Enrofloxacin is able to control Toxoplasma gondii infection in both in vitro and in vivo experimental models

Currently, toxoplasmosis is treated with sulfadiazine and pyrimethamine. However, this treatment presents several adverse side effects; thus, there is a critical need for the development and evaluation of new drugs, which do not present the same problems of the standard therapy. Enrofloxacin is a fluoroquinolone antibiotic known to control infection against several bacteria in veterinary medicine. Recently, this drug has demonstrated protective effects against protozoan parasites such as Neospora caninum. The present study aimed to determine the effect of enrofloxacin in the control of Toxoplasma gondii infection. For this purpose, human foreskin fibroblast (HFF) cells were infected with T. gondii RH strain and treated with sulfadiazine, penicillin/streptomycin, pyrimethamine, or enrofloxacin. Following treatment, we analyzed the infection index, parasite intracellular proliferation and the number of plaques. Additionally, tissue parasitism and histological changes were investigated in the brain of Calomys callosus that were infected with T. gondii (ME49 strain) and treated with either sulfadiazine or enrofloxacin. Enrofloxacin was able to reduce the infection index, intracellular proliferation and the number of plaques in HFF cells infected by T. gondii in comparison with untreated or penicillin/streptomycin-treated ones. Enrofloxacin was more protective against T. gondii in HFF infected cells than sulfadiazine treatment (P<0.001). In addition, pyrimethamine, enrofloxacin or the associations of sulfadiazine plus pyrimethamine, enrofloxacin plus sulfadiazine or enrofloxacin plus pyrimethamine-treatments were able to reduce the plaque numbers in HFF cells infected by T. gondii when compared to medium, penicillin/streptomycin or sulfadiazine alone. In vivo experiments demonstrated that enrofloxacin diminished significantly the tissue parasitism as well as the inflammatory alterations in the brain of C. callosus infected with T. gondii when compared with untreated animals. Based on our findings, it can be concluded that enrofloxacin is a potential alternative drug for the treatment of toxoplasmosis.     

Effects of cyclophosphamide myelosuppression in adult dogs with latent canine herpesvirus-1 infection

Latent canine herpesvirus-1 (CHV-1) infection is common in domestic dogs, but triggers for viral reactivation and recrudescent CHV-1 disease are poorly understood. Cyclophosphamide is a potent immunosuppressive and myelosuppressive agent used for the therapy of a variety of neoplastic and immune-mediated canine disorders. Cyclophosphamide (200mg/m(2)) was administered to mature dogs latently infected with CHV-1 to determine its potential to induce recurrent CHV-1 disease and viral shedding. Non-infected dogs and dogs recovered from experimental primary ocular CHV-1 infection with experimentally confirmed latent CHV-1 infection were divided into groups and administered cyclophosphamide or placebo. Dogs were monitored for myelosuppression and viral reactivation for 28days using clinical and virological outcome measures. Clinical ophthalmic and in vivo ocular confocal microscopic examinations were performed at intervals. Samples were collected for CHV-1 polymerase chain reaction (PCR), CHV-1 virus neutralizing (VN) antibody, and hemogram assays. Myelosuppression (i.e., decreased total leukocyte, segmented neutrophil, and erythrocyte counts) was detected on study day 7 in dogs administered cyclophosphamide, but not dogs administered placebo. There were no abnormalities suggestive of recurrent CHV-1 ocular disease during clinical ophthalmic or in vivo confocal microscopic examination in any dogs during the study. Ocular CHV-1 shedding was not detected by PCR and CHV-1 VN titers remained stable in all dogs. Following study conclusion, the presence of reactivatable latency was reconfirmed in the infected dogs by administering systemic prednisolone. Myelosuppression elicited by a single dose of cyclophosphamide does not result in detectable recurrent ocular CHV-1 infection in adult dogs with experimentally induced latent CHV-1 infection.     

Multiple strains of Mycobacterium bovis revealed by molecular typing in a herd of cattle

Mycobacterium bovis isolates from an outbreak of bovine tuberculosis in a herd of cattle in Rio de Janeiro, Brazil, were analysed by spoligotyping and variable-number tandem repeat PCR analysis of the mycobacterial interspersed repetitive unit and exact tandem repeats. Molecular typing revealed a high genetic diversity of strains in the herd. The genetic diversity could be explained by the introduction of infected animals from different sources.     

