The body reacts to disease-causing bacteria by increasing local blood flow inflammation and sending in cells from the immune system to attack and destroy the bacteria.
Antibodies produced by the immune system attach to the bacteria and help in their destruction. They may also inactivate toxins produced by particular pathogens, for example tetanus and diphtheria.
Immunisation is available to prevent many important bacterial diseases such as Hemophilus influenza Type b Hib , tetanus and whooping cough.. A virus is a miniscule pocket of protein that contains genetic material. If you placed a virus next to a bacterium, the virus would be dwarfed. For example, the polio virus is around 50 times smaller than a Streptococci bacterium, which itself is only 0.
The four main types of virus include:. This makes it difficult for antibodies to reach them. Some special immune system cells, called T-lymphocytes, can recognise and kill cells containing viruses, since the surface of infected cells is changed when the virus begins to multiply.
Many viruses, when released from infected cells, will be effectively knocked out by antibodies that have been produced in response to infection or previous immunisation. Antibiotics are useless against viral infections. This is because viruses are so simple that they use their host cells to perform their activities for them. So antiviral drugs work differently to antibiotics, by interfering with the viral enzymes instead. Antiviral drugs are currently only effective against a few viral diseases, such as influenza, herpes, hepatitis B and C and HIV — but research is ongoing.
A naturally occurring protein, called interferon which the body produces to help fight viral infections , can now be produced in the laboratory and is used to treat hepatitis C infections. It is possible to vaccinate against many serious viral infections such as measles, mumps, hepatitis A and hepatitis B.
An aggressive worldwide vaccination campaign, headed by the World Health Organization WHO , managed to wipe out smallpox. However, some viruses — such as those that cause the common cold — are capable of mutating from one person to the next. This is how an infection with essentially the same virus can keep dodging the immune system. Vaccination for these kinds of viruses is difficult, because the viruses have already changed their format by the time vaccines are developed.
This page has been produced in consultation with and approved by:. A lot of what we touch likely ends up on our phones. As with other surfaces, the greatest risk is in healthcare settings. When was the last time you cleaned your phone?
A 70 per cent isopropyl alcohol solution or other cleaning method suggested by the manufacturer of your device, done regularly, would improve things a lot. As the restrictions lift and we return to the outside world, be mindful of what you touch.
The best step you can take to avoid getting sick is to wash your hands. How germs spread from surfaces Many of us have become obsessed with the world of microorganisms during the COVID pandemic. Microorganisms are all around and on us, but we rarely see them unless we grow them in large enough numbers. Cardboard, wood and cloth: safety in pores The kind of surface matters. Microorganisms like viruses might disappear into a porous surface. Not to scale.
Image by the Australian Academy of Science. Although non-porous surfaces are easier to disinfect, porous surfaces might result in less transmission. In a study, food that was dropped on carpet was much less likely to be contaminated than food that fell on tile or stainless steel.
All a pathogen needs to thrive and survive is a host. Pathogens can be transmitted a few ways depending on the type. They can be spread through skin contact, bodily fluids, airborne particles, contact with feces, and touching a surface touched by an infected person. They then use the components of the host cell to replicate, producing more viruses.
After the replication cycle is complete, these new viruses are released from the host cell. This usually damages or destroys the infected cells. Some viruses can remain dormant for a time before multiplying again. When this happens, a person appears to have recovered from the viral infection , but gets sick again. Antibiotics do not kill viruses and therefore are ineffective as a treatment for viral infections.
Antiviral medications can sometimes be used, depending on the virus. Bacteria are microorganisms made of a single cell. They are very diverse, have a variety of shapes and features, and have the ability to live in just about any environment, including in and on your body.
Not all bacteria cause infections. Those that can are called pathogenic bacteria. Your body can be more prone to bacterial infections when your immune system is compromised by a virus. The disease state caused by a virus enables normally harmless bacteria to become pathogenic. Antibiotics are used to treat bacterial infections.
You can see that most of the problems are due to improper or unhygienic handling of foods. No matter whether the bacteria can form spore or not, storage of potentially hazardous food outside the danger zone 4 to 60 o C can prevent the growth of the pathogenic bacteria.
You can find from the table in the previous page that most pathogenic bacteria can grow at danger zone temperature. Although Listeria monocytogenes can survive and multiply at 0 o C, it can be destroyed by normal cooking. It is important to avoid post-cooking contamination of ready-to-eat food and prolonged storage of raw foods that may contain this bacterium.
In general, cooking food to an internal temperature of 75 o C for at least 30 seconds can kill most of the pathogenic bacteria but not the spore form. Different characteristics of pathogenic bacteria may aid in causing foodborne disease, but the primary causes of food poisoning are improper or unhygienic handling of foods by humans. More emphasis on the proper food handling practices can readily reduce risk of bacterial food poisoning.
0コメント