WormFax NSW is (was) a service to NSW sheep producers and their advisors. It was a summary of WormTest results (in sheep) from around NSW. I say ‘was’ because I am retiring (13/7/18) and the service will cease, at least for the time being.
The data for WormFax was supplied each month from two NSW-based parasitology labs: the NSW DPI lab at EMAI and a private lab located at Armidale in NSW. This private lab, formerly part of Veterinary Health Research, is now part of Invetus.
I am most grateful to Invetus (Amanda) and EMAI parasitology (Kathy / Angela / Tammy / Emily) for compiling this data each month and sending it to me. They did this for many years. This has been for the public good, not least for the benefit of primary producers and their advisors etc.
Wormfax (or at least notification (via WormMail) that it was available) was distributed to subscribers via email on a monthly basis. The data was posted on NSW DPI’s website: [ https://www.dpi.nsw.gov.au/about-us/publications/wormfax ]. At the time of writing, the WormFax page and data is still there (perhaps of interest for this wanting to do retrospective analyses?).
The summaries I prepared from the Excel sheets the labs sent me were called ‘WormFax’. This started way back in the late 1980s early 1990s when I was a veterinary pathologist / research officer at the then Regional Veterinary Laboratory, Armidale (RVL-A) (on the site in UNE where Invetus-Armidale (formerly Veterinary Health Research), is now).
(By the way RVL Armidale, established in the mid 1960s, was the first country-based veterinary laboratory in Australia, if you discount the lab that was at the city of Townsville. The first OIC of RVL-A was Dr A (Alan) R B Jackson).
The OIC of RVL-A at the time (1980s/1990s), Dr Robert Coverdale, was keen to make better use of the parasitology data (‘value adding’) generated by the lab. (Bob was the OIC after Dr Bruce Chick left the position and went on to work in the private sector, then eventually starting Veterinary Health Research).
And the local Dept. Agric.Veterinary Officer at the time, Dr Marcus Holdsworth, was keen to be involved. The lab gave Marcus the (de-identified) data each month, and Marcus massaged the data into a monthly newsheet for farmers and advisers. This newsheet contained data summaries and trends and commentary. The newsheet was sent out by fax initially (computers were just ‘happening’ in a bigger way); hence the name WormFax. The other labs (e.g. RVL Wagga Wagga) followed suit, with their own versions of WormFax (but none of the other labs produced as much parasitology data as RVL-A. (The New England region of NSW is a hotspot for internal parasites :-).
Combinations and refugia – ‘in the same breath’ Brucella suis – hunting dogs and people at risk
Further case of Hendra in horse on North Coast
Resources (visual guides) for necropsies -chicken and ruminant – from DAFWA
So, the Kiwis have been cheating?
Why Kiwis thank God they’re not Australian
Pic of week-ABC Rural Roundup
Reading from a screen versus from printed material – Dr Prue Salter
Combinations and refugia – ‘in the same breath’
When talking about combinations, refugia should be mentioned in the same breath. So says (rightly I think), an expert on the subject.
Integrated worm management (not just drenching!) is the preferred approach when it comes to sheep worm control, but sometimes we discuss the individual elements (grazing management, host resistance and resilience, effective well-timed drenches etc) in isolation. But these things are meant to work together.
Here we take combinations to mean a drench product containing unrelated anthelmintic actives with similar spectra of activity against sheep worms, and similar persistency. Often but not always this means a product with unrelated short-acting broad-spectrum anthelmintic actives.
As to ‘refugia’, we mean that proportion of the worm population on farm that is not selected for drug resistance (due to no or inadequate exposure to the drug) when sheep on the farm are treated for worms. Mostly the worms in ‘refugia’ are the free-living stages (worm eggs and larvae on pasture). It can also include inhibited larvae inside the sheep.
Usually there are relatively fewer worms in refugia when conditions are inhospitable for worms on pasture – for example, during a drought – or because of management – for example, ungrazed cereal stubbles, especially in summer.
