The Food and Environmental Hygiene Department (FEHD) today (May 21) released the fourth batch of gravidtrap indexes and density indexes for Aedes albopictus in May, covering 12 survey areas, as follows:
 

District	Survey Area	May 2026
		First Phase Gravidtrap Index	First Phase Density Index
Eastern	Shau Kei Wan and Sai Wan Ho	9.1%	1.4
Islands	Tung Chung	2.0%	1.0
Kowloon City	Hung Hom and To Kwa Wan	6.7%	1.5
Tai Po	Tai Po East	2.2%	2.0
	Tai Po West	15.5%	1.0
Tuen Mun	Tuen Mun South	9.1%	1.4

 

District	Survey Area	May 2026
		Area Gravidtrap Index	Area Density Index
Central and Western	Kennedy Town and Shek Tong Tsui	16.8%	1.3
Eastern	Chai Wan	15.4%	1.0
	North Point and Quarry Bay	18.9%	1.4
Southern	Aberdeen and Ap Lei Chau	20.8%	1.7
Sha Tin	Sha Tin Town Centre and Fo Tan	18.3%	1.4
Tsuen Wan	Tsuen Wan Town	6.9%	2.3

     The fourth batch of gravidtrap indexes for Aedes albopictus in May includes First Phase Gravidtrap Indexes covering six survey areas and Area Gravidtrap Indexes covering six survey areas. Among which, six survey areas recorded gravidtrap indexes above 10 per cent, while Aberdeen and Ap Lei Chau in Southern District recorded a gravidtrap index above 20 per cent. Meanwhile, the gravidtrap indexes of six survey areas, namely Kennedy Town and Shek Tong Tsui in Central and Western District; North Point and Quarry Bay in Eastern District; Shau Kei Wan and Sai Wan Ho in Eastern District; Aberdeen and Ap Lei Chau in Southern District; Tai Po East in Tai Po District; and Tuen Mun South in Tuen Mun District, have recorded a decrease as compared to the indexes recorded in the last survey period, reflecting the progress of relevant mosquito control work.

     With reference to the data from the past few years, the gravidtrap indexes start to rise from April or May every year. The actual timing and extent of the rise are affected by factors like weather conditions and rainfall. The average temperature and rainfall recorded in April this year were higher than those in the same period last year, creating favourable conditions for mosquito growth and breeding. As a result, the rise in gravidtrap indexes occurred earlier this year. With the increase in rainfall in May, the gravidtrap indexes are expected to rise further.

     For survey areas which recorded indexes exceeding 10 per cent, in accordance with the mechanism implemented by the FEHD in response to the chikungunya fever (CF) situation (i.e. strengthening mosquito control work in areas with a gravidtrap index between 10 per cent and 20 per cent, instead of 20 per cent or above under the original mechanism), the FEHD is collaborating with relevant departments and stakeholders to identify locations with high mosquito infestations and carry out intensive and targeted mosquito control measures. The FEHD has initiated two prosecutions against the relevant construction site contractors following the discovery of mosquito breeding at construction sites in Tai Po District and Southern District. Moreover, following the discovery of stagnant water or stagnant water containers in a park, a construction site, a private housing estate, a clinic and a private premises in Tai Po District, Central and Western District, as well as Southern District, the FEHD has issued five statutory notices to the responsible persons-in-charge, requiring the clearance of such items within a specified timeframe. The FEHD, the relevant departments and stakeholders are following up on the mosquito control work, and will also organise exhibitions, distribute leaflets and posters, and notify residential estates that have subscribed to the gravidtrap Rapid Alert System, advising property management agents and residents to stay vigilant and work together in taking mosquito prevention and elimination measures. In addition, the FEHD will strengthen the monitoring of the gravidtrap index in the areas to review the effectiveness of the mosquito control work.

