Search

The emergence of the Omicron variant has generated concerns about the efficacy of COVID-19 vaccines. We evaluated the serum neutralizing activity of antibodies against the Omicron (lineage BA.1.1) by plaque reduction neutralizing test, as well as its correlation with age and gender, in a Colombian cohort six months after being vaccinated with BNT162b2 (Pfizer/BioNTech). Compared to all other variants analyzed, a significantly lower neutralizing activity (p<0.001) was observed against Omicron. Interestingly, older individuals exhibited lower titers against Omicron than those younger than 40. No statistical differences in neutralizing activity were observed according to gender. Our results showed that two doses of BNT162b2 might not provide robust protection against the Omicron variant over time. It is necessary to consider including changes in the composition of the vaccines to protect against new emerging variants of SARS-CoV-2 and campaigns to implement additional booster vaccinations. [ABSTRACT FROM AUTHOR]

The emergence of theOmicron variant has generated concerns about the efficacy of COVID-19 vaccines. We evaluated the serum neutralizing activity of antibodies against the Omicron (lineage BA.1.1) by plaque reduction neutralizing test, aswell as its correlation with age and gender, in a Colombian cohort six months after being vaccinated with BNT162b2 (Pfizer/BioNTech). Compared to all other variants analyzed, a significantly lower neutralizing activity (p<0.001) was observed against Omicron. Interestingly, older individuals exhibited lower titers againstOmicron than those younger than 40. No statistical differences in neutralizing activity were observed according to gender. Our results showed that two doses of BNT162b2 might not provide robust protection against the Omicron variant over time. It is necessary to consider including changes in the composition of the vaccines to protect against new emerging variants of SARS-CoV-2 and campaigns to implement additional booster vaccinations. [ABSTRACT FROM AUTHOR]

Background: Rickettsia felis is an emergent Rickettsial agent whose main vector is Ctenocephalides felis, but ticks, mites and lice are also infected. We aimed to search for molecular evidence of Rickettsia spp. in fleas collected from dogs and wild rodents (Heteromys anomalous) from three villages of Córdoba and Antioquia provinces (Northern of Colombia), where outbreaks of rickettsioses have occurred, and discuss the possible role of fleas on endemic/enzootic regions for rickettsia. Methods: During 2010 and 2012, 649 Ctenocephalides felis felis and 24 Pulex irritans fleas were removed from dogs and wild rodents (Heteromys anomalous), respectively, in 3 locations from Córdoba and Antioquia provinces (Colombia). These fleas were tested into pools for Rickettsial infection by PCR, targeting gltA, ompB, and ompA Rickettsial genes. Results: Almost 20% (30/153) of C. felis felis pools contained Rickettsial DNA. The fragments of ompB gene showed high identity values between sequences from Necocli and Los Cordobas with R. felis strain from Senegal (100% and 99.7% respectively) and all were highly related by phylogenetic analyses. Rickettsial DNA in pools of P. irritans was not detected. Conclusion: Our findings highlighted the endemicity of the infection by R. felis in fleas from northern of Colombia and showed the likely importance of dogs as hosts of C. felis felis fleas and their potential role as reservoirs of R. felis. [ABSTRACT FROM AUTHOR]

Due to its tropical location, chains of mountains, inter-Andean valleys, Amazon basin area, eastern plains and shores on both the Atlantic and Pacific Oceans, Colombia has many ecosystems and the second largest plant biodiversity in the world. Many plant species, both native and naturalized, are currently recognized as toxic for both animals and humans, and some of them are known to cause their toxic effects due to their alkaloid content. Among these, there are plants containing the hepatotoxic pyrrolizidine alkaloids, neurotoxins such as the indolizidine alkaloid swainsonine and the piperidine alkaloids coniine and γ-coniceine and tropane alkaloids. Unfortunately, the research in toxic plants in Colombia is not nearly proportional to its plant biodiversity and the scientific information available is only very scarce. The present review aims at summarizing the scarce information about plant alkaloid toxicosis in animals and humans in Colombia. [ABSTRACT FROM AUTHOR]

