Further evidence that zinc sulphate compromises the efficacy of dipping treatments using diazinon to control sheep lice (Bovicola ovis).

OBJECTIVE: To compare the wettability and efficacy of diazinon dip wash made with and without the addition of zinc sulphate. DESIGN: Field experiments using a shower and a plunge dip complemented by in-vitro wettability experiments. PROCEDURE: A flock of infested sheep was divided into groups and treated in a shower dip with clear or cloudy dam water plus up to 1.5% zinc sulphate. Another infested line of sheep was treated using a plunge dip with nil or 1% zinc sulphate. In both experiments, wetting was assessed after dipping and louse counts were conducted for 9 months after treatment. Five in-vitro experiments compared the wettability of dip wash containing diazinon with up to 1.5% zinc sulphate added. RESULTS: In the shower dipping experiment, live lice were found at 1 month after dipping in the cloudy water groups with 0.75%, 1.0% and 1.5% zinc sulphate and at 2 months in the 0.75% zinc sulphate group. No lice were found at subsequent inspections or at any time in the groups that were plunge dipped. Zinc sulphate decreased the amount of dip wash retained by wool staples in all in-vitro experiments (P < 0.05). CONCLUSION: Zinc sulphate should be considered as a risk factor that could cause failure to eradicate a lice infestation. The risk can be overcome by ensuring that all sheep are saturated at dipping and that the dip wash, and any holding tanks, are agitated throughout the dipping event.

The detection of lice (Bovicola ovis) in mobs of sheep: a comparison of fleece parting, the lamp test and the table locks test.

Knowledge of the presence or absence of lice in a flock of sheep enables wool growers to make informed decisions as to the need for insecticidal treatments. However, with inapparent infestations, traditional methods of detection are not sufficiently sensitive and, as a consequence, flocks may be left untreated. Conversely, the routine application of insecticide to sheep with no sign of infestation is an unnecessary cost. The sensitivity of 3 procedures for detecting lice was evaluated in 68 mobs of sheep from 50 farms. In 24 mobs of sheep known to be lightly infested, lice were detected in 17% (71%) [corrected] by either parting the fleece of 10 sheep or by the lamp test in which 8g samples of shorn wool from 30 randomly selected fleeces were placed under lamps for 10 min to repel the lice. Twenty of 23 mobs (87%) were found to be infested by the table locks test in which a 30 g sample of locks wool was dissolved in 10% sodium hydroxide and the filtered residue examined with x 40 magnification. A screening test, in which either fleeces on 5 sheep were examined by fleece parting or lice were repelled from 30 shorn fleeces for 5 minutes, detected about 60% of lightly infested mobs. When this was followed by the table locks test 91% of lightly infested mobs were detected. Conducting any one of the tests on more than one mob, and in large mobs testing more frequently, increases the sensitivity of detection of lice within the whole flock.

Settling of insecticide from dip wash mixed with dam water and zinc sulphate and used to control sheep lice (Bovicola ovis).

Insecticidal dipping fluid emulsions, mixed in vitro in dam water containing suspended clay particles and 1% w/v zinc sulphate, were analysed to determine rates of settling of diazinon, cyhalothrin and cypermethrin. Fifteen minutes after mixing, the concentration of the insecticides 5 cm below the surface had declined by 72.5%, 72.8% and 89.4%, respectively. On remixing, the concentration of insecticide in suspension was close to or greater than the initial concentration. In 2 trials, lice were eradicated from sheep showered with dip wash mixed in cloudy dam water to which 1% w/v of zinc sulphate was added. In 12 flock treatments in which 1000 to 2000 sheep were dipped with added zinc sulphate, the concentration of insecticide remained above the minimum lethal for susceptible strains of lice. However, lice were still present 6 months later in 8 of these flocks. When zinc sulphate is added to dip wash, agitation is needed to maintain the insecticide in suspension.

