Footrot is a highly contagious disease of ruminants such as sheep, goats and cattle that has significant economic impact in sheep farming countries, such as New Zealand, that have a temperate climate and moderate to high rainfall.
The disease is responsible for causing losses in body weight and wool growth in affected animals and makes them susceptible to other infectious diseases. In addition, farmers incur increased treatment and control costs.
On-going footrot research in the Agriculture and Life Sciences Division at Lincoln University aimed at characterising the causative agent of footrot has involved growing bacteria from thousands of footrot samples taken from four different farming regions in New Zealand.
Tulay Catagay, a PhD candidate working under the supervision of Dr Jon Hickford, has been working on a new method of identifying footrot as one small part of her research. She has developed a robust method that will make the detection and identification of footrot faster and more reliable. In addition, Tulay has also revealed findings that describe how the virulence of the disease may change.
Using molecular biology techniques Tulay identified the DNA sequence for six new strains of the footrot bacterium (in addition to the eleven already identified by researchers at Lincoln University). These six new gene sequences are different from all previously reported strains of the bacterium (called Dichelobacter nodosus or D. nodosus for short).
“Studying this disease was quite a challenge,” said Tulay, “because the bacterium causing footrot can only grow when there is no oxygen present. It’s called a fastidious anaerobe.
“This meant that I had to take special care when I was growing these bacteria in the laboratory or they just curled up and died.
“I’m very grateful for all the help I received from the farmers who let me sample their sheep.”
Tulay also had to separate the footrot bacterium from the large number of other bacteria present in a footrot lesion. These other bacteria are involved in the initiation of the disease and not active in the disease itself.
Traditionally, the identification of the bacterium has relied on the isolation of the bacterium from footrot lesion material and then microbiological and biochemical tests are used to identify the bacterium. All these techniques are expensive and take a lot of time,
Tulay’s work using molecular techniques is based on a particular gene in the footrot bacterium and can be used for the detection, identification and serotyping of D. nodosus colonies, and much more rapidly than using more traditional methods.
This work was funded by Lincoln University and the Foundation for Research, Science and Technology.
FOR FURTHER INFORMATION CONTACT
Janette Busch, Technical Writer
Lincoln University, Canterbury
Tel: 64 3 325 2811 ext 8114
Email: Janette Busch