1. International AIDS Society
Evidence of Local HIV Transmission in the African Community of King County, Washington
Roxanne Kerani, Joshua Herbeck, Susan Buskin, Julia Dombrowski, Amy Bennett, Elizabeth Barash, Lindley Barbee, Matthew Golden
As we have heard from previous presenters, African-born people represent a disproportionate share of HIV cases in several countries in Europe and North America, particularly among people who are believed to have acquired HIV heterosexually. As our last presenter noted, several European have estimated that around 1/3 of heterosexual cases acquired HIV in Europe. For this study, we were interested in estimating the proportion of African-born HIV cases in our county who may have acquired HIV in the U.S..
International AIDS Society
July 22, 2015

2. Methods Study setting: King County, WA
HIV surveillance and partner services data
African-born PLWHA reported from
Phylogenetic analysis with HIV-1 viral sequences collected Jan, 2008-Feb, 2014
Partial HIV pol sequences
We added pol sequences from Kenya and Ethiopia, as well as additional pol sequences of African HIV-1 subtypes
Aligned sequence dataset using MUSCLE with GENEIOUS v. 8
Reconstructed maximum likelihood phylogenies with General Time Reversible model of nucleotide substitution
Identified clusters as > 2 sequences with shared ancestral node
Assessed the robustness of the clusters with node support values and maximum pairwise genetic distance (3.0%)
Study period:
Location: King County, WA – Seattle area
97 of 1, 100 reported cases were African-born (9%)
This presentation focuses primarily on 41 cases who were interviewed and did not report or were not found to have been previously being diagnosed outside of King County.

3. HIV Testing and Sexual Partners
Among African-born PLWHA*:
34% had a previous negative test
28% had a negative test before arrival in U.S.
11 (26%) had a previous negative test after arrival in the U.S.
41 patients 45 partners
6 (13%) previously positive
9 (23%) newly tested
Among patients not previous diagnosed elsewhere
Of 6 previously positive partners, 3 were interviewed and all Af-born
Of 4 newly positive partners, all interviewed, 3 African-born
4 (44%) newly positive
* N=41 not previously diagnosed elsewhere

4. Phylogenetic Analysis HIV-1 pol Sequences from 2008 – Feb, 2014*
1,399 local sequences, 112 from African-born PLWHA
34 African-born individuals (20 pairs) shared most recent ancestral node
The remaining 78 sequences from African-born PLWHA were linked most closely to sequences from Africa
7/11 PLWHA cases with a previous negative test in the U.S. had a viral sequence
9 putative transmission clusters
(<3.0% pairwise distance)
N=1,399 total sequences
Based on genetic distance and/or node support thresholds, 9 pairs were identified as putative transmission clusters
2/7 belonged to a local transmission cluster
6/9 transmission clusters included only African-born individuals
2/7 were infected with subtype B (distinct from above)