1. AIDS25 Million since 1981
AIDS deaths in 2008 2.0 million
People living with HIV/AIDS in 2008 33.4 million
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome (AIDS or Aids) is a collection of symptoms and infections resulting from the specific damage to the immune system caused by the human immunodeficiency virus (HIV) in humans, and similar viruses in other species (SIV, FIV, etc.). The late stage of the condition leaves individuals susceptible to opportunistic infections and tumors. Although treatments for AIDS and HIV exist to decelerate the virus’ progression, there is currently no known cure. HIV, et al., are transmitted through direct contact of a mucous membrane or the bloodstream with a bodily fluid containing HIV, such as blood, semen, vaginal fluid, preseminal fluid, and breast milk. This transmission can come in the form of anal, vaginal or oral sex, blood transfusion, contaminated hypodermic needles, exchange between mother and baby during pregnancy, childbirth, or breastfeeding, or other exposure to one of the above bodily fluids. Most researchers believe that HIV originated in sub-Saharan Africa during the twentieth century; it is now a pandemic, with an estimated 38.6 million people now living with the disease worldwide.
How does AIDS effect the immune system?
Have you ever wondered what the immune system actually is? This explains the main features of the immune system and what AIDS does to destroy it.
AIDS gets a lot of press. Most of us know that it affects the immune system, and that the name is short for Acquired Immune Deficiency Syndrome. Most of us probably also know that the immune system helps protect us from infection. But how many of us know what the immune system actually is, or how it works?
The fact is, the immune system is no one thing. You can't pinpoint any specific part of the body and say "That's the immune system." It is so complex, that no body of science yet fully understands exactly how it all works. So let's go through the key points of what we do know, in order to gain a better understanding of this strange condition called AIDS.
The biggest organ of your immune system is your skin. Does that surprise you? Remember that the microbes that cause infection, whether they are bacteria, viruses or fungi, are all invisible to the human eye. So although we are surrounded by millions of them every day, we can't see them. Your skin helps prevent all those microbes from gaining access to your body. Think of it as fortress walls with electric fencing – that's the immune function of your skin. Your mucous membranes also form part of this fortress that keeps the microbes out.
Of course, no fortress is impenetrable. You may have a cut on your skin, or a wound. And of course, there are doorways into your body through your nose and mouth. Fortunately, these have little burglar alarms that alert the immune system when an intruder tries to make an uninvited entry.
The immune system, of course, has to be very smart. It has to know which cells belong to the body, and which don't. It does this by looking for little markers called antigens. Think of antigens as being little uniforms. All the cells in your body wear the same uniform, even though they may have different functions. Microbes coming into the body have their own uniforms, which are usually very different. Maybe they're even dressed in civvies, who knows.
Guard cells patrol the body all the time. There are small, quick-footed, lightly armed guards called microphages ("little eaters") which patrol the bloodstream. There are also bigger, slower, better-armed guards called macrophages ("big eaters") which hang around the spleen and lymph nodes, waiting to be called. They also patrol the body tissues.
Microphages are cells with powerful digestive enzymes and antibacterial substances. When a microphage sees a foreign uniform, it rushes over with a baton, bangs the microbe over the head and then gobbles it up to get rid of it. They are always first at the scene of the crime, and call for reinforcements from more powerful immune cells. It's quite possible that the microbes may be more powerful than the microphages, in which case it's the microphage that gets shot before it can wield the baton. The macrophages arrive afterwards, to collect the evidence and destroy any microbes that may have escaped the microphage guards.
Both microphages and macrophages come from the bone marrow. But the bone marrow also makes stem cells, which move to different parts of the body. These include other important immune organs like the thymus gland, spleen, lymph nodes, tonsils, appendix and Peyer's patches in the intestinal wall. Once settled into the organ, the stem cells produce white blood cells called lymphocytes.
Cells produce more cells by dividing into two cells. The daughter cells divide again, and so the process continues. The stem cells that go into the thymus gland divide very quickly, to produce a large number of daughter cells, most of which don't survive. Those that do, then leave the thymus gland and travel between the other immune organs at will. But they never return to the thymus.
These particular cells, formed in the thymus gland, are called T-lymphocytes or T-cells. And they learn special skills in the thymus gland which are very useful in fighting off foreign microbes.
