WRML. wormfax.p-glycoproteins. etc.

In this issue:

WormFax-October

PGP inhibitors

Rommel drove a Skoda

WormFaxNSW – October issue now on-line

See here:

http://www.dpi.nsw.gov.au/about-us/publications/publications/wormfax

WormFax is a monthly summary of sheep WormTest results from around NSW, with data provided by parasitology labs at  NSW DPI’s State Vet Diagnostic Lab (SVDL, Menangle) and Veterinary Health Research (Armidale).

Given above average rain for the last 3+ months, it’s more important than ever to regularly monitor worm burdens using worm egg counts (WECs). And test drench efficacy when you treat: do a WEC on or just before the day of treatment, and again 14 days later.   Money well-spent.

Here is a simple exercise: Let’s say the Gross Margin for your sheep enterprise is $25 per dry sheep equivalent (DSE). Your feed is good (quality/quantity) but the sheep aren’t doing well. You haven’t done any egg counting because WEC on 10 samples costs (ball park figures) about $55 plus about $25 if you want a ‘worm type’ (larval culture/differentiation) done as well. Plus there have been few deaths and just a bit of scouring. ‘Can’t be worms. You start drenching more often anyway, just in case. The sheep do better but not a whole lot better. Your neighbour nags you into doing a DrenchTest. That means two WormTests, one on the day of drenching, and another 14 days later.   Good grief!   That’s about $160 bucks worth ((55+25) x 2). Your Scottish grandfather is rolling over in his grave, especially as you are using a premium drench – whatever that means. The test results come back. It seems the premium drench is about 40% effective against black scour worm and 75% against barber’s pole worm.  Further down the track, you are using less drenches and your productivity has jumped and your GM is up to $33/DSE.   You have 3000 DSEs, so that’s an increase of $24 000.   For an investment of $160.

These figures are wild guesses – and the scenario is an oversimplifcation – but the main point holds true: the return on investment (in WormTesting, DrenchChecks etc) is very, very good.

To back this up a bit: back in the day (several years ago), when Gareth Kelly did his PhD, part of his study – done on real farms in the New England (haemonchosis-endemic area) region of NSW – was on comparing the cost of parasitism on farms with ‘typical’ worm control vs those with IPM (integrated parasite management), as detailed in WormBoss, for example.  Ball park figures: the cost of parasitism on typical farms was ~$11/ewe vs $6/ewe on IPM farms. The IPM figures included recommended levels of wormtesting and drench resistance testing. So, a  difference of roughly $5.  Let’s apply this to say 3000 sheep:  $15 ooo.

P-glycoprotein inhibitors

You have probably heard of PGP inhibitors. Below are a couple of papers if you are interested.   The abstract below (from Lepine and others, 2011) gives an inkling of what this is about. (Private vet practitioners reading this may have heard of PGPs / ‘MDR’ in relation to the test available in dogs (collies etc) to check to see if they have a mutant MDR gene that renders the dog more susceptible to macrocyclic lactone toxicity). (Thanks Dr Ebert)

Parasitic helminths cause significant disease in animals and humans. In the absence of alternative treatments, anthelmintics remain the principal agents for their control. Resistance extends to the most important class of anthelmintics, the macrocyclic lactone endectocides (MLs), such as ivermectin, and presents serious problems for the livestock industries and threatens to severely limit current parasite control strategies in humans. Understanding drug resistance is important for optimizing and monitoring control, and reducing further selection for resistance. Multidrug resistance (MDR) ABC transporters have been implicated in ML resistance and contribute to resistance to a number of other anthelmintics. MDR transporters, such as P-glycoproteins, are essential for many cellular processes that require the transport of substrates across cell membranes. Being overexpressed in response to chemotherapy in tumour cells and to ML-based treatment in nematodes, they lead to therapy failure by decreasing drug concentration at the target. Several anthelmintics are inhibitors of these efflux pumps and appropriate combinations can result in higher treatment efficacy against parasites and reversal of resistance. However, this needs to be balanced against possible increased toxicity to the host, or the components of the combination selecting on the same genes involved in the resistance. Increased efficacy could result from modifying anthelmintic pharmacokinetics in the host or by blocking parasite transporters involved in resistance. Combination of anthelmintics can be beneficial for delaying selection for resistance. However, it should be based on knowledge of resistance mechanisms and not simply on mode of action classes, and is best started before resistance has been selected to any member of the combination. Increasing knowledge of the MDR transporters involved in anthelmintic resistance in helminths will play an important role in allowing for the identification of markers to monitor the spread of resistance and to evaluate new tools and management practices aimed at delaying its spread“.

