Parasitology news from Invetus - September 2017

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MERGER AND CREATION OF INVETUS

In December 2016, Veterinary Health Research (VHR) merged with Vetx Research (Australia) and Pharmfirst (NZ) to become Invetus, Australasia’s largest veterinary research organisation.

Dr Maurice Webster, Managing Director, commented “Invetus contributes to the health and welfare of animals and people, by delivering independent, considered and authoritative answers for our partners.

Invetus will maintain the parasite monitoring services provided in Armidale. As Dr Bruce Chick said “parasite monitoring is essential to farmers managing production animals. Our close relationship with resellers who distribute diagnostic kits will continue.”

Invetus provides an extensive range of laboratory services:

                                             - Dr Bruce Chick

                                            - Dr Bruce Chick

  • individual faecal egg counts, fluke counts, larval differentiation
  • worm monitoring
  • drench resistance testing
  • lungworm counts (sheep and cattle)
  • parasite identification & total worm counts

Invetus supplies worm monitoring kits for faecal egg counts (FEC) both directly, and via rural stores. Invetus staff provide recommendations for treatment and further monitoring, with detailed advice available on request.


Broad spectrum drench resistance identified by Invetus

On a sheep farm in Northern New South Wales (NSW) of Australia, a degree of anthelmintic resistance was suspected. With noticeable clinical signs of infection and sheep not responding to treatment, a faecal egg count reduction test was conducted to ascertain the spectrum of anthelmintic resistance at this farm.

  Table 1:  Efficacy assessment. These data indicate the severe level of drench resistance occurring on this farm.

Table 1: Efficacy assessment. These data indicate the severe level of drench resistance occurring on this farm.

The results from this farm shows a high level of resistance to most drench groups, and a reduced efficacy to one of the new drenches (Startect®) on the market. Just because a drench is new doesn’t always mean that it will be 100% effective. The fastest way to introduce resistant worms on any farm is to bring in infected livestock, then fail to remove the worms with an effective quarantine drench.

A faecal egg count performed 10-14 days after a drench as a “drench check” can show that the drench has worked.


Does Barbers Pole disappear over winter?

For many years it was thought that Barbers Pole infections would stop over winter due to the lower day time temperature and frosts at night. The theory was that this would stop the development of eggs on the pasture and therefore infections should decrease. To test this theory, we looked back at our Diagnostic Lab Database from 2015 and 2016, and identified the number of farms from the New England region that had cultures containing Barbers Pole, as illustrated in Figure 1 below.

 Figure 1: Percentage of samples tested positive for Barbers Pole for each month.

Figure 1: Percentage of samples tested positive for Barbers Pole for each month.

The results showed that June 2015 had the lowest percentage of Barbers Pole from the New England region, with 50% of the tests being positive for Barbers Pole. However, although 2015 was a dry winter while 2016 was an unusually wet winter, the results from each month for both years were similar.

The exception was September 2016 by which time the mean temperature was rising. This combined with the wet conditions from the previous months were ideal for the development of Barbers Pole larvae on pasture.

The take home message from this data is that while egg development on pasture during the winter months will slow down, the pre-existing infective L3 stage will actually remain viable for a longer period of time when compared to warmer months, and therefore the risk of new infection is still about.


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For further information, please contact:

Dr Tim Elliott at the Invetus Diagnostic Laboratory

ph +61 (0)2 6770 3200,

or email him at telliott@invetus.com.