Center for Health Protection

Kowloon, Hong Kong

Center for Health Protection

Kowloon, Hong Kong
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Arvand M.,Center for Health Protection | Raoult D.,French National Center for Scientific Research | Feil E.J.,University of Bath
PLoS ONE | Year: 2010

Bartonella quintana is a re-emerging pathogen and the causative agent of a variety of disease manifestations in humans including trench fever. Various typing methods have been developed for B. quintana, but these tend to be limited by poor resolution and, in the case of gel-based methods, a lack of portability. Multilocus sequence typing (MLST) has been used to study the molecular epidemiology of a large number of pathogens, including B. henselae, a close relative of B. quintana. We developed a MLST scheme for B. quintana based on the 7 MLST loci employed for B. henselae with two additional loci to cover underrepresented regions of the B. quintana chromosome. A total of 16 B. quintana isolates spanning over 60 years and three continents were characterized. Allelic variation was detected in five of the nine loci. Although only 8/4270 (0.002%) of the nucleotide sites examined were variable over all loci, these polymorphisms resolved the 16 isolates into seven sequence types (STs). We also demonstrate that MLST can be applied on uncultured isolates by direct PCR from cardiac valve tissue, and suggest this method presents a promising approach for epidemiological studies in this highly clonal organism. Phylogenetic and clustering analyses suggest that two of the seven STs form a distinct lineage within the population. © 2010 Arvand et al.

Leung C.C.,Center for Health Protection | Lange C.,Research Center Borstel | Zhang Y.,Johns Hopkins University
Respirology | Year: 2013

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), has developed various mechanisms to survive and cause disease in the human host. Incomplete understanding of the complex microbe-host interactions has hindered the identification of suitable biomarkers to expedite the development of diagnostic tools, drugs and vaccines. The field effectiveness of directly observed therapy-short course has been compromised by the intrinsic limitations of sputum microscopy and suboptimal adherence to the long duration of treatment amid the HIV-TB syndemic and various socioeconomic constraints. While molecular tools are transforming the diagnostic processes, especially for multi-drug-resistant (MDR)-TB, drug development and service provision for MDR-TB seriously lag behind. Inappropriate management of detected MDR-TB cases may amplify drug resistance, jeopardizing future control. Targeted screening and treatment of latent infection with M. tuberculosis with the currently available immunodiagnostic tools and treatment regimens aim more for personal protection than major epidemiological impact or elimination. The interferon-γ release assays (IGRA) are not affected by cross-reaction to the bacillus Calmette-Guérin (BCG) vaccine and are increasingly used for such screening before initiation of biologics for treatment of rheumatoid arthritis and other autoimmune disorders. BCG offers only partial and unreliable protection against pulmonary TB in adults, the crucial transmission link for this airborne infection. Systems biology and vaccinomics may speed up vaccine research. The successful development of a fully effective TB vaccine that targets both growing bacteria and non-growing persisters may reflect a major breakthrough, as natural infection does not induce sufficient immunity to prevent reinfection. © 2013 Asian Pacific Society of Respirology.

Leung C.C.,Center for Health Protection | Yu I.T.S.,Chinese University of Hong Kong | Chen W.,Huazhong University of Science and Technology
The Lancet | Year: 2012

Silicosis is a fibrotic lung disease caused by inhalation of free crystalline silicon dioxide or silica. Occupational exposure to respirable crystalline silica dust particles occurs in many industries. Phagocytosis of crystalline silica in the lung causes lysosomal damage, activating the NALP3 inflammasome and triggering the inflammatory cascade with subsequent fibrosis. Impairment of lung function increases with disease progression, even after the patient is no longer exposed. Diagnosis of silicosis needs carefully documented records of occupational exposure and radiological features, with exclusion of other competing diagnoses. Mycobacterial diseases, airway obstruction, and lung cancer are associated with silica dust exposure. As yet, no curative treatment exists, but comprehensive management strategies help to improve quality of life and slow deterioration. Further efforts are needed for recognition and control of silica hazards, especially in developing countries.

