BLOOD CANCER ( LEUKEMIA )

Leukemia :




Leukemia (British English: leukaemia) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). Leukemia is a broad term covering a spectrum of diseases. In turn, it is part of the even broader group of diseases called hematological neoplasms.


CLASSIFICATIONS :


Leukemia is clinically and pathologically subdivided into several large groups. The first division is between its acute and chronic forms:

Acute leukemia is characterized by the rapid increase of immature blood cells. This crowding makes the bone marrow unable to produce healthy blood cells. Immediate treatment is required in acute leukemia due to the rapid progression and accumulation of the malignant cells, which then spill over into the bloodstream and spread to other organs of the body. Acute forms of leukemia are the most common forms of leukemia in children.




Chronic leukemia is distinguished by the excessive build up of relatively mature, but still abnormal, white blood cells. Typically taking months or years to progress, the cells are produced at a much higher rate than normal cells, resulting in many abnormal white blood cells in the blood. Whereas acute leukemia must be treated immediately, chronic forms are sometimes monitored for some time before treatment to ensure maximum effectiveness of therapy. Chronic leukemia mostly occurs in older people, but can theoretically occur in any age gro



Symptoms:


Damage to the bone marrow, by way of displacing the normal bone marrow cells with higher numbers of immature white blood cells, results in a lack of blood platelets, which are important in the blood clotting process. This means people with leukemia may easily become bruised, bleed excessively, or develop pinprick bleeds (petechiae).
White blood cells, which are involved in fighting pathogens, may be suppressed or dysfunctional. This could cause the patient's immune system to be unable to fight off a simple infection or to start attacking other body cells. Because leukemia prevents the immune system from working normally, some patients experience frequent infection, ranging from infected tonsils, sores in the mouth, or diarrhea to life-threatening pneumonia or opportunistic infections.
Finally, the red blood cell deficiency leads to anemia, which may cause dyspnea and pallor.
Some patients experience other symptoms. These symptoms might include feeling sick, such as having fevers, chills, night sweats and other flu-like symptoms, or feeling fatigued. Some patients experience nausea or a feeling of fullness due to an enlarged liver and spleen; this can result in unintentional weight loss. If the leukemic cells invade the central nervous system, then neurological symptoms (notably headaches) can occur.
All symptoms associated with leukemia can be attributed to other diseases. Consequently, leukemia is always diagnosed through medical tests.
The word leukemia, which means 'white blood', is derived from the disease's namesake high white blood cell counts that most leukemia patients have before treatment. The high number of white blood cells are apparent when a blood sample is viewed under a microscope. Frequently, these extra white blood cells are immature or dysfunctional. The excessive number of cells can also interfere with the level of other cells, causing a harmful imbalance in the blood count.
Some leukemia patients do not have high white blood cell counts visible during a regular blood count. This less-common condition is called aleukemia. The bone marrow still contains cancerous white blood cells which disrupt the normal production of blood cells. However, the leukemic cells are staying in the marrow instead of entering the bloodstream, where they would be visible in a blood test. For an aleukemic patient, the white blood cell counts in the bloodstream can be normal or low. Aleukemia can occur in any of the four major types of leukemia, and is particularly common in hairy cell leukemia.

Treatment :


Most forms of leukemia are treated with pharmaceutical medications. Some are also treated with radiation therapy. In some cases, a bone marrow transplant is useful.

DIABETES

Diabetes is a disease that affects the way the body digests food. A healthy body will digest food and convert it into glucose, a chemical that fuels the cells of the body. A hormone called insulin is essential to this process. Insulin is needed in order for the body to have the energy it needs to grow and stay healthy. People with diabetes are unable to produce, or efficiently use, insulin.
Diabetes can come in two forms: type I diabetes (which is usually diagnosed in children and teenagers), and type II diabetes (which is usually diagnosed in adults). The causes of both types of diabetes are still unknown, however, type I is though to have genetic causes while type II is more strongly linked to lifestyle factors such as obesity, lack of exercise and poor diet. Being of African American, Hispanic American, American Indian, Native Hawaiian or some Pacific Island descent also increases the risk for type II diabetes. Neither form of diabetes is contagious: you cannot catch diabetes from another person.

