Global dengue fever cases surge, with rising numbers in Middle East

Disease found across the region in patients with no history of travel to countries with a tropical climate

Dengue fever is a tropical, waterborne disease spread by mosquitoes. EPA

Global cases of the debilitating tropical disease dengue fever are rising dramatically, with a number of Arab nations seeing a reported rise in cases in recent months.

Dengue fever is a waterborne disease spread by mosquitoes, and is rarely reported in the Emirates.

Cases internationally are increasing, with more than 4.2 million infections reported worldwide in 2023, compared with only 500,000 at the turn of the century. According to the University of Washington's Institute of Health Metrics and Evaluation, the Mena region registered an 88 per cent increase in cases of dengue fever from 1990 to 2019.

The institute also said there had been 1.2 million more incidents of the virus in the World Health Organisation's Eastern Mediterranean Region reported in that time.

Medics in Dubai said although numbers of infected patients requiring care were low, several cases had been reported to health authorities in recent months.

“In 2023, we saw an increased surge in vector-borne disease,” said Dr Nandkishore Mariswamy, an internal medicine specialist at NMC hospital in Dubai Investments Park.

“At the end of the summer, we saw multiple cases of local spread of dengue in Dubai, which was very surprising.”

Dengue fever is usually spread by the Aedes aegypti mosquito, often referred to as the yellow fever mosquito, an unheard of phenomenon in Dubai, Dr Mariswamy said.

“Usually, whenever there is a weather change or climate change, we find that warmer climates favour these vector-borne mosquitoes to thrive,” he said.

Steady rise in cases

According to the WHO, dengue and severe dengue epidemics were first reported in the Eastern Mediterranean region in 1998, and have continued to rise since then. Nine countries in the area, Egypt, Oman, Saudi Arabia, Somalia, Sudan, Yemen, Pakistan, Afghanistan and Djibouti have had outbreaks, with Pakistan, Saudi Arabia and Oman reporting the highest number of confirmed cases in 2023.

The government's Emirates Health Services website has not published any recent data, the site does have a page dedicated to dengue fever, with related information and preventive measures.

It is not just in the UAE where unusual numbers of cases have been reported.

An outbreak of Dengue fever was reported last summer in Egypt, particularly in the Red Sea governorate.

Research by the department of biology sciences at the King Abdulaziz University, Jeddah, Saudi Arabia, found numbers of dengue cases soared in 2023.

Data showed a major epidemic year in the kingdom for dengue, with infections reaching 4,099 in the first half of 2023, a significant increase on previous years.

Only 300 cases were reported in Jeddah in 1994, when disease surveillance was first established.

Common symptoms

Infection in human beings is caused by any one of four closely related dengue viruses that lead to a range of symptoms.

While vaccine research is continuing, the four subtypes of the virus make it a challenge to develop an effective prophylactic.

The most common signs are a high fever of 39ºC to 40ºC, severe headaches, joint and muscle pain, nausea, vomiting, mild nosebleeds and a skin rash.

Symptoms can be mild and almost unnoticeable but in more severe cases, such as in pregnant women, the young and elderly, or those with existing health problems, the symptoms can be fatal if left untreated.

In 2019, the WHO warned that an increase in global outbreaks was likely, particularly during seasonal changes and periods of heavy rainfall.

“With waterborne diseases, most of the time it causes abdominal symptoms like diarrhoea, vomiting and severe dehydration,” said Dr Ali Ahmed from the Canadian Specialist Hospital in Dubai.

“If someone is affected by the disease or their immune system gets activated, they are in a compromised situation,” Dr Ahmed said.

“When a patient comes with symptoms like high fever, we check for dengue as it usually presents with a very high temperature of 39ºC or 40ºC.”

To confirm a diagnosis, doctors will check a patient’s platelets – cell fragments in the blood that prevent heavy bleeding – because a low count could signal internal bleeding, another common symptom.

An antigen blood test would follow to confirm the presence of the pathogen, before the case is reported to health authorities.

Dr Ali said he had recorded about 25 cases of dengue fever in his hospital in 2023, having typically reported about five cases annually in previous years.

Those testing positive for the virus had no history of travel, suggesting it was contracted in the UAE.

“There have been more cases here than in previous years, and I’ve had that confirmed in discussion with other doctors,” he said.

“We are seeing dengue cases arising every year whereas before we didn't see any.”

Many of the recently reported cases appear to be in Dubai, where people who have contracted dengue from mosquitoes have been warning others on social media to be on their guard.

In October, Al Zahra Hospital in Dubai published the details of a 58-year-old woman who had the disease, with no history of travel outside the UAE.

“We have been seeing dengue fever every now and then, with most of the cases we are seeing coming from endemic countries,” said Dr Dima Ibrahim, an infectious disease specialist at Burjeel Medical City in Abu Dhabi.

“It was almost unheard of to have this disease in the Middle East and North Africa because of the dry air. Some colleagues have described cases to have occurred without any history of travel, like in Dubai.”

Once doctors at BMC suspect dengue fever based on symptoms and laboratory testing, cases are reported to the Department of Health.

Hospitals offer supportive treatment, such as medication to treat headaches and to control the fever.

“There is no specific treatment that we give for dengue,” said Dr Ibrahim.

“The weather change has made the presence of mosquitoes more prevalent, so we must try to prevent transmission of the disease.

“If there is an area with mosquitoes, apply insect repellent to the skin and, sometimes, to the bedding. If you have activity outdoors, people should wear long sleeves to protect the skin from mosquito bites.”

It is not just in the UAE where unusual numbers of cases have been reported.

European cases

As of November, 122 cases had been reported in southern Europe in 2023.

According to the European Centre for Disease Prevention and Control, there were 76 confirmed cases in Italy, 43 in France and three in Spain.

The WHO said it was alarmed by the high number of cases in the second half of 2023, with cumulative cases for the year surpassing all previous yearly totals.

In some countries, cases extended beyond historically affected areas of transmission.

In the US, the Centres for Disease Control and Prevention investigated four cases of locally acquired malaria in Texas and Florida.

Mosquito surveillance and control measures were put in place in the affected areas as a result.

As the planet warms, infectious diseases could undergo a dramatic shift, experts said.

More frequent droughts and floods expose populations to more waterborne microbes, while migrating animals interact with species not encountered before, allowing pathogens to spread among new hosts.

Infectious disease specialists in the US called on doctors to update their education and training to adapt to new pathogens and viruses related to climate change.

Viruses, bacteria, fungi and parasites can all cause infectious diseases, many of which are transmitted between humans, or from animals.

Longer summers and shorter, warmer winters around the world with more rainfall and standing water, in which mosquitoes multiply, are driving up vector-borne diseases.

“Clinicians need to be ready to deal with the changes in the infectious disease landscape,” said Prof George Thompson from the department of medical microbiology and immunology at the University of California's Davis School of Medicine.

“Learning about the connection between climate change and disease behaviour can help guide diagnoses, treatment and prevention of infectious diseases.

“I think with improvements in our understanding of the disease, there will be more testing and we'll miss fewer cases that way.”