Chronic exposure to aflatoxins, and especially to aflatoxin B1(AFB1), causes hepatocellular carcinoma with prevalence 16–32 times higher in developing compared with developed countries. Aflatoxin M1(AFM1) is a monohydroxylated metabolite from AFB1 that is secreted in milk and which can be used as a biomarker of AFB1 exposure. This study aimed to determine AFM1 levels in human breast milk using immunoaffinity column clean-up with HPLC and fluorescence detection. Breast milk samples were obtained from 50 nursing mothers. Volunteers filled in a questionnaire giving their consent to analyse their samples as well as details of their socioeconomic, demographic and clinical data. The possible dietary sources of aflatoxins were assessed using a food frequency questionnaire. A total of 90% of the samples tested positive for AFM1, with a mean of 5.2 ng l−1and a range of 0.9–18.5 ng l−1. The study demonstrated a high frequency of exposure of mothers and neonates to AFB1 and AFM1 in Colombia, and it points out the need to regulate and monitor continuously the presence of aflatoxins in human foods. Further research is needed in order to determine the presence of other mycotoxins in foods and in human samples as well as to devise protection strategies in a country where mycotoxins in human foods are commonly found. [ABSTRACT FROM PUBLISHER]

One of the main characteristics of the human immunodeficiency virus is its genetic variability and rapid adaptation to changing environmental conditions. This variability, resulting from the lack of proofreading activity of the viral reverse transcriptase, generates mutations that could be fixed either by random genetic drift or by positive selection. Among the forces driving positive selection are antiretroviral therapy and CD8+ T-cells, the most important immune mechanism involved in viral control. Here, we describe mutations induced by these selective forces acting on the pol gene of HIV in a group of infected individuals. We used Maximum Likelihood analyses of the ratio of non-synonymous to synonymous mutations per site (dN/dS) to study the extent of positive selection in the protease and the reverse transcriptase, using 614 viral sequences from Colombian patients. We also performed computational approaches, docking and algorithmic analyses, to assess whether the positively selected mutations affected binding to the HLA molecules. We found 19 positively-selected codons in drug resistance-associated sites and 22 located within CD8+ T-cell epitopes. A high percentage of mutations in these epitopes has not been previously reported. According to the docking analyses only one of those mutations affected HLA binding. However, algorithmic methods predicted a decrease in the affinity for the HLA molecule in seven mutated peptides. The bioinformatics strategies described here are useful to identify putative positively selected mutations associated with immune escape but should be complemented with an experimental approach to define the impact of these mutations on the functional profile of the CD8+ T-cells. [ABSTRACT FROM AUTHOR]

A dengue fever surveillance study was conducted at three medical facilities located in the low-income district of San Javier in Medellin, Colombia. During March 2008 to 2009, 781 patients with fever regardless of chief complaint were recruited for acute dengue virus infection testing. Of the 781 tested, 73 (9.3%) were positive for dengue infection. Serotypes DENV-2 (77%) and -3 (23%) were detected by PCR. One patient met the diagnostic criteria for dengue hemorrhagic fever. Only 3 out of 73 (4.1%) febrile subjects testing positive for dengue infection were diagnosed with dengue fever by the treating physician. This study confirms dengue virus as an important cause of acute febrile illness in Medellin, Colombia, but it is difficult to diagnose without dengue diagnostic testing. [ABSTRACT FROM AUTHOR]

Résumé: Objectifs: Déterminer les facteurs influençant l’âge de début de la polyarthrite rhumatoïde (PR). Méthodes: Nous avons étudié un échantillon de 152 patients colombiens atteints de PR. Les rapports des risques instantanés (hazard ratio [HR]), qui mesurent l’effet taille des facteurs de risque sur l’âge de survenue de la PR ont été calculés en utilisant des modèles de régression de Cox. Résultats: La présence d’anticorps anti-CCP était associée avec une augmentation du risque de survenue d’un début précoce de la PR (HR=1,60 ; IC95 % : 1,06–2,40). À l’inverse, la présence de la séquence protectrice 70DERAA74 était associée à un âge de début plus tardif de la PR (HR=0,55 ; IC95 % : 0,33–0,92). Après ajustement pour les anti-CCP et la séquence 70DERAA74, les variables suivantes n’avaient pas d’influence significative sur l’âge de début de la PR : sexe, tabagisme, antécédent familial de PR, polymorphisme du gène TNF-308 A, épitope HLA partagé, présence du facteur rhumatoïde. Conclusion: Les anticorps anti-CCP et la séquence 70DERAA74 de HLA-DRB1 influencent l’âge de début de la PR. [ABSTRACT FROM AUTHOR]

