The deadly virus had long con­fined it­self to the back­woods of Africa. In­creas­ing de­for­esta­tion has led to its fre­quent emer­gence as epi­demics


With more than 1,200 deaths in four West African coun­tries, this is the big­gest out­break of Ebola ever

EBOLA IS back, and this time it has held the world hostage. With 2,200 peo­ple suf­fer­ing from the haem­or­rhagic fever and more than 1,200 deaths in four West African coun­tries, as of Au­gust 20, this is the big­gest out­break of Ebola ever recorded. The World Health Or­ga­ni­za­tion has de­clared the epi­demic an “in­ter­na­tional emer­gency” and called for “ex­tra­or­di­nary mea­sures”to con­tain it.

In the ab­sence of any proven cure, the who on Au­gust 12 au­tho­rised the use of ex­per­i­men­tal drugs to fight Ebolavirus. “In the spe­cial cir­cum­stances of this Ebola out­break it is eth­i­cal to of­fer un­reg­is­tered in­ter­ven­tions as po­ten­tial treat­ments or preven­tion,” who as­sis­tant di­rec­tor gen­eral Marie-Paule Kieny said in Geneva, fol­low­ing a meet­ing of med­i­cal ex­perts. The UN health body also called on mem­ber states and donor agen­cies to boost fund­ing and ef­forts to bat­tle the virus.The rea­son for such des­per­ate mea­sure is that lit­tle is known about the virus, though it was dis­cov­ered way back in 1976.

The few sci­en­tists who have tried to un­der­stand the virus say the present out­break in Liberia, Nige­ria, Sierra Leone and Guinea seems to have been caused by the dead­li­est of the five strains iden­ti­fied so far. Known as Zaire, the strain can kill nine of the 10 peo­ple it in­fects within a week of the ap­pear­ance of symp­toms. Another strik­ing as­pect of the out­break is that the virus has for the first time hit West Africa. Un­til now, the virus had re­mained con­fined to the back­woods of east­ern and cen­tral Africa. How did the virus travel to West Africa and cause epi­demic? Un­der­stand­ing this is the first step in pre­vent­ing fu­ture epi­demics from hap­pen­ing.

What leads to its emer­gence

Stud­ies show the virus is alien to hu­mans. It is har­boured by fruit bats and a few species of chim­panzees that live in deep forests. As peo­ple come in con­tact with th­ese wild an­i­mals, the virus gets an op­por­tu­nity to in­fect hu­mans. “For­merly spo­radic... the deadly Ebola haem­or­rhagic fever out­breaks are be--

com­ing more and more fre­quent in Africa,” say African and US ex­perts in a 2012 study pub­lished in On­der­stepoort Jour­nal of Vet­eri­nary Re­search. This is mostly due to in­creas­ing con­tact with the in­fected wildlife, they say.

An out­break of Ebola in Gabon in 1994 is thought to have started after gold min­ers ate an in­fected go­rilla. More than 30 peo­ple had died. While bush meat is a del­i­cacy in the re­gion, peo­ple in West Africa are fond of eat­ing fruit bats in stews. The cur­rent Ebola strain has been trans­mit­ted by fruit bat, ac­cord­ing to a re­search pa­per, ti­tled “Out­break of Ebola Virus Dis­ease in Guinea: Where Ecol­ogy Meets Econ­omy”, pub­lished in PLoS Ne­glected Trop­i­cal Dis­eases in July this year.

Some sci­en­tists, how­ever, say cooked meat is not a risk as the virus is killed on cook­ing. In most out­breaks, Ebolavirus is in­tro­duced into hu­man pop­u­la­tions via han­dling of in­fected an­i­mal car­casses, says J J Muyembe, one of the re­searchers of the 2012 study. “De­for­esta­tion may be the in­di­rect cause,” he says. “Bats may mi­grate to the vil­lages in search of fruits. For ex­am­ple, the aban­doned gold mine of Go­rumbwa in Watsa (in Congo) was the source of Mar­burg virus out­break in 1999,”adds Muyembe.

