WRML.2016-09-29.wormfax.products-coming and going.most important thing. Warburg.

In this issue

WormFaxNSW-August 2016

Haemonchus review paper – Emery, Hunt, Le Jambre

Products for worms – ebb and flow

Warburg effect

WormFaxNSW-August 2016

The August issue is now on-line:

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

Many thanks to the State Vet Diagnostic Lab (Menangle) and Veterinary Health Research (Armidale) for supplying summary WormTest (sheep) data each month.

Haemonchus – review – by Emery and others

Haemonchus contortus: the then and now, and where to from here?
David L. Emery, Peter W. Hunt, Leo F. Le Jambre. Int Journal Parasitol 2016

Abstract
Haemonchus contortus (Barber’s pole worm or ‘‘BPW”) is the nematode ‘‘nemesis” of small ruminant production systems in tropical and subtropical regions of the world. Its reputation derives from a combination of high fecundity and a short generational interval that provides an enviable developmental plasticity for adaptation or resistance to control measures.

This review critically examines the historical and current literature on the host–parasite–environment interaction for H. contortus, particularly in sheep, to highlight changes in parasite distribution and ecology on pasture, changes to the seasonal inhibition of fourth stage larvae and the most appropriate models to identify protective responses and assess
vaccines.

The review also proposes pathways to bring host genetics to fruition and avenues where
advances in the parasite genome may complement control measures.
2016 . Published by Elsevier Ltd on behalf of Australian Society for Parasitology. This is an
open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

https://www.ncbi.nlm.nih.gov/pubmed/27620133     (Thanks GAK).

 

Products for worms – ebb and flow

Haemonchus dipstick test – no longer available

‘Merial can confirm they will no longer supply the Haemonchus DipstickTest. Developed in conjunction with the Sheep CRC, this test provided a rapid assessment of Barber’s Pole Worm infection. However, farmers have preferred to use faecal worm egg count tests. This has removed the demand for the Dipstick test.  Farmers who want to continue to use this test should still be able to find supplies at a local chemist.’ (GAK).

(The test uses test strips  (commonly used in diagnostic testing by vets and medical doctors and others) that detect ‘occult’ (hidden) blood in faeces – by detecting haemoglobin  (Hb). The most common reason for Hb in faeces in sheep is Haemonchus. _Ed.)

More information on this test: http://www.wormboss.com.au/tests-tools/tests/assessing-worms.php

Organophosphate (OP) drenches

Australia has had OP drenches for sheep (most of the time) since at least the 1960s. One of the early ones available was naphthalophos (aka ‘naftalofos‘), marketed by Bayer, for the most part as Rametin (Rametin H, Rametin HLV etc).

At various times there have been others, e.g., triclorphon (Neguvon (Bayer)), pyraclofos (吡唑硫磷, пираклофос; combined with albendazole), in Colleague (Coopers). Naphthalophos (alone or in combination with other actives) has been the most used OP in Australia for control of gastrointestinal nematodes in sheep, under various brand names, for example: Rametin (Bayer), Combat (Virbac) and Napfix (Jurox), (and “Pole Vault”!).

However, OP drenches are becoming thin on the ground.

Combat (naphthalophos, Virbac) – no longer available

Virbac advised me in August 2014 that Virbac had made a decision to discontinue Virbac Combat (naphthalophos). (MB)

Rametin (naphthalophos, Bayer) – no longer available

Bayer was having problems accessing the active for Rametin (see here) but have recently advised me that Rametin is no longer being produced. ‘There might still be stocks out in the market as the last batches were released in the last 3-4 months but after that there will be no more produced. It has been impossible to source some of the key ingredients so production has no longer been possible.’ (DD’O)

Neguvon (triclorfon, Bayer) – no longer available

Neguvon has been used for a long time in various animals (In the 1970s, for example, we were were worming horses by stomach tube, using a mix of piperazine, thiabendazole; and Neguvon (the latter for bots)). For a while there was a permit allowing the use of Neguvon to control Haemonchus in goats in Australia  However this permit has expired and I believe Neguvon is no longer produced. (NC, DD’O)  Trichlorfon still appears as an active ingredient of various registered products, including, for example, horse wormers (as a boticide) and insecticides.

Colleague (pyraclofos+albendazole, Coopers)

This was on the market for a while, then went off the market due to mortalities on some properties, then came back, but has now gone again.   (Thanks JM)

OPs tend to have narrower safety indexes (margins) than many other drenches but, at the same time, most deaths tended to be clustered on a smaller number of properties, with many if not most users having few if any problems at all.

A good thing about the OPs is that it has given us another active, and gave good worm control -although generally ‘mid-spectrums’ – especially when used in combination with other, unrelated actives.

Napfix (naphthalophos+abamectin+albendazole, Jurox) -currently unavailable

I hope it and/or other OP-based drenches comes back, for the sake at least of farmers, so they have another option.

Zolvix Plus (monepantel + abamectin, Elanco) – released in NZ

This has been released in New Zealand.  (Thanks PM)

Drenches – the most important thing(s)?

