VHF: Diversity of viruses and animal vectors involved in disease transmission

Viral Hemorrhagic Fevers (VHFs) comprise a group of severe illnesses characterized by fever and bleeding disorders, caused by diverse viruses from distinct families such as Filoviridae (e.g., Ebola and Marburg), Arenaviridae (e.g., Lassa and Junín), and Nairoviridae (e.g., Crimean-Congo Hemorrhagic Fever), among others. These viruses are well-known for initiating outbreaks, particularly in areas with limited resources. Outbreaks are often intensified by close human-to-human contact, predominantly in healthcare environments. Nosocomial transmission can significantly escalate these outbreaks, especially when diagnostic confirmation is delayed. As a result, healthcare facilities in resource-poor areas may struggle with inadequate infection control measures, personal protective equipment, and isolation facilities, increasing the risk of spreading infection among patients, visitors, and healthcare staff. This chapter explores the diversity and classification of VHF viruses, their transmission through animal and arthropod vectors, and the ecological and geographical factors that affect their spread. It discusses the challenges of managing VHFs due to their high genetic diversity and the environmental changes that influence vector behavior and virus-host interactions. It advocates for an interdisciplinary approach that merges insights from virology, ecology, and public health to improve surveillance, diagnostics and responses to outbreaks, particularly in under-resourced settings. And finally, considers the difficulties in developing vaccines, highlighted by the unpredictable nature of outbreaks and the genetic variability of the viruses, underscoring the importance of global cooperation and public health innovation. This perspective aims to enhance preparedness and effective management of future outbreaks, thus bolstering global health security.