Q1 Causes of infectious disease Flashcards
DOT 1
What is a Bacteria? what types of cell and characteristics and names one example
Prokaryotic, unicellular (No membrane bound organelles).
Found everywhere. can release toxins or damage host tissue. e.g) Salmonellosis, caused be Salmonella enterica –> Vomiting & diarrhoea
What is a Fungi? what types of cell and characteristics and names one example
Eukaryotic, non photosynthetic organism with a cell wall e.g)mushrooms or yeast.
Causes disease through their enzymes. e.g) Athletes foot –> itchiness, inflammation and flaky skin
What is a Protists? what types of cell and characteristics and names one example
Eukaryotic, unicellular microorganism. has cilia and flagella. e.g) malaria, caused by protist plasmodium –> attach to haemoglobin –> fever, nausea
What is a Viruses? what types of cell and characteristics and names one example
Not cellular entities, not living.
Has a single type of nucleic acid (DNA or RNA) encased in a protein coat (capsid). hijacks a host’s cell and steals enzymes and nutrients to reproduce. e.g) Influenza –> influenza virus –> damages lung tissue –> coughing, nasal congestion
What is a Prions? what types of cell and characteristics and names one example
Infectious non cellular proteins (abnormally folded versions of proteins) –> capable of causing degenerative diseases in the nervous system. No genetic material (DNA or RNA). e.g) Kuru –> spread spread through cannibalism, prion found in the contaminated brain tissue –> results in progressive & fatal brain disease.
What is a Macroscopic Parasites? what types of cell and characteristics and names one example
Multicellular pathogens. seen with naked eye. causes disease through competing with nutrient from the host. produce toxins–> damages host tissue. e.g) Ticks.
can be either Ectoparasites (live outside body) or Endoparasites (live inside body)
What is Direct contact as a way of transmission? give examples of the way its transmitted and disease it can transmit
Physical contact between host and non-infected organism. e.g) through touching kissing or biting contact with body fluids prenatal. e.g) of disease is Ebola, which is spread by direct contact with blood or other body fluids of an infected person
What is Indirect contact as a way of transmission? give examples of the way its transmitted and disease it can transmit
Reservoir is created outside of the host that allows pathogens to stay alive. e.g) through airborne transmission (droplets coughing or sneezing touching infected surfaces), contaminated food/water, vectors.
Vehicle Transmission - spread of pathogens by contaminated air, food or water e.g) flies that physically transfer pathogens
Vector Transmission - involves animals that assist in the transmission of a pathogen e.g) Mosquitos
How did Louis Pasteur explain the cause and transmission of infectious disease?
meat broth in swan neck, one was opened (microbes entered) and the other closed (no microbes).
Pasteur proved that non-living objects can’t give rise to living organisms. disproving the theory of spontaneous generation and led to development of the germ theory
How did Robert Koch explain the cause and transmission of infectious disease?
Koch first proved that Bacillus anthracis is the cause of anthrax. He showed that the bacterium could be observed in the tissue of anthrax victims. He extracted the bacterium from a sheep which had died of anthrax, grew it and injected a mouse with it; and showed that the mouse developed the disease as well. Developed Koch’s postulates
Prove the germ theory (one disease is caused by one pathogen)
What is Koch’s Postulate?
Koch’s Postulate - A list of criteria which must be met to prove that a particular organism is the cause of a disease
What is the steps to Koch’s Postulate?
1) The same microorganism must be present in every diseased host, but absent from healthy hosts.
2) The microorganism must be isolated and cultured from a diseased host.
3) When a sample of the pure culture is inoculated into a healthy host, they must develop the same symptoms as the original host.
4) The microorganism must be able to be isolated from the second host, cultured and identified as the original species.
What are the reason for disease on agricultural production? there are 7
1) Increase mobility of the human population
2) Rise of intensive and industrial type agriculture (e.g feeding lots)
3) Changing patterns of land use (deforestation & loss of habitats)
4) Climate change
5) Antimicrobial resistant e.g) overuse of antimicrobials to treat infection mastitis (udder infection) in dairy cattle
6) Pesticide resistance
7) Loss of genetic Diversity (bad for the natural selection)
Effects of disease in Agriculture?
Death of affect animals → loss of appetite and weight loss
Low growth rate of young animals → loss of fertility through e.g) Leptospirosis (effects reproduction in cows)
Lack of economic value of individual animals e.g) warts in beef cattle
Economic loss to farmers → due to reduced meat, milk and wool yields
Loss of international trade
Human illness/disease
What is Panama Disease of Bananas? name pathogen, spread and symptoms and impact
fungus. spreads through root contact or contaminated soil or machinery. Crops destroyed and soil must be covered and quarantined
What is Foot Rot in Sheep? name pathogen, spread and symptoms and impact
Bacteria. spreads through Warm, wet weather and muddy ground. Limits the sheep’s ability to move and is contagious.
How does a pathogen establish an infection? (7 steps)
1) Enter the host - Respiratory, Gastrointestinal, Genitourinary tract or open wounds in skins,
2) Invasion - infiltrate cells or travel through the blood and tissue fluid
3) Establishes - themselves with adhesives
4) Multiply in host tissues - usually symptoms intensifies
5) Resist or not stimulate host defence mechanisms - biofilms, changing antigens, attack immune cells, or hiding
6) Damage the host
7) Go out and spreads to other organisms → direct and indirect contact