Comparative study of hematological parameters of Colossoma macropomum anesthetized with benzocaine and eugenol by using different anticoagulants

Aquaculture International - The objective of the present study was to evaluate the action of benzocaine and eugenol over anesthesia stages and the use of three anticoagulants (ethylenediamine...     

The effects of açaí oil addition in tilapia diets on performance,hepatic energy metabolism enzymes and antioxidant responses

The aim of the present study was to determine whether açai oil (Euterpe oleraceae) addition in the diets of juvenile Nile tilapia (Oreochromis niloticus) in biofloc system would stimulate hepatic energy metabolism and antioxidant responses. Treatments are as follows: T0 (6%‐soybean oil), T1 (1%‐AÇAI; 5%‐SOY), T3 (3% AÇAI; 3%‐SOY) and T6 (6%‐AÇAI). In the liver, reactive oxygen species levels were significantly lower in T1, T3 and T6 than in T0, lipid peroxidation levels were significantly lower in T3 and T6, and nitric oxide levels were significantly lower in the T6 than in T0. Glutathione peroxidase activity was significantly higher in the T3 and T6 than in T0, while superoxide dismutase activity and total antioxidant capacity levels were significantly higher in the T6 than in T0. Adenylate kinase activity was significantly lower in the T6 than in T0. These results suggest that the açai oil addition in Nile tilapia diets stimulated antioxidant responses.     

Biological control of horse cyathostomin (Nematoda: Cyathostominae) using the nematophagous fungus Duddingtonia flagrans in tropical southeastern Brazil

The viability of a fungal formulation using the nematode-trapping fungus Duddingtonia flagrans was assessed for the biological control of horse cyathostomin. Two groups (fungus-treated and control without fungus treatment), consisting of eight crossbred mares (3–18 years of age) were fed on Cynodon sp. pasture naturally infected with equine cyathostome larvae. Each animal of the treated group received oral doses of sodium alginate mycelial pellets (1 g/(10 kg live weight week)), during 6 months. Significant reduction (p < 0.01) in the number of eggs per gram of feces and coprocultures was found for animals of the fungus-treated group compared with the control group. There was difference (p < 0.01) of 78.5% reduction in herbage samples collected up to (0–20 cm) between the fungus-treated group and the control group, during the experimental period (May–October). Difference of 82.5% (p < 0.01) was found between the fungus-treated group and the control group in the sampling distance (20–40 cm) from fecal pats. During the last 3 months of the experimental period (August, September and October), fungus-treated mares had significant weight gain (p < 0.01) compared with the control group, an increment of 38 kg. The treatment with sodium alginate pellets containing the nematode-trapping fungus D. flagrans reduced cyathostomin in tropical southeastern Brazil and could be an effective tool for biological control of this parasitic nematode in horses.     

Evolution of rabbit haemorrhagic disease virus (RHDV) in the European rabbit (Oryctolagus cuniculus) from the Iberian Peninsula

To date information on rabbit haemorrhagic disease virus (RHDV) in Spain and Portugal has been scarce, although the disease is endemic and continues to have a considerable impact on species conservation and hunting industry. We analysed RHDVs obtained between 1994 and 2007 at different geographic locations in Portugal (40 samples), Spain (3 samples) and France (4 samples) from wild European rabbits (Oryctolagus cuniculus) that succumbed to the disease. Phylogenetic analyses based on partial VP60 gene sequences allowed a grouping of these RHDVs into three groups, termed "Iberian" Groups IB1, IB2 and IB3. Interestingly, these three Iberian groups clustered separately, though not far from earlier RHDVs of Genogroup 1 (containing e.g., strain "AST89"), but clearly distinct from globally described RHDV strains of Genogroups 2-6. This result, supported by a bootstrap value of 76%, gives rise to the hypothesis that the virus evolved independently since its introduction to wild rabbit populations on the Iberian Peninsula, with the Pyrenees acting as a natural barrier to rabbit and hence to virus dispersal. No differences were observed in RHDV sequences obtained from geographic regions where the rabbit subspecies O. c. algirus prevails compared with those obtained from O. c. cuniculus.