Research Assessment Flashcards
Describe the two forms of the Variola virus
Variola MAJOR - more dangerous form - has killed 30% of infected Variola MINOR - less deadly form - has killed 1% of infected
Is smallpox contagious?
Yes, highly contagious
How is smallpox transmitted?
Either through the inhalation of drops of infected saliva (through coughing, sneezing or speaking) or through coming into contact wth contaminated items.
What are the symptoms of smallpox?
Flu-like: - High fever - Fatigue - Muscular aches And a characteristic rash follows which develops into lesions which split, dry and then scab
Can death result from smallpox?
YES, if the virus attacks the circulatory system, bone marrow or respiratory system
What is smallpox caused by?
The variola virus, an orthopoxvirus
Which infectious disease has killed the most people?
Smallpox - it killed over 300 million in the 20th century
When and who developed the first smallpox vaccine?
1796, Edward Jenner
Why was the first smallpox vaccine not effective?
It was not widely used
Why was smallpox a big issue?
Due to:
- extreme poverty
- overcrowding
- poor hygiene and nutrition
How and when was smallpox eradicated?
- Eradicated in 1979
- The WHO introduced a worldwide mass immunisation program
What is polio caused by?
the poliovirus
What body parts does the poliovirus affect?
It multiples in the intestine from where it can attack the nervous system (and cause paralysis)
How is polio transmitted?
- From person-to-person via fecal-oral matter
- From a common vehicle (e.g. contaminated water and food)
What are the three types of polio infections?
Sub-clinical polio, non-paralytic polio and paralytic polio
What are the symptoms of sub-clinical polio?
- Headache
- Sore throat
- Fever
- Vomiting
What are the symptoms of non-paralytic polio?
- Same as sub-clinical
- Abnormal reflexes
- Problems swallowing
- Limb stiffness
- Muscle tenderness
What are the symptoms of paralytic polio?
- Same as non-paralytic
- Loss of reflexes
- Severe muscle spasms
- Sudden paralysis
- Deformed limbs
What can eventually develop from the poliovirus?
Full paralysis
Is there a cure for polio? If not, how can it be prevented
No, it can only be prevented by immunisation
Who invented the polio vaccine and was it successful?
Albert Sabin. Yes, it resulted with a 60-70% reduction in cases
When and how was polio eradicated? Was is successful?
In 1988, the World Health Assembly launched the Global Polio Eradication initiative which involved a widespread vaccination.
Yes, by 2000, there was a 99% reduction in cases
Where and why in the world is still affected by polio?
Afghanistan, Nigeria and Pakistan due to weak health systems and poor sanitation and hygiene.
How is the Stabin vaccine given?
It is an oral vaccine given at 2, 4 and 6 months and then a booster at school entry and at 15
What is diphtheria caused by?
The bacterium, Corynebacterium diphtheriae
What body parts does the diphtheria bacterium affect?
It is an infection of the throat and nose - The bacterium produces toxins that cause an abnormal membrane to grow in the throat, resulting in possible suffocation.
How is diphtheria transmitted?
- From person-to-person through contact with contaminated airborne saliva droplets
- From contact with items soiled with infected discharges
What are the symptoms of diphtheria?
- Runny nose
- Severe sore throat
- Fever
- Breathing/swallowing problems
- Skin sores that form ulcers
What was diphtheria known as and why?
“The deadly scourge of childhood” - 2/3 of cases were children under 5
When was the vaccine for diphtheria released?
1923
When were immunisation programs introduced in AUS and were they successful?
1930s and yes
What does the current immunisation program for diphtheria involve?
The triple antigen - diphtheria, whooping cough and tetanus.
Given at 2, 4 and 6 months and a booster at 15
Where and why in the world are areas still affected by diphtheria?
Quite a few but mainly India, Nepal, Indonesia, Vietnam and Iraq.
This is due to the poor living conditions - poor hygiene and nutrition
What is influenza caused by?
