Sexually transmitted diseases are infections transmitted from an infected person to an uninfected person through sexual contact (WHO, no date).

Measles is a highly contagious, serious disease caused by a virus from the paramyxovirus family. Transmission occurs through direct contact, droplet spread, and airborne spread. The virus initially infects the respiratory tract, then spreads throughout the body (WHO 2019).

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, 2020).

Lassa fever is a zoonotic disease associated with acute and potentially fatal haemorrhagic illness caused by Lassa virus. It is associated with epidemics particularly where it is endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria (WHO, 2017).

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 zoonotic avian influenza virus spreads in human populations worldwide (FAO, 2009; WHO, 2018; OIE, 2020).

Foot-and-mouth disease is caused by a virus of the family Picornaviridae, genus Aphthovirus. It is a highly contagious and economically important disease of cloven-hoofed domestic animals (cattle, buffaloes, pigs, sheep, goats) and wild animals (FAO, 2012; OIE, 2018).

Neglected tropical diseases (NTDs) are a diverse group of communicable diseases caused by bacteria, viruses or parasites that prevail in tropical and subtropical conditions (WHO, no date). Twenty diseases and disease groups are addressed in the global roadmap for NTDs 2021–2030 (WHO, 2020).

Meningococcal meningitis is a bacterial form of meningitis, a serious infection of the thin lining that surrounds the brain and spinal cord, that is caused by the bacterium Neisseria meningitidis. Meningococcal meningitis has the potential to cause large-scale epidemics and is observed worldwide (WHO, 2018).

The human immunodeficiency virus (HIV) is a viral sexually transmitted and blood-borne infection which targets the immune system, weakening people’s defences against opportunistic infections and some types of cancer. The most advanced stage of HIV infection is acquired immunodeficiency syndrome (AIDS), which can take from 2 to 15 years to develop if not treated, depending on the individual. AIDS is defined by the development of certain cancers, infections or other severe clinical manifestations (WHO, 2019).

Tuberculosis (TB) is a curable bacterial infectious disease caused by Mycobacterium tuberculosis that most commonly affects the lungs. It causes national epidemics of varied severity worldwide. Forms of TB that are resistant to treatment – multi-drug resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) – are public health crises and threaten health security worldwide (WHO, 2020).