This study investigated the in vivo and in vitro antiparasitic effects of the essential oil of Lippia alba and the bloodrelated and histopathological alterations that it causes in Colossoma macropomum. In the in vitro trial, the anthelminthic effects of 160, 320, 640, 1280 and 2560 mg/L of the essential oil were tested against monogenoideans (Anacanthorus spathulatus, Notozothecium janauachensis and Mymarothecium boegeri) of the gills of this fish, which are its natural parasites. The concentrations of 1280 mg/L and 2560 mg/L showed 100% efficacy after 20 min of exposure to the essential oil, while at lower concentrations this efficacy against the gill monogenoideans only occurred after 2-3 h of in vitro exposure. However, in the controls, mortality of all of these monogenoideans only occurred after 9 h. A total of 240 fry were distributed into four treatments (20 fish per repetition) and three repetitions were used in the in vivo trial for baths with 100 and 150 mg/L of the essential oil of L. alba, for 30 min. The efficacy in this trial against Ichthyophthirius multifiliis in fish exposed to 100 and 150 mg/L of the essential oil was 40.7% and 50.3%, respectively. However, for monogenoideans, there was efficacy of 14.0% only in the fish exposed to 100 mg/L of the essential oil used. Moreover, the fish exposed to these concentrations of the essential oil presented increased plasma glucose levels, thus denoting signs of stress. Severe lesions such as hyperplasia, fusion of the lamellar epithelium, capillary dilatation, epithelial detachment, lamellar aneurysm, epithelial rupture with hemorrhage, congestion, edema, necrosis, mucous cell proliferation, chloride cells and lamellar hypertrophy were observed in the gills of the fish exposed to 100 and 150 mg/L of the essential oil of L. alba. Alterations to total protein levels, hemoglobin, hematocrit, red blood cell number, thrombocytes number, white blood cell number, lymphocytes, eosinophils and blood neutrophil number was also observed in these fish. The essential oil of L. alba showed great potential for antiparasitic treatment, given that it had high in vitro efficacy against monogenoideans and in vivo efficacy against the protozoon I. multifiliis. Because of the low concentrations of the essential oil (100 and 150 mg/L) that were tolerated by the fish and thus could be used in the therapeutic baths, the efficacy against monogenoideans was low. This indicates that there is a need for additional strategies for using this essential oil in antiparasitic treatments, since the concentrations that eliminate these ectoparasites are toxic for the hosts. Lastly, this was the first study on the antiparasitic activity of L. alba. Statement of Relevance The manuscript entitled "Antiparasitic activity of the essential oil of Lippia alba on ectoparasites of Colossoma macropomum (tambaqui) and its physiological and histopathological effects", represents original article on use of the essential oil of Lippia alba on ectoparasites of tambaqui, an important finfish of Amazon regio...

Parasite infracommunities were studied in 202 specimens of Astronotus ocellatus collected from a freshwater lake in the State of Amapá, northern Brazil. Relationships between some host attributes (i.e., ontogeny, sex, and body size) and parasite infections were analyzed, but the primary focus was the seasonal variation in the parasite fauna. In total, 6,308,912 parasites belonging to 11 different taxa were found. Protozoa were the most abundant and dominant taxa, but monogeneans, trematode metacercariae, and nematode larvae were also prevalent and abundant. Fish ontogeny had a weak influence on parasite infection rates; juveniles were more parasitized by Dolops nana and Posthodiplostomum sp. The abundances of all parasite species were weakly correlated with host body size (low r(2) values), except D. nana, Contracaecum sp., and Posthodiplostomum sp., which exhibited no correlation between abundance and host body size. Prevalence and abundance were different between flood and drainage seasons for all parasite species, except for D. nana and the 2 metacercarial species. Astronotus ocellatus may represent a link in food-web transmissions for parasites because it is used both as definitive and intermediate host. The parasite fauna of A. ocellatus was composed primarily of ectoparasites, and this could be considered typical of fishes that inhabit lentic waters. Seasonality was a strong determinant in the parasite community structure.

