RESUMO

The Amazon prawn or Macrobrachium amazonicum (Heller, 1862) is widely distributed in South America, occurring in the Orinoco and Amazon rivers, and forms an important source of income for riverside families. This prawn hosts crustacean ectoparasites of the genus Probopyrus (Giard & Bonnier, 1888) (Bopyridae) that infest its gill cavity. The aim of the present study was to report new occurrences of Probopyrus in Amazon prawns caught in the Amazon River. Macrobrachium amazonicum prawns were collected between May 2017 and April 2018, and again from July 2021 to May 2022 in the regions of Ilha de Santana and Rio Mazagão, state of Amapá, Brazil. Among the 5,179 prawn specimens caught, 133 were parasitized by the ectoparasites Probopyrus pandalicola (Packard, 1879), Probopyrus bithynis (Richardson, 1904), Probopyrus floridensis (Richardson, 1904) and Probopyrus palaemoni (Lemos de Castro & Brasil Lima, 1974). These occurrences of P. floridensis and P. palaemoni in M. amazonicum were the first records of this on the northern coast of Brazil. These four ectoparasites are not limited to specific host species or genera, as observed in this study, which reports four species of Probopyrus infesting M. amazonicum.

Assuntos

RESUMO

Bopyrid isopods of the genus Probopyrus are well-known parasites of freshwater prawns of the genus Macrobrachium. The parasitism of coastal populations of Macrobrachium amazonicum by Probopyrus bithynis, for example, has been documented since the late 1980s. Despite this, molecular data on different populations are not available for any Probopyrus species. The present study is the first to describe Probopyrus populations from distinct regions of the Amazon basin based on sequences of two genes, the mitochondrial cytochrome oxidase C subunit I (COI) and the nuclear 18S ribosomal DNA (18S rDNA) gene. The analyses indicated the presence of two Probopyrus species, each parasitizing either the coastal or the inland populations of M. amazonicum. The results indicated the potential use of the COI barcode for the identification of Probopyrus species. We discuss the potential implications of the findings for the taxonomy of Probopyrus bithynis and other species of the genus Probopyrus.

Assuntos

RESUMO

Parasites may affect host demographic characteristics because they can directly or indirectly cause the death of their hosts and/or influence their reproduction. Parasitism is therefore recognized as a factor that influences the composition and structure of populations and communities. One of these behaviours is the compensatory response: the host can compensate for the parasite losses effect, modifying the reproductive effort to enhance fitness. Ovigerus female Palaemonetes argentinus was collected and sorted into two groups according to the degree of development of their embryos: newly spawned embryos and embryos ready to hatch. The number of embryos and their dry weight for each female were determined. All parts of the female body were checked for parasites. The females of P. argentinus were parasitized by Microphalus szidati. We found that parasitized females produce more embryos but had more egg loss during development and the percentage of embryonic loss was higher in the parasitized females than in non-parasitized. Parasitized females produced lighter eggs than those from uninfected females. This supports the compensatory reproduction hypothesis suggested for this species. Parasitism can change life history traits in a way that fecundity can be compensated; this co-evolution between host and parasites will be population or context dependent. Parasites are a functional part of any ecosystem and as our results show, deleting parasites in life history traits and reproduction studies in free living organisms could lead to an incomplete picture of the true processes that happen in nature.

Assuntos

RESUMO

The present study describes, for the first time, histopathological alterations in the gills of Macrobrachium amazonicum caused by infestation of Probopyrus bithynis (Isopoda: Bopyridae). In every case (100%), the infestation by P. bithynis was by a single pair of parasites (male and female) and occurred in the right or left side of the branchial chamber; the gill structures were visibly compressed due to the presence of parasites. The gills of M. amazonicum parasitized by P. bithynis exhibited a chronic inflammatory response, with the presence of edema, greater quantities of hemocytes, necrosis, epithelial cell hyperplasia, rupture of the pillar cells at the ends of the gill lamellae, desquamation of the cuticle, lamellar fusion and rupture of the lamellar epithelium. Tissue lesions were found in the histological sections of the gills of the parasitized M. amazonicum. Structural alterations in the branchial chamber of the hosts caused by the presence of P. bithynis can lead to physiological changes that can impair host respiratory performance. Finally, histopathological alterations in the branchial chamber of hosts suggest that P. bithynis feed directly on the gill tissues of this shrimp.

