Press Release

Cholera cases under control

June 22, 2001

Prompt and concerted efforts by the Department of Health (DH) and the Food and Environmental Hygiene Department (FEHD) have successfully brought under control the recent incident of cholera cases.

The Consultant (Community Medicine) of the Department of Health (DH), Dr Tse Lai-yin said this today (June 22).

"Of the six confirmed local cholera cases reported between June 5 and 11, all patients have recovered completely and discharged from hospital."

"However, we should remain vigilant because cholera is endemic in Hong Kong."

"Members of the public are reminded that the best way to prevent cholera and other food-borne diseases is to observe good personal, food and environmental hygiene at all times," Dr Tse said.

DH and FEHD had completed their joint investigations into the six cholera cases.

Dr Tse said: "We had identified a number of irregularities in food preparation and lapses in hygiene standards, both at home and at food premises. These irregularities could have contributed to the occurrence of these cases."

Irregularities detected at home include:

• Raw food was placed above uncovered cooked food in the refrigerator. As a result, juices from the raw food might have dripped down and contaminated the cooked food below. Raw food should be kept below cooked food in the refrigerator, and both should be covered.
• Refrigerators were jampacked with food, with one having a cabinet temperature as high as 13 degrees Celsius.
• Fish was inadequately cleaned and cooked in the rice cooker for insufficient time.

Irregularities detected in food premises include:

• Some refrigerators in the food premises were congested with food with high temperature. A chiller for storing sashimi (Japanese raw fish) had a temperature of 18 degrees Celsius.
• Keeping of raw seafood in close proximity to uncovered cooked food in the refrigerator. In some food premises, the same chopping board was used for both raw seafood and cooked food. These practices increased the chance for cross contamination.

Dr Tse said the patients' homes had been promptly and thoroughly disinfected to prevent secondary spread of the disease and health education had been given.

Owners and operators of food premises had been given advice on food and environmental hygiene and asked to take immediate measures to rectify the irregularities. Follow-up inspections had also been carried out to ensure that all recommendations had been complied with.

DNA fingerprinting was performed on the isolates from the six patients.

Dr Tse said: "DNA fingerprinting of these six isolates showed an identical pattern. It is similar to the local cases that occurred in 2000."

"However, the strain in this incident is different from those cases contracted in the Mainland and other countries."

"The results indicate that these cases had been contracted locally. A common source for the six cases could not be ruled out."

A total of 2,050 samples were taken for microbiological testing. These included 512 stool specimens from related people, 289 food samples, 811 water samples, and 438 environmental samples.

In response to the cholera cases, FEHD staff conducted large -scale inspections of food premises throughout the territory. During the period of June 10-12, a total of 704 verbal warnings and 242 summonses were issued to operators of food shops for breaching relevant hygiene regulations while 2,670 kg of uncovered food with risk of contamination were seized and disposed of.

All samples were negative for cholera, except for two positive environmental swabs taken from the toilets used by two patients before disinfection.

Dr Tse said: "In looking for the source of infection, our investigations had covered seafood, processed foods, meats and vegetables, water and ice, fish tank water, food premises and food factories, and food handlers."

"However, in a place where cholera is endemic like Hong Kong, it is not unusual that the source might not be found despite extensive investigations."

To prevent getting the disease, Dr Tse said members of the public should :

• Clean food thoroughly and ensure they are adequately cooked before consumption;
• Wash hands before eating and after going to toilets;
• Handle raw and cooked food with separate utensils;
• Keep raw and cooked food separately;
• Store food in refrigerator at 4 degrees Celsius or below and adequately reheat leftover food before consumption;
• Keep the environment clean; and
• Avoid patronizing unlicensed food premises and hawkers.

Public education and publicity have also been further enhanced to reinforce the preventive measures at home and food premises. Announcements in the Public Interest (APIs) on "Prevention of Cholera", "Food Hygiene at Home" and "Food Hygiene in Restaurant" are broadcast daily on all TV stations.

To-date seven confirmed cholera cases were reported in Hong Kong in 2001. The first one was an imported case in May.