Migrants crossing Europe are facing worsening conditions after snow blanketed large parts of the Balkans. <br />Aid centres have been organised along borders to help the migrants as they attempt to make their way to their final destination. <br />Medical charities say most patients are suffering with respiratory problems such as bronchitis and flu. <br />BBC News spent an evening in a Red Cross centre on the Macedonian-Serbian border to watch a team of young medics at work.
