RESUMO
Eurytrema coelomaticum is a digenean flatworm of ruminants that is the causative agent of eurytrematosis, a disease of veterinary health concern. Although modern techniques of morphological analysis have provided new insights about the morphology and anatomy of parasitic helminths, most studies on E. coelomaticum adults are based on conventional light microscopy. In the present study, a combined approach using brightfield, fluorescence, confocal and scanning electron microscopies (SEMs), together with the cryofracture technique, have updated morphological data on E. coelomaticum recovered from cattle in Rio de Janeiro State, Brazil. Light microscopy confirmed the presence of several structures present in the current description, such as suckers, pharynx, oesophagus, intestinal bifurcation and the cirrus-sac. Fluorescence stereomicroscopy revealed for the first time the cubic crystal protein inclusions in the forebody, which were further detailed by confocal and SEMs. Confocal microscopy provided detailed information of the muscular architecture associated with the attachment structures (suckers), digestive system (pharynx and oesophagus), egg-forming complex (ovary, Mehlis' gland and Laurer's canal) and male reproductive system, which are similar to those found in other digenean flukes. SEM images of cryofractured parasites showed mucus and developing eggs within uterine loops. It was demonstrated that the combination of advanced tools generated complementary information, confirming the importance of experimental morphology in parasitology. Therefore, the knowledge of the adult structural organization of E. coelomaticum was improved and this work has contributed to propose new morphological criteria to evaluate the effects of antiparasitic drugs on flukes of medical and veterinary importance.
Assuntos
Heterophyidae/anatomia & histologia , Heterophyidae/ultraestrutura , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Ovos , Feminino , Genitália/anatomia & histologia , Genitália/ultraestrutura , Masculino , Microscopia Confocal , Microscopia Eletrônica de Varredura , Platelmintos , Infecções por Trematódeos/veterináriaRESUMO
The complete life cycle of the trematode Ascocotyle (Phagicola) longa (Digenea: Heterophyidae) is elucidated by natural observation validated by experimental infections. The natural first intermediate host of A. (P.) longa, an agent of human heterophyiasis in Brazil, is the cochliopid snail Heleobia australis (new first intermediate host). Metacercariae were found encysted in the body musculature, heart, stomach, liver, kidney, spleen, gonads and mesentery of mullets Mugil liza. Hamsters Mesocricetus auratus were experimentally infected with metacercariae of A. (P.) longa obtained from the mullets, and the adults recovered were used to infect the snails H. australis. Rediae and cercariae of A. (P.) longa are described for the first time. The ultrastructure of the tegument of A. (P.) longa shows a change in spination pattern from the cercaria with single-pointed spines to the metacercaria and adult with multipointed, brush-shaped spines. The life cycle of A. (P.) longa is related to estuaries and coastal lagoons where the recruitment of mugilid juveniles occurs. The high prevalence (100%) of A. (P.) longa encysted in the mullets examined within the urban area of Rio de Janeiro indicates the potentially great public health impact of the consumption of raw mullets.
Assuntos
Heterophyidae/crescimento & desenvolvimento , Estágios do Ciclo de Vida , Estruturas Animais/parasitologia , Animais , Brasil , Cricetinae , Doenças Transmitidas por Alimentos/parasitologia , Heterophyidae/ultraestrutura , Humanos , Mesocricetus/parasitologia , Microscopia , Microscopia Eletrônica de Varredura , Smegmamorpha/parasitologia , Caramujos/parasitologiaRESUMO
The life history of the trematode Pygidiopsis macrostomum Travassos, 1928 is described for the first time. Rediae and cercariae were obtained from naturally infected snails Heleobia australis (d Orbigny), a new first intermediate host. Metacercariae were found encysted in the mesenteries of three naturally infected guppies, Phalloptychus januarius (Hensel), Jenynsia multidentata (Jenyns) (new host records) and Poecilia vivipara Bloch and Schneider. Experimental infections were successfully completed in the intermediate hosts H. australis and Poe. vivipara reared in the laboratory and hamsters Mesocricetus auratus Waterhouse were utilised as a definitive host.
