Studies on the taxonomy of Strongyloides (Nematoda; Strongyloididae)

The taxonomy of Strongyloides has been critically assessed, firstly from the viewpoint of nomenclature, and subsequently from the aspect of morphology with emphasis placed on the practical problems of differentiating species. On the higher taxon level, the classification of the genus was discussed and placement in the Rhabdiasoidea favoured, although it was acknowledged that this was a compromise based on lack of knowledge of the Rhabdiasidae. The argument was presented that the valid name of the genus is Strongiloides, not Strongyloides, but that adoption of the former name would lead to instability without benefit. One hundred and three names used for species were located in the literature. Fifty three were considered valid, 18 invalid and 32 unavailable. Of this latter group, 22 were lapsi calamorum, 5 were nomina nuda, two had unacceptable spelling, and three lacked a differential diagnosis. The only species names which were considered invalid and are in common use were s.ransomi and S.planiceps, junior synonyms of s.suis and s.cati respectively. The genus was defined by description of the eighteen life cycle stages. This was based on Little (1966a,b) and some additions and corrections made to his basically sound definition of Strongyloides. The proposal was made that the parasitic female lacks cephalic papillae. Some changes in the limits of dimensions of the parasitic female were made, and it was emphasized that the maximum width relative to length, the distance of the vulva from the mouth relative to length, and the intramucosal location of the parasite are significant generic characters. The existence of perivulval nerve endings in the parasitic female was noted. The definition of the free living adults was essentially unchanged from that of Little, with the exception that the midventral preanal papilla of the free living male differs from the six paired caudal papillae. The existence of a papilla on the midpoint of the anterior cloacal lip was confirmed. Artifactual changes in all adult stages were described. The most common were degeneration due to death of worms or their host and those caused by the immune response of the host. The significance of artifactual changes in the taxonomy of Strongyloides was addressed, with particular reference to unusual features described in the literature for various species of Strongyloides. The criteria used to differentiate species in the genus were critically assessed. Those of most use were the stomal shape in the en face view and the ovary. type of the parasitic female, the distribution of caudal papillae in the free living male and features of gubernaculum and spicules, the post vulval constriction and posterior rotation of the vulva in the free-living female, and the stage of the parasite found in freshly voided faeces. Minor criteria were the shape of the tail in the parasitic female, the higher taxon classification of the host, and the occurrence of autoinfective larvae. Practical problems arising in the identification of unknown specimens were discussed. A significant problem not solved by this thesis is that 4l of the 53 valid species have not been adequately described. Consequently, an unusual approach to identification of unknown specimens was developed. This involved the use of a comprehensive host-Strongyloides list to demarcate a series of selection groups comprised of different species. The unknown specimen is compared with the first selection group, and points of similarity noted. Comparison then proceeds through the selection groups whose base broadens progressively. In this way, poorly described species are not omitted from the differential diagnosis. An attempt was made to apply these principles to the Strongyloides sp infecting man in Papua Nuigini. Available information indicated it was most consistent with S.fuelleborni. The nett effect of this thesis is a nomenclatural spring cleaning of the species in the genus, a precise definition of the genus with a clearer demarcation of generic characters, clarification of the significance of artifacts on the morphology useful for taxonomy, delimitation of those characters of use in differentiating species, and proposal of a practical scheme for identifying unknown specimens

Strongyloidiasis in personnel of the Regional Assistance Mission to Solomon Islands (RAMSI)

