War zone stress without direct combat: the Australian naval experience of the Gulf War

This study examines psychological stressors reported by Australian Navy Gulf War veterans in relation to the 1991 Gulf War and other military service. Using a 44-item questionnaire, veterans reported few direct-combat encounters during the Gulf War; however, they reported many other stressful experiences, including fear of death and perceived threat of attack, more frequently in relation to the Gulf War than other military service. Reporting of stressful experiences was associated with younger age, lower rank, and deployment at the height of the conflict. These experiences may partly explain increased rates of psychological disorders previously demonstrated in this Navy veteran population. Findings highlight the importance of documenting war experiences in close proximity to deployment, and developing war exposure instruments which include naval activities and which reflect stressors other than those related to direct combat.

The health of Australian veterans of the 1991 Gulf War: factor analysis of self-reported symptoms

BACKGROUND

A recent report showed that Australian veterans of the 1991 Gulf War displayed a greater prevalence of a multitude of self-reported symptoms than a randomly sampled comparison group of military personnel who were eligible for deployment but were not deployed to the Gulf.

AIMS

To investigate whether the pattern, rather than frequency, of symptom reporting in these Australian Gulf War veterans differed from that of the comparison group personnel.

METHODS

Factor analysis was used to determine whether the co-occurrence of 62 symptoms in 1322 male Gulf War veterans can be explained by a number of underlying dimensions, called factors. The methodology was also applied to 1459 male comparison group subjects and the factor solutions of the two groups were compared.

RESULTS

For the Gulf War veterans, a three factor solution displayed replicability and construct validity. The three factors were labelled as psycho-physiological distress, somatic distress, and arthro-neuromuscular distress, and were broadly similar to those described in previous studies of Gulf War veterans. A concordant three factor solution was also found for the comparison group subjects, with strong convergence of the factor loadings and factor scores across the two groups being displayed.

CONCLUSION

Results did not display evidence of a unique pattern of self-reported symptoms among Gulf War veterans. Results also indicated that the differences between the groups lie in the degrees of expression of the three underlying factors, consistent with the well documented evidence of increased self-reported symptom prevalence in Gulf War veterans.

Symptoms and medical conditions in Australian veterans of the 1991 Gulf War: relation to immunisations and other Gulf War exposures

AIMS

To investigate whether Australian Gulf War veterans have a higher than expected prevalence of recent symptoms and medical conditions that were first diagnosed in the period following the 1991 Gulf War; and if so, whether these effects were associated with exposures and experiences that occurred in the Gulf War.

METHODS

Cross-sectional study of 1456 Australian Gulf War veterans and a comparison group who were in operational units at the time of the Gulf War, but were not deployed to that conflict (n = 1588). A postal questionnaire was administered and the likelihood of the diagnosis of self-reported medical conditions was assessed and rated by a medical practitioner.

RESULTS

Gulf War veterans had a higher prevalence of all self-reported health symptoms than the comparison group, and more of the Gulf War veterans had severe symptoms. Increased symptom reporting was associated with several exposures, including having more than 10 immunisations, pyridostigmine bromide tablets, anti-biological warfare tablets, pesticides, insect repellents, reportedly being in a chemical weapons area, and stressful military service experiences in a strong dose-response relation. Gulf War veterans reported psychological (particularly post-traumatic stress disorder), skin, eye, and sinus conditions first diagnosed in 1991 or later more commonly than the comparison group. Over 90% of medical conditions reported by both study groups were rated by a medical practitioner as having a high likelihood of diagnosis.

CONCLUSION

More than 10 years after the 1991 Gulf War, Australian veterans self-report all symptoms and some medical conditions more commonly than the comparison group. Further analysis of the severity of symptoms and likelihood of the diagnosis of medical conditions suggested that these findings are not due to over-reporting or to participation bias.

