Description: In April 1990, 488 marine fish, belonging to 30 species from central Philippine waters, were investigated macroscopically for the occurrence of parasites in their flesh and for anisakid nematodes in their body cavity. Twenty-four fish were found to be infected by 1 of 4 different types of parasites. Unidentified Microspora were found in 4 host species from different families. Plerocercoids of the trypanorhynchid cestode Otobothrium penetrans occurred in the flesh of hemirhamphids and belonids only. Adult nematodes of the genus Philometra were found in the garfish Tylosurus crocodilus. The only parasite found which might be transferable to warm-blooded animals was the L-III stage of Anisakis sp. from the body cavity and the muscle of Muraenesox cinereus. The risk of human infections by parasites through consumption of raw marine fish in the central Philippines therefore is considered to be low.

Description: Eleven fish species from the Weddell Sea (Antarctic) were examined for infestation with anisakid nematodes. Two species of the genus Contracaecum and the sealworm Pseudoterranova decipiens were isolated from the liver and the body cavity of fish affected. Only two specimens of P. decipiens (1.4%) partly invaded the belly flaps. The following fish species were infested by P. decipiens at the given prevalences: Cygnodraco mawsoni (74.4%), Trematomus scotti (23.2%), Pagetopsis maculatus (10.0%), Cryodraco antarcticus (7.1%), Trematomus lepidorhinus (3.0%), and Dolloidraco longedorsalis (2.7%). All of these, except Trematomus scotti, are new host records. Chaenodraco wilsoni, Chionodraco myersi, Gerlachea australis, Racovitzia glacialis and T. eulepidotus were not infested. The reasons for low prevalence and intensity of infestation are seen in the difficulties of P. decipiens in completing its benthic life cycle in the Weddell Sea environment, in the absence of shallow coastal waters due to the floating shelf-ice. Cygnodraco mawsoni is a crucial intermediate host, without which completion of the parasite life cycle might not be possible. In order to clarify the taxonomical position of Antarctic Pseudoterranova, morphological comparisons with specimens of P. decipiens from the German and Norwegian coast were made using scanning electron microscopy. Results revealed no differences; hence, all specimens studied belong to the same species P. decipiens.

Description: A wide spectrum of fish hosts in the Gulf of Guinea was examined for infestation with trypanorhynchid cestodes. A total of 1341 specimens belonging to 45 species were examined. The following 9 trypanorhynchid species were identified: Callitetrarhynchus gracilis, Grillotia perelica, Nybelinia sp., Otobothrium cysticum, O. dipsacum, Otobothrium sp., Poecilancistrum caryophyllum, Ptero-bothrium sp. and one unidentified species. The pattern of occurrence of Callitetrarhynchus gracilis has been used to draw conclusions on a possible 4-host life cycle of the species, involving two obligatory teleost host fish species, small clupeids and large predatory fish. The most abundant parasite was O. cysticum which was found in 8 host fishes. In general most other species occurred in one host fish species only. The study confirms the predominance of otobothriid cestodes in the parasite fauna of tropical and subtropical teleost fish species. Since only Pseudotolithus senegalensis and Stromateus fiatola harboured flesh infestations, trypanorhynchids do not pose serious dangers to the marketability of most commercially important fish species in the area. The method of scanning electron microscopy was used to clarify the details of hooklet arrangement on the tentacular armature of some species for the first time.

