13 - Infectious disease

Abstract

Infectious diseases remain a major contributor to the global burden of ill health, particularly at the extremes of age. Lower respiratory tract infections accounted for more than 2 million deaths in 2019. Major infectious causes of ill health cause millions of infections worldwide each year. Malaria, for example, accounted for an estimated 228 million infections in 2018. In the Global South malaria and parasitic infections, arthropod-borne viral infections, HIV, respiratory tract infections including tuberculosis and diarrhoeal illnesses are major causes of disease. In the rest of the world community-acquired viral and bacterial infections are complemented by hospital-acquired infections. The pattern of susceptibility to infection is influenced by age, travel history, levels of immune function and specific behaviour, such as people who inject drugs. Fever is a key clinical sign used in the diagnosis of infection and initial clues from the history and examination, along with patient risk factors guide the selection of initial diagnostic tests. Increasing rates of antimicrobial resistance challenge the management of many infectious diseases while the emergence of COVID-19 highlights the susceptibility of human populations to emerging pandemics of infectious disease.