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Biomedical subjects

P J James

Publications and source records attributed to P J James.

At least 19 recordsLinked to original sources
PubMed2004

The prevalence of lice on sheep and control practices in South Australia.

OBJECTIVE: To assess the prevalence of infestations of lice in sheep flocks and to survey control practices for lice in South Australia DESIGN: A total of 201 managers of sheep flocks, 75 chosen randomly from the high rainfall zone (HR), 76 from the cereal sheep zone (CS) and 50 from the pastoral zone (PA), were surveyed by telephone interview. PROCEDURE: Interviews were conducted between May 19 and May 25, 1999, according to a set questionnaire. Information was collected on presence of lice at last shearing, control practices for lice, factors important for gaining good effect from chemical treatments, sources of information on control practices and property details. Survey results were analysed by agricultural region. RESULTS: The apparent state prevalence of flocks infested with lice was 21%, with 13% infested in the HR, 21% in the CS and 25% in the PA. Ninety one percent of managers claimed to take precautions to prevent the introduction of lice and 91% routinely checked their flocks for lice. Seventy eight percent treated their sheep for lice annually and 85% had treated within the last 12 months. Of those treating in the last year, 69% had used a backline application, 16% had used a shower dip and 17% had used plunge dipping. Only 4% of producers used a long wool treatment. Synthetic pyrethroid (SP) based products were used by 50% of producers who used backline treatments in the preceding 12 months, compared to 42% and 8% for insect growth regulator and organophosphorous (OP) based products, respectively. Only 34% of managers identified SP-based products as having potential resistance problems. Of those producers who used shower or plunge dips in the last 12 months, 75% used an OP based product. Rural newspapers and magazines were by far the most commonly noted source of information for the control of lice on sheep.

Animal Husbandry↗
PubMed2002

Variation among Merino sheep in susceptibilty to lice (Bovicola ovis) and association with susceptibility to trichostrongylid gastrointestinal parasites.

Sheep of two bloodlines of Merino were artificially infested with equal numbers of lice (Bovicola ovis) and the resulting louse populations were monitored over the following 20 months. The sheep were shorn 6 and 17 months after infestation and, for analysis, the louse counts considered in 3 years separated by shearings. Nematode faecal egg counts (FECs) were assessed on faecal samples collected on five occasions, three times following natural challenge and twice after artificial challenge with 40,000 trichostrongyloid larvae (84% Trichostrongylus vitrinus). In addition, blood samples were collected and measured for B. ovis-specific immunoglobulins (predominantly IgG), B. ovis-specific IgE and serum total IgE. Bloodlines differed significantly in the size of louse populations at the end of year 2, FEC after both natural and artificial challenge and in serum levels of all three antibodies (p<0.05). There were also large variations in louse counts and FEC among sheep within bloodlines. Louse counts at inspections after louse populations had been allowed to build up were highly repeatable, both between and within years. However, correlations with counts at inspections soon after initial infestation and following shearing were lower. FEC after natural challenge was correlated with louse counts in year 2 (r=0.45, p<0.01) and year 3 (r=0.38, p<0.05), but the correlation with counts in year 1 was not significant (r=0.25, p>0.05). FEC following artificial challenge was significantly correlated with louse counts in year 3 (r=0.36, p<0.05), but not in year 2 (r=0.25, p>0.05) or year 1 (r=0.04, p>0.05). Louse counts in the 3 years were significantly correlated with anti-B. ovis antibody concentration (r=0.60, 0.48, 0.36), but not with levels of either anti-B. ovis or total serum IgE. These results suggest that sheep with greater resistance to gastrointestinal parasites also tend to be less susceptible to lice. Whether this is due to interaction of the effects of the parasites or to correlation in underlying resistance mechanisms requires clarification.

Animals↗
PubMed2002

Sensitivity of two-stage sampling to detect sheep biting lice (Bovicola ovis) in infested flocks.