The current consensus is that using effective combination products is better at delaying selection for resistance in sheep worms than using single-active drenches in some system of rotation. But maintaining worms in refugia is meant to be part of the deal as well.
In practical terms this means, for example, that drenching sheep with an effective combination product immediately before or after moving them onto a very clean paddock, e.g. ungrazed cereal stubble, is not a good idea. There are few worms in refugia, i.e., very few ‘unselected/’drench-susceptible’ worms on the stubble to ‘dilute’ the resistant progeny of those worms that may survive the drench.
Before getting carried away with all this, one of the very basic questions that needs to be asked is whether the sheep actually needed to be drenched at all !, i.e., was a WormTest (worm egg count) done to see if the sheep needed drenching. If the sheep do need drenching, and a move to a clean paddock is intended, then one way to increase the proportion of worms in refugia is to delay drenching (for example, by 2 weeks; but check with your advisor) so they pick up some unselected/susceptible worms before going onto the ‘clean’ paddock. Another option is to leave some sheep undrenched. If the drench was highly effective, 5-10% might need to be left undrenched (again, check with your advisor). An even higher percentage undrenched will be required if the drench is less than highly effective. This strategy is not without risk, especially if pathogenic worms like Haemonchus (barber’s pole worm) are present in numbers. Again, you will need good advice that takes into account your situation.
Below is a nice ‘old’ (2002) summary from British parasitologist Gerald Coles on refugia. (Take time to read the full paper). Experts may not agree with every detail, but there should be consensus on the general principles. Also see links below from WormBoss for further reading.
Coles GC, 2002. Sustainable use of anthelmintics in grazing animals.
The Veterinary Record [01 Aug 2002, 151(6):165-169]
Type: Review, Journal Article
DOI: 10.1136/vr.151.6.165 Abstract It is suggested that the major factor in avoiding the development of anthelmintic resistance is the percentage of worms that do not encounter the anthelmintics (worms in refugia). This in turn is determined by the numbers of larvae on pasture, the percentage of animals treated and whether any stages in the host can avoid the action of anthelmintic. To maintain anthelmintic efficacy the percentage of worms in refugia must be sufficiently large. In cattle, this should involve treating only first-year animals and using a different pasture each year for calves. For sheep, only animals that have to be treated should be dosed with anthelmintic and clean grazing strategies that involve the use of anthelmintics should be avoided. For horses, reliance should be placed on the removal of faeces from pasture and only treating when the animals’ condition requires it. Without a change in anthelmintic use there is the likelihood of increasing numbers of cases for which no anthelmintic is effective and animal welfare may be compromised.
A further case of Hendra was confirmed in an unvaccinated horse on North Coast. According to one veterinary expert: The primary message to all horse owners continues – to protect your horse, yourself, and your family, vaccinate your horse.
“Vaccination remains the most effective way of reducing the risk of Hendra virus infection in Horses, but good biosecurity and personal hygiene measures should always be practiced in conjunction with it,” Dr Middlemiss said.
Resources (visual guides) for necropsies -chicken and ruminant – from DAFWA
Many thanks DAFWA (Dept Ag, WA) and Dr Sarah Britton of NSW DPI.
Check with your lab (e.g., NSW DPI’s SVDL) about their requirements regarding sample submission.
So, the Kiwis have been cheating?
‘Sheepmeat council to vote on Australian lamb definition change next week’
By Terry Sim, 02 August 2017
AUSTRALIA’S leading sheep meat producer body will next week consider seeking a change to the AUS-MEAT lamb language to align with New Zealand’s definition, which includes lambs who have erupted their first permanent incisors.
