More sky high Trichostrongylus counts – Armidale/Guyra area this time // Join the FAO Animal Nutrition Network??

TO: WormMail list. (recip. undisclosed; cc DVs).    WormMail 2010-04-09

More sky high Trichostronglyus counts -Armidale/Guyra area

So, why am I banging on about these cases?   So that people will take notice.  Even sheep experts sometimes overlook worms, the ‘quiet achievers’.

A bit of history

Here’s the history.  Excuse the typos: it’s not just me who does things in too much of a hurry.

Comment from the Senior District Vet (Dr Steve Eastwood, New England LPHA – Armidale) (Image source:

"Look at the high trich count – not as impressive as what recently occurred at Bourke (Brewarrina) but one of the highest I’ve seen for a while.
The scouring wasn’t that bad, mainly green and our initial concern was coccidia.  The sheep which was pm’ed (16000 eggs per gram) wasn’t scouring at all."

        Elizabeth Macarthur Agricultural Institute
                 Woodbridge Rd Menangle
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Age: 6 Month(s)          Sex: Mixed sex group        No. at Risk: 800                No. Sick: 100                No. Dead: 25


EMAI Parasitology
Nematode Egg Count (Modified McMaster)

Units epg epg
Sample No. Sample ID
0001 1 16400 0 Neg Neg
0002 2 1360 0 Neg Neg
0003 3 6400 0 Neg Neg
0004 4 1280 0 Neg Neg

Comment(s): Insufficient faeces remained in sample 1 to be included in the worm type.

Faecal Egg Count Group Results

Average epg – Strongyle
Average epg – Nematodirus
Units epg epg
Sample No. Sample ID
P001 Pool 2-4 6360 0

Larval Differentiation for WormTest

Units %
Sample No. Sample ID
P001 Pool 2-4 100


* Alas, no pictures. Maybe Libby Read (DV, Narrabri) can give these eastern District Vets/Rangers a few tips  🙂

* There are some very good/informal animal health and ‘grass-roots’ parasitology networks in NSW and Australia.  WormMail – and WormBoss – are portals from these networks out to a wider audience.

Especially WormBoss Monthly News.   Congratulations and thank-you to all the contributors who make the monthly WormBoss news happen.

You -and WormBoss – deserve more kudos!  (Admittedly I am slightly biased  🙂

* Some comments on this case…..

        * Merino weaners were treated with Scanda(R) (BZ/LEV combination) which in this area would still have a good chance of working well against Haemonchus, but maybe a 20% chance of being effective against the ‘scour worms’, Trichostronglyus/Teladorsagia.

        * They were treated with FirstDrench(R). I am not sure why. Tapeworms were in view I guess. I am hoping this is a typo and it was Firstmectindrench(R) (praziquantel + abamectin) which might stand a good chance against the scour worms (and pretty poor odds with respect to Haemonchus, given that >>70% of farms in this region have ivermectin-resistant Haemonchus (with the % being a little lower for abamectin, in view of its higher potency).  

But I guess the main thing is that the praziquantel in this product would have taken care of tapeworm / Monezia). (OK, I am being a tad sarcastic. By the way, Paul Mason (parasitologist, NZ) has reported praziquantel-resistant tapeworm. See the back issues of Turning the Worm on the web  (Issue 22)).

As to FirstDrench (praziquantel + LEV):   The levamisole  component –  ‘maybe a 10% chance of being effective in this region against scour worms; and somewhat better, though worsening, odds (80% ???) of being effective against Haemonchus.

So, the drenching history seems to at least partly explain the lack of Haemonchus, and the (variable) scouring and deaths (due to Trichonstronglyus).

Of course conditions have been excellent for Haemonchus here in northern and north-western NSW (and SE Qld), but, even apart from this drenching history, it is a curious thing that some properties seem to be dominated by Trichostronglyus rather than Haemonchus under these conditions.

* Sky high ‘Trich’ counts? Let’s assume that the necropsied animal (faecal worm egg count (WEC) = 16400 eggs per gram) had a worm burden mostly (~100%) Trichostronglyus, as indicated by the larval culture (drawn from samples 2-4).

* This is among the record high ‘Trich’. counts Steve Eastwood and I have come across, eclipsed only by the astonishing (Trichostronglyus and Ostertagia (Teladorsagia)) counts uncovered by Veterinary Officer Kylie Greentree at Brewarrina.      

WECs = ~ 69 000 and 54 000; larval culture: 86% Trichostronglyus;13% Ostertagia (Wizened old Ostertagiagurus, Dan Salmon (Deniliquin, NSW) and RB Besier (Albany, WA) have pointed out the astonishing Ostertagiacount (as well as the Trichostronglyus) count in this case at Brewarrina).

* If worms are the ‘quiet achievers’ when it comes to sheep (ill)health, then perhaps Trichostronglyus(black scour worm, whether T. colubriformis, T. vitrinus etc) is the quiet achiever among the main sheep worms??.

* You can get fooled and think that every high count is dominated by Haemonchus.

* You may not always get pronounced scouring even with high Trichostronglyus burdens.  Maybe when in extremis these animals get end-stage gut stasis.

* The use of inappropriate or ineffective drenches is a  recurring refrain. (Alliterative but tautological).

Join the  FAO Animal Nutrition Network??

‘Passed on – because it may be of interest to some WormMailees – from Jo Wrigley, formerly of Ancare, Australia and NZ.  

