Chrysomya spp

From Cow

Chrysomya spp (f. Calliphoridae) are a parasitic Old World screw-worm fly which causes myiasis and secondary disease in cattle worldwide[1].

Species of Chrysomya which are pathogenic to cattle include:

  • C. bezziana (Africa, Indian, Asia)[2]
  • C. marginalis
  • C. putoria[3]
  • C. megacephala[4]

Chrysomya spp primarily cause myiasis, with females laying egss in open wounds. The larvae are obligate parasites.

All wounds on domestic animals should be properly dressed, and all elective surgical procedures avoided during the fly season.

Chrysomya spp larvae cause intense pruritus.

Topical insecticides such as ivermectin and pyrethrins (eg, cypermethrin or cyfluthrin) help control these parasites[5]. Non-sticky traps and fly attractant are also used to control adult fly populations around cattle herds.


  1. Merck Vet Manual
  2. Urech R et al (2012) Field assessment of synthetic attractants and traps for the Old World screw-worm fly, Chrysomya bezziana. Vet Parasitol 187(3-4):486-490
  3. Corrêa EC et al (2010) Chrysomya (Diptera: Calliphoridae) relative abundance and species seasonality in the Pantanal, State of Mato Grosso do Sul, Brazil. Rev Bras Parasitol Vet 19(2):85-88
  4. Marchiori CH et al (2007) Parasitoids of muscoids diptera collected at Alvorada slaughterhouse in Itumbiara, south of Goiás, Brazil. Rev Bras Parasitol Vet 16(4):235-237
  5. Romaniuk K (1999) The influence of diptera on the domestic animals. Wiad Parazytol 45(3):323-326