The life cycle ofContracaecum osculatum (Rudolphi, 1802) sensu stricto (Nematoda, Ascaridoidea, Anisakidae) in view of experimental infections

Abstract

Hatched, ensheathed third-stage larvae of Contracaecum osculatum, 300-320 microns long, were shown to be infective to copepods, to nauplius larvae of Balanus and to small specimens of fishes (sticklebacks, O-group eelpout). Other fishes such as gobies and small flatfishes became infected by ingesting infected crustaceans. Cod were infected by being given infected small fishes. In the crustacean paratenic hosts, little growth of the larvae occurred, if any. In the liver sinusoids of sticklebacks and gobies the length of most of the unencapsulated third-stage larvae had not even doubled within 6 months of infection. The fate of larvae (max. 2 mm long) given to cod via infected intermediate fish hosts was apparently decided by the size of the larvae only. Small larvae became encapsulated and eventually died in the liver and wall of the gastrointestinal tract. Larger larvae migrated to the liver parenchyma, where some grew to a length of as much as 10 mm. The growth of the larvae in sticklebacks was shown not to be affected by an increase in temperature (infected fish being transferred from 8 degrees to 14 degrees and 20 degrees C), by the intensity of infection and, partly, by the age of infection (e.g. some 2-week-old and 6-month-old larvae were of identical size). In the liver and mesentery of plaice the third-stage larvae developed via copepod paratenic hosts to infectivity (i.e. to more than 4 mm in length), showing that the life cycle may be completed with an optional paratenic invertebrate host and only one intermediate fish host.(ABSTRACT TRUNCATED AT 250 WORDS)

Nematodes in Hoplerytrinus unitaeniatus, Hoplias malabaricus and Pygocentrus nattereri (pisces characiformes) in Marajó Island, Brazil

“…Fish can act as the second intermediate hosts by feeding on parasitized crustaceans or on paratenic hosts, in the case of predatory fish. In both cases, fish may be a source of infection for piscivorous birds and marine mammals FAGERHOLM, 1995;ANDERSON, 2000). In parasitism involving Eustrongylides sp., the definitive hosts are piscivorous birds; while in infections with Contracaecum sp., fish participate as the second intermediate hosts and contamination occurs after ingestion of parasitized oligochaetes (COLE, 1999;COYNER et al, 2001).…”

Phylogeny of the Ascaridoidea (Nematoda: Ascaridida) Based on Three Genes and Morphology: Hypotheses of Structural and Sequence Evolution

“…For example, members of this superfamily have been used for studies of respiratory biochemistry (Saz and Weil, 1960;Komuniecki et al, 1993), molecular genetics (Neuhaus et al, 1987;Kageyama, 1998), immunology (Jones et al, 1994), reproductive biology (Von Beneden, 1883;Foor, 1970), comparative morphology (Fagerholm, 1989(Fagerholm, , 1991Hugot et al, 1991), development (Boveri, 1899;Pilitt et al, 1981), life cycles (Huizinga, 1967;Klöser et al, 1992;Køie and Fagerholm, 1995), population genetics Nascetti et al, 1993;Nadler, 1996), and pathology (Beaver, 1956;Overstreet and Meyer, 1981;Kazacos, 1986). In contrast, much less is known about the evolutionary history of taxa in this superfamily, although certain organisms, e.g., Ascaris, Anisakis, have been studied in detail at the microevolutionary level (Paggi et al, 1991;Anderson et al, , 1995Anderson and Jaenike, 1997).…”

Oceanological and Hydrobiological Studies

“…It is thus plausible that C. osculatum baicalensis can be transmitted also by Baikal copepods (Rusinek 2007), as it is in the case of marine copepods and C. osculatum s.l. (Koie & Fagerholm 1995). Should it be the case, it would considerably increase the range of the nematode targets, as the above-mentioned copepods are the main food source of young C. grewingkii and C. inermis and thus the fish can be infected very early by the larval C. osculatum baicalensis.…”