Rickettsia rickettsii and Rickettsia typhi in hospitalized children diagnosed with Pediatric Multisystemic Inflammatory Syndrome in Merida, Yucatan

Abstract Multisystem Inflammatory Syndrome in Children (MIS-C) presents with fever, fatigue, elevated inflammatory markers (acute phase reactants), and a history of exposure to SARS-CoV-2 or positive antibodies to SARS-CoV-2. As the COVID-19 pandemic unfolded, the risk of MIS-C in the pediatric population increased. However, exposure to other viruses and the presence of SARS-CoV-2 positive antibodies in children hospitalized for various pathogen-associated illnesses will also remain common and may complicate differential diagnoses with diseases endemic to the region such as rickettsial diseases. The objective was to highlight the desirability of medical personnel systematically incorporating rickettsiosis as a differential diagnosis for MIS-C when studying a child with fever, non-specific symptoms, and elevated inflammatory markers. In conclusion MIS-C should be considered in children with elevated inflammatory markers when there is a history of COVID-19 and they also meet criteria that have already been established by international agencies, such as CDC and WHO

Design and evaluation of a mobile-based intervention for Maya adults during the COVID-19 pandemic

Introduction: The COVID-19 pandemic has had a direct impact on mental health. Inter national organisations have emphasised the vulnerability of indigenous people. Digital Mental Health approaches deliver online therapy as an evidence-based, effective, and accessible treat ment option for common mental health problems. However, the evidence regarding these ap proaches is limited in indigenous populations. The objective of this study is to describe the design, development, and evaluation of the efficacy of a self-applied online intervention regarding the psychological symptoms of depression, anxiety, and fear of COVID-19 in a sample of the Maya population. Method: A prospective longitudinal quantitative study was designed, where a single group was measured before and after receiving the online intervention. This study took place from April to September 2021 and consisted of six sessions delivered via WhatsApp in Spanish and Mayan. Results: The initial assessment was implemented with 82 participants who were evaluated using the Patient Health Questionnaire, Scale for Generalised Anxiety Disorder and the Fear of COVID-19 Scale; 18 participants remained in the intervention for the post-as sessment. Statistical differences were observed in PRE and POST measures of depression and anxiety, but not in fear of COVID-19. Conclusions: This study produced positive results for the first online mental health intervention implemented in the Latin American indigenous pop ulation. Future studies might consider developing similar interventions for other indigenous communities in Latin America.

Introducción: La pandemia de COVID-19 tuvo impacto directo en la salud mental. Organizaciones internacionales han enfatizado la vulnerabilidad de los pueblos indígenas. Los enfoques de salud mental digital brindan terapia en línea como una opción de tratamiento basada en evidencia, efectiva y accesible; sin embargo, los datos son limitados en población indígena. El objetivo de este estudio fue describir el diseño, desarrollo y evaluación de la eficacia de una intervención en línea autoaplicada sobre síntomas psicológicos de depresión, ansiedad y miedo al COVID-19 en una muestra de población maya. Método: Se diseñó un es tudio cuantitativo longitudinal prospectivo, donde se midió a un solo grupo antes y después de recibir la intervención en línea, implementada de abril a septiembre de 2021, que constó de seis sesiones impartidas vía WhatsApp, en español y maya. Resultados: La evaluación inicial se implementó con 82 participantes que fueron evaluados mediante el Cuestionario de Salud del Paciente, Escala para el Trastorno de Ansiedad Generalizada y Escala de Miedo al COVID-19; 18 participantes permanecieron para la evaluación posterior. Se observaron di ferencias estadísticas en las medidas pre- y post- de depresión y ansiedad, pero no miedo al COVID-19. Conclusiones: Este estudio arrojó resultados positivos de la primera intervención de salud mental en línea implementada en la población indígena latinoamericana. Estudios futuros podrían considerar el desarrollo de intervenciones similares para otras comunidades indígenas en América Latina.

A Multiplex PCR assay for a differential diagnostic of rickettsiosis, Lyme disease and scrub typhus