When a T-cell reaches the scene of a crime, three things can happen. The foreign microbe can either inactivate or kill the T-cell. If it kills all the T-cells, the body can't see the foreign uniform any more and the microbe can go where it likes.
The T-cells can also start dividing. This means there are more cells that recognise the foreign uniform, which in turn means that if any more of these uniforms try and get into the body, the body can respond quicker and better.
The third thing the T-cell can do is release cytokines. This is a bit like casting a magic spell which makes the macrophages in the area stronger and more powerful, so that they can hit the microbes faster and have more chance of devouring them.
T-cells make up about 70% of the lymphocytes in the body. The rest are B-lymphocytes, which never go to the thymus gland. They don't travel as easily as T-cells, and they have different skills, including the ability to make antibodies which inactivate foreign particles.
HIV targets mainly the T-cells, specifically those which have a special receptor called a CD4 receptor. The virus attaches onto that receptor so that it can take over the inside of the cell. So we have a virus which looks – and acts like – a CD4 T-cell.
During the first stage of infection with HIV, the virus will kill a number of T-cells as it infects them. The immune system will react to the infection, and the body will display all the symptoms of an immune response such as fever, headache, tender lymph nodes, and generally feeling unwell.
However, once the B-cells have formed antibodies, the spread of infection stabilises. The symptoms disappear, and nothing seems to happen for a few months to several years.
But think what happens in the meantime. The virus has not been destroyed, just stabilised. There are antibodies, but not enough. The virus can continue to spread, although at a much slower rate.
Now think what happens when a microbe breaches the skin and enters the bloodstream. The immune systems sends the T-cells to fight the new microbe. But some of these T-cells are infected with HIV. They've lost their magic spells, and can either die from a microbe attack, or start dividing to make more T-cells. Except that they start making more virus-infected T-cells, which will eventually succumb to the virus. As more and more T-cells die, the body is less able to recognise foreign uniforms.
As time passes, the number of CD4 T-cells slowly drops, and the amount of virus slowly increases until a critical level is reached. Then the number of CD4 T-cells plummets, and the amount of virus in the bloodstream shoots up. Without the T-cells, the immune system becomes virtually useless. The foreign uniforms can march in unchallenged. Even an army of 98 lb. weaklings can come in and create havoc. These diseases – caused by everyday, normally harmless microbes – are the ones that usually define the beginning of AIDS.
Scientists have now developed tests to measure the amount of CD4 T-cells and the amount of virus in the body. When the T-cells get too low, or the virus gets too high, they can adjust the HIV treatment to restore a measure of law and order in the body. When pharmaceutical companies test their new anti-HIV drugs, they measure the T-cells and amount of virus in order to measure exactly how effective their drug is.
As a result of understanding the immune system better, people infected with HIV are able to live longer, healthier, productive lives. New research is leading scientists to consider the possibilities of cell transplants. Perhaps one day, our understanding will grow to the point that we know how to rebuild a defective immune system completely.
2. Colds, flu & Influenza
36,000 Deaths per year
63,730 annual deaths (NVSR September 2001)
Preventing colds, flu & influenza in the ill seasons. When is the flu season and how do they know what kind of flu I will get? What is the difference between cold and flu and how are they treated
The best medicine for colds and flus is preventive measures. Good hand washing and not sharing objects you touch with other infected persons. The pathogens in colds and flu’s are airborne, passed through coughing, sneezing, salvia, and touching things that have been touched by someone infected. There are several things on the market now a day to use, such as Lysol wipes, or antibacterial hand wash that requires no water you can use frequently. Receiving a yearly flu shot will also help decrease your chances of getting the flu.
Rule of thumb is the flu starts in Asia, and travels around the world. That is how they know what strain of flu will hit what area at what approximate time of the year. This has worked well for the past couple of decades. At times it is possible for the flu to mutate into another influenza, which has happened, but only to a moderate degree.
Although once you have had the flu, there is no mistaking the differences between a cold and flu, but some of the symptoms are the same just vary in degree.
3. Spanish FluBetween 1918-19: 50-100 Million dead
The Spanish flu (1918-1919) was exceptionally severe, and death rates were higher than with any other influenza pandemic to date. An estimated 500 million people were infected during this pandemic. This flu is not likely to re-emerge. Instead, experts believe a pandemic will likely be caused by an influenza subtype to which there is little, or no, preexisting immunity in humans.