Two things actually…

  • don’t rely on drenches alone.

How not to: http://www.wormboss.com.au/programs.php

  • find out what drenches work on your farm. That’s the first thing to work out when thinking about drenches, not whether to use short- or long-acting, or whether to rotate or use combinations, or what brand to get etc.   See: http://www.wormboss.com.au/tests-tools.php

Warburg Effect

 

 

 

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WRML.2016-09-20.monepantel resistance and reduced efficacy of derquantel/abamectin combination-sheep-Haemonchus -NSW. in Veterinary Parasitol.

This case was first mentioned here:

https://wormmailinthecloud.wordpress.com/2015/09/22/multi-drug-including-monepantel-zolvix-resistant-haemonchus-confirmed-in-sheep-on-a-farm-in-greater-sydney-region/

It has now been published in Veterinary Parasitology:

Sales N and Love S, 2016. Resistance of Haemonchus sp. to monepantel and reduced efficacy of a derquantel / abamectin combination confirmed in sheep in NSW, Australia. Veterinary Parasitology Volume 228, 15 September 2016, Pages 193–196.

Highlights

The first NSW field case of monepantel resistant Haemonchus sp. not associated with goats confirmed.

Monepantel resistance despite only 4 years of previously effective annual use.

Also resistant to abamectin and moxidectin with reduced efficacy of derquantel + abamectin.

Prior treatment with moxidectin or abamectin appeared to increase monepantel efficacy.


Abstract

Early in 2015, sheep in a summer rainfall area of NSW, Australia, displayed signs of haemonchosis despite treatment with monepantel. A faecal egg count reduction test (FECRT) was performed on yearlings with natural field infections using various anthelmintics. Only a four-way combination drench achieved a reduction in faecal egg count (FEC) greater than 95%. The combination contained abamectin, albendazole, levamisole and closantel. Treatments with a derquantel/abamectin combination, monepantel and moxidectin reduced FECs by 93, 31, and 30% respectively. Sheep treated with abamectin displayed an increase in FEC of 22%. Larval differentiation counts conducted 10 days post-treatment showed that 100% of survivors were Haemonchus sp. This result confirms for the first time monepantel resistant Haemonchus in sheep in NSW, and is amongst the first of the Australian cases in sheep not associated with goats. A second FECRT was performed using sheep from the moxidectin and abamectin treatment groups in the first FECRT. In this second FECRT, monepantel treatment reduced FECs by 51% and 29% in the sheep previously treated with moxidectin and abamectin respectively. This suggests monepantel, in combination with moxidectin, may give some control against severely abamectin resistant Haemonchus.

The paper above also gives a brief overview of previous cases of monepantel resistance.

Brief overview – resistance – Australia

Here is a brief overview of drench resistance of sheep worms in Australia:

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0011/70499/Registered-drenches-for-sheep-worms-Primefact-152.pdf

See graph (summarising part of Playford et al, 2014) on page 7 of the PrimeFact.

Managing resistance

See here:

http://www.wormboss.com.au/tests-tools/management-tools/managing-drench-resistance.php

And, most recently, this feature/news article (Sept., 2016) by Dr Lewis Kahn, ParaBoss Executive Officer:

‘Use the right dose of drench: under and overdosing and implications for drench resistance’ [http://www.wormboss.com.au/news/articles/drenches/use-the-right-dose-of-drench-under-and-overdosing-and-implications-for-drench-resistance.php ]

(Bonus with the article: picture of Lewis calibrating a drench gun). (Another reason to subscribe to ParaBoss News).

SL, Armidale 2016-09-20

WRML.2016-09-05. Watt and Bunker – closantel toxicity- XB lambs – NSW

Published here with permission is an article by veterinarians Dr Bruce Watt (LLS veterinarian, Bathurst, NSW) and Dr Erika Bunker (veterinary pathologist, SVDL, EMAI, Menangle).

A CASE OF CLOSANTEL TOXICITY IN CROSSBRED LAMBS

Bruce Watt (Central Tablelands Local Land Services, Bathurst) and Erika Bunker (State Veterinary Diagnostic Laboratory, EMAI, Menangle)

INTRODUCTION

The differential diagnosis of blindness or apparent blindness in sheep on the Central Tablelands of NSW includes polioencephalomalacia, vitamin A deficiency, infectious keratoconjunctivitis, focal symmetrical encephalomalacia and intoxication by Stypandra glauca (nodding blue lily or blind grass) or closantel (and rafoxanide). Ewes with pregnancy toxaemia can also appear to be blind.

Anecdotally, closantel intoxication causing a low prevalence of death and blindness is occasionally encountered by sheep producers on the central tablelands of New South Wales and elsewhere. Several cases of closantel intoxication have been seen at the State Veterinary Diagnostic Laboratory at EMAI Menangle in recent years.

Full article: Watt B and Bunker E Closantel toxicity-XB lambs-NSW- 2 Sep 2016 FINAL

Please respect the intellectual property of the authors including the ownership of the photos.

SL. Armidale. 2016-09-05