Redescription and genetic characterization of selected Contracaecum spp. (Nematoda: Anisakidae) from various hosts in Australia

Abstract

In the present study, five species of Contracaecum Railliet & Henry 1912 (Nematoda: Ascaridida), including Contracaecum bancrofti, Contracaecum microcephalum, Contracaecum variegatum, Contracaecum eudyptulae, and Contracaecum ogmorhini, were redescribed using light and scanning electron microscopy. In addition, in order to elucidate their taxonomic status, first and second internal transcribed spacers (ITS-1 and ITS-2, respectively) of nuclear ribosomal DNA of each morphospecies were characterized. Analyses of sequence and morphological data sets suggested that C. bancrofti, infecting the Australian pelican Pelecanus conspicillatus, is a valid species and is distinct from C. micropapillatum reported from pelicans in the northern hemisphere. C. microcephalum from cormorants Phalacrocorax melanoleucos and C. variegatum from the darter Anhinga melanogaster and from P. conspicillatus as well as C. eudyptulae from the little penguin Eudyptula minor were also considered as distinct species, which can be differentiated from one another morphologically based on the lengths of spicules and genetically based on the sequences of ITS-1 and ITS-2. Comparison of sequence data of ITS-1 and ITS-2 for the members of C. ogmorhini sensu lato from pinnipeds with those of previous studies suggested that only ITS-2 can be used for differentiation between C. ogmorhini sensu stricto and Contracaecum margolisi, occurring in the southern and northern hemispheres, respectively. Analyses of the ITS-1 and ITS-2 sequence data of Contracaecum spp. in the present study supported the distinction among species of Contracaecum based on morphological data and were useful in confirming the taxonomic status of individual species in Australia.

Occurrence and abundance of anisakid nematode larvae in five species of fish from southern Australian waters

“…Genomic DNA was also isolated from the musculature of fishes using the same method. PCR was used to amplify the internal transcribed spacer (ITS-2) region using primer pairs and conditions described previously (Shamsi et al 2008(Shamsi et al , 2009b. Fish DNA and no-template (negative) controls were subjected to PCR; no amplicons were produced from these samples.…”

Anisakid Nematode (Ascaridoidea) Life Cycles and Distribution: Increasing Zoonotic Potential in the Time of Climate Change?

“…of the genera Larus, Pelecanus, Phalacrocorax) have been identified as final hosts in the Contracaecum life cycle (e.g. Torres et al 1983;Farjallah et al 2008;Mattiucci and Nascetti 2008;Shamshi et al 2009a; Fig. 11.4).…”

The occurrence of Contracaecum sp. larvae (Nematoda: Anisakidae) in four teleostean species from Lake Nasser, Egypt: morphological and molecular studies

“…ITS-1 of SF larvae collected from H. forskahlii showed the highest similarity (97%) to three ITS-1 sequences (Accession numbers FM210433-FM210434-FM210435) from C. multipapillatum L3 Fig. 4 Scanning electron micrographs showing the pattern of cuticular striations in: a larva collected from Oreochromis niloticus and Tilapia galilae; b short form larva collected from Lates niloticus; c long form larva collected from Lates niloticus; d short form larva collected from Hydrocynus forskahlii; e long form larva collected from Hydrocynus forskahlii which were collected from intestine and body cavity of barboid fishes in Parishan Lake, Iran (Shamsi & Aghazadeh-Meshgi, 2011). Further, ITS-2 of the same larvae (SF L3 from H. forskahlii) showed the highest similarity (98%) to the previously abovementioned three ITS-2 sequences of Contracaecum L3 (Accession numbers FM210437-FM210438-FM210439).…”