The sampling distribution of Bovicola ovis (Schrank) on sheep was examined in two flocks, one with a light and one with a heavy infestation of lice. The derived distributions were used to calculate the sensitivity of detecting lice on individual sheep and in flocks by fleece parting regimes that varied in number of parts per animal and number of sheep per flock, different scenarios of flock sizes, proportion infested and louse density were examined. Lice were aggregated among fleece partings in the heavily infested flock and described by a negative binomial distribution with k values between 0.3 and 1.92. The distribution was indistinguishable from Poisson in the lightly infested flock. The assumed distribution had little effect on sensitivity, except when only one fleece part per animal was examined. On individual sheep where louse density was 0.5 per 10 cm part or greater, there were only marginal gains from inspecting more than 10 parts per animal. Increasing the number of sheep inspected always increased sensitivity more than increasing number of parts per sheep by an equivalent amount. This advantage was greatest in situations where a low proportion of sheep in the flock were infested with a high density of lice, and less where a low proportion of sheep were infested with a low density of lice, or a high proportion of sheep were infested with a high density of lice.

Animals↗
PubMed2001

Survival away from sheep and alternative methods of transmission of sheep lice (Bovicola ovis).

Transmission of sheep lice is thought to occur mainly by sheep to sheep contact although the possibility of other sources of infestation is often suggested. This study investigated the period of survival of Bovicola ovis after removal from sheep under varying conditions and assessed the likelihood of new infestations arising from contaminated facilities, wool caught on fences and shearers' footwear. In laboratory studies with lice held away from sheep at 4, 20, 25 and 36.5 degrees C, adults and nymphs survived longest at 25 degrees C (LT90 of 11.7 and 24.1 days for adults and large nymphs, respectively). Nymphs survived longer than adults and lice provided with raw wool survived longer than lice provided with wool that had been degreased. Nymphal lice survived for up to 29 days on unscoured wool at 36.5 degrees C, but the LT50 was less than 9 days in most experiments. In shearing sheds in winter and early spring lice survived for up to 14 and 16 days, respectively. These periods of survival are considerably longer than previously indicated for B. ovis. Most lice dropped out of wool staples attached to a fence within 1 h and only two of a total of 225 lice were still present after 24 h, suggesting that sheep are unlikely to become infested from wool caught on fences. Adult and nymphal lice readily transferred to shearers' moccasins and survived there for up to 10 days, indicating that transmission of lice on the footwear of shearers or other sheep handlers may be a cause of new infestations. Microwaving each moccasin for 5 min killed all lice and may provide a simple method of reducing the likelihood of transmission of B. ovis between properties.

Animal Husbandry↗
PubMed2001

Modeling of cylindrically tapered cantilevers for transverse dynamic force microscopy (TDFM).

In transverse dynamic force microscopy a cylindrically tapered cantilever is mounted perpendicularly to the sample surface and set into transversal oscillation. The dynamics of the cantilever has been studied using the continuum mechanical model with discrete element analysis. A viscoelastic model has been used to describe the tip-sample interaction. In this way an in-phase and an out-of-phase component of the force has been extracted from the experimental data. Two different techniques, involving two experimental setups and two corresponding data analysis routines, have been developed to calculate the two components of the force at different tip-sample separations. In one case the change in resonant frequency and corresponding oscillation amplitude is measured whereas in the second case the usual way of recording amplitude and phase signal at a fixed driving frequency is applied. The results from these two methods are shown to be completely consistent and produce almost identical force curves.

Journal Article↗
PubMed2000

Aggressive aneurysmal bone cyst of the proximal humerus. A case report.

The case of an 11-year-old girl with a rapidly expanding, massive lesion in the right proximal humerus is reported. After biopsy, surgical treatment of the aneurysmal bone cyst consisted of aggressive intralesional resection with autogenous tibial strut grafting for reconstruction. After followup of 17 years with no recurrence of disease, there is excellent graft incorporation and remodeling and excellent function of the shoulder.