Overview of Diabetes

A chronic condition that results from deficiencies in the body's ability to produce or use insulin, which is a substance that keeps blood sugar levels stable.
Children and adults can develop diabetes.
There may be an inherited factor, but diet and lifestyle - high fat, low fiber diet, lack of physical exercise - may trigger the condition as well.
In 2000, 171 MILLION people worldwide suffered from diabetes. This is expected to be 366 MILLION by 2030 - mainly due to a huge rise in the numbers in African and Asian countries.
It is a very serious condition and is life-threatening. However, with early diagnosis and good management, people can live for a long time with diabetes.

SYMPTOMS OF DIABETES :

Frequent urination
Excessive thirst/hunger
Tiredness
Blurry vision

If people have these symptoms, they should go to the doctor to get tested for diabetes. Then the doctor and other health care providers can help the person to manage the disease to prevent complications.

COMPLICATIONS OF DIABETES

Heart attack and stroke
Kidney disease

Lower limb removal
Eye diseases and blindness

SYMPTOMS OF EYE DISEASE

Diabetes can result in blindness due to:
Glaucoma - when liquid pressure builds up in the eye;
Cataracts - the lens of the eye gets cloudy;
Diabetic retinopathy - where the blood vessels at the back of he eye become weak and burst
An important point is that a person may already have the beginning stages of diabetic retinopathy without knowing it, as it does not affect vision in the early onset.

Diabetic Retina normal ratina

New Blood Vessel Growth

Treatment and management :

Diabetes mellitus is currently a chronic disease with no cure. Medical emphasis must necessarily be on managing/avoiding possible short-term as well as long-term diabetes-related problems. There is an exceptionally important role for patient education, dietetic support, sensible exercise, self monitoring of blood glucose, with the goal of keeping both short-term and long-term blood glucose levels within acceptable bounds. Careful control is needed to reduce the risk of long term complications. This is theoretically achievable with combinations of diet, exercise and weight loss (type 2), various oral diabetic drugs (type 2 only), and insulin use (type 1 and for type 2 not responding to oral medications, mostly those with extended duration diabetes). In addition, given the associated higher risks of cardiovascular disease, lifestyle modifications should be undertaken to control blood pressure and cholesterol by exercising more, smoking less or ideally not at all, consuming an appropriate diet, wearing diabetic socks, wearing diabetic shoes, and if necessary, taking any of several drugs to reduce blood pressure. Many type 1 treatments include combination use of regular or NPH insulin, and/or synthetic insulin analogs (e.g., Humalog, Novolog or Apidra) in combinations such as Lantus/Levemir and Humalog, Novolog or Apidra. Another type 1 treatment option is the use of the insulin pump (e.g., from Deltec Cozmo, Animas, Medtronic Minimed, Insulet Omnipod, or ACCU-CHEK). A blood lancet is used to pierce the skin (typically of a finger), in order to draw blood to test it for sugar levels.
In countries using a general practitioner system, such as the United Kingdom, care may take place mainly outside hospitals, with hospital-based specialist care used only in case of complications, difficult blood sugar control, or research projects. In other circumstances, general practitioners and specialists share care of a patient in a team approach. Optometrists, podiatrists/chiropodists, dietitians, physiotherapists, nursing specialists (e.g., DSNs (Diabetic Specialist Nurse)), nurse practitioners, or Certified Diabetes Educators, may jointly provide multidisciplinary expertise. In countries where patients must provide for their own health care (e.g in the US, and in much of the undeveloped world), the impact of out-of-pocket costs of adequate diabetic care can be very high. In addition to the medications and supplies needed, patients are often advised to receive regular consultation from a physician (e.g., at least every three to six months) although research is underway to develop artificial intelligence systems which may reduce the frequency of such visits.
Oral administration of aloe vera might be a useful adjunct for lowering blood glucose in diabetic patients as well as for reducing blood lipid levels in patients with hyperlipidaemia. Ten controlled clinical trials were found to reach that conclusion in four independent literature searches. However, caveats reported in each study led the researchers to conclude that aloe vera's clinical effectiveness was not yet sufficiently defined in 1999.
Peer support links people living with diabetes. Within peer support, people with a common illness share knowledge and experience that others, including many health workers, do not have. Peer support is frequent, ongoing, accessible and flexible and can take many forms—phone calls, text messaging, group meetings, home visits, and even grocery shopping. It complements and enhances other health care services by creating the emotional, social and practical assistance necessary for managing disease and staying healthy.

