It has been known since the Middle Ages that rodents carry disease and rodents often live in proximity to humans (especially if you leave your chickens' feed exposed). So you do not have to be a rocket scientist to hypothesize that declines in large wildlife that affect the size of rodent populations plays a role in suppressing the spread of disease to humans. Another kind of scientist studying wildlife on the East African savannas found exactly that expected correlation. When numbers of large animals decreased an increase in the risk of human disease regularly followed. An ecologist from the University of California, Santa Barbara and her team studied the effect of large wildlife on rodent populations and
Bartonellosis a group of bacterial pathogens. Rodent populations explode in the absence of large animals. When elephants, giraffe and zebra are kept of out large areas of land in Kenya, rodent populations double which of course doubles the number of disease carrying fleas. The relationship even has a name, "rodentation" and can occur anywhere not just on the African savannas. And now that the entire world is connected by a few days of air travel at the most the outbreak of coronavirus diseases like SARS and MERS in remote rural locations poses a threat to urban human populations in cities like New York and Los Angeles. The research is published in the
Proceedings of the National Academy of Sciences, online edition.
