RESUMO

The intestinal trematode, Haplorchis taichui (Nishigori, 1924), is an important in public health that causes infection in humans and animals especially in Asia and in parts of Africa and the Americas. Haplorchis taitui metacercariae were found in the gills of Cyprinion macrostomus (Heckel) and Capoeta barroisi persica (Karaman) collected from the Shapour River. Morphological excysted metacercariae were identified as wet mounts under a stereomicroscope. Then, the samples were subjected to molecular analysis. The result showed that 69% of examined fish (n=30) were diagnosed infected with encysted metacercariae in gills. The mean intensity was 8.3±16.9 parasites per fish. The morphometrical values agree with the findings of other studies with the small differences and polymerase chain reaction product length and nucleotide sequence analysis of 18S ribosomal deoxyribonucleic acid gene showed a similarity of over 99% between the specimens and the Haplorchis taichui (Nishigori, 1924) recorded in GenBank.(AU)

O trematódeo intestinal, Haplorchis taichui (Nishigori, 1924), é importante na saúde pública que causa infecção em humanos e animais, especialmente na Ásia e em partes da África e das Américas. Haplorchis taitui metacercariae foram encontradas nas brânquias de Cyprinion macrostomus (Heckel) e Capoeta barroisi pérsica (Karaman) coletadas no rio Shapour. Metacercárias foram identificadas microscopicamente sob um estereomicroscópio. Em seguida, as amostras foram submetidas à análise molecular. O resultado mostrou que 69% dos peixes examinados (n=30) foram diagnosticados infectados com metacercárias encistadas em brânquias. A intensidade média foi de 8,3±16,9 parasitas por peixe. Os valores morfométricos concordam com os achados de outros estudos com as pequenas diferenças e o comprimento do produto da reação em cadeia da polimerase e a análise da sequência nucleotídica do gene do ácido desoxirribonucleico ribossômico 18S mostraram uma similaridade de mais de 99% entre as amostras e o Haplorchis taichui (Nishigori, 1924) registrado no GenBank.(AU)

El trematodo intestinal, Haplorchis taichui (Nishigori, 1924), es importante en la salud pública que causa infección en humanos y animales, especialmente em Asia y em partes de África y América. Se encontraron Haplorchis taitui metacercariae en las branquias de Cyprinion macrostomus (Heckel) y Capoeta barroisi persica (Karaman) colectadas del río Shapour. Las metacercarias se identificaron bajo un microscopio estereoscópico. Luego, las muestras fueron sometidas a análisis molecular. El resultado mostró que el 69% de los peces examinados (n=30) fueron diagnosticados infectados con metacercarias enquistadas en las branquias. La intensidad media fue de 8.3±16.9 parásitos por pece. Los valores morfométricos concuerdan con los hallazgos de otros estudios con las pequeñas diferencias y la longitud del producto de reacción en cadena de la polimerasa y el análisis de la secuencia de nucleótidos del gen del ácido desoxirribonucleico ribosómico 18S mostró una similitud de más del 99% entre las muestras y el Haplorchis taichui (Nishigori, 1924) registrado en GenBank.(AU)

Assuntos

RESUMO

The intestinal trematode, Haplorchis taichui (Nishigori, 1924), is an important in public health that causes infection in humans and animals especially in Asia and in parts of Africa and the Americas. Haplorchis taitui metacercariae were found in the gills of Cyprinion macrostomus (Heckel) and Capoeta barroisi persica (Karaman) collected from the Shapour River. Morphological excysted metacercariae were identified as wet mounts under a stereomicroscope. Then, the samples were subjected to molecular analysis. The result showed that 69% of examined fish (n=30) were diagnosed infected with encysted metacercariae in gills. The mean intensity was 8.3±16.9 parasites per fish. The morphometrical values agree with the findings of other studies with the small differences and polymerase chain reaction product length and nucleotide sequence analysis of 18S ribosomal deoxyribonucleic acid gene showed a similarity of over 99% between the specimens and the Haplorchis taichui (Nishigori, 1924) recorded in GenBank.