(ABC = ATP-binding cassette (ABC) transporters. None the wiser?  Me either.).

Regarding the safety of macrocyclic lactones in mammals:

” Mammalian safety appears to depend on p-glycoprotein activity in the blood-brain barrier. A p-glycoprotein deficiency in certain animals decreases the ability to pump avermectins, milbemycins, and other drugs across cell membranes”  “There have been cases of CNS depression in cattle breeds (Murray Grey) and in individual dogs of multiple breeds, but these were first recognized in purebred and crossbred Collies.”  Source: http://www.merckvetmanual.com/mvm/pharmacology/anthelmintics/safety_of_anthelmintics.html

Lespine A and others, 2011. Review: P-glycoproteins and other multidrug resistance transporters in the pharmacology of anthelmintics: Prospects for reversing transport-dependent anthelmintic resistance. Int J Parasitol.

Razaa A et al 2015.Effects of third generation P-glycoprotein inhibitors on the sensitivity of drug-resistant and -susceptible isolates of Haemonchus contortus to anthelmintics in vitro. Veterinary Parasitology
211. 1–2. 30 June 2015 pp 80–88

If you are not too proud to read wiki (with discernment, as with everything):

https://en.wikipedia.org/wiki/P-glycoprotein

Skoda Superb – Rommel had one

https://en.wikipedia.org/wiki/%C5%A0koda_Superb_(1934%E2%80%931949)   (Thanks B Y)

Regards,

SL, Armidale

Competing/conflicting interests: none to declare  (Trust me: I work for the government)

My antecedents were Scottish: I can mock them as much as I like. It’s the Australian way.

outlook.combos vs rotation.responses to boray on fluke.giant liver fluke.cattle parasites-UK. etc

In this issue:

  • Outlook from the outhouse
  • Combinations vs rotations – not just about models
  • Responses to ‘Boray on fluke’
  • Removal of giant fluke (rating:PG)
  • Cattle parasites – UK
  • Why photos display incorrectly
  • Word crimes
  • Worm juice for asthmatics
  • Comment on US election

Outlook

It’s a no brainer that we are in for a very wormy spring and summer in NSW, unless conditions suddenly turn hot and dry.

Over the last 3 months, rainfall for NSW has been ‘above average’, ‘very much above average’ or ‘highest on record’ – depending on where you are in the state. Only sections of the coast have scored average rain, according to the Bureau of Met.

Here are three things that will make worms of grazing livestock even more of a problem over the coming months:

* not doing regular worm egg counts (WECs)

* not preparing low worm-risk paddocks for vulnerable stock (young or late pregnant/lactating)

* inadvertently using drenches rendered less effective by resistance

It’s not too late to remedy these things.

If you are weaning lambs in say late January, you can still improve the proposed paddock wormwise. (See WormBoss-Your Program).

Under current conditions, and if you are in the eastern half of NSW, start doing WECs every 4 weeks.   Next time you drench, do a WEC on the day of treatment and retest 14 days later.  Big benefits for relatively small costs.

Weaner cattle will be picking up lots of Ostertagia this spring in many areas. And Haemonchus as well, as a bonus, on the coast. Monitor WECs, but remember a low WEC in cattle may not always mean low worm burdens (sad but true), hence the need to monitor growth rates – and other potential signs of ‘worminess’ – as well.

Like sheep and goat producers, many with cattle will be using less than highly effective drenches, due to resistance.

Consider checking drench efficacy, the same as with sheep. If in doubt, use a cattle drench that is a combination of unrelated broad-spectrum actives. (There are only two of these currently on the market in Australia). In fact, using combination drenches are probably a good idea anyway.

And then there is liver fluke. Temps are now generally mild to warm and there is plenty of moisture. This is seventh heaven for liver fluke and its intermediate host snails.  The fastest fluke can complete one life-cycle is about 17 weeks, and they will just about achieve that under current conditions.