O objetivo principal deste trabalho foi estudar a parasitofauna e a relação hospedeiro- parasito em tambaqui Colossoma macropomum cultivados em tanques-rede no Rio Matapi, município de Santana, estado do Amapá, região da Amazônia oriental, Brasil. Foram examinados 60 tambaquis, dos quais 96,7% estavam parasitados por protozoários Ichthyophthirius multifiliis (Ciliophora) e Piscinoodinium pillulare (Dinoflagellida), monogenoideas Mymarotheciun boegeri e Anacanthorus spathulatus (Dactylogyridae) e sanguessugas Glossiiphonidae gen. sp. (Hirudinea). Os maiores níveis de parasitismo foram causados por protozoários I. multifiliis e P. pillulare e os menores por sanguessugas Glossiiphonidae gen. sp. Porém, os índices de infestação não tiveram efeitos na saúde dos peixes hospedeiros, uma vez que o fator de condição relativo (Kn) não foi estatisticamente (p<0,05) correlacionado com a intensidade desses parasitos. Este foi o primeiro relato da ocorrência de I. multifiliis e P. pillulare em C. macropomum cultivados em tanques-rede na Amazônia brasileira.

The present study investigated the effects of seasonal variation in parasites infracommunities of Hoplerythrinus unitaeniatus and Hoplias malabaricus from a tributary of Amazon River. For H. unitaeniatus and H. malabaricus, 11 parasite species were similar, and greatest parasite richness occurred during the rainy season. Ichthyophthirius multifiliis was the dominant parasite species for both hosts. In H. unitaeniatus, infection by Whittingtonocotyle caetei, Whittingtonocotyle jeju, Urocleidoides sp. and Anacanthorus sp. was higher during rainy season. Contracaecum sp., Procamallanus (Spirocamallanus) inopinatus, Nomimoscolex matogrossensis and Gorytocephalus spectabilis showed no seasonal pattern. For H. unitaeniatus, P. pillulare, Clinostomum marginatum and Argulus pestifer occurred only during dry season, while Trichodina sp., Dolops geayi, undetermined metacercariae and Posthodiplostomum sp. occurred only during the rainy season. In H. malabaricus, the prevalence of Urocleidoides eremitus was similar during the two seasons, but abundance was higher during the rainy season. Tetrahymena sp., C. marginatum, Dendrorchis neivai, undetermined metacercariae, Posthodiplostomum sp., Genarchella genarchella, Cystidicoloides sp., G. spectabilis, D. geayi, A. pestifer and Glossiphonidae gen. sp. occurred only during the dry season. However, Contracaecum sp. and P. (S.) inopinatus occurred during both seasons, but the prevalence of P. (S.) inopinatus was higher during the rainy season. Seasonal variation in this infection levels was due to the host's feeding behavior and habits and the availability of infectious forms of parasites with heteroxenic life cycles. The non-seasonal fluctuation detected are likely a result of the parasites biology, highly variable nature of this tributary of Amazon River and low abundance of parasites.

This work is the first study on parasitic fauna of Curimata cyprinoides Linnaeus, 1766 (Curimatidae) and the host-parasite relationship. The total of 154,740 parasites such as Ichthyophthirius multifiliis (Ciliophora), trophozoite of Spironucleus sp. (Hexamitidae), Urocleidoides sp. (Monogenoidea), Digenea gen. sp. and Polymorphus sp. (Polymorphidae) were collected. The component community showed low diversity (HB = 0.004 ± 0.020) and parasite species richness (1.4 ± 0.6). However, I. multifiliis and Urocleidoides sp. were prevalent and with higher intensity on the host population and also aggregated the distribution pattern. The occurrence of these ectoparasites in C. cyprinoides may be a consequence of its alimentary diet. Positive correlation between the abundance and size of I. multifiliis and the relative condition factor of the host were observed and discussed. These data represent increased knowledge of the biology of these parasites. Furthermore, this study expanded the geographic distribution of some parasite species for this new host from Brazil. Parasitos em Curimata cyprinoides (Pisces, Curimatidae) da Amazônia oriental, Brasil RESUMO. Este trabalho providenciou o primeiro estudo sobre a fauna parasitaria de Curimata cyprinoides Linnaeus, 1766 (Curimatidae) e relação hospedeiro-parasito. Foram coletados 154.740 parasitos, tais como Ichthyophthirius multifiliis (Ciliophora); trofozoíto de Spironucleus sp. (Hexamitidae); Urocleidoides sp. (Monogenoidea); Digenea gen. sp. e Polymorphus sp. (Polymorphidae). A comunidade componente apresentou baixa diversidade (HB = 0,004 ± 0,020) e riqueza de parasitos (1,4 ± 0,6). Ichthyophthirius multifiliis e Urocleidoides sp. apresentaram a maior prevalência e intensidade na população de hospedeiro e tiveram padrão de distribuição agregado. Em C. cyprinoides, a ocorrência desses ectoparasitos pode ser uma consequência da ampla variedade de sua dieta alimentar. Correlação positiva da abundância de I. multifiliis como o tamanho e fator de condição relativo dos hospedeiros foi observada e discutida. Estes dados representam um aumento do conhecimento sobre a biologia desses parasitos. Além disso, este estudo ampliou a distribuição geográfica de algumas espécies de parasitos para este novo hospedeiro no Brasil.Palavras-chave: ecologia, brânquias, peixe de água doce, Monogenoidea, protozoários.