Ho M.,Center for Health Protection | Seto W.,World Health Organization | Wong L.,Center for Health Protection | Wong T.,Center for Health Protection
Infection Control and Hospital Epidemiology | Year: 2012

Objective. To determine the effectiveness of World Health Organization (WHO) multimodal strategy in promoting hand hygiene (HH) among healthcare workers (HCWs) in long-term care facilities (LTCFs). Design. Cluster-randomized controlled trial. Setting. Eighteen homes for the elderly in Hong Kong were randomly allocated to 2 intervention arms and a control arm. Direct observation of HH practice was conducted by trained nurses. Either hand rubbing with alcohol-based hand rub (ABHR) or hand washing with liquid soap and water was counted as a compliant action. Disease notification data during 2007-2010 were used to calculate incidence rate ratio (IRR). participants. Managers and HCWs of the participating homes. Interventions. The WHO multimodal strategy was employed. All intervention homes were supplied with ABHR (WHO formulation I), ABHR racks, pull reels, HH posters and reminders, a health talk, video clips, training materials, and performance feedback. The only difference was that intervention arms 1 and 2 were provided with slightly powdered and powderless gloves, respectively. Results. A total of 11,669 HH opportunities were observed. HH compliance increased from 27.0% to 60.6% and from 22.2% to 48.6% in intervention arms 1 and 2, respectively. Both intervention arms showed increased HH compliance after intervention compared to controls, at 21.6% compliance (both P < .001). Provision of slightly powdered versus powderless gloves did not have any significant impact on ABHR usage. Respiratory outbreaks (IRR, 0.12; 95% confidence interval [CI], 0.01-0.93; P = .04) and methicillin-resistant Staphylococcus aureus infections requiring hospital admission (IRR, 0.61; 95% CI, 0.38-0.97; P = .04) were reduced after intervention. Conclusions. A promotion program applying the WHO multimodal strategy was effective in improving HH among HCWs in LTCFs. © 2012 by The Society for Healthcare Epidemiology of America. All rights reserved.

Chan D.Y.W.,Center for Health Protection
Journal of Paediatrics and Child Health | Year: 2014

Aim Acute flaccid paralysis (AFP) surveillance system was set up in Hong Kong in 1997 for World Health Organization's (WHO) certification of poliomyelitis eradication. This paper describes and reviews the demographic, clinical and virological characteristics of AFP cases reported to the system in its first 15 years. Methods All patients aged under 15 years presented with acute onset of paralysis of any limbs reported to the Department of Health from January 1997 to December 2011 were reviewed. Data on demographic characteristics, vaccination history, clinical presentation and virological investigation on stool specimens collected during investigation were analysed with descriptive statistics. Results Of the 247 cases reported, about 45% were aged under five. All cases were classified as non-polio AFP according to WHO classification. About 60% were identified with neurological disorders, with Guillain-Barré syndrome (25.9%) and myelitis (13.4%) being the most common. Viruses were detected in 14.0% of the AFP cases, with non-polio enteroviruses (NPEV) (60.0%) and adenoviruses (31.4%) accounted for most of the positive detections. Most performance indicators set by the WHO were fulfilled. Conclusions The AFP surveillance facilitated the clinical, virological and epidemiological examination of paediatric AFP cases. From 1997 to 2011, Guillain-Barré syndrome and myelitis were the most common among paediatric AFP cases in Hong Kong. NPEV and adenoviruses accounted for most of the positive viral detections. No wild poliovirus was detected, and all cases were classified as non-polio AFP. © 2014 The Author. Journal of Paediatrics and Child Health © 2014 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Mak G.C.,Center for Health Protection
Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin | Year: 2011

Phylogenetic analysis of the haemagglutinin (HA) gene shows that the influenza A(H1N1)2009 viruses collected in Hong Kong clustered in two main branches characterised by the E391E and E391K amino acids. The main branch E391K evolved in two sub-branches with N142D and S202T mutations that first appeared in March and July 2010, respectively, with the latter becoming the predominant strain. These genetic variants that emerged display similar antigenic characteristics.Concurrent with genetic surveillance, laboratories should continue monitoring the circulating viruses antigenically.

