Publications

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    ABSTRACT: Disease risk maps are important tools that help ascertain the likelihood of exposure to specific infectious agents. Understanding how climate change may affect the suitability of habitats for ticks will improve the accuracy of risk maps of tick-borne pathogen transmission in humans and domestic animal populations. Lyme disease (LD) is the most prevalent arthropod borne disease in the US and Europe. The bacterium Borrelia burgdorferi causes LD and it is transmitted to humans and other mammalian hosts through the bite of infected Ixodes ticks. LD risk maps in the transboundary region between the U.S. and Mexico are lacking. Moreover, none of the published studies that evaluated the effect of climate change in the spatial and temporal distribution of I. scapularis have focused on this region. The area of study included Texas and a portion of northeast Mexico. This area is referred herein as the Texas-Mexico transboundary region. Tick samples were obtained from various vertebrate hosts in the region under study. Ticks identified as I. scapularis were processed to obtain DNA and to determine if they were infected with B. burgdorferi using PCR. A maximum entropy approach (MAXENT) was used to forecast the present and future (2050) distribution of B. burgdorferi-infected I. scapularis in the Texas-Mexico transboundary region by correlating geographic data with climatic variables. Of the 1235 tick samples collected, 109 were identified as I. scapularis. Infection with B. burgdorferi was detected in 45% of the I. scapularis ticks collected. The model presented here indicates a wide distribution for I. scapularis, with higher probability of occurrence along the Gulf of Mexico coast. Results of the modeling approach applied predict that habitat suitable for the distribution of I. scapularis in the Texas-Mexico transboundary region will remain relatively stable until 2050. The Texas-Mexico transboundary region appears to be part of a continuum in the pathogenic landscape of LD. Forecasting based on climate trends provides a tool to adapt strategies in the near future to mitigate the impact of LD related to its distribution and risk for transmission to human populations in the Mexico-US transboundary region.
    Parasites & Vectors 04/2014; 7(1):199. · 3.25 Impact Factor
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    ABSTRACT: Ehrlichia canis is a rickettsial intracellular obligate bacterial pathogen and agent of canine monocytic ehrlichiosis. The prevalence of this disease in veterinary medicine can vary depending on the diagnostic method used and the geographic location. One hundred and fifty-two canine blood samples from six veterinary clinics and two shelters from Sinaloa State (Mexico) were analyzed in this study. All animals were suspected of having Canine Monocytic Ehrlichiosis (CME). The diagnostic methods used were the ELISA (Snap4Dx, IDEXX) together with blood smear and platelet count. From all dogs blood samples analyzed, 74.3% were positive to E. canis by ELISA and 40.1% were positive by blood smear. The sensitivity and specificity observed in the ELISA test were 78.8% and 86.7%. In addition, thrombocytopenia was presented in 87.6% of positive dogs. The predominant clinical manifestations observed were fever, anorexia, depression, lethargy, and petechiae. Consequently, this is the first report in which the morulae were visualized in the blood samples, and E. canis-specific antibodies were detected in dogs from Sinaloa, Northwest of Mexico.
    Journal of Veterinary Medicine. 10/2013; 2013.
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    ABSTRACT: Species distribution models were constructed for ten Ixodes species and Amblyomma cajennense for a region including Mexico and Texas. The model was based on a maximum entropy algorithm that used environmental layers to predict the relative probability of presence for each taxon. For Mexico, species geographic ranges were predicted by restricting the models to cells which have a higher probability than the lowest probability of the cells in which a presence record was located. There was spatial nonconcordance between the distributions of Amblyomma cajennense and the Ixodes group with the former restricted to lowlands and mainly the eastern coast of Mexico and the latter to montane regions with lower temperature. The risk of Lyme disease is, therefore, mainly present in the highlands where some Ixodes species are known vectors; if Amblyomma cajennense turns out to be a competent vector, the area of risk also extends to the lowlands and the east coast.
    Journal of Tropical Medicine 01/2012; 2012:959101.
