April 27, 2022


Research offers novel approach to controlling Africa's East Coast fever in cattle



Researchers from the International Livestock Research Institute (ILRI) in Kenya and the Roslin Institute at the University of Edinburgh in Scotland have discovered a genetic marker that can predict accurately if an individual cattle can survive an East Coast fever infection, which could result in breeding programmes that may improve millions of African smallholder farmers' livelihoods, Phys.org reported.


East Coast fever is a serious problem in the African continent. It is caused by the parasite Theileria parva, which is spread by ticks. In the 13 African nations where it is prevalent, it kills a million animals annually, or one cow every 30 seconds. Smallholder farmers' livelihoods can be destroyed by these losses, which cost an estimated US$300 million each year.


Phil Toye from ILRI said because this disease does not affect wealthy nations, funding for East Coast fever research has been limited.


There is an East Coast fever vaccination that offers cattle lifetime immunity. But production takes a long time and costs 10 to 20 times more than other conventional animal vaccinations. Producing the vaccine involves crushing up hundreds of thousands of infected ticks in an industrial blender.


The second alternative is to dip livestock in acaricides on a regular basis, which are tick-killing pesticides. But this process is time-consuming, polluting, and in certain areas, farmers must dip their cows more than once a week.


David Wragg from Roslin, Annie Cook from ILRI, and other team members studied the DNA from this one resilient bovine family in the context of clinical data from field investigations and discovered a genetic signature that signals resistance for East Coast fever in a new research published in PLOS Genetics.


The allele they found may or may not be the gene that controls the development of the animal's cells when it is infected with the parasite, protecting it from disease.


Wragg said it doesn't matter for breeding, as all that is required is a mechanism to say, 'this animal an excellent to breed from because its kids will probably survive the sickness. Only one out of every 20 mice with two copies of the allele succumbed to the illness in tests, indicating that the marker is quite effective.


However, more studies into the particular gene (or genes) responsible and their mode of action might lead to scientists editing cattle's DNA to make them disease resistant. This opens the door to more readily raising highly productive European or cross-bred animals in regions of Africa where East Coast fever is prevalent, potentially increasing the quantity of milk and meat produced on the continent substantially.


More study is also needed to guarantee that tolerance to the illness has no unintended consequences—for example, tolerance to malaria in people is linked to sickle-cell anaemia, which causes various health issues.


Toye said learning more about the genetic mechanism could aid in the advancement of human leukaemia research.


-      Phys.org