Project why do we fall ill

One way is to use medicines that kill microbes. We have seen earlier that microbes can be classified into different categories. They are viruses, bacteria, fungi or protozoa. Each of these groups of organisms will have some essential biochemical life process which is peculiar to that group and not shared with the other groups. These processes may be pathways for the synthesis of new substances or respiration. These pathways will not be used by us either.

For example, our cells may make new substances by a mechanism different from that used by bacteria. We have to find a drug that blocks the bacterial synthesis pathway without affecting our own. This is what is achieved by the antibiotics that we are all familiar with.

Similarly, there are drugs that kill protozoa such as the malarial parasite. One reason why making anti-viral medicines is harder than making antibacterial medicines is that viruses have few biochemical mechanisms of their own.

They enter our cells and use our machinery for their life processes. This means that there are relatively few virus-specific targets to aim at. Despite this limitation, there are now effective anti-viral drugs,for example, the drugs that keep HIV infection under control. All of what we have talked about so far deals with how to get rid of an infection in someone who has the disease.

But there are three limitations of this approach to dealing with infectious disease. The first is that once someone has a disease, their body functions are damaged and may never recover completely. The second is that treatment will take time, which means that someone suffering from a disease is likely to be bedridden for some time even if we can give proper treatment.

The third is that the person suffering from an infectious disease can serve as the source from where the infection may spread to other people. This leads to the multiplication of the above difficulties. It is because of such reasons that prevention of diseases is better than their cure.

How can we prevent diseases? There are two ways, one general and one specific to each disease. The general ways of preventing infections mostly relate to preventing exposure. How can we prevent exposure to infectious microbes? If we look at the means of their spreading, we can get some easy answers. For airborne microbes, we can prevent exposure by providing living conditions that are not overcrowded. For water-borne microbes, we can prevent exposure by providing safe drinking water.

This can be done by treating the water to kill any microbial contamination. For vector-borne infections, we can provide clean environments. This would not, for example, allow mosquito breeding. In other words, public hygiene is one basic key to the prevention of infectious diseases.

In addition to these issues that relate to the environment, there are some other general principles to prevent infectious diseases. To appreciate those principles, let us ask a question we have not looked at so far. Normally, we are faced with infections everyday. If someone is suffering from a cold and cough in the class, it is likely that the children sitting around will be exposed to the infection. But all of them do not actually suffer from the disease.

Why not? This is because the immune system of our body is normally fighting off microbes. We have cells that specialise in killing infecting microbes. These cells go into action each time infecting microbes enter the body. If they are successful, we do not actually come down with any disease.

The immune cells manage to kill off the infection long before it assumes major proportions. As we noted earlier, if the number of the infecting microbes is controlled, the manifestations of disease will be minor.

In other words, becoming exposed to or infected with an infectious microbe does not necessarily mean developing noticeable disease.

So, one way of looking at severe infectious diseases is that it represents a lack of success of the immune system. The functioning of the immune system, like any other system in our body, will not be good if proper and sufficient nourishment and food is not available. Therefore,the second basic principle of prevention of infectious disease is the availability of proper and sufficient food for everyone.

These are the general ways of preventing infections. What are the specific ways? They relate to a peculiar property of the immune system that usually fights off microbial infections. Let us cite an example to try and understand this property. These days, there is no smallpox anywhere in the world. But as recently as a hundred years ago, smallpox epidemics were not at all uncommon. In such an epidemic, people used to be very afraid of coming near someone suffering from the disease since they were afraid of catching the disease.

However, there was one group of people who did not have this fear. These people would provide nursing care for the victims of smallpox. This was a group of people who had had smallpox earlier and survived it, although with a lot of scarring. In other words, if you had smallpox once, there was no chance of suffering from it again.

So, having the disease once was a means of preventing subsequent attacks of the same disease. This happens because when the immune system first sees an infectious microbe, it responds against it and then remembers it specifically. So the next time that particular microbe, or its close relatives enter the body, the immune system responds with even greater vigour.

This eliminates the infection even more quickly than the first time around. This is the basis of the principle of immunisation. Traditional Indian and Chinese medicinal systems sometimes deliberately rubbed the skin crusts from smallpox victims into the skin of healthy people. They thus hoped to induce a mild form of smallpox that would create resistance against the disease. Famously, two centuries ago, an English physician named Edward Jenner, realised that milkmaids who had had cowpox did not catch smallpox even during e p i d e m i c s.

Cowpox is a very mild disease. Jenner tried deliberately giving cowpox to people as he can be seen doing in the picture , and found that they were now resistant to smallpox. This was because the smallpox virus is closely related to the cowpox virus.

This does not actually cause the disease but this would prevent any subsequent exposure to the infecting microbe from turning into actual disease. Many such vaccines are now available for preventing a whole range of infectious diseases, and provide a disease-specific means of prevention.

There are vaccines against tetanus, diphtheria, whooping cough, measles, polio and many others. These formthe public health programme of childhood immunisation for preventing infectious diseases. Of course, such a programme can be useful only if such health measures are available to all children.

Can you think of reasons why this should be so? Some hepatitis viruses, which cause jaundice, are transmitted through water. There is a vaccine for one of them, hepatitis A, in the market. But the majority of children in many parts of India are already immune to hepatitis A by the time they are five years old. This is because they are exposed to the virus through water. Under these circumstances, would you take the vaccine? Toggle navigation. Why making anti-viral medicines is harder than making anti-bacterial medicines?

Are you worried or stressed? Click here for Expert Advice. Gurmeet Kaur. Comment 2. Post Comment. Disclaimer: Comments will be moderated by Jagranjosh editorial team. Comments that are abusive, personal, incendiary or irrelevant will not be published. Please use a genuine email ID and provide your name, to avoid rejection. Comments god Jun 16, For example, Cancer, HIV, and more related ones. If microbes happen to be the immediate cause of a disease, then they are listed under infectious causes.

These are not caused by any infectious agents or external factors. Besides, usually, these are caused by internal factors. Image to be added soon. Below are a few tips for disease-free and healthy living. This helps to diagnose the disease at its early stage, and the treatment becomes easier.

Thereby, we can make sure to go for health screening tests. Doing physical exercises daily keeps us active. It also energizes our body and keeps us healthy. A balanced diet is an essential aspect in the prevention of diseases. Consuming healthy and nutritional food keeps us fit and prevents any diseases. Obesity is one of the greater causes of heart problems and increased cholesterol.

Fungal disease targets 6. Why do only female mosquitoes act as vectors? Name two diseases transmitted by contaminated food and water. Name the disease transmitted by dog bite. Name two barriers , which prevent the entry of microbes in the body. What is the major drawback of principle of treatment? Name the diseases , which are transmitted from the expectant mother to the foetus. Who are reservoir hosts? Why are they called so? Making antiviral medicines is harder than making anti bacterial medicines.

Give reason. List organ specific symptoms of : a Lung cancer b Hepatitis