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    Ma. Guadalupe Gordillo Pérez, Fortino Solórzano Santos
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    ABSTRACT: Lyme disease or Lyme borreliosis is an emerging infectious disease produced by Borrelia burgdorferi sensu lato, which is a bacteria transmitted to the host organism by the bite of Ixodes ticks. In this report we present the general knowledge about the etiological agent, clinical manifestations of the disease and diagnostic laboratory tests. We offer cumulative information about Lyme disease in Mexican children treated at two children's hospitals in Mexico City during the last 10 years.
    Boletín médico del Hospital Infantil de México. 04/2010; 67(2):164-176.
  • International Journal of Infectious Diseases - INT J INFECT DIS. 01/2010; 14.
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    ABSTRACT: Borrelia burgdorferisensu lato infection has been confirmed in clinical cases in the northeast of Mexico; however, the bacterium has not been identified as infecting the tick vector Ixodes, Amblyomma and Dermacentor ticks were collected from mammals and plants in northeastern Mexico and examined for Borrelia. Eighteen of 214 ticks were PCR-positive for the fla and 16S rRNA genes and 15 for the ospA gene. Southern blotting with a fla probe and sequencing of ospA genes confirmed infection with B. burgdorferi sensu stricto. These findings, together with reports of indigenous cases, fulfil the criteria that allow northeastern Mexico to be considered as a zone endemic for Lyme disease.
    Clinical Microbiology and Infection 06/2009; 15(5):496-8. · 4.58 Impact Factor
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    ABSTRACT: Four patients who had received tick bites while visiting forests in Mexico had skin lesions that met the case definition of erythema migrans, or borrelial lymphocytoma. Clinical diagnosis was supported with histologic, serologic, and molecular tests. This study suggests the Borrelia burgdorferi infection is in Mexico.
    Emerging Infectious Diseases 11/2007; 13(10):1556-8. · 6.79 Impact Factor
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    ABSTRACT: Objetivo. Investigar mediante métodos serológicos la infección por B burgdorferi en individuos del Distrito Federal y la zona noreste de México. Material y métodos. Se obtuvo una muestra representativa de sueros del Distrito Federal y la zona noreste de México, obtenidas en la Encuesta Seroepidemiológica Nacional de 1987-1988. Se detectaron anticuerpos IgG vs B burgdorferi por ELISA, confirmados con Western blot. En este trabajo se utilizó estadística descriptiva. Resultados. Fueron estudiados 2 346 sueros; 297 (12.6%) fueron positivos por inmunoensayo enzimático, y 122/297 fueron confirmados por Western blot. La seroprevalencia fue de 3.43% en el Distrito Federal y 6.2% en la zona noreste del país. Tamaulipas fue el estado con la seroprevalencia más alta. Conclusiones. La prevalencia de casos seropositivos sugieren que la infección por B burgdorferi ocurre en el noreste de México y el Distrito Federal. Es necesario identificar casos clínicos y buscar el vector infectado para confirmar la presencia de la enfermedad de Lyme en México. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.html
    Salud publica de Mexico 10/2003; · 0.94 Impact Factor
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    ABSTRACT: OBJETIVO: Investigar mediante métodos serológicos la infección por B burgdorferi en individuos del Distrito Federal y la zona noreste de México. MATERIAL Y MÉTODOS: Se obtuvo una muestra representativa de sueros del Distrito Federal y la zona noreste de México, obtenidas en la Encuesta Seroepidemiológica Nacional de 1987-1988. Se detectaron anticuerpos IgG vs B burgdorferi por ELISA, confirmados con Western blot. En este trabajo se utilizó estadística descriptiva. RESULTADOS: Fueron estudiados 2 346 sueros; 297 (12.6%) fueron positivos por inmunoensayo enzimático, y 122/297 fueron confirmados por Western blot. La seroprevalencia fue de 3.43% en el Distrito Federal y 6.2% en la zona noreste del país. Tamaulipas fue el estado con la seroprevalencia más alta. CONCLUSIONES: La prevalencia de casos seropositivos sugieren que la infección por B burgdorferi ocurre en el noreste de México y el Distrito Federal. Es necesario identificar casos clínicos y buscar el vector infectado para confirmar la presencia de la enfermedad de Lyme en México.