Assuntos

RESUMO

The microphallids Microphallus szidati and Levinseniella cruzi parasitized at least three crustacean species as second intermediate host in Mar Chiquita coastal lagoon: the crabs Neohelice granulata and Cyrtograpsus angulatus and the grass shrimp Palaemonetes argentinus. Palaemonetes argentinus acts as host for both metacercariae in brackish and freshwater environments; however the seasonal variations of these digeneans in freshwater habitats remain unexplored. The aim of the present study was to analyze the seasonal dynamic of the larval digenean populations parasitizing P. argentinus in a lentic environment. From the total sample of 600 P. argentinus collected seasonally, 28.370 and 194 metacercariae of M. szidati and L. cruzi, respectively, were recovered. Microphallus szidati was characterized by high prevalence, 100% in all seasons. In contrast, L. cruzi presented low prevalence values, which increased towards summer. The two species of digeneans exhibit seasonal fluctuations in intensity of infection, which was related to host size. Temporal variation of larval digenean assemblage in the crustacean host is probably associated with the presence of the other hosts included in their life cycles. The high values of prevalence found for M. szidati in Nahuel Rucá lagoon suggest that P. argentinus could favor the contact between the larval digenean and the definitive hosts, establishing the presence of M. szidati also in freshwater environments and, thus, increasing the presence of the parasite in different areas of Mar Chiquita coastal lagoon.

Assuntos

RESUMO

Se determinó la presencia de Giardia intestinalis y Cryptospodidium parvum, bacteriófagos de Escherichia coli y organismos indicadores de contaminación (OIC), en muestras de camarones para el consumo humano comercializados en el estado Zulia. Los parásitos se concentraron a partir de sistemas digestivos de pools de camarones por la técnica de formol-éter y se cuantificaron por inmunofluorescencia directa. La concentración de los bacteriófagos de E. coli F+ y los OIC se evaluó por técnicas estándar. En este trabajo se detectó la presencia de G. intestinalis, C. parvum, bacteriófagos y E. coli en camarones comercializados en el estado Zulia que cumplían los criterios de la normativa venezolana de calidad sanitaria e inocuidad. Del total de muestras analizadas el 91,5% fueron positivas para G. intestinalis (promedio: 36,6 quistes/100g), 95,3% para C. parvum (promedio: 32,8 ooquistes/100g), 100% para los bacteriófagos de E coli F+ (promedio de 2,8 x 103 UFP/100 g) y 71,5% para E. coli (promedio de 4,3 x 104 NMP/g). Los resultados obtenidos indican que los camarones pueden convertirse en un vehículo para la transmisión de patógenos al hombre y dejan en evidencia la necesidad de la inclusión de un parámetro parasitológico y viral en el control de la calidad microbiológica de estos productos alimenticios.

The presence of G. intestinalis and C. parvum, E. coli F+ bacteriophages and fecal pollution indicator organisms was determined in shrimp for human consumption marketed in the State of Zulia. Parasites were concentrated from the digestive systems of shrimp pools, detected by formalin-ether and quantified by direct immunofluorescence. E. coli F + bacteriophage and pollution indicator organism concentrations were determined by standard techniques. In this work, G. intestinalis, C. parvum, E. coli F + bacteriophages and E. coli were detected in shrimp for human consumption marketed in the State of Zulia that met the quality criteria of Venezuelan health and safety regulations. 91.5% of the samples analyzed were positive for G. intestinalis (average: 36.6 cyst/100g), 95.3% for C parvum (average: 32.8 oocyst/100g), 100% for E coli F + bacteriophages (average: 2.8 x 103 FPFU/100g) and 71.5% for E. coli (average: 4.3 x 104 MPN/g). Results of this research indicate that shrimp can become a vehicle for transmitting pathogens to humans and demonstrate the need for including a parasitic and viral parameter in microbiological quality control for seafood.