‘NSW DPI is a major investor in the Australian node of the international ‘Yeast 2.0′ project, based at Macquarie University. The project involves the chemical synthesis of the 16 chromosomes of bakers’ yeast to deliver an entirely new and ‘edited’ yeast, and more broadly will improve our understanding of gene function and regulation, eukaryotic processes, metabolic engineering, and more.This is a key strategic investment by DPI into a new and exciting technology that has the potential to transform agriculture, human health, environmental management.’ – DH
It is a well known fact that those people who most want to rule people are, ipso facto, those least suited to do it. To summarize the summary: anyone who is capable of getting themselves made President should on no account be allowed to do the job. – Douglas Adams, Hitchhikers’ Guide…. http://bookriot.com/2012/05/25/the-42-best-lines-from-douglas-adams-the-hitchhikers-guide-to-the-galaxy-series/ A prescient quote?
Targeted selective treatment strategies for sustainable nematode control and delay of anthelmintic resistance in adult Merino sheep in a Mediterranean environment
Cornelius, Meghan (2016) Targeted selective treatment strategies for sustainable nematode control and delay of anthelmintic resistance in adult Merino sheep in a Mediterranean environment. PhD thesis, Murdoch University.
‘Targeted selective treatment’ (TST) is the concept of targeting anthelmintic treatments to individual animals that will benefit from treatment, rather than giving whole flock treatments. The purpose of TST is to delay the onset of anthelmintic resistance in nematode populations. Two key issues that have delayed the utilization of TST are; a) the need for a convenient and reliable method for identifying animals less likely to cope with nematode challenge; and b) the risk that some animals will be left with nematode burdens sufficient to cause sub-clinical disease that compromises production and welfare. To investigate these issues, this thesis tested the hypothesis that body condition can indicate the ability of mature sheep to better cope with nematodes (and therefore remain untreated), thereby providing a convenient selection method for TST strategies in a Mediterranean climate, where Trichostrongylus spp. and Teladorsagia circumcincta are the predominant nematode parasites. The risk of loss of production and welfare by leaving some animals untreated was examined by modelling simulations, based on data derived from field studies, and on computer models, with various proportions of the flock remaining untreated to determine the threshold proportions of sheep to leave untreated. This approach indicated the trade-offs between delaying anthelmintic resistance with production loss and animal welfare associated with nematode burdens resultant from leaving animals untreated. Further to this, an investigation of Western Australian sheep producers (farmers) identified factors associated with the acceptance of sustainable nematode control practices, especially those likely to facilitate the adoption of TST and act as the basis for the development of communication strategies to producers. The findings of this research provide evidence-based recommendations for the sheep industry regarding sustainable nematode management strategies utilising TST in Mediterranean environments and the facilitation of adoption of TST strategies. In conclusion, the general hypothesis was shown to be applicable, that a body condition score-based TST control program can be practical to implement and will delay anthelmintic resistance in adult Merino sheep in a Mediterranean environment”.
Note that Meghan indicates the context is ‘a Mediterranean climate, where Trichostrongylus spp. and Teladorsagia circumcincta are the predominant nematode parasites’. The concept cannot be transferred unmodified to areas where haemonchosis is endemic. Animals dying from haemonchosis can still be in good body condition. The biggest production loss from haemonchosis is due to death. Death kills productivity. – Ed.
In short, an oral paste formulated for horses, which delivered 200 ug / kg of ivermectin, was ~ 100% effective. However, an injectable moxidectin product for sheep, when given orally to horses (at 400 ug/ kg) (off-label usage), was 72% effective (Despite twice the amount of active! (400 ug vs 200 ug). Assume nothing; extrapolate with caution).
99th annual veterinary conference coming up
The District Veterinarians’ Association of NSW has its 99th annual conference in 2017.
The DVs have a long and proud history, although their contribution to the primary industries of NSW has sometimes been misunderstood or undervalued. Their story effectively begins with the ‘Pastures Protection Boards’ system set up in NSW as result of successful efforts in the 19th century to eradicate sheep scab.
Sheep scab is an acute or chronic form of allergic dermatitis caused by the faeces of the sheep scab mite: Psoroptes ovis (source: SCOPs). (c.f. the other P.ovis (Psorobia ovis (formerly Psorergates ovis); itchmite) – see here). Other countries, for example, the UK, still have sheep scab.
