Hemoparasite Analysis and Hematological Parameters of Four Freshwater Turtle Species (Testudines: Podocnemididae) from the Brazilian Amazon.

METHODS: Sampling was performed at three sites in the Tapajós River mouth, Pará State, Brazil, and an aliquot of blood was collected from each turtle by post-occipital dorsal vein puncture. The aliquots were used for the determination of hematological parameters and for the study of hemoparasites in the blood samples. RESULTS: A total of 37 turtles were sampled: 21 Podocnemis expansa, three P. sextuberculata, nine P. unifilis, and four P. erythrocephala. Parasitological analyses showed inclusions in erythrocytes compatible with Haemogregarina sp., representing an overall prevalence of parasitized animals of 64.8% with an average of 94,789 parasites/ml of blood. In this study, the evolutionary forms of Haemogregarina spp. from trophozoites, pre-meronts, meronts, and mature and immature gamonts were observed in three species of freshwater turtle species, and one morphotype of the parasite with high similarity to Haemogregarina podocnemis has been observed. CONCLUSION: Despite recent research on freshwater turtles, this study provides new information on the intensity of blood parasite infection and hematological parameters of free-living animals, highlighting the need for studies on infected and uninfected animals from the same population.

Blood parasites (Kinetoplastida: Trypanosomatidae) infecting birds in the Brazilian Amazon / Parásitos sanguíneos (Kinetoplastida: Trypanosomatidae) que infectan aves en la Amazonía brasileña

Abstract Introduction: Trypanosomes are hemoparasites that can be observed circulating in the peripheral blood of birds. Parasitological studies in birds in their natural environment are neglected, but are important for research relating to transmission, maintenance of the biological cycle, and abundance, among other parasitological aspects. Objective: To describe infections by Trypanosoma sp. in birds in the Brazilian Amazon, as well as the prevalence, morphological and morphometric characteristics of this hemoparasite. Methods: In the Tapajós National Forest, we captured a total of 125 birds, mostly from the order Passeriformes. We obtained blood samples from the ulnar vein using sterile insulin needles, and aliquots of blood using a microhematocrit capillary tube. We made blood smears in triplicate and stained with the Giemsa method. We viewd the morphotypes of the Trypanosoma sp. under the light microscope with objective lenses of 40 X and 100 X. To determine the morphometric characteristics of Trypanosomatidae, we used the Zen Blue Edition 2 software package. Results: We observed the presence of hemoparasites in the trypomastigote form in specimens of Thamnophilidae, Dendrocolaptidae and Conopophagidae, with low prevalence. Only one morphotype of Trypanosoma sp. was detected and measurement. Conclusions: We report the infection by Trypanosoma sp. in species of ecological importance, such as Phlegopsis nigromaculata, endangered in Brazil. The morphology and morphometry of the morphotype found could contribute to more detailed descriptions of these hemoparasites.

Resumen Introducción: Los tripanosomas son hemoparásitos que pueden observarse circulando en la sangre periférica de las aves. Los estudios parasitológicos en aves en el medio natural son escasos, pero son importantes para la investigación relacionada con la transmisión, el mantenimiento del ciclo biológico y la abundancia, entre otros aspectos parasitológicos. Objetivo: Describir infecciones por Trypanosoma sp. en aves de la Amazonia brasileña, así como la prevalencia, características morfológicas y morfométricas de este hemoparásito. Métodos: En la Floresta Nacional de Tapajós, capturamos un total de 125 aves, la mayoría del orden Passeriformes. Obtuvimos muestras de sangre por punción de la vena cubital del ala con agujas estériles de insulina. Con un tubo capilar microhematocrito, obtuvimos alícuotas de sangre. Realizamos frotis de sangre por triplicado y teñimos con el método de Giemsa. Visualizamos los morfotipos de Trypanosoma sp. al microscopio óptico con lentes objetivos de 40 X y 100 X. Para determinar las características morfométricas de Trypanosomatidae, usamos el paquete informático Zen Blue Edition 2. Resultados: Observamos la presencia de hemoparásitos en la forma tripomastigote en ejemplares de la familia de aves Thamnophilidae, Dendrocolaptidae y Conopophagidae, con baja prevalencia. Solo detectamos un morfotipo de Trypanosoma sp. Conclusión: Reportamos la infección por Trypanosoma sp. en especies de importancia ecológica, como Phlegopsis nigromaculata en peligro de extinción en Brasil. La morfología y morfometría del morfotipo encontrado puede contribuir con descripciones más detalladas de estos hemoparásitos.

Rhinella major (Anura: Bufonidade): a new paratenic host of Centrorhynchus sp. (Palaeacanthocephala: Centrorhynchidae) in Brazilian Amazon.

