Following earlier advice to farmers in May this year, the Ministry for Primary Industries (MPI) is again advising farmers to be on the lookout for signs of Theileria infection in their cattle, with a growing number of cases being reported in the northern half of the North Island.
Theileria (Theileria orientalis) is a blood-borne parasite which is primarily transmitted by ticks. It may cause anaemia in cattle and can, in a small percentage of cases, be fatal.
MPI Acting Director General Scott Gallacher says we are currently seeing an increase in cases of an illness that infects cattle but cannot affect humans.
“Theileria is not a food safety issue as it cannot be passed into milk or meat.
“It is, however, important that farmers are aware of the situation to minimise impacts on their herds and their livelihoods,” Mr Gallacher says.
Farmers are being encouraged to look for signs of anaemia in their cattle. These include lethargy (tiredness and lagging behind others), pale skin around the genitals and on the udders, and increased respiratory and heart rates. Stress and movement of affected animals should be minimised, as their reduced capacity to transport oxygen around the body can lead to collapse and death.
Some animals infected with Theileria may show no signs of illness. Sickness is seen where animals do not have immunity (when they have not been exposed to the parasite before) or in animals that are stressed (for example at calving or where there are concurrent infections).
“Anyone noticing this kind of general illness in their cattle should contact their veterinarian in the first instance. Veterinarians can provide advice on how to manage ticks and help prevent further cases. Vets and pathologists with test results identifying Theileria should report cases to MPI on 0800 80 99 66.”
MPI is working closely with the animal industry bodies and the New Zealand Veterinary Association (NZVA) to determine the scale of the situation, build knowledge, inform farmers and carry out research into effective management of the disease.
Theileria has been present in New Zealand for over 30 years, but since late 2012, a strain of the parasite which has not been previously identified in New Zealand has been detected and there has been a spike in the number of disease cases appearing. The first reported cases appeared in cattle in Northland in August 2012. The majority of cases to date have been confirmed in Northland, the Waikato, King Country and the Bay of Plenty. However cases have also been confirmed in Whanganui, Taranaki, Reporoa and Rangiora.
A further increase has been seen in the last month, with a total of 129 farms so far affected. It is believed that this increase may be related to the drought and higher winter temperatures increasing the survival rates of the ticks that transmit the infection.
Further information is available on the MPI website and DairyNZ website