MALARIA

MALARIA :

Malaria is a vector-borne infectious disease caused by a eukaryotic protist of the genus Plasmodium. It is widespread in tropical and subtropical regions, including parts of the Americas, Asia, and Africa. Each year, there are approximately 350–500 million cases of malaria, killing between one and three million people, the majority of whom are young children in Sub-Saharan Africa. Ninety percent of malaria-related deaths occur in Sub-Saharan Africa. Malaria is commonly associated with poverty, but is also a cause of poverty and a major hindrance to economic development.
Malaria is one of the most common infectious diseases and an enormous public health problem. Five species of the plasmodium parasite can infect humans; the most serious forms of the disease are caused by Plasmodium falciparum. Malaria caused by Plasmodium vivax, Plasmodium ovale and Plasmodium malariae causes milder disease in humans that is not generally fatal. A fifth species, Plasmodium knowlesi, causes malaria in macaques but can also infect humans. This group of human-pathogenic Plasmodium species is usually referred to as malaria parasites.
Usually, people get malaria by being bitten by an infective female Anopheles mosquito. Only Anopheles mosquitoes can transmit malaria, and they must have been infected through a previous blood meal taken on an infected person. When a mosquito bites an infected person, a small amount of blood is taken, which contains microscopic malaria parasites. About one week later, when the mosquito takes its next blood meal, these parasites mix with the mosquito's saliva and are injected into the person being bitten. The parasites multiply within red blood cells, causing symptoms that include symptoms of anemia (light-headedness, shortness of breath, tachycardia, etc.), as well as other general symptoms such as fever, chills, nausea, flu-like illness, and, in severe cases, coma, and death. Malaria transmission can be reduced by preventing mosquito bites with mosquito nets and insect repellents, or by mosquito control measures such as spraying insecticides inside houses and draining standing water where mosquitoes lay their eggs. Work has been done on malaria vaccines with limited success and more exotic controls, such as genetic manipulation of mosquitoes to make them resistant to the parasite have also been considered.
Although some are under development, no vaccine is currently available for malaria that provides a high level of protection; preventive drugs must be taken continuously to reduce the risk of infection. These prophylactic drug treatments are often too expensive for most people living in endemic areas. Most adults from endemic areas have a degree of long-term infection, which tends to recur, and also possess partial immunity (resistance); the resistance reduces with time, and such adults may become susceptible to severe malaria if they have spent a significant amount of time in non-endemic areas. They are strongly recommended to take full precautions if they return to an endemic area. Malaria infections are treated through the use of antimalarial drugs, such as quinine or artemisinin derivatives. However, parasites have evolved to be resistant to many of these drugs. Therefore, in some areas of the world, only a few drugs remain as effective treatments for malaria.

Symptoms :

Symptoms of malaria include fever, shivering, arthralgia (joint pain), vomiting, anemia (caused by hemolysis), hemoglobinuria, retinal damage, and convulsions. The classic symptom of malaria is cyclical occurrence of sudden coldness followed by rigor and then fever and sweating lasting four to six hours, occurring every two days in P. vivax and P. ovale infections, while every three for P. malariae. P. falciparum can have recurrent fever every 36–48 hours or a less pronounced and almost continuous fever. For reasons that are poorly understood, but that may be related to high intracranial pressure, children with malaria frequently exhibit abnormal posturing, a sign indicating severe brain damage. Malaria has been found to cause cognitive impairments, especially in children. It causes widespread anemia during a period of rapid brain development and also direct brain damage. This neurologic damage results from cerebral malaria to which children are more vulnerable. Cerebral malaria is associated with retinal whitening,which may be a useful clinical sign in distinguishing it from other causes of fever.

Severe malaria is almost exclusively caused by P. falciparum infection and usually arises 6–14 days after infection. Consequences of severe malaria include coma and death if untreated—young children and pregnant women are especially vulnerable. Splenomegaly (enlarged spleen), severe headache, cerebral ischemia, hepatomegaly (enlarged liver), hypoglycemia, and hemoglobinuria with renal failure may occur. Renal failure may cause blackwater fever, where hemoglobin from lysed red blood cells leaks into the urine. Severe malaria can progress extremely rapidly and cause death within hours or days. In the most severe cases of the disease fatality rates can exceed 20%, even with intensive care and treatment. In endemic areas, treatment is often less satisfactory and the overall fatality rate for all cases of malaria can be as high as one in ten. Over the longer term, developmental impairments have been documented in children who have suffered episodes of severe malaria.
Chronic malaria is seen in both P. vivax and P. ovale, but not in P. falciparum. Here, the disease can relapse months or years after exposure, due to the presence of latent parasites in the liver. Describing a case of malaria as cured by observing the disappearance of parasites from the bloodstream can, therefore, be deceptive. The longest incubation period reported for a P. vivax infection is 30 years. Approximately one in five of P. vivax malaria cases in temperate areas involve overwintering by hypnozoites (i.e., relapses begin the year after the mosquito bite).

