CD40LG and infectious disease: In addition to the highest density of people in Touba during the Magal event, which is known to be a risk factor of an increased number of cases during an infectious disease outbreak [23], the observed difference can be linked to the fact that, in contrast to this study, during the Louga outbreak only molecular testing of suspected DENV cases was used, leading to a probable underestimation of real number of cases by missing IgM positive cases.