What Is the Spanish Flu?
The 1918 flu, or "Spanish flu," caused the highest number of known influenza deaths. More than 500,000 people died in the United States, and up to 50 million people may have died worldwide. Many people died within the first few days after infection with the Spanish flu, and others died of related complications. Nearly half of those who died were young, healthy adults.
The Impact of Spanish Flu.
An estimated one third of the world's population (500 million people) were infected and had
flu symptoms during the Spanish flu. The Spanish flu was exceptionally severe, and death rates were higher than with any other influenza pandemic.
It is estimated that the total number of deaths from the Spanish flu ranged from 50 million to 100 million people.
What Caused It?
The specific virus that caused the Spanish flu was the influenza A (H1N1) virus, which appears to be an avian-like influenza virus derived from an unknown source.
Bubonic plague is mainly a disease in rodents and fleas (Xenopsylla cheopsis). Infection in a human occurs when a person is bitten by a flea that has been infected by biting a rodent that itself has been infected by the bite of a flea carrying the disease. The bacteria multiply inside the flea, sticking together to form a plug that blocks its stomach and causes it to begin to starve. The flea then voraciously bites a host and continues to feed, even though it can not quell its hunger, and consequently the flea vomits blood tainted with the bacteria back into the bite wound. The bubonic plague bacterium then infects a new victim, and the flea eventually dies from starvation. Any serious outbreak of plague is usually started by other disease outbreaks in rodents, or a rise in the rodent population.
5. Malaria2.7 Million Deaths per year-2800 children per day
1.272 million deaths per year world wide in 2002
Malaria is a Mosquito borne infectious disease. Malaria is popular in the region around the equator. That is, countries in Sub-Saharan Africa, Asia, and the Americas. It is transmitted majorly through the bite of the Anopheles Mosquito. the anopheles bites an infected person and then, and then a small amount of is taken by the Mosquito from the infected person and the parasite develops in the Mosquito. One week later when the Mosquito goes for feeding again, it bites someone else and infects the person through its saliva. After a period of time the parasite multiplies in the infected person's red blood cells. and then the person begins to notice symptoms like;fever, headache, and in worse situations(hallucinations, coma, and even death).
Some causes for the wide spread of malaria include;presence of stagnant water in which mosquito the carrier of malaria breeds, lack of hospitals and health care systems in the rural areas, and presence of counterfeit drugs. Also scientists recently discovered that the mosquitoes are getting resistant to malaria prevention drugs too.
According to figures released by the WHO, Malaria is responsible for one to three million deaths in a year. Especially in children under the age of five and also pregnant women. So this directly adds to the infant and maternal mortality rate worldwide. Thereby impending the actualization of the UN goals 4 and 5 respectively of the MDGs. Research also shows that if effective measures are not taken to combat malaria, the death rate could double in 20 years.
Since 1992 efforts have been made to combat this epidermic but it has had little or no result. but individuals can join the fight against malaria by making sure there are no stagnant water around them, by sleeping with insecticide treated nets, and by using insecticides. Governments could also help by providing hospitals and health care services in rural areas. though the malaria menace looks so far fetched but I believe that with co-operate effort, the malaria epidermic would be a thing of the past.
6. Ebola160,000 Deaths since 2000
The Ebola virus first emerged in 1976 in simultaneous outbreaks in Sudan and Zaire. It is known to be a zoonotic virus as it is currently devastating the populations of lowland gorillas in Central Africa. Despite considerable effort by the World Health Organization, no animal reservoir capable of sustaining the virus between outbreaks has been identified. However, it has been hypothesized that the most likely candidate is the fruit bat. Ebola hemorrhagic fever is potentially lethal and encompasses a range of symptoms including fever, vomiting, diarrhea, generalized pain or malaise, and sometimes internal and external bleeding. Mortality rates are generally very high, in the region of 80%, 90%, with the cause of death usually due to hypovolemic shock or organ failure.
