Transmission of Diseases Flashcards
What must a pathogen be able to do?
- A pathogen must be able to travel from one host to another, get into the host’s tissues, reproduce, and cause damage to the host.
What are the most common forms of transmission?
Through a vector, physical contact, droplet infection.
What causes malaria?
- Eukaryotic Plasmodium falciparum, P. vivax, P. malariae cause malaria.
What is the cycle in which parasites are transmitted?
Infected host – mosquito sucks parasites into its stomach.
Gametes fuse, and zygote develops in stomach.
Infective stages formed, passing to the salivary gland.
Mosquito bites another person; injecting saliva as anti-coagulant, which contains infective parasite.
In human infective stages enter the liver, multiply, before passing into the blood.
Enter RBC where gametes are produced.
Malaria can be spread by the human immunodeficiency virus. Enters body and remains inactive (HIV-positive) – becomes active, destroying T-h cells –resulting in an inability to fight infections effectively. Contract opportunistic infections. AIDS = Acquired immune deficiency syndrome.
How can HIV be contracted?
body fluid exchanged, unprotected sex, unscreened blood transfusions, unsterilized surgical equipment, hypodermic needle sharing, needle-stick, across placenta, breast feeding.
What is TB caused by?
- TB caused by Mycobacterium tuberculosis and M. bovis. Usually found in the lungs. Contracted by droplet infection. Bacteria contained in tiny droplets of liquid.
When is TB more likely to be spread?
TB is more likely to spread when: overcrowding, poor ventilation, poor health, poor diet, homelessness. TB can be contracted from milk/meat of cattle.