Impact of eprinomectin on grazing behaviour and performance in dairy cattle with sub-clinical gastrointestinal nematode infections under continuous stocking management

Forty spring-calving cows and heifers (20 of each) were allowed to acquire infection with gastrointestinal (GI) nematodes naturally during grazing. The control group (10 cows and 10 heifers) were compared with 20 similar animals treated with eprinomectin in order to evaluate the effect of GI nematodes on grazing behaviour, milk production, body condition score and live weight. The animals were paired according to parity and milk yield during the week prior to treatment, then within replicate pair randomly allocated to a different treatment group. The grazing area was sub-divided into 20 replicated paddocks of equivalent size and topography. Grazing pairs of either control or treated animals were randomly assigned to each paddock over the duration of the study (one pair per paddock). Grazing behaviour was recorded for both groups over a 10-day period commencing 4 days after treatment with eprinomectin. Milk yield was recorded daily and milk quality was recorded weekly. Live weight and body condition score were recorded on the day of allocation, the day of initial treatment and thereafter at weekly intervals until the end of the 4-week trial. Faecal samples were collected from each animal prior to, and after, allocation and submitted for counts of nematode eggs. Additional faecal samples were taken at the end of the study for culture and nematode identification. Individual faecal samples were also analysed for residual digestibility. Pasture samples for nematode larval counts were taken at the same time as faecal sampling. The parasitological results showed low levels of faecal nematode egg output throughout the study, with the heifers having higher counts than the cows. Faecal culture yielded species of Ostertagia, Cooperia, and Trichostrongylus. Pasture larval levels were very low throughout with no value exceeding 68 larvae/kg dry matter (DM) of herbage. There were significant (P < 0.05) effects of treatment on grazing time, eating time, total bites, total grazing jaw movements (TGJM), idling time and mean meal duration. Treated cows and heifers grazed for 47 and 50 min longer per day, respectively, than controls (P = 0.016). Mean meal duration was extended as a result of anthelmintic treatment by 11 and 38 min, in cows and heifers, respectively (P = 0.012). There were no significant (P > 0.05) treatment effects on ruminating time or residual faecal digestibility, but idling time was significantly reduced in both treated cows and heifers, by 50 and 110 min, respectively (P = 0.010). In the treated cattle, there was an increase in solids-corrected milk yield compared with the control cattle, which was significant (P < 0.05) in weeks 2 and 3 after treatment. The response was particularly marked in heifers, where the difference in yield between treated and controls was up to 2.35 kg/day. The differences in live weight gain and condition score over 28 days post-treatment were significant (P < 0.05) in both cows and heifers, in favour of the treated animals.

Psychological health of Australian veterans of the 1991 Gulf War: an assessment using the SF-12, GHQ-12 and PCL-S

BACKGROUND

Elevated rates of psychological morbidity and symptomatology have been widely reported in 1991 Gulf War veterans. The present study used brief self-report instruments to compare the psychological health of Australian Gulf War veterans with that of a randomly sampled military comparison group.

METHOD

The 12-item Short Form Health Survey (SF-12), 12-item General Health Questionnaire (GHQ-12), Posttraumatic Stress Disorder Checklist--Specific (PCL-S) and Military Service Experience (MSE) questionnaire were administered to 1424 male Australian Gulf War veterans and 1548 male Australian Defence Force members who were operational at the time of the Gulf War conflict, but were not deployed there.

RESULTS

The Gulf War veterans exhibited poorer psychological health, as measured by the above three instruments, than the comparison group members. For Gulf War veterans, the number of stressful experiences, as measured by the MSE questionnaire, was correlated with scores on the three instruments. SF-12 mental health component summary scores and PCL-S caseness, but not GHQ-12 caseness, differed significantly between Gulf War veterans and comparison group members who had been on at least one active deployment.

CONCLUSIONS

More than a decade after the 1991 Gulf War, Australian Gulf War veterans are exhibiting higher levels of current (past month) psychological ill-health, as measured using the GHQ-12 and PCL-S, as well as lower mental health status, as measured by the SF-12, than the comparison group. Although not a replacement for formal psychiatric diagnosis, instruments such as those above may aid in the assessment of veterans' psychological health.

Respiratory health status of Australian veterans of the 1991 Gulf War and the effects of exposure to oil fire smoke and dust storms

BACKGROUND

Since the 1991 Gulf War concerns have been raised about the effects on veterans' health of exposures to Kuwaiti oil fire smoke and to dust storms.

METHODS

A cross sectional study compared 1456 Australian Gulf War veterans with a randomly sampled military comparison group (n = 1588). A postal questionnaire asked about respiratory conditions, exposures, medications, tobacco use, demographic characteristics, and military service details. During a medical assessment, spirometric tests and a physical examination were performed and a respiratory questionnaire was administered.

