Theileria prevention in beef systems
FITT FINAL REPORT 13FT12
Year of trial: 2014
Group that proposed the trial: Theileria
Region: Northland
Trial initiator: Jeff Martin
A small trial involving pour-on treatment of R1 cattle for ticks supported the current
recommendations provided by NZ veterinary Association, Beef + Lamb New Zealand and DairyNZ,
regarding the use of acaricides (anti-tick treatments) to prevent disease caused by Theileria
Ikeda.
KEY ‘TAKE HOME’ MESSAGES
•
The key finding of the trial was that a one-off treatment of an acaricide applied to naive calves
had limited value in preventing disease in an area where there is an endemic tick population
infected with Theileria Ikeda.
•
Treating animals with a pour-on containing 10% flumethrin was not fully effective in preventing
infection with Theileria.
•
Treatment was not effective in preventing anaemia caused by this infection
•
Using these products is part of the control of Theileria but cannot be relied on as being
completely preventative.
•
Treating animals with a pour-on tick treatment Flumethrin 10% on arrival to the farm, did not
appear to prevent Theileria infection.
•
Infection happened very soon after arrival to the farm.
•
The effects of the infection were seen within 6 weeks of arrival.
•
Further research is necessary to determine if there are other suitable strategies involving the use
of acaricides to reduce disease. These strategies need to be related to the frequency of
acaricide usage and whether there is greater value in their use where there is only a small tick
population present. The use of acaricides is likely to have value in preventing the spread of ticks
infected with Ikeda when transported with cattle moved from one location to another.
INTRODUCTION – BACKGROUND TO THE PROJECT
Theileriosis is a disease of cattle caused by the parasite Theileria orientalis. Theileria has been
reported in New Zealand since the 1980’s but it had been only the cause of sporadic disease.
Theileria orientalis infection has gone from being seen as an incidental finding to a disease of
cattle in its own right. Most of the attention has been on the effects of new infection on dairy
farms, as this is where there have been the most cases reported, and the most clinical disease and
greatest mortality. The increase in disease has coincided with the identification of a new strain,
Theileria orientalis Ikeda.
The disease causes the destruction and removal of red blood cells from the circulation. The effects
of this are determined by the decrease in red blood cells, as measured by PCV (Packed Cell
Volume (%)), and the speed that this change occurs. In most cases, the animals are making new
red blood cells (regenerative anaemia), but disease is seen when the loss of blood cells is greater
than the rate of renewal.
The signs of low red blood cell percentage, (anaemia) can include:
•
Rapid breathing
•
Slow to shift or stand
•
Pale membranes in gums and/or eyes
These are similar to the signs that can be seen with sheep suffering from Barbers Pole infection
(Haemonchosis).
In many cases the first sign noticed may be sudden death (Mcfadden et al, 2013).
Jaundice, a yellow discolouration caused by a by-product of blood cell breakdown, can also be
seen. In the authors experience jaundice in calves is seen more in the recovery phase than acute
infection.
As with the other strains of Theileria in NZ, the main vector for transmission is the cattle tick
Haemophysalis longicornis (Watts 2013).
At present the main methods being recommended to reduce the spread of Theileriosis and
reduce the severity of infection are based around tick control and good animal management.
KEY AIMS – WHAT WAS THE PROJECT TRYING TO ACHIEVE?
To see if preventative tick treatment stopped infection and disease in calves coming from
Theileria-free areas to farms where Theileria is a known problem.
METHODOLOGY – WHAT WAS DONE IN THE TRIAL?
Trial 1
The trial started on 16 December 2013 with 28 animals enrolled.
It has been common practice for 100 kg beef animals to be brought from outside the district.
Animals moving from areas with no Theileria into areas where Theileria has been recorded are
known to be at risk of disease. On two properties that had committed to buying animals, blood
testing was to be done to check the risk of this practice, and to see if there is an effect of giving
tick control at arrival. Bayticol (Flumethrin 10%, Bayer) was used as the tick control treatment.
The animals were weighed on arrival. Half received Bayticol at label dose rate before they left the
yards, the other half were left untreated (control). Treatment and control animals were run
together for the duration of the trial.
PCV was recorded every three weeks from the start of the trial to track the effects of Theileria as it
was not known when or if disease would show up.
Bayticol was reapplied to the treated animals at 3 weeks.
Trial 2
The trial started on 14 January 2014.
The second trial was on a separate property. It involved 100 animals split into two mobs of 50.
Within each mob there were 25 treated and 25 control animals. In contrast to Trial 1, these groups
were tested at the start of the trial to make sure there was no Theileria present. Testing was
averaged across the group.
As part of the PCV blood testing at 3 weeks, groups were also tested for the presence of Theileria
orientalis Ikeda to see if the animals had come in contact with the disease. This was planned to be
done every 3 weeks until the disease was identified. In both trials there was Theileria identified in
both the treated and untreated animals at week 3.
