Table 1 Morphological differences of O. petrowi in intermediate and definitive host
Stage | DPI | Length | Morphological differences |
|---|---|---|---|
Intermediate host | |||
First-stage (L1) | 12 | 14–235 µm | Indistinct internal organs No clear nerve-rings Esophagus and intestine were not clear No excretory pore |
Second-stage (L2) | 29 | 625–770 µm | Well-developed esophagus and intestine |
Third-stage (L3) | 42 | 7.0–8.5 mm | Anterior of the esophagus surrounded by large number of cells Six lobes clearly seen on anterior oral opening |
Definitive host | |||
Fourth-stage (L4) | 7 | 10.6–11.7 mm | Absence of copulatory spicule in male and incomplete ovary in female Displacement in the intestine for development of reproductive organs in both male and female |
Sub-adults | 28 | 10.5–13.0 mm | Copulatory spicules in the male Female now carrying unembryonated eggs |
Adults Male Female | 49 | 13.5–14.3 mm 16.0–17.0 mm | Matured cuticular buccal capsule in both male and female Development of full reproductive organs: males exhibiting everted spicules and females carrying embryonated eggs within the oviduct Considerable difference between male and female length |