When Andrew Fletcher, from London, went travelling in India he made sure he got the full range of jabs for his trip.
His temperature soared, particularly at night and he started developing headaches.
His GP suspected that he had malaria, but Andrew checked himself into the Hospital for Tropical Diseases, in London, where after a series of blood tests doctors found he had paratyphoid.
"The reason I think I was admitted was that there was some degree of uncertainty about what I had. They looked at malaria and typhoid as well.
"I had a full course of jabs in India, including typhoid, but I have subsequently learned that it is not anywhere near 100% effective, which few people are told when they have a jab.
"It came as a surprise because when the word typhoid was first bandied around I got quite sensitive and said I had a typhoid injection."
There are about 17 million cases of typhoid each year globally and about 600,000 deaths.
Typhoid is generally spread through poor hygiene and contaminated food and water.
Paratyphoid is a similar infection, but the symptoms tend to be milder.
Andrew said that although he was shocked to learn that he had paratyphoid, that he was relieved to know what was causing his ill-health.
"When I first got here I felt dreadful. Psychologically it is much better to know what it is, even though it is not a pleasant thought."
Andrew said that at its peak the disease had left him drained.
"For half the day I feel OK and for half the day I have a high temperature. It is more a feeling of being wiped out. I have a very short attention span.
"I feel I don't even have the energy to read a magazine and watch a film".