Leptospirosis Prevalence in a Population of Yucatan, Mexico

Objective. To measure the prevalence of leptospirosis with two techniques in inhabitants of Izamal, Yucatan and to determine its relation with some exposure factors. Material and Methods. Transversal study in populations belonging to the HR62—IMSS-Opportunities working force in Izamal, Yucatan. Population, including 6 years of age or more, was randomly selected to participate in the study. A questionnaire was applied for personal ID and exposure factors; blood samples were taken for leptospirosis diagnosis. Simple frequencies, proportions, tendency and dispersion measures, prevalence and odd ratios and confidence intervals (CI) of 95%, and logistic regression model were obtained. Results. 204 patients, between 9 and 80 years old were included; 180 were positive (88.2%) with the dark-field technique; using MAT cutoff at 1 : 40, 178 patients (87.3%) were positive, while at 1 : 80 there were 103 positive (50.5%). The predominant serovar was Hardjo (94%). The highest prevalence was in women (96.3%) and in the >45-year-old group (95.7%); feminine gender (RM = 2.31 IC 95% 3.59–28.6), housewife (RM = 22.8 IC 95% 4.9–106.1), being in contact with stagnant water (RM = 5.2 IC 95% 1.7–15.9), and being in contact with domestic animal feces (RM = 5.1 IC 95% 1.9–13.1), these being the most significant variables in the final logistic regression model. Conclusions. The prevalence found was higher than the one nationally and internationally reported, representing an important finding, being in turn a local public health, maybe nationally. It is urgent to reinforce this research as well as to establish preventive and control measure to avoid exposure and health damages

Specific genetic markers for detecting subtypes of dengue virus serotype-2 in isolates from the states of Oaxaca and Veracruz, Mexico

<p>Abstract</p> <p>Background</p> <p>Dengue (DEN) is an infectious disease caused by the DEN virus (DENV), which belongs to the <it>Flavivirus </it>genus in the family <it>Flaviviridae</it>. It has a (+) sense RNA genome and is mainly transmitted to humans by the vector mosquito <it>Aedes aegypti</it>. Dengue fever (DF) and dengue hemorrhagic fever (DHF) are caused by one of four closely related virus serotypes (DENV-1, DENV-2, DENV-3 and DENV-4). Epidemiological and evolutionary studies have indicated that host and viral factors are involved in determining disease outcome and have proved the importance of viral genotype in causing severe epidemics. Host immune status and mosquito vectorial capacity are also important influences on the severity of infection. Therefore, an understanding of the relationship between virus variants with altered amino acids and high pathogenicity will provide more information on the molecular epidemiology of DEN. Accordingly, knowledge of the DENV serotypes and genotypes circulating in the latest DEN outbreaks around the world, including Mexico, will contribute to understanding DEN infections.</p> <p>Results</p> <p>1. We obtained 88 isolates of DENV, 27 from Oaxaca and 61 from Veracruz. 2. Of these 88 isolates, 16 were serotype 1; 62 serotype 2; 7 serotype 3; and 2 serotype 4. One isolate had 2 serotypes (DENV-2 and -1). 3. Partial nucleotide sequences of the genes encoding C- prM (14 sequences), the NS3 helicase domain (7 sequences), the NS5 S-adenosyl methionine transferase domain (7 sequences) and the RNA-dependent RNA polymerase (RdRp) domain (18 sequences) were obtained. Phylogenetic analysis showed that DENV-2 isolates belonged to the Asian/American genotype. In addition, the Asian/American genotype was divided into two clusters, one containing the isolates from 2001 and the other the isolates from 2005–2006 with high bootstrap support of 94%.</p> <p>Conclusion</p> <p>DENV-2 was the predominant serotype in the DF and DHF outbreak from 2005 to 2006 in Oaxaca State as well as in the 2006 outbreak in Veracruz State, with the Asian/American genotype prevalent in both states. Interestingly, DENV-1 and DENV-2 were the only serotypes related to DHF cases. In contrast, DENV-3 and DENV-4 were poorly represented according to epidemiological data reported in Mexico. We found that isoleucine was replaced by valine at residue 106 of protein C in the isolates from these 2005–2006 outbreaks and in those from the 1997, 1998 and 2001 outbreaks in the Caribbean islands. We suggested that this amino acid change may be used as a signature for isolates arising in the Caribbean islands and pertaining to the Asian/American genotype. Other amino acid changes are specific for the Asian/American, Asian and American strains.</p

A DNA Microarray-Based Assay to Detect Dual Infection with Two Dengue Virus Serotypes