Description: Commercial fish species from the east Nigerian coast were examined for external lesions and flesh parasitic infections that may affect their consumability. Altogether, 2 886 specimens from 43 species representing 34 genera were sampled. The occurrence of lymphocystis disease in the pleuronectiform Cynoglossus senegalensis is here reported for the first time from an African marine teleost. Other external lesions of fishes encountered were fin rot, granulomas, pseudotumours and ulcers with total prevalences not exceeding 1%; The following commercial fish species were infected by muscle parasites at the given prevalences: Cynoglossus browni (metacercariae, 18%, Capillaria spinosa eggs, 27%; Echinocephalus sinensis L3 larvae, 9%; Philometra beninensis, 27%); C. senegalensis (Kudoa sp., 10%; metacercariae, 87%); Pseudotolithus brachygnathus (Hysterothylacium sp. larvae, 2%); P. senegalensis (Poecilancistrum cf caryophyllum plerocercoid, 1%; Philometra beninensis, 1% P. typus (Kudoa sp., 3%); Synaptura cadenati (Echinocephalus sinensis, 12%); Stromateus fiatola (trypanorhynch plerocer-coid, 44%); Epinephelus aeneus (didymozoid trematode, 44%; Hysterothylacium sp. larvae, 6%). Capillaria and Echinocephalus, representing helminths with zoonotic potential, present low risks to publie health due to their low prevalences and the local methods of preparing fish for consumption. Apart from C. spinosa eggs in soles and trypanorhynch plerocercoids in S.fiatola, none of the other flesh parasites are likely to affect the market value of their hosts at the recorded levels of occurrence. Carcharhinid sharks influence the occurrence in the locality of most fesh-parasitic helminths for which they serve as definitive hosts. The absence of the third stage larvae of zoonotic Anisakidae common in marine fishes from many other parts of the world is related to the unavailability of suitable hosts. Compared to the results from most temperate locations where similar studies have been carried out, the present study shows remarkably low prevalences and diversity for external lesions and flesh parasites in West African marine fishes

Description: In April 1990, 488 marine fish belonging to 30 species from central Phillipine waters were examined for flesh parasitic infections that may affect their consumability. One species of hemirhamphids and 3 species of belonids harboured plerocercoids of Otobothrium penetrans Linton, 1907 (Proceedings of the U.S. National Museum33, 85–126). This is the first record of this parasite from Pacific fish species. The highest intensity of infection found was 8 in Tylosurus crocodilus. Most of the larvae were located between the dorsal spines of the vertebral column, only 32% were found in the fillets. Based on the present material we give a description of the plerocercoid stage of the species using scanning electron microscopy of the armature and morphometrical measurements. Comparison to results from earlier findings of O. penetrons by Linton (1907; 1924, Proceedings of the U.S. National Museum64, 1–114) and to O. kurisi by Shields (1985, International Journal for Parasitology15: 635–643) lead to the conclusion that the latter species is a synonym for O. penetrans.

Description: The infestation of Weddell seals and several fish species by the anisakid nematodes Contracaecum osculatum and C. radiatum was compared. Nematode numbers in Weddell seal stomachs ranged from 30 560 to 122 640. Third stage larvae from seals and fish were separated into a short and a long type. The short type was related to C. radiatum and the long type to C. osculatum. The short type was more abundant in pelagic fish species, whereas the long type prevailed in benthic fish species. Fish-feeding channichthyids Cryodraco antarcticus and Chionodraco myersi seemed to play an important role as paratenic hosts for the third stage larvae of both Contracaecum species. Different advantageous and detrimental features of a benthic versus a pelagic life cycle under high Antarctic ecological conditions are discussed. Varying abundance of the two nematode species in hosts may be controlled by differences in their life cycles, which follow either a pelagic or a benthic food web. Crucial importance is thus given to the local availability of pelagic versus benthic food resources for Weddell seals.

Description: Nicht leicht haben es die Vertreter einer wenig beschriebenen Terordnung, nach denen wir diesmal fragen. Birgt doch ihr Parasitendasein mit mehrfachem Wirtswechsel in den Weiten der Ozeane nicht wenige Gefahren.

