Philometroides Yamaguti, 1935

Kirjusina, Muza, Paidere, Jana, Rubenina, Ilze, Kecko, Sanita, Bricis, Reinis, Mežaraupe, Ligita & Gavarane, Inese, 2023, Common Freshwater Fish Nematodes In Latvia, Acta Biologica Universitatis Daugavpiliensis (Sao Paulo, Brazil) 23 (2), pp. 189-206 : 197

Genus Philometroides Yamaguti, 1935

Philometroides cyprini (Ishii, 1931) Nakajima, 1970

Syn.: Philometra lusii Vismanis, 1962 , Philometroides lusiana Vismanis, 1966

Wide distributed and specific to host nematode in carp ponds and lakes. The intensity of infection can reach 100% in ponds and up to 80.0% in lakes ( Vismanis 1962, Vismanis 1964, Vismanis 1967, Vismanis 1967a, Vismanis 1967b, Vismanis 1972, Vismanis et al. 1989). Philometroides cyprini is considered to be an introduced species that is specific to common carp (Moravec et al. 2005). Gravid and subgravid females are spiralshaped under the scales; young fertilized females occur in the body cavity, while juveniles, males and unfertilized females are found mainly in the serosa of the swimbladder (between walls). P. cyprini has an annual indirect life cycle, in which the carp is the final host and various copepod species serve as intermediate hosts ( Schäperclaus 1979, Moravec 1994). Philometrids P. cyprini are pathogenic parasites for carp. Migrating juveniles cause inflammation of the swimbladder wall with mechanical damage to blood vessels. The movement of female nematodes to the tissues leads to the damage of muscle. Mass infestations can cause a philometroidosis disease in both cultured and wild fish ( Moravec & Cervinka 2005).

Philometroides sanguinea (Rudolphi, 1819) Rasheed, 1963

In the caudal fin (female) and swimbladder wall (male) of crucian carp from lakes this nematode was found in single specimens ( Kirjusina & Vismanis 2003). This nematode is specific to fishes of the genus Carassius . The first intermediate hosts are copepods Cyclops, Leptocyclops, Pachycyclops , Acanthocyclops , Macrocyclops , Mesocyclops , Megacyclops , Tropocyclops , Thermocyclops, Diaptomus, Neutrodiaptomus, Sinodiaptomus , which become infected by eating first-stage larvae that emerge either from the body of a female that has left the fish or with reproductive products fish, into the external environment ( Cakay 1957, Nakajima & Egusa 1977a, Nakajima & Egusa 1977 b, Nakajima & Egusa 1977c). The definitive host of Carassius becomes infected by eating infected crustaceans ( Wierzbicki 1958, Wierzbicki 1960, Ouk & Chun 1973, Moravec 1994, Williams et al. 2012). The distribution of hosts such as Macrocyclops , Megacyclops , Cyclops , Mesocyclops in Latvian freshwaters is described in sections P. rischta , P. ovata , C. lacustris .