Typhoid is caused by Salmonella typhi, a bacterium from the same genus that causes salmonella food poisoning.
Highly contagious, typhoid is spread through contact with infected people’s faeces and (occasionally) urine. This makes it very common in countries with poor sanitation, where human waste can find its way into sources of drinking water and the food chain.
If caught early, typhoid symptoms will usually be mild and clear up within two weeks. However without treatment, roughly one in five cases of typhoid is fatal, while those surviving may have permanent physical or mental disabilities. This is why a typhoid fever should be treated as quickly as possible with a course of antibiotics. Serious cases of typhoid will require hospital treatment and a course of antibiotic injections.