Week 2 Infectious Disease Epidemiology

What is Epidemiology? 

The study and analysis of the incidence, distribution and control of diseases  

What is disease epidemiology? 

* Deals with one population e.g humans  
* Risk is a case  
* Identifies causes  
* E.g cancer (radiation source)

What is infectious disease epidemiology? 

* Two or more populations e.g human and pathogen  
* A case is a risk factor  
* The cause is often known  

Give examples of two or more populations in infectious disease epidemiology 

* Humans  
* Infectious agents: Helminths, bacteria, fungi, protozoa, viruses, prions  
* Vectors: Mosquito (protozoa-malaria), Snails (helminths-schistosomiasis), Blackfly (microfilaria-onchocerciasis) 
* Animals: Dogs and sheep/goats : Echinococcus, Mice and Ticks: Borrelia 

What is infectious disease epidemiology used for? 

* Identification of causes of new, emerging infections, e,g HIV, vCJD, Zika, SARS-CoV2 
* Surveillance of infectious disease  
* Identification of source of outbreaks  
* Studies of routes of transmission and natural history of infections 
* Identification of new interventions 

What is an infectious disease caused by? 

infectious agent  

What is communicable diseases caused by? 

Transmission directly or indirectly from an infected person  

What is a Transmissible disease caused by? 

Transmission through unnatural routes from an infected person 

Give examples of routes of direct transmission  

* Skin-skin: Herpes type 1  
* Mucous-mucous: STIs  
* Across placenta: toxoplasmosis  
* Through breast milk: HIV  
* Sneeze-cough: Influenza

Give examples of routes of indirect transmission 

Food-borne: salmonella  

Water-borne: Hepatitis A  

Vector-borne: Malaria  

Air-borne: Chickenpox  

What are 3 types of modes of disease transmission? 

Contact transmission  

Vehicle transmission  

Vector Transmission