Describe the two classic patterns of propagation of infection in a population? How would you prevent the propagation of infection occurring with these two patterns?

Pathogens have a variety of traits that interact with a host and enable the pathogen to enter a host, adhere to host cells, gain access to nutrients, and escape detection or removal by the immune system. These traits are called virulence factors. The following enzymes and toxin can act as virulence factors and contribute to bacteria’s pathogenicity. What are the specific actions of the following enzymes and toxin that make them virulence factors? Coagulase Kinase (such as staphylokinases and streptokinases) Hyaluronidase Collagenase Cytotoxin

Please define, explain, and discuss the concept of the “global burden of disease”? How do you measure the burden of disease? \What is the global burden of COVID 19?

Suppose you are designing a study to determine whether a vaccine is effective. You recruit volunteers and then assign them into two groups. Which of the following is a better way to determine if the vaccine works in a wide variety of people? (a) Recruit people from a variety of backgrounds: different ethnicities, ages, sexes, etc... and then randomly form two groups. (b) Recruit people for the study who are very similar to one another, such as married nonsmoker female nurses in their forties who don't drink with no health problems and good incomes, then randomly form two groups