Report: Superbug transmitted from zoo elephant to human caretakers
An outbreak of MRSA skin infections at the San Diego Zoo last year began when a zookeeper infected an elephant calf that was being hand-raised because its mother couldn’t care for it, according to an investigation. The calf, in turn, infected as many as 20 of its human caretakers.
Those most likely to be infected were zookeepers with such close contact as bottle-feeding the calf, playing with it, laying alongside it and using their mouths to blow into its trunk -- a technique to encourage the calf to take milk from a bottle. The Centers for Disease Control and Prevention, which published the results of the investigation today in its Weekly Morbidity and Mortality Report, described the case as the first known instance of methicillin resistant Staphylococcus aureus, or MRSA, in a zoo elephant and the first known transmission of the superbug from a zoo animal to a human.
But the report sheds light on a growing concern among veterinarians that the skin infections that have become a leading cause of human admissions to hospital emergency rooms are being passed back and forth among people and animals.
MRSA strains isolated from household pets typically are human strains acquired from human contacts, the report said. The strain isolated from the elephant calf was USA300, the strain that has become infamous for causing infections in wrestlers, football players and others who engage in close-contact sports. The bacterium is spread through skin-to-skin contact or sharing personal items, such as towels or sports equipment.
None of the other elephants, including the calf’s mother, were found to be either infected with that strain or to be carriers. The 2-month-old calf, a female African elephant that was never given a name, was euthanized Feb. 4, 2008, but not because of MRSA, zoo officials said.
Its infection had healed after treatment with topical, oral and intravenous antibiotics, but it nevertheless failed to thrive. The calf was born in late November 2007 and was separated from its mother a month later to be hand-raised. Fifty-five zookeepers cared for the young elephant, and 20, or 36%, of them developed confirmed or suspected MRSA infections. Most were mild pustules and lesions on the hands, forearms and wrists.
-- Mary Engel