    Salud Pública de México. 01/2003;
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    ABSTRACT: Lyme disease is the most common vector-borne human disease in Europe and the United States. In Mexico, clinical cases suggestive of Lyme borreliosis have been reported; however, infection was not confirmed by serologic or microbiologic tests. To study the prevalence of IgG antibodies against Borrelia burgdorferi among Mexican persons, a community-based sero-survey including all states of Mexico was done. A sample of 2,890 sera representing individuals of all ages and all socioeconomic levels was studied. Antibodies anti-B. burgdorferi were determined by enzyme-linked immunosorbent assay (ELISA) using a whole-cell sonicated extract of B. burgdorferi strain B31. Serum specimens positive for ELISA were further studied by Western blot (WB). A serum sample was considered positive by WB if at least three of the following protein bands were recognized: 18, 24, 28, 29, 31, 34, 39, 41, 45, 58, 62, 66, and 93 kDa. Some WB positive specimens were further confirmed with an immunodot-blot (IDB) test using recombinant and purified B. burgdorferi proteins. Of the 2,890 specimens, 34 were positive for ELISA; nine of these 34 were confirmed as positive by WB. Four of the nine WB positive sera were tested by IDB and all four were positive. The prevalence of WB confirmed cases in the sample studied was 0.3%. Positive specimens were from residents of the northeastern and central areas of Mexico. The serological evidences of this study suggest that Borrelia burgdorferi infection is present in the Mexican population. This finding should be confirmed by documenting the infection in clinical cases and in tick vectors.
    Archives of Medical Research 01/1999; 30(1):64-8. · 2.08 Impact Factor
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    ABSTRACT: To analyze an outbreak of Serratia marcescens in a neonatal intensive care unit and identify the risk factors associated to the development of infection. It was a case-control study from March to July 1995. Factors included were age, sex, intravascular devices, nebulizers, mechanical ventilation, use of total parenteral nutrition (TPN), underlying diseases, surgical interventions, tubes, previous antimicrobial treatment and days of exposure. The associations were explored using the odds ratio. 24 cases and 30 controls were included. In the univariate analysis the significant risk factors (OR,IC) were use of central venous catheter (4.57, 1.01-23.5), days of use of TPN (4.38, 1.03-16.5), days of previous antimicrobial treatment (4.87, 1.60-22) and days of exposure (2.7, 2.65-27.6). In the multivariate analysis the significant risk factors were previous antimicrobial treatment (3.98, 2.36-18.2), days of previous antimicrobial treatment (6.76, 3.02-24.6) and days of use of TPN (4.87, 1.67-15.6). The significant risk factors in our study were previous antimicrobial treatment, days of antimicrobial and days of use of TPN.
    Revista de investigacion clinica; organo del Hospital de Enfermedades de la Nutricion 01/1998; 50(1):13-8. · 0.31 Impact Factor
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    ABSTRACT: To detect serological evidence of B burgdorferi infection in individuals from Mexico City and from the Northeast Region of the country. A representative sample size of serum from Mexico City and the states of the Northeast of Mexico were taken from serum samples corresponding to the 1987-1988 national survey were obtained from the National Serum Bank. Antibodies against B burgdorferi were detected by ELISA and confirmed with Western blot (WB) assays. Data were analyzed using descriptive statistics. A total of 2,346 serum samples were tested; 297 (12.6%) were positive for ELISA, and 122 of 297 were confirmed by WB. Seroprevalence was 3.43% in Mexico City and 6.2% in the Northeast region of the country. Tamaulipas was the state with the highest seroprevalence. The prevalence of seropositive cases shows that borrelial infection is present in the northeast of Mexico and Mexico City. Identification of clinical cases and infected tick vectors is necessary to confirm the presence of Lyme disease in Mexico.
    Salud publica de Mexico 45(5):351-5. · 0.94 Impact Factor

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