The influenza virus types A, B and C
What do types A and B of the influenza virus cause?
Seasonal epidemics of the disease in humans
What does type C of the influenza virus cause?
Milder respiratory issues
How is the influenza virus transmitted?
- Through the air in respiratory droplets expelled by infected individuals (through coughing, sneezing or talking)
- Through coming into contact with contaminated objects
What is the host’s response to the influenza virus?
- Infection of the virus triggers a series of immune responses to counteract the invading virus.
- The immune system has a mechanism involving MHC molecules which separate virally infected cells from healthy cells
- Cytotoxic T cells are then responsible for killing these virally infected cells
What are the major symptoms of the influenza virus?
- Fever
- Headache
- Fatigue
- Cough
- Sore throat
- Nasal congestion
- Body aches
- Diarrhea
How is influenza treated?
Antiviral medication can be taken but the recommended treatment is to stay in bed and rest, drink plenty of fluids and paracetamols/asprin can be taken to control fever and body aches
How can influenza be prevented?
Most effective way is to get the influenza vaccine and by incorporating infection control measures into your life:
- frequent hand washing with soap
- covering nose and mouth when sneezing and coughing
- avoid touching eyes, nose and mouth
- avoid contact with sick individuals
How is influenza controlled?
- Use of an inactivated vaccine - vaccinating individuals at high risk before seasonal increases in influenza virus circulation reduces influenza cases
- Antiviral medications
What is malaria caused by?
The Plasmodium parasite
How is malaria transmitted?
- Getting bitten by an infected mosquito
- Receiving contaminated blood during a blood transfusion
- From an infected mother to child during pregnancy
(There is a significant risk of getting malaria if one is travelling to an affected area)
How can malaria be prevented?
- Antimalarial medication
- Reducing exposure to mosquitoes:
- > using insect repellent on skin and sleeping area
- > mosquito bed nets sprayed with insecticide
- > wear protective clothing
Contribution of Alphonse Laveran to knowledge of malaria?
- Discovery of parasites in the blood of malaria patients
- Studied the lesions in the organs and blood of two different patients, realising that the constant element present was a black pigment - melanin
- Concluded that these granules were specific to malaria and originated in the blood
Contribution of Ronald Ross to knowledge of malaria?
- Showed that malaria parasites could be transmitted from infected patients to mosquitoes
- -> Dissected stomach tissue of mosquito that had fed on ill patient and found the malaria parasite
- Showed that mosquitoes can transmit malaria parasites from bird to bird
- -> Fed mosquitoes with infected birds and discovered that the parasite could move to the insect’s salivary glands where it can infect other birds during feeding
Contribution of Giovanni Grassi to knowledge of malaria?
- Complied a monograph on the identity and impact of different malarial parasites
- –> depicted that only the female Anopheles mosquito could transmit malaria
- Named the plasmodium vivax (a protozoan parasite and human pathogen)
What is quinine?
A naturally occurring anti-malarial drug made from the bark of the cinchona tree
Why was an alternative for quinine developed?
Due to excess bark stripping and the destruction of the quinine tree
Who created an artificial synthesis of quinine and when?
Robert Woodward and William Doering in 1944
What is used today as a vaccine against malaria?
Chloroquine and atabrine. However in areas where malaria parasites have developed a resistance to synthetic drugs (e.g. Vietnam), quinine is used
WHO efforts from the 1950s?
- 1955 launched a program to eradicate malaria worldwide with methods including:
- –> drug treatment and surveillance
- –> DDT residual spraying
- Set up hydroelectric reservoirs in the 1960s (E.g. in Puerto Rico)
What is meant by a drug resistance?
There is a growing concern that malaria parasites are developing widespread resistance to antimalarial drugs.
What is being done in response to the fear of a malaria drug resistance?
The WHO released the Global Plan for Artemisinin Resistance Containment in 2011 - aimed to prevent and contain artemisinin resistance
Is there a vaccine for malaria?
