Understanding successful and unsuccessful landings of aerial maneuver variations in professional surfing.

Although performing aerial maneuvers can increase wave score and winning potential in competitive surfing, the critical features underlying successful aerial performance have not been systematically investigated. This study aimed to analyze highly skilled aerial maneuver performance and to identify the critical features associated with successful or unsuccessful landing. Using video recordings of the World Surf League's Championship Tour, every aerial performed during the quarterfinal, semifinal, and final heats from the 11 events in the 2015 season was viewed. From this, 121 aerials were identified with the Frontside Air (n = 15) and Frontside Air Reverse (n = 67) being selected to be qualitatively assessed. Using chi-squared analyses, a series of key critical features, including landing over the center of the surfboard (FS Air χ2  = 14.00, FS Air Reverse χ2  = 26.61; P < .001) and landing with the lead ankle in dorsiflexion (FS Air χ2  = 3.90, FS Air Reverse χ2  = 13.64; P < .05), were found to be associated with successful landings. These critical features help surfers land in a stable position, while maintaining contact with the surfboard. The results of this study provide coaches with evidence to adjust the technique of their athletes to improve their winning potential.

Tropical pyomyositis in the Solomon Islands: clinical and aetiological features.

A prospective study of tropical pyomyositis (TP) in the Solomon Islands' Western Province followed 48 cases (mean age 10.6 years) from a population of 20,000 Melanesians over a two-year period. 32 patients were under 10 years and the male:female ratio was 1.7. Affected muscle was painful, swollen and often fluctuant but hard and indurated in presuppurative lesions. Abscesses, single in 40 and multiple in 8 subjects, were sited in the large muscles of the buttock, thigh, shoulder, arm and back on 52 occasions (90%). They contained 5-200 ml of pus which invariably grew penicillin-resistant Staphylococcus aureus sensitive to cloxacillin and erythromycin. All phage typable strains were identified as group 2 in contrast to the wider range of types found at carrier sites in otherwise healthy controls. TP was preceded by trauma in 30 cases (63%) and 26 (55%) of the patients had pre-existing pyoderma. Histological examination of clinically unaffected muscle biopsies from 10 subjects with solitary (7) or multiple (3) abscesses showed no abnormality. Serological evidence of previous infection with adenoviruses or myxoviruses was present in the same proportion (41-42%) of controls as of 22 patients tested. The results provide no evidence for antecedent diffuse myositis, viral or parasitic infections or nutritional deficiencies but support the role of trauma in localizing haematogenous skin staphylococci into damaged muscle.

The epidemiology of notified genital Chlamydia trachomatis infection in Victoria, Australia: a survey of diagnosing providers.

Data on 259 notified cases of genital chlamydia infection diagnosed in Victoria Australia in January and February 1995 were augmented by call-back. Risk factor data was available for 221. Patients were primarily adolescents or young adults (median age 23 years); 66% were women. Men were more commonly symptomatic. Persons without symptoms were tested as a result of partner notification, sexual risk, termination of pregnancy, or because of abnormalities on genital examination. Limitations of antigen-based screening tests in low prevalence populations were rarely considered. Although antimicrobial treatment usually accorded with available guidelines, case management was not well geared to reducing the broader issue of risk of this infection in the community. Data management systems for handling name-coded data, and systems for recall and follow-up of diagnosed patients and their partners were often inadequate. Sexual history taking had not generally identified details of sexual partners. Partner notification was generally regarded as the patient's responsibility and professional help with contact tracing was rarely sought. Control of chlamydia will require much greater attention to management issues, particularly contact tracing.

Is HIV screening being requested appropriately? The experience of a Victorian public health laboratory.

From the start of clinical testing for human immunodeficiency virus (HIV) antibody in 1985 until the end of June 1994, the Microbiological Diagnostic Unit tested 134 346 serum samples from 109 391 individuals, identifying 672 as infected. A suitable database, using coded identities, was established from the beginning. Because the sera came from a variety of clinical settings, it was possible to extract information about patterns of requests for tests and about the yield of seropositive cases. The data were able to highlight factors associated with high rates of positive tests that can be lost in amalgamated statewide data. The discovery of HIV-positive females was sporadic and there was a much lower detection rate than from testing males. While males were most commonly diagnosed through specialist venereology services, 61 per cent of diagnoses in females were through nonspecialised practices, often those without previous experience in diagnosis and management of HIV infection. Despite some individual exceptions, the requesting of HIV tests appears generally to have been justifiable (particularly in view of the direction of official preventive campaigns) and not profligate. Overall, where practice was unsatisfactory, this lay less in thoughtless ordering of tests than in failing to include with the specimen the elementary, but vital, epidemiological information requested.

The year of the Salmonella seekers--1977.

