text: Travel to endemic areas is a risk factor for<unk> . For travelers, regions associated with the highest estimated relative risk of infection are West Africa and Oceania.  Human behavior, often dictated by socioeconomic situations, can influence the risk of<unk>  for individuals and communities.  In addition, children and pregnant women are at a higher risk of contracting<unk> .  Certain biologic characteristics can protect against particular types of<unk> . Two genetic factors, the sickle cell trait and absence of Duffy blood group, have been shown to be epidemiologically significant.
option_0: Malaria risk factors
option_1: Dengue fever risk factors
option_2: Ebola risk factors
option_3: Filariasis risk factors
option_4: Lassa fever risk factors
option_5: Influenza risk factors
option_6: Leptospirosis risk factors
option_7: Hantavirus infection risk factors