Alas, there is resistance to flukicides too, so keep that in mind. If checking flukicide efficacy, the time to test is on the day of treatment and again 21 days later. This is the simplest approach. (Get good professional advice on this). The appropriate tests are either a fluke egg count or the new coproantigen (faecal fluke antigen) test. The fluke antibody ELISA test is about the most sensitive of current tests for liver fluke, but it is inappropriate in this case because the antibody can take weeks to go down after all fluke have been cleared out by an effective treatment.

As always get good information and professional advice. Some good sources: wormboss.com.au; NSW DPI PrimeFacts; a veterinarian or other worm-savvy adviser.

For parasite news across Australia, subscribe to ParaBoss News:  http://www.paraboss.com.au/news.php

Combinations vs rotations – it’s not just about models

Further to a recent post on this subject…

At the risk of sounding patronising, the evidence advanced for the superiority of using combinations of drenches (using unrelated actives concurrently) vs rotation of single actives – of resistance management –  is not just based on computer models.

Here, for example, is one of several studies drawing the same conclusion  as the models:

Leathwick DM, Waghorn TS, Miller CM, Candy PM, Oliver A-MB.  Managing anthelmintic resistance, 2012. Use of a combination anthelmintic and leaving some lambs untreated to slow the development of resistance to ivermectin.  Veterinary Parasitology 187, 285-294, 2012.

Click link above for abstract – and full text if you have access.

Combinations are not a silver bullet; they are one part of an integrated approach to worm control. See WormBoss-Your Program.

Responses to ‘Boray on fluke’

Responses from two eminent parasitologists:

[1] I visited dr Joe Boray with dr. Dieter Düwel (fenbendazole-Panacur) in his laboratory in Australia. I honour him as the Fasciola/Snail breeding KING of the world. He made a mighty impression on me. Congratulations on your 90th birthday. Regards, Faffa Malan
 [2] My sincerest congratulations, Joe, on having reached this milestone, and in such good shape ! You’ve been one of the outstanding examples to have stimulated my research career and I’m very honoured to have been able to meet you at the start thereof in 1968, and to have met up with you repeatedly over the years.
Everything of the very best for the future !
Jan van Wyk

Removal of giant liver fluke (Fascioloides magna) from a white-tailed deer’s liver

Published on Jun 17, 2016 Removal of Giant liver flukes (Fascioloides magna) from a white-tailed deer liver. See more at:  jtvannatta.wordpress.co

The liver fluke we have in Australia, Fasciola hepatica, is ~ 30-50 mm long x 10 mm wide and leaf-shaped. Fasciola hepatica is the most common cause of liver fluke disease in temperate areas of the world, and the most important trematode of domestic ruminants.

The other fluke in the Fasciola genus is Fasciola gigantica (75 mm x 12 mm). These three fluke (F.h., F.g, and Fascioloides magna) are in the family Fasciolidae. Their bodies are large and leaflike with suckers close together at the anterior end. The caeca have numerous diverticula (small side growths) and the ovary and testes are dendritic (branching, like a tree). All three are parasites of the liver and bile ducts of herbivorous animals and humans. (Georgi’s Parasitology, and Merck Vet Manual).

Fasciola gigantica is economically important in Africa and Asia and is also found in Hawaii. Fascioloides magna has been reported in at least 21 states (USA) and in Europe. Fascioloides magna is up to 100 mm long, 2–4.5 mm thick, 11–26 mm wide, and oval. It is found in domestic and wild ruminants; deer are the reservoir host. The life cycle resembles that of Fasciola spp (Merck).

Cattle parasites – a useful website

cattleparasites.org.uk

There is also a Welsh version:

http://cattleparasites.org.uk/guidance/Cows%20Farmer%20Leaflet%20Welsh.pdf  (…for Brythonic language speakers allergic to Sassenach 😉

Why photos sometimes appear incorrectly rotated

http://www.howtogeek.com/254830/why-your-photos-dont-always-appear-correctly-rotated/

Word crimes

Worm juice for asthmatics

http://www.abc.net.au/radionational/programs/breakfast/science-with-chris-smith/7973524

http://www.abc.net.au/radionational/programs/breakfast/hookworms/7973502

Comments on US election

Nil, none, nichts, nada.

Just WormMail?

A (former?:-) friend/colleague asked me if I did anything apart from WormMail.

“Not even that”, I said, “WormMail is ghost-written”  (Or do I have a goat-writer?)

Regards,

SL (or ghostwriter), Armidale

‘I work with parasites, and help people with worms’

Conflicts of interest: zip