Molecular analysis reveals the diversity of Hepatozoon species naturally infecting domestic dogs in a northern region of Brazil.

This study aimed to optimize molecular methods for detecting DNA of Hepatozoon spp. as well as identify the phylogenetic relationships of Hepatozoon strains naturally infecting domestic dogs in Belém, Pará, northern Brazil. Blood samples were collected from 138 dogs, and screened for Hepatozoon spp. using a new nested PCR assay. Positive samples were subjected to genetic characterization based on amplification and sequencing of approximately 670bp of the Hepatozoon spp. 18S rRNA. Of the positive dogs, four shared the haplotype Belém 01, one dog presented the haplotype Belém 02 and two dogs shared the haplotype Belém 03. A Bayesian inference indicates that haplotypes Belém 01 and Belém 02 are phylogenetically related to H. canis, while Belém 03 is related to H. americanum. Overall, based on the first molecular evidence of H. americanum in Brazilian domestic dogs, the proposed protocol may improve the epidemiological investigation of canine hepatozoonosis.

The morphology of free-living stages and immature parasites of Rhabdias paraensis (Nematoda: Rhabdiasidae), a parasite of Rhinella marina (Anura: Bufonidae) in Brazil.

Rhabdias paraensis Santos, Melo, Nascimento, Nascimento, Giese et Furtado, 2011 was described based on fully gravid worms. Further investigations on the free-living stages, immature worms and young individuals were facilitated by cultivation in the laboratory, which allowed us to add new information about the morphology and development of the species. Observations on the free-living development of R. paraensis showed that the life cycle is typical of Rhabdias, with alternation of gonochoristic and hermaphroditic generations and without homogony. Males of the free-living generation were different from those in several species of the genus studied previously. In the original description, the excretory glands and duct were absent in gravid specimens of R. paraensis, while in this study, distinct excretory glands and a duct were observed in immature and young individuals. Additionally, we recognised the separation of the buccal capsule walls into anterior and posterior portions and described the specific shapes of these portions in lateral and apical view. Studies on the morphology and development of free-living stages of Rhabdias spp. from Neotropical regions may provide additional information for species determination.

Description of Rhabdias breviensis n. sp. (Rhabditoidea: Rhabdiasidae) in two Neotropical frog species.

Nematodes of the genus Rhabdias Stiles & Hassall, 1905 (Rhabditoidea: Rhabdiasidae) have a dioecious free-living stage and a hermaphroditic stage that parasitises the lungs of amphibians and reptiles. Approximately 94 species of Rhabdias have been described. Because the similar morphological characteristics such as the labial structures, the location of the vulva and the shape of the tail of Rhabdias spp. hinder their identification, molecular biology techniques and scanning electron microscopy have been employed to diagnose species of this genus. This study describes Rhabdias breviensis n. sp., parasitic in the lungs of two Neotropical frog species Leptodactylus petersii Steindachner and Leptodactylus macrosternum Miranda-Ribeiro. The description of this species integrates classical taxonomy, scanning electron microscopy and a molecular analysis of the mitochondrial COI gene. The new species differs from all other Rhabdias species parasitic in Neotropical hosts in certain morphometric parameters, the position of the vulva, the host group and the cephalic characters.