     Public participation is crucial to the effective control of mosquito problems. The FEHD appeals to members of the public to continue to work together in strengthening personal mosquito control measures, including:

• tidy up their premises and check for any accumulation of water inside the premises;
• remove all unnecessary water collections and eliminate the sources;
• check household items (those placed in outdoor and open areas in particular), such as refuse containers, vases, air conditioner drip trays, and laundry racks to prevent stagnant water;
• change water in flower vases and scrub their inner surfaces thoroughly, and remove water in saucers under potted plants at least once a week;
• properly cover all containers that hold water to prevent mosquitoes from accessing the water;
• properly dispose of articles that can contain water, such as disposable meal boxes and empty cans; and
• scrub drains and surface sewers with alkaline detergent at least once a week to remove any mosquito eggs.

     Starting in August 2025, following the completion of the surveillance of individual survey areas, and once the latest gravidtrap index and the density index are available, the FEHD has been disseminating relevant information through press releases, its website and social media. It aims to allow members of the public to quickly grasp the mosquito infestation situation and strengthen mosquito control efforts, thereby reducing the risk of CF transmission.

     Following recommendations from the World Health Organization and taking into account the local situation in Hong Kong, the FEHD sets up gravidtraps in districts where mosquito-borne diseases have been recorded in the past, as well as in densely populated places such as housing estates, hospitals and schools to monitor the breeding and distribution of Aedes albopictus mosquitoes, which can transmit CF and dengue fever. At present, the FEHD has set up gravidtraps in 62 survey areas of the community, with a surveillance period of two weeks. During the surveillance period, the FEHD will collect the gravidtraps once a week. After the first week of surveillance, the FEHD will immediately examine the glue boards inside the retrieved gravidtraps for the presence of adult Aedine mosquitoes to compile the Gravidtrap Index (First Phase) and Density Index (First Phase). At the end of the second week of surveillance, the FEHD will instantly check the glue boards for the presence of adult Aedine mosquitoes. Data from the two weeks of surveillance will be combined to obtain the Area Gravidtrap Index and the Area Density Index. The gravidtrap and density indexes for Aedes albopictus in different survey areas, as well as information on mosquito prevention and control measures, are available on the department’s webpage (www.fehd.gov.hk/english/pestcontrol/dengue_fever/Dengue_Fever_Gravidtrap_Index_Update.html#).

     The Hong Kong Special Administrative Region (HKSAR) Government today (May 21) announced to issue Red Outbound Travel Alert (OTA) for the Democratic Republic of the Congo based on public health considerations. Hong Kong residents should avoid non-essential travel there. For details, please refer to the OTA webpage of the Security Bureau (www.sb.gov.hk/eng/ota/index.html). In addition, the HKSAR Government announced on May 17 the activation of the Alert Response Level in accordance with the Preparedness and Response Plan for Ebola Virus Disease (the Response Plan). The relevant departments are fully prepared. Once a suspected case is identified, testing and comprehensive prevention and control measures will be implemented immediately in accordance with established protocols to prevent the spread of the virus in Hong Kong and protect public health.
      
     The HKSAR Government emphasised that no confirmed cases of Ebola disease have ever been recorded locally. At present, the risk of Ebola disease is primarily confined to outbreak areas and the immediate public health impact to Hong Kong is currently low.
      
Red Outbound Travel Alert
——————————
 
     The World Health Organization (WHO) recently declared that the Ebola disease epidemic in the Democratic Republic of the Congo and Uganda constituted a Public Health Emergency of International Concern. The scale of the outbreak in the Democratic Republic of the Congo showed signs of spread. It has spread to cities in the northern provinces, including Bunia and Goma, with increasing number of confirmed, suspected and fatal cases. Furthermore, there are currently no approved vaccines or treatments for the Bundibugyo virus involved in this outbreak. Local conflicts have also led to large-scale population movements. All of these factors have increased the risk of spread of the virus. The Department of Health (DH) has assessed the risk of local transmission spreading to other regions as very high. The HKSAR Government has therefore issued a Red OTA for the Democratic Republic of the Congo.
      
