Hong Kong government conducts public health exercise “Prehnite” to test preparedness for plague outbreak


27th November 2023 – (Hong Kong) The Centre for Health Protection (CHP) of the Department of Health (DH), in collaboration with various government departments, carried out a comprehensive public health exercise on 27th November, code-named “Prehnite,” to assess their readiness in handling an imported case of plague. The exercise aimed to strengthen the execution and coordination capabilities of the DH and relevant government agencies in response to plague cases, as well as to raise awareness among stakeholders regarding the management of public health emergencies.

The exercise consisted of two parts. The first part, conducted on November 20, involved a table-top exercise where nine relevant departments and the Hospital Authority (HA) discussed and coordinated response measures for a simulated scenario involving the transmission of plague in a residential building.

The second part of the exercise took place on November 27 and involved a ground movement simulation. In this scenario, the CHP was informed by the HA about a suspected case of plague. The CHP promptly initiated epidemiological investigations, which revealed that the patient had visited an area experiencing a plague outbreak during the incubation period. Upon returning to Hong Kong, the patient resided in a residential building with family members. After exhibiting symptoms, the patient had interactions with neighbours and visited different areas within the building. The CHP coordinated with relevant government departments to conduct a site visit to the building, trace contacts of the index case, and implement evacuation and quarantine operations. Additionally, they conducted surveys in and around the building to identify and control rodent and flea infestations. The ground movement exercise involved approximately 70 participants from various government departments, with 30 experts from Mainland China and Macao health authorities observing the exercise.

Plague is a communicable disease caused by the bacteria Yersinia pestis, which affects both animals and humans. It can manifest in three main forms: bubonic, pneumonic, and septicaemic. While most human cases have occurred in Africa since the 1990s, the disease can be transmitted from infected animals, primarily rodents, to humans through flea bites. Contact with infected animal fluids or tissue through cuts or breaks in the skin, consumption of infected animal tissue, and inhalation of infected respiratory droplets are also possible modes of transmission. Plague is a severe illness, with a case-fatality ratio ranging from 30 to 60 per cent for the bubonic type and typically fatal for the pneumonic and septicaemic types if left untreated. According to the World Health Organization, 2,886 cases, including 504 deaths, were reported in 11 countries worldwide from 2013 to 2018, with over 90 per cent of cases recorded in sub-Saharan Africa.

The DH spokesperson highlighted Hong Kong’s historical experience with plague, which occurred in May 1894, resulting in at least 5,000 cases. From 1894 to 1929, over 20,000 cases were reported in Hong Kong, with a mortality rate of approximately 90 per cent. Although Hong Kong has not recorded any plague cases since 1929, the presence of rats and rat fleas, the high volume of international traffic, and the disease’s prevalence in other regions necessitate vigilance and preparedness.

The DH spokesperson emphasised the value of such exercises in testing the response capabilities of relevant government departments and the HA in managing plague outbreaks. The DH has previously conducted 28 similar exercises addressing scenarios like novel influenza, Middle East Respiratory Syndrome, and Ebola virus disease. These exercises aim to enhance the community’s and healthcare personnel’s awareness of potential epidemics, keeping them alert and well-prepared.