RESULTS

The response rate for the Gulf War veteran group was 80.5% and for the comparison group 56.8%. Australian Gulf War veterans had a higher than expected prevalence of respiratory symptoms and respiratory conditions suggesting asthma (OR 1.4; 95% CI 1.1 to 1.9) and bronchitis first diagnosed since the Gulf War (OR 1.9; 95% CI 1.2 to 3.1) but did not have poorer lung function or more ventilatory abnormalities than the comparison group. Veterans who reported exposure to oil fire smoke had slightly poorer forced vital capacity (difference between means -0.10 l; 95% CI -0.18 to -0.03) and those exposed to dust storms had a slightly better peak expiratory flow rate (difference between means 12.0 l/min; 95% CI 0.6 to 23.4) than veterans who did not report exposure. Veterans who were in the Gulf at or after the start of the oil fires had more respiratory conditions suggesting asthma (OR 1.7; 95% CI 1.0 to 2.9) than those who completed their deployment before this time.

CONCLUSIONS

Increased self-reporting of respiratory symptoms, asthma, and bronchitis by veterans was not reflected in poorer lung function. The findings do not suggest major long term sequelae of exposure to oil fire smoke or dust storms.

War-related psychological stressors and risk of psychological disorders in Australian veterans of the 1991 Gulf War

BACKGROUND

Questions remain about the long-term health impacts of the 1991 Gulf War on its veterans.

AIMS

To measure psychological disorders in Australian Gulf War veterans and a military comparison group and to explore any association with exposure to Gulf War-related psychological stressors.

METHOD

Prevalences of DSM-IV psychological disorders were measured using the Composite International Diagnostic Interview. Gulf War-related psychological stressors were measured using a service experience questionnaire.

RESULTS

A total of 31% of male Gulf War veterans and 21% of the comparison group met criteria for a DSM-IV disorder first present in the post-Gulf War period. The veterans were at greater risk of developing post-Gulf War anxiety disorders including post-traumatic stress disorder, affective disorders and substance use disorders. The prevalence of such disorders remained elevated a decade after deployment. The findings can be explained partly as a 'war-deployment effect'. There was a strong dose-response relationship between psychological disorders and number of reported Gulf War-related psychological stressors.

CONCLUSIONS

Service in the 1991 Gulf War is associated with increased risk of psychological disorders and these are related to stressful experiences.

How well do doctors know their patients with severe asthma?

BACKGROUND

Rates of asthma mortality have fallen in Australia since the commencement of the National Asthma Campaign and promotion of the Australian asthma management plan. New strategies are now needed to further reduce mortality.

AIM

To examine agreement about key features between asthma patients and their general practitioners (GPs).

METHODS

We interviewed: (i) the next of kin of 56 asthma deaths, (ii) 91 asthma patients presenting to emergency departments with acute severe asthma and (iii) 147 of their GPs.

RESULTS

Agreement was substantial for usage of oral symptomatic medication, but poor for inhaled symptomatic and preventive medications. There was moderate agreement regarding hospital admissions within the last 12 months among the cases, but little about other markers of severity. There was moderate agreement where the presenting or fatal attack was triggered by an upper respiratory-tract infection or aspirin. The next of kin and GPs agreed about family problems, but not about other psychosocial issues. They also agreed about which cases had been given action plans or verbal instructions, but few other aspects of asthma management. There was also moderate agreement regarding the use of peak flow meters by the controls.

CONCLUSIONS

Doctors often have relatively poor insights into self-management practices, social background or trigger factors, even in high-risk patients. This should be considered when planning future campaigns to improve asthma management and further reduce mortality.

Transmission electron microscope study of the ultrastructural changes induced in the tegument and gut of Fasciola hepatica following in vivo drug treatment with clorsulon

