and dendritic cells. The T80A variant was associated with an autosomal dominant, milder immunodeficiency and a selective depletion of CD11c+CD1c+ circulating dendritic cells. CONCLUSIONS: These findings define a class of human primary immunodeficiencies that affect the differentiation of mononuclear phagocytes. They also show that human IRF8 is critical for the development of monocytes and dendritic cells and for antimycobacterial immunity. (Funded by the Medical Research Council and others.).
Asunto(s)
Células Dendríticas/inmunología , Síndromes de Inmunodeficiencia/genética , Factores Reguladores del Interferón/genética , Mutación , Adolescente , Adulto , Secuencia de Aminoácidos , Animales , Células Presentadoras de Antígenos , Vacuna BCG/genética , Vacuna BCG/inmunología , Femenino , Genes Dominantes , Humanos , Lactante , Factores Reguladores del Interferón/deficiencia , Interleucina-12/biosíntesis , Leucocitos Mononucleares/inmunología , Masculino , Modelos Moleculares , Infecciones por Mycobacterium/genética , Infecciones por Mycobacterium/inmunología , Linaje , Conformación Proteica , Alineación de SecuenciaRESUMEN
Tick-borne rickettsial diseases are potentially life threatening infections that in Latin America have an emerging and reemerging character. Until few years ago, Rickettsia rickettsia was the only tick-borne rickettsia present in America; but nowadays several other species such as R. parkeri and R. massiliae are causing disease in humans in the region. In addition, new species are being described; although their pathogenicity has not been confirmed they should be considered as potential pathogens. Since the microbiological diagnosis of rickettsioses can take days or weeks, a high clinical suspicion and early start of appropriate treatment are crucial. In this review the distribution and main clinical manifestations of tick-borne rickettsial diseases in Latin America are detailed. Since R. felis has been found in ticks and the role of this vector has not been clarified, we have included a section about this pathogen.
Asunto(s)
Infecciones por Rickettsia/clasificación , Rickettsia/clasificación , Enfermedades por Picaduras de Garrapatas/clasificación , Garrapatas/microbiología , Animales , Humanos , América Latina , Rickettsia/aislamiento & purificación , Infecciones por Rickettsia/microbiología , Enfermedades por Picaduras de Garrapatas/microbiologíaRESUMEN
BACKGROUND: The most used test for the diagnosis of viral respiratory infection is the detection of viral antigens by direct immunofluorescence (DFA), in samples taken by nasopharyngeal swab (NPS) or aspirate (NPA). It would be desirable to have a less uncomfortable technique to obtain a sample from the patient, but of equal performance. AIM: To evaluate the diagnostic agreement between nasal swab (NS) and nasopharyngeal swab (NPS) in the detection of respiratory viruses by DFA and compare the degree of discomfort of both techniques in pediatric patients. METHODOLOGY: Cross-sectional study in children who consulted to a pediatric emergency service with respiratory symptoms. Two samples (NPS and NS) per child were collected. The concordance between the two was determined by Kappa (K) coefficient and the degree of discomfort by a visual pain scale. RESULTS: We obtained 112 samples from 56 children, one by each technique. 82.1% were concordant, K = 0.61 (CI 95%, 0.39-0.83) for the detection of any virus, and K = 0.69 (CI 95%, 0.46-0.92) and K = 0.76 (CI 95%, 0.51-1) for syncytial respiratory virus and influenza A detection, respectively. The degree of discomfort was significantly lower for the NS. CONCLUSION: There is considerable agreement in the detection of respiratory viruses by DFA between samples obtained by NS and NPS, but not enough to recommend a change in the sampling method in this population.
