Outbreak of Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor strain--La Huasteca Region, Mexico, 2013.

On September 2 and 6, 2013, Mexico's National System of Epidemiological Surveillance identified two cases of cholera in Mexico City. Rectal swab cultures from both patients were confirmed as toxigenic Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. Pulsed-field gel electrophoresis and virulence gene amplification (ctxA, ctxB, zot, and ace) demonstrated that the strains were identical to one another but different from strains circulating in Mexico previously. The strains were indistinguishable from the strain that has caused outbreaks in Haiti, the Dominican Republic, and Cuba. The strain was susceptible to doxycycline, had intermediate susceptibility to ampicillin and chloramphenicol, was less than fully susceptible to ciprofloxacin, and was resistant to furazolidone and trimethoprim-sulfamethoxazole. An investigation failed to identify a common source of infection, additional cases, or any epidemiologic link between the cases. Both patients were treated with a single, 300-mg dose of doxycycline, and their symptoms resolved.

Influenza seasonality goes south in the Yucatan Peninsula: The case for a different influenza vaccine calendar in this Mexican region.

INTRODUCTION: While vaccination may be relatively straightforward for regions with a well-defined winter season, the situation is quite different for tropical regions. Influenza activity in tropical regions might be out of phase with the dynamics predicted for their hemispheric group thereby impacting the effectiveness of the immunization campaign. OBJECTIVE: To investigate how the climatic diversity of Mexico hinders its existing influenza immunization strategy and to suggest that the hemispheric vaccine recommendations be tailored to the regional level in order to optimize vaccine effectiveness. METHODS: We studied the seasonality of influenza throughoutMexico by modeling virological and mortality data.De-trended time series of each Mexican state were analyzed by Fourier decomposition to describe the amplitude and timing of annual influenza epidemic cycles and to compare with each the timing of the WHO's Northern and Southern Hemispheric vaccination schedule. FINDINGS: The timings of the primary (major) peaks of both virological and mortality data for most Mexican states are well aligned with the Northern Hemisphere winter (December-February) and vaccine schedule. However, influenza peaks in September in the three states of the Yucatan Peninsula. Influenza-related mortality also peaks in September in Quintana Roo and Yucatan whereas it peaks in May in Campeche. As the current timing of vaccination in Mexico is between October and November, more than half of the annual influenza cases have already occurred in the Yucatan Peninsula states by the time the Northern Hemispheric vaccine is delivered and administered. CONCLUSION: The current Northern Hemispheric influenza calendar adopted for Mexico is not optimal for the Yucatan Peninsula states thereby likely reducing the effectiveness of the immunization of the population. We recommend that Mexico tailor its immunization strategy to better reflect its climatologic and epidemiological diversity and adopt the WHO Southern Hemisphere influenza vaccine and schedule for the Yucatan Peninsula.

EV-D68 infection in children with asthma exacerbation and pneumonia in Mexico City during 2014 autumn.

BACKGROUND: Human enterovirus D68 (EV-D68) recently caused an increase in mild-to-severe pediatric respiratory cases in North America and some European countries. Even though few of these children presented with acute paralytic disease, direct causal relationship cannot yet be assumed. OBJECTIVES: The purposes of this report were to describe the clinical findings of an outbreak of EV-D68 infection in Mexico City and identify the genetic relationship with previously reported strains. PATIENTS/METHODS: Between September and December 2014, 126 nasopharyngeal samples (NPS) of hospitalized children <15 years of age with ARI were tested for the presence of respiratory viruses using a multiplex RT-qPCR and EV-D68-specific RT-qPCR. Clinical, epidemiological, and demographic data were collected and associated with symptomatology and viral infections. Phylogenetic analyses were performed using VP1 region. RESULTS: Enterovirus/rhinovirus infection was detected in 40 patients (31·7%), of which 24 patients were EV-D68-positive. EV-D68 infection prevailed over September and October 2014 and was associated with neutrophilia and lymphopenia, and patients were more likely to develop hypoxemia. Phylogenetic analyses showed that Mexican EV-D68 belongs to the new B1 clade. CONCLUSIONS: This is the first EV-D68 outbreak described in Mexico and occurred few weeks after the United States reported similar infections. Although EV-D68 belongs to new B1 clade, no neurological affection was observed.

Two Salmonella OmpC K(b)-restricted epitopes for CD8+-T-cell recognition.

We report the identification of two peptides from Salmonella OmpC porin that can bind to major histocompatibility complex class I K(b) molecules and are targets of cytotoxic T lymphocytes from Salmonella-infected mice. These peptides are conserved in gram-negative bacterial porins and are the first Salmonella porin-specific epitopes described for possible CD8(+)-T-cell elimination of infected cells.

Rubisco activase chaperone activity is regulated by a post-translational mechanism in maize leaves.

Rubisco activase (RCA) is a molecular chaperone present in maize as 43 kDa and 41 kDa polypeptides. They are encoded by two different genes comprising an identical ORF that corresponds to the 43 kDa RCA polypeptide, and their transcripts do not show putative splicing sites. To determine the origin of the 41 kDa polypeptide, leaf poly A(+) mRNA was in vitro translated. Results demonstrated de novo synthesis only for the 43 kDa RCA. Antibodies developed against peptides from either the carboxy- or the amino-terminal end of 43 kDa RCA showed by western blot that the 43 kDa polypeptide amino-terminal region is missing in the 41 kDa polypeptide, whereas both RCA polypeptides shared the carboxy-end region. Regulation of RCA polypeptide ratios was determined in plant leaves at different developmental stages and under stressing environmental conditions. Increased levels of 43/41 kDa RCA ratio were found in leaves under low light exposure, whereas this ratio declined under water stress. Measurements of chaperone activity either on each RCA polypeptide alone or in a mixture showed the functional relevance of different 43/41 kDa RCA polypeptide ratios. Greater chaperone activity was found for the 41 kDa than for the 43 kDa polypeptide. Taken together, these results indicate that 41 kDa RCA polypeptide formation is regulated by limited proteolysis of the 43 kDa RCA at its amino-terminal region. This pathway is sensitive to developmental and environmental signals, and seems to play a relevant function during plant stress.