The DVs and PPBs, along with the Department of Agriculture, played central roles in the eradication of TB and brucellosis from cattle in NSW. The national brucellosis and tuberculosis eradication campaign ran for 27 years from 1970 to 1997 and has been followed by ongoing abattoir surveillance (More SJ and Glanville RJ, Vet Rec, 2015). Australia is free of these diseases and was recognised as being free of bovine brucellosis in 1989, and bovine TB in 1997, with freedom occurring earlier in the southern states. Some other countries have yet to achieve freedom. (OK, to be fair to our English friends, they are aiming soon for about half of their country to be officially TB free. And yes, they have had the added challenge of badgers, which can carry bovine TB. As to NZ, “OSPRI’s goal is to eradicate the disease from livestock by 2026, from possums by 2040 and from the whole of New Zealand by 2055.” I guess our trans-Tasman friends don’t thank us for possums or underarm bowling. In the meantime, they wreak revenge through rugby and other activities).
The PPBs pre-dated the Department of Agriculture in NSW, which around that time, was a part of the Department of Mines (if memory serves). Like the Department of Agriculture, the PPBs retained their name for about a century, then (like the Department of Agriculture and everyone else) went through a series of reviews and name changes. The PPBs (roughly 50 of them across the state) became the Rural Lands Protection Boards (fewer and larger districts, each with a board of directors), then changed again into the LHPAs (Livestock and Health Protection Authorities), and most recently, beginning with and related to restructuring of the Department of Primary Industries around spring 2012, combined with Catchment Management Authorities, forming ‘Local Land Services‘, from the beginning of 2014.
The PPBs and their descendants raised their own revenue, mainly by levies on ratepayers (primary producers/farmers).
In the early days, PP Boards had Stock Inspectors. From around the time of the World Wars, these increasingly were formally/university trained veterinarians, and their title changed to ‘Veterinary Inspector’. (I was one of them, from 1976-1986, after a stint in private practice immediately after graduating). Later the name changed again, to ‘District Veterinarian’ (although, in keeping with corporate trends, some of them have other titles as well, e.g., Team Leader of this, that or the other).
When I was a new graduate in private practice (Hunter Valley), I was, like so many others, ignorant in many ways and this included having a pre-formed opinion of PPB and departmental vets without any basis in fact. (Why confuse the issue with facts? Recycled prejudices are much less mentally taxing). My vague notion was that public sector vets were a bunch of office-bound ‘shiny bums’ who couldn’t make it in the real world, and whose main role was to make life difficult for farmers (and real vets) by enforcing regulations and drowning them in paperwork. But, my opinion slowly changed as I was informed by first hand experience and evidence. One of the first veterinary officers I met was one Peter Kirkland. I was doing a ‘caesar’ on a dairy cow and he turned up to collect blood samples for a research project. Peter went on to do his PhD in virology, and over time became an internationally renowned veterinary virologist and head of the world-class virology facility at EMAI. He is just one example. Another one that comes readily to mind is former class-mate, Prof Peter Windsor, who in his early days was a government vet (as were Dr Peter Rolfe, Dr KM Dash, Dr M Smeal, Dr Boray, Prof. Richard Whittington and many other luminaries).
I then became a Veterinary Inspector myself (for almost 10 years, working in various districts), and then worked in a government vet lab for another 10 years. During these periods, I became even better acquainted with a whole lot of veterinary ‘shiny bums’, who turned out to be very good at things other than sitting at desks and watching clocks.
My view now? So after 40 years (as of last week) as a registered veterinarian, it has been my privilege to work with a range of top-notch professionals – veterinarians and non-veterinarians – from different organisations and sectors. And, also a lot of very capable primary producers! (contrary to some stereotypes).
And as to the District Veterinarians? Well, the best of them are in no way inferior to the best of their colleagues in other types of veterinary practice.
So, to the DVs (and many others) I say, ‘thankyou’. Congratulations on a long and proud history, and best wishes for your 99th conference in 2017.
