Development and hatching mechanism of Fasciola eggs, light and scanning electron microscopic studies

Abstract

Both light microscopy and scanning electron microscopy were used in the description. There were variable measurements of eggs from the same fluke and there was no relationship between the size of the fluke and size of eggs. Light microscopy revealed that the operculum has different shapes in Fasciola gigantica and F. hepatica. Under normal laboratory conditions of temperature (26 ± 1 °C), miracidia of F. gigantica developed within 12-16 days period, but those of F. hepatica developed within a period of 13-15 days. The miracidia of F. gigantica measured 110 × 70 μm and that of F. hepatica measured 136 × 74 μm. The life span of the miracidium in F. gigantica ranged between 9 and 12 h, while in F. hepatica the life span did not exceed 10 h. Miracidial epidermal plates in miracidium of F. gigantica were found to be 20 plates arranged in four tiers of six, four, six and four. Hatching process was recorded using scanning electron microscope, and it indicated partially opened operculum.

Effect of Host Species on Hatchability of Fasciola hepatica and Fasciola gigantica Eggs from Sheep and Cattle

“…The genetic nature of native parasites may influence morphometric characteristics of Fasciola eggs reported in these studies. The hatching period for F. hepatica was 13-15 days and shorter than 12-16 days of F. gigantica [16]. Therefore, on day 15 of incubation, most F. hepatica eggs developed earlier than F. gigantica, as seen in the present study.…”

“…In the current study, the hatching rates of F. gigantica and F. hepatica originated from cattle were higher than those from sheep, while there was no change in the percentage of developed eggs in the two hosts. Miracidia maturation occurs within 12-16 days in eggs of both F. hepatica and F. gigantica regardless of the host species [16]. Several reports showed that the chemical composition of various plant extracts [19] could penetrate the eggshell and inhibit the egg hatching depending on the solubility in lipids [20].…”

“…Studying various parasite life cycle stages can open new ground for control and prevention programs to reduce the final host's infection risk [15]. Some reports have indicated the impact of environmental factors on the hatching Fasciola spp eggs [12,16]; however, the data on the host role in larva development and egg hatching is limited. Ashrafi et al (2006) showed that the age of the host, helminth, and method of preparing the specimens affect the adult Fasciola eggs morphological characteristics [17].…”

A mathematical model for the seasonal transmission of schistosomiasis in the lake and marshland regions of China

“…By escaping from the snail, the infective cercariae penetrate the skin of the human host. For more details on the life cycle of schistosome, we refer to [5,7,12,16,17,23,28,30,6]. To focus on the dynamics of S.Japonicum propagating between human and the intermediate host snails, we consider a simplified diagram for the life cycle given in Figure 2.…”

What is hidden under an eggshell? Ultrastructural evidence on morphology of “passive” Prosorhynchus squamatus miracidium (Digenea: Bucephalidae)

“…Miracidia with active strategy of infection are generally larger: e.g. in Fasciola and Schistosoma they are between 100-200 µm in length (Southgate, Knowles, 1977;Hussein et al, 2010), and in Cyclocoelidae may be up to 340 µm (Ginetsinskaya, 1954). However, in several other groups "active" miracidia are as small as 50-70 µm (Allocreadiidae (Peters, LaBonte, 1965;Cannon, 1971), Zoogonidae (our unpublished data), Gorgoderidae (Goodchild, 1948)).…”