Using transmission electron microscopy (TEM), both the tegument and gut of Fasciola hepatica were examined in an effort to identify and characterise the ultrastructural changes induced following treatment with the flukicidal drug clorsulon. Male Sprague-Dawley rats infected with F. hepatica were dosed orally at 8-8.5 weeks post-infection with clorsulon at a concentration of 12.5 mg/kg body weight. After 24, 48 and 72 h, rats were sacrificed by cervical dislocation and mature flukes recovered from the bile ducts. After 24 h treatment in vivo, disruption of the tegumental syncytium was concentrated at the apex of the syncytium where a dark band consisting of numerous secretory bodies was present. Some blebbing of the apex had also occurred, "open" bodies were present in this region and the mitochondria were slightly swollen. In the cell bodies, swelling of the mitochondria and their cristae had also occurred and the Golgi complexes appeared to be smaller than normal. The disruption seen after 48 h treatment in vivo was similar but more severe: the frequency of blebbing had increased, as had the number of "open" bodies and the swelling of the mitochondria. Vacuoles had begun to appear in the syncytium-both autophagic and electron-lucent-and swelling of the mucopolysaccharide masses around the basal infolds had occurred. Lipid droplets were observed occasionally. In the cell bodies, autophagic vacuoles had begun to appear and swelling of the mitochondria had increased in severity. After 72 h treatment in vivo, more severe disruption was seen in the tegumental syncytium in which widespread swelling and blebbing of the apex was apparent. The basal infolds had become very badly swollen in a number of specimens and damage to the spines was evident. The mitochondria remained swollen, as did the mucopolysaccharide masses around the basal infolds. Lipid droplets were more frequently observed in the syncytium. In the tegumental cells, swelling of the mitochondria was greater and an increase in the number of autophagic vacuoles was apparent. The gut showed signs of disruption after 24 h treatment in vivo, in that the surface lamellae were disrupted and a build-up of autophagic vacuoles at the apex of the cells had taken place. Swelling of the mitochondria and the cisternae of granular endoplasmic reticulum (gER) was evident. There was a decrease in the number of secretory bodies. After 48 h treatment in vivo, the number of autophagic vacuoles in the gastrodermal cells had increased, the mitochondria and gER remained swollen and the disruption seen to the lamellae was still evident. In the 72 h-treated specimens, the disruption seen in the gastrodermal cells had increased significantly, with severe vacuolation of the apical cytoplasm. An increase in the number of autophagic vacuoles was evident, the mitochondria and the gER remained swollen and lipid droplets were present in the cells.

Fasciola hepatica: tegumental surface alterations following treatment in vivo and in vitro with nitroxynil (Trodax)

Male Sprague-Dawley rats were dosed orally with nitroxynil at a concentration of 40 mg/kg and adult Fasciola hepatica recovered after 24 h, 48 h and 72 h. Surface changes to the flukes were monitored by means of SEM. After the 24 h treatment, extensive swelling and blebbing of the tegument was observed on both surfaces, although the dorsal anterior region was more severely affected than either the posterior dorsal region or entire ventral surface. At high magnification, microvillus-like projections were evident, giving the surface a roughened appearance. After 48 h, the changes evident at 24 h had become more severe and some tegumental loss had occurred in the oral region of the fluke. Surface disruption was particularly evident along the lateral margins of the fluke in this region. In some specimens a single large swelling was present in the dorsal midbody region. The swelling was a more typical feature of flukes recovered. After 72 h, tegumental loss was more widespread, occurring over the oral cone and anterior midbody on the dorsal surface. Overall the dorsal surface was consistently more severely affected than the ventral surface, and the anterior region of the fluke was more disrupted than the posterior region. After 24 h in vitro incubation, the oral cone and midbody exhibited considerable spine loss and swelling. Overall, the dorsal surface was more disrupted than the ventral surface and the anterior region of the fluke was more disrupted than the posterior region. Regional differences in the response of the fluke to nitroxynil will be compared to previously published data with other fasciolicides. The results indicate that the tegument is an important target for nitroxynil action. Disruption of this, the fluke's main line of defence, would allow the drug access to other internal tissues, leading to more widespread damage.

Fasciola hepatica: effects of the fasciolicide clorsulon in vitro and in vivo on the tegumental surface, and a comparison of the effects on young- and old-mature flukes

The ultrastructural changes in Fasciola hepatica induced by the fasciolicide clorsulon were assessed using scanning electron microscopy. At 8 and 44 weeks post-infection, male Sprague-Dawley rats infected with F. hepaticawere dosed orally with clorsulon at a concentration of 12.5 mg/kg and mature flukes recovered from the bile duct after 24 h, 48 h, and 72 h in both experiments. An in vitro incubation was also set up using mature fluke (8 weeks old) incubated with clorsulon for 24 h at a concentration of 10 microg/ml. After 24 h in vivo, the young-mature flukes (8 weeks old) showed significant disruption to the tegumental surface, particularly in the anterior mid-body region, where a distinct band of swelling and blebbing was evident. The band began just behind the ventral sucker and ran posteriorly along both margins. The apical cone region of the fluke was characterised by swelling and blebbing of the surface between the spines. Similar changes were evident after 48 h in vivo, but the disruption was more severe and the mid-body band had spread posteriorly. In approximately half of the specimens recovered after 72 h in vivo, widespread disruption had occurred, with sloughing of the apical membrane or the entire syncytium, over almost all of the oral cone and anterior mid-body. For all time periods, the anterior half of the fluke was more severely affected than the posterior half. No differences were seen between the dorsal and ventral surfaces. Old-mature flukes (44 weeks old) showed regionally similar, but more severe and widespread disruption than that seen in the young-mature flukes. The onset of surface changes occurred more quickly in old-mature flukes as well. Eight-week-old flukes which had been incubated for 24 h in vitro showed surprisingly little disruption, but this may be due to the method by which the drug is taken up by the fluke.