Background & objectives: Coexistence of tick-borne diseases in some regions in Latin America makes the diagnosis difficult due to shared initial signs and symptoms. Rickettsiosis, Lyme disease and recently, scrub typhus are gaining more importance. The objective of this study is to develop a multiplex-PCR assay for a differential diagnosis of rickettsiosis, Lyme disease and scrub typhus. Methods: By using bibliographic and bioinformatic analysis, we identify candidate regions to perform the multiplexPCR assay for Rickettsia sp., Borrelia burgdorferi and Orientia tsutsugamushi as well as identify optimal melting temperature and sensibility analysis. Results: We identified specific primer pairs for Rickettsia sp, Borrelia burgdorferi and Orientia tsutsugamushi with different PCR fragment length but a common melting temperature, 58°C. Interpretation & conclusion: We successfully developed a Multiplex PCR assay for differential diagnosis of rickettsiosis, Lyme disease and scrub typhus that could be a rapid and easy option in clinical and epidemiological practice.Laboratorio de Enfermedades Infecciosas y Parasitarias 1. Unidad Interinstitucional de Investigación Clínica y Epidemiológica, Facultad de Medicina, Universidad Autónoma de Yucatán. Yucatán, Mexico

Laboratorio de Enfermedades Emergentes y Re-emergentes. Centro de Investigaciones Regionales “Dr. Hideyo Noguchi”. Universidad Autonoma de Yucatan. Yucatán, Mexico

Detección de Rickettsia typhi en Rhipicephalus sanguineus s.l. y Amblyomma mixtum en el sur de México / Detection of Rickettsia typhi in Rhipicephalus sanguineus s.l. and Amblyomma mixtum in South Mexico

Resumen: Objetivo: Determinar la presencia de Rickettsia typhi en Rhipicephalus sanguineus s.l. y Amblyomma mixtum, en el sur de México. Material y métodos: Las garrapatas fueron colectadas en humanos y animales domésticos. Se determinó la presencia de Rickettsia por reacción en cadena de la polimerasa (PCR, por sus siglas en inglés) y secuenciación. Resultados: 10/39 viales de trabajo amplificaron fragmentos de los genes gltA, htrA y ompB, en 7/10 proveniente de Rh. sanguineus s.l. colectadas de perros y en 3/10 de A. mixtum colectadas de caballo y humano. La secuenciación indicó R. typhi en Rh. sanguineus y A. mixtum con homología de 100% (LS992663.1), para una región del gen de htrA, y de 99% (LS992663.1), con las regiones de los genes de gltA y OmpB. La tasa mínima de infección (TMI) para R. typhi fue de 3.88. Conclusiones: Las garrapatas Rhipicephalus sanguineus s.l. y Amblyomma mixtum están infectadas naturalmente con R. typhi en el sur de México.

Abstract: Objective: To determine the presence of Rickettsia typhi in Rhipicephalus sanguineuss.l. and Amblyomma mixtum in southern Mexico. Materials and methods: Ticks were collected in humans and domestic animals. The presence of Rickettsia was determined by PCR and sequencing. Results: 10/39 work vials amplified fragments of the gltA,htrA and ompB genes. On 7/10 from Rh. sanguineus s.l collected from dogs and in 3/10 of A. mixtum collected from horse and human. Sequencing indicated R. typhi in Rh. Sanguineus and A. mixtum with 100% homology (LS992663.1) for a region of the htrA gene and 99% (LS992663.1) with the regions of the gltA and OmpB genes. The minimum infection rate (TMI) for R. typhi was 3.88. Conclusions: Rhipicephalus sanguineuss.l. and Amblyomma mixtum are naturally infected with R. typhi in Southern Mexico.

Efectividad de los métodos diagnósticos para la detección de ehrlichiosis monocítica humana y canina / Effectivity of diagnostic methods for the detection of human and canine monocytic ehrlichiosis

Resumen La ehrlichiosis es una enfermedad transmitida por la picadura de garrapatas que afecta a perros y humanos, causada por las especies Ehrlichia canis y E. chaffeensis, respectivamente. Estas bacterias son gramnegativas, intracelulares obligadas, de aspecto cocoide a pleomorfo, que infectan los monocitos y desencadenan síntomas como fiebre elevada, anorexia, trombocitopenia, hemorragias, anemia y problemas graves como esplenomegalia, hepatomegalia y meningitis. Para diagnosticar esta enfermedad existen diversos métodos, entre los que se encuentran los hematológicos que evalúan la morfología de los monocitos en búsqueda de mórulas y la serología, que incluye la búsqueda de anticuerpos anti-Ehrlichia, pero que se encuentra limitado debido a la reactividad cruzada que presenta. Por otra parte, el cultivo de especies de Ehrlichia ha resultado ser un método efectivo para la obtención de antígenos y así desarrollar ensayos por inmunofluorescencia indirecta (IFI). El método por reacción de polimerasa en cadena ofrece un diagnóstico definitivo por tener una mayor sensibilidad y especificidad que los otros métodos, al haberse desarrollado cebadores género-específicos, así como especie-específicos. En esta revisión, se discutirán los diversos métodos aplicados al diagnóstico de esta enfermedad, así como las ventajas y desventajas que estos presentan.