Description: A total of 1956 fishes of 107 species from 3 regions of the Atlantic ocean were examined for larval cestodes and an identification key for larval cestodes of the order Trypanorhyncha is presented. Two species of pseudophyllid larvae were found in 5 out of 11 fish species (n=330) from the Weddell-Sea (Antarctic). Glandicephalus perfoliatus infested Chionodraco myersi (88 %), Cryodraco antarcticus (100 %), Pagetopsis maculatus (10 %) and Trematomus eulepidotus (12 %), while Diphyllobothrium sp. occurred only in Trematomus scotti (1,5 %). Nine different trypanorhynchid larval cestodes could be isolated from 14 out of 44 examined fish species (n= l120) from the Gulf of Guinea (Nigeria): Nybelinia dakari (Pomadasys peroteti (2,6 %)), Otobothrium cysticum (Arius latiscutatus (3,8); Caranx senegallus (40 %); Cynoponticus ferox (20 %); Psettias sebae (62,9 %); Pseudotolithus brachygnathus (8,6 %); P. elongatus (56 %); P. typus (19,4 %); Sphyraena guachancho (40 %)), Otobothrium dipsacum ( Petrocephalus bane (4,3 % ), Otobothrium sp. (Stroma teus fiatola (100 %)), Poecilancistrium caryophyllum (Pseudotolithus senegalensis (4,8 %)), Pseudogrillotia perelica nov. comb. (Caranx senegallus (81,8 %)), Pterobothrium sp. (Galeoides decadactylus (3,2 %)), Tetrarhynchobothriidae (Epinephelus aeneus (12,5 %)) and one unidentified trypanorhynchid larva from Galeoides decadactylus (3,2 %). Two tetraphyllid and eight trypanorhynchid larval cestodes were found in 12 out of 52 fish species (n=506) from the north-east Brazilian coast: Calli tetrarhynchus qracilis (Caranx crysos (25 %); Harengula clupeola (33,3 %); Oligoplites palometa (14,3 %); Opisthonema oglinum (40 %); Scomberomorus maculatus (28,6 %); Selene vomer (20 %)), Lacistorhvnchus sp. (Haemulon aurolineatum (9,1 %), Pseudupeneus maculatus (83,3 %); Scomberomorus maculatus (14,3 %)), Nybelinia sp. I (Haemulon plumieri (10 %); Pseudupeneus maculatus (20 %); Selene vomer (20 %)), Nybelinia sp. II (Pseudupeneus maculatus (10 %)), Nybelinia sp. III (Pseudupeneus maculatus (10 %)), Otobothrium cysticum (Scomberomorus maculatus (42,9 %)), Otobothrium dipsacum (Pseudupeneus maculatus (16,7 %)), Rhinebothrium sp. (Gobionellus oceanicus (15,4 %)), Scolex pleuronectis (Hyporhamphus unifasciatus (6,7 %)) and one unidentified trypanorhynchid larva from Lutjanus analis (16,7 %). Lacistorhynchus sp. is supposed to be a new species. Plerocercoids of Pseudophyllids, Tetraphyllids and Trypanorhynchs are the predominant cestode larvae in marine fishes. They are mainly found in the body cavity of their intermediate fish hosts. However, Trypanorhynchs of the families Grillotiidae, Gymnorhynchidae, Lacistorhynchidae, Otobothriidae and Pterobothriidae are the most frequent findings in the muscle. In the present study, three larval trypanorhynch cestodes (Lacistorhynchus sp. (Lacistorhynchidae); Otobothrium sp. and Poecilancistrium caryophyllum (Otobothriidae) could be found in the muscle of the fish examined. The occurrence of larval cestodes in different regions of the Atlantic ocean depends on the distribution of their final hosts. In polar regions larval Pseudophyllidea (final hosts: seals, whales) are the dominant order, while Trypanorhyncha (final hosts: sharks, rays) occur mainly in the tropics. In contrast, all 3 orders (Pseudophyllidea, Tetraphyllidea, Trypanorhyncha) can be found in the boreal zone of the Atlantic. The distribution of larval cestodes which are potentionally pathogenic for man is limited to the polar and boreal zones. However, they occur with low prevalences and cause only little thread to the public health. In the tropics, even the consumption of raw fish bears no risk, because all isolated larval cestodes belonged to the order Trypanorhyncha, which use sharks and rays as their final hosts.