A two-locus gene conversion model with selection is developed. Under the joint action of selection, mutation, gene conversion, recombination, and random genetic drift, approximate formulas for the expectations of the moments of allele frequencies and the expected amounts of variation within and between two loci are obtained by a diffusion method assuming relatively strong selection. It is shown...

The successful development and implementation of rotavirus vaccines will have a significant impact on rotavirus-induced gastroenteritis in children worldwide. However, this introduction will increase the immune pressure against wild-type rotavirus strains circulating in the community, altering the forces and balances that drive rotavirus evolution. There is concern that antigenically distinct n...

Younger age groups account for proportionally more mortality in influenza pandemics than in seasonal influenza epidemics. Mechanisms that might explain this include young people suffering from an over-reactive immune system ("cytokine storm"), older people benefiting from cross-immunity from a wider variety of previous influenza infections ("antigenic history"), and lifetime immune responses in...

In 2004, canine influenza virus subtype H3N8 emerged in greyhounds in the United States. Subsequent serologic evidence indicated virus circulation in dog breeds other than greyhounds, but the virus had not been isolated from affected animals. In 2005, we conducted virologic investigation of 7 nongreyhound dogs that died from respiratory disease in Florida and isolated influenza subtype H3N8 vir...

Recently, concern has been voiced about the potential effect that antigenic divergence of circulating strains of Bordetella pertussis might have on the efficacy of pertussis vaccines. In order to model antigenic drift of pertussis toxin, a critical component of many pertussis vaccines, and to examine the effects of such drift on antibody neutralization, we engineered a strain of B. pertussis to...

We describe a multiple strain Susceptible Infected Recovered deterministic model for the spread of an influenza subtype within a population. The model incorporates appearance of new strains due to antigenic drift, and partial immunity to reinfection with related circulating strains. It also includes optional seasonal forcing of the transmission rate of the virus, which allows for comparison bet...

The complete genomic sequence of one human isolate of West Nile virus (WNV) and the partial genomic sequences of 14 other strains from India isolated in the period 1955-1982 from different hosts and geographical areas were determined. Phylogenetic analyses based on complete and partial genomic sequences (921 nt of the C-prM-E region) revealed that WNV could be classified into five distinct grou...