Ehrlichiosis is a disease transmitted by tick's bite that affect dogs and humans caused by the species Ehrlichia canis and E. chaffeensis, respectively. These bacteria are obligated intracellular gram negatives, with a cocoid to pleomorph aspect and can infect monocytes and trigger symptoms such as high fever, anorexia, thrombocytopenia, hemorrhages, anemia, and some serious problems such as splenomegaly, hepatomegaly and meningitis. There are several diagnostic tests for ehrlichiosis such as the hematological ones that evaluate the morphology of the monocytes in search of morulae; serological tests that includes the search of anti-Ehrlichia antibodies, although they might be limited due to cross reaction with other species. In other hand, the culture of Ehrlichia species is an effective method to obtain antigens and even develop indirect immunofluorescence assays (IFA). The polymerase chain reaction offers a definitive diagnosis associated to the use of genus-specific and species-specific primers, as well as its increased sensibility and specificity, compared to the others methods. Thus, in this review, we will discuss various methods applied to the diagnosis of this disease, as well as the advantages and disadvantages that these present.

Importancia de las proteínas OmpA y OmpB en el desarrollo de vacunas contra la Rickettsiosis / Importance of OmpA and OmpB proteins in the development of vaccines against rickettsiosis

RESUMEN Las rickettsiosis son un grupo de enfermedades zoonóticas causadas por bacterias del género Rickettsia, transmitidas por ectoparásitos hematófagos. Debido a su cuadro clínico inespecífico (fiebre, artralgias, mialgias y exantema) es subdiagnosticada y confundida con otras de mayor prevalencia como son el dengue y Chikunguya. Dada su creciente incidencia, se han estudiado antígenos rickettsiales, así como la respuesta inmune que generan con el fin de poder desarrollar vacunas, de ellos los más destacados son las proteínas OmpA y OmpB; en recientes estudios se muestra una respuesta inmune efectiva contra esta enfermedad, por lo que la presente revisión tiene como objetivo brindar un panorama de los resultados obtenidos en estudios enfocados al desarrollo de vacunas a partir de estas proteínas.

ABSTRACT Rickettsioses are a group of zoonotic diseases caused by bacteria of the genus Rickettsia, transmitted by hematophagous ectoparasites. Due to its non-specific clinical characteristics (fever, arthralgia, myalgias and exanthema) is underdiagnosed and confused with others of greater influence such as Dengue, and Chikunguya. In attention to its increasing incidence, rickettsial antigens have been studied along with the immune response they generate, in order to develop vaccines against rickettsiosis, being OmpA and OmpB the most prominent. Recent studies indicate an effective immune response against this disease, so the present review aims to provide an overview of the results obtained in studies focusing in vaccine development using these two proteins.

Long term neurologic sequelae in a Mexican rocky mountain spotted fever case

ABSTRACT During the second half of the twentieth century, neurologic sequelae associated with central nervous system impairment caused by Rickettsia rickettsii were studied widely and exclusively in the United States. We present the case of a Mexican pediatric patient with neurologic sequelae 10 years after an acute infection by R. rickettsii.

Mecanismos de resistencia antifúngica de los azoles en Candida albicans. Una revisión / Mechanisms of antifungal resistance of azoles in Candida albicans. A review

Resumen Candida albicans es una levadura comensal capaz de causar una infección oportunista en hospederos susceptibles denominada candidiasis. El tratamiento para combatir la candidiasis puede ser tópico o sistémico según el tipo de infección, los antifúngicos más utilizados son los derivados imidazólicos (fluconazol, itraconazol, ketoconazol, miconazol etc.), sin embargo en la actualidad se observa una disminución en la efectividad de estos medicamentos, es decir, un fenómeno de resistencia de parte del microorganismo a estos fármacos, esto debido principalmente, al surgimiento de levaduras resistentes, a la aparición de nuevas especies patógenas, a la prescripción irracional de antimicóticos como profilaxis y al aumento de las dosis terapéuticas. Existen dos mecanismos por los que Candida puede adquirir resistencia a un azol. El primero es por mutaciones moleculares de la enzima diana del antifúngico, como la alteración de las enzimas relacionadas en la síntesis del ergosterol y el segundo por la alteración en las bombas de expulsión: ATP-binding cassette (ABC) y facilitadores mayores (MF). En este trabajo se resumen los principales mecanismos de resistencia en Candida y la importancia de hacer pruebas de susceptibilidad con el fin de brindar un tratamiento adecuado para este tipo de infecciones oportunistas.