Here another DPI pathologist, Dr Rod Reece shares some avian cases with us:
Ascaridia galli in domestic fowl. L1 & L2 larvae moult occurs within the egg; L3 is released in the duodenal lumen and has a mandatory migration phase in the intestinal mucosa, and must bury the proximal third or so of the body within the mucosa for 5-10 days. A mature adult female A.galli is capable of producing 100,000 eggs per day; 40% of these are released in the early afternoon with 2/3 of total daily output released between midday and 6pm (limited studies). The adult female can reach 7-12 cm in length and 1cm breadth, males are 4- 7cm long and narrower. The adult nematode sits free within the intestinal lumen and maintains its position by undulating movements against the flow of ingesta. Older anthelminthics such as piperazine, narcotize the worms rather than kill them, and they may recover in the cloaca and commence retro-grade movement up the oviduct to be encompassed in a down-coming egg (very rare) or escape free into the abdominal cavity (rarer).
Source: Dr Rod Reece, BVSc, MSc, PhD, FACVSc; Veterinary Pathologist, Registered Specialist in Veterinary Medicine (Poultry); NSW DPI, EMAI-Menangle. Rod also has had experience as a field vet (and is one of the giants).
This is from the July 2015 report for Poultry Health Liaison Group.
Slide/image and notes are from/belong to Dr Reece:
‘Tom Hungerford (ISBN-13: 978-0074525630) quotes 10 as being a significant number of adult ascarids in an adult hen. An adult female Ascaridia galli at peak may produce 100,000 eggs per day; L1 & L2 moulting occurs within the ascarid egg; For the larva to develop fully, L3 must bury their proximal portion in the intestinal mucosa – they do not migrate through the mucosa as some other nematodes do, but they will damage it; The adult worm lies free within the intestinal lumen, maintaining its position by continuous swimming against the contents. Adults ascarids may become displaced, and then resume swimming lower in the gut, if in the cloaca, they may enter the oviduct and become entrapped in a descending egg. This has significant PR implications if found in someone’s kitchen whilst preparing food!’ – RR
Little penguin – parasitism plus
Also from Dr Reece (text and images are his):
” ‘An interesting series of severe parasitisms involved in die-off of juvenile little penguins. They had everything ….nice suckers of Tetrabothrius; megaloshizonts deep in mucosa [gamonts nearby]; acid haematin in duodenum secondary to haemorrhagic gastritis from contracaeca [ascaroidia]. ‘Also liver fluke, renal coccidia, renal fluke, ticks/mites etc, poor feeding capacity …”
Photo source: R Reece
Notes (SL): Tetrabothrius (Tetrabothrium??) tapeworms. There are a number of different species in the Tetrabothrius genus, some parasitising seabirds such as gannets and albatrosses, while others are found in whales. Tetrabothrius sp can accumulate more heavy metals than their hosts. For example, in one study it was found that ‘ T. bassani accumulated twelve times as much cadmium as the gannet’s pectoral muscles. Furthermore the tapeworms had seven to ten times more lead than the seabird’s kidneys and liver. Since these worms seem to act like sponges that soak up and concentrate heavy metals, such substances would reach detectable levels in the tapeworms well before they became noticeable in the host’s own tissues. Because of that, these parasites can possibly serve as early warning indicators for the presence of pollutants in the environment’. Source: Dr Tommy Leung, Parasite of the Day, July 15, 2013.
No, this is not for the ‘blue rinse’ set, but is of interest to registered veterinarians wishing to treat methaemoglobinemia in dogs. I am guessing this is particularly in the context of PAPP (para-aminopropiophenone), a poison for wild canids (wild dogs/foxes), and which causes methaemoglobinaemia (in target and non-target canids). PAPP (originally investigated as an antidote to cyanide poisoning) is regarded as a humane poison. Affected animals becoming sleepy, lethargic, then quickly die, as a result of tissue hypoxia. (Thanks SE)
(The only animals I have treated with methylene blue were dairy cows with methaemoglobinaemia (Nitrate/nitrite poisoning/Sudax). The blue urine the next day was quite memorable. (Dame Edna could have sat behind a treated cow. Cheaper than a hairdresser. And as bonus she might have got a pat on the head)).
