Mathematical Epidemiology and Disease Spread Modeling

Spatial dynamics of bar-headed geese migration in the context of H5N1

Virulent outbreaks of highly pathogenic avian influenza (HPAI) since 2005 have raised the question about the roles of migratory and wild birds in the transmission of HPAI. Despite increased monitoring, the role of wild waterfowl as the primary source of the highly pathogenic H5N1 has not been clearly established. The impact of outbreaks of HPAI among species of wild birds which are already endangered can nevertheless have devastating consequences for the local and non-local ecology where migratory species are established. Understanding the entangled dynamics of migration and the disease... more

From regional pulse vaccination to global disease eradication: insights from a mathematical model of poliomyelitis

Mass-vaccination campaigns are an important strategy in the global fight against poliomyelitis and measles. The large-scale logistics required for these mass immunisation campaigns magnifies the need for research into the effectiveness and optimal deployment of pulse vaccination. In order to better understand this control strategy, we propose a mathematical model accounting for the disease dynamics in connected regions, incorporating seasonality, environmental reservoirs and independent periodic pulse vaccination schedules in each region. The effective reproduction number, Re,... more

Role of the interaction of migratory bird species with nonmigratory poultry in sustaining H5N1 avian influenza

We investigate the role of migratory birds in the spread of H5N1 avian influenza, focusing on the interaction of a migratory bird species with nonmigratory poultry. The model is of patch type and is derived with the aid of reaction-advection equations for the migratory birds in the air along the flyways. Poultry may reside at some or all of the four patches of the model, which consist of the breeding patch for the migratory birds, their winter feeding patch, and two stopover patches where birds rest and refuel on their migration. Outward and return migratory routes can be different. The... more

Highly pathogenic avian influenza outbreak mitigated by seasonal low pathogenic strains: Insights from dynamic modeling

The spread of highly pathogenic avian influenza (HPAI) H5N1 remains a threat for both wild and domestic bird populations, while low pathogenic avian influenza (LPAI) strains have been reported to induce partial immunity to HPAI in poultry and some wild birds inoculated with both HPAI and LPAI strains. Here, based on the reported data and experiments, we develop a two-strain avian influenza model to examine the extent to which this partial immunity observed at the individual level can affect the outcome of the outbreaks among migratory birds in the wild at the population level during... more

Understanding the transmission of H5N1

H5N1 influenza virus is now endemic in many regions of the world. Outbreaks continue to occur with dev- astating impacts to the local economies and threatening human health. The transmission of the virus involves a complex interplay between the spatio-temporal dynamics of the potential avian hosts, the ecology of the virus and poultry farming and trade. Despite increased monitoring of wild bird populations and poultry trade, control measures remain insufficient to mitigate the spread of the virus. Here, focus is given on the influence of seasonality of migration and breeding in the... more