While the number of viruses available to make such a species jump
is unknown, studies such as that by Anthony and coworkers (1) provide rough estimates on the order of 320,000 currently circulating viral species in worldwide mammalian populations alone.
Emerging pathogens: the epidemiology and evolution of species jump
. Trends Ecol Evol.
Prof Sharp added: "We want to understand which genetic differences in SIVcpz and HIV-1 evolved after the species jump
Since 1997, the first two prerequisites--a novel viral strain in animals and a "species jump
" from animals to humans--have been met on four occasions.
Because chimpanzees were killed for food in parts of sub-Saharan Africa, the species jump
probably occurred when a hunter was exposed to the blood of an infected chimpanzee during its butchering.
An ocean away, as forays into sub-Saharan Africa tempted settlers to add bush meat to their sparse diets, HIV made the species jump
, Waiters suggests, propelling a worldwide AIDS pandemic.
brunneus were seen in grass at the base of the first-floor pallet, while a nymph of the same species jumped
from an adjacent bramble leaf onto the second floor.
Defense spending on threatened and endangered species jumped
nearly 45 percent over the past decade from about $50 million a year in 2003 to about $73 million in 2012.
The rate of birth of new species jumped
as this new shape evolved, and this group of bats quickly increased the proportion of fruit in their diet.
Woodland bird species jumped
42% in the North West, and by almost a third (30%) in Yorkshire and the Humber regions between 1994 and 2007..
Because only four lizard species jumped
during feeding, and no more than one or two lizards within each species jumped
during escape, we decided that these sample sizes were insufficient to either have sufficient power for correlations (for feeding) or accurately estimate mean values (for escape).