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Helminthes and protozoan of farmed pirarucu (Arapaima gigas) in easternAmazon and host-parasite relationship [ ABSTRACTThe parasitofauna in the giant Amazon basin, pirarucu (Arapaima gigas Schinz, 1822) cultured in fish farms from the state of Amapá, in eastern Amazonia (Brazil) was investigated. Of the 100 examined fish, 90.0% were parasitized by Ichthyophthirius multifiliis (Ciliophora), Dawestrema cycloancistrium, Dawestrema cycloancistrioides (Monogenoidea) and Polyacanthorhynchus macrorhynchus (Acanthocephala), which had an aggregated distribution pattern. The highest infection rates were caused by I. multifiliis and the lowest by P. macrorhynchus. Infection rates were different for each fish farm, due to different water quality and management characteristics. A negative correlation was found between the intensity of monogenoideans D. cycloancistrium and D. cycloancistrioides and the relative condition factor (Kn), but the welfare of fish was not affected by parasitism. The number of I. multifiliis was positively correlated with the weight and total length of hosts, while the intensity of monogenoideans was negatively correlated with body weight and total length. This study is the first to record the occurrence of P. macrorhynchus in A. gigas farmed in Amazon.Keywords: Amazonia, fish farm, freshwater fish, parasites, sanity RESUMO Investigou-se a parasitofauna no gigante da bacia amazônica, pirarucu (Arapaima gigas

RESUMOOs estudos sobre os parasitos e doenças parasitárias são de grande interesse para a piscicultura, uma vez que podem afetar o crescimento dos peixes. O objetivo deste estudo foi investigar a fauna parasitária e relação parasito-hospedeiro em Colossoma macropomum x Piaractus brachypomus (tambatinga) de 10 pisciculturas do estado do Amapá, Amazônia. Parasitism in tambatinga (Colossoma macropomum x Piaractus brachypomus, Characidae) farmed in the Amazon, Brazil ABSTRACTThe studies on parasites and parasitic diseases are of great interest to fish farms, because both can affect the performance of the fish. The aim of study was to investigate the parasitic fauna and parasite-host relationship in Colossoma macropomum x Piaractus brachypomus (tambatinga) of 10 fish farms from the Amapá State, in the Amazon. Of the 503 fish examined 63.1% were parasitized, and a total of 49,299,189 parasites were collected, including Ichthyophthirius multifiliis, Piscinoodinium pillulare, Trichodina sp., Tetrahymena sp., Anacanthorus spathulatus, Linguadactyloides brinkmanni, Mymarothecium boegeri, Notozothecium janauachensis, Procamallanus (Spirocamallanus) inopinatus, Neoechinorhynchus buttnerae and Perulernaea gamitanae. Ichthyophthirius multifiliis was the dominant species, followed by P. pillulare and monogenoideans; these two parasites and P. gamitanae showed an aggregated dispersion pattern. We found a positive correlation between host length and the overall parasitic prevalence, as well as between fish size and the abundance of I. multiliis, P. pillulare, monogenoideans and P. gamitanae, but infection levels did not affect the relative condition factor of hosts. Management, low environmental quality and poor sanitary conditions of the fish farms favored the occurrence of ectoparasites, but the presence of endoparasites was due to supplying the ponds directly with water of natural water bodies. This is first report of I. multiliis, P. pillulare, Trichodina sp., Tetrahymena sp., A. spathulatus, N. janauachensis, N. buttnerae and P. (S.) inopinatus for tambatinga in Brazil.