Ecoepidemia con difesa di gruppo: le prede infette restano nel branco

In general ecoepidemic models contain a basic interacting population system on top of which a contagious disease is present. The models we consider here are a prey-predator systems in which the disease develops in prey: the latter gather together and live in a herd. They can occupy any position in the bunch, including the ones near the boundary. In particular we study three types of models which vary depending on the effect that the disease has on the two species: in all cases it is assumed that this makes the affected individuals unable to reproduce and always leads to death. In the first model it is assumed that the disease is particularly virulent for prey, but advantageous for predators. In the second, infection is assumed less invasive for the prey, and predators do not gain any special benefit by eating infected individuals. The third and last model differ in the fact that the disease does not weaken in a particular way their prey, however, it causes the death of the predators.