**5. Biological risk factors**

## **5.1. Agents transmitted by respiration and droplets**

Some agents such as droplets and droplet cores can be transmitted via respiratory secretions of patients. Tuberculosis, measles, rubella, chicken pox, *severe acute respiratory syndrome* (SARS), influenza, meningococcal and pneumococcal infections transmit in this way [10, 13]. According to the various studies performed in Turkey, it has been detected that health professionals, par‐ ticularly nurses, are under the risk particularly those working in pulmonary disease services [24, 25]. Demir et al. have performed a study in order to determine the tuberculosis infection risk among health professionals working in pulmonary disease hospital and another hospital which does not have pulmonary disease clinic. They have shown that the tuberculosis infec‐ tion risk was 7.4 times higher in pulmonary disease hospital compared to the other hospital without pulmonary disease clinic because of the higher tuberculosis exposure [26].

#### **5.2. Infections transmitted through direct contact**

These infectious agents transmit through direct contact with the patient. There is no need to be in contact with the skin or mucosa as well as the loss of skin integrity for the transmission. Resistant bacteria and skin parasites such as scabies are examples of microorganisms which can lead to severe infections in inpatients [24].

#### **5.3. Biological agents transmitted by blood and bloody body fluids**

These biological agents can transmit through the skin due to its impaired integrity and mucous membranes (mouth, eye and urogenital mucosa) as a result of the exposure to blood and/or bloody body fluids and some sterile body fluids. Even though there are almost 30 microorganisms which can be transmitted in this way, the most important ones are hepa‐ titis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV) and human immu‐ nodeficiency virus (HIV) since they can lead to systemic infections because of their current importance. The diversity of the clinical outcomes of these agents varies from asymptomatic infections to severe and even fatal infections [3, 4, 12, 13, 24, 27, 28]. The transmission of the infections via blood occurs mostly by the penetration of the needles used in patients, injury with contaminated sharp instruments or mucosal splashes infected blood or body fluids [29, 30]. It has been specified that the two‐third of the health professionals stated that they were exposed to blood and/or body fluids at least once, the HIV infection was related to the profes‐ sion in the 57% of the HIV‐positive health professionals, and the risk of developing hepatitis B infection in health professionals is 10 times more compared to the general population [12, 13]. For example, in Turkey, you can see the Crimean‐Congo Hemorrhagic Fever (CCHF) and Margburg which make hemorrhagic fever and which are infected with blood.
