Re­searchers ex­plore new way of killing malaria in the liver

Kuwait Times - - Front Page -

WASH­ING­TON: In the on­go­ing hunt for more ef­fec­tive weapons against malaria, in­ter­na­tional re­searchers said Thurs­day they are ex­plor­ing a path­way that has un­til now been lit­tle stud­ied - killing par­a­sites in the liver, be­fore the ill­ness emerges. “It’s very dif­fi­cult to work on the liver stage,” said El­iz­a­beth Winzeler, pro­fes­sor of phar­ma­col­ogy and drug dis­cov­ery at Univer­sity of Cal­i­for­nia San Diego School of Medicine. “We have tra­di­tion­ally looked for medicines that will cure malaria,” she told AFP.

For the lat­est research, pub­lished in the jour­nal Science, sci­en­tists dis­sected hun­dreds of thou­sands of mosquitoes to re­move par­a­sites in­side them. Each par­a­site was then iso­lated in a tube and treated with a dif­fer­ent chem­i­cal com­pound - 500,000 ex­per­i­ments in all. Re­searchers found that cer­tain mol­e­cules were able to kill the par­a­sites. Af­ter around six years of work, 631 can­di­date mol­e­cules for a “chem­i­cal vac­cine” have been iden­ti­fied - a nor­mal vac­cine that would al­low the body to make an­ti­bod­ies.

“If you could find a drug that you give on one day at one time that will kill all the malaria par­a­sites in the per­son, both in the liver and in the blood­stream, and last for three to six months. Yeah, that’d be su­per but there is no drug like that right now,” said Larry Slutsker, the leader of PATH’s Malaria and Ne­glected Trop­i­cal Dis­eases (NTDs) pro­grams.

Re­duc­ing the num­ber of doses is cru­cial. That’s be­cause many med­i­ca­tions avail­able to­day must be taken over three days, said David Reddy, CEO of Medicines for Malaria Ven­tures. But of­ten, af­ter the first dose, a child be­gins to feel bet­ter and the fever lessens. Par­ents then keep the other two doses in case an­other of their chil­dren falls ill. “That has two im­pacts. First the child does not get cured prop­erly and se­condly it builds drug re­sis­tance,” Reddy said.

Malaria is caused by a minis­cule par­a­site, called Plas­mod­ium. Fe­male mosquitoes trans­mit the par­a­site when they bite peo­ple for a meal of blood (males do not bite). Then, the par­a­site lodges in the liver and mul­ti­plies. Af­ter a cou­ple of weeks, the pop­u­la­tion ex­plodes and par­a­sites run ram­pant in the blood. At this stage, fever, headache and mus­cle pain be­gins, fol­lowed by cold sweats and shiv­er­ing. Without treat­ment, ane­mia, breath­ing dif­fi­cul­ties and even death can fol­low, in the case of Plas­mod­ium fal­ci­parum, which is dom­i­nant in Africa.

The research pub­lished Thurs­day of­fers a “promis­ing path, as long as it last sev­eral months,” said Jean Gau­dart, pro­fes­sor of pub­lic health at the Univer­sity of AixMar­seille. Gau­dart said new ap­proaches are nec­es­sary be­cause re­sis­tance is on the rise in Asia against the most ef­fec­tive treat­ment us­ing artemisinin, de­rived from a Chi­nese plant. “We re­ally need new com­pounds,” he said. Now it’s up to re­searchers to con­firm which of the 631 mol­e­cules iden­ti­fied have a real shot at wip­ing out this global scourge.

The World Health Or­ga­ni­za­tion said last month that global ef­forts to fight malaria have hit a plateau, with two mil­lion more cases of the killer dis­ease in 2017 - 219 mil­lion - than the pre­vi­ous year. Malaria killed 435,000 peo­ple last year, the ma­jor­ity of them chil­dren un­der five in Africa. The first malaria vac­cine for chil­dren - called RTS,S - will be dis­trib­uted in thee African coun­tries in 2019, though it only re­duces the risk of malaria by 40 per­cent af­ter four doses. De­spite bil­lions of dol­lars spent, the world still has not found a real ef­fec­tive so­lu­tion to malaria. — AFP

OBUASI, Ghana: In this file photo taken on May 1, 2018, a worker shows some of the mos­qui­tos they breed at the En­to­mol­o­gist Research Cen­tre. —AFP

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