Seroincidencia de anticuerpos IgG del SARS-CoV-2 y factores de riesgo en trabajadores sanitarios asintomáticos del hospital Departamental de Villavicencio

Objetivo: Estimar la seroincidencia acumulada de inmunoglobulinas (Ig) clase G (IgG) anti-SARS-CoV-2 en trabajadores de la salud asintomáticos y su asociación epidemiológica dentro de las áreas funcionales del Hospital Departamental de Villavicencio (HDV). Metodología: Se llevó a cabo un estudio observacional analítico longitudinal de una cohorte de trabajadores, donde cada 21 días, en tres oportunidades, se midieron IgG anti-SARS-CoV-2 en suero sanguíneo, a través de ELISA indirecto, en una muestra representativa aleatoria (n= 105) de trabajadores sanitarios del hospital (N= 756). Como instrumento de recolección de datos se utilizó una encuesta, donde cada trabajador sanitario declaró no haber sido diagnosticado con COVID-19, e igualmente registró la información sobre las variables independientes: sexo, edad, condición laboral, área funcional y comorbilidades. Resultados: La prevalencia inicial para SARS-CoV-2 entre los trabajadores sanitarios asintomáticos del HDV fue de 9,52 % (IC 95 % 5,25-16,65). La seroincidencia acumulada durante 42 días fue de 12,38 % (IC 95 % 7,38-20,04). El riesgo relativo (RR) se utilizó para establecer los factores de riesgo asociados a las variables independientes. El sexo masculino (RR ajustado = 3,34, IC 95 % 1,98-5,86), obesidad (RR ajustado = 10,98, IC 95 % 1,41-85,98) y sexo femenino (RR ajustado = 2,15, IC 95 % 1,12-4,31) en las áreas funcionales de Hospitalización, Medicina Crítica y Urgencias, respectivamente, son factores de riesgo en el HDV. Conclusión: Un total de 13 de 105 trabajadores sanitarios del hospital seroconvirtieron positivamente para SARS-CoV-2 y fueron asintomáticos durante 42 días de seguimiento epidemiológico. Además, existen factores de riesgo importantes en su exposición a este virus en el HDV.

Objective: To estimate the cumulative seroincidence of antisars-CoV-2 immunoglobulin (Ig) class G (IgG) in asymptomatic health care workers and its epidemiological association within the functional areas of the Villavicencio Departmental Hospital (HDV). Methodology: A longitudinal analytical observational study of a cohort of workers was conducted in which anti- SARS-CoV-2 IgG levels in blood serum were measured every 21 days on three occasions using an indirect ELISA in a random representative sample (n = 105) of hospital health workers (N = 756). The data collection tool was a survey in which each healthcare worker indicated that they had not been diagnosed with COVID-19 and provided information on the independent variables: sex, age, job status, functional area, and comorbidities. Results: The baseline prevalence for SARS-CoV-2 among asymptomatic HDV healthcare workers was 9.52% (CI 95% 5.25-16.65). Cumulative seroincidence over 42 days was 12.38% (CI 95% 7.38-20.04). Relative risk (RR) was used to establish the risk factors associated with the independent variables. Male sex (adjusted RR 3.34, CI 95% 1.98-5.86), obesity (adjusted RR 10.98, CI 95% 1.41- 85.98) and female sex (adjusted RR 2.15, CI 95% 1.12-4.31) in the functional areas of Hospitalization, Critical Medicine and Emergency, respectively, are risk factors in the HDV. Conclusion: During 42 days of epidemiological follow-up, 13 out of 105 hospital healthcare workers seroconverted positively for SARS-CoV-2 and remained asymptomatic. Additionally, significant risk factors are associated with their exposure to this virus in the HDV.