Biopsy↗
PubMed1999

Spatial distribution and spread of sheep biting lice, Bovicola ovis, from point infestations.

The spatial distribution of chewing lice (Bovicola ovis) on their hosts was examined in Polypay and Columbia ewes initially artificially infested on the midside or the neck. Densities of lice were determined at 69 body sites in eight body regions at approximately monthly intervals for 2 years. In the second year, half of the ewes were mated and lice were counted at 26 body sites on the resulting lambs. Polypay ewes had higher densities of lice than Columbias at most inspections but there was little effect of infestation point or mating on either numbers or the distribution of lice. During periods of high louse numbers densities were generally greatest on the sides or the back. Densities on the head were also high at times and peaked later than overall louse densities. Shearing markedly reduced density but increased the proportion of lice found on the neck, belly and lowleg sites. The distribution of lice on the lambs was similar to that on the ewes except that fewer lice were found on the head. Comparisons of lice per part with the numbers of lice extracted from clipped patches indicated that a sheep with wool bearing area of 1 m2 and a mean count of one louse per 10 cm fleece parting carried approximately 2000 lice. At most times of the year inspections for sheep lice should be concentrated on the sides and back, but in recently shorn sheep greater attention should be paid to the lower neck and ventral regions. Implications of the observed distributions of lice for the efficacy of chemical treatments are discussed.

Abdomen↗
PubMed1999

Do sheep regulate the size of their mallophagan louse populations?

Alternatives to chemicals for controlling parasites are required to minimise problems from resistance, residues in animal products and occupational exposure. Utilisation of host response to parasites through selection of resistant types or vaccination is an appealing option. To date most studies have been with haematophagous or invasive parasites which directly contact elements of the host immune system. Sheep lice (Bovicola ovis) feed superficially on the skin of sheep ingesting lipid, scurf, bacteria and loose stratum corneum squames. Evidence is presented that despite their surface feeding habit Bovicola ovis stimulate an immune response in sheep and that this response may play a part in regulating the size of louse populations.

Animals↗
PubMed1998

Seasonal dynamics and variation among sheep in densities of the sheep biting louse, Bovicola ovis.

Cyclic patterns and variations among sheep in numbers of Bovicola ovis are described in Polypay and Columbia ewes that were initially infested with equal numbers of lice and penned indoors continuously for 2 years. Bovicola ovis populations were censused at 3-4-week intervals at 69 body sites on each animal. In the second year of the study, the ewes were reinfested and half were mated. Louse populations were monitored on the resulting lambs from birth until 25 weeks of age. Strong seasonal cycles in louse numbers were observed on the ewes, with peaks in spring and troughs in summer. These cycles occurred in the absence of shearing, direct solar radiation or rainfall. Populations began to decline when daily mean and maximum temperatures were 11.5 degrees C and 15 degrees C, respectively, well below temperatures thought to cause warm season decline. Louse densities on Polypay ewes were approximately 10 times higher than on Columbias at most inspections. There were also large differences among sheep within breeds and sheep counts were highly correlated among dates, both within and between years. One third of the ewes failed to become infested despite having lice applied on five separate occasions and being penned together with other infested sheep. Pregnancy and lactation did not significantly affect louse numbers on the ewes. There was a significant negative correlation between louse counts and weight gains in the lambs, and lamb counts were significantly correlated with those of their dams up until, but not after, weaning. It is suggested that sheep may exert regulatory influences on lice which contribute to cycles in B. ovis populations.

Animals↗
PubMed1998

Pruritus and dermal response to insect antigens in sheep infested with Bovicola ovis.

