Global deadly diseases

Problem

According to World Health Organization figures, the following are the most deadly diseases in the world. The first figure is the annual mortality rate and the following is the percentage of all deaths. For example, of 57 million total deaths worldwide, heart disease accounts for more than 12.8%

Ischaemic heart disease 7.25 million 12.8%
Any of several abnormalities of the heart and its function in maintaining blood circulation. Heart disease is the cause of approximately half the deaths in the United States each year. Among the most common causes of heart disease are degenerative changes in the coronary blood vessels, infectious diseases, and congenital heart disease. Congenital defects result from abnormal development of the fetal heart, commonly in the valves or septa. Such defects can be precipitated by environmental conditions in the uterus, such as the presence of the rubella virus, or they can be inherited. Infectious diseases acquired after birth, such as rheumatic fever, syphilis, and endocarditis, can also damage the valves of the heart. In addition, the heart muscle itself can be affected: hypertensive heart disease (see hypertension) can cause it to enlarge, and it can become inflamed by rheumatic fever. Arteriosclerotic depositions in the coronary arteries result in the narrowing of these vessels, causing insufficient blood flow and oxygen to the heart muscle, a condition known as coronary artery disease. The characteristic radiating chest pain, angina pectoris, is the most prominent symptom of this condition. Coronary arteries already narrowed by arteriosclerosis are made susceptible to blockage by a clot (coronary thrombosis), causing the death of the heart muscle supplied by the affected artery, a life-threatening event called a myocardial infarction, or heart attack. Hypertensive, coronary, congenital, and other forms of cardiovascular disease, either singly or in combination, can lead to a state in which the heart is unable to expel sufficient blood for the metabolic demands of the body, ultimately resulting in congestive heart failure. Disturbances in the normal heartbeat, called arrhythmias, can occur by themselves or in conjunction with other heart problems, for example infarction affecting the area of the heart that controls the heartbeat.

Cerebrovascular disease 6.15 million 10.8
Refers to a group of conditions that affect the circulation of blood to the brain, causing limited or no blood flow to affected areas of the brain. Atherosclerosis is one of the conditions that can cause cerebrovascular disease. During this process, high cholesterol levels coupled with inflammation in areas of the arteries in the brain can cause the cholesterol to build up in the vessel in the form of a thick, waxy plaque. This plaque can limit, or completely obstruct, blood flow to the brain, causing a stroke, transient ischemic attacks, or dementia, which may lead to a variety of other health complications. The most common forms of cerebrovascular disease are cerebral thrombosis (40% of cases) and cerebral embolism (30%), followed by cerebral hemorrhage (20%).

Lower respiratory infections 3.46 million 6.1
Respiratory tract system is one of the most important mechanisms of the human body, which helps in breathing. This system consists of a trachea or wind pipe and a pair of lungs. Like all the other systems in the body, respiratory system is also affected by certain infections, since it is exposed to external factors, in comparison to the rest of the body systems. The respiratory tract infection can be classified under two categories namely; lower and upper respiratory infection. Lower respiratory infection (LRI) which is also referred to as lower respiratory tract infection, is a type of infection that affects the lower respiratory tract and is more serious than upper respiratory tract infections.
Read more at Buzzle: http://www.buzzle.com/articles/lower-respiratory-infection.html

Chronic obstructive pulmonary disease 3.28 million 5.8
COPD is almost always caused by smoking. Over time, breathing tobacco smoke irritates the airways and destroys the stretchy fibers in the lungs. Other things that may put you at risk include breathing chemical fumes, dust, or air pollution over a long period of time. Secondhand smoke also may damage the lungs. It usually takes many years for the lung damage to start causing symptoms, so COPD is most common in people who are older than 60. You may be more likely to get COPD if you had a lot of serious lung infections when you were a child. People who get emphysema in their 30s or 40s may have a disorder that runs in families, called alpha-1 antitrypsin deficiency. But this is rare.

Diarrhoeal diseases 2.46 million 4.3
Frequent discharge of watery feces from the intestines, sometimes containing blood and mucus. It can be caused by excessive indulgence in alcohol or other liquids or foods that prove irritating to the stomach or intestine, by allergy to certain food products, by poisoning with heavy metals, by chemicals such as are found in cathartics, by hyperactivity of the nervous system, and by infection with a virus (intestinal grippe) or with bacteria or their toxins. Diarrhea is a concomitant of many infectious diseases, especially typhoid fever, bacillary or amebic dysentery, and cholera. Persistent diarrhea may result in severe dehydration and shock. It is therefore necessary to replace the fluid lost by the body. Treatment is with a bland diet and drugs that will decrease the activity of the intestines, as well as with specific measures directed at the underlying cause. The elderly are at especially high risk for diarrheal deaths caused by viruses. Ulcerative colitis is an inflamatory and ulcerative disease of the colon, properly described as "irritable bowl," and characterized by bloody diarrhea. Crohn's disease affects the distal ileum and colon, but may occur in any part of the gastrointestinal tract, from the mouth to the anus and perianal area. The symptoms are chronic diarrhea associated with abdominal pain, fever, anorexia, weight loss, and a mass or fullness in the right lower quadrant (of the abdomen).

