Pest Control Steering Committee reviews progress of anti-mosquito work in combating chikungunya fever, and efforts in rodent control implemented by departments (with photo)
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Mosquito control
The representative of the Food and Environmental Hygiene Department (FEHD) reported to the PCSC the situation of mosquito proliferation this year thus far. The gravidtrap indices for Aedes albopictus from April to June 2025 (1.2 per cent in April, 8.6 per cent in May and 9.5 per cent in June) were lower than those in the same period in 2024 (4.2 per cent in April, 15.7 per cent in May and 14 per cent in June) and remained at a relatively low level. With the rainy season approaching, the FEHD has continued to intensify the mosquito prevention and control work with relevant government departments in areas under their purview, including eliminating mosquito breeding places, applying larvicides, conducting fogging operations to eradicate adult mosquitoes, and placing mosquito trapping devices at suitable locations. The FEHD will continue to conduct on-site inspections with relevant departments, and provide them with professional advice and technical support. The rainfall from April to June in 2025 was lower than the previous year, and with the effort of the Government and relevant stakeholders, the gravidtrap indices in some monitored areas reaching alert levels (zero in April, six in May and two in June) dropped compared with the same period in 2024 (one in April, 10 in May and four in June).
In spite of that, the rainfall in June 2025 reached 237.3 millimeters, which was higher than in April (57.1 millimeters) and May (81.6 millimeters). As the hot and rainy weather approaches, combined with the increase in inbound and outbound passenger traffic during the upcoming summer holiday, the overall risk of mosquito borne diseases may rise significantly. The departments will closely monitor the situation of mosquito infestation as reflected by the surveillance indices and strengthen mosquito prevention and control measures based on the recommendations discussed at the meeting, including constantly updating the list of mosquito infestation hotspots to adjust and plan their work based on the actual situation, to ensure that mosquito prevention and control work is prompt and effective.
It is worth noting that in addition to dengue fever, Aedes albopictus can also transmit chikungunya fever (CF). CF is a statutorily notifiable infectious disease in Hong Kong. Recently, a considerable number of CF infection cases have been reported in neighbouring regions and some overseas countries. As Hong Kong people frequently travel to and from different places, if a citizen is infected with CF abroad and is bitten by mosquitoes in Hong Kong during the infectious period, and subsequently the mosquitoes bite other people, local transmission may occur. In view of this, although there have been no CF cases in Hong Kong since 2020, the industry and the public must remain vigilant and intensify mosquito prevention and control efforts to avoid the risk of local cases during the summer.
Owing to the communicable disease notification mechanism established by Guangdong, Hong Kong and Macao, the Centre for Health Protection (CHP) of the Department of Health (DH) has kept abreast of the latest situation of CF in Guangdong Province. At the meeting, the CHP briefed the PCSC about the latest global situation and international response measures regarding CF, as reported by the World Health Organization.
The CHP has reminded the public to take precautionary and personal protection measures against mosquitoes, both locally and when travelling outside Hong Kong. The CHP's Port Health Division has stepped up inspections at the boundary control points to ensure good environmental hygiene and effective implementation of anti-mosquito measures. The Division also conducts temperature screening for inbound travellers. Any travellers with fever will be assessed on health conditions and referred to hospitals for follow up when necessary. The CHP will also maintain close liaison with relevant stakeholders, such as airlines and the travel industry, to provide the latest disease information and health advice in a timely manner. The CHP has set up a dedicated webpage on CF (www.chp.gov.hk/en/features/109029.html) to provide the public with relevant information.
In addition, the CHP has issued a letter to all doctors and hospitals in Hong Kong to provide them with the latest epidemiological information and appeal them to watch out for CF-related symptoms among those who return to Hong Kong from outbound travel. If CF cases are detected, they should be immediately referred to hospitals for treatment and reported to the DH in accordance with the established mechanism, so that the DH can initiate epidemiological investigations, and implement prevention and control measures. The Hospital Authority (HA) has reminded healthcare professionals to be vigilant in early identification of patients for timely diagnosis and management of patients. Once a suspected case is detected, the HA will activate the surveillance and notification mechanism and report the case to the CHP immediately.
