Oestrus ovis eksternal oftalmomiyazisin en yaygin etkeni olmakla beraber Calliphora, Sarcophaga, Gastrophilus, Hyopoderma, Callitroga, Cuterebra, Dermatobia, Wohllfahrtia gibi sinek turleri de oftalmomiyazise neden olabilir.2,3 Oestrus ovis yasam siklusunun larva donemini koyun ve kecilerin burun bosluklarinda geciren zorunlu bir parazittir.
Among ectoparasites, ticks were recorded from majority (n=18/450) of the equines followed by mites (n=07/450) and Gastrophilus (G.) nasalis (n=03/450).