Objective: to investigate the first reported cases of strongyloidiasis in the Solomon Islands, and to establish whether this disease poses a risk to personnel of the Regional Assistance Mission to Solomon Islands (RAMSI). Design, setting and participants: Retrospective review of the pathology database of the RAMSI Medical Facility in Honiara, Solomon Islands, for the period 1 July 2006 – 30 September 2007. Main outcome measures: number and clinical features of confirmed cases of Strongyloides stercoralis infestation, as diagnosed by serological tests or faecal microscopy. Results: fourteen confirmed cases of strongyloidiasis in previously healthy RAMSI participants were identified. Of 13 patients with notes available, symptoms documented at presentation included epigastric pain (10 patients), diarrhoea (7) and urticaria (4). Clinical disease in all patients responded to oral antihelminthic therapy (albendazole or ivermectin). Conclusions: Strongyloidiasis is endemic in the Solomon Islands and a risk for RAMSI personnel. Australian medical professionals should be aware of this potentially fatal and lifelong infestation, particularly the importance of an occupation history, appropriate diagnostic tests, effective treatment and adequate follow-up to document cure. We recommend implementation of a postdeployment screening program for strongyloidiasis

Immunisation rates of medical students at a tropical Queensland university

Abstract: Although medical students are at risk of contracting and transmitting communicable diseases, previous studies have demonstrated sub-optimal medical student immunity. The objective of this research was to determine the documented immunity of medical students at James Cook University to important vaccine-preventable diseases. An anonymous online survey was administered thrice in 2014, using questions with categories of immunity to determine documented evidence of immunity, as well as closed-ended questions about attitudes towards the importance of vaccination. Of the 1158 medical students targeted via survey, 289 responses were included in the study (response rate 25%), of which 19 (6.6%) had documented evidence of immunity to all of the vaccine-preventable diseases surveyed. Proof of immunity was 38.4% for seasonal influenza, 47.1% for pertussis, 52.2% for measles, 38.8% for varicella, 43.7% for hepatitis A, and 95.1% for hepatitis B (the only mandatory vaccination for this population). The vast majority of students agreed on the importance of vaccination for personal protection (98.3%) and patient protection (95.9%). In conclusion, medical students have sub-optimal evidence of immunity to important vaccine-preventable diseases. Student attitudes regarding the importance of occupational vaccination are inconsistent with their level of immunity. The findings of this study were used to prompt health service and educational providers to consider their duty of care to manage the serious risks posed by occupational communicable diseases

Exposure rate of needlestick and sharps injuries among Australian veterinarians

Background: Needlestick and sharps injuries (NSI) represent an important occupational health issue in veterinary practice. Little is known about the distribution and correlates of NSI among Australian veterinarians. Methods: A questionnaire-based NSI survey was mailed to 1094 veterinarians registered with the Veterinary Surgeons Board of Queensland during 2006. Results: A total of 664 surveys were returned from 1038 eligible participants (response rate 64.0%) with 56.8% being male, around one-third in the >50 years age group and about half aged 3150 years. Just over two-fifths were working in small animal practice only. Around three quarters (75.3%) reported suffering at least one NSI in the previous 12 months, while 58.9% reported suffering from at least one contaminated NSI during the previous 12 months, which crudely extrapolates to an exposure rate of 75.3 and 58.9 NSI per 100 person-years respectively. Risk factors for contaminated NSI were female gender, working in small or mixed animal practice, being less experienced, seeing more patients per week and working longer hours per week. The most common causative devices were syringes (63.7%), suture needles (50.6%) and scalpel blades (34.8%). Conclusion: The exposure rate of NSI is high for Queensland veterinarians and clearly remains a major occupational health problem. Current guidelines and strategies to reduce NSI in veterinary practice should be promoted, but appear to be adapted from human health care. Studies to understand why veterinarians have such high NSI rates are required to not only identify risk factors for NSI, but also to determine attitudes and beliefs about NSI. From these studies specific strategies for veterinarians can be designed and trialed to develop evidence-based guidelines and policies that are effective in decreasing the exposure rate of NSI in veterinary practice

