ABSTRACT
Annecy Lake is a well-known focus of human cercarial dermatitis in France. Identification of the parasites, however, was not performed in the past. Previous studies suspected two species, Trichobilharzia franki and Trichobilharzia regenti, based on the presence of parasites in mallards and/or morphological identification of snails emitting ocellate furcocercariae. Following a standardized molecular approach, we studied snails and furcocercariae and compared their haplotypes with those deposited in GenBank. The selected markers were the second internal transcribed spacer ITS-2 for the snails and ITS-2 and D2 domain of the ribosomal DNA for the parasites. Our results confirm the presence of T. franki and T. regenti and two probable new species that could be potential agents of cercarial dermatitis. All the snails emitting the ocellate furcocercariae belong to the same species identified as Radix peregra (=Radix ovata = Radix balthica). Parasite-host relationships between species of the genus Trichobilharzia and snails of the genus Radix do not seem to be as specific as supposed previously.
Subject(s)
Schistosomatidae/genetics , Schistosomiasis/parasitology , Animals , Bird Diseases/parasitology , Ducks/parasitology , France/epidemiology , Fresh Water , Genetic Markers , Phylogeny , Schistosomiasis/epidemiology , Snails/parasitologyABSTRACT
In 2005, we dissected 102 wildfowl from the Czech Republic and 73 wildfowl from Poland including representatives of Anseriformes, Gruiformes and Gaviiformes. Schistosome infection was found in a total of 21 (29%) and 23 (23%) birds from Poland and the Czech Republic, respectively. All infected birds belonged to the order Anseriformes. The prevalences of nasal and visceral species were, respectively, 22% and 16% in Poland and 6% and 19% in the Czech Republic. Four species of schistosomes were found: Bilharziella polonica Kowalewski, 1895, Trichobilharzia regenti Horák, Koláfová et Dvorák, 1998, T. szidati Neuhaus, 1952, and an undetermined schistosome from the intestinal wall of Anas penelope L. The finding of T. szidati represents the first record of the parasite from natural final host since the species description.
Subject(s)
Animals, Wild/parasitology , Bird Diseases/parasitology , Schistosomatidae/classification , Schistosomatidae/isolation & purification , Trematode Infections/veterinary , Animals , Birds , Czech Republic/epidemiology , DNA, Helminth/chemistry , DNA, Helminth/genetics , DNA, Ribosomal Spacer/chemistry , DNA, Ribosomal Spacer/genetics , Molecular Sequence Data , Phylogeny , Poland/epidemiology , Prevalence , Schistosomatidae/genetics , Sequence Analysis, DNA , Sequence Homology, Nucleic Acid , Trematode Infections/epidemiologyABSTRACT
The complete mitochondrial (mt) genome of the neuropathogenic bird schistosome Trichobilharzia regenti was fully sequenced in order to develop molecular markers for future diagnostic, molecular ecological, population, and phylogenetic studies. The genome was 14,838 bp in length, with a 68.4% AT bias in protein coding regions. A repeat element (3 x 184 bp) between trnV and trnW distinguished a single short noncoding region. As 9 of 14 genera of schistosomes parasitize birds, future characterization of their mt genomes is desirable for species-specific and strain- or population-specific diagnostic markers; this concerns not only the nasal representatives, e.g., T. regenti characterized in this study, but also numerous species within the predominant group of visceral (blood dwelling) bird schistosomes.
Subject(s)
DNA, Helminth/chemistry , DNA, Mitochondrial/chemistry , Genome, Helminth/genetics , Schistosomatidae/genetics , Animals , Base Sequence , Bird Diseases/parasitology , Birds , Chromosome Mapping/veterinary , Codon/chemistry , Conserved Sequence , DNA Primers/chemistry , Dermatitis/parasitology , Dermatitis/veterinary , Molecular Sequence Data , Nucleic Acid Conformation , Phylogeny , RNA, Helminth/chemistry , RNA, Transfer/chemistry , Schistosomatidae/classification , Sequence Alignment/veterinary , Skin Diseases, Parasitic/parasitology , Skin Diseases, Parasitic/veterinary , Tandem Repeat Sequences , Trematode Infections/parasitology , Trematode Infections/veterinaryABSTRACT
In Iceland, the examination of whooper swans (Cygnus cygnus L.) viscera resulted in the detection of adult digenean flukes of the family Schistosomatidae. The mature worms occurring in the blood vessels of the large intestine and mesenterium caused vascular lesions, around the eggs deposited in the intestinal mucosa and liver granulomatous reactions developed. The morphology of the isolated schistosomes shows certain similarity with the flukes of the genus Trichobilharzia; in males reduced gynecophoral canal, and on both sexes both suckers and spatulate ends are present. However, the Icelandic flukes possess other morphological features which are distinct from the genus: the point of caecal reunion in males takes place posterior to gynecophoral canal and the genital pore is behind acetabulum and anterior to caecal reunion. In order to evaluate the identity of Icelandic schistosomes, sequencing of ITS region of DNA was performed, and the obtained sequence was deposited in GenBank under the accession no. DQ067561. Following phylogenetic analysis of relationship between the sequence of Icelandic flukes and database sequences of other bird schistosome genera (Trichobilharzia, Gigantobilharzia and Dendritobilharzia) showed different position of Icelandic worms in the phylogenetic tree. In conclusion, our study revealed new genus and species of schistosome flukes--Allobilharzia visceralis gen. et sp. n.
Subject(s)
Anseriformes/parasitology , Bird Diseases/parasitology , Schistosoma/classification , Schistosomiasis/veterinary , Animals , Anseriformes/anatomy & histology , DNA, Ribosomal/genetics , Feces/parasitology , Female , Iceland , Male , Molecular Sequence Data , Parasite Egg Count , Phylogeny , Polymerase Chain Reaction , Schistosoma/anatomy & histology , Schistosoma/genetics , Schistosoma/isolation & purification , Schistosomiasis/parasitologyABSTRACT
In Central Europe, the adults of nasal bird schistosomes of the genus Trichobilharzia have only been reported from experimental infections. Our work confirmed a relatively high prevalence of these parasites in wild anatid birds in the Czech Republic. The isolated miracidia were used to infect the Radix peregra (an autochtonous snail species) which proved to be a susceptible intermediate host. Subsequently, the emerged cercariae penetrated the skin of domestic ducks and adults were found in the nasal mucosa. It can be concluded that nasal bird schistosomes occur in the Czech fauna and are able to complete their life cycle under the conditions found in Central Europe.
