Abstract
Some microbes are not very picky about where they live. ‘Diseases across species’ explains that the multi-way spread of microbes and parasites across species is concerning for several reasons: it means they can have a greater impact on more animals—of any species—who can get infected; it enlarges our ‘herd’ of animals through which microbes may spread; and as microbes spread across species, they might change in ways that make them more dangerous for other species. The different ways in which the cross-species spread of microbes can be reduced are discussed along with concern about superbugs—the microbes and parasites that evolve quickly, becoming resistant to antibiotic drugs.