7. Cholera12,000 Deaths since 1991
Cholera (or Asiatic cholera or epidemic cholera) is an extreme diarrheal disease caused by the bacterium Vibrio cholerae. Transmission to humans is by ingesting contaminated water or food. The major reservoir for cholera was long assumed to be humans, but some evidence suggests that it is the aquatic environment. In its most severe forms, cholera is one of the most rapidly fatal illnesses known—a healthy person may become hypotensive within an hour of the onset of symptoms and may die within 2-3 hours if no treatment is provided. More commonly, the disease progresses from the first liquid stool to shock in 4-12 hours, with death following in 18 hours to several days without re-hydration treatment.
8. SmallpoxNative Americans suffer a population drop from 12 Mil. to 235,000
Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. Smallpox is caused by either of two virus variants named Variola major and Variola minor. The deadlier form, V. major, has a mortality rate of 30–35%, while V. minor causes a milder form of disease called alastrim and kills ~1% of its victims. Long-term side-effects for survivors include the characteristic skin scars. Occasional side effects include blindness due to corneal ulcerations and infertility in male survivors. Smallpox killed an estimated 60 million Europeans, including five reigning European monarchs, in the 18th century alone. Up to 30% of those infected, including 80% of the children under 5 years of age, died from the disease, and one third of the survivors became blind. To this day, smallpox is the only human infectious disease to have been completely eradicated from nature.
9. Polio10,000 Deaths since 1916
and 1977 just 15
6. Ebola160,000 Deaths since 2000
The Ebola virus first emerged in 1976 in simultaneous outbreaks in Sudan and Zaire. It is known to be a zoonotic virus as it is currently devastating the populations of lowland gorillas in Central Africa. Despite considerable effort by the World Health Organization, no animal reservoir capable of sustaining the virus between outbreaks has been identified. However, it has been hypothesized that the most likely candidate is the fruit bat. Ebola hemorrhagic fever is potentially lethal and encompasses a range of symptoms including fever, vomiting, diarrhea, generalized pain or malaise, and sometimes internal and external bleeding. Mortality rates are generally very high, in the region of 80%, 90%, with the cause of death usually due to hypovolemic shock or organ failure.
7. Cholera12,000 Deaths since 1991
Cholera (or Asiatic cholera or epidemic cholera) is an extreme diarrheal disease caused by the bacterium Vibrio cholerae. Transmission to humans is by ingesting contaminated water or food. The major reservoir for cholera was long assumed to be humans, but some evidence suggests that it is the aquatic environment. In its most severe forms, cholera is one of the most rapidly fatal illnesses known—a healthy person may become hypotensive within an hour of the onset of symptoms and may die within 2-3 hours if no treatment is provided. More commonly, the disease progresses from the first liquid stool to shock in 4-12 hours, with death following in 18 hours to several days without re-hydration treatment.
What Causes Cholera?
Cholera is caused by bacteria called Vibrio cholerae, a gram-negative aerobic bacillus. It was discovered by Robert Koch in 1883 during an outbreak in Egypt. Cholera is derived from a Greek word that means "flow of bile." It is one of the most feared diarrheal diseases because of its severity.
Cholera, an acute diarrheal disease of the gastrointestinal tract, is caused by the bacterium Vibrio cholerae. The incubation period of cholera usually ranges from a few hours to five days after the bacteria is ingested. After ingesting the bacteria from infected drink or food, a small dose is enough to cause an infection.
After passing the acidic environment of the stomach, the bacteria then begin to multiply in the small intestine, where the environment is alkaline. It attaches itself to the microvilli of the epithelial cells lining the intestinal tract. It multiplies and produces an enterotoxin or cholera toxin. The enterotoxin causes increased release of water in the intestines, which produces severe diarrhea.
How Does a Person Get Cholera?
Cholera can be transmitted through fecal-oral route, which means one can get this illness from drinking water or eating food contaminated with Vibrio cholerae, the bacteria that causes cholera. Contamination usually originates from the feces or stool of an infected individual.
The bacterium may also thrive in brackish rivers and coastal waters. Shellfish that have been eaten raw or undercooked are also possible reservoirs for the cholera bacterium. However, the disease cannot be spread from direct contact with the infected person.
What are the Symptoms Associated with Cholera?
Most people do not exhibit symptoms. However, When symptoms occur, they start suddenly, around one to five days after acquiring the infection. The infected person may experience sudden, painless, watery diarrhea and vomiting. Fever is usually absent. The primary complaint of a person infected with cholera is profuse diarrhea and abdominal pain. These symptoms are caused by the release of toxins by V. cholera, causing large amounts of fluid to shift from the blood supply into the small and large intestines.