A study was conducted to establish the occurrence and levels of contamination of aflatoxin M 1 (AFM1) in retail milk from Bogotá, Colombia. A total of 241 samples were analysed during 2004 and 2005. Samples were cleaned up by an immunoaffinity column and AFM1 was quantified by liquid chromatography with fluorescence detection. A total of 69.2 and 79.4% of the samples analysed during 2004 and 2005, respectively, were found to contain levels of AFM1 above 10&ThickSpace;ng&ThickSpace;l -1 . Levels of contamination ranged from 10.7 to 213.0&ThickSpace;ng&ThickSpace;l -1 in 2004, and from 10.6 to 288.9&ThickSpace;ng&ThickSpace;l -1 in 2005. Despite the high incidence of AFM1 found in the milk samples analysed, all samples complied with current local regulations, which allow AFM1 content in milk up to 400&ThickSpace;ng&ThickSpace;l -1 . However, due to the high incidence of AFM1 in milk found in the present study, it is recommended that a permanent surveillance programme be established for milk consumed in Bogotá in order to prevent milk lots containing&ThickSpace;levels above the regulatory level entering the food chain. [ABSTRACT FROM AUTHOR]

Canine distemper virus (CDV) is considered a reemerging disease-causing agent in domestic dogs because it presents high divergence among circulating strains worldwide. In Colombia, the South America-3 and South America/North America-4 lineages co-circulate in domestic dogs, both in the Medellin metropolitan area. In this paper, two full CDV genomes from each viral lineage circulating in Medellin were sequenced; we explored the phylogenetic relationship with the available genome sequences; we described the presence of CDV mutations in the South America-3 and South America/North America-4 lineages associated with adaptation to human cells and a crossing of the species barrier and pathogenicity; and we established the evolutionary rates and time of the closest common ancestor for each gene and characterized the presentation of multiple genomic sites by positive selection. [ABSTRACT FROM AUTHOR]

Abstract: When comparing current smoking in schizophrenia patients versus the general population, the average odds ratio (OR) was 5.3 in a meta-analysis of 42 studies from 20 nations. Limited tobacco access can eliminate this strong association in some nations. Out of the 42 ORs, 37 were significantly higher than 1. Of the 5 non-significant ORs, three came from Colombian studies comparing current smoking prevalences in schizophrenia versus those in the general population (18%). However, the 3 ORs were not adjusted for confounders. We hypothesized that the association between schizophrenia and smoking is so strong that it can be detected in populations with limited access to smoking after carefully controlling for confounders. Of the three Colombian studies, one included 73 schizophrenia patients (DSM-IV schizophrenia or schizoaffective disorder) and 111 patients with mood disorders (DSM-IV bipolar or major depressive disorders). The current study matched each of these patients with 2 controls from the general population and performed more sophisticated statistical analyses. Prevalences of current smoking were 26% for schizophrenia patients and 10% for their matched controls (adjusted Mantel–Haenszel OR=3.1, 95% CI, 1.4–6.8), and 7% for patients with mood disorders and 12% for their matched controls (adjusted Mantel–Haenszel OR=0.62; CI, 0.28–1.4). The previously observed lack of association between schizophrenia and current smoking was due to lack of control of important confounding variables because of the absence of a control group. This re-analysis, which used a careful matching that controlled for confounders, suggests that the association between schizophrenia and smoking behaviors can stand in populations with low monetary income and low smoking rates. This study also suggests that the association between severe mood disorders (bipolar and major depression) and smoking is not as strong as that observed between schizophrenia and smoking, and may not be observable in countries where people have limited economic resources. [Copyright &y& Elsevier]