Environmental DNA detection as evaluation of tuberculosis risk factors for cattle in multi-host settings

The control and eradication of animal Tuberculosis continues to be a challenge when several domestic and wild hosts contribute to the maintenance of the Mycobacterium tuberculosis complex. In the last year, researchers have been focused in understanding this multi-host system in order to generate knowledge and tools aimed at fighting tuberculosis in the domestic and wild interface. In this context, environmental DNA detection belonging to Mycobacterium tuberculosis complex is an effective test for epidemiological diagnosis.

Nowadays, animal tuberculosis (TB) is the main concern for cattle farmers in Spain and others member States of the European Union (EU). TB is a zoonotic disease and it is caused for the infection by a large number of mycobacterial species including in Mycobacterium Tuberculosis Complex (MTC). In the EU there is a control and eradication program for TB. Because of these, cattle herds are subject to TB test to evaluate the presence of the pathogen in the flock. For that matter, movement restrictions are imposed on positive herds.

In the last years, eradications programs have included some domestic and wild species that can maintenance MTC in a multi-host system. Proof of that are the different regional eradications programs of TB in goats flock or the implementation of barriers and others measures to prevent contact (direct and indirect) between cattle and other domestic and wild species.

Currently, we want to go further with our investigations and we are focus in the study of the environment as an actor in the multi-host system of TB. A recent study shows environmental DNA belonging to MTC detection as an effective tool in the control of TB. The study titled “Environmental DNA points at shared pastures and proximity to woodlands as tuberculosis risk factors for cattle in multi-host settings” has been made by research belonging to IREC, Sabiotec and others research centres.

After studying different environmental and farm-dependent variables, environmental samples positive to MTC-DNA are correlated with some variables (altitude, distance to forest or use of communal pastures) that allow contact with wildlife. In that sense, this study suggests that environmental DNA sampling can help in assessing contact risk with MTC in livestock, at the herd level. In other words, with environmental DNA we can evaluate the possibility that our herd will be positive in future official TB tests

 “With environmental DNA we can evaluate the possibility that our herd will be positive in future official TB tests”

 Environmental DNA detection is an epidemiological diagnosis, which allows us to understand the dynamic of the disease in the study area provides information at the herd level (never at the individual level). Environmental DNA has a particular interest in hotspots. Hotspots are focal points where TB becomes recurrent and difficult to eradicate. The area affected by a hotspot can be a farm, region, county, or state.

In summary, environmental DNA analysis enables us to expand and deepen in the epidemiological diagnosis of TB. This helps us to implement an effective biosecurity protocol for the farm. Biosecurity programs joined the official sanitation campaigns improve the health status of our farm. The advantage of study environmental DNA is that the information obtained allows us to act between official tests.

If you want to know more about the biosecurity and environmental DNA studies that we carry out at Sabiotec, contact whit us. Presently, Sabiotec leads ESTUGA project. The objective of this project is to develop a system based on sponges that allows the incorporation of the detection of environmental DNA in Tb Control and Eradication Programs.

ESTUGA Project has been funded by the regional government of Castilla-La Mancha (Spain) thought call for projects “Innova-Adelante”, co-financed (80%) by European Social Fund (ESF) of European Union (EU). This project aims to boost I+D+I activity, improve productivity and competitiveness, and promote the transfer of knowledge.

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