Est1 Task 2

TASK 2

Infectious diseases are the invasion of host organisms, (microbes) which can be invisible to the eyes. The microbes are also known as pathogens. A microbe infects an organism (which is known as the host of the microbe). In a human host, the microorganism causes a disease by either disrupting an important body process or by stimulating the immune system to mount a defensive reaction. The pathogen, interferes with the normal functioning of the host and can lead to chronic wounds, gangrene, loss of an infected limb, and even death. The host's response to infection is inflammation. An interaction between parasite and host, whereby the relationship is beneficial for the former but detrimental to the latter, is characterized as parasitism.

There are protozoal, anthropod , helminths, bacterial, and viral. Protozoa are one-celled organisms, they can multiply in the human body which allows them survival and permits serious infections to develop from just a single organism. An arthropod is an invertabrate having a skeleton, a segmented body and jointed appendages and they are larger than protozoa for example lice, ticks. Helminths are known as parasitic worms, are large multicellular organisms, which when mature can generally be seen with the naked eye. They are often referred to as intestinal worms even though not all helminths reside in the intestines. Bacteria are living things that have only one cell. Under a microscope, they look like balls, rods, or spirals. Many are helpful. Some bacteria help to digest food, destroy disease-causing cells, and give the body needed vitamins. Bacteria are also used in making healthy foods like yogurt. Viruses are capsules with genetic material inside. They are very tiny, much smaller than bacteria. Viruses cause familiar infectious diseases such as the common cold, flu and warts. They also cause severe illnesses such as HIV/AIDS,

Environmental illnesses can also be caused by the lifestyle of a person which depends on what a person eats or where the person lives. Chemicals in cigarettes can cause lung cancer so if a person is an active smoker, he or she may have lung cancer caused by the chemicals. Nutritional deficiencies occur when the body does not have the required amount of nutrients so this leads to different health problems like a defected bone growth, indigestion or even skin problems. Cardiovascular diseases are normally related to the heart or the blood vessels so these may be diseases like coronary heart diseases, strokes, peripheral arterial disease and more which may cause diabetes, obesity. Mainly, it is the person’s diet and lifestyle which may prevent such diseases. Disease caused by pollution might be caused by water pollution or air pollution, this is when the environment around a person is dirty. Examples are: Rickets, anemia,