Scientists Study Intensified Vector Control Measures to Combat Zika, Dengue and Chikungunya

A community health officer visits a house to educate the owner and check water storage to control mosquito breeding sites, Colombia. Courtesy of PAHO/WHO, J Dempster

Control of mosquitoes that transmit Zika, dengue and chikungunya viruses must be ramped up in the Americas, experts have urged after a three-day meeting at the Pan American Health Organization/World Health Organization (PAHO/WHO).

The new Technical Advisory Group on Public Health Entomology is looking at ways to strengthen vector control programs in the countries, including specific measures for Aedes aegypti, the mosquito that transmits Zika, dengue, chikungunya and yellow fever in the Americas. The group ended its first meeting today after reviewing a series of measures focusing on integrated vector management measures, which include various tools and strategies to cut the toll of vector-borne disease.

The group is chaired by Dr. Karen Polson of the Caribbean Public Health Agency, and includes experts in entomology, vector control, neglected diseases, epidemiology, insecticide resistance management and related fields. It advises PAHO's director, Dr. Carissa F. Etienne, on ways to strengthen surveillance, control and elimination of vector-borne diseases.

"Vector control is the best way we have of combating these diseases," Polson said. "Entomology and vector control works, if used and applied correctly by countries."

Dr. Raman Velayudhan, a vector control expert at WHO noted "We have two Aedes mosquitoes that transmit four diseases, and we don't have much in the way of weapons against them. Dengue, chikungunya, yellow fever and now Zika are growing problems." He added that challenges in Aedes control include the mosquito's adaptation, human movement, surveillance, resistance to pesticides, and its resilience.

Autochthonous, or local, Zika virus transmission has been reported in 31 countries and territories of the Americas, noted Dr. Sylvain Aldighieri, PAHO's Epidemic Alert and Response chief. So far, increases in microcephaly cases and other neonatal malformations have only been reported in Brazil and French Polynesia, although two cases linked to a stay in Brazil were detected in two other countries.

"Our most important tool to combat Zika-and at the same time, dengue and chikungunya-is control of the Aedes aegypti mosquitoes that transmit these diseases. Since these mosquitoes live in and around houses, this will take a concerted effort with intensified community engagement to reduce the number of mosquitoes in the Americas. We are also looking urgently at improving control methods including insecticides and other new technologies," said Dr. Luis Castellanos, chief of Neglected, Tropical and Vector-borne Diseases at PAHO.

The Technical Advisory Group's recommendations are being compiled for PAHO leadership, and they will be used next week at the global Vector Control Advisory Group meeting in Geneva to consider emergency response and vector control tools for Zika virus disease.

Source: PAHO