A study of the serological response to helminths in domestic animals

A study has "been made of the serological responses occurring in domestic animals as a result of natural infestation with helminth parasites. The helminth infestations studied were those of Fasclola hepatica. Cysticereus bovls. Ascaris lumhrlcoides, Dlctyocaulua vlviparus and Trichlnella spiralis,F.HEPATLCA. The serological response, as indicated by the precipitin test, in F.hepatlca infestation was most marked when the immature parasites were in their migratory phase. Thereafter the precipitin antibody level became lowerSpecific complement fixation antibodies were demonstrated in the sera of only one infested animal. This was indicative that the complement fixation technique was unsuitable for the demonstrat¬ ion of antibodies in P,hepatica infestation. Alcoholic extracts of the parasite were found to give varying degrees of r.on specific complement fixation with sheep sera, irrespective of F.hepatica infestation.The miracidia of F.hepatlca were observed to suffer a lethal effect when placed in sheep serum. Complement was necessary for the reaction.Hypersensitivity, demonstrable by an JLOD# Intradermal test, was evident in a large percentage of animals infested with F.hepatica. In some cases this hypersensitivity was passively transferable, "by means of serum, to a non sensitive animal. Local skin desensitisation could "be produced to a marked degree hut generalised skin desensitisation was less obvious when large quantities of antigenic material were administered.G.BOVIS. Precipitin antibodies were demonstrated in the sera of animals which showed multiple eysticerci in the musculature. When only a few (1 or 2) eysticerci were present a serological response was frequently absent. Polysaccharide solutions of the parent parasite, T# saglnata# produced precipitin reactions with the sera of animals infested with P.hepatica only. This was thought to be due to an isoagglutinin like producing antigen present in both T.saginata and hepatlca.Animals infested with F#hepatica produced hypersensitive skin reactions to extracts of C.bovls# A common allergen In the two parasites was thought to be responsible#A.LUMBRIOOIDEA. Precipitin antibodies were demonstrated in the sera of pigs. These were found to bear no relationship to the presence of mature A.lumbricoides In the intestine# They did, however, show a relationship to the degree of chronic focal interstitial hepatitis.Hypersensitivity to extracts of A.lumbricoldes was evident in the majority of swine. This was similar to the precipitin reaction, in that it was related to the degree of chronic focal interstitial hepatitis but not to the presence of intestinal forms of A.lumbrlcolfles.D.VIVLNARUS. The majority of cattle examined showed skin hypersensitivity to D.vivlparue extracts. This hypersensitivity was most evident in the age group 2-j? to 3-j years. The hypersensitivity demonstrated occurred in the absence of parasites. Intestinal helminths did not influence the hypersensitive state.Hypersensitivity was demonstrated in sheep undergoing a sub-clinical infestation with 13.filaria Infestations with other lung worms produced a hypersensitive state which could be demonstrated by D.filaria extracts. This was indicative of a group reaction.T,SPIRALIS. Hypersensitivity to extracts of T.spiralis was demonstrated in only 5# 4$ of swine. Only 0.91 of swine showed marked reactions. Since these occurred in animals possessing marked hypersensitivity to A.lumbrlcoidea it was concluded that a strong hypt rsensitivity to A,lmribrlcoltl.es could sensitise pigs to extracts of T.spiralis. Infestations with T.trlchiura did not produce hypersensitivity to T.spiralis extracts.The use of animals at an abattoir afforded the opportunity to correlate the serological findings with post mortem evidence of infestation. Since the lack of helminth eggs in the faeces does not necessarily indicate absence of helminth infestation the post mortem examinations carried out gave a more complete picture of the parasitic burden. As a result it was found that light infestations or pathological evidence of helminth infestation could be correlated with the serological findings (vide P.hepatica. C.bovls and A.lumbrlcoldes). If faeces examination had been the sole criterion of evidence of infestation no correlation between serological findings and infestation would have been evident and false conclusions may have been drawn

Global health: setting the agenda for veterinary medical education to enable veterinarians to meet their responsibilities in the field