This study examined the relationships among louse density, pruritus and dermal response to insect antigens in sheep infested with Bovicola ovis. Polypay and Columbia ewes were allocated to two groups, infested and naive, and louse densities and pruritus were monitored for 15 months. Ten months after the initial infestation, all sheep were tested for hypersensitivity on the midside and ears by intradermal injection of soluble extracts of B. ovis, Stomoxys calcitrans and Musca autumnalis. The areas of skin reactions were measured at 20 min, 1, 3 and 24 h after injection and skin thickness was measured at 24 h. Louse densities on Polypays were approximately 10 times greater than on Columbias, and pruritus was correlated with louse numbers at most inspections. Most pruritic behaviour was directed to the sides of infested sheep. Wheal and flare reactions developed rapidly to all extracts in both infested and naive ewes. Reactions to louse extract were larger in infested than naive sheep at all four times after injection. In the infested Polypays, reactions to louse extract were greater than to the fly extracts, but in naive sheep there was little difference among extracts. Reactions in naive Columbias were larger than in naive Polypays at 20 min, 1 and 3 h, but had almost completely abated in both groups at 24 h. Reactions in infested Columbias were greater than in infested Polypays at 20 min, but at 24 h reactions in the Polypays were larger. Louse numbers and pruritus were correlated with wheal areas and skin thickness at 24 h, but there was little relationship with the size of reactions at earlier times. These findings are consistent with the development of a hypersensitive response to B. ovis and suggest that dermal reactions to lice may influence sheep susceptibility.

Animals↗
PubMed1998

Serum and skin surface antibodies and their associations with sheep biting lice, Bovicola ovis, on experimentally infested sheep.

The sheep biting louse (Bovicola ovis) feeds superficially on the skin of sheep but appears to stimulate an immune response. In this study we examined the association between louse infestation and serum and skin surface antibodies. Louse numbers were monitored on experimentally infested Polypay and Columbia ewes for two years and on their lambs in the second year. Serum and skin wash samples were tested for antibodies to soluble extracts of B. ovis, Stomoxys calcitrans and Musca autumnalis by enzyme linked immunosorbent assay (ELISA). In addition, the effects of skin wash extracts on B. ovis were examined in vitro. The titre of anti-B. ovis antibodies in the serum did not differ significantly between infested and naive ewes. However, there was an increase in serum antibody titre which coincided with periods of high louse density in ewes with high louse counts. Infested lambs had higher serum antibody levels than naive lambs. Substantial cross reactivity was evident among extracts of the different insects. Densities of lice on the ewes during population decline were negatively related to the titre of skin surface antibodies. Skin washings collected from sheep during B. ovis population decline reduced the number of louse progeny when incorporated into louse diet. These results indicate that B. ovis stimulates an immune response in sheep and suggest that compounds on the skin surface may play a role in the regulation of louse populations.

Animals↗
PubMed1998

Médecine à la Molière.

Of Moliere's thirty six plays, seven deal, to a greater or lesser extent, with medicine; the medicine as practiced in Paris during the reign of Louis XIV. In these days, Moliere satirises the recalcitrant conservatism of the Paris medical faculty. It is, however, an informed satirisation. This paper explores Moliere's motives and attempts to place Moliere's medical plays against a broad canvas of his other works. The ultimate purpose is to assess to what extent Moliere's philosophical persuasions and how he balanced them against the needs of contemporary, commercial theatre.

Drama↗
PubMed1994

Controlled release insecticide devices for protection of sheep against head strike caused by Lucilia cuprina.