Residential characteristics predict changes in Der p 1, Fel d 1 and ergosterol but not fungi over time

BACKGROUND

Allergen and fungal exposures are important risk factors for asthma. We conducted a longitudinal analysis of allergen levels in Melbourne homes between 1996 and 1998 to examine the effects of changing residential characteristics on allergen and fungal levels. We also examined the changes in levels of indoor allergens.

METHODS

The subjects were participants in the European Community Respiratory Health Survey (ECRHS) in Melbourne. In 1996, 485 subjects participated in a follow-up study, which involved both home and laboratory visits. Dust and air samples were collected from participants' bedrooms and a validated residential questionnaire was administered. In 1998, 360 participants underwent further follow-up. House dust mite (Der p 1) and cat allergens (Fel d 1) and ergosterol were measured in dust.

RESULTS

We observed moderate within home correlations between 1996 and 1998 in floor Der p 1 (intraclass correlation ICC=0.48), bed Der p 1 (ICC=0.61), Fel d 1 (kappa=0.53) and ergosterol (ICC=0.28) levels. We found that the floor Der p 1 levels decreased from 1996 to 1998 in the homes of participants who moved to an attached home, moved their bedrooms to the first floor, removed fitted carpet or central heating. Replacing or vacuuming the mattress more than twice per year reduced levels of Der p 1 in the bed. Ergosterol levels were reduced by removing visible mould and fitted carpet.

CONCLUSIONS

These findings provide evidence to support current advice with regard to allergen avoidance in patients with dust mite and fungal allergies.

Case-control studies of sporadic cryptosporidiosis in Melbourne and Adelaide, Australia

Few studies have assessed risk factors for sporadic cryptosporidiosis in industrialized countries, even though it may be numerically more common than outbreaks of disease. We carried out case-control studies assessing risk factors for sporadic disease in Melbourne and Adelaide, which have water supplies from different ends of the raw water spectrum. In addition to examining drinking water, we assessed several other exposures. 201 cases and 795 controls were recruited for Melbourne and 134 cases and 536 controls were recruited for Adelaide. Risk factors were similar for the two cities, with swimming in public pools and contact with a person with diarrhoea being most important. The consumption of plain tap water was not found to be associated with disease. This study emphasizes the need for regular public health messages to the public and swimming pool managers in an attempt to prevent sporadic cryptosporidiosis, as well as outbreaks of disease.

Sub-clinical parasitism in spring-born, beef suckler calves: epidemiology and impact on growth performance during the first grazing season

Sub-clinical parasitism in spring-born single suckled beef calves was investigated from the middle of their first grazing season until weaning or housing later the same year. The study was conducted on four beef suckler herds in southern England over a 3-year period and involved a total of 334 spring-born beef suckler calves and their dams. The animals were grazed extensively on pastures naturally infected with nematode larvae. At the start of each period of observation, faecal samples were taken from calves and cows and subjected to routine worm egg counts; calves were re-sampled at the end of the grazing season. In July in each year and at each location the calves were ranked by initial weight within sex, paired according to rank and randomly allocated to either an untreated control group or a group in which the calves were each treated with an ivermectin sustained-release (SR) bolus. The calves in both trial groups, and their dams, were grazed together until weaning or housing. The calves were weighed at the initial allocation and at the end of the study. The adult cows were not treated with any anthelmintic during the study. The faecal nematode egg counts (FECs) conducted in July showed that the suckler cows were excreting worm eggs at low concentrations: range 0-100 eggs per gram (epg), with one individual count of 500epg, 88% of the cows sampled had counts of <50epg. Similarly, the counts from the calf samples were fairly low in July: range 0-250epg, 73% of the calves sampled had counts of <50epg. By the end of the grazing season, the faecal samples from the untreated control calves showed higher values: range 0-650epg, with only 58% having an epg of <50. The average rate of daily liveweight gain in the untreated heifer calves was 0.79kg per day, the corresponding figure for the heifer calves treated with the ivermectin SR bolus in mid-summer was 0.88kg per day; the difference of 90g per day was significantly different (P=0.0118). The average rate of daily liveweight gain in the untreated bull calves was 0.91kg per day, the corresponding figure for the bull calves treated with the ivermectin SR bolus in mid-summer was 1.01kg per day; the difference was significantly different (P=0.0169).

