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Viana L.A.,Instituto Oswaldo Cruz Fiocruz | Paiva F.,Instituto Oswaldo Cruz Fiocruz | Paiva F.,Laboratorio Of Parasitologia Veterinaria | Coutinho M.E.,Instituto Oswaldo Cruz Fiocruz | Lourenco-De-Oliveira R.,Instituto Oswaldo Cruz Fiocruz
Journal of Parasitology | Year: 2010

The prevalence and parasitemia of Hepatozoon caimani in the natural population of the caiman, Caiman yacare, from the Pantanal area, state of Mato Grosso do Sul, central Brazil, were evaluated according to gender and month of capture from July 2006 to February 2008. Blood samples were obtained bimonthly from a total of 229 caimans, and 76 were positive. Prevalence varied significantly according to sampling month and animal size. Almost all adults (100) and young-adults (97) were positive, while 63 of juvenile caimans were positive and all of the youngest individuals were negative. These results indicate that caimans are infected for the first time as juveniles. The mean parasitemia in blood was 13.5 ± 13.0 (n 174; 196 parasites) and did not significantly vary with respect to gender, month of sampling, size, or weight of the caiman. The frequency distribution of parasites in the caiman population was aggregated. Differences in feeding habits and exposure to vectors between the youngest caimans and juveniles are hypothesized as the main risk factors for caimans to acquire H. caimani in central Brazil. © American Society of Parasitologists 2010.


The tick Rhipicephalus (Boophilus) microplus is the most important ectoparasite in cattle rising, and it is responsible for severe economic losses. Parasite control is based on chemicals, which are used indiscriminately and result in effectiveness reduction of these compounds. In order to delay the onset of parasite resistance, some alternative methods are being researched, including herbal medicine. The aim of this experiment was to evaluate the in vitro efficacy of citronella (Cymbopogon nardus) oil and tincture on R. (B) microplus by the engorged female immersion test. Four oil concentrations were tested (1; 25; 50; 100%) and the inhibition of oviposition were 16; 40; 53; 73%, egg hatch were 28; 16; 23; 6% and the effectiveness were 78; 100; 86; 98%, respectively. The gradual rise of the inhibition of oviposition and low egg hatch had a positive influence in the effectiveness of treatment. The solution at 1% of citronella oil had a partial control of the teleogines and the solution at 25% had 100% of effectiveness. Six dilutions of the tincture (1; 5; 10; 25; 50; 100%) were tested and the inhibition of oviposition were 10; 63; 80; 83; 86; 96%, egg hatch were 91; 31; 6; 26; 0; 0% and the effectiveness were 23; 93; 94; 97; 100; 100%, respectively. Most of the treatments with the citronella tincture had inhibition of oviposition higher than 80% and low egg hatch rate. The tincture at 5% had similar efficacy compared to the groups with higher concentrations. A significant association between the oil and tincture of citronella and the treatment effectiveness was observed in the statistical evaluation. It is possible to conclude that both the oil and the tincture of citronella had negative influence in the reproductive parameters of R. (B) microplus.

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