Abstract Sperm-associated antigen 9 (SPAG9) is a member of cancer-testis antigen, having characteristics of a scaffold protein, which is involved in the c-Jun N-terminal kinase JNK signaling pathway, suggesting its key involvement in different physiological processes, such as survival, apoptosis, tumorigenesis, and cell proliferation. We identified two families (A and B) having multisystem features like coarse facial features, albinism, cataracts, skeletal abnormalities, and developmental delay. Whole genome sequencing (WGS) in families A and B revealed a homozygous frameshift variant (c.903del; p.Phe301Leufs*2) in the SPAG9 gene. Sanger sequencing of both families revealed perfect segregation of the identified variant in all family members. 3D protein modeling revealed substantial changes in the protein’s secondary structure. Furthermore, RT-qPCR revealed a substantial reduction of SPAG9 gene expression at the mRNA level in the affected individuals of both families, thus supporting the pathogenic nature of the identified variant. For the first time in the literature, biallelic SPAG9 gene variation was linked to multisystem-exhibiting features like coarse facial features, albinism, cataracts, skeletal abnormalities, and developmental delay. Thus, this data supports the notion that SPAG9 plays an important role in a multisystemic disorder in humans.

ABSTRACT The characterisation and evaluation of accessions are important steps in both the management of a germplasm collection and in a plant genetic improvement program. Carrying out characterisation and evaluation, whether morphological or molecular, requires observing the overall features of plants in the field, or collecting leaves for DNA extraction, which is time consuming and costly; whereas DNA extracted directly from the seeds allows access to the genome without the need for planting the seeds, which speeds up the selection of genotypes of interest and information on genetic variability. The aim was to develop a non-destructive method for extracting DNA from cashew seeds. The seeds were mechanically perforated using a mini-grinder, and a sample of the endosperm was removed. Various protocols and commercial kits for DNA extraction were tested, as well as materials to seal the opening made in the seed. It is possible to extract cashew tree DNA from the endosperm, preferably using commercial kits with cementitious adhesive as the sealing material, offering a germination percentage of 60% of the perforated seeds. program molecular field costly variability nondestructive non destructive minigrinder, minigrinder mini grinder, grinder mini-grinder removed tested seed material 60 6

Abstract Early puberty is associated with improved long-term reproductive performance. Predicting who will achieve early puberty is limited to intensive, invasive serial blood collections for measurement of reproductive hormones. The vaginal genome during pubertal development has potential as biomarkers of early estrus in the pre-pubertal period. Pre-pubertal gilts (n =13) were followed from d74 ± 3 of age until first estrus or d214 ± 1 of age. Blood, vaginal epithelia, and anogenital distance were collected at five timepoints during reproductive development (d74, d104, d130, d160 and first estrus or end of trial). Total RNA was isolated from vaginal epithelia and relative gene expression of two toll-like receptors (TLR-4 and TLR-5), tacykinin precursor-3 (TAC-3), insulin-like growth factor-1 (IGF-1), and estrogen receptor (ERα)-alpha was quantified by real time RT-PCR, relative to expression of RPLP0. Four gilts exhibited estrus early (< d184), 3 were average (d194 to 195), 3 were late (d203 to 213), and 3 were deemed anestrus. Comparison of expression of each gene relative to d70 was performed using the PCR package in RStudio (version 1.2.5025) and Fisher’s exact t-test for TLR-4, TLR-5 and TAC-3, and ANOVA for ER-alpha and IGF-1. Correlation analysis examined the relationship between anogenital distance and age at first estrus. A single blood draw for serum progesterone was obtained 8 days after recorded first estrus or end of trial; the presence of serum progesterone supports the visual identification of standing estrus. Expression of IGF-1 and TAC-3 were up-regulated 9- and 7-fold, respectively at d160 (P < 0.05). Expression of ERα tended to be upregulated 3-fold at d104 (P = 0.08) and expression of TLR-4 and TLR-5 was not detected until first estrus. Anogenital distance was positively correlated to the first estrus. These transcripts associated with reproduction warrant further investigation into use as biomarkers to detect early estrus. longterm long term performance intensive hormones prepubertal pre period Prepubertal Pre n =13 13 d d7 d21 Blood d74, (d74 d130 d16 trial. trial . trial) tolllike toll like TLR4 TLR 4 (TLR- TLR5, TLR5 5 , TLR-5) precursor3 precursor precursor- TAC3, TAC3 TAC (TAC-3) insulinlike insulin factor1 factor factor- IGF1, IGF1 IGF (IGF-1) ERαalpha alpha RTPCR, RTPCR RT PCR, RT-PCR RPLP0 RPLP ( d184, d184 d184) d194 (d19 195, 195 195) d203 (d20 213, 213 213) anestrus version 1.2.5025 125025 2 5025 Fishers Fisher s ttest t test TLR4, 4, TLR- 3, ERalpha ER IGF1. 1. IGF- TAC- up regulated 9 7fold, 7fold fold 7 fold, 7-fold P 0.05. 005 0.05 0 05 0.05) 3fold d10 0.08 008 08 =1 d2 (d7 d13 d1 (TLR (TAC-3 (IGF-1 d18 d19 (d1 19 d20 (d2 21 1.2.502 12502 502 00 0.0 (d (TAC- (IGF- 1.2.50 1250 50 0. (TAC (IGF 1.2.5 125 1.2. 12 1.2

