The Americas seek to expand genomic surveillance for dengue, chikungunya and other mosquito-borne viruses


Santo Domingo, 16 August 2023 (PAHO)- Laboratory experts gathered this week in Santo Domingo, Dominican Republic, to discuss increasing the use of tools to detect and monitor mosquito-borne diseases in the Americas. The meeting, led by the Pan American Health Organization (PAHO), comes as some countries in region face large-scale outbreaks of dengue and intense circulation of chikungunya.

The annual meeting of the Arbovirus Diagnosis Laboratory Network of the Americas (RELDA), of which PAHO is the technical secretariat, takes place this week until Thursday. Members, which are made up of 35 national laboratories from across the region, technical advisors and WHO collaborating centers, will review ways to expand genomic and entomovirological surveillance to major arboviruses.

"At least nine arboviruses with public health impact - such as dengue, zika, chikungunya and yellow fever - are circulating in Latin America and the Caribbean, so strengthening and expanding laboratory detection and surveillance capacities are key to ensuring a timely response to outbreaks and epidemics," Sylvain Aldighieri, Deputy Director of PAHO's Department of Health Emergencies, said.

Expertos en laboratorio reunidos por la Organización Panamericana de la Salud (OPS) en Santo Domingo, República Dominicana, analizan expandir las herramientas para detectar y vigilar las enfermedades transmitidas por mosquitos en las Américas

Arboviruses are transmitted by the bite of arthropods (mosquitoes and ticks, among others). From the beginning of 2023 until the end of July, more than 3 million new dengue infections and more than 324,000 cases of chikungunya were reported in the Americas. With 27,000 cases across the region in the same period, Zika has a lower incidence rate, while sporadic cases of yellow fever represent a permanent risk of re-emergence of this potentially lethal disease. 

"The epidemiological picture of arboviruses in the region is highly complex due to the epidemic potential of these diseases," José Luis San Martín, PAHO regional advisor on arboviral diseases, warned. "We must carry out an integrated prevention and control strategy that uses new innovations to closely monitor these viruses in laboratories," he added.

During the COVID-19 pandemic, genomic surveillance of SARS-CoV-2 proved key to understanding the virus, its variants, and advising public policy to prevent and control of the disease.

In the past years, investment and international cooperation have strengthened RELDA laboratories, and now at least eight countries in the region have introduced genomic sequencing within the framework of PAHO's Regional Strategy for Genomic Surveillance.

Many countries are taking advantage of these capacities and have started sequencing dengue, yellow fever, chikungunya and other viruses, some for the first time. With RELDA's support, laboratories can expand this surveillance to find out the genomes of arboviruses circulating in their territory, their dispersion patterns and analyze whether mutations are associated with greater transmissibility or severity.

For María Alejandra Morales, director of the PAHO/WHO Collaborating Centre on Viral Hemorrhagic Fevers and Arboviruses, National Institute of Human Viral Diseases (INEVH) in Argentina, "RELDA has a key role to play in the strengthening, growth and continuous improvement of the laboratory component as part of an integrated management strategy for arboviruses."

Morales, who is currently the RELDA coordinator, also believes the expanded work of the laboratories with virological, serological and molecular tests "will make it possible to generate timely and quality information for decision-making that can contribute to the prevention and control of arboviruses."

During the meeting, experts also discussed the status of entomovirological surveillance in the region, i.e. the detection of viruses in mosquitoes before they reach humans. This type of surveillance, already conducted in some countries, can serve as an early warning system to anticipate arbovirus outbreaks or epidemics and allow for a more timely response.

PAHO began promoting entomovirological surveillance in 2017 and created the Entomo-Virological Laboratory Network (RELEVA), which currently includes laboratories in 14 countries. At the meeting, guidelines for this surveillance were presented and discussed. Laboratories in the network are also working on a plan for their implementation and plan to create a comprehensive arbovirus surveillance platform that includes mosquito surveillance data.

RELDA, which celebrates its 15th anniversary this year, is composed of 40 laboratories, technical advisors and WHO collaborating centers, and is the operational arm of the laboratory component of PAHO's Integrated Management Strategy for Arboviral Disease Prevention and Control (known as IMS-arbovirus). Its main objective is to ensure efficient laboratory surveillance and a robust installed capacity to respond to arbovirus outbreaks and epidemics.