Malaria linked to go­ril­las

Re­search sug­gests a par­a­site that in­fects hu­mans came from the large pri­mates.

Los Angeles Times - - The Nation - Amina Khan

One of the nas­ti­est of the par­a­sites that cause malaria may have orig­i­nated in go­ril­las, sci­en­tists say af­ter an­a­lyz­ing thou­sands of sam­ples of pri­mate fe­ces. The find­ings may clear chim­panzees of much of the blame.

Pre­vi­ous stud­ies had sug­gested that the malaria par­a­site Plas­mod­ium fal­ci­parum, which in­fects hu­mans, had evolved from a par­a­site that in­fected the com­mon an­ces­tor of hu­mans and chimps be­fore their lin­eages di­verged 5 mil­lion to 7 mil­lion years ago. An­other the­ory posited that hu­mans had con­tracted the par­a­site from chim­panzees — as hap­pened with HIV — pos­si­bly af­ter hunt­ing the pri­mates for their meat.

To test these the­o­ries, re­searchers at the Uni­ver­sity of Alabama at Birm­ing­ham an­a­lyzed ge­netic ma­te­rial in sam­ples of fe­ces from many dif­fer­ent types of pri­mate species: chim­panzees, bono­bos, western go­ril­las and east­ern go­ril­las. Their find­ings were pub­lished on­line Wed­nes­day in the jour­nal Na­ture.

Ex­tract­ing ge­netic in­for­ma­tion from go­ril­las in the wild is not an easy propo­si­tion, said Beatrice Hahn, a mi­cro­bi­ol­o­gist at the uni­ver­sity, who co-wrote the study.

But af­ter stud­ies came out show­ing that ge­netic in­for­ma­tion could be ex­tracted from an­i­mal drop­pings, Hahn and her col­leagues re­al­ized they were in luck: They had close to 3,000 fe­cal sam­ples in stor­age from ear­lier work on the simian im­mun­od­e­fi­ciency virus, the pre­cur­sor to HIV.

The re­searchers de­tected DNA from sev­eral types of

Plas­mod­ium par­a­site in the chim­panzee and western go­rilla sam­ples, but no trace of the malaria-car­ry­ing bug in bonobo or east­ern go­rilla waste.

And the go­rilla sam­ples con­tained a par­a­site nearly iden­ti­cal to Plas­mod­ium fal­ci­parum, the most com­mon and se­vere of hu­man malaria par­a­sites. There­fore, go­ril­las, not chimps, must have passed on the dis­ease, Hahn said.

Know­ing where malaria came from would bring re­searchers closer to un­der­stand­ing which dis­eases can jump be­tween species, why they jump and, per­haps, whether such events might be pre­vented, Hahn added.

In an ac­com­pa­ny­ing com­men­tary in Na­ture, Penn State bi­ol­ogy pro­fes­sor Ed­ward Holmes called the re­sults “strik­ing,” though he added that the ef­fort didn’t help sci­en­tists know when the par­a­site jumped from non­hu­man pri­mates to peo­ple.

Hahn es­ti­mated that such a one-time event might have oc­curred 5,000 to 300,000 years ago.

Austin Hughes, an ex­pert on molec­u­lar evo­lu­tion at the Uni­ver­sity of South Carolina in Columbia, said he was skep­ti­cal of the au­thors’ con­clu­sions. He said there could be a lot more ge­netic di­ver­sity in the par­a­sites in­fect­ing hu­mans in Africa than sci­en­tists know of, and thus it was too early to say where Plas­mod­ium fal­ci­paru­mo­rig­i­nated.

Hughes added that he was wor­ried that pin­point­ing go­ril­las as the source of malaria would not en­dear the an­i­mals to lo­cal peo­ple, some of whom kill them for meat.

“There re­ally are se­ri­ous con­ser­va­tion is­sues,” he said.

Ann Bat­dorf

WESTERN GO­RILLA: A DNA study found a bug nearly iden­ti­cal to Plas­mod­ium fal­ci­parum, the most se­vere of hu­man malaria par­a­sites, in go­rilla fe­ces.

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.