Assuntos
Heterophyidae/crescimento & desenvolvimento , Estágios do Ciclo de Vida/fisiologia , Mesocricetus/parasitologia , Poecilia/parasitologia , Caramujos/parasitologia , Animais , Cricetinae , Heterophyidae/ultraestrutura , Microscopia Eletrônica de Varredura , Poecilia/classificação , Estações do Ano , Caramujos/classificaçãoRESUMO
The life history of the trematode Pygidiopsis macrostomum Travassos, 1928 is described for the first time. Rediae and cercariae were obtained from naturally infected snails Heleobia australis (d´Orbigny), a new first intermediate host. Metacercariae were found encysted in the mesenteries of three naturally infected guppies, Phalloptychus januarius (Hensel), Jenynsia multidentata (Jenyns) (new host records) and Poecilia vivipara Bloch and Schneider. Experimental infections were successfully completed in the intermediate hosts H. australis and Poe. vivipara reared in the laboratory and hamsters Mesocricetus auratus Waterhouse were utilised as a definitive host.
Assuntos
Animais , Cricetinae , Heterophyidae/crescimento & desenvolvimento , Estágios do Ciclo de Vida/fisiologia , Mesocricetus/parasitologia , Poecilia/parasitologia , Caramujos/parasitologia , Heterophyidae/ultraestrutura , Microscopia Eletrônica de Varredura , Poecilia/classificação , Estações do Ano , Caramujos/classificaçãoRESUMO
The heterophyid trematode Ascocotyle (Ascocotyle) felippei Travassos, 1928, is redescribed and new data on its life cycle are provided, based on types and metacercariae found in the heart bulb and gills of naturally infected guppies, Poecilia vivipara (new fish intermediate host), from a coastal lagoon in Rio de Janeiro, Brazil. Examination of the type and all voucher specimens of A. (A.) felippei collected by Travassos in the type host and locality in Brazil has shown that they possess only 32 (16 + 16) circumoral spines, rather than 36 (18 + 18) spines as previously reported. Based on the identical number and arrangement of circumoral spines, shape of the body, the presence of a long preoral lobe and posterior muscular prolongation of the oral sucker, short and wide ceca, a simple gonotyl lacking refractile bodies, and the site of infection of metacercariae (predominantly heart bulb), A. (A.) puertoricensis Price, 1932 and A. (A.) tenuicollis Price, 1935, are proposed as new synonyms of A. (A.) felippei.
Assuntos
Doenças dos Peixes/parasitologia , Heterophyidae/anatomia & histologia , Poecilia/parasitologia , Infecções por Trematódeos/parasitologia , Animais , Doenças das Aves/parasitologia , Aves , Brasil , Heterophyidae/crescimento & desenvolvimento , Heterophyidae/ultraestrutura , Microscopia Eletrônica de Varredura/veterinária , Microscopia de Vídeo/veterináriaRESUMO
Trematodes found in the intestines of dogs from Chillan, VIII region of Chile, were studied. The species identified was Phagicola longa, a fluke of the Heterophyidae family, parasites of fish-eating birds or mammals in several countries. P. longa is very similar to P. arnaldoi, a species described in dogs from South America. The number of vitelline follicles and the distribution of cuticular spines are the only distinctive features for the two species. However, many authors report the same number of vitelline follicles for P. arnaldoi and P. longa. Furthermore, the distribution of cuticular spines is very similar. P. longa has a small area devoid of spines when compared to P. arnaldoi but a wide variability of this generic character in the Heterophyidae was observed. As previously reported, P. arnaldoi could be a recent synonym of P. longa, which is the only species of Phagicola that can be found in South American dogs. This is in agreement with the study of metacercariae found in Mugilidae, the intermediate hosts of Phagicola, from American waters in which P. longa is the only species found. The authors emphasize the finding of this trematode in dogs, since it could possibly cause also human infection.