Abstract Candida albicans is a commensal yeast capable of causing an opportunistic infection called candidiasis in susceptible hosts. Treatment to combat Candida may be topical or systemic according to the type of infection and the imidazole derivatives (fluconazole, itraconazole, ketoconazole, miconazole, etc.) are the antifungals most widely used. However, resistance to these drugs is observed by a decrement in their effectiveness. This is mainly due to the emergence of resistant yeasts and of new pathogenic species, as well as to the irrational prescribing of antifungal prophylaxis and the use of higher therapeutic doses. There are two mechanisms by which Candida can acquire an azole resistance, the first is by molecular mutations of antifungal target enzyme, as the alteration of enzymes related to the synthesis of ergosterols and the second by change in the efflux pumps, such as those of ATP-binding cassette and the higher facilitators. In this work the main mechanisms of resistance to Candida and the importance of performing susceptibility tests in order to provide an adequate treatment for this type of opportunistic infections are summarized.

Rickettsia typhi IN RODENTS AND R. felis IN FLEAS IN YUCATÁN AS A POSSIBLE CAUSAL AGENT OF UNDEFINED FEBRILE CASES / Rickettsia typhi y R. felis en roedores y sus pulgas en Yucatán como posible agente causal de casos febriles indefinidos

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.

Rickettsia typhi es el agente causal del tifo murino; una enfermedad zoonótica transmitida por vector mundialmente distribuida, comúnmente asociada con la presencia de roedores domésticos y silvestres. Los casos humanos de tifo murino en el Estado de Yucatán son frecuentes. Sin embargo, no existe evidencia de la presencia de Rickettsia typhi en mamíferos o vectores en Yucatán. En la búsqueda de vectores y reservorios de Rickettsia typhi, evaluamos la presencia de bacterias del género Rickettsia en roedores y sus ectoparásitos de un pequeño municipio del estado de Yucatán por medio de técnicas de PCR convencional y secuenciación de ADN. Se identificó la presencia de Rickettsia typhi en muestras de sangre obtenidas de Rattus rattus y reportamos por primera vez la presencia de Rickettsia felis en la pulga Polygenis odiosus colectado de Ototylomys phyllotis. Complementariamente, Rickettsia felis fue detectado en la pulga Ctenocephalides felis parasitando al roedor Peromyscus yucatanicus. No se identificó especie de Rickettsia en las muestras de sangre de O. phyllotis y P. yucatanicus analizados. Nuestros resultados contribuyen también en el conocimiento de ciclo de vida biológico del género Rickettsia.

Murine Typhus: Clinical and epidemiological aspects / Tifo Murino: Aspectos clínicos y epidemiológicos

Rickettsia typhi is an intracellular bacteria who causes murine typhus. His importance is reflected in the high frequency founding specific antibodies against R. typhi in several worldwide seroepidemiological studies, the seroprevalence ranging between 3-36%. Natural reservoirs of Rickettsia typhi are rats (some species belonging the Rattus Genus) and fleas (Xenopsylla cheopis) are his vector. This infection is associated with overcrowding, pollution and poor hygiene. Typically presents fever, headache, rash on trunk and extremities, in some cases may occur organspecific complications, affecting liver, kidney, lung or brain. Initially the disease is very similar to other diseases, is very common to confuse the murine typhus with Dengue fever, therefore, ignorance of the disease is a factor related to complications or non-specific treatments for the resolution of this infection. This paper presents the most relevant information to consider about the rickettsiosis caused by Rickettsia typhi

Molecular half-full mechanisms by phagocityc cells on invasive Aspergilosis / Mecanismos moleculares mediados por celulas fagociticas en la aspergilosis invasiva

Fungus from the Aspergillus genus mainly affects lung tissue, occurring when the integrity of the host immunesystem is compromised. The human body uses immunocompetence conditions from mechanical and enzymatic defenses and the action of the innate immune system cells and also uses adaptive responses to control infection. Neutrophils, macrophages, and dendritic cells are critical as antifungal effector cells possess surface receptors that recognize fungal structures and trigger specific responses. TLRs and Dectin-1 the most studied for this interaction. TLRs are responsible for the production and release of cytokines and Dectin-1 is essential in the phagocytosis of theparticle recognition and production of ROS. The best-studied cytokines and its crucial role in the response toAspergillus spp. are TNF-á, IFN-ã, and IL-12. In this work, we reviewed the main mechanisms related to molecularreceptors on phagocytic cells involved in the recognition of Aspergillus spp. Understanding the immune response insituations of immunocompetence and its comparison in immunodeficient organisms could provide alternatives tocontrol invasive aspergillosis.