O trematódeo intestinal, Haplorchis taichui (Nishigori, 1924), é importante na saúde pública que causa infecção em humanos e animais, especialmente na Ásia e em partes da África e das Américas. Haplorchis taitui metacercariae foram encontradas nas brânquias de Cyprinion macrostomus (Heckel) e Capoeta barroisi pérsica (Karaman) coletadas no rio Shapour. Metacercárias foram identificadas microscopicamente sob um estereomicroscópio. Em seguida, as amostras foram submetidas à análise molecular. O resultado mostrou que 69% dos peixes examinados (n=30) foram diagnosticados infectados com metacercárias encistadas em brânquias. A intensidade média foi de 8,3±16,9 parasitas por peixe. Os valores morfométricos concordam com os achados de outros estudos com as pequenas diferenças e o comprimento do produto da reação em cadeia da polimerase e a análise da sequência nucleotídica do gene do ácido desoxirribonucleico ribossômico 18S mostraram uma similaridade de mais de 99% entre as amostras e o Haplorchis taichui (Nishigori, 1924) registrado no GenBank.

El trematodo intestinal, Haplorchis taichui (Nishigori, 1924), es importante en la salud pública que causa infección en humanos y animales, especialmente em Asia y em partes de África y América. Se encontraron Haplorchis taitui metacercariae en las branquias de Cyprinion macrostomus (Heckel) y Capoeta barroisi persica (Karaman) colectadas del río Shapour. Las metacercarias se identificaron bajo un microscopio estereoscópico. Luego, las muestras fueron sometidas a análisis molecular. El resultado mostró que el 69% de los peces examinados (n=30) fueron diagnosticados infectados con metacercarias enquistadas en las branquias. La intensidad media fue de 8.3±16.9 parásitos por pece. Los valores morfométricos concuerdan con los hallazgos de otros estudios con las pequeñas diferencias y la longitud del producto de reacción en cadena de la polimerasa y el análisis de la secuencia de nucleótidos del gen del ácido desoxirribonucleico ribosómico 18S mostró una similitud de más del 99% entre las muestras y el Haplorchis taichui (Nishigori, 1924) registrado en GenBank.

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RESUMO

We report for the first time the infection of dolphins with Ascocotyle longa found in the intestines of three different species, Sotalia guianensis, Steno bredanensis, and Tursiops truncatus gephyreus, which were found washed ashore along the southeastern and southern Brazilian coast. The worms were identified based on morphological and molecular data using the 28S rDNA gene and the COI gene. Specimens of A. longa from the pinniped Otaria flavescens were also analyzed. As the first isolation of A. longa from cetaceans, the present study increases the distribution area and range of definitive hosts of this trematode, and provides new molecular data to complement the phylogeny of the group in future studies, thus contributing to the scientific knowledge of this potentially zoonotic parasite.

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RESUMO

This is the first study that used species-specific DNA primers to confirm the presence of the heterophyid Ascocotyle (Phagicola) longa Ransom, 1920 in its first intermediate host. The larval stages (rediae and cercariae) of this parasite were morphologically and genetically identified in the gonad of the intertidal mud snail Heleobia australis (d'Orbigny, 1835) (Cochliopidae) in the Bahía Blanca estuary, Argentina. In addition, we asked whether the prevalence in H. australis varied between seasons. Mullets - the second intermediate host of this heterophyid - migrate in estuaries during the warmer seasons and it is expected that piscivorous birds and mammals - the definitive hosts - prey more intensively on this species at those times. Thus, the number of parasite eggs released into the tidal flat within their feces should be higher, thereby increasing the ingestion of the parasite by H. australis.We therefore expected a higher prevalence of A. (P.) longa in H. australis in the Bahía Blanca estuary during spring and summer than autumn and winter. We found that 16 out of 2,744 specimens of H. australis had been infected with A. (P.) longa (total prevalence of 0.58%). Nonetheless, the prevalence showed no significant variation between seasons. Hence, we discuss an alternative scenario where the lack of seasonal changes might be mostly related to the permanent residence of definitive hosts in the estuary and not to the seasonal recruitment of mullets. Finally, we highlight the need for more experimental and comparative approaches in order to understand the diagnosis and geographical distribution of this worldwide heterophyid.

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RESUMO

Parasites can invade new ecosystems if they are introduced with their native hosts or if they successfully infect and colonise new hosts upon arrival. Here, we ask to what extent an introduced parasite demonstrates specialisation among novel host species. Infection surveys across three field sites in Gatun Lake, Panama, revealed that the invasive peacock bass, Cichla monoculus, was more commonly infected by the introduced trematode parasite Centrocestus formosanus than were three other common cichlid fishes. Laboratory infection experiments were conducted to determine whether parasitism might be driven by differential encounter/exposure to parasites or by differential infection susceptibility/preference across different host species. These experiments were performed by controlling for parasite exposure in single host (compatibility) experiments and in mixed host (preference) experiments. In all cases, the peacock bass exhibited higher infection rates with viable metacercariae relative to the other potential fish hosts. Our experiments thus support that an introduced generalist parasite shows apparent specialisation on a specific novel host. Further studies are needed to determine whether these patterns of specialisation are the result of local adaptation following invasion by the parasite.