I bought a thesaurus at a store yesterday.
Brought it home only to find all the pages were blank.
I have no words to describe how angry I am. (Thanks KQ)
Best wishes to all for Christmas and the New Year, remembering also those in various places doing it tough, some in life-threatening situations, but also, closer to home, friends and colleagues adversely affected by restructuring happening in various organisations here and overseas.
SL, Armidale, 22 Dec 2016
Conflicts of interest: zero
Please accept with no obligation, implied or implicit, best wishes for an environmentally conscious, socially responsible, low stress, non-addictive, gender neutral celebration of the summer solstice holiday (S/hemisphere), practised within the most enjoyable traditions of the religious persuasion of your choice, or secular practices of your choice, with respect for the religious/secular persuasions and/or traditions of others, or their choice not to practice religious or secular traditions at all. In addition, please also accept my best wishes for a fiscally successful, personally fulfilling and medically uncomplicated recognition of the onset of the generally accepted (Gregorian) calendar year 2017, but not without due respect for the calendars of choice of other cultures whose contributions to society have helped make this country great (not to imply that this country is necessarily greater than any other country or area of choice), and without regard to the race, creed, colour, age, physical ability, religious faith or sexual orientation of the wishers. This wish is limited to the customary and usual good tidings for a period of one year, or until the issuance of a subsequent holiday greeting, whichever comes first. ‘Holiday’ is not intended to, nor shall it be considered, limited to the usual Judeo-Christian celebrations or observances, or to such activities of any organized or ad hoc religious community, group, individual or belief (or lack thereof). Note: By accepting this greeting, you are accepting these terms. This greeting is subject to clarification or withdrawal, and is revocable at the sole discretion of the wisher at any time, for any reason or for no reason at all. This greeting is freely transferable with no alteration to the original greeting. This greeting implies no promise by the wisher actually to implement any of the wishes for the wisher her/himself or others, or responsibility for the consequences which may arise from the implementation or non-implementation of it. This greeting is void where prohibited by law. (Transmitted electronically as it would not fit on a card less than A2 in size).(Proximal source: Dr RJD, ca 2000? AD/CE)
Moss Vale district scored the highest strongyle worm egg count, with the average in a WormTest of 2752 eggs per gram (99% Haemonchus), narrowly eclipsing Armidale ( av. 2716, 98% Haemonchus) and the South East region/Local Land services, with an average 2240 epg (99% Haemonchus). The highest liver fluke egg count was 45 epg and this was from Cooma.
Why Haemonchus in winter? It’s eggs are cold- and desiccation-intolerant, but its infective (L3) larvae, not so much. Third-stage (L3) larvae produced in autumn survive over winter, albeit in declining numbers.
Barbervax – the state of play. July 2016
Dr David Smith, Moredun Research Institute, Scotland
Barbervax is a vaccine that protects sheep against barber’s pole worm (Haemonchus contortus). Launched in Armidale, New South Wales in October 2014, it is the first vaccine in the world for a sheep worm and is the culmination of more than 20 years research at the Moredun Research Institute in Scotland. The vaccine is made in collaboration with the Department of Agriculture and Food Western Australia at its Albany laboratory, where the final development phase was funded by Meat and Livestock Australia.
