The World Health Organization (WHO) has clearly stated that there is no systematic connection between migration and the importation of infectious diseases, as opposed to widely-held perceptions to the contrary.
Of course, this does not mean that refugees cannot get or be sick. Infectious diseases are widespread. Refugees have long, exhausting journeys behind them; clean water and food and opportunities to wash themselves or their clothes are rare in such circumstances. Cramped conditions during refugee treks and in refugee reception centres favour the transmission of pathogens.
Viruses that cause respiratory diseases are widespread in Austria, and flu epidemics and common colds occur every year – refugees represent no additional risk to the population. On the contrary: the refugees themselves have a higher risk of becoming infected in Austria as a result of their physical and psychological exhaustion.
Diseases caused by food or polluted water usually cause diarrhoea, often accompanied by nausea, sickness and fever. The most common pathogens that cause this are salmonella and campylobacter; bacterial diarrhoeal diseases that are uncommon here -- such as the dysentery pathogen (shigella) or typhus (salmonella typhi) -- can also be found among refugees.
The danger that refugees could bring exotic viruses -- such as Ebola, Crimean-Congo haemorrhagic fever, lasse virus, or the Middle East respiratory syndrome coronavirus -- to Austria is very low: experience has shown that the occasional importation of such diseases takes place via regular travellers, tourists or people working in the health sector.
In short: the risk of infection through normal contact with refugees is not significantly higher than the risk we take when meeting a great number of people, in general: e.g. on public transport or at the football stadium. Basically, the following applies: washing the hands with soap reduces the risk of an infection for oneself and others.
A so-called “syndrome-based surveillance” was put in place to get a rapid overview of the health situation in refugee centres. This cumbersome term denotes a rather simple surveillance system which helps recognise if there is an accumulation of similar disease symptoms. This helps doctors and health personnel initiate the appropriate measures to prevent diseases from spreading.
WHO: Frequently asked questions on the topic of Migration and Health
Federal Ministry of Health: Frequently asked questions about migration and health
(only available in German)