Communicable Diseases Series Causative agents Management Cook food thoroughly Keep the kitchen, cooking and eating utensils clean Typhoid and paratyphoid fevers are caused by the bacteria Infected individuals should seek medical Use separate utensils (e.g. knife and chopping board) to handle raw food and cooked food or Salmonella Typhi and Salmonella Paratyphi respectively. advice for management. The infection can be effectively treated by antibiotics. Symptomatic ready-to-eat food treatment such as fluid replacement and adequate rest is Hygienic food storage environment also important. Strict personal hygiene should be observed in order to prevent transmission of the bacteria Take food promptly after cooking. Perishable foods Clinical features to others. The majority of patients can fully recover after that has been kept at room temperature for more treatment. However, about 2 to 5% of patients will become than 4 hours should be discarded Typhoid fever is a systemic infection that carriers of the bacteria and they may require long-term follow-up. Choose ready-to-eat, cooked or perishable that are can affect many organs. Common symp- stored correctly, e.g. hot food at above 60°C, cold toms of typhoid fever include prolonged food at or below 4°C, frozen food at or below -18°C fever, headache, malaise, nausea, abdomi- nal pain, loss of appetite and constipation or diarrhoea Prevention If perishable food is not consumed immediately, (in adults, constipation occurs more often than keep it at 4°C or below. Keep it well covered diarrhoea). In some cases, rose-coloured spots appear 1. Maintain good personal hygiene Handle and store raw and cooked food separately. on the trunk and enlarged spleen and liver can be Perform hand hygiene frequently, Store raw meat, poultry, and seafood below detected. In severe cases, there may be life-threatening especially before handling food or ready-to-eat food or cooked food in the fridge to prevent juices from dripping onto ready-to-eat food intestinal bleeding and perforation. Apart from symptomatic eating, and after using the toilet or handling faecal matter patients, some asymptomatic infected individuals are or cooked food Wash hands with liquid soap and water, and rub for at able to shed bacteria in their faeces or urine. In addition, Clean refrigerator regularly. Check the temperature a small number of people, called carriers, continue to least 20 seconds. Then rinse with water and dry with a of the refrigerator with a thermometer and ensure shed the bacteria in their faeces after recovery from the disposable paper towel or hand dryer. If hand washing the fridge is kept at or below 4°C and freezer at or disease. Paratyphoid fever presents a similar clinical facilities are not available, or when hands are not visibly below -18°C picture but the illness tends to be milder. soiled, hand hygiene with 70 to 80% alcohol-based handrub is an effective alternative If necessary, refrigerate cooked leftovers and consume as soon as possible. Reheat thoroughly Wear gloves and a surgical mask while disposing of or before consumption. Discard any spoilt food items handling vomitus and faeces, and wash hands thoroughly Mode of transmission afterwards * Please visit the website of Centre for Food Safety for Exclude infected persons and asymptomatic carriers from more information on food safety. handling food and from providing care to children, elderly Typhoid and paratyphoid fevers are 3. Others mainly transmitted via the faecal-oral and immunocompromised people route. The causative bacteria are passed in Immunisation for typhoid fever is not routinely Refrain from work or attending class at school, and seek recommended. Even vaccinated individuals should the faeces and urine of infected people, which medical advice if suffering from vomiting or diarrhoea may contaminate food, water or beverages and cause take care to avoid consumption of potentially infection in those who have consumed the contaminated 2. Maintain good food hygiene contaminated food and water as the vaccine does items. Types of food which are susceptible to Adopt the 5 Keys to Food Safety in handling food, i.e. Choose not provide full protection from infection contamination include shellfish (particularly oysters), (Choose safe raw materials); Clean (Keep hands and utensils Travellers who visit endemic areas of typhoid fever raw fruits and vegetables and unpasteurised milk and clean); Separate (Separate raw and cooked food); Cook are advised to consider vaccination. For more dairy products. Transmission through sexual contact, (Cook thoroughly); and Safe Temperature (Keep food at safe information, please visit Travel Health Service especially among men who have sex with men, has temperature) to prevent foodborne diseases. website at https://www.travelhealth.gov.hk/ rarely been documented. Careful procedures of cooking and preparing food Drink only boiled water from the mains or bottled drinks from reliable sources Centre for Health Protection Website Wash fruits and vegetables thoroughly under clean www.chp.gov.hk Incubation period running water and avoid those with damaged skin Health Education Infoline of Scrub and rinse shellfish in clean water. Remove the For typhoid fever, the incubation period viscera before cooking, if applicable. Heating to an the Department of Health ranges from 3 to 60 days and is usually internal temperature of 90°C for 90 seconds is required 2833 0111 7 to 14 days. The incubation period for for cooking of molluscan shellfish. If possible, remove Centre for Food Safety Website paratyphoid fever is usually 1 to 10 days. the shells before cooking as they impede heat penetration. Otherwise, boil at 100°C until their shells open; boil for www.cfs.gov.hk additional three to five minutes afterwards. Discard any shellfish that do not open during cooking Revised in November 2019.