Performance in Lambs
During the last two summers Barbervax has been used in some 250,000 lambs, mainly in the Northern Tablelands, where barber’s pole is endemic and anthelmintic resistance common. Free egg counts were offered to all users so that the performance of the vaccine could be monitored to some extent. Provided the recommended vaccine schedule was followed, lamb egg counts were suppressed to levels below or close to the drench threshold of 1,000 epg recommended by Wormboss (http://wormboss.com.au ). (This threshold has been set to prevent build up of larvae on the pasture and future infection. Clinical signs or deaths caused by Haemonchus don’t usually arise until egg counts reach 5,000 epg or more). Graphs summarising these results can be found at http://barbervax.com.au
Use in adult sheep
Initially Barbervax was registered for lambs only, but permission to use it in adult sheep was granted in late 2015 and so the vaccine will also be available for hoggets and breeding ewes during the forthcoming 2016/17 season. A few producers used the vaccine “off label” in hoggets and ewes last summer. Examples of vaccine performance on some of these properties as well as recommended vaccination schedules for hoggets and ewes whether vaccinated in a previous season or not can be found at http://barbervax.com.au
Barbervax customers will continue to be offered two free worm tests for each class of sheep they have vaccinated during the high risk period (January to April) so that general vaccine performance can continue to be monitored.
Initially the supply of vaccine was limited, but this obstacle has now been overcome and so future production is expected to be able to meet demand.
In addition to the usual 250ml packs, during the 2016/17 season and beyond Barbervax will also be available in 100ml amounts. Using the smaller pack size will be more cost effective when the number of sheep to be vaccinated is not close to a multiple 250.
Thanks to favourable results with trials of Barbervax after prolonged storage, its shelf life has now been extended to 33 months provided it is kept refrigerated.
Attempts to register Barbervax for goats
Barbervax will not be registered for use in goats in Australia in the foreseeable future.
After numerous enquiries from owners, three field trials funded by Meat and Livestock Australia were conducted with a view to registering Barbervax for goats. Unfortunately the results were mixed and for unknown reasons the vaccine did not work on one of the properties. Given the relatively small number of farmed goats in the Haemonchus endemic zone of Australia, it is not considered economically viable to run the numerous trials needed to determine whether the failed trial was an exceptional result.”
Barbervax is available through Grazag in northern NSW. I understand it will be available through Landmark in southern NSW. – SL
Oesophagostomum vs Chabertia
(Oesophagostomum vs Chabertia spp in larval differentiations in lab).
Oesophagostomum and Chabertia larvae are morphologically very similar.
For more detail, see Hutchinson GW, Nematode Parasites of Small Ruminants, Camelids and Cattle, Diagnosis with Emphasis on Anthelmintic Efficacy and Resistance Testing. ANZSDP, 2009. (Figures 1,2; Table 4; pages 23-26 approx)
“In the first version I also did not indicate that the resistance to brown stomach worm involved two species of that worm (Tel. circumcincta and Tel. trifurcata). This might be of interest to just a few.”
In response, a colleague from NZ, consultant parasitologist Dr Paul Mason, offered this comment (with permission to share (all of it)):
Tel. trifurcata (and Tel. davtiani) are minor morphs of Tel. circumcincta, so they are all really one species.
Pharmaceutical companies like to treat them separately as it increases the hit rate on the label claim.
Parasitologists like to treat them separately as we like to be asked to count them separately.
Major and minor morphs are common in the Ostertagiinae (Ostertagia-like worms). …..
27 June 2014, Christchurch, NZ
Old time fluke (chemo)therapy
A paper by Boray and Pearson (1960) came up in discussion with parasitology colleague Maxine Lyndal-Murphy of Queensland.
Just the introduction is interesting. Here is my summary (hopefully free of egregious errors):
carbon tetrachloride discovered to have an anthelmintic effect on hookworm in dogs (Hall, 1921).
carbon tetrachloride found to work against intestinal flukes in dogs (Jeffreys, 1922), and Fasciola hepatica in sheep (Ernst, 1925; Montgomerie, 1926) – an historic step in effective treat. of fluke
Thienel (1926) announced hexachloroethane killed liver fluke in cattle
up to 1960s, these chlorinated hydrocarbons the only effective chem treats. for F hepatica in sheep/cattle
but, not always effective; and sometimes toxic incl death
sodium fluosilicate reported effective against oesophagostomosis – sheep (Mönnig,1933) (Yes, the paper says fluosilicate, not fluorosilicate)
Parnell (1939): sodium fluoride and sod. silicofluoride effective against free-living stages of bursate nematodes of horses and sheep
Sod. fluoride very effective against Ascaris suis in pigs (Habermann et al, 1945) and widely used in pigs until intro. of piperazines
Trifluorotrichloroethane had efficacy against intest. parasites of dog (U.S. Bureau Animal Industry, 1933)
Fluorine-substituted phenols (fluorophenols) found to paralyse A. suis in vitro faster than chlorophenols (Dunker, 1950).