In 1977 two major outbreaks of salmonella infection originated in Victoria. The first of these, involving Salmonella Bredeney, continued over some seven months and was traced to contamination of powdered milk-based infant formulae during manufacture. This caused cases of gastroenteritis among young children throughout Australia. Another incident led to the discovery that salmonella serovars were colonising not one, but a number of dairy factories through the State. The second outbreak was of typhoid, stemming from a carrier working in a sandwich bar, and occurred during the course of the first, almost overwhelming public health resources and delaying investigation of the first outbreak. The background, recognition, course, investigation and resolution of these, previously unpublished, outbreaks are described, drawing upon the experiences of authors involved at the clinical, public health and laboratory levels, and preserved, contemporary records. Taken together, these outbreaks directly stimulated radical improvements in the construction and management of dairy factories in the State; initiated the adoption of risk management concepts in food factories; caused the launch of regional regulations compelling notification of salmonellas found in food manufacture; and led to the setting-up of an enhanced national, laboratory-based system for the collection, analysis and dissemination of information on enteric pathogens.

A micromethod for agglutination and antiglobulin tests for antibody to Brucella abortus.

A micromethod has been developed for the standard agglutination and antihuman globulin tests for serum antibodies to Brucella abortus. The test uses a haematoxylin-stained antigen. The test is simple and quick to perform and, in a comparison at two centres involving 367 sera, the micromethod was found to be more sensitive than the classical test. It is highly suitable both for routine serological screening and for large-scale surveys of occupationally exposed industrial groups.

Homosexually acquired gonorrhoea in Victoria, 1983-1991.

OBJECTIVE: To identify trends in the rate of gonorrhoea, particularly homosexually acquired infection. DESIGN: A retrospective descriptive study of records stored in a relational database. Records contain epidemiological, demographic and microbiological data of laboratory confirmed cases of gonorrhoea. SUBJECTS: Individuals with gonorrhoea diagnosed microbiologically in Victoria and from whom isolates were subsequently forwarded to the Microbiological Diagnostic Unit, University of Melbourne, for further bacteriological work for the years 1983-1991. RESULTS: Overall, gonorrhoea is declining in Victoria in the general population but has risen sharply in recent years in homosexually active men. An increased number of cases of rectal gonorrhoea in men has also been noted. An age cohort effect in homosexually active men is only evident for the final year of the study. These men do not tend to acquire gonorrhoea abroad and beta-lactamase producing gonococci are rarely found in this group. CONCLUSIONS: Gonorrhoea in homosexually active men has increased disproportionately to the rate of infection in heterosexual men in recent years, despite intensive education and counselling aimed at the gay community. Implications for risk of acquisition of other sexually transmitted diseases, including the human immunodeficiency virus, are evident.

Separation of Cryptosporidium species oocysts from feces by using a percoll discontinuous density gradient.

Cryptosporidium oocysts were concentrated by an ether-phosphate-buffered saline sedimentation technique and then separated by density gradient centrifugation. This two-step method yielded highly concentrated oocysts largely free of bacteria and fecal debris.

Effect of dose on antibody response to subunit influenza vaccine.

In a group of third-year medical students who were given subunit influenza virus vaccine, the haemagglutination-inhibition (HI) antibody response to A/Victoria/3/75, and the boosting of HI antibody to previously circulating A strains of the Hong Kong subtype were independent of the dosage in the tested range. There was minimal boosting of antibody levels to the Asian strains which circulated during the childhood of the volunteers. The antibody responses to the B/Hong Kong/8/73 component were lower and were dose-related. There was no appreciable increase in the HI geometric mean titre to any of the strains after a second dose.

Effectiveness of low-dose intradermal hepatitis B vaccination. Five years' experience of primary vaccination.

OBJECTIVE: To determine whether intradermal hepatitis B vaccination is an effective procedure. DESIGN: A study of antibody responses to hepatitis B vaccine in 753 medical students. SETTING: Routine vaccination of medical students with intradermal doses of hepatitis B vaccines of various origins. OUTCOME MEASURES: Rates of seroconversion and geometric mean levels of antibody achieved. RESULTS: Seroconversion rates, indicated by antibody to hepatitis B surface antigen (anti-HBs) levels of 10 mIU/mL or more, varied between 82% and 94.7% with different preparations of the vaccine. With a four-dose intradermal schedule over two successive cohorts, Engerix-B (SmithKline Beecham) gave better responses, in this context, than H-B-Vax II (Merck Sharp & Dohme). Any reactions to the vaccination were mild and local. CONCLUSION: The intradermal route is a practical method of vaccination against hepatitis B in healthy young adults when the cost of the vaccine is an inhibiting factor.

Booster doses of hepatitis B vaccine: responses to low-dose inoculations.

