Dermatology Made Easy is based on the most popular topics from DermNet NZ's vast array of material. The book combines the essential focus of the ‘Made Easy’ book series with the authority and knowledge base of DermNet NZ's unparalleled resources.
Author: Daniel Wong, Intern, Monash Medical Centre, Victoria, Australia; Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, March 2014.
Typhoid fever, also known as enteric fever, is an infection caused by Salmonella typhi. The symptoms of typhoid fever are nonspecific and can include:
Paratyphoid fever is an infection caused by Salmonella paratyphi, and can present similarly to enteric fever.
Both typhoid and paratyphoid fever are examples of salmonellosis, where the infectious agent originates from the genus of motile bacteria with a gram-negative staining pattern on microscopy, Salmonella.
Typhoid fever is contracted through contact with infected individuals and chronic carriers of typhoid fever (who are in good health but salmonella bacteria can be found in their faeces). Salmonella bacteria primarily infect humans and are transmitted through ingestion of contaminated water or food. This usually occurs in developing countries with poor hygienic practices.
Typically, individuals may have recently travelled to endemic areas (South East Asia, South America), ingested contaminated food or water, and experienced some of the symptoms listed above. The Salmonella bacteria can be found in faeces or blood. There may also be a rise in antibody levels observed in the blood.
Rose spots describe the rash that occurs in up to 30% of people infected with Salmonella typhi. Characteristically, rose spots are seen in untreated typhoid fever.
Rose spots are thought to be bacterial emboli to the skin, i.e. clumps of bacteria have spread through the bloodstream.
Rose spots have also been described in other infections (psittacosis, brucellosis, shigellosis, streptobacillosis, and leptospirosis).
Apart from rose spots, other rashes may arise in salmonella infections.
However, S. Typhi is commonly resistant to several antibiotics, including cotrimoxazole, ampicillin, and chloramphenicol, and sometimes quinolones (eg ciprofloxacin).
Ceftriaxone, and azithromycin appear to be effective.
Prevention of typhoid fever is mainly achieved through vaccination and avoidance of high-risk foods.
Travellers to at risk countries, eg South America and South East Asia, are strongly recommended to be vaccinated in advance of travel. Two forms are available:
If vaccinated previously, immunity can be checked by a blood test. Vaccine effectiveness declines with time. A booster may be necessary.
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