Dioctophyme renale: in vitro culture, production of excretory and secretory antigens, and their use in immunodiagnosis.

The nematode Dioctophyme renale affects mainly the right kidney of domestic and wild mammals, in addition to having zoonotic potential. Therefore, this study aimed to produce excretion and secretion antigens of adult D. renale (DES) to diagnose canine dioctophimosis. To obtain the excretion and secretion antigens (DES), five D. renale adults were maintained for three weeks in supplemented RPMI medium with weekly supernatant collections. After the DES concentration, 2200 mL of the collected supernatant was used, which was centrifuged, followed by two filtrations and dialyzed, resulting in 12.5 mL of DES with a protein concentration of 0.59 mg/mL. The polyacrylamide gel electrophoresis (SDS-PAGE) of the DES antigen showed fractions with molecular weights ranging from 30 to 250 Kda. In the indirect ELISA with the DES antigen, the mean absorbance of the positive sera (38) was 0.839 ± 0.267, and the mean of the negative control sera (7) was 0.208 ± 0.083; the specificity and sensitivity of the ELISA were 100 and 97.4 %, respectively, being as effective as the surgical method in the presence of viable parasites. Thus, for the first time, this study describes the production of excretion and secretion antigens of adult D. renale and standardizes an indirect ELISA to diagnose dioctophimosis.

Ovicidal activity of the hydroalcoholic extract of Brazilian peppertree (Schinus terebinthifolia Raddi) against Ancylostoma spp. from naturally parasitized dogs.

This study aimed to evaluate the ovicidal activity of the hydroalcoholic extract of Schinus terebinthifolia (SCH; T1) against Ancylostoma spp. and its influence of storage time in the extract stored for 36 months (T36). Eggs of Ancylostoma spp. were obtained from naturally parasitized dogs, and used for the larval hatchability test, where the eggs were exposed to T1 and T36 extracts of SCH (15-0.625 mg/mL). In T1, all concentrations inhibited more than 80% of the eggs, being 100% at concentrations between 15 and 5 mg/mL (p > 0.05). At T36, all concentrations were active, even the ones between 2.5 and 0.625 mg/mL, with 100% inhibition (p < 0.05), revealing that the storage time maintained the ovicidal action. By LC-MS, T36 presented ethyl gallate, myricitrin, and gallic acid as major compounds. These findings support the promising use of SCH extract as an ovicide against Ancylostoma spp., even stored for 36 months of shelf life.

Controlling gastrointestinal nematodes in cattle by Bacillus species.

In this study, we tested the in vitro and in vivo larvicidal activity of Bacillus species against gastrointestinal nematodes in cattle, and their viability in the presence of anthelmintics. For in vitro tests, cattle feces naturally infected with trichostrongylides were incubated with spore suspensions of Bacillus circulans (Bcir), B. thuringiensis var. osvaldocruzi (Bto), B. thuringiensis var. israelensis (Bti) or B. thuringiensis var. kurstaki (Btk). Subsequently, residual larvae were counted and identified. All of the Bacillus species showed 60% or more larvicidal effects. Bcir and Bti were selected to be incubated with anthelmintics (moxidectin, nitroxynil and levamisole), and after 24, 72, and 144h, their viability was evaluated. Bti showed highest drug resistance, maintaining a concentration of 1×107CFU/mL. Based on this result, Bti was selected for in vivo tests on calves naturally infected with gastrointestinal nematodes. The calves were dived into four groups: Group 1, Bti suspension of ∼1×109CFU orally administered; Group 2, Bti suspension of ∼1×109CFU orally administered with levamisole (subcutaneously, 150mg); Group 3, only levamisole (subcutaneously, 150mg), and Group 4 untreated. Then 24 and 48h after treatment, larvae numbers were counted. We observed a reduction of 84%, 100%, and 100% after 48h of treatment, respectively, for Groups 1, 2 and 3 treatments in comparison with the untreated. The tested Bacillus species showed larvicidal activity against bovine trichostrongylides, and its association with anthelmintics. It may serve as a promising integrated alternative for control of gastrointestinal nematodes in cattle.