Eventual Control And Eradication Biology Essay

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Despite massive efforts around the world to curb the tide of tuberculosis, with the intent of eventual control and eradication of the disease, this particular bacterial infection continues to rise in prevalence. In most higher income countries where testing and treatment are readily available, tuberculosis is no longer the concern it once was. However, while prevalence of this disease remains stable or falls in wealthier countries, worldwide numbers continue to increase (Maartens 2007). This general increase in the number of cases can largely be attributed to the region of Sub-Saharan Africa, where the frequency of HIV coupled with resource poor healthcare systems, results in a much higher level of susceptibility for individuals residing there (Maartens 2007). This fact exemplifies the current limitations of prevention, rapid cheap diagnostic testing, and eventual treatment of the disease. To stem this tide, the authors of Tuberculosis, Gary Maartens and Robert Wilkinson, suggest that health organizations around the world must work coordinately and with all available advances in understanding and treatment of this disease to finally place it under control.

Recent advances in our understanding of tuberculosis, both genetically and in how it reacts with the immune system, are providing new insights in how to prevent, manage, and treat the disease. Due to the ease of manipulation in a lab setting of the bacteria responsible for tuberculosis, Mycobacterium tuberculosis, it has become a more common target for bacterial genomics studies (Maartens 2007). As a result of these studies a better understanding of how mycobacterium infect host cells has been determined, thus allowing new possible avenues of treatment. In one such study it was determined that something as simple as activated vitamin D has "pleiotropic immune effects, including the induction of antimicrobial peptides such as the cathelicidin LL-37" (Maartens 2007). This, in conjunction with an observation showing a deficiency of vitamin D associated with tuberculosis, yields a "possibility of prevention of tuberculosis by vitamin D supplements" (Maartens 2007). If found to be true this would indicate a simple, cost effective method for additional prevention of tuberculosis infection. A separate study cited in the article identifies important characteristics of mycobacteria early in infection. It was found that, early on in infection, the rapid aerobic growth of mycobacteria was dependant on carbohydrates. It was also found that the bacteria could change later on in infection to using lipids as a source of energy (Maartens 2007). Perhaps more importantly, it was shown in two studies the "kefB, a K+ efflux channel, protects bacilli against electrophile toxic effects by lowering intracellular pH" (Maartens 2007). This discovery hints at a possible target for new antimycobacterial drugs, which are becoming increasingly important as multidrug resistant tuberculosis becomes more prevalent.

Another hurdle facing resource poor healthcare providers of patients with tuberculosis in addition to HIV is the need of a cheap, rapidly diagnostic test. Rapid diagnosis can greatly aid in the successful treatment of both active and latent tuberculosis. It is also important to quickly identify multidrug resistance, as a different course of treatment is required. Currently, among the most inexpensive tests to identify mycobacteria is the acid-fast microscopy stain, but this is not as reliable as other, newer, much more expensive methods. The need for a cheap test that is not affected by the presence of HIV has resulted in several promising new tests. Three studies that used antigen-based tests are cited in the article as having led to the currently commercially available T.SPOT.TB test, which shows promise for use but still needs more testing (Maartens 2007). Equally important is a test that can quickly show multidrug resistant tuberculosis in an infected patient. As this requires a different drug regimen, it is beneficial to identify drug resistance more quickly than the 6-8 weeks it takes using conventional methods (Maartens 2007). One such test identified in the article involves "microscopic examination of growth wells that are filled with liquid culture medium, with or without drugs" (Maartens 2007), which allows for identification within 10 days.

Treatment for tuberculosis has remained the same for years and involves giving a combination of isoniazid, rifampicin, pyrazinamide, and ethambutol for two months followed by four months of isoniazid and rifampicin (Maartens 2007). Immediately evident is the lengthy amount of time required for treatment of tuberculosis, which is a problem in resource limited areas such as Sub-Saharan Africa. Typical administration of the drugs involves the direct observation of patients while they take the medications to ensure that they follow through the entire regimen for the required amount of time, which is a cost-effective plan in lower income regions. However, multidrug resistance commonly arises, in addition to relapse, as "many patients discontinue treatment when their symptoms improve" (Maartens 2007). More effective medications that do not require such a lengthy course of treatment could possibly improve the outcome of treatment in these areas. One such group of medications mentioned were the fluoroquinolones which, while still requiring more testing, show promise in the treatment of tuberculosis (Maartens 2007). One major problem with treatment of HIV patients that also have either active or latent tuberculosis is that drug interactions between tuberculosis medications and antivirals have not been well studied. Also, many antitubercular drugs have shown varying levels of hepatotoxicity in patients, adding to the need for newer alternatives for treatment and prevention (Maartens 2007). Vaccinations would also be greatly beneficial in the control of the disease, however the most effective vaccine currently available provides only moderate protection (Maartens 2007). The authors suggest however, that vaccination after infection could provide some protection against reactivation of the disease, but more testing is needed.

As stated early in the article, tuberculosis has been a leading killer throughout human history. While advanced nations have seen falling rates of disease associated with M. tuberculosis it continues to be a major problem for underdeveloped countries. Options in these regions are limited as cost prohibits many of the recent advances in treatment and prevention from being used. I agree that, with the increasing incidence of multidrug resistant tuberculosis, the threat of this disease is nowhere near going away. The strategies discussed by the authors are sound and the ever-increasing advances in our understanding of this disease provide hope for the future. However, despite the success seen in many regions of the world with the direct observation strategy of treatment, Sub-Saharan Africa faces a more unique and daunting challenge due to the HIV epidemic. As mentioned in the article "the only preventive strategy that substantially affected incidence of tuberculosis was reduced HIV incidence" (Maartens 2007). This causes the largest problem facing our control of tuberculosis, as the best way to control it is by prevention. As long as HIV remains so prevalent in the region tuberculosis will remain a problem. Only with a coordinated effort by the international health community can we expect to provide the needed medications, diagnostic tools, healthcare personnel, and education of the regions populace in prevention of both HIV and tuberculosis. If these efforts can be achieved, tuberculosis will cease to be the threat it has been throughout our history.