Toxicity of chloro compounds found to be related to number of chlorine atoms and to ratio of chlorine to carbon atoms in the molecule …. the fluorine is so tightly bound in an organic molecule to the carbon that little lionization occurs. Substitution of fluorine for chlorine in the methane series decreases toxicity (Jenkins et al, 1957). ‘This may explain why hexachloroethane is less tox. than carbon tet. and suggests tetrachlorodifluoroethane may be even less toxic.
this paper records the successful use of tetrachlorodifluoroethane against F hepatica in sheep.
Boray, J. C. and Pearson, I. G. (1960), The anthelmintic efficiency of tetrachlorodifluoroethane in sheep infected with Fasciola hepatica. Australian Veterinary Journal, 36: 331–337
Carbon tet: “…originally synthesized by the French chemist Henri Victor Regnault in 1839…….It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent. It is a colourless liquid with a “sweet” smell that can be detected at low levels… Stamp collectors used carbon tet to reveal watermarks on postage stamps without damaging them………The production of carbon tetrachloride has steeply declined since the 1980s due to environmental concerns and the decreased demand for CFCs, which were derived from carbon tetrachloride………..it became apparent that carbon tetrachloride exposure had severe adverse health effects, such as causing fulminanthepatic necrosis ……………..Carbon tetrachloride is one of the most potent hepatotoxins (toxic to the liver), and is widely used in scientific research to evaluate hepatoprotective agents”…. ( I personally have seen hepatopathies in sheep at necropsy after being drenched with CCl4 for liver fluke (one or two older farmers (in the 1980s, Glen Innes district still used it)….”..Carbon tetrachloride persisted as a pesticide to kill insects in stored grain, but in 1970 it was banned in consumer products in the United States…………..” Source: http://en.wikipedia.org/wiki/Carbon_tetrachloride
According to parasitipedia, triclabendazole was released by Ciba-Geigy (which became Novartis) in the 1970s.
The above was referred to by Feinman (Richard D) et al who questioned how far one should go with the need for evidence (e.g. from randomised controlled trials) for medicine (incl. veterinary medicine).
Something I learnt recently (from an entomologist (Dr Garry Levot) when we attended the same meeting).
What I don’t know: did I never know this, or did I forget it? (or both? 🙂
European Union Directive No. 456179 regarding micturation
In order to bring about further integration, all citizens of the United Kingdom of Great Britain and Northern Ireland must be made aware that the phrase ” Spending a Penny” is not to be used after 31 December 2014. From this date onwards, the correct term going forward, will be: “Euronating”.
‘A quick WormMail while I am working on another job.
Here are copies of three PowerPoint slides (see below) from what I am currently working on.
(Hopefully you can make out sufficient detail)
Hugh Mcl Gordon, scientist with CSIR (later CSIRO) developed an early epidemiologically based worm control program. (Australian Vet. Journal (AVJ), 1948 etc).
Keith Dash, also from CSIRO, built on this earlier work somewhat (eg KM Dash AVJ 1986), aided by the serendipitous launch of closantel in Australia (1982), and the two New England Drench Resistance Surveys (1978 (Webb et al AVJ 1979) and 1984 (Love et al AVJ 1992)), which put a bomb under everyone.
Shortly after WormKill’s launch in 1984, DrenchPlan was developed for the non-seasonal and winter rainfall areas of southern NSW. Similar programs were launched in other states