Eojin2

Leukocytes are a type of white blood cells. White blood cells mean the general parts of the immune system. 5 types of white blood cells Eosinophils Lymphocytes Monocytes Basophils Neutrophils
 * 1. Describe the difference between leukocyte and white blood cells.**

Proteins are compounds consisted of short or long chains of amino acids (simplest form of proteins). For example, antibodies are considered as proteins. Membrane-bound antibodies on B cells are used to recognize, bond to, tag and disable pathogens. Membrane-bound antibodies are Y shaped antibodies consisted of 4 chains of amino acids; two sets of heavy and light chains.
 * 2. The term proteins are frequently used in the study of immunology. Explain the term/concept proteins.**

The Black Death, a bubonic plague, occurred during the Medieval Era (1347 - 1351), when hygiene levels were low, and the concepts of immunology was not recognized much. 500 years later the Black Death was then identified as a disease called Yersinia pestis, caused by fleas transmitted by rats transporting from and to countries by the trade routes. The three different types of the disease, bubonic, septicemic, and pneumonic all attacked different parts of the body, however caused similar symptoms, such as the black spots on skin. Because there were no vaccinations that can prevent the disease and antibiotics that can stop the plague, the disease was fatal. The disease was new at the time, therefore it was the first time the bodies of the victims have encountered the particular disease, or in other words, they were not immune to the disease. The Yersinia pestis viruses first enter the body by the rats / fleas or by direct contact with the infected. It will invade the body cells and inject toxins, thus making the cells unable to defend. The bacteria also infected the lymph nodes of the body, which is the cause for the black spots on skin. The pathogen can easily spread through the body by the bloodstreams and the body tissues, and will worsen the symptoms. The victims died in a few days after they have been infected, therefore it was very deadly. Nowadays, antibiotics will be able to kill these germs, unless antibiotic resistance comes into the picture and starts to reverse the effectiveness.
 * 3. Explain why the Black Death virus, which has caused millions of deaths, was deadly using concepts of immunology.**

__a) what does it mean - 20% fatality rate?__ Fatality rate means, in a specific area that has been infected, the ratio of the people who dies and the ones who live. So, 20% fatality rate will mean that 20% of a whole that has been infected will most likely die, or in other words, there is 80% chance of living when you have been infected.
 * 4. The recent bird flu virus, H7N9, has a 20% fatality rate if one is infected.**

__b) How is this virus different from a common flu virus?__ The H7N9 bird flu does not have person to person transmission, unlike other flue viruses. Usually normal flu can be spread from person to another by coughs, sneeze, etc., and it can spread in up to 6 feet in distance. however the H7N9 bird flu is not capable of transmitting the disease in that way.

__c) Are there ways to prepare our body immune system against such fatal, deadly virus?__ Vaccination is one good example to prevent or prepare our body’s immune system in case the disease enters the body. By vaccinating, you will be able to prevent the disease from invading your body. Vaccination is when vaccines are injected into the body. Vaccines are dead or disabled/weak pathogens for the flu. This tricks the body's immune system to think that the real pathogen has entered the body. Although vaccines will never harm the body literally, its role is to make the immune system have a "practice" of killing or defending the germs from invading the body. The immune system will produce antibodies to defend the vaccines, and so plasma and memory cells will be produced. The plasma cells are the actual cells that produce the antibodies and defend when the real pathogen enters the body, however the memory cells have a big role in remembering the pathogen in case the pathogen enters the body again. Although vaccination does not create 100% prevention, the average vaccine efficiency is around 60-70%.

__d) The bird flu virus wasn't infectious to humans before; explain why it suddenly turned viral and harmful to humans.__ It may have been the antibiotic resistance, or it could be the overuse of drugs to chickens/ poultry that suddenly rouse the infection to surface.

__e) Right now, the flu is unable to infect a person through human to human transmission; if it can infect through human to human transmissions, what could have changed in the virus?__ The fatality rate may be higher, and more people would have been infected, since person to person contact is higher than flu and person contact. The virus will be more deadly and vaccinations would be needed desperately.