Population‐based surveillance for 2009 pandemic influenza A (H1N1) virus in Guatemala, 2009

Please cite this paper as: Reyes et al. (2010) Population‐based surveillance for 2009 pandemic influenza A (H1N1) virus in Guatemala, 2009. Influenza and Other Respiratory Viruses 4(3), 129–140. Background  In April 2009, 2009 pandemic influenza A H1N1 (2009 H1N1) was first identified in Mexico but did not cause widespread transmission in neighboring Guatemala until several weeks later. Methodology and principle findings  Using a population‐based surveillance system for hospitalized pneumonia and influenza‐like illness ongoing before the 2009 H1N1 pandemic began, we tracked the onset of 2009 H1N1 infection in Guatemala. We identified 239 individuals infected with influenza A (2009 H1N1) between May and December 2009, of whom 76 were hospitalized with pneumonia and 11 died (case fatality proportion: 4·6%, 95% confidence interval [CI] 2·3–8·1%). The median age of patients infected with 2009 H1N1 was 8·8 years, the median age of those hospitalized with pneumonia was 4·2 years, and five (45·5%) deaths occurred in children <5 years old. Crude rates of hospitalization between May and December 2009 were highest for children <5 years old. Twenty‐one (27·6%) of the patients hospitalized with 2009 H1N1 were admitted to the intensive care unit and eight (10·5%) required mechanical ventilation. Underlying chronic conditions were noted in 14 (18·4%) of patients with pneumonia hospitalized with 2009 H1N1 infection. Conclusions and significance  Chronic illnesses may be underdiagnosed in Guatemala, making it difficult to identify this risk group for vaccination. Children 6 months to 5 years old should be among priority groups for vaccination to prevent serious consequences because of 2009 H1N1 infection.     

On the nature of tetraalkylammonium ions in common electrochemical solvents: General and specific solvation – Quantitative aspects

The free energies of each of 80 tetraalkylammonium ion/solvent complexes [R₄N⁺/(solv)_n], with R ranging from methyl through butyl and n ranging from 1 through 4, were computed by density functional theory (DFT) in five common electrochemical solvents: dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetonitrile (AN), dichloromethane (DCM), and methanol (MeOH). The energies of the complexes were computed both with and without their solvation energies. Additional computations of the energies of the individual components, both solvated and unsolvated, were also carried out. The resulting data permit construction of a thermodynamic cycle for each R₄N⁺/solvent pair that in turn allows the determination of the extent of general and specific solvation energies for that pair. An additional series of computations for pentane as solvent were carried out. Since this solvent should not coordinate with tetraalkylammonium ions, these computations provide a test of the validity of the computational method. This work represents a useful new general protocol for assessing the relative importance of general and specific solvation in chemical systems.