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RESUMO

We describe a new heterophyid species, Ascocotyle (Ascocotyle) patagoniensis n. sp., based on specimens collected from the intestines of the South American sea lion Otaria flavescens from Patagonia (Argentina). Ascocotyle (A.) patagoniensis n. sp. is distinguished from the other species of the subgenus by the number of circumoral spines, which are arranged in 2 rows of 18 to 23. The new species also differs from the other species in having a gonotyl without papillae. The specimens exhibited the widest seminal receptacle described for a species of this subgenus. Species of the subgenus Ascocotyle usually infect fish-eating birds or mammals in freshwater or brackish habitats. Ascocotyle (A.) patagoniensis n. sp. is the first species of the subgenus described from a marine mammal. However, no metacercariae of Ascocotyle spp. were found in 542 marine teleosts from 20 species collected in the same locality. The life cycle of the marine species from the Ascocotyle -complex infecting pinnipeds remains elusive.

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RESUMO

In the late 1960s, Melanoides tuberculatus snails were introduced in Brazil from North/East Africa and Southeast Asia. The first records of specimens infected with cercariae were registered in Rio de Janeiro State in 2001. The present study reports the occurrence of M. tuberculatus infected with larval trematodes in Rio de Janeiro City. Bottom sediment was collected with dip nets and sieved through 0.25 inch-mesh screening. Snails were transported to the laboratory in vials with stream water, then measured and individually isolated in glass vials with distilled water. They were exposed to artificial light and temperature to induce cercarial emergence. The most actively emerging cercariae were processed by differential staining and silver nitrate impregnation methods. Negative snails were subsequently dissected. Approximately 700 snails were collected. Snail total lengths ranged from 1.2 to 3.3 cm. The prevalence rate was 15.76% although 53.76% of the snails were found infected in one of the sites. Infected snails were infected with rediae and pleurolophocercous cercariae. Cercarial morphology and chaetotaxy were consistent with those of the family Heterophyidae mostly due to the presence of median dorsal and ventral fins on the tail and the absence of CI dorsal sensory receptors.

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RESUMO

No final da década de 60, caramujos da espécie Melanoides tuberculatus, originários do nordeste africano e sudeste asiático, foram introduzidos no Brasil. Os primeiros registros de espécimes infectados com cercárias foram feitos no Estado do Rio de Janeiro em 2001. O presente estudo relata a ocorrência de M. tuberculatus infectados com larvas de trematódeos na cidade do Rio de Janeiro. O sedimento dos criadouros foi coletado e peneirado através de malhas de 0,25 polegadas. Os caramujos foram transportados em recipientes com água dos criadouros, sendo medidos e posteriormente individualizados. Eles foram expostos à luz e temperatura artificiais para induzir a emergência cercariana. As cercárias mais ativas foram processadas pelos métodos de coloração diferencial e de impregnação por nitrato de prata. Os caramujos negativos foram subsequentemente dissecados. Aproximadamente 700 caramujos foram coletados. Seu comprimento variou de 1,2 a 3,3 cm. A taxa de prevalência foi de 15,76% apesar de 53,76% dos caramujos estarem infectados em uma das áreas. Os caramujos estavam infectados com rédias e cercárias do tipo pleurolofocerca. A morfologia e a quetotaxia cercarianas foram compatíveis com as da família Heterophyidae principalmente devido à presença de nadadeiras medianas dorsais e ventrais e à ausência de receptores sensoriais CI dorsais.

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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.

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RESUMO

Two species of heterophyid cercariae, cercaria of Haplorchis taichui and Haplorchis pumilio are obtained from Thiara tuberculata from Visakhapatnam, India. This is the first report of cercariae of both the parasites from India. The characteristic features of H. taichui cercaria are the presence of two sets--one set of lateral and other dorsoventral cuadal finfolds, 15 acicular spines in three alternating rows and seven pairs of lobed penetration glands arranged in two longitudinal rows. H. pumilio cercaria is characterized by the presence of two sets of caudal finfolds, 15 acicular spines in three alternating rows and seven pairs of voluminous unicellular penetration glands.

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