Objetivo: Estimar a incidência zero acumulada de imunoglobulinas (Ig) classe G (IgG) anti-SARS-CoV-2 em profissionais de saúde assintomáticos e sua associação epidemiológica dentro das áreas funcionais do Hospital Estadual de Villavicencio (HDV). Metodologia: Foi realizado um estudo observacional analítico longitudinal de uma coorte de profissionais, no qual a cada 21 dias, em três ocasiões mediram-se IgG anti-SARS-CoV-2 em soro sanguíneo, através de ELISA indireto, em uma amostra representativa aleatória (n = 105) de profissionais de saúde do hospital (N =756). Como instrumento de recolecção de dados foi usada uma pesquisa, onde cada profissional de saúde declarou não ter sido diagnosticado com COVID-19, e igualmente registrou a informação sobre as variáveis independentes: sexo, idade, condições de trabalho, área de atuação e comorbidades. Resultados: A prevalência inicial para SARS-CoV-2 entre os profissionais de saúde assintomáticos do HDV foi de 9,52% (IC 95% 5,25-16,65). A incidência zero acumulada durante 42 dias foi de 12,38% (IC 95% 7,38-20,04). O risco relativo (RR) foi utilizado para estabelecer os fatores de risco associados às variáveis independentes. O sexo masculino (RR ajustado 3,34, IC 95% 1,98-5,86), obesidade (RR ajustado 10,98, IC 95% 1,41-85,98) e sexo feminino (RR ajustado 2,15, IC 95% 1,12-4,31) nas áreas funcionais de Internação, Unidade de Terapia Intensiva e Urgências, respectivamente, são fatores de risco no HDV. Conclusão: Um total de 13 de 105 profissionais de saúde do hospital foram detectados positivamente para SARS-CoV-2 e foram assintomáticos durante 42 dias de seguimento epidemiológico. Além disso, existem importantes fatores de risco na sua exposição a este vírus no HDV.

Protective response mediated by immunization with recombinant proteins in a murine model of toxocariasis and canine infection by Toxocara canis.

Toxocariasis is a neglected parasitic zoonosis of global importance. The development of a formulation that can be used as a vaccine would help the definitive control of the infection. Preclinical studies selected two recombinant T. canis proteins (rTcVcan and rTcCad) which significantly protected mice against larval migration. In the present work, these proteins plus three adjuvants (Alhydrogel®, PAM3CSK4®, and Quil-A®) were used to immunize mice against toxocariasis; blood samples were collected three times to measure IgG (total, IgG1, IgG2a), IgA, and IgE via indirect ELISA. Cytokines (IL-5, TNF-α, and IL-10) were measured in splenocytes supernatant, and T. canis larvae were quantified in tissues. The best protein + adjuvant pair found (rTVcan + QuialA®) was then used to immunize T. canis-free puppies (n = 18) that were experimentally infected with T. canis and T. canis naturally-infected puppies (n = 6). Immunoglobulin (IgA, IgE, IgG, IgG1, and IgG2a), parasite load (eggs in feces), number of expelled adults and eggs extracted from the female uterus, and their fertility percentages were analyzed. In mice, it was observed a highly significant reduction (73%) of tissue larvae, a mixed cytokine profile (Th1/Th2), and anti-T. canis antibody titers (IgG, IgG1, IgG2a) using rTVcan + QuialA® mix. In canines, rTVcan + QuialA® promoted reduction in the parasite eggs in feces (95%) and eggs reduction obtained from the uteri of pharmacologically expelled adult females (58.38%). In our knowledge this is the first canine clinical trial of a vaccine with T. canis recombinant proteins. The formulation used has been shown to efficiently stimulate the production of antibodies against infection by T. canis. In the canine, a significant reduction in the number of eggs expelled by the experimental animals that received the formulation prophylactically was evidenced. Future tests should be developed to evaluate the duration of the protective effect and analyze other immune pathways that could be stimulated by the formulation used.

Seroprevalence of exposure to SARS-CoV-2 in domestic dogs and cats and its relationship with COVID-19 cases in the city of Villavicencio, Colombia.

