infectious disease;  infection
 infection route;  source of infection
 infection through contact
 mass infection;  infection outbreak;  infection cluster
 explosive growth of infections;  explosion of cases of an infection
 hospital-acquired infection;  healthcare-associated infection;  HCAI;  nosocomial infection
 infection prevention;  disease control
 oral infection;  orally transmitted infection
 respiratory tract infection;  RTI
 infection route;  transmission route
 susceptibility to infection;  lack of resistance to infection
 macro infection type virus
 respiratory tract infection;  RTI
 asymptomatic spread (of an infectious disease);  silent infection;  subclinical infection
 community-acquired infection
 human-to-human transmission (of a disease)
 breakthrough infection (infection in someone who is vaccinated)