By Tracey Archer
The first reported case of Mycobacterium tuberculosis (TB) can be dated back to as early as 2400BC, but it was not until 1991 that the first global efforts to reduce TB were implemented. Tubercle bacilli is responsible for 1.7 million global deaths per yearIn 1991 the world health advocacy (WHA) declared TB a global health issue and and1994 the world health organization placed together a strategy called DOTS (direct observation therapy short-course), 184 countries participated in the DOTS program. By 2003, treatment goals were almost at the target range set by WHO which were detection of 70% of all smear-positive cases and cure of 85% of these casesstatistics showed that the DOTS program was yielding results a good 20% lower than the anticipated cure goal of 85%. This lead to an expansion of DOTS strategy in 2005 which went hand in hand with the 2006 implementation of a new strategy named the “Stop TB” strategy which focused on the expansion of DOTS as well as ‘substantial financing’ which would boost global treatment efforts
Both strategies’ involved the cooperation of Global bodies, the use of the BCG vaccine as well as antibiotics specific for the treatment of tuberculosis and an understanding of the disease states, both infectious and non infectious, latent TB and active Tb as well as MDR-TB ( multi-drug resistant TB ) and XDR- TB, (strains of TB resistant to more then one of the second line of TB medicationThe Stop TB strategy also takes into account financing, outreach programs thus increasing the number of people that access the programs and research opportunities that can lead to future developmentsThe efficiency of these strategies was examined by the global impact of vaccines old and new as well as antibiotic treatment for each strain of TB. Past and present global efforts to reduce TB were only effective when working as one and looking into the future possibilities. For over 80 years the BCG vaccine has been used as a preventative measure against tuberculosis. BCG itself is only produced in a few laboratories around the worldthen the vaccine must be transported to other countries raising the cost of the treatment. BCG can be stored in a powder form but upon preparation sterile water is required, in some instances water must be transported with the vaccine. BCG must be then used within 2-3 hours post preparation and all BCG vaccines need to be kept in a climate of at least 6-8 degrees Celsius in freezers’or fridges BCG vaccine has proven to be effective against the spread of childhood tuberculosis by providing children with an acquired immunitythis immunity can last about 15years however does not protect from Adult tuberculosis. Future possible vaccines for TB as at 2001.
vaccine
| vaccine | Number of cases | example |
| Avirulent sapro-phytes | 4 5 | myobacterium vaccae myobacterium microti |
| Autotrophs | 9 | Mycobacterium smegmatis Mycobacterium tuberculosis |
| Recombinants | 20 | BCG |
| Subunits | 83 | Culture filtrates,Individual proteins,Protein mixtures Fusion proteins |
| DNA vaccine | 33 | Ag 85 HSP60 |
| Mutantsans others/ fusions | 5/11 |
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Advances in a new TB vaccine is most likely going to come from studies into the Culture filtrates, Individual proteins, Protein mixtures and Fusion proteins. In 2001 the biggest problem in the development of new vaccines was funding. Treatment for TB infected patients depends on the strain of the diseaseAntibiotics is both a past and present treatment as Mycobacterium tuberculosis. In 1945 the development of streptomycin (SM) proved to be the first break through in therapy followed by Ioniazid (INH) in 1952. Other modern day antibiotics that are used include rifampin (Rifadin, Rimactane), ethambutol (Myambutol) and pyrazinamide. Different types of TB require different medicationsLatent TB (LTB) is an area that must be addressed if reduction in TB globally is going to be achieved. Latent TB is not symptomatic but affects around 9 billon people world widetreatment requires one primary Antibiotic over 4-9 monthsActive TB requires the administration of a mixture of antibiotics usually four at once the most commonly prescribed meds are Isoniazid, rifampin (Rifadin, Rimactane, ethambutol (Myambutol)and pyrazinamide however these drugs sometimes can have no effect suggesting that the strain of TB present in the patient is resistant to the antibiotics these patients are then recognized as having MDR-TB( multi drug resistant TB).
MDR-TB( multi drug resistant TB).is defined when two or more of the first line drugs have no effect. Physicians then prescribe 2nd line defence drug such as rifapine, streptomycin, ethionamide and cyclosserine as well as new Antituberculosis drugs such as the fluoroquinolones, PA 824 and the diarylquinoline R207910in addition other treatments may be required such as Pulmonary resection, this treatment has been proven to be effectiveThere are about 300.000 cases of muti drug resistant Tb reported annuallyand 10% of these cases have been resistant to 3 or more antibiotics from the second line of defence. This resistant Tb strain is known as XDR-TB(Extensively Drug-resistant Tuberculosis)
XDR-TB has emerged due to inadequate treatment and or non compliance to treatment. It is defined by its resistance to 1st line Tb antibiotics and injectable 2nd line Antibiotics. Treatment usually consists of a mixture of 2nd line antibiotics, and possible surgery
Some strains of TB have developed that can not be matched with the XDR-TB definition indicating that new antibiotics must be developed if the Global eradication of TB is likely to succeed). XDR-TB accounts for about 10% of MDR-TB cases and when associated with the ever rising HIV epidemic some patients with XDR-TB have no options left , unfortunately if new drugs are no produced to fight this XDR-TB then the world may be on the edge of an untreatable epidemic therefore the statement that The world is a safer [place with the advent of a new vaccine against tuberculosis is indeed a needed state mment and the fact that travelers are warned to continue boiling water and avoiding contact with mosquito-infested water” is always good advice especially with the every changing strains of TB and the past ineffectiveness of current vaccines.
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