Читать книгу Honey Bee Medicine for the Veterinary Practitioner - Группа авторов - Страница 30

The method by which a disease is transmitted from colony to colony is a fundamental determinant of pathogen virulence. Vertical transmission (the spread of disease from parent to offspring) favors the evolution of avirulence whereas horizontal transmission (the spread of disease among unrelated individuals) favors the evolution of virulence (Lipstich et al. 1996). This is because pathogens and parasites that spread vertically need their host to stay healthy to produce offspring, whereas those that spread horizontally do not have this need. Although numerous other host factors (i.e. host longevity, density, population structure, and novel hosts) and pathogen factors (i.e. vector availability and pathogen replication potential) also influence virulence, we will focus on how the mode of honey bee pathogen and parasite transmission within and among colonies impacts the evolution of the virulence of these agents of disease.