What factor is most responsible for both the very young and the very old being most susceptible to infectious diseases?  

  The organism shown in the figure below is a(n)  

  Many enteric pathogens are transmitted through  

  Protozoans use all the following mechanisms to avoid the host immune system EXCEPT  

  __________ is an antimicrobial substance found in tears that can cleave the bacterial cell wall.  

  Transplacental transmission is an example of__________transmission.  

  In viruses such as influenza, the ability to undergo a major genetic alteration is called antigenic  

Fungi are eukaryotic like our cells.  An anti-fungal drug could be selective for fungal infections by 

  Which stage of an infectious disease does number 3 represent?  

  A CD4+ T-cell count lower than 200 cells/μl is defined as ______.