Asunto(s)
Mucosa Nasal/virología , Nasofaringe/virología , Infecciones del Sistema Respiratorio/diagnóstico , Adolescente , Niño , Preescolar , Estudios Transversales , Femenino , Técnica del Anticuerpo Fluorescente Directa , Humanos , Lactante , Recién Nacido , Masculino , Infecciones del Sistema Respiratorio/virología , Sensibilidad y Especificidad , Manejo de EspecímenesRESUMEN
INTRODUCTION: Nosocomial infections generate high morbidity and mortality in children undergoing cardiac surgery. OBJECTIVE: To determine risk factors for nosocomial infections in children after congenital heart surgery. METHODS: A retrospective case-control study, in patients younger than 15 years undergoing surgery for congenital heart disease from January 2007 to December 2011 admitted to the Pediatric Critical Patient Unit (UPC-P) in a university hospital. For cases, the information was analyzed from the first episode of infection. RESULTS: 39 patients who develop infections and 39 controls who did not develop infection were enrolled. The median age of cases was 2 months. We identified a number of factors associated with the occurrence of infections, highlighting in univariate analysis: age, weight, univentricular heart physiology, complexity of the surgical procedure according to RACHS-1 and cardiopulmonary bypass (CPB) time ≥ 200 minutes. Multivariate analysis identified CPB time ≥ 200 minutes as the major risk factor, with an OR of 11.57 (CI: 1.04 to 128.5). CONCLUSION: CPB time ≥ 200 minutes was the mayor risk factor associated with the development of nosocomial infections.
Asunto(s)
Infección Hospitalaria/epidemiología , Cardiopatías Congénitas/cirugía , Unidades de Cuidado Intensivo Pediátrico/estadística & datos numéricos , Complicaciones Posoperatorias/epidemiología , Niño , Chile/epidemiología , Infección Hospitalaria/etiología , Femenino , Humanos , Lactante , Masculino , Análisis Multivariante , Complicaciones Posoperatorias/microbiología , Factores de RiesgoRESUMEN
Tick-borne rickettsioses are worldwide infectious diseases that are considered emerging and re-emerging. Until recently the only tick-borne rickettsiosis present in Latin America was Rickettsia rickettsii infection, but to date, with the incorporation of new tools as PCR and sequencing and the quick cellular close tube cultures (Shell-vial), new species has been involved as human pathogens. In these guidelines, we offer an update of the microbiological assays for diagnosing rickettsioses. Besides we have included a section in which the most important hard ticks involved in human rickettsioses in Latinoamerica are detailed.
Asunto(s)
Vectores Arácnidos/microbiología , Infecciones por Rickettsia/diagnóstico , Rickettsia/clasificación , Enfermedades por Picaduras de Garrapatas/diagnóstico , Garrapatas/microbiología , Animales , Técnicas de Cultivo de Célula , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , América Latina , Reacción en Cadena de la Polimerasa , Rickettsia/aislamiento & purificación , Infecciones por Rickettsia/microbiología , Infecciones por Rickettsia/transmisión , Fiebre Maculosa de las Montañas Rocosas/diagnóstico , Fiebre Maculosa de las Montañas Rocosas/microbiología , Enfermedades por Picaduras de Garrapatas/microbiología , Garrapatas/anatomía & histología , Garrapatas/clasificaciónRESUMEN
Background: Vaccine effectiveness against SARS-CoV-2 infection has been somewhat limited due to the widespread dissemination of the Omicron variant, its subvariants, and the immune response dynamics of the naturally infected with the virus. Methods: Twelve subjects between 3-17 years old (yo), vaccinated with two doses of CoronaVac®, were followed and diagnosed as breakthrough cases starting 14 days after receiving the second dose. Total IgGs against different SARS-CoV-2 proteins and the neutralizing capacity of these antibodies after infection were measured in plasma. The activation of CD4+ and CD8+ T cells was evaluated in peripheral blood mononuclear cells stimulated with peptides derived from the proteins from the wild-type (WT) virus and Omicron subvariants by flow cytometry, as well as different cytokines secretion by a Multiplex assay. Results: 2 to 8 weeks post-infection, compared to 4 weeks after 2nd dose of vaccine, there was a 146.5-fold increase in neutralizing antibody titers against Omicron and a 38.7-fold increase against WT SARS-CoV-2. Subjects showed an increase in total IgG levels against the S1, N, M, and NSP8 proteins of the WT virus. Activated CD4+ T cells showed a significant increase in response to the BA.2 subvariant (p<0.001). Finally, the secretion of IL-2 and IFN-γ cytokines showed a discreet decrease trend after infection in some subjects. Conclusion: SARS-CoV-2 infection in the pediatric population vaccinated with an inactivated SARS-CoV-2 vaccine produced an increase in neutralizing antibodies against Omicron and increased specific IgG antibodies for different SARS-CoV-2 proteins. CD4+ T cell activation was also increased, suggesting a conserved cellular response against the Omicron subvariants, whereas Th1-type cytokine secretion tended to decrease. Clinical Trial Registration: clinicaltrials.gov #NCT04992260.
