Factors influencing the occurrence of infectious disease outbreaks in Lebanon since the Syrian crisis.

Since the beginning of the Syrian crisis in 2011, the region has witnessed a major population displacement. Lebanon, a country with a population of 4.2 million, has welcomed around one million refugees. A rise in the incidence of Measles, Hepatitis A and Leishmaniosis was noted. This paper aims to document the incidence of outbreaks along with the factors that contributed to their emergence in Lebanon. A comprehensive literature review was conducted using electronic databases and (non) governmental reports, including studies reporting the state of Syrian refugees in Lebanon and those reporting on infectious outbreaks in Lebanon and Syria. Primary outcomes were defined as incidence or prevalence of Measles, Hepatitis A, and Leishmaniosis in both populations. Secondary outcomes were set to be the risk factors for the outbreaks. As of February 2016, Lebanon registered a total of 1.067.785 refugees. Infectious outbreaks were reported in Lebanon just after initiation of Syrian migration, with 1760 new measles cases, 1551 hepatitis A cases, and 1033 Leishmania cases in 2013. Local factors probably contributing to the emergence and dissemination of the outbreaks include living conditions, water and sanitation, nutritional state, and immunization. The outbreaks were not only reported in regions with higher refugee concentration, but also within other Lebanese regions. This was attributed to deficiencies in immunization of measles, low socioeconomic status and poor living conditions. The Syrian crisis has led to considerable impact on the demographic, economic, and political systems in Lebanon, next to an important burden on the healthcare system.