Acanthocephalans are grouped in a single phylum, having a cosmopolitan distribution and subdivided into several genera. Although species of this parasite genus have birds and mammals as definitive hosts, they have been reported in amphibians and reptiles, and have been noted as paratenic hosts. In this study we report the record of Rhinella major as a new paratenic host for the Centrorhynchus sp. from an urban area of the Brazilian Amazon. In this study, for the morphometric measurements to take place, the parasitic specimens found were fixed and preserved in an alcoholic liquid medium and the identification of the parasites found were confirmed by specialized literature. The parasitological statistical parameters followed the proposed ecological concepts, calculating the parasite prevalence, intensity, average intensity and average abundance indices with confidence intervals. In the present study, two morphotypes of Acontochephala were found parasitizing R. major. In this study we report the record of R. major as a new paratenic host for the Centrorhynchus sp.

Metazoan parasites of Plagioscion squamosissimus (Osteichthyes: Sciaenidae) of two rivers from the eastern Amazon (Brazil).

Plagioscion squamosissimus, commonly known as "white hake" or "corvina", is among the most commercially important fish in the Amazon and host to a great diversity of endoparasites. The aim of the present study was to compare the communities and infracommunities of metazoan parasites that infect P. squamosissimus in two rivers from the eastern Brazilian Amazon. A total of 75 specimens of P. squamosissimus were collected from Lago Grande do Curuái and the mouth of the Tapajós River. Morphological analysis revealed the presence of 16 parasite species, three myxozoans (Myxobolus sp., Ceratomyxa sp., Henneguya sp.), two trematodes (Austrodiplostomum compactum, Digenea gen. sp. (metacercariae), two monogeneans (Diplectanum sp., Euryhaliotrema sp.), three nematodes (Procamallanus (S.) sp., Anisakis sp., Pseudoproleptus sp. (larva), two acanthocephalans (Rhadinorhynchus plagioscionis and Neoechinorhynchus sp.), one Cestoda Ptychobothriidae gen. sp. and three crustaceans (Therodamas sp., Ergasilus sp., Dolops sp.). Six new records of parasites of P. squamosissimus were made, of which three were myxozoan species, one nematode species and two crustacean species. There were differences in the component communities of parasites of both rivers studied and these were discussed.

Host-parasite interaction between trematode, Clinostomum marginatum (Clinostomidae) and armoured catfish, Pterygoplichthys pardalis (Loricariidae) from Brazilian Amazon.

Clinostomid trematodes are only widely studied due to the ability to infect their metacercariae, which can affect amphibians, fish, snakes and occasionally mammals, with occasional records in humans. The Loricariids constitute the most diverse family of neotropical fish, with more than 800 registered species. They present a large heterogeneity of colors and body forms that reflect its high degree of ecological specialization and importance on economic aspects such as ornamentation and food. In spite of these factors, studies involving the diversity of parasitic fauna that affect in these fish is still scarce. In this aspect, our study presents the first record of occurrence of the parasite Clinostomum marginatum in association with the Loricariid Pterygoplichthys pardalis in the Amazon region of Brazil. In September 2018, in the river mouth of Tapajós river, tributary of Amazon river, 32 specimens of P. pardalis and six specimens of Aphanotorulus emarginatus were captured. The parasitological studies revealed the occurrence of metacercariae of C. marginatum in association with P. pardalis, representing a prevalence of 12.5% with a mean abundance of 0.18 and a medium intensity of infection of 1.5. No C. marginatum parasitism was observed in A. emarginatus.

Parasitism by Clinostomum marginatum (Clinostomidae) in neotropical electric fish (Gymnotiformes) in the Brazilian Amazon

Gymnotiformes are currently recognized as electric fish, the vast majority of which emit low power electrical discharges. Clinostomum trematodes have been the subject of numerous investigations in several host species due to the ability of metacercariae of this genus to infect the muscles, fins and internal organs of fish. The present study aimed to record, for the first time, the occurrence of parasitism by Clinostomum marginatum in Gymnotiformes from the natural environments of two tributaries of the Amazon River in the Brazilian Amazon. Two specimens of Gymnotus coropinae, ten specimens of Brachyhypopomus brevirostris, two specimens of Gymnorhamphycthys petiti and one specimen of Microsternarchus bilineatus were captured. Infection with C. marginatum was identified in the form of 12 encysted metacercariae in the epidermis, with a prevalence of 0.1%, a mean infection intensity of 12/fish and an average abundance of 1.2. This is the first record of parasitism by the C. marginatum in South American Gymnotiformes of the B. brevirostris species.