Here; we have described and tested a microarray based-method for the screening of dengue virus (DENV) serotypes. This DNA microarray assay is specific and sensitive and can detect dual infections with two dengue virus serotypes and single-serotype infections. Other methodologies may underestimate samples containing more than one serotype. This technology can be used to discriminate between the four DENV serotypes. Single-stranded DNA targets were covalently attached to glass slides and hybridised with specific labelled probes. DENV isolates and dengue samples were used to evaluate microarray performance. Our results demonstrate that the probes hybridized specifically to DENV serotypes; with no detection of unspecific signals. This finding provides evidence that specific probes can effectively identify single and double infections in DENV samples

Epidemiological implications of the genetic diversification of dengue virus (DENV) serotypes and genotypes in Mexico

Variation and clade shifts in dengue virus (DENV) genotypes are responsible for numerous dengue fever outbreaks throughout Latin America in the past decade. Molecular analyses of dengue serotypes have revealed extensive genetic diversification and the emergence of new genotypes in Brazil (DENV-4 genotype I) and elsewhere in tropical and subtropical America. The goal of the present study is to assess the extent to which the adventitious introduction of DENV genotypes and their increasing genetic diversity affects dengue epidemiology in Mexico. A nuanced sequence inspection and phylogenetic analysis of the C-prM nucleotide region of DENV was performed for specimens collecting in 2009 from the Veracruz State, Mexico. Findings were contrasted with specimens collected in adjacent years and analysed based on the epidemiological patterns reported between 1990 and 2019. Additionally, the identification process of various DENV genotypes was assessed, including: (1) DENV-1, genotype V, (2) the DENV-2 Asian/American and Asian II genotypes (3) DENV-3, genotype III, and (4) DENV-4, genotype I. This resulted in the discovery of a distinct genetic cladistic pattern for serotype DENV-2. Lastly, study findings suggest that a correlation exists between the emergence of novel genotypes and genetic diversification, with the increasing incidence of DENV infections in Mexico in 2009

Dataset on the epidemiology and genetic diversification of dengue virus (DENV) serotypes and genotypes in Mexico

This work is licensed under a Creative Commons Attribution 4.0 International License.Dengue virus (DENV) evolution has had a significant impact on disease pathogenesis, virulence, and epidemiology in Mexico. Novel genotypic variation in DENV serotypes and genotypes may influence the magnitude and severity of dengue epidemics, as evidenced by 2009 data from Veracruz State. The data presented herein is related to the publication entitled “Epidemiological Implications of the Genetic Diversification of Dengue Virus (DENV) Serotypes and Genotypes in Mexico” [1]. Raw data and trees provide epidemiological data on DENV prevalence and a comprehensive phylogeny of both representative sequences collected from an NCBI repository, and 28 additional isolates from acute-phase plasma samples diagnosed with dengue fever or severe dengue (Raw sequencing data is hosted in the public repository Mendeley Data (http://dx.doi.org/10.17632/bf2kdhhf6x.2). Phylogenetic trees for each DENV serotype (DENV-1, -2, -3 and -4) were constructed using these sequences by a maximum likelihood methodology as well as a Bayesian Markov chain Monte Carlo (MCMC) integration approach. Phylogenetic trees exhibited: (1) DENV-1, genotype V, (2) the DENV-2 Asian/American and Asian II genotypes, (3) DENV-3, genotype III, and (4) DENV-4, genotype I. This data can be beneficial for future analyses on DENV serotype and genotype structure and the introduction of novel DENV genotype sequences in the Americas, for the further elucidation of dengue etiology.Consejo Nacional de Ciencia y Tecnología, Mexico EHG (Registration Number: 111110038; CVU: 49406)ED-de-la-C CONACYT Registration Number: 280838; CVU: 485179COMECYT Scholarship Number: 18BTD002

Clinical profile of dengue hemorrhagic fever cases in Mexico

Objetivo. El dengue hemorrágico en México es una enfermedad emergente desde 1994. La circulación de los cuatro serotipos incrementa el riesgo de epidemias de dengue hemorrágico. Material y métodos. Se reportan los datos clínicos y epidemiológicos de los casos de dengue hemorrágico confirmados y notificados por el IMSS de 1995 a 2003. Se analizaron las características clínicas y epidemiológicas entre grupos. Para el control y la evaluación final de las variables se utilizó un modelo multivariado. Resultados. Los casos fueron asignados en dos grupos: 438 con dengue clásico, que incluye 109 casos con manifestaciones hemorrágicas sin trombocitopenia, y 977 casos de dengue hemorrágico con 79 defunciones. Los factores de riesgo asociados a las defunciones fueron: hematemesis (RR 2.6; IC 95% 1.4-4.6) y melena (RR 2.2; IC 95% 1.2-3.7). Conclusiones. El cuadro clínico descrito para la población del Instituto Mexicano del Seguro Social permite identificar factores pronósticos que ayuden al clínico a prevenir y manejar adecuadamente los casos severos de dengue hemorrágico