ABSTRACT Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli, is the main bacterial disease affecting the production of beans (Phaseolus vulgaris L.), with significant impacts on Brazilian agriculture. The search for resistant genotypes is a fundamental strategy, given the prevalence and persistence of the pathogen in tropical conditions. Therefore, this study aimed to identify candidate genes for resistance to CBB through association mapping studies, using 126 Middle-American bean genotypes from the germplasm bank of the Instituto de Desenvolvimento Rural do Paraná. A randomized block design with four replications was used. The inoculation method was by cutting the leaves with scissors, using the isolate Xap-139y at a concentration of 107 CFU·mL-1, and the variables final score and area under the disease progress curve (AUDPC) were evaluated. The expected performance of the means and the genetic parameters were estimated using the Selegen software. The GEN203 genotype was considered resistant for AUDPC and final score. Using multi-locus models (FASTmrMLM, ISIS-EM-BLASSO, mrMLM, pLARmEB), we identified 11 quantitative trait nucleotides associated with CBB resistance and 48 candidate genes in the resistance response. These genes act in several metabolic pathways, suggesting a complex polygenic inheritance. This work contributes significantly to understanding the genetic basis of resistance to CBB and the development of bean cultivars with better adaptability and productivity in regions affected by the disease. CBB, , (CBB) pv phaseoli Phaseolus L., L L. L.) agriculture strategy conditions Therefore studies 12 MiddleAmerican Middle American Paraná used scissors Xap139y Xapy Xap 139y y 10 CFU·mL1, CFUmL1 CFUmL CFU·mL 1, CFU mL 1 CFU·mL-1 (AUDPC evaluated software GEN GEN20 multilocus multi locus FASTmrMLM, FASTmrMLM (FASTmrMLM ISISEMBLASSO, ISISEMBLASSO ISIS EM BLASSO, BLASSO ISIS-EM-BLASSO mrMLM pLARmEB, pLARmEB pLARmEB) 4 response pathways inheritance (CBB mL1 CFU·mL1 CFU·mL- GEN2