Mak G.C.,Center for Health Protection | Wong A.H.,Center for Health Protection | Ho W.Y.Y.,Center for Health Protection | Lim W.,Center for Health Protection
Influenza and other Respiratory Viruses | Year: 2012

Surveillance of respiratory viruses has been conducted for many years at the public health laboratory in Hong Kong. With the occurrence of pandemic influenza A (H1N1) 2009, we observed a change in the seasonality of influenza activity with a seemingly corresponding change in the activity of respiratory syncytial virus, parainfluenza virus, and adenovirus during 2009-2011. This phenomenon could most likely be explained by virus interference. © 2012 Blackwell Publishing Ltd.

Adamson S.,Center for Health Protection
New South Wales public health bulletin | Year: 2011

Zoonoses of public health significance may occur in wildlife, livestock or companion animals, and may be detected by the human or animal health sectors. Of particular public health interest are foodborne, arboviral and emerging zoonoses (known/unknown, endemic/exotic). A coordinated One Health approach to the management of zoonoses in NSW uses measures including: mutually agreed intersectoral procedures for detection and response; surveillance and notification systems for defined endemic and exotic diseases; joint meetings and exercises to ensure currency of response plans; and intersectoral communication during a response. This One Health approach is effective and ensures the interests of both the human health and animal health sectors are addressed.

Leung Y.H.,Center for Health Protection | Li M.P.,Center for Health Protection | Chuang S.K.,Center for Health Protection
Epidemiology and Infection | Year: 2011

In mid-June 2009, an outbreak of pandemic (H1N1) 2009 (pH1N1) infection occurred in a secondary school in Hong Kong. We carried out an epidemiological investigation to delineate the characteristics of the outbreak, gauge the extent of secondary household transmission, and assess the protective role of oseltamivir in household contacts. We interviewed pH1N1-confirmed cases using a standardized questionnaire. Sixty-five of 511 students in the school were affected. Of the 205 household contacts identified, 12 were confirmed as cases. All cases recovered. The estimated secondary household attack rate was 59% (95% CI 27-91). Household contacts aged <18 years were about 15 times more likely to be infected than older contacts. Household contacts who had received oseltamivir prophylaxis were less likely to acquire a secondary infection than those who had not (odds ratio=0). The estimated mean household serial interval of pH1N1 virus was 28 days (95% CI 21-34 days). © 2010 Cambridge University Press.

Lo J.Y.C.,Center for Health Protection | Ho K.M.,Center for Health Protection | Lo A.C.T.,Center for Health Protection
Journal of Antimicrobial Chemotherapy | Year: 2012

Objectives: To undertake laboratory and clinical surveillance of gonococcal antimicrobial susceptibility to various therapeutic agents in Hong Kong, so as to monitor for emerging resistance and to inform on appropriate choice of empirical therapy. Methods: Trends in susceptibility of gonococci to ceftriaxone, spectinomycin, ceftibuten and azithromycin were monitored over time. Isolates with reduced susceptibility to oral extended-spectrum cephalosporins were further characterized by detection of the mosaic penA gene and typing by Neisseria gonorrhoeae multi-antigen sequence typing (NG-MAST). Correlation with clinical and epidemiological findings was undertaken on isolates positive for the mosaic penA gene. Results: Trends in susceptibility of gonococci to ceftriaxone, spectinomycin and ceftibuten remained stable between 2005 and 2010. In 2010, 30.3% of tested strains were not susceptible to azithromycin. The percentage of gonococcal strains harbouring the mosaic penA gene increased from 1.0% during April to December 2010 to 8.2% during January to September 2011 (P < 0.0001). Review of available clinical records showed that, out of 35 patients infected by strains positive for the mosaic penA gene, 30 had laboratory-documented treatment failure. Conclusions: This study showed that ceftriaxone and spectinomycin remained effective against gonorrhoea in Hong Kong. There was an alarming increase in strains with reduced susceptibility to oral extended-spectrum cephalosporins associated with clinical treatment failure. One-third of gonococcal isolates were non-susceptible to azithromycin. The need to switch to agents other than oral extended-spectrum cephalosporins for empirical treatment is imminent. Continued surveillance with strain characterization is essential to monitor the effectiveness of currently recommended therapy. © The Author 2012. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

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