Causes :

Malaria parasites are members of the genus Plasmodium (phylum Apicomplexa). In humans malaria is caused by P. falciparum, P. malariae, P. ovale, P. vivax and P. knowlesi. P. falciparum is the most common cause of infection and is responsible for about 80% of all malaria cases, and is also responsible for about 90% of the deaths from malaria. Parasitic Plasmodium species also infect birds, reptiles, monkeys, chimpanzees and rodents. There have been documented human infections with several simian species of malaria, namely P. knowlesi, P. inui, P. cynomolgi, P. simiovale, P. brazilianum, P. schwetzi and P. simium; however, with the exception of P. knowlesi, these are mostly of limited public health importance.Although avian malaria can kill chickens and turkeys, this disease does not cause serious economic losses to poultry farmers. However, since being accidentally introduced by humans it has decimated the endemic birds of Hawaii, which evolved in its absence and lack any resistance to it.

Vaccination :

Immunity (or, more accurately, tolerance) does occur naturally, but only in response to repeated infection with multiple strains of malaria.
Vaccines for malaria are under development, with no completely effective vaccine yet available. The first promising studies demonstrating the potential for a malaria vaccine were performed in 1967 by immunizing mice with live, radiation-attenuated sporozoites, providing protection to about 60% of the mice upon subsequent injection with normal, viable sporozoites. Since the 1970s, there has been a considerable effort to develop similar vaccination strategies within humans. It was determined that an individual can be protected from a P. falciparum infection if they receive over 1,000 bites from infected, irradiated mosquitoes.
It has been generally accepted that it is impractical to provide at-risk individuals with this vaccination strategy, but that has been recently challenged with work being done by Dr. Stephen Hoffman, one of the key researchers who originally sequenced the genome of Plasmodium falciparum. His work most recently has revolved around solving the logistical problem of isolating and preparing the parasites equivalent to 1000 irradiated mosquitoes for mass storage and inoculation of human beings. The company has recently received several multi-million dollar grants from the Bill & Melinda Gates Foundation and the U.S. government to begin early clinical studies in 2007 and 2008. The Seattle Biomedical Research Institute (SBRI), funded by the Malaria Vaccine Initiative, assures potential volunteers that "the [2009] clinical trials won't be a life-threatening experience. While many volunteers [in Seattle] will actually contract malaria, the cloned strain used in the experiments can be quickly cured, and does not cause a recurring form of the disease." "Some participants will get experimental drugs or vaccines, while others will get placebo."
Instead, much work has been performed to try and understand the immunological processes that provide protection after immunization with irradiated sporozoites. After the mouse vaccination study in 1967, it was hypothesized that the injected sporozoites themselves were being recognized by the immune system, which was in turn creating antibodies against the parasite. It was determined that the immune system was creating antibodies against the circumsporozoite protein (CSP) which coated the sporozoite. Moreover, antibodies against CSP prevented the sporozoite from invading hepatocytes. CSP was therefore chosen as the most promising protein on which to develop a vaccine against the malaria sporozoite. It is for these historical reasons that vaccines based on CSP are the most numerous of all malaria vaccines.
Presently, there is a huge variety of vaccine candidates on the table. Pre-erythrocytic vaccines (vaccines that target the parasite before it reaches the blood), in particular vaccines based on CSP, make up the largest group of research for the malaria vaccine. Other vaccine candidates include: those that seek to induce immunity to the blood stages of the infection; those that seek to avoid more severe pathologies of malaria by preventing adherence of the parasite to blood venules and placenta; and transmission-blocking vaccines that would stop the development of the parasite in the mosquito right after the mosquito has taken a bloodmeal from an infected person. It is hoped that the sequencing of the P. falciparum genome will provide targets for new drugs or vaccines.
The first vaccine developed that has undergone field trials, is the SPf66, developed by Manuel Elkin Patarroyo in 1987. It presents a combination of antigens from the sporozoite (using CS repeats) and merozoite parasites. During phase I trials a 75% efficacy rate was demonstrated and the vaccine appeared to be well tolerated by subjects and immunogenic. The phase IIb and III trials were less promising, with the efficacy falling to between 38.8% and 60.2%. A trial was carried out in Tanzania in 1993 demonstrating the efficacy to be 31% after a years follow up, however the most recent (though controversial) study in The Gambia did not show any effect. Despite the relatively long trial periods and the number of studies carried out, it is still not known how the SPf66 vaccine confers immunity; it therefore remains an unlikely solution to malaria. The CSP was the next vaccine developed that initially appeared promising enough to undergo trials. It is also based on the circumsporoziote protein, but additionally has the recombinant (Asn-Ala-Pro15Asn-Val-Asp-Pro)2-Leu-Arg(R32LR) protein covalently bound to a purified Pseudomonas aeruginosa toxin (A9). However at an early stage a complete lack of protective immunity was demonstrated in those inoculated. The study group used in Kenya had an 82% incidence of parasitaemia whilst the control group only had an 89% incidence. The vaccine intended to cause an increased T-lymphocyte response in those exposed, this was also not observed.
The efficacy of Patarroyo's vaccine has been disputed with some US scientists concluding in The Lancet (1997) that "the vaccine was not effective and should be dropped" while the Colombian accused them of "arrogance" putting down their assertions to the fact that he came from a developing country.
The RTS,S/AS02A vaccine is the candidate furthest along in vaccine trials. It is being developed by a partnership between the PATH Malaria Vaccine Initiative (a grantee of the Gates Foundation), the pharmaceutical company, GlaxoSmithKline, and the Walter Reed Army Institute of Research In the vaccine, a portion of CSP has been fused to the immunogenic "S antigen" of the hepatitis B virus; this recombinant protein is injected alongside the potent AS02A adjuvant. In October 2004, the RTS,S/AS02A researchers announced results of a Phase IIb trial, indicating the vaccine reduced infection risk by approximately 30% and severity of infection by over 50%. The study looked at over 2,000 Mozambican children. More recent testing of the RTS,S/AS02A vaccine has focused on the safety and efficacy of administering it earlier in infancy: In October 2007, the researchers announced results of a phase I/IIb trial conducted on 214 Mozambican infants between the ages of 10 and 18 months in which the full three-dose course of the vaccine led to a 62% reduction of infection with no serious side-effects save some pain at the point of injection. Further research will delay this vaccine from commercial release until around 2011

