First study on birds as hosts of Lyme Disease
Researchers at the University of Coimbra in Portugal lead the first study on the role of birds as reservoir hosts of the bacterium that causes Lyme borreliosis. The blackbird is a major reservoir host of the bacterium Borrelia burgdorferi s.l., responsible for Lyme disease - a disease that, if not treated at an early stage, causes severe lesions in the neurological, dermatological and articular systems.
This is the main conclusion of the first study in Portugal focused on the role of birds as agents for spread of infectious disease and as a reservoir of the bacterium Borrelia burgdorferi s.l., which is maintained in nature by various groups of vertebrates, including birds and some species of mammals and reptiles. This bacterium is transmitted by ticks, especially Ixodes ricinus.
Funded by the Foundation for Science and Technology (FCT), the study was developed over the past three years by a team of five researchers from the University of Coimbra, Center for the Study of Infectious Disease Vectors and the Dr. Ricardo Jorge National Institute of Health and the University of Neuchâtel (Switzerland).
Lyme disease, whose incidence is particularly high in the temperate regions of the northern hemisphere, was discovered for the first time in Portugal in 1989, and the first case was diagnosed in the region of Évora. Since then, about 35 new cases occur annually.
Although the incidence of disease is low in Portugal, "it is important to be informed about the risk of transmission of this disease and how to prevent it because the diagnosis is difficult due to the fact that early symptoms are similar to other diseases. This research provides valuable information to define the areas of risk and factors that influence the emergence of diseases transmitted by ticks and possibly prevent disease outbreaks", states Cláudia Norte, coordinator of the study, which has already been published in international journals Environmental Microbiology and Experimental Applied Acarology.
Moreover, the researcher continues, "More and more people travel to other countries, including in areas where prevalence is high. Information is essential to take proper care". "Thus", she advises, "The use of light-colored clothes for a walk in the countryside or in the woods, where there are ticks normally, and looking to see if any tick is lodged in the body are a good idea. If so, remove it as soon as possible because the bacterium takes a few hours to pass effectively to a human. After the bite, if the disease is not properly treated with antibiotics at an early stage, bacteria can spread throughout the body and cause serious injury at neurological, cardiac and articular levels".
The study also allowed the identification of a new strain of bacterium in Portugal - B. turdi - comprised by the capture of birds abundant in Portugal (about 20 species) for collecting blood samples and other tissues and ticks which were parasites on these birds. These samples have been evaluated at the molecular level to verify that they were infected with the bacterium Borrelia burgdorferi s.l.
Plants were harvested at Tapada de Mafra and Mata do Choupal, monthly, for one year to assess seasonal variations in the abundance, distribution and infestation of ticks. With this approach, the researchers obtained information on what types of birds contribute most to the maintenance of different species of ticks and of course to the pathogens that may be carried.
Cristina Pinto
University of Coimbra