Summary We regard the set of papers in this issue (OIE Rev. sci. tech. Off. int. Epiz., 28 [2]) as a blueprint for an agenda to bridge the divides within the global scope of the veterinary profession, so that it will meet its responsibilities to the world as it develops in the coming decades. It defines the areas with which all veterinary students should be knowledgeable, provides emphasis on the need to expand the education of all veterinary students in terms of their global health responsibilities, and then provides insights into the educational approaches that can result in the inclusion of global health issues within the veterinary curriculum. Keywords Global health -Global veterinary public health -Veterinary medical educationVeterinary profession. Global health: defining, creating and setting the agenda for veterinary medical education In 1986 I (LS) presented my Wooldridge Memorial Lecture entitled 'New horizons for veterinary medicine: can the educators respond?' (40). I identified several issues which were of topical concern at the time, including genetic modification of crops and animals, use of animals to produce pharmacological substances, embryo transfer and the use of genetically engineered growth hormone to increase milk yield in dairy cows, to mention a few. These were the burning issues of some 20 years ago and they focused on cumulative events in veterinary medicine over several decades. Now the issues are quite different. We are now living in a post-Malthusian age and the contributions to this volume recognise the need for the veterinary profession, and thereby veterinary education, to respond to the challenges posed by the coming urgencies. Expert population predictions are accepted as fairly reliable and the issues that come with them are global in nature and urgently need attention. By 2050 it is estimated that nine billion people will inhabit our planet amid global warming, environmental degradation, water shortages and possibly social unrest (24). A vital issue will be the feeding of these nine billion, who will increasingly demand animal protein and will increasingly live in urban communities A recurrent theme in all these issues, whether they are related to climate, food, or disease surveillance and control, is the need for rapid action. But as rapid as we would wish this action to be it does take several years of research before new technology can become a practical reality that is ready for field use. The average lead time required to translate new technologies into commercial products (e.g. vaccines) is at least 10 years, so there is an urgent need to ensure high quality research now to find the solutions to provide food security for the future. An important question in this global scenario is 'Does the veterinary profession have a role to play?' The various contributions to this volume express the wholehearted opinion that it does. If this is so, is the profession prepared to address the global issues and how? Unfortunately, while at present there may be a willingness to do so it is problematic that there is the urgency and the means to design new and innovative programmes in veterinary schools and colleges to address the many issues that will encompass the global scene. As has been emphasised by King in this set of publications (25), the veterinary global community must work in unison; this volume identifies courses of action that must be taken if we, the veterinary profession, are to play an important role in the issues that not only will be upon us in a few decades time, but are already placing animal and human health and welfare under threat. So when in my Wooldridge Lecture I posed the question 'Can the educators respond?' perhaps the question should have been 'Must the educators respond?' and the answer to this is undoubtedly 'Yes'! But there will need to be a radical change of emphasis in the educational programmes of veterinary schools and it is hoped that this volume will be the blueprint for that future emphasis. The world already looks to human medicine to play a critical role in these global issues, but there is little recognition of the world role that could and should be played by the veterinary profession. Is this a failure on the part of the veterinary profession and its leadership to recognise and embrace the challenges posed by these global issues? To engage with these issues would be consistent with the 'global health' concept of 'One World, One Health' proposed by Osburn, Scott and Gibbs (34), who describe it as an integrated approach to animal, human and environmental health, an interdependence that has never been more important or urgent than now. In the coming decades, as emphasised by Kelly (24), the need to produce more food and provide greater security from plagues will involve close cooperation between the medical and veterinary professions, i.e. 'one medicine '. Halliwell (21), in discussing the responsibilities of veterinary educators in responding to the emerging needs of veterinary medicine, identifies the responsibility of national and international organisations as that of providing foresight and vision, and he gives the Foresight Project initiative of the American Association of Veterinary Medical Colleges (55) as an example of a project that envisions a number of scenarios for veterinary education in the years ahead. A 'bold and imaginative' (21) report emerged from the Foresight Project, but Halliwell accepts that change is a long-term process and that any impact upon curriculum developments has yet to appear. The concept of 'one medicine' was mooted as early as the 19th Century by Virchow, a German physician and pathologist who stated, 'Between animal and human medicine there is no dividing line, nor