Background: Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak, different animal species have been implicated as possible intermediate hosts that could facilitate the transmission of the virus between species. The detection of these hosts has intensified, reporting wild, zoo, farm, and pet animals. The goal of this study was to determine the seroprevalence of anti-SARS-CoV-2 immunoglobulins (IgG) in domestic dogs and cats and its epidemiological association with the frequency of coronavirus disease 2019 (COVID-19) patients in Villavicencio, Colombia. Methods: 300 dogs and 135 cats were randomly selected in a two-stage distribution by clusters according to COVID-19 cases (positive RT-qPCR for SARS-CoV-2) within the human population distributed within the eight communes of Villavicencio. Indirect enzyme-linked immunosorbent assay (ELISA) technique was applied in order to determine anti-SARS-CoV-2 IgG in sera samples. Kernel density estimation was used to compare the prevalence of COVID-19 cases with the seropositivity of dogs and cats. Results: The overall seroprevalence of anti-SARS-CoV-2 IgG was 4.6% (95% CI=3.2-7.4). In canines, 3.67% (95% CI=2.1-6.4) and felines 6.67% (95% CI=3.6-12.18). Kernel density estimation indicated that seropositive cases were concentrated in the southwest region of the city. There was a positive association between SARS-CoV-2 seropositivity in pet animals and their habitat in Commune 2 (adjusted OR=5.84; 95% CI=1.1-30.88). Spearman's correlation coefficients were weakly positive ( p=0.32) between the ratio of COVID-19 cases in November 2020 and the results for domestic dogs and cats from the eight communes of Villavicencio. Conclusions: In the present research cats were more susceptible to SARS-CoV-2 infection than dogs. This study provides the first positive results of anti-SARS-CoV-2 ELISA serological tests in domestic dogs and cats in Colombia with information about the virus transmission dynamics in Latin America during the COVID-19 pandemic.

Seropositividad a Toxocara spp. en estudiantes atópicos de la Universidad de los Llanos / Seropositivity to Toxocara spp. in atopic students from Universidad de los Llanos / Soro positividade à Toxocara spp. em alunos atópicos da Universidade dos Llanos

Introducción: Las exposiciones frecuentes o estacionales a helmintos que no provocan infecciones crónicas se asocian a un aumento de la inflamación alérgica, situación que podría extrapolarse a la toxocariasis humana. El objetivo de esta investigación fue determinar la frecuencia de seropositivos a Toxocara spp. entre estudiantes atópicos y la relación entre atopia y seropositividad a Toxocara spp. Materiales y métodos: Estudio observacional transversal donde por conveniencia se seleccionaron 90 estudiantes de los programas de Enfermería, Regencia en Farmacia y MVZ de la Universidad de los Llanos que según diligenciamiento del cuestionario ISAAC fase III se presume sufren de enfermedad atópica; para desarrollar en ellos la prueba de hipersensibilización alérgica cutánea (PHAC), utilizando extractos de Blomia tropicalis y Dermatophagoides pteronyssius. En los estudiantes positivos a esta prueba, se tomaron muestras sanguíneas para el recuento de eosinófilos e inmunoensayo in-house para IgG anti-Toxocara spp. Resultados: De los 90 estudiantes con antecedentes de enfermedad atópica, solo el 33,3% fueron positivos para uno o ambos ácaros del polvo en la PHAC y su recuento de eosinófilos en sangre fue normal 66,6%, medio 26,7% y moderado 6,7%. La frecuencia de seropositividad a Toxocara spp. fue del 73,3% (DO 1,009 cut-off). La OR entre atopia y seropositividad a Toxocara spp. fue 1,18 (IC95% 0,24-5,7). Discusión: Colombia es uno de los países con alta endemicidad de toxocariasis con prevalencias entre 40.4­54.4%, dato confirmado según la frecuencia de seropositivos a Toxocara spp. encontrada en personas atópicas en estudio. Conclusiones: No se encontró relación entre atopia y seropositividad a Toxocara spp.

