You've Got What? Typhoid and paratyphoid
PDF 93 KB
These are systemic illnesses caused by the bacteria Salmonella Typhi (typhoid) or Salmonella Paratyphi (paratyphoid).
Typhoid and paratyphoid are notifiable conditions1
Salmonella Typhi lives only in humans. People with typhoid fever carry the bacteria in their bloodstream and gut. In addition, a small number of people, called carriers, recover from typhoid fever but continue to carry the bacteria. Both ill people and carriers shed Salmonella Typhi in their faeces and urine.
The bacteria are spread by eating food or drinking water contaminated by faeces or urine of patients and carriers. Common sources are:
If fruit and vegetables are washed in contaminated water they may cause illness.
Typhoid is common in areas of the world where hygiene standards are poor and water is likely to be contaminated with sewage. These illnesses are no longer common in developed countries, with most cases occurring in areas such as:
Onset of illness is gradual, with:
Illness varies from mild with low-grade fever, to severe with multiple complications.
People who do not get treatment may continue to have fever for weeks or months, and as many as 20% may die from complications of the infection. With treatment, the death rate falls to about 1%. Paratyphoid has similar symptoms to typhoid, although the illness tends to be milder.
Diagnosis is made by growing the bacteria from the blood or bone marrow early in the illness. Later in the illness the bacteria can sometimes be grown from urine or a faecal sample or detected using a PCR (polymerase chain reaction) test in a pathology laboratory.
(time between becoming infected and developing symptoms)
From 3 days to more than 60 days; usually
(time during which an infected person can infect others)
As long as the bacteria are shed in the faeces or urine, usually from the first week of illness until completely recovered. About 10% of untreated typhoid patients will be infectious for 3 months after onset of symptoms and 2 to 5% become permanent carriers. Fewer people with paratyphoid become carriers.
Antibiotic treatment is available and is necessary, particularly in severe cases. Antibiotic treatment can reduce carriage (for example, the bacteria is still present in the bowel and the person has no symptoms but can still pass on the infection to others). People given antibiotics usually begin to feel better within 2 to 3 days and deaths rarely occur. Resistance to available antibiotics is increasing, so it remains important to take care to prevent yourself from being infected.
1 – In South Australia the law requires doctors and laboratories to report some infections or diseases to SA Health. These infections or diseases are commonly referred to as 'notifiable conditions'.