Any animals showing clinical signs of anaemia or with significantly low PCV were to be removed
from the trial and treated with Buparvaquone (Butalex, MSD). Reference range for PCV is 25 - 40
Based on previous experience, a high percentage of animals with a PCV less than 25, do not go
on to develop clinical signs of disease.
RESULTS
Trial 1 (refer to Table 1)
•
At 3 weeks there was no difference in PCV between treatment and control. At this stage both
groups tested positive for Thelieria orientalisis ikeda
•
At 6 weeks there was a significant drop in PCV in both groups, with the control group
significantly lower than the treatment group. This difference was gone by week 9 as the
treatment group’s average PCV had decreased considerably
•
Four animals were removed from the trial by week 9 (all from the control group). Two had PCV
of 15, two looked anaemic but had PCV within the normal range
•
Animals in both groups became anaemic when PCV was less than 25
Table 1: Average PCV after preventive treatment using Bayticol
Average Packed Cell Volume (PCV)
3 weeks
6 weeks
9 weeks
Treatment group
Control group
Significance
38.5
38.5
Ikeda PCR +ve
Ikeda PCR +ve
Ticks visible
Ticks visible
30.6
26.3
Treatment > Control (p= 0.05)
2/14 anaemic
(PCV<25)
5/14 anaemic
Treatment : Week 3 > week 6 (p<0.01)
26.7
27.6
4/14 anaemic
4/10 anaemic
Control : Week 3 > week 6 (p<0.01)
Treatment : Week 6 > week 9 (p<0.05)
Trial 2 (refer to Table 2)
•
There was no Theileria present at day 0
•
At week 3, both treatment and control groups in both mobs tested positive for Theileria
orientalis Ikeda
•
At week 6 there was a significant drop in PCV in both treated and untreated groups. However,
there was no statistical difference between treatment and control
•
There was no statistical difference in the percentage of animals that were anaemic (PCV less
than 25)
•
18 animals were removed from the results due to incomplete data
•
At week 10 there was no statistical difference in PCV between treated and untreated
Table 2: Average PCV after preventive treatment using Bayticol
Average Packed Cell Volume (PCV)
Treatment group
Control group
Day 0
Ikeda PCR –ve
Ikeda PCR –ve
3 weeks
32.8
33.7
Ikeda PCR +ve x 2
Ikeda PCR +ve x 2
1/43 anaemic
0/46 anaemic
25.1
24.4
Treatment = Control
18/42 anaemic
19/46 anaemic
(week 3 > week 6)(p>0.01)
25.4
26.4
Treatment = Control
18/42 anaemic
8/40 anaemic
Week 6 = Week 10
6 weeks
10 weeks
Significance
Treatment = Control
HOW WILL THE GROUP APPLY THE PROJECT RESULTS TO THEIR
AGRI-BUSINESSES?
•
Care will be taken sourcing animals from areas outside Theileria infected areas.
•
Animals being brought in from other areas will be treated for ticks as there was some effect
from treatment but this should not be relied upon as being completely preventive.
•
Careful monitoring of any new mobs between week 3 and 9, following arrival, should minimise
impact of animals suffering from anaemia.
CONTACT POINTS FOR MORE INFORMATION
Garth Riddle, Bay of Islands Vets
To find out more about other FITT projects, freephone Beef + Lamb New Zealand on 0800
BEEFLAMB or visit www.beeflambnz.com/fitt.
Mcfadden A, Pulford , Lawrence K, Frazer J van Andel M, Donald J, Bingham P. Epidemiology of
Theileria orientalis in cattle in New Zealand Proceedings of the Society of Dairy Cattle Veterinarians
of the NZVA Annual Conference 2013
Mcfadden AMJ, Meyer J, Makin J. An outbreak of anaemia caused by Theileria orientalis.
Proceedings of the Society of Dairy Cattle Veterinarians of the NZVA Annual Conference 2011
Vink D, O’Driscoll A, Briggs S, Moors D, Lawrence K. Farm level management of Theileria oriental
ikeda outbreaks in dairy cattle. Vetscript, Volume 26, Issue 11. Dec 2013
Watts J, Pulford D. Theileria: The risks and the ticks. Vetscript Volume 26, Issue 10. Nov 2013
APPENDICES
Please refer to the websites below for extra information on Theileria:
http://www.beeflambnz.com/theileria
http://www.mpi.govt.nz/biosecurity-animal-welfare/pests-diseases/Theileria-and-anaemia-incattle
http://www.dairynz.co.nz/animal/health-conditions/theileria/
This publication is made possible by sheep and beef farmer investment in the industry. Beef + Lamb New Zealand is
not liable for any damage suffered as a result of reliance on the information contained in this document. Any
reproduction is welcome as long as you acknowledge Beef + Lamb New Zealand as the source.