title: Incidence and histopathology of encysted progenetic metacercaria of Clinostomum complanatum (Digenea: Clinostomidae) in Channa punctatus and its development in experimental host.
abstract: 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. complanatum cysts. 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. complanatum in C. punctatus revealed the prevalence, intensity and abundance of 24.7%, 2.27 and 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. complanatum metacercaria either in the excysted or encysted form, indicating loose host specificity and zoonotic potential.
authors.affiliation: Section of Parasitology, Department of Zoology, Aligarh Muslim University, Aligarh, U.P., Pin: 202 002, India.
authors.forename: P A Ahammed
authors.initials: PA
authors.lastname: Shareef
authors.forename: Sma
authors.initials: S
authors.lastname: Abidi
mesh_terms: D000818:Animals; D002645:Chickens; D043344:Chordata / Q000469:parasitology*; D004195:Disease Models, Animal; D005393:Fish Diseases / Q000453:epidemiology* / Q000469:parasitology / Q000473:pathology; D006651:Histocytochemistry; D015994:Incidence; D007194:India; D058488:Metacercariae / Q000254:growth & development* / Q000302:isolation & purification*; D008853:Microscopy; D010274:Parasitology; D014200:Trematoda / Q000254:growth & development* / Q000302:isolation & purification*; D014201:Trematode Infections / Q000453:epidemiology / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*
keywords: Channa punctatus; Clinostomum complanatum; Encysted progenetic metacercaria; Experimental infection; Histopathology; Host-parasite interaction; Incidence; Metacercarial transformation; Ovigerous adult worm