Resumen Introducción. La producción de banano es una de las actividades económicas más significativas para el país. Sin embargo, enfrenta serios desafíos debido a la presencia de diversos patógenos, entre los más significativos se encuentran los nematodos fitoparásitos que afectan el rendimiento y la calidad del cultivo. El uso de hongos nematófagos (HN) para el control biológico de nematodos es una alternativa para reducir la aplicación de productos químicos en cultivos agrícolas. En Costa Rica existe gran variedad de hongos debido a la diversidad de los suelos, por lo que el aislamiento y la correcta identificación de estos hongos es crucial para determinar su potencial antagonista. Objetivo. Aislar e identificar potenciales hongos nematófagos (PHN) presentes en muestras de suelo de plantaciones de banano de la región Huetar Atlántica. Materiales y métodos. Se analizaron seis muestras de suelo provenientes de cinco cantones de la región Huetar Atlántica de Costa Rica mediante el método de espolvoreado en placas con agar-agua en búsqueda de PHN. Para la selección y purificación de los PHN se utilizaron placas Petri con papa dextrosa agar (PDA), identificando las estructuras morfológicas para el diagnóstico a nivel de género. Los hongos identificados morfológicamente se replicaron y se conservaron en viales con PDA y en aceite mineral a 4°C. Se extrajo ADN de los PHN y mediante amplificación por PCR (Reacción de Cadena de la Polimerasa) y secuenciación de diferentes regiones del genoma (ITS, tef 1-alfa, rpb2 y β-tubulina), se identificaron molecularmente. Resultados. Se aislaron e identificaron doce hongos, entre ellos Trichoderma asperellum, Penicillium steckii, Purpureocillium lilacinum, Fusarium oxysporum, Fusarium sp., Fusarium pseudocircinatum, y Talaromyces sp. Conclusión. El descubrimiento e identificación correcta de PHN subraya la importancia de investigar su aplicación en programas de manejo integrado de plagas, así como la necesidad de evaluar su eficacia y seguridad en diferentes condiciones agroecológicas para maximizar su impacto positivo en la agricultura.

Abstract Introduction. Banana production is one of the most significant economic activities for the country. However, it faces serious challenges due to the presence of various pathogens, among the most significant are plant-parasitic nematodes that affect crop yield and quality. The use of nematophagous fungi (NF) for biological control of nematodes is an alternative to reduce the application of synthetic chemicals in agricultural crops. In Costa Rica there is a great variety of fungi due to the diversity of soils. Therefore, the isolation and correct identification of these fungi is crucial to determine their antagonistic potential. Objective. To isolate and identify the potential nematophagous fungi (PNF) present in soil samples from banana plantations at the Huetar Atlantic region. Materials and methods. Six soil samples from the Huetar Atlantic region of Costa Rica were analyzed by the agar-water sprinkling plates method in search of PNF. For PNF selection and purification, Petri dishes with potato dextrose agar (PDA) were used, identifying morphological structures for diagnosis at genus level. Morphologically identified fungi were replicated and preserved in vials with PDA and in mineral oil at 4°C. DNA was extracted from the isolated PNF and through PCR amplification (Polymerase Chain Reaction) and sequencing of different regions of the genome (ITS, tef 1-alpha, rpb2 and β-tubulin), they were molecularly identified. Results. Twelve fungi were isolated and identified, including Trichoderma asperellum, Penicillium steckii, Purpureocillium lilacinum, Fusarium oxysporum, Fusarium sp., Fusarium pseudocircinatum, and Talaromyces sp. Conclusion. The correct discovery and identification of PNF underscores the importance of investigating its application in integrated pest management programs, as well as the need to evaluate its efficacy and safety under different agroecological conditions to maximize its positive impact on agriculture.

Resumen Introducción: Anoectochilus formosanus es una orquídea herbácea muy valiosa, conocida por su eficacia en el tratamiento de una amplia gama de enfermedades. Sin embargo, los métodos actuales utilizados para diferenciar esta especie de otras dentro del mismo género no son efectivos debido a la gran similitud en las características morfológicas y las secuencias de códigos de barras de ADN entre estas especies. Objetivo: Caracterizar el genoma del cloroplasto (cp) para distinguir A. formosanus a nivel de especie o de aislamiento. Métodos: El genoma completo del cp se secuenció utilizando tecnología de secuenciación de nueva generación, se anotó y se comparó con los genomas del cp publicados de varias especies del género Anoectochilus. Resultados: El genoma del cp completo de A. formosanus tiene un tamaño de 152 658 pb y consta de una copia grande y pequeña de 82 692 pb y 17 346 pb, respectivamente, separadas por repeticiones invertidas de 26 310 pb. Dentro del genoma del cp, hay un total de 141 genes, incluidos 92 genes codificadores de proteínas, 10 genes de ARNr y 39 genes de ARNt. Este genoma contiene un total de 80 repeticiones de secuencia simple, con 50 repeticiones largas. Mediante análisis filogenético, se observó una estrecha relación entre A. formosanus de Vietnam y muestras de A. formosanus de China (NC_061756.1). Sin embargo, las comparaciones genómicas resaltaron diferencias entre los dos genomas del cp, específicamente en sus secuencias de repetición invertida. Conclusión: Estos hallazgos revelan distintas variaciones en el genoma del cp de A. formosanus en Vietnam, lo que ofrece información valiosa sobre la taxonomía, la identificación de plantas, la reproducción y los programas de conservación relacionados con esta hierba en Vietnam.

