Infectious diseases transmitted at work are frequent globally. Lung infections due to exposure at work are mainly affecting two broad groups, health care workers (HCW) and people exposed occasionally to sick animals. The main challenge globally during the last decades has been tuberculosis (TB), different influenza strains and coronaviruses. TB is still a global threat infecting almost 9 mill people world-wide and causing 1, 4 mill deaths (2011). Influenza is common during winters in smaller epidemics, but has also caused serious pandemics (1918, 1957, 1968 and 2009). TB in miners is a major health problem in South-Africa. Avian influenza is caused by the influenza A strain in birds. Humans may acquire avian influenza by inhalations of droplets or by contact from infected material. Different avian strains have been shown to infect humans (H5N1, H7N7 and H9N2 strains). Swine influenza H1N1 (S-OIV) were reported from Mexico in 2009 with a further rapid spread to other countries and causing a pandemic. The syndrome of SARS caused by a coronavirus (SARS-CoV) was first described in Guangdong, China in 2002. The infection spread rapidly and 29 countries were affected in the first epidemic in 2002-3. In 2012 a novel coronavirus (MERS-CoV) related to SARS was described in a Saudi Arabian patient who died of pneumonia and multi-organ failure (Middle East Respiratory Syndrome - MERS). Other occupational respiratory infections are also encountered, among them legionella, psittacosis and Q-fever. Increased mortality of pneumonia in welders is a special problem, probably due to reduced resistance to infection because of welding fumes.
Knowledge of disease transmission mechanisms is necessary for managing epidemics.