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Background: Gastrointestinal parasites may determine diarrhea, dysentery or even death in captive mammals. These animals tend to be more susceptible to parasitic infections due to confinement and stress. Purpose To increase the information about these etiological agents in captive animals in Brazil, the gastrointestinal parasites of the captive mammals of the Rio de Janeiro Zoo were investigated., Methods: From 2016 to 2018, 180 fecal samples were collected from animals housed in the Rio de Janeiro Zoo: 63 from animals of the order Primates, 26 of Carnivora, 78 of Artiodactyla, 9 of Perissodactyla and 4 of the order Rheiformes. The feces were processed by direct examination and by the techniques of Faust et al., Sheather, Ritchie, Lutz, and smears were stained with safranin. Immunoenzymatic assays were also performed to investigate antigens of Giardia duodenalis, Cryptosporidium spp., Entamoeba histolytica/Entamoeba dispar., Results: Parasite positivity was identified in 68.3% of the fecal samples, with a parasite positivity rate of 68.2% among primates, 65.3% among carnivores, 69.2% among artiodactyls, 33.3% among perissodactyls, and 100% among rheiformes. The most frequently detected parasite was Entamoeba histolytica/E. dispar antigens, which showed a statistically significant positivity rate (33.3%; p = 0.000), particularly in the feces of carnivores (30.7%) and artiodactyls (53.8%). A statistically significant positivity rate of Balantioides coli (11.1%; p = 0.001) was also detected in feces from nonhuman primates, tapirs, collared peccaries and rheas. The positivity of Cryptosporidium sp. antigens in feces of the orders Carnivora, Artiodactyla and Primates was also statistically significant (7.2%, p = 0.010). Oocysts compatible with Cryptosporidium spp. were detected in 6.3% from primates. The helminths most frequently detected were thin-shelled eggs of nematodes (17.7%, p = 0.000), nematode larvae (15.5%, p = 0.000) and Trichuris trichiura eggs (6.1%, p = 0.018)., Conclusion: The positivity rate for gastrointestinal parasites demonstrates the need for a sanitation management program to be implemented in the zoo, including routine diagnostic parasitology tests followed by specific treatment for each parasitosis.

Purpose: This study aimed to compare the performance of four different microscopic coproparasitological techniques in relation to egg recovering and the frequency of alterations in the eggs observed through each technique., Methods: A total of 213 fecal samples from free-living carnivorous mammals were collected between 2017 and 2018 in Itatiaia National Park, RJ, Brazil. Faust and modified Sheather floatation techniques as well as Lutz and modified Ritchie sedimentation techniques were applied., Results: The total positivity rate for Spirometra spp. eggs was 24.4%, and these were detected mainly through Lutz and modified Ritchie sedimentation techniques, with substantial agreement (kappa = 0.73; p = 0.00 < 0.05; McNemar p value = 1.0; Fisher's exact test p = 0.616). Faust and modified Sheather flotation techniques did not present good egg recovery, with frequencies of 6.6% and 7.5%, respectively. Eggs with morphological alterations were mostly observed through Faust (17.3%) and modified Sheather (13.5%). Both flotation techniques presented statistically significant frequencies of deformed eggs, in comparison with the sedimentation techniques (p = 0.00). Low frequencies of deformed eggs were observed when the samples were analyzed through modified Ritchie and Lutz sedimentation techniques., Conclusions: From these results, sedimentation techniques such as modified Ritchie and Lutz methods were more efficient for diagnosing the eggs of this helminth in fecal material from free-living carnivores and should always be used when analyzing fecal samples from hosts of different species.

Balantioides coli is a ciliated protozoon that inhabits the intestine of pigs, non-human primates and humans. Light microscopy studies have described over 50 species of the genus Balantioides but their validity is in doubt. Due to the limited information about this genus, this study is aimed to identify morphological characteristics of Balantioides coli isolated using fluorescence microscopy and both scanning (SEM) and transmission electron microscopy (TEM). Trophozoites isolated from the feces of pig and macaque were washed and subjected to centrifugation. These cells were fixed with paraformaldehyde for immunofluorescence. Other aliquots of these trophozoites were fixed with glutaraldehyde, post fixed with osmium tetroxide and processed for SEM and TEM. Immunofluorescence studies revealed microtubules with a longitudinal distribution to the main axis of the parasite and in the constitution of cilia. SEM demonstrated a high concentration of cilia covering the oral apparatus and a poor presence of such structures in cytopyge. TEM revealed in the plasma membrane, several associated structures were observed to delineate the cellular cortex and mucocysts. The cytoskeleton of the oral region was observed in detail and had an organization pattern consisting of microtubules, which formed files and nematodesmal networks. Organelles such as hydrogenosomes like and peroxisomes were observed close to the cortex. Macronuclei were observed, but structures that were consistent with micronuclei were not identified. Ultrastructural morphological analysis of isolates confirms its similarity to Balantioides coli. In this study were identified structures that had not yet been described, such as hydrogenosomes like and cytoskeletal structures.