Abstract Introduction: Anoectochilus formosanus is a highly valuable herb known for its efficacy in treating a wide range of diseases. However, the current methods used to differentiate this species from others within the same genus are not effective due to the high similarity in morphological characteristics and DNA barcode sequences among these species. Objective: To characterize the chloroplast (cp) genome to distinguish A. formosanus at species or isolation levels. Methods: The complete cp genome was sequenced using next-generation sequencing technology, annotated, and compared with published cp genomes of various species within the Anoectochilus genus. Results: The complete cp genome of A. formosanus is 152 658 bp in size, consisting of a large and small copy of 82 692 bp and 17 346 bp, respectively, separated by inverted repeats of 26 310 bp. Within the cp genome, there are a total of 141 genes, including 92 protein-coding genes, 10 rRNA genes, and 39 tRNA genes. This genome contains a total of 80 simple sequence repeats, with 50 long repeats. Through phylogenetic analysis, a close relationship was observed between A. formosanus in Vietnam and A. formosanus samples from China (NC_061756.1). However, genomic comparisons highlighted differences between the two cp genomes, specifically in their reverse repeat sequences. Conclusion: These findings reveal distinct variations in the cp genome of A. formosanus in Vietnam, offering valuable insights into the taxonomy, plant identification, breeding, and conservation programs related to this herb in Vietnam.

Resumen Durante las últimas décadas la medicina genómica ha llevado al ámbito de la consulta médica los conoci mientos de la genética molecular. Existe un número de estudios que contribuyen en el diagnóstico, la definición de pronósticos y posibilitan un asesoramiento genético basado en datos científicos certeros. En algunas enfer medades, los avances en la secuenciación genómica, ha promovido la reclasificación de entidades según un criterio etiológico, como las encefalopatías epilépticas, las ataxias, las distonías, entre muchas condiciones médicas. Su implementación requiere, por parte de los médicos, de estrategias tendientes a alcanzar el mejor rédito diagnóstico. Es necesario para ello, una mayor comprensión de las bases moleculares de estas prácti cas, así como sus alcances. Permiten reducir los tiempos hasta la concreción de un diagnóstico de certeza y la posibilidad, en algunos casos, de mejorar la calidad de vida de los afectados con la utilización de tratamientos a la medida. El objetivo de este artículo fue describir las técnicas de laboratorio actuales, sus alcances y enfatizar los algoritmos de estudio de las enfermedades genéticas, haciendo hincapié en aquellas propias de la neurope diatría, a fin de propiciar las buenas prácticas, evitando confusiones, errores, erogaciones innecesarias de dinero y acortando la llamada “odisea diagnóstica”.

Abstract During the last decades, genomic medicine has made it possible to bring the knowledge of molecular genetics to the field of medical consultation. There are several studies that contribute to the diagnosis, the definition of prognoses, as well as the possibility of providing genetic counseling based on accurate scientific data. Advances in genomic sequencing have promoted the reclassifica tion of entities according to an etiological criterion. Such is the case of epileptic encephalopathies, ataxias, dystonias, among many other neurological conditions. Its implementation requires strategies aimed at achiev ing the best diagnostic yield. This requires a greater understanding of the molecular bases of each of these practices, as well as their scope. They allow reducing the time until a certain diagnosis is made and the possibility, in some cases, of improving the quality of life of those affected with the use of tailored treatments. The objective of this article was to describe current laboratory studies, their scope and emphasize the algo rithms for the study of genetic diseases in general, fo cusing the attention on those specific to neuropediatrics, in order to promote good practices, avoiding confusion, errors, and unnecessary expenditures of money and shortening the so-called “diagnostic odyssey”.

