JEDDAH, 3 March 2003 — The discovery of seven cases of dengue fever (DHF) here has raised concern among the general public. They are complaining that they are not being provided enough information about the disease, which was an epidemic in the Kingdom in 1994.

“Four of the seven cases of dengue fever in Jeddah were treated at the Al-Fakeeh Hospital, and all of the individuals have fully recovered,” Dr. Ali Zaki of the virology laboratory at Al-Fakeeh Hospital in Jeddah told Arab News yesterday.

The seven cases of dengue were reported last week by Arab News. The outbreak of the potentially deadly virus was of particular concern because it could not be explained away with reference to diseases which periodically break out during the annual Haj season. None of the victims had performed Haj this year. Dr. Zaki isolated the dengue virus in 1994, and also has among his credits being the first person to discover the Alkhorma strain of the virus.

He told Arab News that dengue could be distinguished from flu in a number of ways.

“Influenza is highly contagious and can easily be passed to others, but dengue is not like this. It has to be caught directly from mosquitoes. The symptoms of dengue are severe rashes, but unlike influenza it doesn’t affect the respiratory system severely.”

Dengue viruses are transmitted to humans if they are bitten by an infected female Aedes mosquito. Mosquitoes generally acquire the virus while feeding on the blood of an infected person. The risk of infection is greater in urban areas which encourage mosquito breeding, for example where household water storage is common or where solid waste disposal services are inadequate. The disease often affects workers sleeping near stagnant water.

People living in the Faisaliya and Bawadi districts of Jeddah are apparently most at risk at present, since the districts are the main centers of infected mosquito activity. But conditions in the city generally are ripe for the disease to spread.

Jeddah is full of pools of stagnant water, overflowing septic tanks, a rising water table coming up through holes in pavements and on waste ground, leaking sewage tankers, leaking water pipes, and inadequate if not non-existent drainage.

“Today it is much easier to detect dengue in the Kingdom than it was in 1994 because we now have a ready-made kit especially designed for that purpose, and if patients come to us within four days of being infected they recover much faster,” Dr. Zaki said.

The Alkhorma strain of the virus was detected by Dr. Zaki in 1994 and named after the Saudi town of Alkhorma.

“The Alkhorma virus (ALKV) is a tick-borne flavivirus responsible for hemorrhagic fever in humans. The first symptoms include vomiting, epigastric pain, diarrhea, and hematemesis for more than four days. The patient also suffers from an elevated liver enzyme,” Dr. Zaki told Arab News.

Dr. Zaki explained that all the Alkhorma patients had a history of direct contact with animals and meat.

“The main difference between dengue and the Alkhorma strain is that dengue is spread by mosquitoes while Alkhorma can be caught through direct contact with animals and fresh meat, and is spread only by ticks. The first six patients were actually butchers.”

The fatality rate of the Alkhorma virus is much higher than that of dengue — two of the 16 cases so far discovered have been fatal, compared with only one in every 1,000 for dengue.

Trial vaccines are now being tested, Zaki said, “but it is not 100 percent curable. The only solution is to control the mosquitoes and avoid direct contact with animals.”

And that is where Jeddah Municipality should bring its authority to bear.