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Pesq. Vet. Bras. 29(3):253-257, março 2009 RESUMO.-[Inquérito sobre práticas de manejo e controle das helmintoses em éguas no Brasil.] Vinte nove haras foram selecionados na região do Médio Paraíba, Estado do Rio de Janeiro, os responsáveis pelos animais entrevistados e amostras fecais de éguas foram coletadas e submetidas às técnicas de OPG, Coprocultura, Sedimentocentrifugo-flutuação, Ueno e Baermann modificadas. A prevalência dos helmintos para as éguas e haras foi calculada. A capacidade de suporte, a troca de cama nas baias, a ausência da rotação do pasto, a ausência do tecnificação na propriedade e menor freqüência do tratamento dos animais foram associadas à prevalência maior dos helmintos, indicando que estas variáveis devem ser consideradas em programas de controle dos helmintos de eqüinos. A intensidade do parasitismo foi também associado à capacidade de suporte do pasto, à ausência de esterqueira, à presença dos animais somente nos pastos, à ausência do tecnificação na propriedade, à menos freqüência do tratamento e à ausên-cia de uso da rotação da classe anti-helmintica. TERMOS DE INDEXAÇÃO: Praticas de manejo e controle, helmintos, tratamento, eqüinos. INTRODUCTIONInternal parasites are a significant threat to the health of horses. Horses are susceptible to more than 60 internal parasites and may harbor several species of worms at any time. (Stoltenow & Purdy 2003). Helminths are an important cause of morbidity and mortality in equines, and the prevalence of infection with these parasites is high enough to clinical parasitism (Proudman & Mattews 2000). In Brazil, in spite of the enormous population of horses, there are few studies on equine helminth control. Also, limited information is available concerning risk factors for worm infection. Twenty-nine stud farms were selected in the Medium Paraíba region of the Rio de Janeiro state, Brazil. After an interview with the person responsible for the animals, faecal samples were collected from mares and analyzed via the EPG technique, faecal cultures, Sedimentation-centrifugo-flotation, and modified Ueno and Baermann techniques. The prevalence of helminths in the mares and in the stud farms was calculated. The stocking rates of pasture, change of horse bedding, absence of pasture rotation, absence of technology in the property, and less frequent treatment of the animals were associated with a greater prevalence of helminths, showing that these variables must be considered in equine control programs. The intensity of the parasitism was also associated with the stocking rate of pasture, absence of dunghill, presence of the animals only in paddocks, lack of technology in the property, less frequent treatment of the animals, and absence of the use of rotation regarding the anthelmintic class.

The purpose of our study was to evaluate the larvicidal efficacy of nitenpyram for the treatment of screwworm myiasis caused by Cochliomyia hominivorax in naturally infested dogs. Seven Beagle dogs presenting with myiasis were treated with nitenpyram twice at an interval of 6 h. The animals received dosages between 1.43 and 4.42 mg/kg body weight of nitenpyram in each given treatment. The criteria used to determine the drug efficacy were larval expulsion and fall. These were quantified at 15 min intervals within the first hour followed by 2, 3, 4, 6, and 18 h post-treatment. The highest larval expulsion happened between 1 and 2 h post-treatment. The spontaneous larval expulsion percentages were 86% and 94.11% for 6 and 18 h after the first treatment, respectively. Larvae were expelled until 18 h post-treatment. After this period the remaining dead larvae were mechanically removed. Nitenpyram showed 100% efficacy on the treatment of myiasis by C. hominivorax in naturally infested dogs.

Metarril SP Organic is a product based on the fungus Metarhizium anisopliae, which was developed for controlling agricultural pests. The present study evaluated the effect of Metarril SP Organic plus 10% mineral oil, for controlling Rhipicephalus microplus under field conditions. Three groups were formed: Control group, which received no treatment; Oil control group, which was bathed only with water, Tween 80 and mineral oil; and Metarril group, bathed in the oil-based formulation Metarril SP Organic. Two treatments per group were performed and to verify the effect of the treatments, all R. microplus ticks between 4.5 and 8.0mm in length on the left side of the cattle were counted on days +7, +14 and +21 after each treatment, and a sample of engorged females was collected for evaluation of biological parameters. The Metarril SP Organic oil formulation showed efficacy ranging from 8.53 to 90.53%. The average efficacy of the oil-based formulation of Metarril SP Organic was 75.09 and 46.59% compared with the groups Control and Oil control, respectively. There were no significant changes in biological parameters of engorged R. microplus females collected from animals. Although there was no significant difference in the amount of ticks between the Oil control and Metarril groups, it is believed that the association of mineral oil with Metarril SP Organic product is effective in R. microplus tick control in field. Thus, this association has potential to be used in strategic control programs of cattle tick.

The objectives of this study were (i) to evaluate the effects of several different disinfectant solutions on embryonic development of Toxocara canis eggs and (ii) to investigate the potential infectivity of exposed eggs by assessing larval establishment in various tissues in a murine model. All the disinfectants tested were products routinely used in veterinary clinics, kennels, animal shelters and laboratories. Ova were obtained from gravid female T. canis uteri. Thirty samples containing 10,000 eggs were divided into five groups of six identical sample tubes per group. The treatments for the groups were as follows: Group H benzalconium chloride, Group A 70% ethanol, Group B 2-2.5% sodium hypochlorite solution, Group L 7.99% formaldehyde-based disinfectant and Group C tap water (controls). Samples were incubated at 27 ± 1°C and 80 ± 10% relative humidity. Embryonic development was evaluated on days +6, +9, +12, +15, +18, +21, +25, +28 and +36 of exposure by visual observation under light microscopy. Seventy percent ethanol degenerated all eggs within a few days and thus inhibited larval development. Sodium hypochlorite removed the external layer of the ova, but eggs harboured infective larvae for up to 2 weeks. Benzalconium chloride and formaldehyde-based disinfectants had no effect on T. canis embryogenesis according to comparison with control eggs (P > 0.05). Embryonated eggs from each of the six samples from Groups C, H and L were administered to mice as only these ova were considered viable based on in vitro trial. On day 30pi, those were euthanized and had their tissues were submitted to organ compression (brains) or acid-isolation technique (kidneys, lungs, livers and carcasses) for larval counting. The mean number of recovered larvae for Groups C, H and L were: 512.8, 393.7 and 477 respectively (P > 0.05). Larvae derived from Groups H and L eggs maintained their ability to migrate. However, larval establishment pattern differed from control. While certain disinfectants do negatively affect embryogenesis (70% ethanol) and reduce the integrity and durability (sodium hypochlorite) of infective T. canis eggs, others have no effect upon embryogenesis. Those eggs can still be a threat to human and animal health even after over a month of disinfectant exposure.