Dr Doris Chibo

Position:

Senior Scientist, State Reference Laboratory for HIV Characterisation

Theme(s):

Viral Infectious Diseases, HIV

Discipline(s):

Public Health

Unit(s):

Victorian Infectious Diseases Reference Laboratory (VIDRL)

Lab Group(s):

Chibo Group

Doris completed her PhD by publication at RMIT University in 2008, her thesis describing several pathways by which viral evolution occurs. Previously, she was the molecular virologist in VIDRL’s WHO Regional Measles Reference Laboratory and was the first to document the absence of an indigenous measles virus strain circulating in Australia post introduction of the vaccine. She has also been involved in the formulation of molecular assays and phylogenetic protocols used in forensic examination of HIV cases where accusations of deliberate transmission of HIV have been made, the results of which can be used as evidence in court proceedings.

Mapping the molecular epidemiology of HIV-1 infection in Australia

The HIV Characterisation laboratory is involved in an Australia-wide project aimed at investigating the application of molecular epidemiological tools to assist the understanding of HIV genetic diversity and transmission patterns through the analyses of HIV cohorts in NSW, Victoria, Western Australia, South Australia and Queensland. Understanding the ongoing changes in the genetic diversity of the HIV epidemic has important implications for transmission dynamics, diagnostics, antiretroviral drug resistance and disease progression. This unique clinical and public health initiative aims to improve clinical outcomes and monitor HIV transmission patterns to inform HIV prevention and management in Australia.
Epidemiological trends in HIV in Victoria among persons not reporting male-to-male sex

In Victoria, the HIV epidemic is largely dominated by transmission through networks of men who have sex with men (MSM). Accordingly, surveillance and guidelines for testing and prevention are largely focused on this population. In collaboration with the Burnet Institute, Doris’ group aims to characterise epidemiological trends in non-MSM HIV notifications in Victoria in order to better understand the needs of diverse populations who may be at increased risk of HIV acquisition and transmission.
Analysis of transmitted HIV drug resistance to the newest class of antiretrovirals

Baseline genotyping of the virus infecting an HIV-positive individual is part of standard-of-care treatment. It reveals that transmitted drug resistance (TDR), typically to protease and reverse transcriptase inhibitors, continues to be important for the management of HIV infection. The increasing use of integrase inhibitors raises concern that TDR to this class of antiretroviral drugs may also occur. Analysis of genotyping data from this cohort will provide insight into whether there has been transmission of virus resistant to this new class of antiretrovirals to newly infected individuals and also provide recommendations for management and treatment of people infected with HIV-1.
Temporal changes in the prevalence of HIV drug resistance mutations

The advent of highly active antiretroviral therapy (HAART) in the late 1980s has seen significant reduction in the morbidity and mortality rates of people living with HIV in Australia. The development of antiretroviral resistance and cross-resistance to more than one drug in a given drug class has made treatment management challenging. Using an antiretroviral drug resistance mutation database established at VIDRL since 2001, Doris’ group seeks to investigate the changes in HIV drug resistance mutation frequencies and determine if these changes coincide with changes in doctors’ drug prescribing habits over time.
Molecular Epidemiology of HTLV-I in the Northern Territory

Human T-cell lymphotropic virus type 1 (HTLV-1) infects approximately 10-20 million people worldwide, with clusters of high endemicity in certain geographic areas or ethnic groups, including central Australia. Seven subtypes have been described including the Australo-Melanesian subtype C (HTLV-1c). With limited sequence information available, Doris’ group seeks to investigate the molecular epidemiology of this virus in Australia. Phylogenetic analyses of LTR and envelope sequences confirm the clustering of the Australian subtype with HTLV-1c. When compared to sequences collected from a patient in 1988, there is very limited genetic variation, indicating that the virus has remained stable over time.

Chibo Group

The HIV Characterisation laboratory performs testing to monitor HIV-infected individuals prior to and upon commencement of antiretroviral treatment. Additionally, genotype-assisted antiretroviral resistance testing is available, which identifies the presence of drug resistance mutations so that targeted treatment choices can be made.

Lab Team

Megan Gooey

Jodie D’Costa

Nicole Richards

Rizmina Sameer

Elaine Lee