There are several bugs that can cause harm or discomfort to humans but there are some insects that can be fatal.  The usual cause of death is disease carried by the bug but that is not always the case.

The Kissing bug, or hemiptera, often feed on other animals blood.  These insects carry a disease known as Chagas Disease.  Chagas Disease can be fatal if not treated.

African ants can be dangerous.  They have been known to attack humans if hungry.  This insect doesn’t carry any deadly diseases.  The usual cause of death due to these animals is asphyxiation.

Tse Tse Flies carry a disease known as trypanosomiases.  This disease is fatal to humans. These flies kill several hundred humans in Africa every year.