Infectious diseases | Human Health & Diseases

infectious disease are communicable/transmittable;
pathogens spread from infected to uninfected people;
some people have the disease but do not show an symptoms/are carriers;
makes tracing very difficult;
many developing countries struggle to pay health personnel;
and to carry out effective prevention and treatment programmes;
problem of development of clean water supply;
good sanitation difficult to achieve;
natural disaster/wars/civil unrest;
growth of shanty towns;
rural areas not reached;
many developing countries in warmer regions where pathogens/parasites/insects/vectors thrive;