No, but there are vaccine projects in clinical trials.
RTS S/AS01 is the most advanced vaccine and has been undergoing trials since 2009
Lung cancer statistics in reference to the category of cancers?
- 5th most common cancer in AUS
- Most common cause of cancer death
What are the overall chances of each gender developing lung cancer in their lifetime?
- Men - 1/13
- Women - 1/16
Which age group is lung cancer most prevalent in?
2/3 of diagnosed patients are 65 or older
What % of lung cancer cases involves smoking for each gender?
- Men: 85%
- Women: 75%
How much greater a chance do smokers have of getting lung cancer than nonsmokers?
10%
What chance do nonsmokers have of developing lung cancer if they passive smoke?
20-30%
What are the causes and risk factors of lung cancer?
- Cigarette smoke and tobacco use
- –> directly inhaling the chemicals
- –> secondhand smoking
- Exposure to radon gas and air pollution
- Family history of lung cancer
- Previous lung diseases
What are the major symptoms of lung cancer?
- Coughing up blood
- Shortness of breath
- Chest pain
- Wheezing
- Chronic coughing
How is lung cancer treated?
Treatment depends on:
- –> stage of caner
- –> severity of the symptoms
- –> patient’s general health
- Non-small cell lung cancer (early-stage) is usually treated with surgery to remove the tumour and is sometimes followed up with radiotherapy and chemotherapy.
- Small cell lung cancer is usually treated with chemotherapy which involves the use of drugs to kill or slow down the growth of cancer cells
How is lung cancer managed in society?
By implementing methods to prevent this disease, it can be managed:
- Quitting smoking and avoiding areas where smoke is present
- Healthy diet
- Active lifestyle
- Avoiding carcinogens at work
What are prions?
Proteins that are capable of causing disease
Characteristics of prions?
They:
- do not have genetic material (i.e. DNA/RNA)
- non-cellular
- microscopic (smaller than other pathogens)
How do prions affect the body?
- They change normal proteins into infectious prion proteins
- These normal prion proteins are present mainly in he nerve cells of the brain and can therefore cause neuro issues (TSE - results in death)
Characteristics of viruses?
- Non-cellular
- Have both living and non-living characteristics
- Able to pass hereditary information
- Made up of a protective protein coat that encloses genetic material (DNA/RNA)
When do viruses reproduce?
When they are inside a host cell
What is bacteria?
Single celled prokaryotic organisms
Characteristics of bacteria?
- Have cell wall
- Genetic material is DNA
- No nucleus
- Present in different shapes
How does bacteria reproduce?
Asexually - binary fission
What types of bacteria are there?
Useful and harmful bacteria. Harmful bacteria produces toxic chemicals which cause diseases
What are protozoans?
Single-celled eukaryotic organisms
Characteristics of protozoans?
- Have cell membrane and nucleus
- Locomotive (can move from one place to another)
How do protozoans reproduce?
Asexually - binary fission
What are fungi?
Eukaryotic organisms
Characteristics of fungi?
- Can be unicellular or multicellular
- Have cell wall
- Don’t have chlorophyll
How do fungi reproduce?
Some reproduce asexually (e.g. yeast) and some an reproduce sexually
What diseases can fungi cause?
Athlete’s foot, thrush
What do fungal pathogens live on?
- Most fungal pathogens are dermatophytes - they live on skin, nails and hair
- Some live on dead plants (decomposers)
What are macroparasites?
Multicellular eukaryotic pathogens
What are the two groups of macroparasites?
Endoparasites and Ectoparasites
What are endoparasites?
- Live inside host’s body
- Includes flatworms and roundworms
- Causes liver fluke disease, tachiosis
What are ectoparasites?
- lives outside of the host’s body
- sucks blood
- injects toxins while feeding/sucking blood
- EG: fleas, ticks, leeches
