Group M is the most prevalent and is subdivided into eight subtypes (or clades), based on the whole genome, which are geographically distinct. The most prevalent are subtypes B (found mainly in North America and Europe), A and D (found mainly in Africa), and C (found mainly in Africa and Asia); these subtypes form branches in the phylogenetic tree representing the lineage of the M group of HIV-1. Co-infection with distinct subtypes gives rise to circulating recombinant forms (CRFs). In 2000, the last year in which an analysis of global subtype prevalence was made, 47.2% of infections worldwide were of subtype C, 26.7% were of subtype A/CRF02_AG, 12.3% were of subtype B, 5.3% were of subtype D, 3.2% were of CRF_AE, and the remaining 5.3% were composed of other subtypes and CRFs. Most HIV-1 research is focused on subtype B; few laboratories focus on the other subtypes. The existence of a fourth group, "P", has been hypothesised based on a virus isolated in 2009. The strain is apparently derived from gorilla SIV (SIVgor), first isolated from western lowland gorillas in 2006.HIV-2s closest relative is SIVsm, a strain of SIV found in sooty mangabees. Since HIV-1 is derived from SIVcpz, and HIV-2 from SIVsm, the genetic sequence of HIV-2 is only partially homologous to HIV-1 and more closely resembles that of SIVsm. Diagnosis
Many HIV-positive people are unaware that they are infected with the virus.
Blantyre Coma Scale
The Blantyre Coma Scale is a modification of the Pediatric Glasgow Coma Scale, designed to assess malarial coma in children. It was designed by doctors Terrie Taylor and Malcolm Molyneux in 1987, and named for the Malawian city of Blantyre, site of the Blantyre Malaria Project. Rancho Los Amigos Scale
The Rancho Los Amigos Scale is used to assess individuals after a closed head injury based on cognitive and behavioural presentations as they emerge from coma. It is named after the Rancho Los Amigos National Rehabilitation Center, located in Downey, California, United States. FOUR score
See also
Level of consciousness


== References ==