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An epidemic in transition: impacts of migration
and local networks on HIV sequence diversity and
infection transmission in Australia 2005-2012
Alison Castley1, Shailendra Sawleshwarkar2, Rick Varma2, Belinda Herring2, Kiran Thapa2, Doris Chibo3, Nam
Nguyen4, Karen Hawke5,6, Rodney Ratcliff5,6, Dominic E Dwyer2, David Nolan1.
The Australian Molecular Epidemiology Network-HIV (AMEN-HIV)
1Department of Clinical Immunology, Royal Perth Hospital, Perth WA 6000, 2Western Sydney Sexual Health Centre and Centre for Infectious Diseases and Microbiology
Laboratory Services, ICPMR-Pathology West, Westmead Hospital and University of Sydney, Westmead NSW 2145, 3 HIV Characterisation Laboratory, Victorian Infectious
Diseases Reference Laboratory, Melbourne, Victoria, 3000, 4 Division of Immunology, HQS Pathology Queensland Central Laboratory, RBWH Herston, QLD 4029, 5 Clinic
275, Royal Adelaide Hospital, Adelaide, Australia, 6 Department of Microbiology and Infectious Diseases, SA Pathology, Adelaide South Australia.
Background
• HIV diagnosis rates have steadily increased in
Australia over the past 13 years
• 26% increase in population rate since 2003
• 1,253 new cases in 2012 (10% compared to 2011)
• set against downward global trend in new HIV
diagnoses.
• HIV genotype determination routinely performed
in an Australian setting pre-treatment
• provides valuable information on the geographic
origin of the infecting HIV-1 subtype
• can also identify transmission networks through
phylogenetic analysis
• identifies transmitted drug resistance mutations
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Collaboration established involving HIV-1 genotyping
services in five states (NSW, VIC, SA, QLD & WA)
Methods
• 4432 HIV positive patients identified during 2005-2012.
• Age and gender and Australian state noted, no other identifiable data.
• HIV-1 subtype determined using the Stanford Drug Resistance Database.
• Phylogenetic analysis performed utilising BioEdit Sequence Alignment Editor tool and Molecular
Evolutionary Genetics Analysis Version 5 (MEGA V5) to infer phylogenetic clustering patterns based on
sequence similarity.
• Methods previously applied to studies of global HIV-1 transmission networks1
1Wertheim
JO, et al. The Global Transmission Network of HIV-1. J Infect Dis. 2014;209:304–13
Results (1)
• Non-B-subtype HIV-1 = 1179 cases (26.6%)
• increasing overall trend from 2005-2012
• High proportion of non-B-subtype HIV-1 in West Sydney
(average 52%) and WA (45%) throughout
• Increasing trends in other states, from baseline rates of
10-15% to peak levels of 46% (SA), 36% (VIC) and 23%
(Qld).
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Methods
• 4432 HIV positive patients identified during 2005-2012.
• Age and gender and Australian state noted, no other identifiable data.
• HIV-1 subtype determined using the Stanford Drug Resistance Database.
• Phylogenetic analysis performed utilising BioEdit Sequence Alignment Editor tool and Molecular
Evolutionary Genetics Analysis Version 5 (MEGA V5) to infer phylogenetic clustering patterns based on
sequence similarity.
• Methods previously applied to studies of global HIV-1 transmission networks1
1Wertheim
JO, et al. The Global Transmission Network of HIV-1. J Infect Dis. 2014;209:304–13
Results (1)
• Non-B-subtype HIV-1 = 1179 cases (26.6%)
• increasing overall trend from 2005-2012
• High proportion of non-B-subtype HIV-1 in West Sydney
(average 52%) and WA (45%) throughout
• Increasing trends in other states, from baseline rates of
10-15% to peak levels of 46% (SA), 36% (VIC) and 23%
(Qld).
• Non-B-subtype in 73% of
females (416/570) across all
states with no apparent time
trend.
• Steady increasing trend in nonB-subtype among males across
all states. Overall rate 19.8%
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(763/3862).
Results (2)
• Phylogenetic analyses (WA)
demonstrate increasing HIV-1
diversity over time.
• Non-B-subtype HIV-1 transmission
clusters are generally pairs
associated with male/female
partnerships, with larger clusters
within male networks.
• Subtype-B HIV-1 predominantly
male, characterised by larger cluster
sizes with evidence of local
transmission networks up to 27
individuals.
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Results (2)
• Phylogenetic analyses (WA)
demonstrate increasing HIV-1
diversity over time.
• Non-B-subtype HIV-1 transmission
clusters are generally pairs
associated with male/female
partnerships, with larger clusters
within male networks.
• Subtype-B HIV-1 predominantly
male, characterised by larger cluster
sizes with evidence of local
transmission networks up to 27
individuals.
Conclusions
• First nationwide survey of HIV molecular epidemiology in Australia reveals increasing subtype
diversity with the emergence of non-B-subtypes among females and males
• Consistent with changing patterns of migration, overseas travel and domestic factors over time
and between states.
• Domestic transmission clusters predominantly involve HIV-1 B-subtype strains within maledominated networks, with emerging evidence of onward transmission of non-B subtype HIV-1
within Australia.
• This study highlights the complex interplay between travel, migration and domestic factors that
contribute towards new HIV-1 infections, changing global epidemiological profiles, and growing
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viral diversity.