In this issue:
Diatomaceous earth and worm control – Whitley and Miller
Cornelius on targeted treatment (PhD thesis)
Drenches for goats – from WormBoss
A case of off-label usage that went wrong
District Veterinarians of NSW – a long and proud history
More history links
Santayana on history
Cases from specialist DPI pathologist, Dr Rod Reece -ascaridia in chooks, and parasitised penguins
Other: other history links, memory, corporate amnesia, seasons greetings, methylene blue and PAPP, pleonasms (the short version)
Dr. Niki C. Whitley and Dr. James Miller
http://www.wormx.info/whatworkswithworms (Thank you, Dr Malan, for inadvertently reminding me of this)
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.
|Publication Type:||Thesis (PhD)|
|Murdoch Affiliation:||School of Veterinary and Life Sciences|
|Supervisor:||Jacobson, Caroline and Besier, R. Brown|
Drenches for goats
Some good info from WormBoss, including how to navigate the legal/regulatory minefield:
An example of off-label usage that went wrong
Further to the above, here is a case from NZ. (It appeared earlier in WormMail: ‘Off-label use of anthelmintics in horses – a NZ case study’ – March 12, 2015)
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.
More PPB/RLPB and other history below:
Some more history in WormMail
PP Board/RLP Board history: https://wormmailinthecloud.wordpress.com/2012/09/29/wrml-history-of-pastures-protection-boards-plus-
A WormKill history- Dr KM Dash: https://wormmailinthecloud.wordpress.com/2014/09/05/wrml-20140905-a-wormkill-history-and-tribute-to-dr-betty-hall-dr-km-dash/
A WormBoss history – LeFeuvre:
Some JC Boray and liver fluke history: https://wormmailinthecloud.wordpress.com/2016/11/03/wrml-boray-on-fluke/
Those who cannot remember the past are condemned to repeat it. – George Santayana (16 December 1863 in Madrid, Spain – 26 September 1952 in Rome, Italy) was a philosopher, essayist, poet and novelist.
(…or needlessly re-inventing the wheel… forgetting the smart wheel designs of old or repeating the duds..)
“If I have seen further, it is by standing on the shoulders of giants.” – Isaac Newton in 1676
Ascaridia galli – chooks
Back in September there was an article from one of NSW DPI’s veterinary pathologists, Dr Erika Bunker, who, with district veterinarian Dr Bruce Watt, reported on cases of closantel toxicity.
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.
‘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.
http://dailyparasite.blogspot.com.au/2013/07/tetrabothrius-bassani.html More information: http://www.merckvetmanual.com/exotic-and-laboratory-animals/marine-mammals/parasitic-diseases-of-marine-mammals
Megaloshizonts and gamonts: these are various stages of coccidia.
Infections with Contracaecum spp are common in wild cetaceans and pinnipeds. ( See Merck)
Methylene blue permit
Dame Edna (sans gladioli). Picture source: unknown
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)).
‘Blair charts new course for LLS’
http://www.theland.com.au/story/4367097/blair-charts-new-course-for-lls/?src=rss&utm_source=The+Land+Newsletters&utm_campaign=eb4c34dd57-newsletter&utm_medium=email&utm_term=0_ade9099b1a-eb4c34dd57-114557597 (‘Must be (getting) thick(er): I don’t understand this artricle. ‘Will have to wait for the outcome).
Do you remember how memory works?
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)