RESUMO -Os peixes de uma estação de cultivo de tambaquis pararam de se alimentar e começaram a morrer. Um total de 72 peixes foi examinado. Todos os peixes estavam com uma alta infestação intestinal por acantocéfalos. A espécie parasita foi identificada como Neoechinorhynchus buttnerae Golvan, 1956. A prevalência foi de 100%, a intensidade por hospedeiro variou de 30 a 406 e a intensidade média e densidade relativa (abundância) foram de 125, 26. Ocorreu oclusão total do trato intestinal nas altas infestações.Palavras-chave: Acanthocephala; parasitas de peixes; tambaqui; mortalidade de peixes; aquacultura. ABSTRACT -The fishes Colossoma macropomum (Cuvier, 1818) from a farm fish stopped to eat and begun to die. Seventy-two fishes caught were examined. All fishes had a high intesti nal infestation for Acanthocephala. The species was Neoechinorhynchus buttnerae Golvan, 1956. The prevalence was 100%, intensity range 30-406 and mean intensity and relative density (abun dance) were 125,26. In the high infestations occurred the total occlusion of the gut lumen. Massive Infestation by

Foram examinados brânquias, fossas nasais e intestinos de tambaquis (Colossoma macropomum) capturados em duas localidades na Amazônia, próximas aos municípios de Tefé/Coari, no médio rio Solimões, Estado do Amazonas e de Santarém no baixo rio Amazonas, Estado do Pará. Nove espécies de parasitas foram encontradas: três da classe Monogenoidea; Anacanthorus spathulatus, Linguadactyloides brinkmanni e Notozothecium sp.; uma de Trematoda da família Paramphistomidae; uma do filo Acanthocephala, Neoechinorhynchus buttnerae, duas do filo Nematoda, Spirocamallanus sp. e Procamallanus sp. e duas da subclasse Copepoda, Gamidactylus jaraquensis e Perulernaea gamitanae. Foram registradas pela primeira vez parasitando o tambaqui, o monogenético Notozothecium sp., espécimens imaturos da família Paramphistomidae, larvas do nematóide Procamallanus sp. e o copépodo Gamidactylus jaraquensis. Os paranfistomídeos e Procamallanus sp. foram encontrados apenas nos hospedeiros da região de Tefé/Coari. Foi observada pouca variabilidade na composição da parasitofauna do tambaqui, entre os dois locais estudados. As espécies Anacanthorus spathulatus, Notozothecium sp., Neoechinorhynchus buttnerae e Perulernaea gamitanae, apresentaram bom potencial como indicadores biológicos para o tambaqui.

Resumo A especificidade parasitária, áreas de fixação, hospedeiros naturais, índices de infestação e variação sazonal de Dolops striata e Dolops carvalhoi foram estudados durante o período de março de 1979 a março de 1980, na área do Janauacá, um lago de várzea da Amazônia Central. A sazonalidade revelou um estreito relacionamento com a variação do nível da água, sendo que os picos máximos de infestação de D. striata e D. carvalhoi ocorreram na estação de rio cheio (abril, maio) e os picos mínimos na estação de seca (setembro, outubro). O D. carvalhoi apresentou uma baixa especificidade parasitária, foi encontrado parasitando sete espécies de peixes incluídas em quatro famílias, três da Pimelodidae, duas da Serrasalmidae, uma da Characidae e uma da Clupeidae. O D. striata apresentou um alto grau de especificidade parasitária ocorrendo em três espécies de peixes incluídas em uma única família, a Anostomidae. Ambas espécies foram encontradas parasitando a superfície externa do corpo de seus hospedeiros.

of the metazoan fauna of Pygocentrus nattereri (Kner, 1858) in Piranha Lake, (Amazonas, Brazil), and evaluation of its potential as an indicator of environmental health. Biota Neotrop. 11(1): http://www.biotaneotropica.org.br/v11n1/en/ abstract?article+bn03111012011. Abstract:The metazoan parasitic fauna of Pygocentrus nattereri collected in different phases of hydrologic cycle of Piranha lake was studied during the year of 2007. The study area is located in gas pipeline Coari-Manaus construction zone, near the municipality of Manacapuru-Am. The relationship between condition factor and parasite occurrence and the viability of use the parasitic fauna as an environmental bio-indicator were verified. The following Monogenoidea were collected: Amphithecium microphalum, Amphitecium brachycirrum, Amphitecium calycinum, Amphithecium catalaoensis, Amphithecium junki, Pithanothecium amazonensis e Rhinoxenus piranhus, as well as the nematode Procamallanus inopinatus, the copepod Miracetyma sp. and the isopod Anphira branchialis. There was not significant correlation between the parasite occurrence and the condition factor. There were significant variances in the parasitic index according to the different periods of hydrologic cycle and P. nattereri has achieved the conditions described in the literature to be select a fish-host and his parasite fauna as biomonitor.

Larvae of Hysterothylacium use various invertebrates as intermediate hosts. Definite hosts include fish, birds, reptiles or marine mammals. This study describes the occurrence of Hysterothylacium (Nematoda, Anisakidae) larvae parasitizing the pericardic cavity of Diplodon suavidicus (Unioniformes, Hyriidae) specimens collected in the Amazon basin, Brazil. This is the first record of this nematode parasitizing freshwater bivalves in South America. The high prevalence, medium intensity and medium abundance suggest that D. suavidicus acts as intermediate host for Hysterothylacium species in that environment.

