Human Health Introduction

The harmful microbes are present everywhere. They can survive even in inhospitable conditions. These are in the soil, in the air we breathe, in the food we eat and in the water we use for drinking or bathing. Microbes enter our body through the natural openings of the body such as mouth, nose, eyes, urinary and reproductive passages. These, on entering our body, get multiplied very fast. In a few days a single bacterium can produce millions of it and these in turn infect millions of cells at the site of infection. But virus is reproduced only in the living cells or live tissues of man and animal beings.

Many microbes are even useful to human race and are very important even for existence of life on the earth. Without these micro organisms life on earth would even perish. For example, we are making use of useful bacteria in the preparation of curds, alcohol, bread and cakes. These micro organisms decompose dead plants and animals and sewage into harmless chemicals such as CO2, water etc.

Useful Microbes

i. lactobacillus bacteria are responsible for the curd formation. Yeast which is used commercially for alcohol and wine production. The production is called fermentation. Yeast is also used in baking industries for the preparations of bread and cake.

ii. Nitrogen-fixing bacteria take nitrogen gas from the air (which animals and plants need but cannot use directly in that form) and turn it into nitrogen compounds that plants use as nutrients to build their bodies. Azotobacter and Clostridium are examples of nitrogen fixing bacteria

iii. Saprophytic bacteria help clear the earth of dead organisms by decomposing them. This process also recycles nutrients back into the soil for plants to use to build their bodies at the beginning of the food chain.

iv. Bioremediation is a process that uses of biological organisms to treat and break down hazardous wastes and pollutants into harmless materials. Pseudomonas putida is a soil bacterium that involved in the bioremediation of toluene

Harmful Microbes

i. Some bacteria cause food to spoil and/or may produce toxins that can cause food poison. Two types of food poisoning are Salmonella (common) and Clostridium botulism (a rare but deadly form).

ii. Escherichia coli causes of food borne illness. Infection often leads to bloody diarrhea.

iii. Mycobacterium causes of tuberculosis. First discovered in 1882 by Robert Koch