CHP urges vigilance against communicable diseases in new school year

     The Centre for Health Protection (CHP) of the Department of Health (DH) today (August 22) urged schools, parents and students to heighten vigilance and adopt strict personal and environmental hygiene as well as mosquito control actions and personal protective measures to prevent the spread of dengue fever (DF) and other communicable diseases in schools as social contact among students in schools will increase when school resumes after the summer holidays.
 
     A spokesman for the CHP said, "Hong Kong has experienced an unprecedented outbreak of DF since August 14. As the situation is still evolving, it is likely further cases may occur in the community. The CHP calls for assistance from schools in the prevention of DF."
 
     "As schools are collective assembly places, infectious diseases could be easily spread among people through their daily contacts. Based on seasonal patterns and past surveillance data, we expect that sporadic institutional outbreaks of respiratory illnesses or hand, foot and mouth disease (HFMD) or chickenpox may occur in the new school year when students and staff gather on campus," the spokesman continued.
 
     "The CHP has issued letters to schools, kindergartens and child care centres today to remind them for continued vigilance and reinforcement of preventive measures to guard against possible outbreaks when classes resume," the spokesman added.

A. Dengue fever

     To reduce the risk of DF infections, apart from general measures, the CHP reminded schools, parents, staff and students that they should not visit Lion Rock Park during the closure period in order to prevent contracting DF. Scientific studies have shown that infected persons can transmit the virus to mosquitoes through mosquito bites even if they remain asymptomatic or before their onset of symptoms, leading to further spread of the disease. Hence, people who had visited Lion Rock Park are advised to apply insect repellent for 14 days upon their last visit.
 
     Likewise, staff and students returning from affected areas of DF should apply insect repellent for 14 days upon arrival in Hong Kong. Those with DF symptoms should seek medical advice as early as possible.

     Eighteen local cases of DF had been confirmed this year as of yesterday. Excluding the local cases, as of yesterday, 61 imported cases had been recorded in 2018. The cases were mainly imported from Thailand (26), the Philippines (12) and Cambodia (seven).
    
     Prompt, continuous, intensive and effective anti-mosquito operation must be carried out at this stage to prevent DF from further spread. Schools should take the following preventive measures to prevent accumulation of stagnant water and eliminate mosquito breeding sites:
 

• Put all used cans and bottles into covered dustbins;
• Change water for plants at least once a week, avoid using saucers underneath flower pots;
• Cover tightly all water containers, wells and water storage tanks;
• Keep all drains free from blockage; and
• Top up all defective ground surfaces to prevent the accumulation of stagnant water.

 
     Staff and students are also advised to protect themselves from mosquito bite by taking the following measures:
 

• Wear loose, light–coloured, long-sleeved tops and trousers, and apply effective mosquito repellent containing DEET to exposed parts of the body and clothing;
• Use mosquito screens or bed nets when the room is not air-conditioned; and
• Place anti-mosquito devices near entrances such as windows and doors to prevent mosquitoes from entering indoor.

 
     Furthermore, the school management is advised to appoint designated staff for mosquito prevention and control in the school premises. Details are available from the guidelines published by the Food and Environmental Hygiene Department:
www.fehd.gov.hk/english/pestcontrol/library/pdf_pest_control/mosquito_school.pdf.
 
 
B. Influenza and respiratory illnesses

     The surveillance data of the CHP showed that the overall local influenza activity is currently at a low level, but outbreaks of influenza-like illness in schools may increase after the start of the new school year. Although influenza is usually self-limiting, it may cause serious illness even in healthy children.
 
     Parents are advised to consult family doctors for seasonal influenza (SI) vaccination for their children for personal protection before the winter season arrives. Parents are reminded that it takes two weeks for the body to develop a sufficient level of antibodies to protect against influenza virus infection after vaccination.

     "If students or staff develop fever, respiratory symptoms, diarrhoea, vomiting or skin rash, schools should strongly advise them not to return to campus and to promptly seek medical advice. Management of schools should observe precautions on campus, such as avoiding sharing clothing or slippers, to prevent possible transmission of diseases," the spokesman added.

     For more information on SI vaccination, parents may call the CHP hotline at 2125 2125 or visit the CHP's Vaccination Schemes page. 
 
 
C. Hand, foot and mouth disease and enterovirus infection

     Although local HFMD activity returned to a baseline level in mid-August after its peak in June, sporadic outbreaks may occur in schools and institutions where HFMD can easily spread among young children with close contact. A smaller peak may also occur from October to December.

     In 2018, 33 cases of enterovirus (EV) 71 infection had been recorded as of yesterday, which is fewer than the 44 cases in the same period of 2017; whereas five cases of severe paediatric EV infection (other than EV71 and poliovirus) were recorded in 2018 as of yesterday, which is more than the three cases in the same period of 2017. The five infants this year involved children aged 1 to 2 months and each of them was diagnosed with meningitis.
 
     "EV infection is transmitted by direct contact with nose and throat discharges. Children suffering from EV infection should stay at home and avoid contact with other children until they have recovered," the spokesman reminded.

D. Chickenpox

     Chickenpox is the most common notifiable infectious disease in Hong Kong and is highly communicable, which can be spread through droplets or air. It can also spread through direct or indirect contact with the discharges from vesicles and mucous membranes of persons with chickenpox or herpes zoster. Children are most affected. Locally, there are two seasonal peaks. The number of chickenpox cases usually starts to rise in October and peaks in December and January, while a smaller peak is also observed in June and July.

     A total of 225 institutional chickenpox outbreaks affecting 1 138 persons had been recorded in 2018 as of August 17, including 79 outbreaks (363 children) in kindergartens or child care centres and 117 (673 pupils) in primary schools. On the whole, 4 124 chickenpox cases had been reported this year, which is fewer than the 6 551 cases in the same period last year.

     Schools are reminded to follow the Guidelines on Prevention of Communicable Diseases on preventive and control measures as well as management of outbreaks, which should be reported to the CHP for prompt follow-up. Schools may refer to the CHP's pages on DF, SI, HFMD and EV71 infection and chickenpox and for more information.