Thread🧵on modes of pathogen transmission. #monkeypox

Transmission is messy, and there is no single mode that pathogens employ to invade a body. Indeed, modes can change.

Plague provides a great example of this: it occurs in multiple forms, depending on transmission route. 1/13

All are caused by the bacterium Yersenia pestis

Bubonic plague occurs when infected fleas bite a person, or the bacteria enter through a break in the skin. Infection causes characteristic "buboes"

Preventative strategy would be flea and rat control. 2/13 https://t.co/xR5gdRuK53

Plague can become more widespread via the bloodstream, causing septicemic plague. This leads to black areas of necrosis in the body, hence the term, "Black Death."

As long as it doesn't get to the lungs, prevention is the same as previous - flea and rodent control. 3/13

However if the bacteria set up infection in the lungs, they can now exit the body via respiratory aerosols

This is now pneumonic plague, a highly contagious form of the disease, transmissible by air, with an incubation period of only 1-3 days & 100% fatal without treatment. 4/13

The infection control measures of flea and rodent control are ineffective against pneumonic plague -- isolation and treatment of cases, airborne precautions, and prophylactic treatment and monitoring of exposed individuals are needed. 5/13