Communities of parasite metazoans in Piaractus brachypomus (Pisces, Serrasalmidae) in the lower Amazon River (Brazil).

The aim of this study was to investigate the component community of parasite metazoans of Piaractus brachypomus in the lower Amazon River, northern Brazil. From 34 necropsied fish, 27,384 metazoan parasites were collected, such as Anacanthorus spathulatus, Mymarothecium viatorum and Notozothecium janauachensis (Monogenoidea); Spectatus spectatus and Contracaecum sp (Nematoda); Clinostomum marginatum and Dadaytrema oxycephala (Digenea); and Argulus carteri and Ergasilus sp. (Crustacea). The dominant species was S. spectatus followed by monogenoidean species, and there was aggregated dispersion of parasites, except for D. oxycephala and Contracaecum sp., which presented random dispersion. Positive correlation among the abundance of the three monogenoideans species were found, thus indicating that there was no competition between the species of these parasites on the gills of hosts. The abundances of some parasite species showed positive correlations with the size of the hosts, but the condition factor of the fish was not affected by the parasitism levels. It showed that this host had a metazoan community characterized by high species richness of metazoans, low evenness and high diversity of parasites, with prevalence of endoparasites, including larval stages. This was the first record of C. marginatum, A. carteri, Ergasilus sp. and Contracaecum sp. for P. brachypomus.

Parasite communities of the predatory fish, Acestrorhynchus falcatus and Acestrorhynchus falcirostris, living in sympatry in Brazilian Amazon.

This study investigated the parasite communities of wild Acestrorhynchus falcatus and Acestrorhynchus falcirostris populations living in sympatry in Brazilian Amazon. In these two hosts, a total of 12 parasite species e 1-9 parasite species were found per fish, and 10 of these species are metazoans. Eight species of parasites were common to both host species and four of them exhibited differences in abundance and/or prevalence. Parasite communities of the hosts were taxonomically similar (83%) and composed of both ectoparasites and endoparasites, and characterized by high prevalence and high abundance of endoparasites and an aggregated dispersion pattern. For A. falcirostris, the dominant parasite was Ichthyophthirius multifiliis, and for A. falcatus, it was Piscinoodinium pillulare. Shannon diversity and Berger-Parker dominance were similar for both hosts, while the parasites species richness and evenness showed differences influenced by the ectoparasites species. These two populations of hosts that inhabited the same geographical area had different sizes, but were exposed to the same infective stages, and acquired qualitatively and quantitatively similar endoparasites community, thus indicating that the amounts and types of prey congeneric that they were eating were similar. Therefore, the overlap in the same occurrence area play an important role in the parasite communities to these phylogenetically related hosts.

In vitro effects of Pilocarpus microphyllus extracts and pilocarpine hydrochloride on Rhipicephalus (Boophilus) microplus.

The aim of this study was to assess the activity of aqueous (AE) and ethanolic extracts (EE) and pilocarpine hydrochloride, which were extracted and isolated from Pilocarpus microphyllus (Jaborandi), respectively, on Rhipicephalus (Boophilus) microplus. High performance liquid chromatography (HPLC) was performed to quantify these compounds. Larval packet and adult immersion tests were conducted with different concentrations. Five AE and EE concentrations, ranging from 6.2 to 100.0 mg mL?1, and six concentrations of pilocarpine hydrochloride, ranging from 0.7 to 24.0 mg mL?1, were tested. The lethal concentration (LC50) of each extract for larvae and engorged females was calculated through Probit analysis. The concentration of pilocarpine hydrochloride obtained from the EE and the AE was 1.3 and 0.3% (m/m), respectively. Pilocarpine hydrochloride presented the highest acaricidal activity on larvae (LC50 2.6 mg mL?1) and engorged females (LC50 11.8 mg mL?1) of R.(B.) microplus, followed by the EE which presented LC50 of 56.4 and 15.9 mg mL?1, for larvae and engorged females, respectively. Such results indicate that pilocarpine hydrochloride has acaricidal activity, and may be the primary compound responsible for this activity by P. microphyllus EE.

Design of the ATAQ peptide and its evaluation as an immunogen to develop a Rhipicephalus vaccine

2016

Molecular survey and genetic characterization of tick-borne pathogens in dogs in metropolitan Recife (north-eastern Brazil).

To identify DNA of the main tick-borne pathogens in dogs from Recife (Brazil), polymerase chain reactions were carried out on blood samples of dogs treated at the Veterinary Hospital of the Universidade Federal Rural de Pernambuco from March 2007 to June 2008. The detection of DNA was performed using specific primers. Amplicons were analyzed through electrophoresis and sequencing. A phylogenetic tree was constructed using the UPGMA method, revealing that the sequences were closely related to those of strains from other geographic regions. Among the 205 blood samples analyzed, 48.78% was positive for Anaplasma platys; 38.04% was positive for Ehrlichia canis; 7.31% was positive for Babesia canis vogeli; and 0.49% was positive for Hepatozoon canis and Mycoplasma haemocanis. Coinfection of two or three pathogens was found in 23.9% (49/205) of the dogs. The subspecies B. canis vogeli was identified. Infection by H. canis and M. haemocanis is reported for the first time in dogs in the state of Pernambuco (Brazil). The data indicate that the main tick-borne pathogens in dogs in this region are E. canis and/or A. platys, followed by B. canis vogeli.