History More prevalent in 19 th Century due to nature of spread: –Overcrowding –Poor housing conditions –Hygiene Streptomycin introduced in UK (& developed world) c. 1940s. Incidence dropped sharply. BCG vaccinations in 1950s decreased prevalence further.
History (cont.) Once thought to be eradicated but recent resurgence due to: –M. tuberculosis antibiotic resistance –AIDS –Poor housing/homelessness in inner cities –Complacent partial treatment programmes (esp. USA) In 1995 more people died from TB worldwide than any other disease. 1/3 of world’s population is infected with M. tuberculosis.
Antibiotic Resistance If just one drug is used, it acts as a selective agent and resistant strains survive. Exacerbated by failure of people to complete course of antibiotics. M. tuberculosis is slow growing so takes months to cure. Better to use 3 or 4 drugs – reduces likelihood of resistance. In 1995 an HIV unit reported an MDR-TB (multiple drug resistant M. tuberculosis ) resistant to FIVE of the major TB drugs.
= Hot spots (at least 4% are MDR-TB) = Outbreaks The Worldwide Problem