The first comprehensive genomic analysis of the dengue virus has revealed that the disease has become endemic and diverse in China and may survive the year-round in southern parts of the country.
The study provides evidence that China may be at increased risk for more frequent and severe dengue fever outbreaks similar to the 2014 outbreak in Guangdong Province that sickened more than 40,000 people.
"We now have compelling evidence that dengue can persist in China - in some cases up to six to eight years," said Rubing Chen, evolutionary virologist at University of Texas Medical Branch- Galveston.
"We found a surprisingly complex and diverse mix of viral subtypes represented in China, a factor that can mean greater risk of epidemic dengue in the future," he added.
Several recent studies suggested that dengue remains an imported disease in China but these studies used small datasets.
The new research provides one of the most extensive analyses to date, according to Chen, and could be a critical tool in adjusting dengue prevention and control efforts to protect millions of people in China.
Chen and her colleague Guan-Zhu Han evaluated all dengue virus sequences from China available in the public database GenBank.
The team found 50 individual variants and multiple variants during the 2014 Guangdong outbreak.
"Even within the same year, a person can catch dengue more than once if distantly related variants are circulating in the same region," Chen noted.
Regardless of the exact transmission pattern, the authors say that China is facing a substantial dengue threat, with potential invasion into broader areas of the country.
Sporadic cases have been identified in several provinces in recent years.
"The combination of a hot, humid climate ideal for breeding mosquitoes and large population centers in southern China combine to make this area a particular concern for public health officials," the authors pointed out.
The research appeared in the Journal of Tropical Medicine and Hygiene.