Introduction: The frequent or seasonal expositions to parasitic worms that do not provoke chronic infections are associated to an increase of allergic inflammation, situation that could be extrapolated to human toxocariasis. The objective of this research was to determine the frequency of Toxocara spp seropositivity among atopic students and the relationship be-tween atopy and seropositivity to Toxocara spp. Materials and methods: Observational and cross-sectional study using 90 students by convenience from the Nursing, Farmacy, Veter-inary, and Animal Science programs at the Universidad de los Llanos that according to the completion of the ISSAC phase III questionnaire are presumed to suffer from an atopic dis-ease. In order to perform an allergy skin test in them, extracts from Blomia tropicalis and Dermatophagoides pteronyssius were used. The students that tested positive got a blood test to count the eosinophils and the in-house enzyme immunoassay for IgG anti-Toxocara spp. Results: From the 90 students with records of atopic diseases, only 33,3% were positive to one or the two dust mites in the allergy skin test. Their eosinophils count in the blood test were normal 66.6%, medium 26.7% and moderate 6.7%. The frequency of seropositivity to Toxocara spp. was 73.3% (DO 1,009 cut-off). The OR between atopy and seropositivity to Toxocara spp. corresponded to 1.18 (CI 95% 0,24-5,7). Discussion: Colombia is one of the countries with high endemicity of toxocariasis with prevalences between 40.4­54.4%, a fact that is confirmed according to the frequency of seropositives to Toxocara spp. found in atopic people in the study. Conclusions: No relationship between atopy and seropositivity to Toxocara spp. was found

Introdução: as exposições frequentes ou estacionais a helmintos que não desenvolvem in-feções crônicas associam-se com o incremento de inflamação alérgica, situação que poderia evoluir a toxocaríase humana. O objetivo dessa pesquisa foi determinar a frequência de soro positividade à Toxocara spp. entre alunos atópicos e a relação entre atopia e soro positividade à Toxocara spp. Materiais e métodos: Estudo observacional transversal onde por conveniên-cia estudaram-se 90 alunos dos programas de enfermagem, regência em farmácia e medicina veterinária da Universidade dos Llanos que segundo o preenchimento do questionário ISAAC fase III presumiam padecer doença atópica. Para desenvolver a prova de hiper sensibilidade alérgica cutânea (PHAC), usaram-se extratos de Blomia tropicalis e Dermatophagoides pter-onyssius. Os alunos com teste positivo, foram analisados por meio de amostra sanguínea para contagem de eosinófilos e imunoensaio in-house para IgG anti-Toxocara spp. Resultados: dos 90 alunos analisados, só 33,3% foram positivos para um ou ambos ácaros no PHAC. A contagem de eosinófilos em sangue foi normal (66,6%), média (26,7%) e moderada (6,7%). A frequência de soro positividade para à Toxocara spp. foi de 73,3% (DO 1,009 cut-off). O OR relacionando atopia e soro positividade à Toxocara spp. foi de 1,18 (IC95% 0,24-5,7). Discussão: Colômbia é um dos países endêmicos para toxocaríase com prevalências entre 40.4 e 54,4%, informação confirmada com os achados desse estudo. Conclusões: Não foi encontrada relação estadística entre atopia e soro positividade à Toxocara spp

Immunogenicity and protection induced by recombinant Toxocara canis proteins in a murine model of toxocariasis.

Toxocariasis, a natural helminth infection of dogs and cats caused by Toxocara canis and T. cati, respectively, that are transmitted to mammals, including humans. Infection control is based currently on periodic antihelmintic treatment and there is a need for the development of vaccines to prevent this infection. MATERIALS AND METHODS: Eight potential vaccine candidate T. canis recombinant proteins were identified by in silico (rTcGPRs, rTcCad, rTcVcan, rTcCyst) and larval proteomics (rTES26, rTES32, rMUC-3 and rCTL-4) analyses. Immunogenicity and protection against infectious challenge for seven of these antigens were determined in a murine model of toxocariasis. C57BL/6 female mice were immunized with each of or combinations of recombinant antigens prior to challenge with 500 T. canis embryonated eggs. Levels of specific antibodies (IgG, IgG1, IgG2a and IgE) in sera and cytokines (IL-5, INF-É£ and IL-10) produced by antigens-stimulated splenocytes, were measured. Presence of specific antibodies to the molecules was measured in sera of T. canis-seropositive dogs and humans. RESULTS: All seven molecules were immunogenic in immunized mice; all stimulated significantly elevated levels of specific IgG, IgG1 or IgG2a and six were associated with elevated levels of specific IgE; all induced elevated production of IFN- É£ and IL-10 by splenocytes, but only the in silico-identified membrane-associated recombinants (rTcCad, rTcVcan, and rTcCyst) induced significantly increased IL-5 production. Vaccination with two of the latter (rTcCad and rTcVcan) reduced larval loads in the T. canis challenged mice by 54.3% and 53.9% (P < 0.0001), respectively, compared to unimmunized controls. All seven recombinants were recognized by T. canis-seropositive dog and human sera. CONCLUSION: The identification of vaccine targets by in silico analysis was an effective strategy to identify immunogenic T. canis proteins capable of reducing larval burdens following challenge with the parasite. Two recombinant proteins, rTcCad and rTcVcan, were identified as promising vaccine candidates for canine toxocariasis.