Outcomes of coronary artery bypass graft surgery

This review article summarizes the major studies that have investigated the outcomes of coronary artery bypass graft surgery (CABG). The article includes a review of the literature in the areas of: history of CABG; indications for CABG; and measurement of quality of life following CABG, including prolongation of life, physical functioning (ie, relief from angina and dyspnea, physical activity, as well as complications of surgery and re-hospitalization), psychological functioning, and social functioning. Overall, the literature demonstrates that the outcomes of CABG have historically been measured in terms of mortality and morbidity; however, it has now been well recognized that adjustment to CABG is a multidimensional phenomenon that is not fully explained by medical factors. Therefore, in addition to studying mortality and morbidity outcomes following CABG, many recent studies have identified that it is important to investigate various physical, psychological, and social variables that have a significant impact on post-operative adjustment to CABG

Australian pharmacists' perceptions and practices in travel health

Worldwide, pharmacists are playing an increasing role in travel health, although legislation and funding can dictate the nature of this role, which varies from country to country. The aim of this study was to explore the current and potential future practices in travel health for pharmacists in Australia, as well as the perceived barriers, including training needs, for the provision of services. A survey was developed and participation was sought from a representative sample of Australian pharmacists, with descriptive statistics calculated to summarise the frequency of responses. A total of 255 participants, predominantly female (69%), below 50 years (75%) and registered less than 30 years completed the survey. Although over two-thirds (68%) provided travel-related advice in their current practice, the frequency of advice provision was low (less than 2 travellers per week) and limited to responding to travellers questions. Although Australian pharmacists are currently unable to administer travel vaccines and prescription only medications without prescription, they still consider travel health to be an appropriate role and that their clients would seek travel health advice from pharmacies if offered. Currently, key roles for Australian pharmacists are advising travellers who do not seek advice from other practitioners, reinforcing the advice of other health practitioners and referring travellers needing vaccinations and antimalarials. In order to expand these services, the barriers of workload, time, staffing and the need for training in travel health need to be addressed. In summary, the travel health services provided by pharmacies in Australia still have a way to go before they match the services offered by pharmacies in some other countries, however Australian pharmacist are keen to further develop their role in this area

Examining the dimensions and correlates of workplace stress among Australian veterinarians

Background: Although stress is known to be a common occupational health issue in the veterinary profession, few studies have investigated its broad domains or the internal validity of the survey instrument used for assessment. Methods: We analysed data from over 500 veterinarians in Queensland, Australia, who were surveyed during 2006-07. Results: The most common causes of stress were reported to be long hours worked per day, not having enough holidays per year, not having enough rest breaks per day, the attitude of customers, lack of recognition from the public and not having enough time per patient. Age, gender and practice type were statistically associated with various aspects of work-related stress. Strong correlations were found between having too many patients per day and not having enough time per patient; between not having enough holidays and long working hours; and also between not enough rest breaks per day and long working hours. Factor analysis revealed four dimensions of stress comprising a mixture of career, professional and practice-related items. The internal validity of our stress questionnaire was shown to be high during statistical analysis. Conclusion: Overall, this study suggests that workplace stress is fairly common among Australian veterinarians and represents an issue that occupies several distinct areas within their professional life

Survival of Batrachochytrium dendrobatidis in Water: Quarantine and Disease Control Implications

Amphibian chytridiomycosis is an emerging infectious disease of amphibians thought to be moved between countries by trade in infected amphibians. The causative fungus, Batrachochytrium dendrobatidis, produces aquatic, motile zoospores; infections have been achieved in experiments by exposing amphibians to water containing zoospores. However, the ability of this fungus to survive in the environment in the absence of an amphibian host is unknown. We show that B. dendrobatidis will survive in tap water and in deionized water for 3 and 4 weeks, respectively. In lake water, infectivity was observed for 7 weeks after introduction. The knowledge that water can remain infective for up to 7 weeks is important for the formulation of disease control and quarantine strategies for the management of water that has been in contact with amphibians

Short Communication: A Simple Method for Performing Worm-Egg Counts on Sodium Acetate Formaldehyde-Preserved Samples

The Kato Katz method is the most common way of performing worm-egg counts on human faecal samples, but it must be done in the field using freshly collected samples. This makes it difficult to use in remote, poorly accessible situations. This paper describes a simple method for egg counts on preserved samples collected in the field and sent to a central location for further processing