Final answer:
Children under age 5 and pregnant women are the primary groups at high risk from malaria, specifically the deadly P. falciparum strain, which accounts for a significant number of annual deaths in affected regions, predominantly in Africa and Asia.
Step-by-step explanation:
Malaria is an infectious disease caused by a protozoan parasite called Plasmodium, which is transmitted to humans through the bite of infected Anopheles mosquitoes. The most lethal cause of malaria is P. falciparum, predominantly found in Africa and Asia, and while there are treatments available, the disease poses a serious risk to certain groups. The primary groups at risk of dying from malaria when it is left untreated include children under age 5, who suffer from high mortality rates, and pregnant women, who can experience severe anemia, fetal loss, and maternal death. Middle-aged carpenters, football players, and men living in igloos are not specifically identified as high-risk groups for malaria, which is more common in tropical and subtropical climates. It is critical for global health initiatives to focus on preventive measures, treatments, as well as the possibility of a vaccine for malaria, which poses ongoing threats to millions worldwide.