Following Typhoon Wipha, the accumulation of stagnant water may have created mosquito breeding places, increasing the risk of mosquito infestation. Relevant departments and stakeholders will promptly launch a new round of actions to thoroughly eliminate mosquito breeding places, supplemented by fogging operations (i.e. ultra-low volume spraying) to eradicate adult mosquitoes. Subsequently, the departments will continue to take proactive anti-mosquito measures, including clearing potential breeding grounds at least once a week during the rainy season and timely co-ordination of fogging operations until the season ends, in a collective effort to safeguard public health.
Rodent control
Starting from 2024, the FEHD has fully adopted thermal imaging cameras with AI technology to conduct the Rodent Activity Survey (RAS) and establish a RAR in each district. The FEHD uses AI to analyse thermal images captured by cameras to detect and understand rodent pathways and activity ranges. This helps assess rodent infestation objectively and effectively to allocate resources precisely for targeted rodent control measures. The RAR in the second half of 2024 was 94 per cent (for every 100 images, 94 of them did not detect rodents), and the number of survey locations with RAR lower than 80 per cent has decreased by 10 as compared to the first half of 2024. From 2025, the FEHD's RAS has been extended to public housing estates and parks managed by the Housing Authority and the Leisure and Cultural Services Department. Relevant departments will have more data to enhance precision in rodent control work and make the survey more representative.
Making reference to the results of the RAS, the FEHD continues to strengthen rodent control and implement a series of targeted rodent prevention and control measures, including overnight anti-rodent operations and the application of new anti-rodent technologies and tools, which have gradually shown positive results. From January to June, 2025, the FEHD collected a total of approximately 57 200 live rodents, marking an increase of 92 per cent and 54 per cent as compared to the same periods in 2023 and 2024 respectively.
In the meeting, the FEHD briefed participants on how to make effective use of the RAR data to address rodent blackspots, and properly allocate resources to step up rodent prevention and control work so as to achieve a precise and effective rodent control strategy, for reference by relevant departments.
The effectiveness of prevention and control of rodents relies on the co-operation of stakeholders from various sectors. On December 31, 2024, the FEHD launched the first phase of the Anti-rodent Charter, targeting residential premises to raise residents' awareness of environmental hygiene and foster good habits to create a rodent-free environment. Residential premises that sign the Charter will be provided with free anti-rodent technical support from the FEHD, including invitations to attend pest control seminars organised by the department. As of June 15, 2025, 640 residential premises have signed the Charter, covering over 580 000 households. Two premises, with over 40 households, that signed the Charter have participated in the Pilot Scheme on Joint Property Management. Other participants joining the Pilot Scheme will be gradually invited to sign the Charter when they are ready.
The FEHD has actively provided technical support to residential premises that signed the Charter and organised 48 publicity and education activities over the past six months, including rodent control seminars, exhibitions and site visits, to encourage community participation in daily anti-rodent efforts. A total of approximately 2 150 people took part. Among these, two large-scale rodent control seminars held by the FEHD in March and June, 2025 were very well-received, attracting over 400 anti-rodent liaison ambassadors.
All departments agreed to continue to strengthen rodent prevention and control measures in premises under their respective management, to strengthen internal monitoring and assessment of the outcome of rodent control work, and to actively encourage relevant sectors and stakeholders to co-operate with the Government's work, eliminating rodents' fundamental survival conditions of food, harbourage and passages from their respective areas.
The second-stage environmental hygiene-related legislative amendments was passed by the Legislative Council on May 8, 2025 and will come into effect on August 17, to more effectively tackle rodent infestation and other environmental hygiene issues. The FEHD can now serve a "Notice of Elimination of Vermin" to persons responsible for management of the building (e.g. property management companies) when appropriate, for their follow-up action to eliminate vermin infestation in common parts of a building. Under the legislative amendments, the maximum penalty for non-compliance with "Notice of Elimination of Vermin" will be raised from a fine at level 2 ($5,000) and a daily fine of $100 to a fine at level 4 ($25,000) and a daily fine of $450, so as to enhance deterrent effect.
The meeting was chaired by the Under Secretary for Environment and Ecology, Miss Diane Wong. Participants of the meeting came from three policy bureaux and 20 government departments and organisations.
Ends/Wednesday, July 23, 2025
Issued at HKT 22:32
Issued at HKT 22:32
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