A large effective population size for established within-host influenza virus infection

Strains of the influenza virus form coherent global populations, yet exist at the level of single infections in individual hosts. The relationship between these scales is a critical topic for understanding viral evolution. Here we investigate the within-host relationship between selection and the stochastic effects of genetic drift, estimating an effective population size of infection Ne for influenza infection. Examining whole-genome sequence data describing a chronic case of influenza B in a severely immunocompromised child we infer an Ne of 2.5 × 107 (95% confidence range 1.0 × 107 to 9.0 × 107) suggesting that genetic drift is of minimal importance during an established influenza infection. Our result, supported by data from influenza A infection, suggests that positive selection during within-host infection is primarily limited by the typically short period of infection. Atypically long infections may have a disproportionate influence upon global patterns of viral evolution

Inferring transmission bottleneck size from viral sequence data using a novel haplotype reconstruction method

The transmission bottleneck is defined as the number of viral particles that transmit from one host to establish an infection in another. Genome sequence data have been used to evaluate the size of the transmission bottleneck between humans infected with the influenza virus; however, the methods used to make these estimates have some limitations. Specifically, viral allele frequencies, which form the basis of many calculations, may not fully capture a process which involves the transmission of entire viral genomes. Here, we set out a novel approach for inferring viral transmission bottlenecks; our method combines an algorithm for haplotype reconstruction with maximum likelihood methods for bottleneck inference. This approach allows for rapid calculation and performs well when applied to data from simulated transmission events; errors in the haplotype reconstruction step did not adversely affect inferences of the population bottleneck. Applied to data from a previous household transmission study of influenza A infection, we confirm the result that the majority of transmission events involve a small number of viruses, albeit with slightly looser bottlenecks being inferred, with between 1 and 13 particles transmitted in the majority of cases. While influenza A transmission involves a tight population bottleneck, the bottleneck is not so tight as to universally prevent the transmission of within-host viral diversity

The challenge of leadership: ethnicity and gender among school leaders in England, Malaysia and Pakistan

Although women hold leadership positions in professional organisations, little attention has been paid to the experiences of women leaders other than middle- or upper-class white females. This chapter therefore explores - through narrative inquiries - the leadership experiences of nine black, minority ethnic and Muslim women principals in England, Malaysia and Pakistan. Whilst the notion of diversity is unpacked through the intersections of gender, race and cultural differences in three different education contexts within Western and Asian societies, the findings suggest that leadership experiences are influenced by cultural and racial norms, and gender did not favour women in their leadership pathway. This research paper contributes to the discussions about de-marginalising the leadership challenge from the eyes of whiteness. This study has the potential to fill in the knowledge gap in the female leadership domain from a cross-cultural context, while future directions for research are suggested