The effectiveness of polymer matrix tags containing (w/w) 8.5% cypermethrin, 7.5% flucythrinate, 13.7% tetrachlorvinphos or 20.0% diazinon in protecting sheep against head strike by the sheep blowfly (Lucilia cuprina Wiedemann) was investigated in larval implant, fly cage and field studies. Tags impregnated with cypermethrin reduced the total number of egg masses deposited on the heads of sheep in fly cage studies over a 6 week period by 73.3% compared with no treatment. Tags impregnated with flucythrinate reduced the number of egg masses by 25.3% over 21 weeks but there were no significant differences (P < 0.05) between treated and untreated sheep at individual exposures. Egg masses were found on the majority of tagged sheep and no protection was provided against implants with first instar L. cuprina larvae by either cypermethrin or flucythrinate tags. Tags impregnated with diazinon gave longer protection than treatment with a liquid formulation containing 400 ppm diazinon in larval implant, fly cage and field studies. Over a 12 week period in field studies, 6.6% of rams treated with diazinon tags became struck compared with 30% treated by diazinon jetting, 35.7% treated with plastic tags not impregnated with insecticide and 24.2% of untreated rams. When the rams were exposed to high populations of L. cuprina in an exposure house from 13 to 18 weeks after treatment, 3.3% of rams treated with diazinon tags, 57.1% treated by diazinon jetting, 43.8% treated with plastic tags and 23.5% of untreated rams became struck. Most strikes in the diazinon tagged sheep occurred at sites which were not contacted by the tags. Tags impregnated with tetrachlorvinphos reduced the number of strikes in comparison with no treatment in larval implant and fly cage studies but the results were inconsistent and not as good as those from diazinon tags. It is concluded that well designed controlled release devices that reliably contact the wool on the heads of sheep at sites of flystrike risk and which are able to withstand damage from rams fighting may be able to give prolonged protection against head strike.

Administration, Topical↗
PubMed1994

Methicillin-resistant Staphylococcus epidermidis in infection of hip arthroplasties.

We investigated the incidence of cephalosporin-resistant bacteria in infected hip arthroplasties. Of 740 patients having hip replacement or related procedures performed over three years, 30 had positive bacteriological cultures from tissue removed at the time of surgery. In 18 of the 30 cultures Staphylococcus epidermidis was grown and 12 of these were methicillin-resistant. A prospective study of skin swabs taken from 100 consecutive patients at the time of admission for THR showed methicillin-resistant Staphylococcus epidermidis in 25. This cephalosporin-resistant organism was shown to be the commonest proven cause of infection, and its presence as a skin commensal raises important questions about current antibiotic prophylaxis for joint replacement.

Combined Modality Therapy↗
PubMed1993

Resistance to synthetic pyrethroids in South Australian populations of sheep lice (Bovicola ovis).

Lice were collected from 71 flocks detected as infested at market inspection in 1990 and 1991, from 16 flocks where resistance was suspected and from 31 flocks from Kangaroo Island. Susceptibility to cypermethrin was measured by a treated surface technique and survival of lice at 5 ppm or greater was taken as an indication of resistance. The prevalence of resistance was 34% in louse populations from the market inspection sample, 50% in flocks in which resistance was suspected and 68% in flocks from Kangaroo Island. Most resistance factors were in the range 1 to 20 although one louse population with a resistance factor of 91 was found on Kangaroo Island.

Animals↗
PubMed1990

Evaluation of ear tags impregnated with cypermethrin for the control of sheep body lice (Damalinia ovis).

The application of polymer matrix ear tags impregnated with 8.5% w/w cypermethrin to 6 wethers following shearing reduced lice to non-detectable levels on 4 of them at 29 weeks after tagging. At the conclusion of the study at 45 weeks the mean count of lice on tagged wethers was 3 per sheep compared to 158 on untreated wethers. In a second experiment, 6 non-infected sheep were treated at shearing with cypermethrin tags, 6 with 25 g/l cypermethrin backline formulation, 6 with tags plus backline and 6 were left untreated. Each group was exposed to 6 sheep with moderate to heavy infestations of lice. Compared to controls, all treatments delayed infestation, but cypermethrin tags gave no longer protection than backline treatment. All sheep were infested by 17 weeks after commencement of the study. At 45 weeks mean counts of lice were 38, 27, 20 and 74 respectively for sheep treated with tags, backline formulation, backline plus tags and untreated. Possible reasons for the better effect observed from applying tags to infested sheep than to sheep which were not infected at application but which were subsequently exposed to infested sheep are discussed.

Analysis of Variance↗