Influenza-attributable burden in United Kingdom primary care.

Influenza is rarely laboratory-confirmed and the outpatient influenza burden is rarely studied due to a lack of suitable data. We used the Clinical Practice Research Datalink (CPRD) and surveillance data from Public Health England in a linear regression model to assess the number of persons consulting UK general practitioners (GP episodes) for respiratory illness, otitis media and antibiotic prescriptions attributable to influenza during 14 seasons, 1995-2009. In CPRD we ascertained influenza vaccination status in each season and risk status (conditions associated with severe influenza outcomes). Seasonal mean estimates of influenza-attributable GP episodes in the UK were 857 996 for respiratory disease including 68 777 for otitis media, with wide inter-seasonal variability. In an average season, 2·4%/0·5% of children aged <5 years and 1·3%/0·1% of seniors aged ⩾75 years had a GP episode for respiratory illness attributed to influenza A/B. Two-thirds of influenza-attributable GP episodes were estimated to result in prescription of antibiotics. These estimates are substantially greater than those derived from clinically reported influenza-like illness in surveillance programmes. Because health service costs of influenza are largely borne in general practice, these are important findings for cost-benefit assessment of influenza vaccination programmes.

Spatio-temporal patterns of diarrhoeal mortality in Mexico.

Diarrhoeal mortality rates in Mexican children dramatically declined during the 1980s and 1990s, concomitant with a temporal shift in peak deaths from summer to autumn-winter. The spatial dynamics of these patterns have not previously been studied. We first describe the seasonal features of paediatric diarrhoeal mortality in Mexico as a whole, then across individual states. While no geographical gradients in the magnitude of diarrhoeal mortality rates have been detected in recent years, we identified a distinct spatial pattern in the timing of peak mortality rate. In the 1980s the summer peak mortality was earliest around Mexico's capital and later in states to the southeast and northwest. Our results suggest that the direction and timing of those annual waves are related to the mean monthly precipitation and mean daily temperature. This pattern has disintegrated in recent years as the summer peak has diminished.

The 'ghosts' that pester studies on learning in mosquitoes: guidelines to chase them off.

The identification of memory and learning in medically important mosquito species has been of epidemiological interest mainly because of the implications of learning on the pattern of contact between vectors and hosts. Empirical results either showing or suggesting the existence of cognitive abilities in mosquitoes have been reported in a number of experimental studies, mainly based on the observation of individual fidelity towards subsets of specific resources, such as hosts, resting sites or breeding sites. A closer inspection of the design of these experiments shows that, with the exception of recent studies providing stronger evidence of learning in the genus Culex (Diptera: Culicidae), methodological shortcomings still hinder the possibility of eliminating alternative interpretations for these findings, in some cases because the experiments were not specifically designed to identify the phenomenon, but mostly because of a lack of appropriate controls or replication. By highlighting these limitations, while acknowledging the practical difficulties that are inherent to the field, we aim to help expel from future research the 'ghosts' that still preclude the achievement of more definite conclusions about the prevalence of memory and learning in this group of insects.