(People like Doug Alcock and Roger Hegarty (I&I NSW- Primary Industries), and Lewis Kahn (UNE) ? etc…immediately come to mind…)

"Please pass on to people you know who could be interested…
Jo Wrigley
mobile 027 247 1691
ph 09 274 7676
fax 09 274 6164"


Veterinarian / State Worm Control Coordinator
Industry and Investment NSW ~ Primary Industries
Armidale District Office

I&I NSW-Primary Industries




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Haemonchosis and high WECs in the northwest and west (NSW) // (pointless?) pontification

TO: WormMail list (recip. undisclosed)    WormMail 2010.04.06.1200

With above average rain in many parts of eastern Australia since Christmas, reports of high faecal worm egg counts (WECs) and clinical parasitism continue to flow in.

For example, Kylie Greentree (Veterinary Officer, Bourke), who recently reported spectacularly high WECs in sheep near Brewarrina (ca. 70 000 epg; mostly Trichostronglyus/Teladorsagia), has also reported high WECs and deaths (~ 200 weaners dead on one farm; presumptive Dx: haemonchosis) in the Enngonia area.

Libby Read, based in Narrabri, sent me the following relating to a case of haemonchosis in young sheep (March 2010) in the Walgett-Lightning Ridge area.  (Used here with permission).

"Outline of the  history:

  * Property visit ~ Monday 29 March 2010

        * Property between Walgett and Lightning Ridge

        *1500 BL x merino lambs, approx. 6 months of age

* Received Weanerguard® in spring 2009    (Weanerguard : injectable moxidectin + multivalent clostridial vaccine)

* Set stocked since January 2010 due to flooding

* Drenched with abamectin on Jan 20 and returned to dirty pasture (due to flooding)

* Approx 100 deaths in the last week

  "It was quite a spectacular autopsy.  An absolute “seething mass” of H. contortus in the abomasum.  Autopsy pics are from the lamb pictured with bottlejaw.


"Vacutainer needle cap for scale…..


Libby "
Libby Read BVSc (N6118)
District Veterinarian
Northwest Livestock Health and Pest Authority
Narrabri NSW 2390  

Some comments (pontification):

* Please note and respect that these images belong to Libby.(My comment, not her’s). I have also added the text (mostly illegible to those with presbyopia 🙂 ) – to the images).

* It was very common to see images (clinical and at necropsy) such as the above in the New England prior to 1982 (and then again, alas, after the early 1990s).

* Such burdens in small ruminants became less common in the ‘Haemonchus’ areas (NE quadrant of NSW; SE Qld)  with the release of closantel in Australia in 1982, particular when used as recommended in the initial versions of the WormKill program (1984 ff).

* But, alas, the ‘WormKill surveillance system’ uncovered the first cases of closantel resistant-Haemonchus from around 1988/1989 in the Warialda district (as reported by Rolfe and others, 1990).

* With the increasing prevalence of closantel resistance (early to mid 1990s), and with the release of moxidectin in 1995, management of Haemonchus relied increasingly on moxidectin, with it’s sustained activity against Haemonchus. Some farmers valiantly augmented this approach with the application of ‘non-chemical’ control options (IPM), including grazing management, which has been promoted for some years (eg early versions of WormKill and similar programs in other states).

* Resistance (as usually defined) of macrocyclic lactones to Haemonchus, especially but not only the shorter-acting and relatively less potent MLs, ivermectin and abamectin, is now common. Although more potent, moxidectin is also now seriously affected by increasing resistance, and this is reflected in attempts to fend off the advance of resistant worms. These efforts include shifting the use of moxidectin (notably Cydectin LA) from the beginning to the end of the Haemonchus season, restricting use as far as possible to vulnerable classes of sheep, and the use of ‘primers’ and ‘exit or tail cutter drenches’. ‘Primers’ and ‘tail-cutters’ of course were and continue to be used with BZ-capsules, which happily are still an option on some properties unless BZ resistance is severe.

* As far as I am aware, there are now no anthelmintic products for small ruminants on the Australian market that are not affected to some extent by resistance. Admittedly resistance may still be uncommon for naphthalophos and multi–combination products.

* As to the latter, there are properties in the ‘H-zone’ (NE NSW/ SE Qld) with resistance even to multi-combination products.  Some producers are now reduced to using OP-based multi-combinations.

* Australian producers look with envy at the Kiwis across the ditch who have the novel anthelmintic, monepantel (Zolvix(R)). The price ($1.20???…admittedly NZ dollars…  🙂    per adult dose) may or may not be an issue (given that animal health is not a large chunk of the cost of production, whereas internal parasites are the number one sheep health issue from an economic standpoint).

* When monepantel (Zolvix(R)) or derquantel/abamectin (Startect(R)-Pfizer) will be registered in Australia is perhaps best answered by the soothsayers. (2011???). The other burning question is, ‘how long will they last??’. If history is a guide (see this Primefact), about 4-5 years (apart from the exceptions to this ‘rule’, levamisole and naphthalophos). Hopefully we will break with tradition.

*In it’s halcyon days (1984 – 1990), WormKill had KISS in spades, largely (but not only!) due to closantel. By KISS, I mean ‘Keep It Simple and Solid’.  (Although some detractors perhaps thought WormKill and its ilk were ‘stupid’ .  With an early adoption rate in excess of 90% (Newman R and others), the farmers of NSW’s New England region seemed to think otherwise  🙂

KISS is currently lacking, especially in H-zones where the Big Three are significant.. You can have SIMPLE or you can have SOLID. But it seems you can’t have both, at least not without the other ‘S’: S for SUSTAINABLE.

Others may disagree, but few if any of them are real farmers. 🙂

Pontificating is easy. Now to a more difficult task which I have been avoiding….

Veterinarian / State Worm Control Coordinator
Industry and Investment NSW ~ Primary Industries

I&I NSW-Primary Industries




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