Infectious diseases:

Some of you may have heard about the great bubonic plague, a fatal disease of the blood, spread by fleas and respiratory  secretions. It occurred in epidemic proportions throughout most of Europe from thirteenth  to nineteenth century. A major outbreak of plague in India occurred in  1896 and lasted for fifteen years. It swept through villages and towns and killed over eight million people.  It seems that such diseases were common in ancient times. Increased trade and commerce and resultant human traffic made them reach new places all over the world. Similarly, diseases such as small pox, measles, influenza and cholera spread easily from one person  to  another, and from one area to another.

The reason for the spread of these diseases, and many others, was not known till the nineteenth  century. Till then, such diseases always left people struck with terror because their causes were shrouded in mystery. Due to ignorance, demons and evil spirits were blamed  for causing these diseases. In India, it was believed that these diseases weie a punishment from angry deities. A new Goddess was created and held responsible for each disease. For example "Stela Ma"  is said to cause small pox. People worshipped her to get cured from this disease.  It would be interesting to note here that small pox has been eradicated from this planet due to a planned world-wide vaccination campaign. Plague outbreaks do not occur any more. 

The poem given in the margin which children often sing while playing, is  jointly  sung at a memorial service outside the village Eyam in England to pay homage to the townsfolk who gave their lives three centuries ago to save others from  the disease. These people got affected by plague.  In order to stop the spread of disease they confined themselves in their village to save others. The ring of rosies refers to tbe rose-shaped  splotches on a plague victim. Posies were little flowers used to ward off the evil spirit. And Achoo! means sneezing which accompanied the disease. The last line means that they all died. You must have experienced that if somebody in the family is suffering from a cough or cold you often catch it. Do you know why?

Because these diseases are caused by germs or "microbes"  which can go from one person to another. "Microbes"  means minute organisms or germs. They are so small that we cannot see them with the naked eye. Some can be seen with the help of an ordinary microscope while others are smaller still and can be seen only under very special microscopes. Certain infectious diseases are caused by worms. We will also discuss how they spread from one perso-  another.