Asunto(s)
Anticuerpos Neutralizantes , Anticuerpos Antivirales , Linfocitos T CD4-Positivos , Vacunas contra la COVID-19 , COVID-19 , SARS-CoV-2 , Adolescente , Niño , Preescolar , Femenino , Humanos , Masculino , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , COVID-19/inmunología , COVID-19/prevención & control , Vacunas contra la COVID-19/inmunología , Vacunas contra la COVID-19/administración & dosificación , Citocinas/inmunología , Citocinas/sangre , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , SARS-CoV-2/inmunología , Vacunación , Estudios de SeguimientoRESUMEN
We report a series of 14 patients from 11 kindreds with recessive partial (RP)-interferon (IFN)-γR1 deficiency. The I87T mutation was found in nine homozygous patients from Chile, Portugal and Poland, and the V63G mutation was found in five homozygous patients from the Canary Islands. Founder effects accounted for the recurrence of both mutations. The most recent common ancestors of the patients with the I87T and V63G mutations probably lived 1600 (875-2950) and 500 (200-1275) years ago, respectively. The two alleles confer phenotypes that are similar but differ in terms of IFN-γR1 levels and residual response to IFN-γ. The patients suffered from bacillus Calmette-Guérin-osis (n= 6), environmental mycobacteriosis (n= 6) or tuberculosis (n= 1). One patient did not suffer from mycobacterial infections but had disseminated salmonellosis, which was also present in two other patients. Age at onset of the first environmental mycobacterial disease differed widely between patients, with a mean value of 11.25 ± 9.13 years. Thirteen patients survived until the age of 14.82 ± 11.2 years, and one patient died at the age of 7 years, 9 days after the diagnosis of long-term Mycobacterium avium infection and the initiation of antimycobacterial treatment. Up to 10 patients are currently free of infection with no prophylaxis. The clinical heterogeneity of the 14 patients was not clearly related to either IFNGR1 genotype or the resulting cellular phenotype. RP-IFN-γR1 deficiency is, thus, more common than initially thought and should be considered in both children and adults with mild or severe mycobacterial diseases.
Asunto(s)
Predisposición Genética a la Enfermedad , Infecciones por Mycobacterium/genética , Receptores de Interferón/deficiencia , Adolescente , Adulto , Secuencia de Aminoácidos , Niño , Preescolar , Femenino , Efecto Fundador , Genes Recesivos , Haplotipos , Humanos , Interferón gamma/metabolismo , Masculino , Datos de Secuencia Molecular , Monocitos/metabolismo , Mutación Missense , Infecciones por Mycobacterium/inmunología , Infecciones por Mycobacterium/microbiología , Mycobacterium avium , Mycobacterium bovis , Osteomielitis/genética , Osteomielitis/microbiología , Linaje , Fenotipo , Fosforilación , Neumonía Bacteriana/genética , Transporte de Proteínas , Receptores de Interferón/genética , Receptores de Interferón/inmunología , Factor de Transcripción STAT1/metabolismo , Salmonella , Infecciones por Salmonella/genética , Tuberculosis/genética , Tuberculosis/microbiología , Tuberculosis/mortalidad , Adulto Joven , Receptor de Interferón gammaRESUMEN
Pet ownership offers undisputed benefits to immunocompromised (IC) patients, however, it poses the risk for potentially serious zoonoses. Mechanisms of transmission and manifestation of major zoonotic infections in dogs and cats that may affect IC patients are described. We also provide updated international information and local data. Recommendations are given to choose and care for pets ensuring safe and responsible ownership. This will help to prevent, detect and treat infections timely.
