Background HIV diagnosis rates have steadily increased in Australia over the past 13 years

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An epidemic in transition: impacts of migration and local networks on HIV sequence diversity and infection transmission in Australia 2005-2012Alison 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 mutationsCollaboration established involving HIV-1 genotyping services in five states (NSW, VIC, SA, QLD & WA)

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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).

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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 non-B-subtype among males across all states. Overall rate 19.8% (763/3862).

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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.

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Results (2)

Conclusions

• 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.

• 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 male-dominated 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 viral diversity.