Infectious Diseases

Sexually transmitted infections are transmitted through sexual contact, including vaginal, anal and oral sex and some can also be transmitted from mother-to-child during pregnancy, childbirth and breastfeeding (WHO, 2024).  

Neglected tropical diseases (NTDs) are a diverse group of conditions caused by a variety of pathogens (including viruses, bacteria, parasites, fungi and toxins) and associated with devastating health, social and economic consequences. NTDs are mainly prevalent among impoverished communities in tropical areas, although some have a much larger geographical distribution. (WHO, no date a).  

Vaccine-preventable diseases are those infectious diseases that can be prevented by vaccination (WHO, 2019). 

Vector-borne diseases encompass a variety of illnesses that are caused by the spread of pathogens by living organisms known as vectors. These infectious diseases can be transmitted via vectors among humans (e.g. malaria, dengue), among animals (e.g. African swine fever, East Coast fever), or from animals to humans (e.g. Nipah virus disease). Many of these vectors are bloodsucking insects, and mosquitoes are the best-known disease vectors.

Viral haemorrhagic fevers include a spectrum of relatively mild to severe life-threatening diseases characterized by sudden onset of muscle and joint pain, fever, bleeding and shock from loss of blood. In severe cases, one of the most prominent symptoms is bleeding, or haemorrhaging, from orifices and internal organs (WHO, no date a). 

Zoonotic diseases, or zoonoses, are diseases shared between animals – including livestock, wildlife, and pets – and people. They can pose serious risks to both animal and human health and may have far-reaching impacts on economies and livelihoods and represent a major public health problem. Zoonotic diseases are commonly spread at the human-animal-environment interface – where people and animals interact with each other in their shared environment (adapted from WHO, FAO, WOAH, 2019 & WHO, 2020). 

Diarrhoeal diseases are infectious diseases, contaminants and other causes of diarrhoea. Diarrhoea is defined as the passage of three or more loose or liquid stools per day, or more frequently than is normal for the individual. Diarrhoeal disease is the third leading cause of death in children 1–59 months of age. It is both preventable and treatable. (WHO, 2024a). 

Airborne transmission of infectious agents refers to the transmission of disease caused by the dissemination of very small droplets that remain infectious when suspended in air over long distances and time, and potentially cause significant morbidity and mortality (adapted from WHO, 2020). 

Cryptosporidium is a microscopic parasite that can live in water, food, soil, or on surfaces that have been contaminated with infected faeces and causes the watery diarrhoeal disease cryptosporidiosis (adapted from CDC 2024 and Peletz et al., 2013).

Bloodborne viruses are viruses transmitted by direct contact with infected blood or other body fluids (adapted from WHO, 2023).