Color and defective color vision as factors in the conspicuity of signs and signals

The conspicuity of road traffic signs and signals for a group of observers with the color vision defect of deuteranopia is compared with that for a control group of observers with normal color vision. Conspicuity was measured by the proportion of reports of target objects detected in 300-ms presentations of projected slides of road scenes. There were two instructions, one designed to measure attention conspicuity and the other, search conspicuity. The attention conspicuity of red, orange, and green color-coded traffic control devices was significantly less for deuteranopes than for the observers with normal color vision, but this was not true for yellow and blue color-coded signs. This result is consistent with our understanding of the color perceptions of deuteranopes. The reduction of conspicuity was not so great for the search conspicuity condition. We conclude that redundant color coding does contribute to the conspicuity of signs and signals and that deuteranopes--and probably those with other severe forms of defective color vision--have a significantly reduced ability to notice colored targets, such as road signs and signals, in complex visual environments. The actual and potential application of this work is in the design of signs so they are conspicuous, especially when the user group includes people with defective color vision.

A randomized, blinded, controlled trial investigating the gastrointestinal health effects of drinking water quality

A double-blinded, randomized, controlled trial was carried out in in Melbourne, Australia, to determine the contribution of drinking water to gastroenteritis. Melbourne is one of the few major cities in the world that draws drinking water from a protected forest catchment with minimal water treatment (chlorination only). Six hundred families were randomly allocated to receive either real or sham water treatment units (WTUs) installed in their kitchen. Real units were designed to remove viruses, bacteria, and protozoa. Study participants completed a weekly health diary reporting gastrointestinal symptoms during the 68-week observation period. There were 2,669 cases of highly credible gastroenteritis (HCG) during the study (0.80 cases/person/year). The ratio of HCG episode rates for the real WTU group compared to the sham WTU group was 0.99 (95% confidence interval, 0.85-1.15, p = 0.85). We collected 795 fecal specimens from participants with gastroenteritis, and pathogens were not more significantly common in the sham WTU group. We found no evidence of waterborne disease in Melbourne. The application of this methodology to other water supplies will provide a better understanding of the relationship between human health and water quality.

Assessing the risk of tuberculosis infection among healthcare workers: the Melbourne Mantoux Study. Melbourne Mantoux Study Group

OBJECTIVE

To determine the potential prevalence of nosocomial infection with Mycobacterium tuberculosis among hospital employees in teaching hospitals in Melbourne.

DESIGN

Cross-sectional survey of positive tuberculin skin test (Mantoux) responses among employees in 14 public hospitals in Melbourne, January 1996 to April 1999.

PARTICIPANTS

All consenting employees in participating hospitals (4,070 healthcare and 4,298 non-healthcare workers; participation rates, 13%-66%).

OUTCOME MEASURES

Prevalence of positive responses to tuberculin skin tests among healthcare and non-healthcare workers and association with employee and hospital characteristics.

RESULTS

Healthcare workers were significantly more likely to have a positive tuberculin response than non-healthcare workers (19.3% versus 13.7%; odds ratio, 1.5; 95% CI, 1.3-1.7; P<0.001). Multivariable analysis revealed that age, country of birth (high versus low tuberculosis [TB] prevalence), history of BCG (bacille Calmette-Guérin) vaccination, years since last BCG, occupation (healthcare versus non-healthcare worker) and years of hospital employment were all significantly associated with a positive response. Rates of positive responses among employees varied greatly between hospitals (6%-35%). These differences were not explained by employee characteristics, hospital TB patient load (number of admissions or bed-days) or percentage of hospital patients from countries with high TB prevalence. The hospital with the highest rate of positive responses was notable for its lack of negative-pressure isolation rooms for TB patients.

CONCLUSIONS

Positive tuberculin responses are relatively common among hospital employees in Melbourne, with rates varying between hospitals and being higher among healthcare than non-healthcare workers. Employee characteristics, such as age, country of birth and past BCG status, explain little of this variation. More emphasis on TB infection control measures and regular staff screening may be needed.

The relationships between patients' related variables in asthma: iplications for asthma management

OBJECTIVE

Understanding patients' personal characteristics is essential for better asthma management. This study assessed the relationships between patients' related variables in asthma and identified key associations relevant to asthma management.

