Research on Infectious Disease Epidemiology

Background

Epidemiology is the study of the distribution of human diseases and their determinants in contexts of time, place and person. Infectious disease is a unique condition as, different from other health conditions, there are at least two instead of one living organisms involved – the human host and the microorganism. The presence of intermediate hosts and/or vectors further complicates the picture. Naturally, the transmission dynamics of the infections and the environmental influences cannot be investigated by examining the host or the microorganism in isolation.

In studying infectious disease epidemiology, application of appropriate methodology is crucial. The complex inter-relationship between host and microorganisms, interplay of environment and genetics, and the non-random distribution of the human population, remind us that an integrative approach incorporating different methods can be a more effective strategy. Innovation and methodological exploration are also needed.

The Infectious Disease Epidemiology Group (IDEG) has adopted an interdisciplinary approach to studying infections ranging from human immunodeficiency virus (HIV), hepatitis C virus (HCV) tuberculosis (TB), influenza and other infections which emerge from time to time.

Objectives

The CEID ID Epidemiology Research Group aims to enhance our understanding of the epidemiology of infections in support of the development of effective public health interventions. Specifically the Group's objectives are, to:

• Describe the epidemiology of emerging infections posing threats to human populations;
• Innovate in methodological explorations of infections and their determinants;
• Enhance knowledge in infectious diseases through an integration of different epidemiologic approaches.

Our Scope

HIV/AIDS

We have set up observational HIV cohort databases in conjunction with HIV clinical services to describe and track the epidemiologic patterns of HIV infection in Hong Kong. On a community level, field-based studies are conducted to understand the epidemiologic pattern in hard-to-reach populations, including commercial sex workers (CSW), injection drug users (IDU) and men having sex with men (MSM).

Methodologically we investigate the molecular epidemiology of HIV infection in Hong Kong and neighbouring cities; explore clustering of infections and risk behaviours through the application of social network analysis methodology, GIS (geographic information system) in conjunction with molecular tools. Qualitative and multilevel approaches have also been adopted to investigate population vulnerability to HIV and related infections.

HCV

Hepatitis C virus (HCV) is a surrogate marker of high risk behaviours in injection drug users (IDU). We began our study of HCV epidemiology with seroprevalence studies in a cohort of IDU in the neighbourhood of methadone clinics in Hong Kong. This was expanded to involve molecular epidemiology studies, spatial exploration and multilevel studies on the vulnerability of IDU. Alternative risk factors to HCV infection in non-IDU is another theme of ongoing research.

TB and influenza

Respiratory tract infections are an important cause of mortality and morbidity in our society. Using GIS, the spatial contexts of TB is explored to determine factors associated with the infection or disease. Both spatial and temporo-spatial analyses are developed in investigating seasonal influenza and human pandemic influenza (H1N1). Syndromic surveillance using indicators like influenza like illnesses (ILI) and fever are piloted to supplement existing mechanisms on influenza surveillance. Influenza vaccine coverage in health care workers is assessed on a regular basis to evaluate risk of virus transmission in the community.

Sexually transmitted infections

Sexually transmitted infections (STI) are both a risk factor for HIV spread and a marker for sexual risk behaviours. Through supporting the running of a sexual health clinic for female sex workers, efforts are made to understand and examine the epidemiology of various bacterial (Chlamydia and gonorrhoea) and viral STI (HIV and HPV) in this sub-population.

Selected Publications

Coordinator

Professor SS Lee
Stanley Ho Centre for Emerging Infectious Diseases
The Jockey Club School of Public Health and Primary Care
Chinese University of Hong Kong
Prince of Wales Hospital
Shatin, Hong Kong

Tel:	(852) 2252 8812
Fax:	(852) 2635 4977
Email:	sslee@cuhk.edu.hk