Diarrhea and vomiting range from mild to severe, and the infected person may lose more than one quart of water and salts in an hour. If not treated immediately, dehydration can become severe and the ill person may have intense thirst, muscle cramps, and weakness. The stool of a cholera patient looks gray and has flecks of mucus in it.
Other signs of dehydration include sunken eyes, little or no urine output, dry mouth, rapid pulse, unusual sleepiness or tiredness, and poor skin turgor. If dehydration is not treated immediately, it may lead to kidney failure, shock, and death. In most developing countries, the mortality rate among patients admitted without treatment is 60%. If treated promptly, the mortality rate is less than 1% and recovery is expected.
For those who survive, the symptoms usually subside in three to six days, and after two or more weeks most people will be free of the bacteria. Milder cases of cholera usually do not pose a threat to the patient and the person usually recovers on their own.
What are the Risk Factors Associated with Cholera?
People residing in places such as Latin America, Africa, or Asia are at risk for getting infected with cholera. Travelers going to these places are also at risk for exposure to the cholera bacterium. Eating raw and/or undercooked seafood can also pose a threat to people since the bacteria can thrive in brackish rivers and coastal waters.
There is also a risk for people who like eating food that was not prepared sanitarily. Densely populated, poor areas with little sanitation and unsatisfactory food hygiene are particularly affected by epidemics.
How to Prevent Cholera
To prevent cholera, make sure that your water supplies are clean, pure, and safe to consume. If not, boil the water first before drinking it. Bottled drinks, hot coffee and tea, and other sealed drinks are usually safe to drink. Avoid using doubtful ice cubes in drinks, unless you are sure that they are clean.
Avoid eating raw or undercooked fish and shellfish, and even fruits and vegetables, unless you peeled them yourself. Food must be properly prepared and you must avoid eating food that has stood at room temperature for several hours. Caution must also be observed when eating food from street vendors or stalls. Check to see if it is properly prepared, if possible.
If you plan to travel to places where cholera is endemic, you can get a cholera vaccine. However, it is only 50% effective and only lasts from three to six months.
Also keep in mind to that hand washing can deter the spread of bacteria and germs. Always wash your hands after using the toilet, before and after food preparation, and before eating your food.
Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. Smallpox is caused by either of two virus variants named Variola major and Variola minor. The deadlier form, V. major, has a mortality rate of 30–35%, while V. minor causes a milder form of disease called alastrim and kills ~1% of its victims. Long-term side-effects for survivors include the characteristic skin scars. Occasional side effects include blindness due to corneal ulcerations and infertility in male survivors. Smallpox killed an estimated 60 million Europeans, including five reigning European monarchs, in the 18th century alone. Up to 30% of those infected, including 80% of the children under 5 years of age, died from the disease, and one third of the survivors became blind. To this day, smallpox is the only human infectious disease to have been completely eradicated from nature.
9. Polio10,000 Deaths since 1916
and 1977 just 15
Poliomyelitis, often called polio or infantile paralysis, is an acute viral infectious disease spread from person to person, primarily via the fecal-oral route. The term derives from the Greek polio, meaning “grey”, melon, “spinal cord”, and -itis, which denotes inflammation. Although roughly 90% of polio infections are asymptomatic, affected individuals can exhibit a range of symptoms if the virus enters the blood stream. In less than 1% of polio cases the virus enters the central nervous system, preferentially infecting and destroying motor neurons, leading to muscle weakness and acute flaccid paralysis.
10. The Black Death75 million Deaths
The Black Death swept in on Europe from the East (probably Central Asia) and ravaged its population from 1347 to 1350. It first appeared on the shores of Italy from across the Mediterranean, carried, no doubt, by flea infested rats on merchant ships.
The Black Death, or The Black Plague, was one of the most deadly pandemics in human history. It probably began in Central Asia and spread to Europe by the late 1340s. The total number of deaths worldwide from the pandemic is estimated at 75 million people; there were an estimated 20 to 30 million deaths in Europe alone. The Black Death is estimated to have killed between one-third and two-thirds of Europe’s population.