A new myxosporean species is described from the fish Semaprochilodus insignis captured from the Amazon River, near Manaus. Myxobolus insignis sp. n. was located in the gills of the host forming plasmodia inside the secondary gill lamellae. The spores had a thick wall (1.5-2 µm) all around their body, and the valves were symmetrical and smooth. The spores were a little longer than wide, with rounded extremities, in frontal view, µm long by 11.3 (11-12) µm wide and 7.8 (7-8) provided a synopsis of the species giving the full characterisation of 744 nominal species, including nearly all the species described so far in fish and amphibians. It is surprising that from such a high number of species only 21 were described for South America -2 from Argentina, 1 from Guiana, and 18 from Brazil. This is surprising because the fish diversity in Brazilian waters is very high, comprising about 8000 species representing nearly 24% of all the known fish species (Cellere et al. 2002). It is likely that the small number of Myxobolus species known so far for this region (as well as of other Myxosporea species) does not mean a scarcity of parasites in this part of the world, but a lack of research on Myxosporea (Cellere et al. 2002).In this paper we describe Myxobolus insignis sp. n. (Myxozoa, Myxosporea, Myxobolidae) from the "jaraqui", Semaprochilodus insignis Jardine & Schomburgk, 1841 (Osteichthyes, Prochilodontidae), a freshwater fish from the Amazon River, Brazil. This fish species, jointly with S. taeniurus, is most important for a large part of the Central Amazon human population once they represent its main food resource. MATERIALS AND METHODSThree specimens of S. insignis (total length: 22.3-24.5 cm) were net-fished from the Amazon river, at Manaus, and transported to the laboratory. The specimens were thoroughly dissected under a compound microscope and all the organs were inspected for the presence of parasites. Measurements were made from fresh spores (30 specimens), and spores were observed under Nomarski differential interference-contrast. For detecting the presence of an iodinophilous vacuole fresh spores were treated with Lugol's iodine solution. Spores were also stained with India ink for revealing any mucous envelope (Lom & Vávra 1961). RESULTSTwo specimens of S. insignis exhibited the gills infected by Myxobolus. The parasites formed whitish, rounded or slightly irregular plasmodia (about 0.02-0.08 mm in diameter) located intra-lamellarly within the secondary gill lamellae. Most of the plasmodia were located at the base of the lamellae, but could be present also more or less far from the base.The spores (Figs 1-3) had a valvular wall 1.5-2 µm thick all around their body, and the valves were symmetrical and smooth. The spores were a little longer than wide, with rounded extremities, in frontal view, and oval in lateral view. They were 14.5 (14-15) µm long by 11.3 (11-12) µm wide and 7.8 (7-8) µm thick. Some spores showed the presence of a triangular thickening of the internal face of the wall near the posterior...

RESUMO -Uma nova espécie de Branchiura é descrita para o Brasil. Os espécimens foram coletados parasitando peixes da Amazônia brasileira. A nova espécie é caracterizada pela: coloração e desenhos da superfície dorsal da carapaça, tórax e abdômen; presença de espinhos em toda a margem externa da superfície ventral do abdômen (pléon); ornamentações das antenas, antênulas, maxilas, pernas, superfície ventral do corpo; forma e pigmentação das estruturas copulatórias acessórias do macho.

ResumoOs ciclídeos, peixes economicamente importantes na região, foram coletados no médio rio Negro (Cichla orinocensis, C. monoculus e C. temensis) e na iIlha da Marchantaria (C. monoculus), no Amazonas e em três açudes do Piauí (C. kelberi). Para verificar a ocorrência de parasitas as brânquias, narinas e intestino foram removidos e observados em microscópio esteroscópio, a boca a olho nu. Os parasitas encontrados foram retirados e armazenados em álcool 70% para posterior identificação. Dos 96 espécimes analisados provenientes do rio Negro 51 (52%) estavam parasitadas; dos 34 da ilha da Marchantaria 16 (47%) e dos 50 dos açudes do Piauí, apenas dois (4%). Nos peixes coletados no Amazonas, as brânquias estavam parasitadas por Ergailus coatiarus, Argulus amazonicus, Acusicola tucunarense e a boca por Braga cichlae, enquanto que os peixes do Piauí não apresentaram parasitas branquiais, mas registrou-se a ocorrência do nematóide Procamallanus (Spirocamallanus) inopinatus, parasita intestinal.Palavras-chave: Cichla spp., Amazonas, Piauí, parasitas. AbstractThe cichlids, economically important fish specie in the region, were collected along the Negro River (Cichla orinocensis, C. monoculus e C. temensis) and in the Marchantaria Island (C. monoculus) Amazon State and in three reservoirs localized in the Piauí State. In order to verify the occurrence of parasites, gills, nostrils and the intestine were removed and observed by stereomicroscope and the mouth by naked eyes. The observed parasites were isolated and conserved in 70% ethanol for posterior identification. From 96 specimens collected in Negro River, 51 specimens (52%) were parasitized. In the Marchantaria Island from 34 specimens collected, 16 (47%) showed the presence of parasites, and from 50 specimens collected in the reservoirs only 2 (4%) were parasitized. In fishes collected in the Amazon State, the grill was parasitized by Ergailus coatiarus, Argulus amazonicus, Acusicola tucunarense and the mouth by Braga cichlae, whereas the species collected in the Piauí State did not show the presence of parasites in the grill, but the occurrence of Procamallanus (Spirocamallanus) inopinatus an intestinal nematode parasite.