Health: From ENEA new biotechnological method against tiger mosquito
25/10/2018
ENEA has developed a biotechnological method to limit the reproduction of the tiger mosquito and break down its ability to transmit tropical viruses. This was possible thanks to the introduction in the laboratory mosquito of specific strains of the Wolbachia bacterium, harmless to humans and present in most insects. The females showed a cancellation of the transmission of the Zika virus and a reduction to less than 5% of the Dengue and Chikungunya viruses, while the males were capable of making the wild females of the species sterile after mating, affecting their chance of reproducing.
Tested in controlled conditions against both Italian and tropical tiger mosquito populations, the ENEA biotechnology method aims at preventing the risk of epidemics associated with these viruses and has been tested as part of the European project INFRAVEC 2, thanks to the collaboration with the virology department at the Pasteur Institute in Paris. The results were published in the scientific journal PLoS Neglected Tropical Diseases.
"The tiger mosquito, a species of Asian origin reported for the first time in Italy in 1990, is a vector of several pathogenic viruses for humans and its presence in the Mediterranean regions exposes us to the risk of transmission, as confirmed by the Chikungunya epidemics in Emilia Romagna in 2007, with over 200 cases of human infection, to which only last year another 300 cases were added between Lazio and Calabria ", ENEA researcher Maurizio Calvitti of the Biotechnology and Agroindustry Division pointed out. The Chikungunya disease, which in Swahili means "what curves" or "contorce", manifests itself after an incubation period of 2-12 days, with fever and joint and muscular pains often so debilitating as to limit the movements of patients, headaches, fatigue and rash that may last for a few weeks.
"The method is not based on genetic modifications but on the manipulation of the natural bacterial flora of the reproductive apparatus of insects, using bacterial strains widespread in the environment and absolutely harmless to humans. In practice, through the administration of an antibiotic, the bacterium Wolbachia is removed from the cells of the reproductive tissue of the tiger mosquito and is replaced, by embryo microinjection, by different variants of the same bacterium, taken, in our case, by the common mosquito and the fruit midge, Riccardo Moretti, ENEA researcher, explained.
"The first variant of the Wolbachia bacterium makes males able to sterilize wild females with which they mate, while it’s the second variant that interferes with the transmission of viruses," Moretti added. "The control methods of mosquitoes based on the release of sterile males are an alternative to highly specific and environmentally friendly insecticides, and therefore safely exploitable even in urban centers. An intensive use of pesticides can indeed have a negative impact on the environment and on living organisms as well, in addition to giving rise to phenomena of resistance development by mosquitoes that are difficult to manage ", Elena Lampazzi, member of the same ENEA research team, pointed out. "Thanks to this biotechnological method, the infertility factor is inherited by all the children of a female mosquito who carries it. Moreover, compared to the traditional sterile insect technique based on irradiation with γ ox rays, this bacterium has allowed us to obtain, at lower costs and intervention times, more efficient male specimens in inducing infertility in wild females", Calvitti concluded .
Although not yet used in Europe, the European Agency for Chemical Substances (ECHA) has classified the ENEA method as a biocide - assimilated to substances, mixtures or methods used for the control of harmful organisms - while the Italian Ministry of Health has given the green light to field experimentation on controlled areas.
For more information:
Maurizio Calvitti, maurizio.calvitti@enea.it
Riccardo Moretti, riccardo.moretti@enea.it
Elena Lampazzi, elena.lampazzi@enea.it
Moretti R, Pei-Shi Y, Houé V, Lampazzi E, Desiderio A, Failloux A-B, Calvitti M (2018). Combining Wolbachia-induced sterility and virus protection to fight Aedes albopictus borne viruses. PLoS Neglected Tropical Diseases, in press. 10.1371/journal.pntd.0006626.