should there be'. Various other authors have put forward the concept of 'one medicine', for example William Osler (35) and Calvin Schwabe (38). In the examination of this concept both medical and veterinary education came under critical scrutiny in the early 20th Century on both sides of the Atlantic. The Flexner Report (17) to the Carnegie Foundation in 1910 lambasted medical education in the United States of America (USA): 'medical schools were private money-making ventures, bickering and feuding were standard means of faculty communication'. The Flexner Report revolutionised medical thinking in North America, sweeping away the apprenticeship system and establishing the concept that research and teaching go hand in hand. This produced an emphasis on science rather than manipulative skills. Veterinary education in both the USA and Europe felt the blast of the Flexner Report and in the United Kingdom (UK) the Second Loveday Report in 1944 (29) recommended that veterinary colleges, hitherto independent, should become part of universities. 'Nothing short of this will give veterinary education the standing and the opportunities for development … which the national economy deserves and requires'. The introduction of comparative medicine (or 'one medicine') into university thought in the UK may be attributed to Sir Clifford Allbut, Regius Professor of Physik in Cambridge, who in 1919 advocated that Cambridge University should set up a Central Institute of Comparative Pathology, saying 'We cannot tell how bright the cross lights which … will be thrown upon the fields of several pathologies of all kinds of life'. In response to Allbut' s Rev. sci. tech. Off. int. Epiz., 28 (2) 862 Rev. sci. tech. Off. int. Epiz., 28 (2) King (25) in his article 'One world of veterinary medicine', 'Today, the veterinary profession sits on the cusp of the greatest period of challenges and opportunities in its history'. These challenges include recognising and responding to zoonotic disease transmission and vector-borne diseases, maintaining food and water quality and promoting wildlife and ecosystem health The elucidation of E. coli O157:H7 infection associated with leafy greens originally identified cattle as the hosts for outbreaks of human diseases. But the fields where the produce (leafy greens) was grown had no direct link to cattle; the role of feral pigs was then examined and they were identified as a source of contamination. After mingling with cattle in pastures some quarter of a mile away the pigs moved into these leafy green fields and defecated there, mechanised harvesters with vacuum pickup systems picked up leafy greens and debris, including pig faeces, all of which was transferred to washing containers where a cooling process placed the E. coli in contact with the internal and external surfaces of the leafy greens. In the field of companion animals it is now recognised that the study of the restricted genomes of many breeds of companion animals offers an outstanding opportunity to provide a joined up approach to research on human and animal diseases in which veterinary schools can provide leadership ('one medicine'). Examples of comparative medical issues or 'one medicine' are combined immuno-deficiency in Arab horses, canine leucocyte adhesion deficiency in Irish Setters, syringomyelia in Cavalier King Charles Spaniels and brachycephalia in Pekinese and Bulldogs. An area which must command increased attention in any veterinary school curriculum and research programme is public health and zoonoses. Of the 1,461 infectious diseases of man, 875 are of animal origin and this ratio is increasing. This is a matter of growing concern, as is the resurgence in antimicrobial medications for food producing animals and the concomitant increase of antibiotic resistance. Of particular note is the recognition that antibiotic-resistant genes are circulating in the environment via commensal organisms. Since the veterinary profession has been accused of causing a substantial proportion of antibiotic resistance problems there is the need to have the prudent use of antimicrobial agents more clearly enunciated throughout the curriculum. The development of antimicrobials is ranked among the most important advances in medicine. Many lifethreatening infections have been controlled while minor infectious morbidity is readily treated. Antibiotic prophylates have made many surgical procedures, transplantation medicine and cancer therapy much safer. The therapeutic effectiveness of antimicrobials differs from other drugs since they target microorganisms as opposed to host-derived pathologies. Unlike other drugs the therapeutic effectiveness is continually threatened by the emergence and spread of resistant organisms. Antibiotic resistance must be viewed as a serious threat to public health. Fanning et al. (15) maintain that current veterinary education programmes do not provide the means to enhance an undergraduate student' s understanding of this situation. As a first step they maintain that a modern education programme should provide students with a holistic view of the ecology of resistance and how it can emerge. The importance