Detection of Anisakidae larvae parasitizing Plagioscion squamosissimus and Pellona castelnaeana in the State of Pará, Brazil / Detecção de larvas de Anisakidae parasitando Plagioscion squamosissimus e Pellona castelnaeana no Estado do Pará, Brasil

Five specimens of Plagioscion squamosissimus from Xingu River and ten specimens of Pellona castelnaeana from Mosqueiro Island, both in the State of Pará, Brazil, were examined to investigate the presence of anisakid nematodes, due to their zoonotic potential. Their parasitism indices and sites of infection were also determined. This is the first record of Anisakidae parasitizing Pellona castelnaeana. Four-hundred and eighty-four third-stage larvae (L3) of Anisakidae were found, of which 42 were found in P. squamosissimus and 442 in P. castelnaeana. The parasitism indices of the anisakid collected from the P. squamosissimus comprised prevalence (P) of 100%, mean infection intensity (MI) of 8.4, range of infection (RI) of 1- 13, mean abundance (MA) of 8.4, and infection site (IS) in the abdominal cavity. P. castelnaeana showed P = 100%, MI = 44.2, RI = 10-114, MA = 44.2, and IS = abdominal cavity, cecum and stomach. The life cycle of these nematodes can be completed in the Amazon basin, since the two hosts fish are part of the cetacean diet of the region, which participate as final hosts. These findings have an important consequence on epidemiology of anisakiasis, so attention should be extended to human protection against this public health risk.

Cinco espécimes de Plagioscion squamosissimus do rio Xingu e dez espécimes de Pellona castelnaeana da Ilha do Mosqueiro, ambos no Estado do Pará, Brasil, foram examinados para investigar a presença de nematodas Anisakidae, devido ao seu potencial zoonótico. Também foram determinados seus índices de parasitismo e sítios de infestação. Esse é o primeiro registro de Anisakidae parasitando Pellona castelnaeana. Foram encontradas 484 larvas de Anisakidae de terceiro estágio (L3), sendo 42 em P. squamosissimus e 442 em P. castelnaeana. Os índices parasitários de anisaquídeos coletados de P. squamosissimus compreenderam prevalência (P) de 100%, intensidade de infecção média (IM) de 8.4, amplitude de infecção (AI) de 1-13, abundância média (AM) de 8,4 e local de infecção (LI) na cavidade abdominal. P. castelnaeana apresentou P = 100%, IM = 44,2, AI = 10-114, AM = 44,2 e LI = cavidade abdominal, ceco e estômago. O ciclo de vida desses nematodas pode ser completo na bacia Amazônica, já que os dois hospedeiros fazem parte da dieta de cetáceos da região, que atuam como hospedeiros finais. Esses achados têm consequência importante na epidemiologia de anisaquíases, devendo haver mais atenção em relação à proteção humana contra esse problema de saúde pública.

Description of the karyotype of Geophagus cf. proximus (Perciformes, Cichlidae, Geophaginae) / Descrição do cariótipo de Geophagus cf. proximus (Perciformes, Cichlidae, Geophaginae)

This study described the karyotype of Geophagus cf. proximus. Specimens were collected in Água Preta Lake, Parque Ambiental de Belém, Pará State, Brazil. The karyotype were 2n = 48 chromosomes (FN = 60: 12M/SM+36ST/A) and no sexual chromosome differentiation. C-banding showed centromeric staining in all chromosomes. The first chromosome pair, besides centromeric coloration, presented a totally heterochromatic long arm. The nucleolus organizer regions (NORs) were studied by means of AgNO3. NORs were located at the short arm of the second chromosome pair.

Este estudo descreve o cariótipo de Geophagus cf. proximus. Espécimes foram coletados no lago Água Preta, Parque Ambiental de Belém, Estado do Pará, Brasil. O cariótipo obtido apresentou 2n = 48 cromossomos (NF = 60: 12M/SM+36ST/A), sem diferenciação de cromossomos sexuais. O bandeamento C mostrou marcações centroméricas em todos os cromossomos. O primeiro par cromossômico, além da coloração centromérica, apresentou o braço longo totalmente heterocromático. As regiões organizadoras do nucléolo (RONs) foram estudadas por meio da coloração de AgNO3. As RONs foram encontradas no braço curto do segundo par de cromossomos.

Studies of micronuclei and other nuclear abnormalities in red blood cells of Colossoma macropomum exposed to methylmercury

The frequencies of micronuclei (MN) and morphological nuclear abnormalities (NA) in erythrocytes in the peripheral blood of tambaqui (Colossoma macropomum), treated with 2 mg.L-1 methylmercury (MeHg), were analyzed. Two groups (nine specimens in each) were exposed to MeHg for different periods (group A - 24 h; group B - 120 h). A third group served as negative control (group C, untreated; n = 9). Although, when compared to the control group there were no significant differences in MN frequency in the treated groups, for NA, the differences between the frequencies of group B (treated for 120 h) and the control group were extremely significant (p < 0.02), thus demonstrating the potentially adverse effects of MeHg on C. macropomum erythrocytes after prolonged exposure.