Treatment of MDR-TB requires second-line drugs (i.e., fluoroquinolones, aminoglycosides, and others), which in general are less effective, more toxic and much more expensive than first-line drugs. Treatment schedules for MDR-TB involving fluoroquinolones and aminoglycosides can run for 2 years, compared to the 6 months of first-line drug treatment, and cost over US$100,000. If these second-line drugs are prescribed or taken incorrectly, further resistance can develop leading to XDR-TB. Resistant strains of TB are already present in the population, so MDR-TB can be directly transmitted from an infected person to an uninfected person. In this case a previously untreated person develops a new case of MDR-TB. This is known as primary MDR-TB, and is responsible for up to 75% of cases. Acquired MDR-TB develops when a person with a non-resistant strain of TB is treated inadequately, resulting in the development of antibiotic resistance in the TB bacteria infecting them. These people can in turn infect other people with MDR-TB.MDR-TB caused an estimated 600,000 new TB cases and 240,000 deaths in 2016 and MDR-TB accounts for 4.1% of all new TB cases and 19% of previously treated cases worldwide. Globally, most MDR-TB cases occur in South America, Southern Africa, India, China, and the former Soviet Union.Treatment of MDR-TB requires treatment with second-line drugs, usually four or more anti-TB drugs for a minimum of 6 months, and possibly extending for 18–24 months if rifampin resistance has been identified in the specific strain of TB with which the patient has been infected.
The efficacy was about 30% in infants 6 to 12 weeks of age and about 50% in infants 5 to 17 months of age in the first year of the trial.The RTS,S vaccine was engineered using a fusion hepatitis B surface protein containing epitopes of the outer protein of Plasmodium falciparum malaria sporozite, which is produced in yeast cells. It also contains a chemical adjuvant to boost the immune system response. The vaccine is being developed by PATH and GlaxoSmithKline (GSK), which has spent about $300 million on the project, plus about $200 million more from the Bill and Melinda Gates Foundation. Risk factors
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. History
Malaria is one of the oldest known pathogens, and began having a major impact on human survival about 10,000 years ago with the birth of agriculture. The development of virulence in the parasite has been demonstrated using genomic mapping of samples from this period, confirming the emergence of genes conferring a reduced risk of developing the malaria infection. References to the disease can be found in manuscripts from ancient Egypt, India and China, illustrating its wide geographical distribution.