Ovitraps stand out among the tools used to survey mosquitoes that transmit the Zika virus, and other diseases such as dengue and chikungunya. This, due their ease of use and low cost, which enables sustainability and acceptance in communities.
To this end, the Colombian Red Cross Society is currently piloting the use of ovitraps in 5 departments in the country, with participation by 100 families and installation of nearly 200 ovitraps. This initiative is part of the Community Action on Zika (CAZ) project implemented by the International Federation of Red Cross Red Crescent Societies, the Colombian Red Cross (CRC), Save the Children (SC) and with support from the United States Agency for International Development (USAID). Additionally, activities are implemented in coordination with national and local health authorities.
“An ovitrap is basically a 12cm black containers with water and a substance to attract mosquitos. They are used as part of a participatory process with the community, since each family participates by “adopting” the ovitrap in their home and monitors it together with volunteers. This enables us to make sure that community members are the key to controlling mosquito populations.” – said Juan Carlos Alvarez, Vector Control Consultant with the IFRC.
Ovitraps are designed to attract female mosquitos and create the perfect environment for them to lay eggs, creating a mosquito breeding site. Normally, this is a black container, filled with water, a grass solution and two wooden pallets. Then, the container is places in a dark area of the home and reviewed weekly for eggs and larvae. The relative precision of an ovitrap allows to monitor the virus-transmitting vectors.
“Despite the simplicity of this tool, its impact can be amplified by incorporating technology”, noted Alvarez. “As one of the innovative approaches introduced by the project, the Colombian Red Cross, Medellin branch, is implementing geo-location and data management together with its ovitraps.”
The volunteers who installed and monitor ovitraps in the communities of Maria Cano and Bello Oriente took pictures of each of the 20 houses where they installed the 40 ovitraps. Using the photos and location, they were able to input the information into a digital database and geo-map the location of each ovitrap. In follow-up monitoring visits, volunteers include information on the latest sample that they have collected, including a photo of the ovitrap, the sample and record any additional comments. This information is then processed and coded by color to identify higher or lower numbers of eggs in the ovitrap.
The approach combines mobile technology and ovitrap installation and monitoring ton ensure that data collected is readily available and accessible, processed and supports decision-making. The image below, for example, shows color-coded households based on the results of ovitrap monitoring and a photo of the sample collected during the last visit.
“Thanks to these tools we have been able to visualize the way each household and ovitrap behaves over time and the results we are getting. We also have notes on each one, for example if there are pregnant women in the household, any suspected cases of the Zika virus, and other information. This helps us make decisions based on real information as an institution.” – said Juan Quintero, CAZ project coordinator for the Medellin branch.
“We use ovitraps as one of the key components of the community-based surveillance and monitoring strategy within the CAZ project. Not only are they important in monitoring the populations of mosquitos that transmit the Zika virus, we can also get a better understand of what vector control initiatives work best in the given community.” – notes Diany Romo, Epidemiological Surveillance Consultant with the IFRC.
The overall objective in using ovitraps is to significantly reduce the population of Aedes aegypti mosquitoes in the areas of intervention to prevent the transmission of the Zika virus, and other mosquito-borne diseases such as dengue and chikungunya.