The AIDS virus is spreading like an epidemic in some Middle East and North African countries because of homosexual encounters between men, a study warned on Wednesday. \"This systematic review and data synthesis indicate that HIV epidemics appear to be emerging among MSM (men who have sex with men) in at least a few MENA countries,\" said a study published in PLoS Medicine. The study, titled \"Are HIV Epidemics among Men Who Have Sex with Men Emerging in the Middle East and North Africa?\", warned that the levels \"could already be in a concentrated state among several MSM groups.\" It showed that the rates of HIV infection among MSM in some countries have exceeded the five percent threshold which defines concentrated epidemics, namely in Egypt, Sudan and Tunisia. The study put the rates of HIV infection among MSM in Egypt\'s main cities of Cairo and Alexandria at 5.7 percent and 5.9 percent respectively, while the rate among receptive MSM in Sudan\'s capital reached 9.3 percent. Tunisia\'s total rate was put at 4.9 percent, ranging between 0.8 and 6.3 percent in three regions. \"There is an urgent need to expand HIV surveillance and access to HIV testing, prevention, and treatment services in a rapidly narrowing window of opportunity to prevent the worst of HIV transmission among MSM in the Middle East and North Africa,\" the study said. \"Prevention of male-to-male HIV transmission must be set as a top priority for HIV/AIDS strategies in MENA,\" it added. PLoS, or the Public Library of Science, is an open-access, online medical journal.