of food animal veterinary education is examined by Bravo et al. (8) who identify the need for the curriculum to be adapted to the individual circumstances Rev. sci. tech. Off. int. Epiz., 28 (2) 864 of a country or region. In Europe, for example, in 2010, curricula must be adapted to the guidelines of the European Space for Higher Education and Bravo et al. maintain that it is now time to specify how the veterinary curricula can be most adequately oriented to adapt them to these new requirements. These authors recognise that there is increasing demand for food of animal origin globally, which has highlighted the lack of farm veterinarians in some Western countries, and they note that an increasingly 'urban' mentality is developing in the profession and in veterinary education. In a strongly argued contribution these authors identify that one of the tasks that veterinary professionals are most frequently asked to perform is to guarantee the safety of food production for the consumer, thereby safeguarding human health, without neglecting animal health and welfare. When a country is heavily dependent on meat and livestock exports, as for example Australia or New Zealand are, the veterinary authorities carry an important burden of responsibility for the examination and certification of exported products. Therefore it would be expected that the veterinary curriculum would have a strong public health component. As pointed out by Abbott (1), Craven (12), and Fenwick and Wilks (16, 54), as Australia is the largest exporter of red meat and animals in the world it needs to have a veterinary curriculum appropriately rich and broad in these areas to produce graduates who are able to address challenges in related areas of veterinary public health throughout the world. To this end a Public Health University Network in Australia has been established to harmonise the veterinary public health curricula at the various veterinary schools and to develop the Australian veterinary public health philosophy. The global implications of veterinary public health teaching in Australia are great and teachers in educational establishments recognise that the veterinary profession is a truly global profession and it is integral to the success of the 'One Health' concept. Similarly, Swan et al. (43) emphasise that education in countries in which endemic exotic diseases exist must be tailored to an understanding of the surveillance and control needs, not only for that region, e.g. sub-Saharan Africa, but globally as well. To advance this concept in southeast Asian countries a meeting of the Asian Association of Veterinary Schools has recommended that graduates of veterinary schools in Asia should have extensive training in population health, preventative medicine and zoonotic diseases (57). In some universities veterinary public health is taken further by Master of Science courses, thereby supplementing the undergraduate courses. In South America, Berruecos and Zarco (6) describe the integration of issues of global animal and public health into the veterinary education curriculum. Historically, in most Latin American countries the development of veterinary education followed that of Mexico, with a practical transition from a curriculum oriented towards equine medicine to one that balances animal health, animal production and public health. Concomitant with this development there was a marked increase in the number of veterinary colleges in South America; there are now more than 200, with 160 of them being in Brazil alone. Under the auspices of the Panamerican Association of Veterinary Sciences, the Pan American Federation of Veterinary Schools (PFVS) was created to 'promote modification of veterinary curricula to deliver basic veterinary education according to the political, social, economic, sanitary and environmental realities of the region and to orient veterinary education towards higher emphasis on animal health, quality and efficiency of veterinary services and ethical and environmental consciousness'. This has resulted in curricular harmonisation, with a basic curriculum for veterinary education in Latin America and the recommendation that every veterinary college in the region, regardless of educational methodology or species emphasis, makes sure that its curriculum covers specified areas, two of which are public health, and ethics and social responsibility (Berruecos and Zarco, Projections of problems for the coming decades (e.g. global warming, environmental degradation and food shortages) also include warnings about water and its role in disease transmission, zoonoses and agricultural cultivations. The need for water in food production, in both horticulture and livestock undertakings is obvious and its shortage may well lead to famine, as indeed it already has in some parts of the world. However, waterborne transmission of infectious diseases is of importance to the veterinarian, and Bowman (52) emphasise the need for these to be an essential component of veterinary education. Apart from being the most numerous of companion animals, they serve as vital indicators for marine and freshwater ecosystems and, importantly, as