Replies to LegCo questions

LCQ20: Biting midges

Following is a question by the Hon Chan Hak-kan and a written reply by the Secretary for Food and Health, Dr Ko Wing-man, in the Legislative Council today (June 8):

Question:

It has been reported that the April of this year is the most humid April in the past 55 years, and a humid environment provides favourable breeding grounds for biting midges. Recently, swarms of biting midges have been found in a number of artificial turf football pitches and parks under the management of the Leisure and Cultural Services Department. It is learnt that the saliva secreted by female biting midges during blood sucking will cause swollen and itchy skin or trigger allergic reaction, and may even contain pathogens such as viruses, parasites, etc. As there have been overseas cases of fatal anaphylactic shock triggered by midge bites, some members of the public consider that the Government should actively prevent and control biting midges. In this connection, will the Government inform this Council:

(1) whether it knows the number of cases from January to May this year in which members of the public fell sick due to midge bites and sought medical consultation; if it knows, of the number of cases and how such number compares with that in the same period of last year;

(2) given that the authorities are currently implementing an enhanced dengue vector surveillance programme for monitoring the distribution of Aedes albopictus at selected areas, whether the authorities will consider implementing a surveillance programme targeting at biting midges; if they will, of the details; if not, the reasons for that;

(3) whether the authorities will launch a large-scale anti-midge campaign; if they will, of the details, including the types of insecticide sprays to be used; if not, the reasons for that; and

(4) whether the authorities will step up their efforts in public education to publicise among the public ways to prevent midge bites; if they will, of the details; if not, the reasons for that?

Reply:

President,

(1) The Hospital Authority does not keep statistics showing the number of persons who seek medical consultation after having been bitten by biting midges.

(2) and (3) Biting midges are not vectors for mosquito-borne diseases such as dengue fever, Japanese encephalitis and Zika Virus Infection. Currently, the World Health Organization has not published guidelines for systematic surveillance of biting midges. According to our understanding, other places like the Mainland, Taiwan, Singapore, Malaysia as well as countries in America and Europe have not formulated any surveillance programmes for biting midges. The Food and Environmental Hygiene Department (FEHD) will keep a watching brief over the measures or studies that are being carried out in other places for putting biting midges under surveillance, including the opinion of the experts in this field. Depending on the circumstances, FEHD would consider whether the practices being pursued elsewhere should be applied in Hong Kong.

Midges found in Hong Kong are not major vectors of any vector-borne diseases. In response to the biting midges problems which recently prevail, FEHD will continue to monitor the infestation of biting midges in public places through various channels, including regular inspection carried out by frontline staff and handling of complaints. FEHD will enhance its control measures when necessary. FEHD has also advised the relevant government departments, such as the Leisure and Cultural Services Department, Highways Department, Housing Department and Education Bureau, to strengthen control over biting midges in areas under their management (e.g. parks, roadside slopes, housing estates and schools).

Infestation of biting midges is seasonal and localised. The peak season for biting midges activities usually occurs in the humid and warmer months each year. Scrubby areas with lots of decaying vegetation are their typical habitats. Specific environmental control actions in these areas targeting at reducing their breeding places can effectively control infestation of midges. Routine anti-mosquito work and environmental improvement measures carried out by FEHD such as removal of fallen leaves, decaying vegetation, silt in sand traps and surface channels help control infestation by reducing the number of breeding places for midges. Where necessary, fogging will be conducted at the infested areas in order to minimise the nuisance, and the department also carries out environmental improvement measures to remove possible breeding places for midges.

Where the infestation of midges occurs at private places, FEHD is willing to provide technical advice to the relevant parties that would help them carry out effective measures for controlling biting midges. For households, proper and regular maintenance of vegetation around households and gardens could help minimise or prevent breeding of biting midges in these areas.

(4) Meanwhile, FEHD has strengthened its efforts to educate the public on how to prevent and control biting midges infestation. For example, the department is disseminating information to stakeholders in housing estates and schools, helping to enhance the effectiveness of their endeavours to control and prevent midges. Members of the public are advised to take appropriate personal protection measures to minimise the nuisance caused by midges. Such personal protection measures include the installation of appropriate screens (mesh size <0.75 mm), wearing long-sleeve clothing and applying insect repellents with DEET according to label instructions. Natural insect repellents may help repel midges to a certain extent, though the effect is less persistent given their high evaporability. Attached at Annex is a copy of the information leaflet that FEHD has prepared for the general public on matters relating to the control and prevention of biting midges. Members of the public may visit the following websites for more information on the subject: www.fehd.gov.hk/english/safefood/risk-pest-arthropod.html#biting_midges and www.fehd.gov.hk/english/safefood/library/pdf_pest_control/Biting_Midges.pdf.

Ends/Wednesday, June 8, 2016
Issued at HKT 17:31

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LCQ20 Annex