July 2017

Stray dog

​​​Animal Control in Dade County, Miami, Florida was called when a stray dog was seen roaming through a suburban neighborhood. The public was concerned that the dog may be rabid due to its emaciated condition and apparent neurologic signs. Animal Control successfully trapped the dog and took it to a local veterinary clinic. The following organisms were found inside several open wounds on the dog.

What is your diagnosis?

​Many thanks to Katie Huffman, 4th year veterinary student from Virginia Tech for providing case content.

Answer

​These are Cochliomyia hominovax larvae, also known as the New World screw-worm, or simply screw-worm. These larvae can be identified by the set of distinct, dark-colored tracheal trunks located at the posterior end. Some of the cuticle on several of the larvae pictured here has been trimmed away to better visualize these structures. The maggots eat the living tissue of warm-blooded animals, an condition called myiasis. State and federal authorities should be contacted if an animal in North America is infested with screw-worm larvae. This parasite was eradicated in the United States in the 1980s with the sterile male release program. However, in August of 2016, C. hominovorax was identified in the Key islands off of the Florida coast, and has since made its way into Dade County, Miami, Florida.