Abstract: Inherited Bone Marrow Failure syndromes account for approximately 25% of cases of aplastic anemia in pediatric patients. Next-generation sequencing (NGS) technologies have allowed the diagnosis of an increasing number of hereditary causes of bone marrow failure. Objective: To determine the diagnostic yield and clinical concordance of NGS in the diagnosis of a cohort of pediatric patients with bone marrow failure. Patients and Method: Patients included were those aged between 0-17 years with a diagnosis of Bone Marrow Failure Syndrome according to the ICD-10 classification codes, who had undergone a genetic study between 2018 and 2022. The information was obtained from the electronic medical records system. Genomic DNA was isolated and quantified through the Qubit™ 3.0 fluorometer. Regions of interest were selected using a hybridization probe that included the intronic and exonic regions adjacent to the genes included in the panel. Clonal amplification and paired-end sequencing of the selected regions were performed using the Illumina MiSeq™ system. Bioinformatics analysis was performed in alignment with the reference genome (GRCh38). Variants classified as probably pathogenic or pathogenic were confirmed through Sanger sequencing. Results: Out of 18 patients included, a genetic diagnosis was achieved through NGS in 5 (27.8%) of them: two cases of Fanconi Anemia, two cases of Dyskeratosis Congenita, and one case of TP53- associated bone marrow failure. Clinical concordance was 100%. Two novel variants were found in the FANCA and PARN genes as causing disease. Conclusions: The use of NGS in patients with bone marrow failure identified the etiology in close to a third of patients of our cohort, with higher yield in patients with a clear clinical diagnosis and syndromic features.

Resumen: Los síndromes hereditarios de falla medular representan aproximadamente el 25% de los casos de anemia aplásica en la población pediátrica. Las tecnologías de Secuenciación de Nueva Generación (NGS) han permitido el diagnóstico de un número cada vez mayor de etiologías hereditarias de falla medular. Objetivo: Determinar el rendimiento y la concordancia clínica de la NGS en el diagnóstico de una cohorte de pacientes con falla medular. Pacientes y Método: Se incluyeron pacientes entre 0 y 17 años con diagnóstico de Síndrome de Falla Medular de acuerdo con los códigos de la clasificación CIE-10, a quienes se les hubiera realizado estudio genético entre 2018 y 2022. La información fue obtenida a partir del sistema de historias clínicas electrónicas. Se aisló ADN genómico y se cuantificó a través del fluorómetro Qubit®3.0. Las regiones de interés fueron seleccionadas utilizando una sonda de hibridización que incluía las regiones intrónicas y exónicas adyacentes a los genes incluidos en el panel. Se realizó amplificación clonal y secuenciación de extremos apareados de las regiones seleccionadas a través de la plataforma Illumina MiSeq. El análisis bioinformático se realizó en alineamiento con el genoma de referencia (GRCh38). Las variantes clasificadas como probablemente patogénicas o patogénicas fueron confirmadas a través de secuenciación Sanger. Resultados: De los 18 pacientes incluidos, se encontró un diagnóstico genético a través de NGS en 5 (27,8%): dos casos de anemia de Fanconi, dos casos de Disqueratosis Congénita y un caso de falla medular asociada a una variante patogénica en el gen TP53. La concordancia clínica fue del 100%. Se encontraron dos variantes no reportadas en los genes FANCA y PARN como causantes de enfermedad. Conclusiones: El uso de NGS en pacientes con falla medular identificó la etiología de cerca de un tercio de los pacientes de nuestra cohorte, con mayor rendimiento en los pacientes con diagnóstico clínico claro y otras características sindrómicas.