Treatment :

Active malaria infection with P. falciparum is a medical emergency requiring hospitalization. Infection with P. vivax, P. ovale or P. malariae can often be treated on an outpatient basis. Treatment of malaria involves supportive measures as well as specific antimalarial drugs. When properly treated, someone with malaria can expect a complete recovery

TUBERCULOSIS ( TB )

TUBERCULOSIS

Tuberculosis (abbreviated TB, which can also stand for tubercle bacillus) is a common and often deadly infectious disease caused by mycobacteria. In humans, Mycobacterium tuberculosis is the primary causative bacterium although other mycobacteria such as Mycobacterium bovis, Mycobacterium africanum, Mycobacterium canetti, and Mycobacterium microti are also causes. Tuberculosis usually attacks the lungs (as pulmonary TB) but can also affect the central nervous system, the lymphatic system, the circulatory system, the genitourinary system, the gastrointestinal system, bones, joints, and even the skin.
Tuberculosis is spread through the air, when people who have the disease cough, sneeze, or spit. Most infections in human beings will result in asymptomatic, latent infection, and about one in ten latent infections will eventually progress to active disease, which, if left untreated, kills more than half of its victims. The classic symptoms of tuberculosis are a chronic cough with blood-tinged sputum, fever, night sweats, and weight loss. Infection of other organs causes a wide range of symptoms.
The diagnosis relies on radiology (commonly chest X-rays), a tuberculin skin test, blood tests, as well as microscopic examination and microbiological culture of bodily fluids. Tuberculosis treatment is difficult and requires long courses of multiple antibiotics. Contacts are also screened and treated if necessary. Antibiotic resistance is a growing problem in (extensively) multi-drug-resistant tuberculosis. Prevention relies on screening programs and vaccination, usually with Bacillus Calmette-Guérin (BCG vaccine).
One–third of the world's current population has been infected with M. tuberculosis. New infections occur at a rate of one per second. The proportion of people in the general population who become sick with tuberculosis each year is stable or falling worldwide but, because of population growth, the absolute number of new cases is still increasing.
In 2004, mortality and morbidity statistics included 14.6 million chronic active cases, 8.9 million new cases, and 1.6 million deaths, mostly in developing countries. In addition, a rising number of people in the developed world are contracting tuberculosis because their immune systems are compromised by immunosuppressive drugs, substance abuse, or AIDS. The distribution of tuberculosis is not uniform across the globe; about 80% of the population in many Asian and African countries test positive in tuberculin tests, while only 5-10% of the US population test positive. It is estimated that the US has 25,000 new cases of tuberculosis each year, 40% of which occur in immigrants from countries where tuberculosis is endemic.