Estudio de la actividad acaricida in vitro del extracto acetónico de gliricidia sepium sobre Rhipicephalus microplus / Study of the in vitro acaricidal activity of gliricidia sepium acetone extract on Rhipicephalus microplus

La ganadería bovina es una actividad sobresaliente en el contexto económico nacional, generando el 3.5% del PIB nacional y el 56% del PIB pecuario; los ectoparásitos, específicamente la garrapata Rhipicephalus microplus, han sido asociados con grandes pérdidas económicas para este reglón productivo pecuario, desde sus efectos directos (estrés, anemia) hasta la posibilidad de ser vector de múltiples agentes etiológicos de enfermedades de importancia para la comercialización de los productos y subproductos animales. En la presente investigación se validó la información etnofarmacológica del uso del árbol matarratón (Gliricidia sepium) como antiparasitario externo en sistemas de producción bovina del trópico bajo. La marcha fitoquímica preliminar del extracto acetónico de G. sepium determinó la presencia de los grupos de metabolitos secundarios: flavonoides, terpenoides, cumarinas, glucósidos cardiotónicos, saponinas y taninos; hallados a través de las técnicas de cromatografía en capa delgada y colorimetría. La actividad acaricida del extracto acetónico de hojas de Gliricidia sepium se llevó a cabo en larvas y teleoginas de Rhipicephalus microplus, utilizando la prueba de inmersión de larvas (LIT) y la prueba de inmersión de adultos (AIT), respectivamente. El extracto acetónico de Gliricidia sepium mostró una CL50 de 78 mg/mL (71 ­ 83 mg/mL) y una CL90 de 146 mg/mL (128 ­ 182 mg/mL) en el bioensayo LIT. Por otro lado, la prueba AIT demuestra el efecto acaricida de G. sepium sobre teleoginas de R. microplus con una CL50 de 100 mg/mL (82 ­ 118 mg/mL) y una CL90 de 143 mg/mL (123 ­ 164 mg/mL). Así mismo, este estudio permitió establecer la inhibición de la ovoposición en un 56.7% de las teleoginas expuestas a la concentración de 100 mg/mL del extracto acetónico de G. sepium (p<0.05), además de un 100% en el control de reproducción y una eficiencia reproductiva del 0.0% para las teleoginas utilizadas dentro del estudio (p<0.01), expuestas a la misma concentración citada; todos los datos fueron organizados y procesados, utilizando el software OpenStat 4, de acuerdo a la prueba Probit para el cálculo de la concentración letal; las diferencias estadísticas citadas entre los niveles de tratamiento (extracto 5, 25, 50 y 100 mg/mL; control negativo -excipiente Tween 80 2.5% en agua destilada- y control positivo -Amitraz 0.025 mg/mL en agua destilada-) se obtuvieron a través de Chi-cuadrado para mortalidad y ANAVA de una vía, post hoc Tukey-Kramer, para índices reproductivos y afección de ciclo de vida de R. microplus. La anterior información es relevante para consolidar el cultivo del matarratón en los sistemas de producción bovino del piedemonte del departamento del Meta, con la finalidad de ser utilizada como método alternativo de control para la garrapata común del ganado, donde es evidente la necesidad de fortalecer los sistemas de producción animal con estrategias integradas para el control de parásitos a partir del uso de plantas medicinales promisorias del contexto.