HIV/AIDS 1.78 million 3.1
A positive diagnosis of HIV infection can be made with several types of tests, including virus culture, antibody testing, and polymerase chain reaction (PCR). Generally, HIV infection is diagnosed by showing that specific antibodies fighting the infection are present in the blood. Antibodies against HIV are usually detectable approximately 25 days after infection, and nearly all infected individuals are HIV antibody-positive after 12 weeks.
Antigen Alert One of the major reasons antiretroviral treatment of HIV infections has not been more successful is the development of drug-resistant HIV strains in patients during therapy. Identifying such strains early can help improve the effectiveness of treatment. False-negative tests can arise because it may take several weeks after initial infection for the body to produce antibodies. Rapid tests can generate results in less than 30 minutes, analyzing blood, saliva, or urine.

Trachea, bronchus, lung cancers 1.39 million 2.4
Cancer is really a group of diseases. There are more than 100 different types of cancer, but they all are a disease of some of the body's cells. Healthy cells that make up the body's tissues grow, divide, and replace themselves in an orderly way. This process keeps the body in good repair. Sometimes, however, normal cells lose their ability to limit and direct their growth. They divide too rapidly and grow without any order. Too much tissue is produced and tumors begin to form. Tumors can be either benign or malignant. Benign tumors are not cancer. They do not spread to other parts of the body and they are seldom a threat to life. Often, benign tumors can be removed by surgery, and they are not likely to return. Malignant tumors are cancer. They can invade and destroy nearby tissue and organs. Cancer cells also can spread, or metastasize, to other parts of the body, and form new tumors. Because cancer can spread, it is important for the doctor to find out as early as possible if a tumor is present and if it is cancer. As soon as a diagnosis is made, treatment can begin.

Tuberculosis 1.34 million 2.4
TB-causing bacteria is passed from person to person through the air when someone with the disease coughs or sneezes. People who are nearby may get infected after breathing in bacteria. The bacteria can attack any part of the body, but they usually stick to the lungs. People with TB disease are most likely to spread it to those they spend time with every day, like their family or co-workers.

Diabetes mellitus 1.26 million 2.2
A chronic disorder of glucose (sugar) metabolism caused by inadequate production or use of insulin, a hormone produced in specialized cells (beta cells in the islets of Langerhans) in the pancreas that allows the body to use and store glucose. It is a leading cause of death in the United States and is especially prevalent among African Americans. The treatment of diabetes was revolutionized when F. G. Banting and C. H. Best isolated insulin in 1921.

Hypertensive heart disease 1.15 million 2.0
Any of several abnormalities of the heart and its function in maintaining blood circulation. Heart disease is the cause of approximately half the deaths in the United States each year. Among the most common causes of heart disease are degenerative changes in the coronary blood vessels, infectious diseases, and congenital heart disease. Congenital defects result from abnormal development of the fetal heart, commonly in the valves or septa. Such defects can be precipitated by environmental conditions in the uterus, such as the presence of the rubella virus, or they can be inherited. Infectious diseases acquired after birth, such as rheumatic fever, syphilis, and endocarditis, can also damage the valves of the heart. In addition, the heart muscle itself can be affected: hypertensive heart disease (see hypertension) can cause it to enlarge, and it can become inflamed by rheumatic fever. Arteriosclerotic depositions in the coronary arteries result in the narrowing of these vessels, causing insufficient blood flow and oxygen to the heart muscle, a condition known as coronary artery disease. The characteristic radiating chest pain, angina pectoris, is the most prominent symptom of this condition. Coronary arteries already narrowed by arteriosclerosis are made susceptible to blockage by a clot (coronary thrombosis), causing the death of the heart muscle supplied by the affected artery, a life-threatening event called a myocardial infarction, or heart attack. Hypertensive, coronary, congenital, and other forms of cardiovascular disease, either singly or in combination, can lead to a state in which the heart is unable to expel sufficient blood for the metabolic demands of the body, ultimately resulting in congestive heart failure. Disturbances in the normal heartbeat, called arrhythmias, can occur by themselves or in conjunction with other heart problems, for example infarction affecting the area of the heart that controls the heartbeat.

http://www.who.int/en/