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Bệnh lao là gì?

Typhoid and paratyphoid fever are bacterial infections, collectively known as enteric fever and are caused by the bacterias Salmonella enterica subspecies serovars Typhi and Paratyphi A, B and C. Enteric fever is different to the gastroenteritis that can be caused by Salmonella. Symptoms of enteric fever can range from mild to severe, and if left untreated can lead to serious complications or death. Typhoid fever presents more commonly than paratyphoid fever and is associated with higher rates of severe complications and poorer outcomes.

Triệu chứng cần nhận biết

Infections caused by typhoid and paratyphoid often present with prolonged fever and fatigue, headache, splenomegaly (enlargement of the spleen), and abdominal symptoms such as pain, lack of appetite, constipation or diarrhoea; often with bacteremia (bacteria in the bloodstream). A rash appearing as small pink clusters on the skin known as ‘rose spots’ can be seen in up to 30% of individuals with enteric fever. In severe cases, complications can include septic shock, gastrointestinal bleeding with perforation, altered conscious state, and death.

Bệnh lây truyền qua đường nào

Typhoid fever is transmitted via the faecal-oral route and via contaminated food and water sources, most commonly in developing countries with untreated drinking water and poorer sanitation and food handling practices. The incubation period is usually 7-14 days.

Approximately 1 in 20 infected individuals who do not receive treatment for typhoid fever will become an asymptomatic carrier of the disease.

Dịch tễ học

Whilst not as prevalent in Australia, typhoid fever is a common infective illness in many parts of the world, especially Asia, southeast Asia and sub-Saharan Africa. There were 14.3 million cases of typhoid and paratyphoid fever in 2017, with an estimated global case fatality of 0.95%. Children are disproportionately affected by infection.

Phòng ngừa

Prevention of enteric fever includes both vaccination and undertaking food and water precautions whilst travelling in developing countries where typhoid is endemic. There is no specific vaccine for paratyphoid fever however there is some evidence to suggest that administration of the oral typhoid fever vaccine can provide some cross protection against paratyphoid fever.

Vắc-xin

There are 3 vaccines available in Australia for protection against typhoid fever:

^§Whilst not registered for use in this age group, a number of travel medicine practitioners routinely administer Vivaxim® to children aged 2-15 years. Refer to Lau C. et al The tolerability of a combined hepatitis A and typhoid vaccine in children aged 2-16 years: an observational study Journal of Travel Medicine 2016: 15, 23 (2) để biết thêm thông tin.
*If a patient is taking both Vivotif® oral and the oral cholera vaccine (Dukoral®), these should be administered 8 hours apart due to the risk of components of the cholera vaccine impacting how the typhoid vaccine is absorbed in the gut.
^Not to be given to people who are immunocompromised, taking immunosuppressive medications, pregnant women, or those taking oral antibiotics.

Other precautions

In addition to vaccination, travellers should also maintain the following precautions to limit exposure to infections:

• undertaking effective hand washing practices
• drinking bottled or boiled water
• avoiding high-risk foods and drinks including:
  • raw (or undercooked) shellfish
  • cold meats
  • salads
  • untreated water and ice in drinks.

Nguồn tài liệu

• Australian Immunisation Handbook: Typhoid fever
• The blue book: guidelines for the control of infectious diseases
• World Health Organization: Typhoid