Asunto(s)
Animales Domésticos , Vínculo Humano-Animal , Huésped Inmunocomprometido , Zoonosis/transmisión , Animales , Animales Domésticos/microbiología , Animales Domésticos/parasitología , Gatos , Perros , Medicina Basada en la Evidencia , Humanos , Factores de Riesgo , Zoonosis/microbiología , Zoonosis/parasitologíaRESUMEN
INTRODUCTION: Candidatus 'Rickettsia andeanae' is recently recognized specie, with no attributed pathogenic role so far. It has been reported in Amblyomma ticks from Peru, USA and Argentina, and recently in Chile, in one specimen of Amblyomma triste from a rural locality in Arica. OBJECTIVE: To determine the presence of rickettsial agents in ticks from domestic dogs from two Chilean regions. METHODS: A transversal descriptive study in Coquimbo and La Araucanía regions, consisted in households sampling in the cities of Coquimbo and Aingol and nearby rural localities, in spring-summer 2011-2012. One dog per house was examined and ticks were collected when present; after taxonomic identification, gltA and ompA genes were amplified and sequenced. RESULTS: 462 dogs were examined, 255 had ticks (55%). In the cities just Rhipicephalus sanguineus was found; in rural localities also Amblyomma tigrinum. Obtained sequences in 12 specimens from A. tigrinum corresponded to Candidatus 'Rickettsia andeanae'. CONCLUSIONS: We documented the presence of R. andeanae in two distant Chilean regions, which is added to its recently finding in the Northern extreme of the country. This new rickettsial agent limits to Amblyomma ticks and rural areas, as it was reported in other American countries and corresponds with this tick habitat.
Asunto(s)
Rickettsia/aislamiento & purificación , Garrapatas/microbiología , Animales , Animales Domésticos/parasitología , Chile , Estudios Transversales , Perros , Filogenia , Reacción en Cadena de la Polimerasa , Rickettsia/clasificación , Rickettsia/genética , Población Rural , Estaciones del Año , Población UrbanaRESUMEN
INTRODUCTION: Laboratory diagnosis of cat scratch disease (CSD) is based on the determination of specific antibodies anti-Bartonella henselae by different techniques. The CDC recommends IgG by immunofluorescent assay (IFA) as the gold standard. OBJECTIVE: To determine the accuracy and diagnostic utility of anti-B.henselae IgM by IFA for CSD. MATERIAL AND METHODS: Anti-B. henselae IgG was determined in serum of 108 patients with CSD suspicion; in addition, specific IgM was determined separately and blindly by two thoroughly trained laboratory professionals. We calculated sensitivity (S), specificity (Sp), predictive values both positive (PPV) and negative (NPV), and likelihood ratio (LR) for IgM positive (LR +) and negative (LR-). RESULTS: In 37 patients with positive anti-B.henselae IgG, IgM was positive in 16 and negative in 21; in 71 patients with negative IgG, IgM was negative in 69 and positive in 2. Therefore, IgM showed S 43%, E 97%, PPV 88%, NPV 77%, LR (+) 15 and LR (-) 0.58. CONCLUSIONS: The results show that a positive IgM supports, but a negative one does not rule out a B. henselae infection. Therefore, IgG should be still considered as the gold standard for the diagnosis of CSD.