Abstract Background Merkel cell polyomavirus (MCPyV), a human polyomavirus that is unequivocally linked to merkel cell carcinoma (MCC), has been found in association with keratinocytes carcinomas (KC), especially basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC). Nevertheless, there is scarce information about the possible involvement of MCPyV in the development of KC. Objectives To assess the presence of MCPyV DNA and Large-T Antigen (LT-Ag) via Polymerase Chain Reaction (PCR) and Immunohistochemistry (IHC) in cases of KC, and to correlate its presence with immunohistochemical markers p16, p53, and ki67, tumor type and subtype, sun-exposed location, and epidemiological data. Methods The prevalence of MCPyV DNA, LT-Ag, and immunohistochemical markers p16, p53, and ki67 was assessed by PCR and Immunohistochemistry (IHC) in 127 cases of KC, these results were correlated with tumor type and subtype, sun-exposed location, and epidemiological data. Results The MCPyV DNA was detected in 42.57% (43 of 101) cases by PCR, the LT-Ag was detected in 16.4% (20 of 122) of cases, p16 in 81.5% (97 of 119), p53 in 66.4% (83 of 125), ki67 in 89% (73 of 82). No correlation between MCPyV LT-Ag and DNA confronted with tumor type, subtype, location site, and immunohistochemical markers was found. A single correlation between the MCPyV LT-Ag and cSCC tumors and peri-tumoral lymphocyte cells was noted. Study limitations Further steps need to be taken to better evaluate the MCPyV influence and its possible role in KC carcinogenesis, as the evaluation of the virus genome state, the gene sequence that encodes LT-Ag in the KC tumor cells, and in situ hybridization for viral DNA or RNA in these cells. Conclusions Despite the frequent detection of MCPyV in KC, the data available so far does not support the hypothesis of a causal relationship between them. MCPyV, , (MCPyV) MCC, MCC (MCC) (KC) BCC (BCC cSCC. . (cSCC) Nevertheless LargeT Large T LTAg LT Ag (LT-Ag (PCR IHC (IHC p ki subtype sunexposed sun exposed LTAg, Ag, ki6 12 4257 42 57 42.57 43 (4 101 164 16 4 16.4 20 (2 122 p1 815 81 5 81.5 97 (9 119, 119 119) p5 664 66 66.4 83 (8 125, 125 125) 89 73 (7 82. 82 82) site peritumoral peri tumoral noted carcinogenesis state them (MCPyV (MCC (KC (cSCC 1 425 42.5 ( 10 16. 2 8 81. 9 11 6 66. 7 42.

RESUMEN El viroide del enanismo del lúpulo (HSVd) es el agente causal de la cachexia de los cítricos, que puede provocar pérdidas significativas en el cultivo. Como parte de una estrategia de manejo preventivo, es indispensable utilizar plantas sanas provenientes de un programa de certificación. Este estudio tuvo como objetivo evaluar la sanidad de 17 cultivares de cítricos frente a HSVd, utilizando diagnósticos biológico y molecular. Para el diagnóstico biológico, se empleó como planta indicadora cidro Etrog (Citrus medica L.) clon Arizona 861 S1, incluyendo controles negativos y positivos para la infección por HSVd. Para el diagnóstico molecular se utilizó la técnica de Reacción en Cadena de la Polimerasa con Transcriptasa Inversa (RT-PCR) con cebadores específicos para la detección del viroide. Los resultados indicaron que seis meses después de la inoculación, el control positivo mostró síntomas asociados con la infección por el viroide, como necrosis en el peciolo y tallo, epinastia foliar y necrosis en vena media. Por el contrario, tanto el control negativo como los cultivares de cítricos evaluados no presentaron síntomas. Estos resultados fueron corroborados por el análisis molecular, que permitieron amplificar una región del genoma del viroide, únicamente en el control positivo. Ambos diagnósticos biológico y molecular confirmaron la ausencia de HSVd en las variedades de cítricos evaluadas. Este estudio permitirá la evaluación de las colecciones de plantas de cítricos utilizadas en la categoría fundación como fuente de yemas para la multiplicación de semilla registrada y certificadapara los viveros productores de material de propagación de cítricos en Colombia.

