Clostridium difficile is an anaerobic, gram-positive bacterium, capable of sporulation when environmental conditions no longer support its growth. The sporulation capacity enables the organism to persist in the environment for extended periods of time. Clostridium difficile is the main pathogen accountable for antibiotic-associated colitis and for 15% to 25% of cases of nosocomial antibiotic-associated diarrhoea. Major risk factors such as increased severity of underlying illness, increased age, prior antimicrobial use and gastric acid suppressors have been identified for Clostridium difficile.

Background：In November 2012, an outbreak of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft tissue infections affecting students at a boarding school in Hong Kong Special Administrative Region (China) was detected.Methods：A case was defined as any student or staff notified with MRSA infection from 25 October 2012 to 5 July 2013 with the clinical isolate being of staphylococcal cassette chromosome mec type IV or V and positive for Panton-Valentine leukocidin gene. We conducted field investigations, advised on control measures and enhanced surveillance for skin and soft tissue infections at the school. Decolonization therapies were offered to all cases and contacts, and carrier screening was conducted.Results：There were five cases; two (40%) were hospitalized and three (60%) required surgical treatments. Initial screening comprised 240 students and 81 staff members. Overall, four cases (80%) plus eight other students (3.3%) were carriers, with eight of 12 (66.7%) from the same dormitory. All staff members screened negative. After intensified control measures, the number of students screened positive for CA-MRSA decreased from nine to one with no more cases identified in the school.Conclusion：Identification of carriers, decolonization therapy, monitoring of cases and contacts and strengthening of environmental and personal hygiene were control measures that helped contain this CA-MRSA outbreak in a boarding school in Hong Kong Special Administrative Region (China).

The International Health Regulations (IHR) (2005) require World Health Organization Member States to notify events fulfilling two of four criteria: (1) serious public health impact; (2) unusual or unexpected event; (3) significant risk of international spread; or (4) significant risk of international travel or trade restrictions. In-flight transmission of infections like severe acute respiratory syndrome is well documented. With the enormous amount of air travel today, the risk of increasing in-flight transmission and subsequent international spread of infections are increasing. Prompt notification and information sharing under the IHR mechanism is critical for effective contact tracing and prompt control measures. We report on a case of in-flight exposure to an infection with significant public health risks that was successfully resolved using IHR (2005) guidelines.

Introduction: Hong Kong SAR (China) achieved measles elimination status in 2016, and the incidence of measles infection had been low over the past few years. However, the Centre for Health Protection (CHP) at the Department of Health was notified on 22 March 2019 of an outbreak of three cases of measles infection among workers at the Hong Kong International Airport (HKIA). Methods: We reviewed notifications of measles received by CHP from 1 January to 17 May 2019. We defined a confirmed case of measles as having laboratory evidence of measles infection. All confirmed cases among airport workers or those with epidemiological information suggesting they had been infected by contact with airport workers were included in the review. We described the epidemiological features and reviewed the control measures against the outbreak. Results: We identified 33 cases, 29 of which were among airport workers. They comprised 22 men and 11 women, aged 20–49 years (median 25 years). The majority of people with confirmed measles presented with fever and rash. All required hospitalization. None developed complications. Control measures, including enhanced environmental hygiene and improved ventilation at HKIA and vaccinations for the airport community, were implemented. Discussion Early recognition of the outbreak and prompt control measures, especially targeted vaccination of the exposed population, effectively controlled the outbreak in just two weeks.

We reported a local family cluster of 6 confirmed COVID-19 cases among 29 attendees of a Chinese New Year family dinner gathering in a restaurant, with 1 additional case from secondary transmission. This report illustrates that the public should maintain physical distancing during the COVID-19 pandemic.

Objective: An outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan, China, in December 2019, with subsequent spread around the world. Hong Kong Special Administrative Region SAR (China) recorded its first confirmed cases on 23 January 2020. In this report, we describe a family cluster of 12 confirmed cases, with two additional confirmed cases from secondary transmission. Methods: We reported the epidemiological, clinical and laboratory findings of the family cluster, as well as the public health measures instituted. Results: All 12 confirmed COVID-19 cases were among the 19 attendees of a three-hour Chinese New Year family dinner consisting of hotpot and barbecue dishes. Environmental sampling of the gathering venue was negative. Two additional confirmed cases, who were co-workers of two confirmed cases, were later identified, indicating secondary transmission. Contact tracing, quarantine and environmental disinfection were instituted to contain further spread. Discussion: Our findings were highly suggestive of a superspreading event during the family gathering. The source was likely one of the cases during the pre-symptomatic phase. The event attested to the high infectivity of SARS-CoV-2 through human-to-human transmission from social activities and argued for the necessity of social distancing in curtailing the disease spread.