Novartis has a website for the new anthelmintic, monepantel (Zolvix). http://www.zolvix.com
As mentioned in previous WormMails, monepantel, recently launched (31 March) in Queenstown, NZ, belongs to the new drench group, the AADs (amino-acetonitrile derivatives)
Doing a Drench Test
Are you or a client contemplating doing a Drench Test (faecal worm egg count reduction test – FECRT)?
There is a guide in the NSW DPI Vet Lab Manual. http://www.dpi.nsw.gov.au/agriculture/vetmanual/specimens-by-disease-syndrome/diseases_of_livestock/anthelmintic_resistance
Some of the details may be a little dated, but it gives a good outline.
Quick and Dirty Test – DrenchCheck
Whether or not you do a ‘proper’ drench test, it is good to also do occasional checks on the trot. To do a so-called DrenchCheck, collect samples from a mob of sheep 10-14 days (in the case of short-acting drenches) after they were drenched. You can refine the test still further by collecting samples on ‘day zero’ – the day of drenching – as well.
Consider getting a larval culture done (‘worm type’) as well: this will give you more useful information.
Worm egg counting
View short video clips about worm egg counting at the WormBoss website. http://www.wormboss.com.au/LivePage.aspx?pageId=374
In the space of a week I have had two conversation regarding suspected naphthalophos-resistant Haemonchus (barbers pole worm).
Naphthalophos of course is marketed as Rametin (Bayer), and also in recent years as Combat (Virbac) and Pole Vault.
I know of only two published reports of confirmed naphthalophos resistance in Australia:
* Green PE, Forsyth BA, Rowan KJ and Payne G (1981). The isolation of a field strain of Haemonchus contortus in Queensland showing multiple anthelmintic resistance. Australian Veterinary Journal 57(2): 79–84.
* Le Jambre LF, Geoghegan J and Lyndal-Murphy M (2005). Characterization of moxidectin resistant Trichostrongylus colubriformis and Haemonchus contortus. Veterinary Parasitology 128: 83–90.
From time to time, other instances of resistance to naphthalophos on Australian sheep farms have been suspected. To my knowledge, none of these have been confirmed, which is not to say that it won’t happen.
When naphthalophos resistance in Haemonchus is suspected, one matter to investigate is whether the burden at the time of treatment was dominated by immatures and adults. While naphthalophos is near to 100% effective against adult Haemonchus contortus, it is reportedly (pers.comm.) only about 70% effective against immatures , more or less in the usual range of efficacy that the drug has always had against (adult) Teladorsagia (Ostertagia) circumcincta (small brown stomach worm), and Trichostrongylus species (black scour worms).
NAP – a ‘mid-spectrum’ drench – is commonly used in combination with broadspectrum drenches, including levamisole and/or benzimidazoles, and also, more recently, macrocyclic lactones. This is to increase efficacy, and also to provide the potential ”resistance slowing’ benefits of a combination. NAP and LEV and/or BZ in combination also provides a non-ML rotation option.
NAP combined with LEV and/or BZ can give surprisingly good results, even with considerable resistance in the scour worms to the LEV and/or BZ actives, but results can be quite variable. Some of the multi-drug resistant Teladorsagia isolates in WA are becoming increasingly difficult to control with these combinations, but how much if any of this is due to NAP-resistance is unclear to me.
In any case, the general advice applies: always test the drenches or drench combinations you may want to use on your property. And once adopted, do follow-up testing from time totime using DrenchChecks.
Extras (below; not necessarily worm-related)
* New cattle disease
* Sydney’s cryptosporidium outbreak (by the way, we are still working on a Primefact about Zoonoses)
* Hormone myths and blindspots
Veterinarian/State Coordinator-Internal Parasites,
NSW DPI – Armidale District Office
New cattle disease to rival mad cow disease
LONDON, April 1 AFP|Published: Monday April 1, 1:50 PM
Veterinary Researchers in the UK have discovered a new cattle disease that could be worse than mad cow disease. There is no known treatment for the disease, which has no clinical signs and which is impossible to detect through laboratory testing. Fortunately no cases have been reported so far.
CRYPTOSPORIDIOSIS – AUSTRALIA : (NEW SOUTH WALES) From ProMed
Crypto clue: one person to blame for outbreak
Genetic testing has revealed that Sydney’s cryptosporidium outbreak
may have stemmed from a single infected person. The finding means it
is unlikely that an infected animal or environmental conditions, such
as the weather, are to blame. Since the beginning of last month
[February 2009], when the latest outbreak appeared, 628 people have
fallen ill, compared with 482 in all of last year .
Macquarie University researchers say their testing is experimental,
and unlikely to identify the origin of the current outbreak, but they
hope their work will lead to the development of a world-leading,
inexpensive automated test to quickly identify parasite strains
involved in future outbreaks, allowing sources to be rapidly traced
and infections contained.
Michelle Power, of Macquarie’s biological sciences department, said
cryptosporidium outbreaks were difficult to trace using existing
technology. There are 2 key parasite “species” that infect people:
_Cryptosporidium hominis_, only contracted by direct human to human
contact, and _Cryptosporidium parvum_, which can also be transmitted by
animals. For each type there were about 40 different strains.
However, virtually nothing was known about which strains were
responsible for most outbreaks. A decade after the contamination of
Warragamba Dam, which forced Sydneysiders to boil their water, “we
still just know that it was cryptosporidium,” Dr Power said. “To put
it simply, we’re looking for the easiest way to fingerprint the organisms.”
With the new test it should be possible to compare results from
individual patients to seek common patterns.
“We could look to see if they had all eaten at the same restaurant,
or been to the same day-care centre or swimming pool.”
The NSW Health Department has provided hundreds of fecal samples from
the latest outbreak for testing by a Macquarie University parasite
researcher, Liette Waldron.
“We have analysed about 250 samples from the current outbreak, and
they are all the same strain” of _Cryptosporidium hominis_, Dr Power said.
If it had originated from different sources she would have expected
to see multiple strains. When sporadic cases, reported over the past
12 months, were analysed they identified 24 strains, involving both
the human and animal species.
Dr Power said people who were infected, but not necessarily appearing
ill, usually had 5000 to 10 000 parasites per gram of faeces.
However, some samples from the latest outbreak contained more than 1
million. “The more parasites you see, the more nasty it is.”
Over the next 2 years the project, funded by the Australian Research
Council and the Health Department,will “fingerprint” parasites from
up to 4000 cryptosporidium patients.
[Byline: Richard Macey]
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 31 Mar 2009
Source: The Sydney Morning Herald [edited]
[Genetic fingerprinting is a very useful tool to identify the spread
of microorganisms in a community and thus to help identify the source
and transmission routes. The new knowledge that the outbreak
probably has a single human source underlines the importance of
interrupting transmission to control the outbreak. – Mod.EP
Life-cycle diagram of _Cryptosporidium hominis_ at:
Electron micrograph of _C. parvum_ at:
– – Mod.JW
A map showing the location of New South Wales in Australia can be found at:
– – CopyEd.EJP]
Hormone myths and blindspots
‘Interesting that so many believe that hormones are used in Australia in chicken production, but have a blindspot regarding hormones in milk.
Chicken reference: http://www.abc.net.au/rural/sa/content/2006/s1673928.htm
Cow milk reference: The Paleo Diet Update Issue: # 2009 – 14 /April 3, 2009 Prof. Loren Cordain, Ph.D. www.ThePaleoDiet.com