Signs and symptoms

When the disease becomes active, 75% of the cases are pulmonary TB. Symptoms include chest pain, coughing up blood, and a productive, prolonged cough for more than three weeks. Systemic symptoms include fever, chills, night sweats, appetite loss, weight loss, pallor, and often a tendency to fatigue very easily.
In the other 25% of active cases, the infection moves from the lungs, causing other kinds of TB, collectively denoted extrapulmonary tuberculosis. This occurs more commonly in immunosuppressed persons and young children. Extrapulmonary infection sites include the pleura in tuberculosis pleurisy, the central nervous system in meningitis, the lymphatic system in scrofula of the neck, the genitourinary system in urogenital tuberculosis, and bones and joints in Pott's disease of the spine. An especially serious form is disseminated TB, more commonly known as miliary tuberculosis. Extrapulmonary TB may co-exist with pulmonary TB as well.

Causes

The primary cause of TB, Mycobacterium tuberculosis, is an aerobic bacterium that divides every 16 to 20 hours, an extremely slow rate compared with other bacteria, which usually divide in less than an hour. (For example, one of the fastest-growing bacteria is a strain of E. coli that can divide roughly every 20 minutes.) Since MTB has a cell wall but lacks a phospholipid outer membrane, it is classified as a Gram-positive bacterium. However, if a Gram stain is performed, MTB either stains very weakly Gram-positive or does not retain dye due to the high lipid & mycolic acid content of its cell wall. MTB is a small rod-like bacillus that can withstand weak disinfectants and survive in a dry state for weeks. In nature, the bacterium can grow only within the cells of a host organism, but M. tuberculosis can be cultured in vitro

Using histological stains on expectorate samples from phlegm (also called sputum), scientists can identify MTB under a regular microscope. Since MTB retains certain stains after being treated with acidic solution, it is classified as an acid-fast bacillus (AFB). The most common acid-fast staining technique, the Ziehl-Neelsen stain, dyes AFBs a bright red that stands out clearly against a blue background. Other ways to visualize AFBs include an auramine-rhodamine stain and fluorescent microscopy.
The M. tuberculosis complex includes three other TB-causing mycobacteria: M. bovis, M. africanum, and M. microti. M. africanum is not widespread, but in parts of Africa it is a significant cause of tuberculosis. M. bovis was once a common cause of tuberculosis, but the introduction of pasteurized milk has largely eliminated this as a public health problem in developed countries. M. microti is mostly seen in immunodeficient people, although it is possible that the prevalence of this pathogen has been underestimated.Other known pathogenic mycobacteria include Mycobacterium leprae, Mycobacterium avium and M. kansasii. The last two are part of the nontuberculous mycobacteria (NTM) group. Nontuberculous mycobacteria cause neither TB nor leprosy, but they do cause pulmonary diseases resembling TB.

Prevention

TB prevention and control takes two parallel approaches. In the first, people with TB and their contacts are identified and then treated. Identification of infections often involves testing high-risk groups for TB. In the second approach, children are vaccinated to protect them from TB. Unfortunately, no vaccine is available that provides reliable protection for adults. However, in tropical areas where the levels of other species of mycobacteria are high, exposure to nontuberculous mycobacteria gives some protection against TB.
The World Health Organization (W.H.O.) declared TB a global health emergency in 1993, and the Stop TB Partnership developed a Global Plan to Stop Tuberculosis that aims to save 14 million lives between 2006 and 2015. Since humans are the only host of Mycobacterium tuberculosis, eradication would be possible: a goal that would be helped greatly by an effective vaccine.