the source of high quality food in many parts of the world. In general, fish production, health and welfare are not as widely taught as they should be and are often relegated to postgraduate programmes such as those at the University of Stirling and the Norwegian School of Veterinary Science. In their contribution to this volume Lipman and van Knapen (28) discuss the need for a different kind of veterinarian, and most certainly there is a growing agreement globally that the curricula hitherto espoused by veterinary schools no longer adequately prepare students to respond to the span of responsibilities that the veterinarian may be called upon to deal with. Lipman and van Knapen If we are to accomplish the changes proposed by the various authors of this volume and prepare students for work in a globalised world then we must retool the educational programmes worldwide (9). De Lamballerie (14) urges the case for an understanding of molecular tools and molecular biology to appreciate epidemiological aspects of disease genetic susceptibility. Stoddard and Glynn (42), Windsor (56) and Malone et al. (32) give a breadth of examples of opening the window on public health to veterinary students. These include 'extern'-ships in various agencies of which there are several willing to take on students. Such opportunities, along with the new curriculum at the University of Calgary, Canada (13), which is based on the 'One World, One Health' concept, are moves in the right direction. Stoddard and Glynn (42) state that within the next 20 years the shortage of veterinary graduates entering public health practice could be as great as 15,000. Capua (10), and Wilks and Fenwick (54) call for a greater understanding of viruses, viral diseases, the epidemiology of their pathology and control options, particularly as they relate to domestic wild animals and birds. Coupled with this is the need for a greater understanding and knowledge of the tools available for diagnoses and control. This also requires new graduates to have an understanding of research and the need for it (19). In particular, new graduates need to know and appreciate the scientific method, how to search the literature, how to formulate and address hypotheses and how to get the information to the appropriate ears. The involvement in research in parallel with the veterinary degree (dual degree programmes) is increasingly seen in some countries. Inclusion of conservation medicine and ecosystem health in the veterinary curriculum worldwide is recommended by Aguirre and Gomez (2, 3) as a means of preparing veterinarians to fulfil critical roles in sustaining global health. Bellemain and Coppalle (5) describe the public health governance issues that must be included in the veterinary curriculum and emphasise that they must be taught in the context of the actual situation in a specific country. An aspect of veterinary education not touched upon in sufficient detail is that of animal welfare. Veterinarians have a special responsibility for the welfare of animals in general and particularly for those under their care. Whether acting as clinicians or policy advisors veterinarians have a special role to play as 'animal advocates' while taking into account the considerations of owners, animal industries and governments (Main et al., Achieving the needed results The authors of this volume of papers clearly strongly subscribe to the need for veterinary graduates to be well cognisant of the breadth of global issues and problems that they have discussed. This especially includes an understanding of the role that the profession must play in meeting the United Nations declared Millennium Goals for feeding the world' s population (39) and the issues that must be handled in protecting and preserving the planet' s ecosystem (3, 41). Veterinarians must receive training that enables them to make an effective contribution to these issues, and the papers in this volume cover the broad range of subject areas that should be included in that training. Critically, it is not just the veterinarians who will be directly working within these areas who need this training, but all veterinarians, since all must be spokespersons for the veterinary profession and must understand the role of veterinarians at global level. To accomplish this critical task they need to have a solid foundation in the range of key areas. Veterinarians in practices must serve as the knowledgeable link to the local communities that they serve. How can these goals be brought about and global public health served by the veterinary community? What clearly would seem absolutely necessary is a significant change in the curriculum in most, if not all, veterinary schools. But to accomplish this is a major problem since many in veterinary education would conclude that even the current curricula are already unacceptably stretched beyond a reasonable educational load and overcrowded with the broad range of subjects that must be taught. The solution, however, cannot be to ignore the issue. Major curricula changes are unfortunately usually very difficult to achieve and indeed, as Turnwald et al. (46) have noted, the difficulties involved in introducing these changes have been compared to the difficulties of moving a cemetery. An added conundrum is that with some teachers there is a cult of complete coverage

