Efficacy of UV-C Ray Sterilization of Calliphora vicina (Diptera: Calliphoridae) Eggs for Use in Maggot Debridement Therapy

Maggot debridement therapy (MDT) is a simple wound debridement technique. It is a natural treatment licensed by the Food and Drug Administration (FDA) and is increasingly used in the United States and in Europe.This treatment is safe when the larvae originate from laboratory stocks of eggs that have been sterilized. In this study, a simple, inexpensive microbe decontamination technique is described. It yields eggs that are free of chemical residues and are easy to handle, meeting the growing demand for medicinal larvae in hospitals or medical centers. Three treatments (T1,T2,T3) involving 3, 6, and 12 min of exposure to ultraviolet (UV-C) rays, respectively, were compared. Egg sterility was evaluated by culture in thioglycollate broth, incubated at 32°C ± 2.5°C under aerobic conditions for up to 14 d. The UV-C radiation sterilization process obtained satisfactory results after 12 min exposure (treatment 3). Larval viability was 57%, pupal viability was 54%, and 54% of the adults emerged.The sex ratio was 50%, within the expected values. There were no morphological abnormalities associated to the UV-C treatment in the flies. In conclusion sterilization by UV-C rays is indicated to obtain sterile larvae destined for MDT.