Vaccines

Many countries use Bacillus Calmette-Guérin (BCG) vaccine as part of their TB control programs, especially for infants. According to the W.H.O., this is the most often used vaccine worldwide, with 85% of infants in 172 countries immunized in 1993. This was the first vaccine for TB and developed at the Pasteur Institute in France between 1905 and 1921. However, mass vaccination with BCG did not start until after World War II. The protective efficacy of BCG for preventing serious forms of TB (e.g. meningitis) in children is greater than 80%; its protective efficacy for preventing pulmonary TB in adolescents and adults is variable, ranging from 0 to 80%.
In South Africa, the country with the highest prevalence of TB, BCG is given to all children under age three. However, BCG is less effective in areas where mycobacteria are less prevalent; therefore BCG is not given to the entire population in these countries. In the USA, for example, BCG vaccine is not recommended except for people who meet specific criteria:
Infants or children with negative skin test results who are continually exposed to untreated or ineffectively treated patients or will be continually exposed to multidrug-resistant TB. Healthcare workers considered on an individual basis in settings in which a high percentage of MDR-TB patients has been found, transmission of MDR-TB is likely, and TB control precautions have been implemented and were not successful. BCG provides some protection against severe forms of pediatric TB, but has been shown to be unreliable against adult pulmonary TB, which accounts for most of the disease burden worldwide. Currently, there are more cases of TB on the planet than at any other time in history and most agree there is an urgent need for a newer, more effective vaccine that would prevent all forms of TB—including drug resistant strains—in all age groups and among people with HIV.
Several new vaccines to prevent TB infection are being developed. The first recombinant tuberculosis vaccine rBCG30, entered clinical trials in the United States in 2004, sponsored by the National Institute of Allergy and Infectious Diseases (NIAID). A 2005 study showed that a DNA TB vaccine given with conventional chemotherapy can accelerate the disappearance of bacteria as well as protect against re-infection in mice; it may take four to five years to be available in humans. A very promising TB vaccine, MVA85A, is currently in phase II trials in South Africa by a group led by Oxford University, and is based on a genetically modified vaccinia virus. Many other strategies are also being used to develop novel vaccines, including both subunit vaccines (fusion molecules composed of two recombinant proteins delivered in an adjuvant) such as Hybrid-1, HyVac4 or M72, and recombinant adenoviruses such as Ad35. Some of these vaccines can be effectively administered without needles, making them preferable for areas where HIV is very common. All of these vaccines have been successfully tested in humans and are now in extended testing in TB-endemic regions. In order to encourage further discovery, researchers and policymakers are promoting new economic models of vaccine development including prizes, tax incentives and advance market commitments.
The Bill and Melinda Gates Foundation has been a strong supporter of new TB vaccine development. Most recently, it announced a $200 million grant to the Aeras Global TB Vaccine Foundation for clinical trials on up to six different TB vaccine candidates currently in the pipeline

Treatment

Treatment for TB uses antibiotics to kill the bacteria. The two antibiotics most commonly used are rifampicin and isoniazid. However, instead of the short course of antibiotics typically used to cure other bacterial infections, TB requires much longer periods of treatment (around 6 to 12 months) to entirely eliminate mycobacteria from the body. Latent TB treatment usually uses a single antibiotic, while active TB disease is best treated with combinations of several antibiotics, to reduce the risk of the bacteria developing antibiotic resistance. People with latent infections are treated to prevent them from progressing to active TB disease later in life.
Drug resistant tuberculosis is transmitted in the same way as regular TB. Primary resistance occurs in persons who are infected with a resistant strain of TB. A patient with fully susceptible TB develops secondary resistance (acquired resistance) during TB therapy because of inadequate treatment, not taking the prescribed regimen appropriately, or using low quality medication. Drug-resistant TB is a public health issue in many developing countries, as treatment is longer and requires more expensive drugs. Multi-drug-resistant tuberculosis (MDR-TB) is defined as resistance to the two most effective first-line TB drugs: rifampicin and isoniazid. Extensively drug-resistant TB (XDR-TB) is also resistant to three or more of the six classes of second-line drugs. The DOTS (Directly Observed Treatment Short-course) strategy of tuberculosis treatment recommended by WHO was based on clinical trials done in the 1970s by Tuberculosis Research Centre, Chennai, India.