Figures recorded by the Health Authority Abu Dhabi and published in the latest Communicable Diseases Bulletin.
Reported typhoid cases double in the past year
ABU DHABI // Reports of typhoid have more than doubled in the first quarter of 2012 compared with the same period last year.
The case figures were recorded by the Health Authority–Abu Dhabi (Haad) and published in the latest Communicable Diseases Bulletin.
Reported cases of typhoid from January to March of this year were 130, compared with 55 over the same period in 2011.
Other foodborne illnesses, such as diarrhoea and respiratory infections, did not rise as much, but did increase from 197 to 253.
This has been partly attributed to a rise in the number of people contracting the rotavirus that causes gastroenteritis. Rotavirus infection accounted for almost half the total number of cases.
About 14 per cent of typhoid cases were found to have originated outside of the country, in areas where the disease is rampant.
"That 14 per cent [of cases] travelled to risky areas was proven. The vast majority travelled to and from Southern Asia, an area well-known to be highly endemic," said Dr Ghada Yahia, a senior regional officer with Haad's communicable diseases section who worked on the bulletin.
People should be wary when visiting Southern Asia, said Dr Asim Malik, a consultant and chief of infectious disease at Mafraq Hospital in Abu Dhabi.
"The bulk of the disease exists in this part of the world.
"Subsequently, travel through those countries is a significant risk and typhoid can be acquired via contaminated water or food items that you may purchase from a street vendor."
The increase in foodborne illnesses was to be expected, said Dr Yahia. "Rotavirus is seasonal, rising especially from December to June, and that's what happened [in our records]."
As a result, a rotavirus vaccine will be included in the Haad immunisation schedule for children under the age of one from this time next year.
This new data will help authorities pinpoint areas of weakness, said Mohamed Jalal Al Rayaysa, the director of communication and community service for The Abu Dhabi Food Control Authority, which works alongside Haad whenever foodborne illnesses which occur outside of the home are found. "These are very important figures for us. This encourages more work for both sides to highlight the important message of how to deal with food and food consumption," Mr Al Rayaysa said.
When it comes to the reported increase in typhoid, this does not signal any problems, said Dr Yahia.
Unreliable methods of testing for the infectious disease may have lead to the authority over-inflating the prevalence of it within the Abu Dhabi community, she said.
"Most of the cases reported were only found using a Widal test. This can lead to a big over-estimation of the confirmed number of typhoid fever cases."
A Widal test consists of mixing the bacteria responsible for causing typhoid with certain antibodies from the infected person.
Through further investigation, using blood cultures, only 10 per cent of the 130 cases recorded at the beginning of this year were confirmed. The vast majority (88 per cent) were only diagnosed using the Widal test, which decreases their validity.
Through continued campaigns, the number of false-positive cases should fall, said Dr Yahia.
"We specify what to report as expected and what to report as confirmed."
Referred to as a febrile illness, in that it is onset by a sudden fever, a person will not normally begin to show symptoms of typhoid fever until about two weeks after contracting salmonella typhi, the bacteria from which typhoid takes its name.
Symptoms include fever, abdominal pain or delirium, depending on the stage of the disease.
Most patients who are seen at Mafraq present at this stage. If left undetected for more than three weeks, further complications can arise, said Dr Malik.
"At times patients can develop meningitis, pneumonia and even abscesses in various parts of the body like the liver or spleen."
The mortality rate among untreated patients is between 10 and 20 per cent, but death is a rare end result, said the doctor.
Overall, the continued efficiency with which records are collected by Haad will continue to shape the future of health care in the emirate, said Dr Yahia.
"These records provide us with evidence on which we can make changes.
"This information gives us early warning signs for upcoming epidemics, giving us the chance to act and prepare more.