ABSTRACT Hop stunt viroid (HSVd) is the causal agent of citrus cachexia, which can lead to significant crop losses. As part of a preventive management strategy, it is essential to use healthy plants from a certification program. This study aimed to evaluate the healthiness of 17 citrus cultivars against HSVd using both biological and molecular diagnostics. For biological diagnosis, Etrog citron (Citrus medica L.) clone Arizona 861 S1 was used as an indicator plant, incorporating negative and positive controls for HSVd infection. For molecular diagnosis, reverse transcription polymerase chain reaction (RT-PCR) technique was employed with specific primers for viroid detection. Results indicated that six months after inoculation, the positive control exhibited symptoms associated with viroid infection, such as necrosis in the petiole and stem, leaf epinasty, and necrosis in the midvein. In contrast, both the negative control and evaluated citrus cultivars showed no symptoms. These findings were supported by molecular analysis, which allowed the amplification of a viroid genome region only in the positive control. Both biological and molecular diagnosis confirmed the absence of HSVd in the citrus varieties assessed. This study will allow the evaluation of the citrus plant collections used in the foundation category as a source of buds for plant multiplication of registered and certified seeds for citrus propagation nurseries in Colombia.

RESUMEN Introducción: El virus chikungunya (CHIKV), es un alfavirus con genoma de ARN monocatenario, perteneciente a la familia Togaviridae, transmitido a través de la picadura de mosquitos del género Aedes sp., caracterizada por fiebre y dolores articulares incapacitantes. Objetivo: Determinar las características clínicas y epidemiológicas del virus chikungunya en pacientes pediátricos que acudieron a un Hospital Regional de Paraguay entre enero y junio del 2023. Material y Métodos: Estudio cuantitativo, observacional, descriptivo de corte transversal. Se incluyeron en el estudio todos los pacientes que presenten variables de interés; sexo, edad, procedencia, hallazgos clínicos y síntomas atípicos. Resultados: Se ha realizado la revisión de 465 fichas clínicas de pacientes con cuadro confirmado de chikungunya. La edad mínima de los pacientes fue de 4 días y la máxima de 17 años, la mitad de los pacientes estuvieron ubicados entre 1 y 10 años de edad. El 62,6% tuvo una presentación típica del cuadro de infección por chikungunya, el 37,4% tuvo una forma de presentación atípica. El 4,3% presentó complicaciones entre las que se citan encefalitis-meningoencefalitis y miocarditis. El 10,8% tuvo desenlace fatal, obitó. Conclusión: En cuanto a los datos demográficos, hubo predominio del sexo masculino y procedencia urbana. En cuanto a la presentación clínica, se reportaron formas típicas con fiebre, polialtralgias y mialgias. Las formas atípicas se presentaron con alteración del sistema cardiovascular, discrasia sanguínea y neumonías asociadas. Los casos que se consideraron complicados representan el 4,3% de la muestra y fue del 10,8% la mortalidad.

ABSTRACT Introduction: Chikungunya virus (CHIKV) is an alphavirus with a single-stranded RNA genome belonging to the Togaviridae family. It is transmitted through the bite of mosquitoes of the Aedes sp. genus and is characterized by fever and disabling joint pain. Objetive: Determine the clinical and epidemiological characteristics of the chikungunya virus in pediatric patients who attended a Regional Hospital in Paraguay between January and June 2023. Materials and method: Quantitative, observational, descriptive cross-sectional study. All patients with variables of interest were included in the study; sex, age, origin, clinical findings and atypical symptoms. Results: A total of 465 clinical records of patients with confirmed chikungunya were reviewed. The minimum age of the patients was four days, and the maximum was 17 years; half of the patients were between 1 and 10 years of age. Male predominance in 52.7%, patients from urban areas in 72.5%. 62.6% had a typical presentation of chikungunya infection, and 37.4% had an atypical presentation. Fever, polyarthralgia, myalgia, headache, vomiting, and nausea predominated in the usual manner. In the atypical form, alterations of the cardiovascular system, bleeding dyscrasias, and pneumonia, among others, predominate. 4.3% presented complications, including encephalitis-meningoencephalitis and myocarditis. There was a death rate of 10.8%. Conclusion: Male sex predominated, coming from urban areas with typical presentation of chikungunya, with predominant symptoms of fever, polyarthralgia, and myalgia. Atypical form alteration of the cardiovascular system, bleeding dyscrasias, pneumonia. 4.3% presented complications, 10.8% died.