Specific Infectious Diseases of Public Health Concern

Escherichia coli (E. coli) is a bacterium commonly found in the gut. Some strains can cause serious food poisoning, leading to diarrhoea and sometimes to life-threatening complications including haemolytic uraemic syndrome (WHO, 2018a). 

Avian influenza is an infectious disease of birds caused by type A influenza viruses of the Orthomyxoviridae family. Naturally occurring among wild bird populations, avian influenza viruses can infect domestic poultry and other bird species. Some avian influenza viruses can also infect mammals and those affecting humans are called zoonotic. A pandemic can occur when a novel influenza virus spreads in human populations worldwide (adapted from FAO, 2009; WHO, 2023a; 2023b; WOAH, no date).

Pertussis is a highly contagious disease, which can be fatal, of the respiratory tract caused by the bacterium Bordetella pertussis (WHO, no date a).

Hepatitis C is a blood-borne liver disease caused by the hepatitis C virus: the virus can cause both acute and chronic hepatitis, ranging in severity from a mild illness lasting a few weeks to a serious, lifelong illness including liver cirrhosis and liver cancer. Hepatitis C is endemic and epidemic worldwide (WHO, 2024a).

Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by Middle East respiratory syndrome coronavirus (MERS‐CoV) with a clinical spectrum of infection ranging from no symptoms (asymptomatic) or mild respiratory symptoms to severe acute respiratory disease and death (adapted from WHO, 2022).

Pandemic influenza is the worldwide spread of a new influenza virus to which there is little or no pre-existing immunity in the human population (WHO, 2019). 

Polio (human) is a highly infectious viral disease, which mainly affects young children, where 1 in 200 leads to irreversible paralysis and among those paralysed, 5–10% die when their breathing muscles become immobilized (WHO, 2025).

Human immunodeficiency virus (HIV) is a virus that attacks the body’s immune system. Acquired immunodeficiency syndrome (AIDS) occurs at the most advanced stage of infection. HIV targets the body’s white blood cells, weakening the immune system. This makes it easier to get sick with diseases like tuberculosis, infections and some cancers. HIV is spread from the body fluids of an infected person, including blood, breast milk, semen and vaginal fluids. WHO now defines Advanced HIV Disease (AHD) as CD4 cell count less than 200 cells/mm3 or WHO stage 3 or 4 in adults and adolescents.

Mpox, previously known as monkeypox, is a viral illness caused by the monkeypox virus, a species of the genus Orthopoxvirus. There are two distinct clades of the virus: clade I (with subclades Ia and Ib) and clade II (with subclades IIa and IIb). Mpox can be fatal in some cases (adapted from WHO, 2024).

Seasonal influenza is an acute respiratory infection caused by influenza viruses which circulate in all parts of the world with around a billion cases of seasonal influenza annually, including 3–5 million cases of severe illness. It causes 290,000 to 650,000 respiratory deaths annually (adapted from WHO, 2025).