Emergency medical care in the athletes' village: World University Games 1993.

OBJECTIVE: Little information exists concerning special medical needs at the athletes' residence (as distinct from the sport venues) at major international sporting events. During the summer of 1993, Buffalo, New York became the first city in the United States to host the World University Games. Approximately 6,000 athletes and accompanying staff from 118 countries attended. This report seeks to characterize emergency medical care use and the degree of language difficulty encountered at the athletes' village medical center (AVMC) set up at the athletes' residence for this event. METHODS: Demographic data were collected prospectively for each athlete or staff member housed in the athletes' village who presented to AVMC for medical evaluation rather than being cared for by a team physician or at one of the venues. Difficulty in medical treatment secondary to language differences was assessed by the treating physician on a scale of 0-3. RESULTS: Over the 14 days that the AVMC was in operation, for 24 hours a day, a total of 362 athletes (mean age: 22.9 +/- 2.9 years, 257 males, 105 females) and 149 accompanying staff (mean age: 39.8 +/- 11.6 years, 110 males, 39 females) were treated. More than 90% of the patients were seen between the hours of 0800 and 2400. A broad spectrum of minor medical problems occurred, with musculoskeletal injuries accounting for most of the visits for both athletes (54%) and staff (27%). Nonsteroidal anti-inflammatory agents and oral antibiotics were the most commonly prescribed medications. On-site radiographic facilities were used for 22% of the athletes and 11% of the staff treated. The majority of patients (92% of athletes, 91% of staff) were discharged from the AVMC. Four of the 12 patients that were transferred to a hospital-based emergency department were admitted to the hospital. Language problems, as assessed by the treating physician, were mostly minor; 25% of the patients had accompanying interpreters. One volunteer physician, and two to three nurses adequately staffed each shift. CONCLUSION: The AVMC provided medical care for a large variety of medical problems that could be treated on-site without transfer to a higher-level facility, thereby providing directed medical care for this special population in a secure environment. Language differences were perceived as a minor problem. This report should be valuable in the planning of medical care at the athletes' residences for similarly large sporting events.

Persistence of the sheep body louse, Bovicola ovis, after treatment.

Lice were found in samples of baled wool from 198 of 464 flocks treated to eliminate an infestation in the period July 1988 to June 1990. In 287 flocks the insecticide was applied as a backline treatment and in 177 flocks a shower dip was used. Of these flocks, 41.5% and 44.6%, respectively, were found to be infested at the following shearing. After adjusting for the accuracy of the test, it was estimated that infestation in 2 consecutive 12-month periods occurred in 52.6% of flocks with a real incidence rate of 27.4%. Using these estimates, it was calculated that in 34.7% of infested flocks treatment did not kill all lice. There were no differences in the proportion of consecutive infestations between flocks treated with any of the 3 chemicals applied as backline treatments. Among flocks treated in a shower dip, 68.4% using coumaphos, 37.8% using diazinon and 41.5% using cyhalothrin had consecutive infestations (P < 0.05). The detection of lice in 63.2% of flocks that were treated with magnesium fluosilicate was, in part, attributed to the application of this chemical by one operator.

Incorporating an analysis of gender to the study of migration: the case of Peruvian migration patterns.

PIP: An analysis of rural-urban migration in Peru is presented, with the focus on women migrating to obtain work as domestic servants. Data are from published studies and a survey of 104 domestic servants interviewed in 1984.^ieng

A design methodology for nonlinear systems containing parameter uncertainty.

A design methodology capable of dealing with nonlinear systems containing parameter uncertainty is presented. A generalized sensitivity analysis is incorporated which utilizes sampling of the parameter space and statistical inference. For a system with j adjustable and k nonadjustable parameters, this methodology (which includes an adaptive random search strategy) is used to determine the combination of j adjustable parameter values which maximizes the probability of the performance indices simultaneously satisfying design criteria given the uncertainty in the k nonadjustable parameters.