     Hong Kong residents in the Democratic Republic of the Congo who need assistance may call the 24-hour hotline of the Assistance to Hong Kong Residents Unit of the Immigration Department (ImmD) at (852) 1868, call the 1868 hotline using network data or use the 1868 Chatbot via the ImmD Mobile Application, send message to the 1868 WhatsApp and 1868 WeChat assistance hotline or submit the Online Assistance Request Form, or contact the Chinese Embassy in the Democratic Republic of the Congo at consular protection hotline: (243) 851474669. Hong Kong residents are encouraged to use the online Registration of Outbound Travel Information service (www.gov.hk/roti) of the ImmD to register their contact details and itinerary when outside Hong Kong. The information provided allows the DH and ImmD to disseminate practical information to them through appropriate means, including SMS on mobile phones, in a timely manner when necessary.
      
Strengthening screening to guard against imported cases
—————————————————————————–
 
     To prevent against imported cases, the DH has strengthened port health measures comprehensively. The DH has all along conducted health screenings for inbound travellers at all boundary control points. There are no direct flights between Hong Kong and the countries affected by the outbreak. However, as travellers may arrive in Hong Kong via other locations, primarily Addis Ababa, the capital of Ethiopia, from Africa, the DH has immediately strengthened health screenings for passengers arriving on flights from Addis Ababa. Staff have been deployed at arrival gates of the air-bridge to conduct temperature checks and health screenings for passengers disembarking from these specific flights.
      
     The DH is also broadcasting announcements in the airport arrival hall and through airlines to urge passengers who have visited the Democratic Republic of the Congo or Uganda within the past 21 days to proactively declare their travel history to the DH staff on site for further health assessment. From May 17 to 20, 11 individuals who declared having visited the relevant regions underwent health assessments by the DH. No suspected cases of Ebola disease were identified. The DH staff also provided these individuals with health information on the spot, reminding them to seek immediate medical advice at accident and emergency departments if they develop symptoms within 21 days of arrival in Hong Kong.
 
     The DH today sent another letter to all doctors in Hong Kong to remind them to remain highly vigilant. Any person who has travelled to affected areas (including the Democratic Republic of the Congo and Uganda) within the past 21 days and exhibits relevant symptoms must be managed as a suspected case and reported immediately to the Centre for Health Protection (CHP) via the 24-hour hotline provided in the letter.
      
     The Infection Control Branch of the CHP, in collaboration with the Infectious Disease Control Training Centre of the Hospital Authority (HA), will organise a seminar next week for healthcare professionals from both public and private medical institutions. The seminar will cover the latest situation regarding the Ebola disease outbreak, diagnosis, clinical management and infection control measures with a view to enhancing healthcare professionals’ understanding of the disease and their ability to respond effectively.
 
Testing and clinical management capabilities with high biosafety standards
———————————————————————————–
      
     Although the immediate public health impact of Ebola disease in Hong Kong is currently low, all relevant government departments have made the necessary preparations in case of occurrence of suspected or confirmed cases.
      
     The Public Health Laboratory Services Branch (PHLSB) of the CHP comprises laboratories with high biosafety standards, capable of conducting, testing for high-risk pathogens, and which also possess sufficient testing and genetic analysis capabilities and facilities. The PHLSB has procured laboratory reagents to perform testing for all suspected cases of Ebola disease. In collaboration with the HA, the DH has established procedures for handling high-risk specimens related to suspected cases to ensure that, should a suspected case arise in Hong Kong, testing can be conducted as quickly as possible to enable early detection and diagnosis, and prevent an outbreak.
      
     Currently, no preventive vaccine or antiviral treatment for the Bundibugyo virus has been developed worldwide. Should suspected or confirmed cases appear in Hong Kong, they will be referred to public hospitals under the HA for dedicated treatment, standardised diagnosis and follow-up managements, in order to fully safeguard public health and safety.
      
