Genetic evidence of multiple transmissions of HIV type 1 subtype F within Romania from adult blood donors to children

We studied the phylogeny of HIV-1 subtype F viruses from children and adult s in Romania in order to (1) clarify whether the Romanian subtype F epidemi c was caused by one or several virus introductions and (2) gain insight int o the route of spread of the HIV-1 subtype F virus among children and adult s in Romania, env (V3), gag (p17/half p24), and pol (prot/half RT) sequence s were obtained from three districts in Romania: Tirgu Mures (n = 9, childr en), Craiova (n = 15, children), and Bucharest (n = 13, adults). Of 37 HIV V3 sequences from Romania, 35 belonged to the genetic subtype F in the neig hbor-joining tree, whereas 2 sequences from adults clustered with subtypes A and C, Within the subtype F cluster, no bootstrap-supported subclusters w ere observed according to geographic area in Romania, Two of the adult V3 s equences that clustered with the children mere obtained from individuals wh o tested HIV seropositive in 1989 and 1990, showing that the subtype F viru s was present among adults when the HIV epidemic began among children in Ro mania, The HIV-1 subtype F viruses obtained from children showed a mean pai rwise V3 nucleotide distance of 7.9% and maximum distances of between 18 an d 19%; both are higher than previously described, The mean V3 distances (ov erall, synonymous, and nonsynonymous) were significantly higher for adults than for children. One V3 sequence from the Democratic Republic of Congo cl ustered within the Romanian sequences, suggesting that the subtype F virus in Romania may originate from this area. Our data also suggest that HIV-1 s ubtype F was present among Romanian adults before it appeared in 1989 among institutionalized children. The juvenile population was most likely infect ed with the HIV-1 subtype F virus on more than one occasion, presumably thr ough HIV-contaminated blood (products) obtained from adults.