We prove a combination theorem for trees of (strongly) relatively hyperbolic spaces and finite graphs of (strongly) relatively hyperbolic groups. This gives a geometric extension of Bestvina and Feighn's Combination Theorem for hyperbolic groups.

The emergence of deadly viruses is one the epitomes major global health threats. Currently world going through COVID-19 pandemic resulting in extreme morbidity and mortality, which caused by severe acute respiratory coronavirus 2 (SARS-CoV-2). Besides, SARS-CoV-2, recent perturbation chikungunya virus (CHIKV) infection, dengue (DENV), zika (ZIKV) etc. are worth being noted. Although an array re...