     The HA will continue to adopt the strategy of “early detection, early isolation, early notification”. The HA has reminded frontline healthcare workers to strengthen the screening for patients by gathering relevant information such as symptoms, contact history, occupation, and travel history, particularly in cases where patients exhibit relevant symptoms (such as fever, headache, myalgia, vomiting, diarrhea, rash, or severe signs of bleeding under skin) as well as whether the person has been to the Democratic Republic of the Congo and Uganda, has had close contact with a symptomatic person who recently traveled to these two countries, or has had close contact with a confirmed Ebola disease patient, within the past 21 days.
      
     If a suspected case is identified, the patient will be immediately transferred to the Hospital Authority Infectious Disease Centre (HAIDC) at Princess Margaret Hospital for isolation and treatment. The DH will be notified as soon as possible. The patient’s clinical specimens will be sent to the PHLSB for further testing. All suspected and confirmed Ebola disease cases will be admitted to the airborne infection isolation rooms (AIIRs) of the HAIDC. If necessary, the HA will also deploy AIIRs in various public hospitals to receive close contacts.
      
     The HA has also reminded frontline healthcare workers to remain vigilant and to strictly implement all infection control measures, including airborne, droplet, and contact precautions. Public hospitals currently have sufficient isolation facilities to receive patients requiring isolation, and there is ample stock of Personal Protective Equipment (PPE) to protect frontline healthcare workers. The HA has formulated contingency plans and clinical guidelines for frontline healthcare workers to refer to and will further strengthen training to ensure that frontline healthcare workers are familiar with the relevant procedures, including the donning and doffing of PPE, to reduce the risk of infection and safeguard the public.

     The DH also works closely with the Outbreak Control and Response Team (OCRT) of the Fire Services Department to ensure readiness for collaboration in handling and transporting patients suspected of being infected with high consequence infectious diseases. The OCRT is responsible for co-ordinating and implementing frontline response measures for high-risk infectious disease cases, including on-site risk assessments, infection control measures and interdepartmental co-operation. Relevant personnel have received specialised training. Furthermore, the OCRT’s Infection Control and Critical Care Transfer Ambulance is equipped with a high-efficiency negative pressure system and specialised equipment for critical care transport. When necessary, this ambulance can be deployed to handle cases related to high consequence infectious diseases, thereby effectively reducing the risk of transmission and providing appropriate support. This will further enhance Hong Kong’s overall response capacity for the current Ebola outbreak.
      
     In addition, the DH will follow established mechanisms to trace close contacts of confirmed or suspected cases. It has also inspected and ensured that the quarantine facilities (currently located at Penny’s Bay) are ready for use if necessary.
      
     Although no confirmed cases of Ebola disease have ever been recorded in Hong Kong, as an international city, Hong Kong remains vigilant and prepared for potential risks at all times. Last November, the DH conducted an interdepartmental exercise on Ebola disease to ensure that all stakeholders are familiar with the workflows and arrangements outlined in the Response Plan, thereby enhancing the HKSAR Government’s response capabilities for the prevention and control of infectious diseases.
 
Risk communication and community engagement
——————————————————-

     The CHP will continue to enhance risk communication and health education for the public via various online and offline channels, including press releases, social media posts and media interviews. In addition, the DH met with non-governmental organisations (NGOs) serving the African community in Hong Kong yesterday (May 20). Through these NGOs, the DH has conveyed relevant health information to Africans living in Hong Kong. The DH has also distributed health promotional materials at venues in Tsim Sha Tsui, where relatively more Africans stay.
      
     Ebola disease is a severe acute viral illness. Six viruses of the Ebola virus genus have been identified, including the BVD (Bundibugyo virus disease) involved in the current outbreak. The virus is transmitted to humans through close contact with the blood, secretions, organs, or other bodily fluids of infected animals. Human-to-human transmission resulting from direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other body fluids of infected people, and indirect contact with environments contaminated with such body fluids. According to information from the WHO, the average case fatality rates from past Ebola disease outbreaks was around 50 per cent.
      
     The HKSAR Government will continue to maintain close contact with the WHO, the Chinese Mainland, and other relevant health authorities, closely monitor the development of the Ebola disease outbreak, and adjust its prevention and control strategies as necessary.