Assuntos

RESUMO

We surveyed protozoan and metazoan parasites as well as white spot syndrome virus (WSSV) and infectious hypodermal hematopoietic necrosis virus (IHHNV) in white shrimp Litopenaeus setiferus and the palaemonid prawn Macrobrachium acanthurus native to the lower Jamapa River region of Veracruz, Mexico. The presence of parasites and the infection parameters were evaluated in 113 palaemonid prawns collected during the northwind (n = 45), rainy (n = 38) and dry seasons (n = 30) between October 2007 and July 2008, and in 91 shrimp collected in the rainy season between May and June 2008. In L. setiferus, ciliates of the subclass Apostomatia (Ascophrys sp.) were evident in gills, and third-stage larvae of the nematode Physocephalus sexalatus were evident in the stomach. Cestodes of the genus Prochristianella were evident in the hepatopancreas, while some gregarines of the genus Nematopsis, as well as unidentified larval cestodes, were observed in the intestine. Histology identified Ascophrys sp. in association with gill necrosis and tissue melanization. Slight inflammation was observed in intestinal epithelium near cestode larvae. In M. acanthurus, epibionts of the protozoans Epistylis sp., Acineta sp. and Lagenophrys sp. were observed under uropods, periopods and pleopods. An unidentified ciliate of the Apostomatia was also found in the gills, and Nematopsis was identified in the intestine. No histopathology was observed in association with these parasites. Moreover, neither WSSV nor IHHNV were detected by the polymerase chain reaction (PCR) in any of the L. setiferus or M. acanthurus analysed.

Assuntos

RESUMO

Previously undescribed infective larvae of the cystidicolid nematode Pseudoproleptus sp. (probably conspecific with the nematode originally described as Heliconema izecksohni Fabio, 1982, a parasite of freshwater fish in Brazil), were found encapsulated in the hemocel of the Amazon river prawn Macrobrachium amazonicum (Heller) (Decapoda: Palaemonidae) from the natural canals on the Mexiana Island (Amazon River Delta), Pardá State, Brazil. The prevalence in prawns (body length 48-110 mm) examined in January and March 2008 (n = 44) was 32%, with an intensity of 1-6 (mean 2) larvae per crustacean. The nematode larvae (body length 19.7-25.7 mm), characterized by the cephalic end provided with a helmet-like cuticular structure having a thickened free posterior margin, are described based on light and scanning electron microscopy. Apparently prawns play a role as intermediate hosts for this nematode species. This is the first record of a larval representative of Cystidicolidae in South America and the first record of a species of Pseudoproleptus Khera, 1955, in the Neotropics. Heliconema izecksohni is transferred to Pseudoproleptus as Pseudoproleptus izecksohni (Fabio, 1982) n. comb.

Assuntos

RESUMO

Two leech species were found parasitizing the shrimp Cryphiops caementarius from Limarí river, Chile. These ectoparasites can act as population regulators or development inhibitors in their host; however the biological characteristics of this host-parasite interaction are unknown. We analyze the inter-specific differences of the parasitism and its relation with host size and sex using quantitative descriptors. Abundance, prevalence, intensity and range were estimated with respect to host size and sex. The leeches belong to two species of Glossiphonidae: Helobdella triserialis and H. duplicata. Forty-seven percent of the hosts were parasitized by one or both leech species. H. triserialis was found only in the pleopod of the hosts with the highest prevalence values (42%), intensity (2.9) and range (1-11). H. duplicata was found only in the branchial filaments with 7 % prevalence, an intensity of 1.7 and a range of 1-4. The host's total length and sex can explain the variation in leech intensity and infection prevalence. However, when only the host's sex is considered, prevalence only increased with size in female hosts. Morphological characteristics of the females could explain the greater H. triserialis intensity in the base of the pleopod and would be related to a greater abdomen development.

Assuntos

RESUMO

Two leech species were found parasitizing the shrimp Cryphiops caementarius from Limarí river, Chile. These ectoparasites can act as population regulators or development inhibitors in their host; however the biological characteristics of this host-parasite interaction are unknown. We analyze the inter-specific differences of the parasitism and its relation with host size and sex using quantitative descriptors. Abundance, prevalence, intensity and range were estimated with respect to host size and sex. The leeches belong to two species of Glossiphonidae: Helobdella triserialis and H. duplicata. Forty-seven percent of the hosts were parasitized by one or both leech species. H. triserialis was found only in the pleopod of the hosts with the highest prevalence values (42%), intensity (2.9) and range (1-11). H. duplicata was found only in the branchial filaments with 7 % prevalence, an intensity of 1.7 and a range of 1-4. The host's total length and sex can explain the variation in leech intensity and infection prevalence. However, when only the host's sex is considered, prevalence only increased with size in female hosts. Morphological characteristics of the females could explain the greater H. triserialis intensity in the base of the pleopod and would be related to a greater abdomen development.

Assuntos