Comparison between McMaster and Mini-FLOTAC methods for the enumeration of Eimeria maxima oocysts in poultry excreta.

Monitoring Eimeria shedding has become more important due to the recent restrictions to the use of antibiotics within the poultry industry. Therefore, there is a need for the implementation of more precise and accurate quantitative diagnostic techniques. The objective of this study was to compare the precision and accuracy between the Mini-FLOTAC and the McMaster techniques for quantitative diagnosis of Eimeria maxima oocyst in poultry. Twelve pools of excreta samples of broiler chickens experimentally infected with E. maxima were analyzed for the comparison between Mini-FLOTAC and McMaster technique using, the detection limits (dl) of 23 and 25, respectively. Additionally, six excreta samples were used to compare the precision of different dl (5, 10, 23, and 46) using the Mini-FLOTAC technique. For precision comparisons, five technical replicates of each sample (five replicate slides on one excreta slurry) were read for calculating the mean oocyst per gram of excreta (OPG) count, standard deviation (SD), coefficient of variation (CV), and precision of both aforementioned comparisons. To compare accuracy between the methods (McMaster, and Mini-FLOTAC dl 5 and 23), excreta from uninfected chickens was spiked with 100, 500, 1,000, 5,000, or 10,000 OPG; additional samples remained unspiked (negative control). For each spiking level, three samples were read in triplicate, totaling nine reads per spiking level per technique. Data were transformed using log10 to obtain normality and homogeneity of variances. A significant correlation (R = 0.74; p = 0.006) was observed between the mean OPG of the McMaster dl 25 and the Mini-FLOTAC dl 23. Mean OPG, CV, SD, and precision were not statistically different between the McMaster dl 25 and Mini-FLOTAC dl 23. Despite the absence of statistical difference (p > 0.05), Mini-FLOTAC dl 5 showed a numerically lower SD and CV than Mini-FLOTAC dl 23. The Pearson correlation coefficient revealed significant and positive correlation among the four dl (p ≤ 0.05). In the accuracy study, it was observed that the Mini-FLOTAC dl 5 and 23 were more accurate than the McMaster for 100 OPG, and the Mini-FLOTAC dl 23 had the highest accuracy for 500 OPG. The McMaster and Mini-FLOTAC dl 23 techniques were more accurate than the Mini-FLOTAC dl 5 for 5,000 OPG, and both dl of the Mini-FLOTAC were less accurate for 10,000 OPG counts than the McMaster technique. However, the overall accuracy of the Mini-FLOTAC dl 23 was higher than the McMaster and Mini-FLOTAC dl 5 techniques.

Experimental Life-Cycle of Varestrongylus eleguneniensis (Nematoda: Protostrongylidae) in a Captive Reindeer (Rangifer tarandus tarandus) and a Muskox (Ovibos moschatus moschatus).

The life-cycle of a recently described protostrongylid lungworm, Varestrongylus eleguneniensis, which infects caribou, muskoxen, and moose from Arctic and boreal regions of North America, was completed experimentally for the first time. A native North American slug species, Deroceras laeve, was infected with the first-stage larvae (L1) isolated from the feces of wild muskoxen to generate third-stage larvae (L3). These were administered to a captive reindeer calf (250 L3) and an adult captive muskox (380 L3). The prepatent periods for the reindeer and muskox were 56 and 72 days, respectively. Patency lasted for only 19 days in the reindeer, and fecal larval counts were very low (0.09-1.53 larvae per gram of feces). Patency in the muskox was at least 210 days, and likely over 653 days, and the fecal larval counts were higher (0.06-17.8 larvae per gram of feces). This work provides the first experimental completion of the life-cycle of V. eleguneniensis.

Identification of semiochemicals attractive to Simulium vittatum (IS-7).

Many blackfly species (Diptera: Simuliidae) are economically important insect pests, both as nuisance biters and as vectors of pathogens of medical and veterinary relevance. Among the important blackfly pest species in North America is Simulium vittatum Zetterstedt sensu lato. The objective of this study was to identify compounds excreted by mammalian hosts that are attractive to host-seeking S. vittatum females. The attractiveness of putative compounds to colonized S. vittatum was tested through electrophysiological (electroantennography; n = 58 compounds) and behavioural (Y-tube assays; n = 7 compounds in three concentrations) bioassays. Five compounds were significantly attractive to host-seeking S. vittatum females: 1-octen-3-ol; 2-heptanone; acetophenone; 1-octanol, and naphthalene. These candidate compounds might be useful as attractants in traps that could be developed for use in alternative or complementary management tactics in programmes to suppress nuisance blackfly populations, or for the collection of samples in which to study the transmission ecology of pathogens transmitted by blackflies of the S. vittatum complex.

Effects of disinfectants on Toxocara canis embryogenesis and larval establishment in mice tissues.

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.

Efficacy of cypermethrin on the control of Struthiolipeurus spp. (Phthiraptera: Philopteridae) in ostrich / Eficácia da cipermetrina no controle de Struthiolipeurus spp. (Phthiraptera: Philopteridae) em avestruz

Duzentos e quarenta avestruzes, com idades entre 12 e 24 meses, foram examinados quanto ao parasitismo por Struthiolipeurus spp. Destes, 168 apresentavam-se infestados por piolhos (70 por cento). Todas as aves foram tratadas com solução de cipermetrina a 15 por cento, na diluição de 1ml/l, por pulverização com auxílio de uma bomba costal. Os animais positivos foram reexaminados nos dias 7, 14 e 21 após o tratamento, e não foram mais encontrados piolhos. A cipermetrina apresentou 100 por cento de eficácia no controle de piolhos do gênero Struthiolipeurus em avestruz.

Occurrence of Struthiopterolichus bicaudatus (Acari; Pterolichidae) in Southeastern Brazil

A ocorrência de Struthiopterolichus bicaudatus é assinalada em uma criação de avestruz no estado de Minas Gerais. Os principais sinais associados com a presença dos ácaros foram penas quebradas com a falta de barbas no vexilo, principalmente nas penas das asas, e prurido. Esses sinais foram observados em todas as aves do plantel (285 animais) com idade acima de 13 meses. As aves com idade abaixo de 13 meses (60 animais) não apresentaram qualquer sinal, tampouco ácaros.