In the spring of 2014 we diagnosed our first case of Theileria, this case involved the death of young beef calves. Since then we have identified infected animals on 2 properties but no real animal health issues had been noted. This spring we have seen our first serious outbreak of Theileria. The case involved a herd of Angus cows that were purchased and shifted onto a new property that previously had been stocked by large numbers of Dairy Grazers.
The owners became concerned after the death of 3 cows, with other cows appearing to be unwell and calves being born dead for no apparent reason. Clinical investigation revealed that the unwell cows and lost calvers appeared to be anaemic, suggesting Theileria, (which causes disease by damaging the red blood cells) was a likely diagnosis. This was confirmed through laboratory testing.
This outbreak occurred in an area where ticks are known to be present and it is likely that infected grazing dairy cows brought the Theileria organism on to the property, infecting the tick population. (Note that this disease only spreads between cattle via ticks, which become infected when they feed on an infected cow).
There is very little in the way of therapeutic treatments for Theileria outside of feeding sick cattle well and minimising stress. Blood transfusions may be an option for high value stock and in some instances treating stock for ticks may be useful to prevent infections occurring at critical times of the year.
Ticks will move rapidly between properties, hitching a ride on their hosts, which can be virtually any mammal (deer, goats, hares, dogs, horses, sheep, etc).
So it is certain that we will see more Theileria outbreaks now the disease is established in our tick population.
The following symptoms could be an indicator of Theileria
Poor weight gain in younger cattle.
Weight loss, especially associated with anaemia.
Calf deaths or sickness.
Death of cows especially around calving time or when cows are stressed.