Cyprus this month released the first batch of 100,000 sterile mosquitos to begin the implementation of a Food and Agriculture Organization (FAO) and International Atomic Energy Agency (IAEA) project testing the use of a nuclear technique to eradicate an invasive species of mosquitoes found in the country.
Cyprus confirmed the presence of the Aedes aegypti mosquito, also called Yellow Fever mosquito, on the island in 2022. This species of mosquito can carry serious vector-borne diseases such as chikungunya, dengue, yellow fever and Zika. The Aedes albopictus - also a carrier for such diseases - was also confirmed to be present on the island in 2022. Vector-borne diseases cause over 700,000 global deaths per year and the presence of the two species poses an immediate threat to Cyprus' economy and healthcare system in case of a disease outbreak.
The Sterile Insect Technique (SIT) has been identified as a possible method to eradicate this invasive species in Cyprus. The country released the first weekly batch of 100,000 mosquitoes on 13 June, and two more batches have been released since then. Each week until the end of the year, batches of 100,000 mosquitoes will be released in Cyprus as part of the pilot project, which is being conducted within the framework of the IAEA's technical cooperation programme.
"The presence of the two species of invasive mosquitoes introduced significant challenges to Cyprus and, if Aedes aegypti is not eradicated, could have serious consequences for all of Europe," said IAEA Director General Rafael Mariano Grossi. "The SIT pilot project offers a nuclear solution, and its success would have far reaching benefits for Cyprus and worldwide."
The SIT is a form of insect birth control using irradiation. The environment-friendly insect pest management method involves rearing large quantities of male mosquitoes, sterilizing them by irradiation and then releasing them to mate with wild females. As the females consequently don't produce any offspring, the insect population declines over time up to its eradication. The method has been used for decades to manage agricultural pests such as the Mediterranean fruit fly, the false codling moth, the New World screwworm, and tsetse flies.
The pilot trial aims at demonstrating the feasibility of using SIT against mosquitoes. The SIT is still being tested against mosquitoes, but successful pilot trials resulted in an almost 100% reduction of Aedes aegypti in Cuba in 2020 and Aedes albopictus in China in 2017. The pilot project in Cyprus is the first time SIT is used against Aedes aegypti in Europe. The SIT has been used against Aedes albopictus since the 2000s in Italy and is also currently used in other European countries.
"We are aware of the threat represented by these invasive mosquito species, especially Aedes aegypti, and we are deploying considerable efforts to prevent their spread," said Dr Popi Kanari, Minister of Health of Cyprus.
Though the date of entry is not yet known, experts have determined that the area colonized by the mosquito population is still limited and can be eliminated by SIT. The Ministry of Health in Cyprus has been implementing complementary mosquito control, including larvae habitat removal, treatment of the public drainage system and targeted insecticide spraying in authorized areas. These methods are not sufficient to eradicate the Aedes aegypti species alone.
"We are very concerned about the fact that the two species can carry serious vector-borne diseases such as Yellow fever, dengue, Zika and chikungunya and thus we have alerted our hospitals and labs", said the Director of Cyprus's Medical and Public Health Services Dr. Elisavet Konstantinou.
"We have informed the public about the actions we are taking to eradicate the pest. We are going door-to-door to educate and inform the public about the measures they can be taken to reduce potential mosquito hatching grounds in order to prevent Aedes aegypti and Aedes albopictus from multiplying," added Herodotos Herodotou, Head of the Environmental Health Services of the Medical and Public Health Services of the Cyprus Ministry of Health.
In parallel, over the past six months, scientists working for the Insect Pest Control Laboratory of the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture in Seibersdorf, Austria, have mass-reared the local invasive strain of Aedes aegypti from Cyprus to produce thousands of sterile males.
The first of the weekly batches of 100,000 sterile males were shipped from the Insect Pest Control Laboratory to Cyprus - a country of roughly 1.2 million people - and were released with the support of Jérémy Bouyer, a Medical Entomologist at the Joint FAO/IAEA Centre.
Each batch of insects will be released from specially designed boxes weekly in a test area roughly 0.5 km2 in Kiti, a village near Larnaca international airport, about 50 kilometres south of the capital Nicosia. "In this pilot trial, we want to prove for the first time that SIT can be used to eradicate a mosquito population," said Bouyer. "The collaboration with the Ministry of Health and the Cyprus University of Technology has been instrumental to prepare this landmark trial."
Background
Cyprus University of Technology requested the IAEA's assistance in 2021 to develop a national rapid response strategy for the prevention of the establishment of the Aedes albopictus mosquito on the island.
During an IAEA mission to Cyprus under this assistance programme, experts found the presence of the more dangerous Aedes aegypti mosquito. Upon receipt of the IAEA's emergency response plan, Cyprus informed the IAEA that the Aedes albopictus species had also been detected. Following two more expert missions in October 2022, a report providing recommendations on delimitation has been submitted to Cyprus, followed by the submission of a contingency plan in December.
