‘Toxorhynchites’ mos­quito species vs. malaria, dengue car­ri­ers

Palawan News - - PEACE & ORDER - By Ce­leste Anna For­moso

An ele­phant mos­quito species called “Toxorhynchites,” which is un­der­go­ing en­to­mol­ogy study in a De­part­ment of Health (DOH)-run in­sec­tary in Palawan, may hold promise against life-threat­en­ing mos­quito-borne dis­eases, such as malaria and dengue fever. Also called the “mos­quito eater,” the Toxorhynchites do not con­sume hu­man blood but feed on other mos­quito lar­vae dur­ing their ju­ve­nile form, en­to­mol­o­gist Jessie Bra­ganza Jr. of the Palawan Satel­lite Lab­o­ra­tory, De­part­ment of En­to­mol­ogy, Re­search In­sti­tute for Trop­i­cal Medicine (RITM) of the DOH said on Fri­day. Bra­ganza, who is part of a health team that has been study­ing the Toxorhynchites since 2016, said their lar­vae con­sume those of other mosquitoes, mak­ing it ben­e­fi­cial to hu­mans. He said they have tested feed­ing the Toxorhynchites with Aedes ae­gypti lar­vae, the mos­quito re­spon­si­ble for spread­ing dengue, and the “re­sults have been as­sur­ing so far.” “It’s a Toxorhynchites species. Ac­tu­ally, this mos­quito we are study­ing has over­lap­ping char­ac­ter­is­tics with Toxorhynchites splen­dens or an­other species. We have not tried feed­ing them with Anophe­les mosquitoes that carry malaria,” he added. How­ever, he said this will also be part of their study as they go along in help­ing find a so­lu­tion against mos­quito dis­ease car­ri­ers. “Based sa study namin sa lab­o­ra­tory, to­toong ki­nakain nila ang mga kiti-kiti ng ibang lamok. Ka­pag lumaki na sila ay enough na ang pro­tein sa katawan nila kaya hindi na nila ki­nakain ang mga lar­vae ng iba. Hindi rin sila harm­ful sa hu­mans,” Bra­ganza also said. He noted that they tried rear­ing Anophe­les mos­quito lar­vae in the in­sec­tary to feed to the Toxorhynchites, but they have not been suc­cess­ful since their lar­vae ap­pear to pre­fer the wilds to the lab­o­ra­tory breed­ing set up. “We started test­ing Aedis mosquitoes, es­pe­cially in Puerto Princesa be­cause of the ad­vent of dengue. In Anophe­les mos­quito, we tried but they did not thrive in a lab­o­ra­tory set up,” he said. He added that they re­ally had no plan to study the ele­phant mos­quito species in the past. How­ever, in one of their field as­sign­ments, they were able to col­lect Toxorhynchites. Bra­ganza said they read about Toxorhynchites ref­er­ences in other coun­tries and found out that its lar­vae also feed on other mos­quito lar­vae. “Ang ka­gan­da­han sa lamok na ito, hindi siya nagfe-feed ng blood mula sa tao o sa ibang hayop. Ki­nakain niya ang kapwa niya lar­vae kasi kailan­gan niyang mag-con­sume ng pro­tein papunta ng adult stage (What’s good about this mos­quito is it does not feed on hu­man blood. Its lar­vae feed on other mos­quito lar­vae be­cause they need to con­sume pro­tein),” he said. Each larva of Toxorhynchites can feed on five to 10 lar­vae, ac­cord­ing to their study. Bra­ganza said their next trial will in­volve plac­ing 500 Aedes ae­gypti lar­vae on a tray to see how fast the Toxorhynchites can con­sume them to the adult stage. DOH As­sis­tant Sec­re­tary Maria Fran­cia Laxa­m­ana said if study re­sults are promis­ing, es­pe­cially against the dengue lar­vae, then it might be in­tro­duced later in some ar­eas to fight the life-threat­en­ing dis­ease.

“Itu­loy niyo na ‘yan kasi baka promis­ing nga. Kahit hindi na niya nakakain ang mga lar­vae ka­pag lumaki siya, imag­ine nalang kung la­hat ‘yan ku­main ng mga l ar­vae. Kahit pa­paano makak­abawas pa rin. Da­pat ipag­pat­u­loy niyo ‘yan,” Laxa­m­ana said. DOH 4-B (Mi­maropa) of­fi­cerin-charge, Di­rec­tor Mario Baquilod, an­nounced the en­to­mol­ogy study of the ele­phant mos­quito dur­ing the 8th ASEAN Dengue Day cel­e­bra­tion in the prov­ince last June. He said then that the cur­rent RITM en­to­mo­log­i­cal re­search may have found a large lar­vae-eat­ing mos­quito that has the po­ten­tial of de­stroy­ing the im­ma­ture dengue-car­ry­ing Aedes ae­gypti mosquitoes. (with re­ports from Aira Ge­nesa Mag­dayao/PNA)

(Own work by Acro­cynus/Wikipedia)

En­to­mol­o­gist Jessie Bra­ganza Jr. of the Palawan Satel­lite Lab­o­ra­tory, De­part­ment of En­to­mol­ogy, Re­search In­sti­tute for Trop­i­cal Medicine (RITM) of the DOH, said the ele­phant mos­quito they are study­ing may look like Toxorhynchites specio­sus, Culi­ci­dae, Diptera in this photo to the naked hu­man eye, but not quite. He said they are still ver­i­fy­ing the species of the Toxorhynchites they have in the RITM Palawan in­sec­tar­ium which holds the po­ten­tial to pre­vent the spread of the life-threat­en­ing dengue fever.

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