Prevalencia de anticuerpos contra dengue y leptospira en la población de Jáltipan, Veracruz

Objetivo. Conocer la prevalencia de anticuerpos contra dengue y leptospira en Jáltipan, Veracruz, México. Material y métodos. Estudio transversal en 500 habitantes de Jáltipan, Veracruz, mediante un muestreo por hogares, aplicación de cuestionario y toma de muestras sanguíneas. Se buscaron anticuerpos IgG y se evaluaron factores asociados a sus seroprevalencias mediante regresión logística. Resultados. La seroprevalencia global para dengue virus fue 79.6% (IC95% 76-81); los principales factores vinculados con la infección fueron la edad (p< 0.001) y presencia de larvas en el domicilio (RMP= 2.94; IC95% 1.46-6.1). La seroprevalencia global contra leptospira fue 4% (IC95% 2-6). La mayor prevalencia fue para el grupo en edad productiva (35%, IC95%15-59). Quienes refirieron convivir simultáneamente con perros, cerdos, vacas y ratas presentaron una seroprevalencia de 25% (IC95% 0.63-80). El 85% de los positivos a leptospira también fue positivo a dengue. Conclusiones. La prevalencia de anticuerpos contra dengue virus demuestra el riesgo de brotes explosivos de dengue hemorrágico. Aunque la prevalecía de leptospirosis fue baja, se confirmó la coexistencia de estos agentes

Prevalencia de anticuerpos contra dengue y leptospira en la población de Jáltipan, Veracruz Prevalence of dengue and leptospira antibodies in the state of Veracruz, Mexico

OBJETIVO: Conocer la prevalencia de anticuerpos contra dengue y leptospira en Jáltipan, Veracruz, México MATERIAL Y MÉTODOS: Estudio transversal en 500 habitantes de Jáltipan, Veracruz, mediante un muestreo por hogares, aplicación de cuestionario y toma de muestras sanguíneas. Se buscaron anticuerpos IgG y se evaluaron factores asociados a sus seroprevalencias mediante regresión logística RESULTADOS: La seroprevalencia global para denguevirus fue 79.6% (IC95% 76-81); los principales factores vinculados con la infección fueron la edad (pOBJECTIVE: To discover the prevalence of antibodies against denguevirus and leptospira. MATERIAL AND METHODS: A cross-sectional study was carried out in 500 inhabitants of Veracruz, Mexico through household sampling, administration of a questionnaire and collection of blood samples. The presence of IgG antibodies was determined and factors associated with seroprevalence were evaluated using a logistic regression model. RESULTS: Total denguevirus seroprevalence was 79.6% (IC95% 76-81). The main factors associated with infection were age and residence in neighborhoods with higher vectorial indices (RMP=2.94, IC95% 1.46-6.1). Overall seroprevalence against leptospira was 4% (IC95% 2-6). Prevalence was higher in the 25 to 44 years age group (35%, IC95% 15-59). Seroprevalence in individuals who referred to living with dogs, pigs, cows and rats was 25% (IC95% 0.63-80). Eighty-five percent of individuals who were leptospira positive were also dengue positive. CONCLUSIONS: The prevalence of denguevirus antibodies suggests the risk of serious dengue hemorrhagic outbreaks. Although leptospirosis prevalence was low, the coexistence of both agents was confirmed

Clinical expression of dengue in beneficiaries of the Instituto Mexicano del Seguro Social in Veracruz, Mexico

Objective: To describe and compare the clinical behavior of Dengue Fever (DF) and Hemorrhagic Dengue Fever (HDF) in beneficiaries of the Instituto Mexicano del Seguro Social (IMSS). Methods: Transversal study in beneficiaries from Veracruz, selected among those who sought attention at two medical attention units, with probable dengue diagnosis. Surveys were performed to know personal and epidemiological data, as well as a clinical follow up. Blood samples were taken for RT-PCR viral identification and antibodies against Dengue. In the same way, platelet, hemoglobin, and hematocrit tests were performed for their determination. The SPSS 12.0 software was used for the process and analysis of the information, and simple frequencies, proportions, and means were estimated. Results: 109 patients were studied, classified as 72 DF and 37 as HDF. 40 isolations were performed, and the circulation of the four types of dengue virus was identified, although most of the isolations corresponded to serotype 2 (Asian-American genotype). In one patient, a simultaneous infection of dengue viruses 1 and 2 was identified. A group of patients did not present hemorrhages, capillary fragility, or liquid permeation, but with important thrombocytopenia and hemoconcentration, all infected with den-1 and den-2. Conclusions: The presence of cases with atipical behavior of the diseases were identified. The characteristics and immunologic experience of the populations, as well as the simultaneous circulation of various dengue viruses and their changing structure could be related with the current clinical behavior of Dengue in Mexico. It is important to continue the research to confirm these asseverations