ABSTRACT
Larvae (maggots) of Cochliomyia hominivorax, the New World Screwworm fly, are voracious consumers of living flesh that have a negative economic impact by decreasing productivity, predisposing to other pathogens, and, in severe cases, causing death of domestic livestock. Screwworm caused extensive financial losses to the livestock industry in North America prior to its eradication. Sterile insect technique (SIT) was used to eradicate screwworm throughout North and Central America and continues to be the main tool to control it in eastern Panama. The goal of this study was to evaluate the temporal and spatial trends of screwworm myiasis cases reported in the Province of Darien and Comarca Embera (border with Colombia), Panama, from 2001 to 2011. We hypothesized that screwworm cases would vary seasonally and be spatially clustered near Colombia as a result of effective eradication strategies in Panama and the presence of an autochthonous population of flies in western Colombia. Temporal and spatial data were retrieved from COPEG-USDA records (Panama) and analysed by anova, Ripley's K function, discrete Poisson spatial statistic scan and Getis-Ord Gi*. No significant temporal trend was found, but cases were spatially distributed in four clusters. One cluster of cases occurred from 2001 to 2003 and was considered a focal temporal and spatial cluster. One cluster occurred in 2001 and 2007 indicating more rare outbreaks in an area with fewer cattle. The two remaining clusters contained cases from 2004 to 2011 and 2001 to 2011 suggesting regular breaks in the control barrier due to occasional failures of the SIT programme, difficulties implementing border quarantine strategies, livestock smuggling or the movement of infested wildlife.