METHODOLOGY

Subjects were recruited from the Alfred Hospital Asthma and Allergy Clinic (Melbourne, Victoria, Australia) and general practices. Their clinical and demographic characteristics, asthma knowledge, impact of asthma on their quality of life, their self-management skills and attitudes to asthma were assessed.

RESULTS

One hundred and sixty-nine subjects participated in the study. Fifty-seven per cent had one or more previous hospital admissions, 94% had either moderate or severe asthma, and 51% reported nocturnal symptoms in the last 6 weeks. Patients who spoke only English, had been admitted to an intensive care unit, had a peak flow meter, and an asthma action plan had significantly better asthma knowledge than those who did not. The impact of asthma was greatest in patients who had a peak flow meter, used oral steroids, had exercise limitation, and developed asthma between the ages of 31-45 years. Female patients had better self-management skills than males. Patients with asthma-related distress were more likely to use oral steroids or theophylline and to have a history of previous hospital admissions. Patient self-confidence was negatively correlated with age.

CONCLUSIONS

There are significant relationships between many of patients' variables related to asthma, including their personal clinical, demographic and psychological characteristics. The findings have implications for optimizing asthma management.

Methods used to maintain a high level of participant involvement in a clinical trial

OBJECTIVES

To describe the strategies adopted to maintain high level participation throughout a community based clinical trial, and the reasons given by participants for why they participated in the study.

DESIGN

Observational study.

SETTING

Community based clinical trial in Melbourne, Australia that ran for 68 weeks and involved 2811 community based individuals from 600 families. A high level of commitment was required of the families; each participant completed a Health Diary each week of the 68 week study, as well as answering numerous other questionnaires, and providing faecal and blood samples.

MAIN RESULTS

Only 41 of the 600 families withdrew from the study; the majority of these families withdrew because they sold their home and moved from the study area. The completion rate of Health Diaries averaged 90.7% over the 68 weeks of data collection. Of the 559 families who completed the study, 524 (93.7%) completed the Participation Questionnaire. The statement that received the highest rating for why families enrolled in the study was they thought the study was researching an important community issue. The statements that received the highest ratings for why families continued to participate in the study was the family being kept well informed about the study's progress and that the study was well run.

CONCLUSIONS

The low numbers of withdrawals and the high level of participation throughout the study suggests the strategies of (a) having a non-aggressive recruitment method, (b) maintaining regular contact with the participants and (c) ensuring participants were kept well informed of the study's progress and constantly encouraged to continue participation were successful. The results also suggest people involve themselves in research because they perceive it to be of value to the community, not simply for personal gain. They indicated that they maintained their participation because it was a well run study and they were kept well informed throughout the study.

Are asthma medications and management related to deaths from asthma?

There is controversy about the role of beta-agonists in asthma mortality, and the impact of asthma management plans remains unclear. We compared blood beta-agonist levels in patients dying from asthma with those in controls, and estimated the risks associated with specific classes of medication and patterns of management. We identified 89 asthma deaths and recruited 322 patients presenting to hospitals with acute asthma. A questionnaire was administered to the next of kin in 51 cases, and to 202 controls. Blood drawn from 35 cases and 229 controls was assayed for salbutamol. Smoking, drinking, and family problems were significantly more likely among the cases of asthma death than among the controls. The two groups were reasonably well matched with regard to markers of chronic asthma severity. Cases of asthma death were significantly less likely than controls to use a peak flow meter. Written action plans were associated with a 70% reduction in the risk of death. Use of nebulized bronchodilators or oral steroids was significantly more likely in cases of asthma death. Mean blood salbutamol concentrations were 2.5 times higher in cases of asthma. The use of oral steroids for an attack of asthma reduced the risk of death by 90%. More widespread adoption of written asthma management plans, with less reliance on beta-agonists and closer medical supervision, should reduce asthma mortality.

