Mosquito

Welcome to Denguematters - a dedicated newsletter and website covering the latest information, expert opinion, challenges and issues surrounding dengue - one of the fastest-emerging infections on the planet. More than 3.5 billion people, or over half the world’s population, across 120 countries live under the threat of dengue infection.

Given the scale of this threat, and the human and economic impact of dengue on families, communities and governments, it is remarkable that dengue remains poorly understood. Denguematters newsletter is designed to specifically address this educational need, encourage debate and increase awareness of this costly disease.

 

Issue 16 - Dengue Updates | October 2014

Dengue News form Around the World

In Past Decade, Dengue Cases up Five-Fold in the Americas
 
Despite concerted efforts to control the disease, the number of dengue cases has increased substantially in the Americas over the past decade. For the 10 years ending 2013, the number of dengue cases in the Americas rose five-fold, according to data presented at a recent high-level meeting convened by the Pan American Health Organization/World Health Organization (PAHO/WHO).
 
Experts blamed the increase on uncontrolled urbanization, poor environmental management, and climate change, among other factors.
 
Back in 2003, only 517,617 cases were reported region wide. Between 2009 and 2012, an average of more than 1 million cases were reported annually. The latest data show that 2013 was one of the worst years on record for the region, with some 2.3 million cases.
 
“All government sectors, communities, and families have to work together to fight the (Aedes aegypti mosquito) and control this disease," said Marcos Espinal, Director of the Department of Communicable Diseases and Health Analysis at PAHO/WHO.
 
Brazil was one of the hardest hit countries in the Americas in 2013, with a total of 1.47 million cases reported, according to the PAHO/WHO data, while neighboring country Paraguay contributed more than 144,000 cases to the year's record total. Nearby, Argentina accounted for a little more than 9,000 additional cases.
 
Central America and Mexico, as a region, accounted for nearly half a million cases of dengue in 2013. Mexico alone contributed more than 231,000 cases to that total.
 
Encouragingly, the number of deaths due to dengue has dropped from 0.07% to 0.05% due to better clinical management and implementation of PAHO/WHO guidelines. The improvements in care probably spared at least 1,500 deaths last year alone.
 
 
 
“Countries have made major efforts to prevent deaths from dengue through timely treatment, following the new WHO recommendations,” said Luis Gerardo Castellanos, head of the PAHO/WHO Neglected, Tropical, and Vector-borne Diseases Unit.
 
To call attention to dengue concerns, WHO chose vector-borne diseases as the theme of this year's World Health Day. The campaign included helpful posters, factsheets, videos, and other materials designed to highlight how simple measures can be taken to protect against dengue.
 
 
 
Research News
 
Recent Reports Highlight Growing Concerns Over Dengue "Hyperendemicity"
 
As overcrowded cities provide increasingly ideal conditions for transmission of dengue, researchers fear that hyperendemicity--or the co-circulation of multiple dengue serotypes--will become more established, thus increasing the risk for more severe disease that could affect increasingly younger age groups.
 
In Asian countries, notably India, recurring dengue epidemics have resulted in established hyperendemic areas, often in large and heavily populated cities.
 
Co-circulation of multiple dengue serotypes is emerging in more countries, including Brazil.
 
In 2011, researchers detected simultaneous circulation of all four dengue serotypes in Manaus, a city in the middle of the Amazon rainforest. Now, researchers have evidence that urban outbreaks in 2013 in Sao Paulo, the country's main international center of business, culture, and tourism, were also associated with all four serotypes.
 
 
 
A recent effort to globally map the spread of dengue serotypes over time has confirmed these concerns over hyperendemicity. As seen in the illustration accompanying this article, co-circulation of dengue serotypes has increased substantially over time.
 
 
Cost of Dengue Outbreaks is Considerable, Data Collection Still a Challenge
 
It's assumed that surveillance for dengue, and for Aedes aegypti, the main mosquito vector of dengue, will result in major cost savings, reducing the social and economic impact in countries that can ill afford spending to combat this disease.
 
The impact of such interventions has nevertheless been difficult to quantify. Recent efforts have started to unveil evidence on the cost of dengue outbreaks and the benefit of efforts to curtail them, though researchers say much more work needs to be done.
 
This international team of researchers evaluated the cost of dengue in four countries, and looked at the cost/benefit ratio of vector control interventions.
 
By analyzing 17 key data sources, researchers found the cost of dengue outbreaks in 2011 ranged from a low of US$2.8 million in Dominican Republic; to US$4.5 million in Peru; US$6.75 million in Indonesia; and US$13 million in Vietnam.
 
Encouragingly, the costs of vector control interventions were lower than the costs of the outbreaks avoided, the analysis showed. However, the analysis was challenging and limited by a lack of standardization in how outbreak costs are calculated. Moreover, some reports blurred the lines between the definition of cost of dengue illness and cost of dengue outbreaks.
 
Altogether, these results suggest a need for closer study and greater consistency in methods for calculating the cost of dengue--and also the need for better surveillance, researchers said.
 
In an assessment of the economic value of vaccination, a recent study showed that traditional economic evaluations, especially in the case of dengue, often overlooked a “series of benefits of that have not previously been accounted for.” Those benefits include reduced spending on outbreak control, averted losses in tourism flows, decreased productivity losses and direct foreign investment flows. Including these benefits in economic evaluations significantly strengthens the case for inclusion of dengue vaccination in national immunization programs the researchers noted.

 

Last edited: 01/10/2014