OBJECTIVE: To examine the anamnestic response to hepatitis B vaccine in previously vaccinated subjects. DESIGN: Subjects who had received a course of hepatitis B vaccine at least two years previously had a sample of blood taken before and seven days after a low-dose booster of hepatitis B vaccine. SETTING AND PARTICIPANTS: A pilot group of laboratory scientists in the Microbiological Diagnostic Unit; fifth year medical students, University of Melbourne; and a group of ambulance officers from the Geelong Ambulance Depot (Victoria). All participants volunteered after having been informed of the study. OUTCOME MEASURES: Serum levels of antibody to hepatitis B surface antigen (HBsAg) were measured before and after the booster dose of vaccine and, when available, in serum taken a month after the end of the primary course of vaccine, and the changes in antibody level were studied. RESULTS: Although some individuals with a restricted antibody response were identified, most showed a quick response. There was limited evidence that this rise peaked early and began to fall within weeks. CONCLUSIONS: In many subjects, levels of antibody to HBsAg peak early after booster doses of vaccine but the rapid anamnestic response to small amounts of antigen make it probable that effective protection from symptomatic illness may be long lasting, when there has been a satisfactory primary response. This provides an argument for testing for adequate seroconversion after vaccination.

An epidemiological survey of human brucellosis in three Victorian abattoirs.

During the period 1977-1978, a serological and epidemiological investigation was conducted by the Victorian Departments of Health and Agriculture to determine the risk to abattoir workers of exposure to Brucella abortus from infected cattle. Nearly 1000 specimens of serum from workers at three abattoirs were tested for brucella antibodies at the Microbiological Diagnostic Unit. Serum agglutination and antihuman globulin tests were performed by a microtitre technique. Approximately 25% of these specimens gave positive results, with a wide variation in frequency in different abattoirs. Data relating to personal, employment and medical history were obtained by means of questionnaires. An attempt was made to identify risk factors by analysis of this information and the serological results. Within each abattoir, the presence of detectable antibodies was no more likely in people with symptoms than in asymptomatic people working in the same abattoir. However, the proportion of workers with symptoms was much higher in two abattoirs with a relatively high percentage of seropositive workers, than in a third, in which the percentage was comparatively low. There was evidence that the risk of exposure to B. abortus correlated with the percentage of cows in the total yearly "kill" for each abattoir.

A comparison of cytobrush and cotton swab sampling for the detection of Chlamydia trachomatis by cell culture.

A cytobrush was compared with a cotton-tipped aluminium shafted swab for the collection of 2024 paired endocervical specimens for the culture of Chlamydia trachomatis. There was no significant advantage with the use of either device with respect to the number of positive specimens detected or the number of inclusions present in positive specimens. However, the use of cytobrushes resulted in an increased level of cervical bleeding and increased collection of cervical mucus resulting in difficulties in the handling of laboratory specimens.

Diphtheria immunization in adolescents and adults with reduced doses of adsorbed diphtheria toxoid.

A study was undertaken in Schick-positive university students and schoolchildren to determine the diphtheria antitoxin response to vaccines containing a reduced dose of adsorbed diphtheria toxoid. It was found that the majority of participants, apparently previously sensitized, responded with an increase in antitoxin titre to protective levels after performance of the Schick test, or after the first dose of vaccine. A group of non-immune students required three doses of vaccine to reach adequate antitoxin levels to ensure durable immunity. Only one local reaction was observed in the group of 51 students, and this was attributed to an Arthus-type reaction involving the tetanus toxoid component of a combined adsorbed diphtheria and tetanus vaccine.

A fatal case of angiostrongyliasis in an 11-month-old infant.

An 11-month-old boy developed flaccid quadriparesis after two months in Fiji, and was transferred to Australia, where a diagnosis of postinfectious myelitis was made. Despite peripheral blood eosinophilia, eosinophils were not detected in the cerebrospinal fluid, and an infective aetiology was not identified. The patient died of progressive bulbar dysfunction. At autopsy, numerous nematodes, identified as Angiostrongylus cantonensis, were seen in vessels of the lungs, brain and spinal cord, associated with pulmonary abscesses and eosinophilic meningitis. A notable feature was the presence of adult nematodes in the lung.

Fatal granulomatous amoebic encephalitis caused by Balamuthia mandrillaris.

Granulomatous amoebic encephalitis caused by Balamuthia mandrillaris is rare (63 human) cases reported worldwide) and fatal. We report a case in a five-year-old boy who had previously been well. For 18 months, he had had a slowly progressive, granulomatous mid facial lesion, but despite extensive investigation definitive diagnosis was made only with the acute onset of neurological signs in the last two weeks of life, when a brain biopsy specimen revealed amoebic trophozoites and cysts. Infection with B. mandrillaris should be considered in the differential diagnosis of chronic skin lesions with non-specific granulomatous histopathology and negative microbiological test results.

Locally acquired Brachylaima sp. (Digenea: Brachylaimidae) intestinal fluke infection in two South Australian infants.

Eggs of a small intestinal trematode were found in the faeces of two 21-month-old children from the same rural district of South Australia who presented 18 months apart with mild abdominal pain and diarrhoea. Treatment with praziquantel resulted in egg clearance and resolution of gastrointestinal symptoms. A brachylaimid intestinal trematode involving the common house mouse, poultry and introduced European helicid snails is well established in South Australia. Both infants had been seen eating raw snails, and snails from their environment were found to be infected with metacercariae of a brachylaimid trematode.