Patterns of parasitic nematode infection and immunity in dairy heifers treated with ivermectin in a sustained-release bolus formulation either at turnout or in the middle of the grazing season

Twenty-eight Holstein-Friesian heifers, born the previous year and weighing between 130 and 310 kg, were allocated to one of two treatment groups by restricted randomisation, based on their initial weight. The heifers in group 1 were each treated with ivermectin in a sustained-release bolus formulation at turnout in April, and those in group 2 were each given an ivermectin bolus on July 10, 84 days after turnout. On that day the mean geometric worm egg counts of groups 1 and 2 were 0.4/g and 38.8/g, respectively, and they both had a mean plasma pepsinogen concentration of 0.59 iu/litre; in group 1, two of 14 faecal samples were positive for Dictyocaulus viviparus larvae, and in group 2 all 13 samples were positive; in group 1 eight calves were positive and three inconclusive for the presence of antibodies to D viviparus, and in group 2 the corresponding figures were 10 positive and two inconclusive; the mean liveweights of groups 1 and 2 were 274.4 kg and 262.8 kg, respectively. By December 4,231 days after turnout, the corresponding results were: mean geometric worm egg counts of 2.2/g and 0.5/g; one of 13 and none of 14 faecal samples positive for D viviparus larvae; 12 positive and two inconclusive and none positive and 10 inconclusive for the presence of antibodies to D viviparus; 214 days after turnout their mean liveweights were 361.1 kg and 358.3 kg. Although the patterns of parasitic nematode infection were different in the two groups during the grazing season, by the time they were housed both groups had achieved similar liveweights and showed evidence of an immune response to both D viviparus and gastrointestinal nematodes.

The ixodid tick species attaching to domestic dogs and cats in Great Britain and Ireland

The species of ixodid ticks, attached to dogs and cats presented to veterinary practices in Great Britain and Ireland were identified. Most host animals carried only one tick species with Ixodes ricinus Linné (Acari: Ixodidae) being the most common, identified on 52% of animals, Ixodes hexagonus Leach (Acari: Ixodidae) the second most common (on 39%) and Ixodes canisuga Johnston (Acari: Ixodidae) the third most common (on 11%). A significantly higher proportion of dogs than cats carried I. ricinus, while I. hexagonus was more frequently carried by cats. One animal carried a single specimen of Haemaphysalis punctata Canestrini & Fanzago (Acari: Ixodidae), one carried a Dermacentor reticulatus Fabricius (Acari: Ixodidae) but none carried Rhipicephalus sanguineus Latreille (Acari: Ixodidae). This indicates that the latter two species, vectors of 'exotic' tick-borne diseases, remain at low densities in Great Britain and Ireland. Retrospective information on exposure of the animals to different habitats and geographic regions was collected by questionnaire and subject to contingency table and logistic regression analysis. Woodlands and moorlands were habitats significantly associated with I. ricinus attachment. Exposure to urban parks was significantly associated with I. hexagonus attachment and exposure to boarding kennels and catteries was significantly associated with I. canisuga attachment. Ixodes hexagonus, rather than I. ricinus, was the ixodid tick species most likely to be encountered by urban populations of dogs and cats and, by inference, possibly also humans. The implications of these findings, for the transmission of tick-borne pathogens to dogs, cats and humans are discussed.

Evaluation of the effects of nematode parasitism on grazing behaviour, herbage intake and growth in young grazing cattle

Parasitic nematodes, even in the absence of any clinical disease, can cause a reduction in voluntary feed intake in housed ruminants. This trial examined these effects on young cattle grazing pastures. Twenty dairy heifer calves, born in the previous autumn, were blocked according to liveweight and allocated to one of two groups: either untreated or dosed with an IVOMEC((R)) (ivermectin) SR Bolus 10 days prior to turnout on 1 May 1998. The groups grazed separately on two paddocks on predominately ryegrass swards. Liveweights were recorded every 28 days and faecal samples taken for worm egg counts at the same time. In mid-May and mid-July, for two 14-day periods, animals were paired within treatment groups and transferred to one of 10 replicate paddocks of similar sward height and herbage mass. Grazing behaviour and herbage intake were measured during these periods. In mid-May, 2 weeks after turnout, treated and untreated animals showed no difference in grazing behaviour or daily intake of grass. By mid-July, 10 weeks after turnout, the untreated heifers spent on average 105min less per day in grazing time and their daily herbage intake was 0.78kg dry matter (DM) per day lower than that of the treated animals. Residual sward height, mass and composition in the trial paddocks reflected these differences. There were no clinical signs of gastrointestinal parasitism in the untreated group up to this time; in July, the mean worm egg count in this group was 120 eggs per gram (e.p.g.) of faeces. Faecal samples from several untreated animals were positive for lungworm larvae by July, mild clinical signs of bronchitis were observed in two of these animals in mid-July. Over the period from turnout until mid-July, the untreated heifers showed a reduction in mean daily liveweight gain of 150g, compared to the treated animals.