Site author Richard Steane
The BioTopics website gives access to interactive resource material, developed to support the learning and teaching of Biology at a variety of levels.
|Disease||Caused by||(Signs) and Symptoms||Control/prevention||spread by|
(upper respiratory system infection)
|rhinovirus (many forms) and coronavirus (and others)
Image courtesy University of Melbourne
|scratchy throat, sore throat, nasal congestion, runny nose, sneezing, (cough, fever) - more pronounced in young children||Cold medicines should relieve symptoms (lowering temperature, etc) but there is no vaccine||airborne droplets (aerosols) from sneezes, coughs, etc or by contact
-contagious for the first 2 to 3 days, usually not after the first week.
(upper and occasionally lower respiratory system infection)
|chill, fever, sore throat, muscle pains, headache, cough, fatigue, general discomfort
More serious than the (common) cold
||airborne droplets (aerosols) from sneezes, coughs, etc or by contact with contaminated surfaces|
|Mumps||swelling of salivary glands, headache, fever, inflammation of testes (more important in teenagers and adults)||Mumps vaccine (part of MMR and MMRV* vaccines)||airborne droplets (aerosols) from sneezes, coughs, etc or by contact with surfaces
very easily spread in university/college scenarios
(also called rubeola, not to be confused with rubella)
|respiratory system infection, fever, cough, runny nose, red eyes, skin rash.||Measles vaccine (part of MMR and MMRV* vaccines)||airborne droplets (aerosols) from nose and mouth, etc or by contact
serious disease in some under-developed countries
|Rubella ("German measles")||minor flu-like symptoms and rash but if a woman is pregnant it can cause deafness, eye abnormalities, and congenital heart disease in baby||Rubella vaccine (part of MMR and MMRV* vaccines)||airborne droplet emission from the upper respiratory tract|
|Chickenpox||skin rash, muscle pain, nausea, fever, headache, sore throat, pain in both ears, complaints of pressure in head or swollen face, and malaise in adolescents and adults||varicella vaccine (part of MMRV* vaccines)||airborne - coughing or sneezing or through direct contact with secretions from the rash.|
|Shingles||varicella zoster virus reactivation after chickenpox infection - perhaps years before - virus travels down nerve to skin||painful, sensitive, tingling or burning skin eventually turning into a rash of red spots, fever, headache and enlarged lymph nodes.||
||Shingles rash can spread chickenpox if touched so no sharing towels, swimming, or contact sports.|
Acquired ImmunoDeficiency Syndrome
|progressive failure of the immune system allowing development of life-threatening opportunistic infections e.g. pneumonia and cancers||
||transfer of body fluids: blood, semen, vaginal fluid, pre-ejaculate, or breast milk
using non-sterile syringe needles (drug addicts or insecure health service)
|(HPV)||Small genital and other warts: may be insignificant (both sexes)
- may lead to cancer within the reproductive system, especially cervical cancer in females (major cause of cervical cancer)
||sexual activity, including oral sex|
|Blisters (cold sores) on lips, genitals (other parts of the body may be infected)||condoms
antivirals: acyclovir ACV (Zovirax)
|Skin-to-skin contact especially with active lesion or body fluid
Infection remains and can be reactivated (depending on health?)
|Caused by||(Signs) and Symptoms||Control/prevention||Spread|
Ebolavirus (EBOV) - named after the Ebola River in the Democratic Republic of the Congo (formerly known as Zaire), the location of the first known outbreak (in August 1976)
Image courtesy CDC
The virus particle has an unusual shape.
Other similar viruses - possibly resulting from mutations - are known for their effects on humans or other primates (some first seen in biological laboratories).
Ebola is a haemorrhagic fever, i.e. it causes high temperature and the escape of blood - internally or externally.
Some symptoms may initially resemble influenza, "stomach bugs" or malaria, but they then develop into a more serious phase.
Symptoms of Ebola include
It is thought that sufferers are infectious (i.e. can pass on the disease in body fluids) from the time symptoms appear, but these devlop gradually. The CDC says that Ebola is only contagious if the person is experiencing active symptoms.
In survivors, the virus may remain in parts of the body which are not subject to the protection of the immune system: the eyes, brain and spinal cord. It may be latent for some time, and in some cases cause meningitis (inflammation of the membranes surrounding the brain and spinal cord).
Similarly, it has been found that some male survivors produce virus particles in their semen for some time. Unprotected sex may therefore spread the virus.
Recovery from Ebola depends on good supportive clinical care and the patient’s immune response.
Oral reydration therapy (dilute solution of sugar and salts, taken by mouth) or intravenous therapy (similar solution, from a 'drip') are helpful.
In a community context Ebola cases need to be identified, isolated and treated. Possible contacts need to be traced, and treated in order to break the chains of transmission. Health care workers must strictly follow infection control (barrier nursing) in hospitals [or substitute buildings]. Safe burial practices may differ from traditional methods. It is better to check travellers before (or during?) flight than on arrival.
Specific chemical treatments for Ebola have not undergone some of the usual testing procedures. It may be said that the development of these drugs are subject to different economic and scientific influences in Africa and the western world.
Several chemicals seen as candidates for treating Ebola have been fast-tracked. Their potential side-effects and the lack of randomised clinical trials have been sidelined in the light of the perceived risks of Ebola.
Certain anti-viral drugs approved for other viral infections have been used in the treatment of Ebola, mostly in Africa, but it is difficult to compare their effectiveness as conditions are not standardised.
One possibility is the experimental drug ZMapp which is based on a combination of three monoclonal antibodies, aimed specifically at Ebola proteins.
There is at present no vaccine against Ebola, although some have been through 2 stages of testing in Africa, but this has stalled because large numbers of volunteers are needed for the next stage of testing. It has been suggested that blood serum from those who have survived an Ebola infection may be effective. People who recover from Ebola infection develop antibodies that last for at least 10 years.
Mainly by direct contact of the outer surface of the human body: skin (possibly damaged), eyes, nose, or mouth (mucous membranes) with blood or body fluids (urine, saliva, sweat, faeces, vomit, breast milk, or semen) from an infected individual.
Everyday social practices - handshakes etc - can cause widening of its spread in epidemic situations.
Transfer can also take place in a hospital setting via hypodermic needles and scalpel blades ("sharps") - sometimes re-used in certain circumstances.
Outbreaks are thought to have originated from wild (African) animals such as fruit bats and bushmeat - including monkey.
* It is not spread via the air by droplet infection. *
The virus is deactivated by normal disinfectants but it may be easily spread by sloppiness in hygiene.
Full (disposable) protective clothing including face masks is required for healthcare and associated personnel including those disposing of bodies, and this may be a special problem in hot conditions (especially when being removed).