Dolops intermedia Silva, 1978 (Crustacea: Argulidae) was described from Rio Grande do Sul state in the southernmost state of Brazil. Here, we report a new occurrence of this species from Maranhão state, 1 of the northernmost states of Brazil. The infection of new hosts Colossoma macropomum (Cuvier, 1816), Oreochromis niloticus (Linnaeus, 1758), Hoplias malabaricus (Bloch, 1794), Leporinus friderici (Bloch, 1794), and Pygocentrus nattereri (Kner, 1858) is reported for the first time. Additional morphological information is provided for some structures, and the ratios for body measurements are provided for the first time.

A new species of Bacciger Nicoll, 1914, is described from the digestive tract of the American gizzard shad, Dorosoma cepedianum (Lesueur), in some inland waterways of Mississippi, and in Mobile Bay, Alabama, U.S.A. This now represents the only nominal species in the genus from the northwest Atlantic Ocean or inland tributaries of eastern North America north of Mexico. Two potentially close relatives that range in the northwest Atlantic Ocean are Baccigeroides ovatus (Price, 1934) Cutmore, Bray and Cribb, 2018, and Pseudobacciger manteri Nahhas and Cable, 1964. The new species differs from Bo. ovatus mainly by having the genital pore opening immediately anteriad from the ventral sucker rather than far anteriad from it at the pharynx level, and from P. manteri mainly by having a distinct cirrus sac rather than having the terminal genitalia free in the parenchyma. The 3 genera are currently classified in the Faustulidae Poche, 1926. Although life cycles are unknown for the American species, evidence from life history of the related species Bacciger bacciger (Rudolphi, 1819) Nicoll, 1914, and Pseudobacciger harengulae (Yamaguti, 1938) Nahhas and Cable, 1964, combined with molecular phylogenetic evidence, indicate that the studied digeneans likely have a nonoculate trichocercous cercaria. We discovered sporocysts containing nonoculate trichocercous cercariae we identified as Cercaria rangiae Wardle, 1983, infecting the viscera of the Gulf wedge clam, Rangia cuneata (G. B. Sowerby I), in the Pascagoula River, Mississippi, U.S.A. We generated the internal transcribed spacer 2 (ITS2) region and a portion of the 28S rDNA gene from the new species and C. rangiae. Dissimilarity at both sequences demonstrated that the stages were not conspecific. Bayesian inference analyses applied separately to the ITS2 region, and the partial 28S rDNA gene, resulted in trees with similar topology, both depicting the new species and C. rangiae as sister taxa. The possible identity of C. rangiae and the phylogenetic relationships among species of Bacciger and related genera are discussed. We consider Bacciger lesteri Bray, 1982, and Bacciger sprenti Bray, 1982, incertae sedis in the Microphalloidea Ward, 1901. All other species of Bacciger, and species belonging in Pseudobacciger Nahhas and Cable, 1964, and Baccigeroides Dutta, 1995, are transferred from the Faustulidae to the Gymnophalloidea Odhner, 1905, where their familial affinities remain incertae sedis.

Some feline intestinal parasites such as Toxocara, Giardia, and Cryptosporidium can spread to humans through feces. Therefore, it is important to prevent exposure of family members by screening cat fecal samples twice per year for potential treatment regimes. This study was initiated to compare and identify gastrointestinal parasites of domestic and stray cats (Felis domesticus) in Baghdad City, Iraq. Parasite eggs and oocysts were identified under light microscopy by applying standard laboratory techniques (flotation and sedimentation). Overall, 59 of 121 (48.7%) fecal samples were positive for intestinal parasites. The rate of infection by Toxoplasma gondii was (3.31%), Isospora spp. (6.61%), Cryptosporidium spp. (31.4%), and Toxocara spp. (1.65%). Four percent of domestic and stray cats were infected with Isospora and Cryptosporidium and 2% were infected with Isospora, Cryptosporidium, and Toxoplasma. The prevalence of infected males (37%) was higher than for females (12%) during October and November. The prevalence of stray cats (30.5%) was higher than for domestic cats (18.8%) in February (45.4%). The diversity of parasites found during this study suggests that additional surveys and proper control programs are necessary to decrease the risk of zoonotic disease transmission.

In the present study, the zoonotic tapeworms Dibothriocephalus latus and Dibothriocephalus dendriticus were identified for the first time, using morphological and molecular procedures, in a population of introduced Chinook salmon in Chile. The morphological differences observed between plerocercoids of D. latus and D. dendriticus were, respectively, a retracted and obscured scolex versus one that is always visible and only partially retracted after cold fixation; extension of frontal glands; size, types of, density of, and distribution of microtriches; and number of parenchymal longitudinal muscle bundles within 50-µm spaces. With scanning electronic microscopy, both species presented 3 types of microtriches: coniform and uncinated spinitriches, and capilliform filitriches. In the body region, D. latus presents all types of microtriches, but D. dendriticus only possessed capilliform filitriches. Multiplex PCR targeting cox1 of Diphyllobothriidae and subsequent sequence analysis allowed for confirmation of species identity. All adult Chinook salmon examined (32–60 cm total length) were infected by Dibothriocephalus spp. with a range of 15–192 plerocercoids. Plerocercoids were found in the stomach, intestine, liver, spleen, gonads, swim bladder, peritoneum, heart, and muscles. The prevalence of infected salmon, the percentage of plerocercoids, and the mean intensity of D. latus in the muscles were 3, 4, and 2 times greater than that of D. dendriticus. Histological examination of the stomach, liver, spleen, gonads, and muscle revealed the presence of 1 or more encysted or free plerocercoids. In most cases, varying degrees of chronic inflammation and low presence of neutrophils were observed. The prey consumed by Chinook salmon included the native fish, Galaxias maculatus, and unidentified fish and amphipods. Other identified endohelminths were Derogenes lacustris Tsuchida, Flores, Viozzi, Rauque, and Urabe, 2021 in the stomach, Camallanus corderoi Torres, Teuber and Miranda, 1990 in the intestine, larvae of Contracaecum sp. in the intestinal wall, and Acanthocephalus tumescens (von Linstow, 1896) in the intestine. All identified parasites are reported for the first time in Chinook salmon from Chile.