Incidence and histopathology of encysted progenetic metacercaria of Clinostomum complanatum(Digenea:Clinostomidae) in Channa punctatus and its development in experimental host

Objective:To study the incidence of encysted progenetic metacercariae of Clinostomum complanatum(C. complanatum) in Channa punctatus(C. punctatus), associated histopathology and the experimental infection to laboratory chicken to obtain ovigerous adult worms.Methods:Live C. punctatus were brought from local fish market of Aligarh, India, dissected and examined on a monthly basis for the presence of C. complanatumcysts. For histochemistry, infected tissue sections with attached cysts were processed for haematoxylene and eosin staining. Cysts were aseptically fed to 4 day old leghorn chicken to obtain adult worms. Mechanically excysted metacercaria and the ovigerous adult worms were stained in carmine to prepare permanent slides.Results:One year survey for the infection of encysted progenetic metacercaria of C.complanatuminC. punctatusrevealed the prevalence, intensity and abundance of 24.7%, 2.27and 0.608, respectively. Histopathology showed heavy infiltration of immune cells at the site of cyst attachment and some tissue damage was also evident. Following feeding to experimental chicken, about 41.07% of the encysted metacercariae were able to excyst and migrate back to bucco-pharyngeal region where they tenaciously attached and fed on blood, and transformed into ovigerous adult worms from 62 hours onwards of post infection.Conclusions:The parasite is potentially pathogenic to the host, and the availability of a suitable intermediate host can be a contributing factor for the occurrence of C. complanatummetacercaria either in the excysted or encysted form, indicating loose host specificity and zoonotic potential.

Meteorite impact craters as hotspots for mineral resources and energy fuels:A global review

The ever-increasing recovery rate of natural resources from terrestrial impact craters over the last fewdecades across the globe offers new avenues for further exploration of mineral and hydrocarbon resources in such settings.As of today,60 of the 208 terrestrial craters have been identified to host diverseresources such as hydrocarbons,metals and construction materials.The potential of craters as plausibleresource contributors to the energy sector is therefore,worthy of consideration,as 42(70%)of the 60craters host energy resources such as oil,gas,coal,uranium,mercury,critical and major minerals as wellas hydropower resources.Among others,19 craters are of well-developed hydrocarbon reserves.Mineraldeposits associated with craters are also classified similar to other mineral resources such as progenetic,syngenetic and epigenetic sources.Of these,the progenetic and syngenetic mineralization are confinedto the early and late excavation stage of impact crater evolution,respectively,whereas epigenetic deposits are formed during and after the modification stage of crater formation.Thus,progenetic andsyngenetic mineral deposits(like Fe,Ni,Pb,Zn and Cu)associated with craters are formed as a directresult of the impact event,whereas epigenetic deposits(e.g.hydrocarbon)are hosted by the impactstructure and result from post-impact processes.In the progenetic and syngenetic deposits,the shockwave induced fracturing and melting aid the formation of deposits,whereas in the epigenetic deposits,the highly fractured lithostratigraphic units of higher porosity and permeability,like the centralelevated area(CEA)or the rim,act as traps.In this review,we provide a holistic view of the mineral andenergy resources associated with impact craters,and use some of the remote sensing techniques toidentify the mineral deposits as supplemented by a schematic model of the types of deposits formedduring cratering process.