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Whole genome profiling of
Theileria parva isolates
East Coast Fever (ECF) is a fatal bovine lympho-proliferative
disease endemic in sub-Saharan Africa. Twenty-eight million
cattle are at risk of contracting the disease. It results in
the death of at least one million cattle, causing economic
losses of about 200 million dollars annually. In sub-Saharan
Africa, the disease is primarily controlled by the use of
chemical acaricides. However, this is becoming unsustainable
due to high costs, increasing risks of emergence of acaricide-resistant
tick strains, and the retention of toxic residues
of the chemicals in meat, milk and the environment.
The infection and treatment method (ITM) of immunisation
is a medium-term sustainable method increasingly
being adopted by farmers in East, Central and Southern
Africa. It involves inoculation of cattle with a near-lethal
dose of live sporozoites of Theileria parva – the causative
agent of ECF – along with a high dose of oxytetracycline to
control the infection. One mixture of T. parva stocks that
is increasingly used by local farmers is the Muguga cocktail.
It comprises three stocks of T. parva: Muguga, Kiambu 5 and
Serengeti-transformed. In this project, we will sequence
the whole genomes of eight strains of T. parva, including
the components of the Muguga cocktail and two buffaloderived
strains, using the high throughput 454 sequencing
technology.
So far, the focus of the project has been on sequencing
material preparation. Genomic DNA of T. parva Uganda,
Marikebuni and Uganda/Muguga recombinant have been
derived successfully and are being sequenced. Samples for
the T. parva Kiambu-5 isolate are being prepared at ILRI.
The genome of the Serengeti-transformed isolate has
recently been sequenced by the 454 method using a combination
of paired-end and shotgun libraries. It has been
assembled into 32 contigs using the published T. parva
Muguga genome as a template. Annotation against
T. parva Muguga genome using sequence comparison
methods such as BLAST algorithms 1 is underway.
After sequencing Kiambu-5, we will compare the three vaccine
components in order to gain insight into the genes
that might contribute towards the efficiency of the ITM.
From the sequences we will identify (i) highly conserved
and rapidly evolving genes, (ii) genes under positive selection
that would relate to host-parasite interactions, and
(iii) SNPs for micro-epidemiological studies. The genome
sequences of the other parasite isolates will enable us to
study evolutionary forces driving parasite diversity also on
the level of sexual recombination.
1 Basic Local Alignment Search Tool algorithms
Research fellow
Sonal Patel, ILRI, Kenya
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Supervisors
Claudia Daubenberger, STI, Switzerland;
Richard Bishop, ILRI, Kenya
Collaborators
Weihong Qi, University of Zurich, Switzerland;
Etienne de Villiers, ILRI, Kenya
Duration
August 2009 – July 2012
Capacity development
Research fellowships
The infection and treatment method vaccine
being administered to a pastoralist‘s calf