1Wild Animal Park, San Diego Zoo, Escondido, CA, USA; 2Wildlife Disease Laboratories, Institute for Conservation Research, San Diego Zoo, San Diego, CA, USA; 3Centers for Disease Control and Prevention, San Diego County Community Epidemiology, San Diego, CA, USA; 4Animal Disease Diagnostic Laboratory, County of San Diego, San Diego, CA, USA
Abstract
A 3-week-old African elephant (Loxodonta africana) calf, whose mother had a retained placenta and decreased milk production, was hand-reared but failed to thrive. At 7-weeks-old, the calf developed a purulent discharge from a large, abraded skin wound on the left forelimb and smaller wound on the rear limb followed by cellulitis at a venous cutdown site. Cultures from the elbow and rear limb grew methicillin-resistant Staphylococcus aureus (MRSA). Approximately 1 week later, several of the calf’s caretakers reported cutaneous pustules, some of which were laboratory confirmed as MRSA. The calf was treated with antibiotics, and the wounds healed. Nevertheless, the calf failed to thrive and was euthanatized. Postmortem examination of the calf revealed evidence of bacterial septicemia (Enterococcus spp.), though not consistent with MRSA. The calf’s skin lesions were chronic with superficial, opportunistic bacterial and fungal colonization.
A retrospective cohort study of all caretakers was conducted. Twenty MRSA wound infections (five laboratory-confirmed and 15 suspected cases) were identified among the calf’s caretakers (attack rate [20/55]=36%). Most skin infections were mild, occurred on uncovered skin surfaces, and did not require hospitalization. Pulse-field gel electrophoresis results from the elephant calf, three caretakers’ wounds, and nasal isolates from two caretakers were USA300, the MRSA type most commonly identified in community-associated MRSA infections in the United States. No MRSA colonization or skin infections were found in other African elephants with which the calf shared living space. Among caretakers, activities involving direct contact with the calf (e.g., grooming, bathing, and playing with the calf) were associated with infection.1
The investigation determined that the elephant calf likely acquired its MRSA infection from a colonized human caretaker and then passed the infection to other human caretakers through close direct contact. This case demonstrates the importance of maintaining rigorous infection control procedures with sick animals, especially when caring for animals in critical care situations and/or with open wounds. The recent Compendium of Veterinary Standard Precautions provides a good starting point for developing practice standards for infection control in zoos.2
Literature Cited
1. Methicillin-resistant Staphylococcus aureus skin infections from an elephant calf—San Diego, California, 2008. MMWR. 58:194–198.
2. National Association of State Public Health Veterinarians. 2008. Compendium of veterinary standard precautions for zoonotic disease prevention in veterinary personnel. J Am Vet Med Assoc. 233:415–430.