Alert Floridians tighten the screw on screwworms

The USDA reported in May that investigation of the Florida equine screwworm case, which occurred in March, has concluded. From mid-March until mid-April, sentinel calves were placed in the area in Florida where the screwworm had turned up. Twice-daily inspections revealed no evidence of screwworm infestation.

A vigorous screwworm alert campaign was staged in Florida after the incident occurred (see JAVMA April 15, 2000, page 1200), resulting in vigilant efforts on the part of many in the health field, with some notable examples in veterinary practice.

In March, a Clay County, Florida, practitioner observed and collected fly larvae from wounds on a male cat. She turned over the larvae to the National Veterinary Services Laboratories, which identified it as the green bottle fly. Early in April, a practitioner discovered fly-strike on a domestic cat in the Lakeland, Fla area. The larvae were identified as the third instar stage of the black blow fly. In Okeechobee County, Florida, a calf with an umbilical lesion was examined and not found to have larvae, and the remainder of the herd was clinically normal.

No screwworms were identified in the incidents, but these practitioners heard and heeded the public warnings, emphasizing the effectiveness of the campaign.