Replies to LegCo questions

LCQ9: Prevention and control of biting midges

Following is a question by the Hon Chan Han-pan 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 just past broke the record for the most humid April in the past 55 years, and a humid environment provides favourable breeding grounds for biting midges. Biting midges are insects smaller than mosquitoes in size and usually appear in groups, and as a result, persons who get bitten often have a few dozens of red swollen spots on their bodies. Moreover, it is learnt that like mosquitoes, biting midges can transmit disease. Previous overseas cases show that the saliva of biting midges may possibly trigger allergic reaction in persons who get bitten. Those in serious condition may suffer from shock and even die. In this connection, will the Government inform this Council:

(1) of the respective numbers of complaints received by the authorities about the problem of biting midges in each of the past three months and in each of the past three years;

(2) whether the authorities have kept records on the transmission of communicable diseases by biting midges, e.g. dengue fever, Japanese encephalitis and Zika virus; if they have, of the details; if not, the reasons for that;

(3) given that various types of trapping stickers for biting midges are currently available for sale on the market, whether the authorities have used such trapping stickers in public places; whether they have conducted any study on the effectiveness of the various brands and types of trapping stickers for biting midges; if they have, of the details; if not, the reasons for that; and

(4) whether the authorities will formulate preventive measures in the near future, and draw up medium and long-term plans to address the problem of biting midges; if they will, of the details; if not, the reasons for that?

Reply:

President,

(1) Annex 1 gives the number of complaints about the problem of biting midges received by the Food and Environmental Hygiene Department (FEHD) in each of the past three years and each of the first four months in 2016.

(2) Biting midges are not vectors for mosquito-borne diseases such as dengue fever, Japanese encephalitis and Zika Virus Infection. Midges found in Hong Kong are not major vectors of any vector-borne diseases.

(3) and (4) Different products are available in the market for mitigating the nuisance caused by biting midges. Members of the public may choose suitable products according to their individual needs and follow the instructions for use as stated on the product labels. Currently, FEHD is carrying out control work in public places by means of environmental methods to reduce the breeding places for midges. Fogging would also be carried out as necessary to alleviate the nuisance. FEHD does not use "trapping stickers" for capturing midges.

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. 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.

Proper and regular maintenance of vegetation around households and gardens could help minimise or prevent breeding of biting midges in these areas. 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. 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).

In addition, 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 smaller than 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 2 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: http://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 16:55

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LCQ9 Annex 1
LCQ9 Annex 2