Brazil mu­tant mosquitoes to breed out dis­eases

Males cre­ated to mate and then die

Kuwait Times - - FRONT PAGE -

PIRACICABA: Sci­en­tists in Brazil are pre­par­ing to re­lease mil­lions of fac­tory-bred mosquitoes in an at­tempt to wipe out their dis­tant cousins that carry trop­i­cal dis­eases. The in­sects’ method: have sex and then die. Bri­tish firm Ox­itec says its ge­net­i­cally mod­i­fied mosquitoes will swarm in among or­di­nary species such as Aedes ae­gypti, the in­sect that car­ries feared dis­eases such as Zika, dengue, yel­low fever and chikun­gunya.

They will mate with the fe­males of the or­di­nary mosquitoes, spawn­ing ba­bies with a ge­net­i­cally in­built flaw that causes them to die quickly. With their work done, the mod­i­fied fa­ther mosquitoes will then give up the ghost them­selves-as they are ge­net­i­cally pro­grammed to do. Ox­itec says its fac­tory in the town of Piracicaba, north­west of Sao Paulo, can pro­duce 60 mil­lion mu­tant mosquitoes a week.

Piracicaba is the world’s “first and big­gest fac­tory” of ge­net­i­cally mod­i­fied mos­qui­tos, said Ox­itec pres­i­dent Ha­dyn Parry. “This is the only place where we have a fac­tory like this. We can use this as a hub for Brazil,” said Parry, who trav­eled to Piracicaba for the plant open­ing. Cur­rently their only Brazil­ian cus­tomer is the city of Piracicaba, “but we are hav­ing con­ver­sa­tions with sev­eral municipalities and states,” Parry said.

Mosquitoes by the mil­lions

Ac­cord­ing to the firm, five field tests that they con­ducted be­tween 2011 and 2014 — in Panama and the Cay­man Is­lands, as well as the north­east­ern Brazil­ian state of Bahi­ashowed the pop­u­la­tion of wild Aedes ae­gypti in­sects dropped by 90 per­cent af­ter the mu­tant mosquitoes were re­leased. Ox­itec does not yet have a sales per­mit from Brazil’s An­visa health au­thor­i­ties, and there are no epi­demi­o­log­i­cal stud­ies show­ing whether mosquito-car­ried dis­eases drop af­ter the fac­tory-bred in­sects are re­leased.

Parry is not con­cerned. “We are still wait­ing for An­visa ap­proval-we have no date for it, but we ex­pect it for 2017,” he said. And none of this has stopped the mayor of Piracicaba from sign­ing a four-year, $1.1 mil­lion deal with Ox­itec. In its first wave, the com­pany will re­lease 10 mil­lion fac­tory-bred mos­qui­tos each week into this city of 360,000 peo­ple.

The need for in­sect con­trol is press­ing, as the sum­mer in the south­ern hemi­sphere ap­proaches and the mosquito pop­u­la­tio­nand cases of the dis­eases that they carry-is likely to boom. As of July nearly 1.4 mil­lion cases of dengue were recorded in Brazil, fol­low­ing the record 1.6 mil­lion cases in 2015, ac­cord­ing to health min­istry fig­ures. In the same pe­riod 174,000 cases of Zika were re­ported.

The Zika virus out­break be­gan in late 2015 in Brazil and has since spread across the Americas. Zika is par­tic­u­larly dan­ger­ous to preg­nant women be­cause it can cause birth de­fects such as mi­cro­cephaly, in which ba­bies are born with unusu­ally small heads and brain de­for­mi­ties. Zika in­fec­tion has also been linked to a nerve and im­mune dis­or­der called Guil­lain-Barre syn­drome.

Sex and death

Sci­en­tists keep the spa­cious rooms at the Piracicaba fac­tory at tem­per­a­ture and hu­mid­ity lev­els ideal for mosquito breed­ing. While fe­male mosquitoes are kept for breed­ing, male mosquitoes of the OX513A breed-es­pe­cially de­vel­oped by Ox­itec in 2002 — are re­leased to mate with fe­males in the wild, pro­duce short-lived off­spring, then die.

Ox­itec bi­ol­o­gist Karla Te­pedino dis­misses en­vi­ron­men­tal­ists’ con­cerns about the lack of long-term im­pact stud­ies. “There are three es­sen­tial fac­tors for the trans­mis­sion of these dis­eases: the mosquitoes, the virus and hu­mans. What we do here is elim­i­nate the mosquitoes, which trans­mit the virus,” Te­pedino told AFP. “Elim­i­nat­ing the vec­tor, we elim­i­nate the dis­ease,” she said.

The Aedes ae­gypti mosquito is welladapted to city life as it can breed in even tiny amounts of wa­ter, such as a pud­dle of rain­wa­ter or wa­ter pooled in flow­er­pots. Ex­perts have pointed to poor san­i­ta­tion and the prac­tice of stor­ing open wa­ter con­tain­ers in poor neigh­bor­hoods as con­tribut­ing fac­tors in the ex­plo­sive growth of the mosquito pop­u­la­tion. Sep­a­rately, Rio de Janeiro au­thor­i­ties are at­tempt­ing to con­trol their mosquito pop­u­la­tion by re­leas­ing in­sects in­oc­u­lated with the Wol­bachia bac­te­ria, which makes them re­sis­tant to Zika, dengue and other viruses. —AFP


SAO PAULO: View of lar­vae of mosquito Aedes ae­gypti OX513A, in­fected with the Wol­bachia bac­te­ria which al­ters the re­pro­duc­tive ca­pa­bil­ity of its host at Ox­itec.

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