The Importance of Organic Content to Fractal Floc Properties in Estuarine Surface Waters: Insights From Video, LISST, and Pump Sampling

To better understand the nature of flocs of varying organic content in estuarine surface waters, Laser in situ Scattering and Transmissometry, video settling, and pump sampling were deployed in the York River estuary. A new in situ method was developed to simultaneously solve the floc fractal dimension (F), primary particle size (d p ), and primary particle density (ρ p ) by fitting a simple fractal model to observations of effective floc density (∆ρ) as a function of floc diameter (d f ), while ensuring that the integrated particle size distribution was consistent with measurements of bulk apparent density (ρ a ). When fractal fits were statistically justified, application of the above methods showed the bulk fraction of organic matter (f org ) to be well correlated to multiple floc properties. As f org increased, d p and ρ a also increased, while ρ p , total suspended solids (TSS), and median floc size decreased. Notably for microflocs, neither F nor ∆ρ was significantly related to either f org or TSS. This indicates that organic matter may partially displace water content within microflocs without fundamentally changing the flocs’ inorganic structure. When pooling multiple samples, a marked decrease in F was seen at the transition to macroflocs, and most strongly for high f org cases. This suggested that settling velocities \u3e_ ~1 mm/s may produce turbulent stresses that tend to tear macroflocs apart. This study also found that when the fractal theory held, ρ p had a near 1:1 correlation with the bulk dry density of filtered TSS, implying that primary particles are tightly bound aggregates of combined mineral and organic component

Prescribing practices for intravenous aminoglycosides in UK cystic fibrosis clinics: a questionnaire survey

Background: Intravenous aminoglycoside antibiotics are widely used to treat pulmonary infection with Pseudomonas aeruginosa in individuals with cystic fibrosis (CF). Over the last decade evidence has accumulated showing that the choice of aminoglycoside and the dosing regimen may help reduce adverse effects such as nephrotoxicity. Methods: We undertook an online survey to determine current practice in UK CF Centres. Results: We received a response from 35/48 (73%) centres. A once daily regimen was used in 30/35 (86%) centres. Around one third had stopped using gentamicin in the last 10 years. In most cases respondents reported changing practice in response to new evidence or evidence based guidelines. Obstacles to introducing evidence based practice were identified both at the level of the CF Centre and the hospital trust. Conclusions: A once daily aminoglycoside regimen is now used in the majority of UK CF Centres. Tobramycin is first line and many centres have stopped using gentamicin. Obstacles to evidence based practice remain in a minority of centres

The use of electric pulse training aids (EPTAs) in companion animals

There is currently little regulation of training and behaviour modification processes in the UK (CAWC 2008) besides measures enshrined in the Animal Welfare Act 2006 and a voluntary Code of Practice launched in 2010 (see: http://www.cawc.org.uk/080603.pdf). This Code is consistent with current UK legislation outside of Wales and emphasises the need to safeguard the welfare of all interested parties involved in the “training contract” (animals and people alike) and the importance of adopting sound scientific methods within the skills base of the practitioner. There is much debate and opinion over whether the use of certain training techniques and devices meet these requirements, especially the use of electric pulse training aids (EPTAs). An EPTA is defined for the purposes of this report as a device designed for use in the training of dogs, cats and other companion animal species, which involves the application of an electric current to the skin to aid the training process. In Wales the use of all electronic collars has been banned ostensibly on animal welfare grounds, including those related to boundary fencing (The Animal Welfare (Electronic Collars) (Wales) Regulations 2010). It has been suggested that there are currently around 350000 EPTAs in the UK, although the number in active use is unknown. Nonetheless they clearly represent a significant practice within the sphere of animal training and it is appropriate that careful consideration be given to their use, especially when there appears to be so much contradictory information available and such passionately held convictions (often linked to ethical and animal welfare concerns) by those expressing an opinion. This report critically reviews current evidence and arguments used both for and against the use of such devices and the conclusions drawn. It highlights gaps in our knowledge and awareness of both theory and practice. Recommendations are drawn on this basis