ABSTRACT
The presence of metacercariae and adults of the trematode Pseudamphistomum truncatum in roach and mink, respectively, was recorded in Lake Fure North of Copenhagen, Denmark. This zoonotic digenean opisthorchiid represents a threat to humans due to its ability to infect the biliary system following ingestion of inadequately processed infected fish. Therefore precise species identification of infective metacercariae in fish used for human consumption is essential. Due to the relatively limited information on metacercarial identity obtained by morphometric studies a series of molecular techniques were used to link the larval parasite in fish with the un-equivocally diagnosed adults in the biliary system of the mink. By the use of carefully selected polymerase chain reaction (PCR) primers and subsequent sequencing of the ITS region from both metacercariae and adults full sequence identity of both metacercariae and adults were confirmed. The presence of this parasitosis in fish from a lake used for both commercial and recreational fisheries call for hygienic alerts in order to prevent accidental human infection with this opisthorchiid.
Subject(s)
Cyprinidae/parasitology , Fish Diseases/parasitology , Life Cycle Stages , Mink/parasitology , Opisthorchidae , Trematode Infections/veterinary , Animals , Base Sequence , Bile Ducts/parasitology , DNA, Ribosomal Spacer/genetics , Molecular Sequence Data , Opisthorchidae/anatomy & histology , Opisthorchidae/genetics , Opisthorchidae/growth & development , Phylogeny , Sequence Alignment , Sequence Homology, Nucleic Acid , Trematode Infections/parasitologyABSTRACT
Parafossarulus striatulus, Pseudorasbora parva and brood ducks are involved in the lifecycle of Metorchis orientalis. Natural nidi of M. orientalis are confirmed in Huaihe River Basin.
Subject(s)
Opisthorchidae/growth & development , Rivers/parasitology , Animals , China , Environmental Monitoring , Opisthorchidae/isolation & purificationABSTRACT
In order to observe the infectivity, growth and development and adult morphology of Metorchis orientalis, a total of 40 chicks were experimentally infected with 100 metacercariae respectively, collected from Pseudorasbora parva. The worms of various developmental stages were recovered from chicks at 1.5, 3, 5, 7, 9, 11, 14 and 21 days after infection, and they were prepared for morphological observations and measurements. All of the worms were found in the gallbladders of chicks, and their recovery rate was 32% in average. The growth of the body was rapid from 9 to 11 days after infection. The genital primordia appeared in 1.5 and 3-day old worms, and ovary and testes were first observed in 5-day old worms. Thereafter, genital organs gradually matured and completed up to 11 days after infection. The adult worm was leaf-like, and possessed a convoluted tubular seminal vesicle, an ovoid ovary, a sac-like seminal receptacle, 2 lobed-testes and follicular vitellaria. Eggs were 31.9 x 15.3 microns in average size, ellipsoid to elliptical in shape and possessed abopercular thickenings. From the above results, it is concluded that M. orientalis grows in sigmoid pattern in chicks, and their genital organs fully mature between days 9 and 11. It is also confirmed that a chick is a new definitive host of M. orientalis.
