number of virulence genes or genetic diversity between M. tuberculosis and M. africanum. No animal reservoir has been identified for Mycobacterium africanum despite having been found various wild animals. It has a similar degree of infectivity to the regular M. tuberculosis organism but is less likely to progress to clinical disease in an immunocompetent individual. However, M. africanum is more likely to progress from infection to causing disease in an HIV positive patient. In countries where M. africanum is endemic, it represents an important opportunistic infection of the later stages of HIV disease. Pathogenesis It is not fully understood how the genetic differences between M. africanum and M. tuberculosis give rise to the lower pathogenicity of the former. However, it is known that the Region of Difference 9 (RD9) is lacking in M. africanum but present in M. tuberculosis. M. africanum also has notable differences in lipid catabolism and metabolism. Additionally, virulence pathways such as the dosR/Rv0081 regulon or ESAT-6 regulation are disrupted in M. africanum. Treatment Because of the similar symptoms and different growth conditions between Mycobacterium tuberculosis and africanum, culture methods are unreliable for diagnosis. Molecular biology-based genotyping has improved identification. In particular, "spoligotyping" or "spacer oligonucleotide typing", is a rapid polymerase chain reaction-based method for genotyping strains in the MTBC. Recently, lateral flow rapid tests have been developed based on the mpt64 antigen found in all members of the MTBC. M. africanum has a lower rate of progression from latency to active disease than M. tuberculosis. M. africanum tuberculosis is treated with an identical regime to tuberculosis caused by M. tuberculosis. The overall rate of cure is similar, but as more M. africanum patients are likely to be HIV positive, they may have higher mortality from other HIV-related disease. Type strain ATCC 25420 = CIP 105147 References Bibliography External links Mycobacterium africanum in the NCBI Taxonomy Browser Type strain of Mycobacterium africanum at BacDive – the Bacterial Diversity Metadatabase Acid-fast bacilli Tuberculosis africanum Bacteria described in 1969