Tick-borne diseases pose a serious problem to the international trade of animals and constitute a major constraint to increased productivity of livestock. Current disease management control consists of the use of tick-specific pesticides known as acaricides. However, a number of drawbacks are associated with their use such as cost, resistance, and environmental and food safety. To address these issues, the EU-funded project Epigenevac focused on ruminant infections caused by Ehrlichia ruminantium (cowdriosis or heartwater) and Anaplasma marginale (anaplasmosis). Cowdriosis occurs in sub-Saharan Africa, Madagascar and the surrounding islands while anaplasmosis has a wider distribution. They are both transmitted by various species of ticks or biting flies. Project partners wished to develop specific diagnostic tests and efficient vaccines to control the emergence and spread of these bacterial diseases. As a first step, scientists sequenced the genomes of E.ruminantium and A.marginale and by combining the data with RNA and protein information, they aimed to identify potential antigens that could be used to design vaccines. The most promising candidate genes were cloned in various delivery systems and improved immunological screening methods were developed in order to test the potential vaccines. Subsequently, a large field study on the epidemiology of cowdriosis and anaplasmosis was conducted to provide regional maps of diseases and study the dynamics of tick-vector-host interactions. Molecular methods were developed for the sensitive detection and genetic characterisation of E.ruminantium and A.marginale. Epigenevac thus provided essential knowledge on the genetics of bacteria-causing ruminant infections and identified antigens which could be utilised for immunisation strategies. The diagnostic tests optimised during the project will act as quantitative indicators to help decision making in animal health interventions.
Epidemiology and new generation vaccines for Ehrlichia and anaplasma infections of ruminants
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30 April 2020