Ashwaq Alnazawi (Liverpool School of Tropical Medicine): dengue in Saudi Arabia
Ashwaq Alnazawi is a PhD student from Saudi Arabia, currently undertaking research within the Vector Biology Department at the Liverpool School of Tropical Medicine. In this Infectious Thoughts interview, Ashwaq discusses the current dengue threat in Saudi Arabia, the Ministry of Health's strategies to tackle this and the important role which Saudi Arabia can play globally in transmitting important public health messages to the millions of international visitors it receives each year.
The mosquito vectors responsible for carrying dengue are known to be present in Saudi Arabia. There have been outbreaks identified in 1994 (in Jeddah, DENV1, 2 and 3) and then in 1997, 2005 and 2006, and also an outbreak in the Holy City of Makkah 2004 (DENV2 and 3). What in your opinion were the conditions in Jeddah and Makkah that allowed the vector to take hold and the infection to spread? Are there cryptic or unusual breeding sites?
Aedes aegypti is the main vector of dengue in Saudi Arabia, particularly in Jeddah, Makkah and Jazan. The weather in these cities is hot and humid. These conditions are ideal for rapid breeding of mosquitoes and the humid heat also enhances the mosquito’s vectoral capacity to most arboviruses (enhanced ability of the virus to develop inside the insect and become transmitted). Aedes aegypti is a container breeder, which makes it well suited to breed in urban regions where trash, drainage systems, construction sites, animal watering points, condensed water in air conditioners, ant traps on bee hive stands and water storage containers are readily available.
Other than the abundant breeding conditions and breeding sites, these
three cities receive multiple tourist throughout the year, which puts them at higher risk for imported arboviruses cases. Travellers carrying the dengue virus in their blood pose a threat as if they are bitten by Aedes mosquitoes, the virus can quickly spread and cause periodic outbreaks.
What is being done about these sites in terms of vector surveillance and control measures?
The Ministry of Health (MoH) and the municipality have a robust vector control program that incorporates periodic control of breeding sites and indoor residual spraying to control adults. They also conduct intensive fogging campaigns and larval control during outbreaks to prevent further spread of dengue. The MoH sponsors awareness programmes such as public education on dengue disease, symptoms, transmission routes and ways of controlling the disease. The education is wisely offered in mosques, schools, malls and other public gathering places.
Following the 2006 outbreak, the Saudi Preventive Department in the Ministry Health launched a comprehensive plan to control the disease; given the rise in rapid urbanization, international trade and travel to the kingdom what changes to this programme should now be made to reflect these rises?
Saudi Preventive Department in the Ministry Health along with the Ministry of Municipal Affairs have been performing a tremendous job in vector control. However, apart from MoH and the Municipality, citizens regularly hire services from private companies who may not strictly follow control guidelines set by the WHO. It is also not clear if the companies employ trained entomologists and thus the control may not be of the recommended standards. This could be the reason, despite the intense vector control, why Aedes aegypti still persists in high densities in the Kingdom of Saudi Arabia. I recommend the Ministry of Health to develop its current efforts by establishing a vector control department with competent vector biologists to conduct vector control (including surveillance) or to work closely with the private contractors to ensure they follow the control guidelines provided by WHO. The MoH should also ensure that the private companies have trained vector biologists on staff before they are issued with licenses to offer services to private members of Kingdom. The department of vector biology should be tasked to carry out periodic surveillance to assess the effectiveness of the current control methods and make decisions on future control based on the evidence from the surveillance activities. This is important since recent studies have reported that mosquito populations in Makkah and Jeddah are highly resistant to most classes of insecticides currently being used for control. This is crucial because it is inevitable that mosquito control will fail if nothing is done to address the rising levels of insecticide resistance.
I recommend that the MoH and the Municipality establish new regulations to ensure all buildings under construction do not serve as breeding sites for mosquitoes. The regulation could enforce proper disposal of waste, drainage of stagnant water and ensuring water containers are closed or are periodically treated with larvicides. The MoH, in conjunction with the immigration office, should also create a policy to screen visitors travelling from arbovirus endemic regions for symptoms of active infections to reduces cases of imported dengue.
Furthermore, the MoH should encourage companies that hire foreigners to provide services in the Kingdom to educate all their staff about dengue. It is important to teach everyone how to avoid creating breeding sites for Aedes at their work places and why dengue control measures are so important.
The Kingdom of Saudi Arabia is host to very large, international and diverse communities for religious pilgrimages which are the annual Hajj and the year-long Umra. Is there a potential role for the Saudi MoH to engage with these communities who have traveled from all parts of the world to increase awareness of dengue and also take important public health messages home with them? If so what would that role encompass?
As I mentioned earlier, the high number of tourist that visits the Kingdom each year pose an increased risk of disease outbreaks resulting from imported infectious diseases. Consequently, the MOH should continue to support reporting of all cases of infections within the Kingdom, particularly those associated with fever symptoms. MoH should also encourage the locals and visitors to report breeding sites and regions with increased mosquito densities.
In terms of increasing dengue awareness, the ministry should expand their education portfolio to target tourists and locals using flyers and through other information channels (like TV and radio) on the importance of dengue control in several languages because many people living and travelling in the Kingdom of Saudi Arabia do not speak or understand Arabic. Some key messages to stress are: 1. remove breeding sites (empty water containers at night), 2. report people sick with fever, 3. wear personal protection, including repellents, during visits and 4. report areas of high mosquito abundance which will help the vector control team prioritise high risk areas.
How could having a World Dengue Day benefit the Saudi effort against dengue?
The world dengue day is a form of publicity to make people aware of this disease. It is an excellent way to inform the world that dengue causes significant morbidity and mortality. Such a day helps to sensitise the government and other stakeholders in Saudi Arabia to increase awareness and funding towards dengue control and research. As a form of awareness, on this day, the diverse communities living in the Kingdom of Saudi Arabia will be educated on the importance of controlling Aedes. Community participation is vital for disease control and understanding the best ways to control vector-borne diseases can accelerate the Kingdom’s goal of disease elimination by 2030.