Fig­ures for de­for­esta­tion support his ob­ser­va­tion.In re­cent years, Ebola has struck all coun­tries that have lost large tracts of forests. Ac­cord­ing to the UN En­vi­ron­ment Pro­gramme (unep), Guinea has lost 20 per cent of its forests since 1990.Ac­cord­ing to the 2012 re­port of non-profit Global Wit­ness, more than half of Liberia’s forests have been given to log­ging com­pa­nies. Nige­ria is among the top 10 coun­tries at the high­est risk of de­for­esta­tion. The sit­u­a­tion is worse in the war­rav­aged Sierra Leone. For­est cover in the coun­try has dropped to 4 per cent.At the present rate of de­for­esta­tion, it could dis­ap­pear by 2018,says unep (see ‘Out of the jun­gle’).

As con­flicts and ex­treme weather force peo­ple to ven­ture deeper into the forests in search of newer means of liveli­hood, to hunt bush­meat and plun­der caves, they come in con­tact with the wildlife that carry Ebola (see ‘Ebola is the re­sult of... ’on p16).

Once the virus in­fects a per­son, it trans­mits to fam­ily mem­bers or health­care staff through body flu­ids, es­pe­cially blood. Since Ebola is seen as a so­cial stigma in Africa, pa- tients refuse to be quar­an­tined. This, along with cul­tural prac­tices like rub­bing down bod­ies at fu­neral rites be­fore in­ter­ment, con­trib­ute to the spread­ing of the out­break.

While biological and eco­log­i­cal fac­tors have driven emer­gence of the virus from the for­est, the so­cio-po­lit­i­cal land­scape dic­tates where it goes from there—an iso­lated case or two, or a large and sus­tained out­break, says the PLoS Ne­glected Trop­i­cal Dis­eases study. Un­like pre­vi­ous out­breaks, where the dis­ease re­mained con­fined to scat­tered re­mote ar­eas, this time the virus has spread to ur­ban ar­eas, in­clud­ing cap­i­tal ci­ties.

“Out­breaks like Ebola are more of a de­vel­op­men­tal prob­lem,” says K K Datta, for­mer di­rec­tor of the Na­tional Cen­tre for Dis­ease Con­trol, Delhi.

The US’ Cen­ters for Dis­ease Con­trol, on its web­site, also men­tions that ac­tiv­i­ties like lay­ing roads for log­ging, which lead to frag­men­ta­tion of habi­tats, and bush­meat trade are re­spon­si­ble for emer­gence of mi­crobes, such as Ebolavirus, from forests.

An­nie Wilkin­son, re­searcher at the In­sti­tute of De­vel­op­ment Stud­ies in the UK, says high lev­els of mi­gra­tion and mo­bil­ity within and across bor­ders in­creases the like­li­hood that an out­break spreads fur­ther.

In­dia at risk

With more than 44,000 In­di­ans liv­ing in the four af­fected West African coun­tries and the im­por­tant trade relation In­dia shares with the African re­gion, the virus could be just a plane ride away. Union Health Min­is­ter Harsh Vard­han re­cently said in Par­lia­ment that all pre­cau­tion­ary mea­sures were be­ing taken by In­dia to ward off the threat of Ebola dis­ease.All those liv­ing in the af­fected coun­tries will be called back in case the sit­u­a­tion wors­ens, he said. To pre­vent the virus from en­ter­ing the coun­try, the gov­ern­ment has an­nounced screen­ing and track­ing of pas­sen­gers orig­i­nat­ing or tran­sit­ing from af­fected re­gions, and asked peo­ple to de­fer nonessen­tial travel to West Africa.

About 10 trav­ellers who ar­rived at Delhi and Chen­nai air­ports in the first two weeks of Au­gust with symp­toms of Ebola were im­me­di­ately sent for blood anal­y­sis. Test re­sults showed they were not in­fected with the virus.

A non-profit in Kolkata has, mean­while cau­tioned sex work­ers not to en­ter­tain peo­ple from African coun­tries. “If the virus en­ters In­dia, di­ag­no­sis will be a prob­lem.We do not have enough fa­cil­i­ties or funds,” says Datta.

The only treat­ment avail­able for the dis­ease is sup­port­ive ther­apy that in­cludes bal­anc­ing flu­ids and elec­trolytes, main­tain­ing oxy­gen and blood pres­sure and treat­ing the pa­tient for com­pli­ca­tions. “This re­quires proper health­care fa­cil­i­ties, ster­il­i­sa­tion of equip­ment and pro­tec­tive cloth­ing for health work­ers,”says Sampa Mi­tra, depart­ment of epi­demi­ol­ogy, All In­dia In­sti­tute of Hy­giene and Pub­lic Health in Kolkata. “Even th­ese are not avail­able in the coun­try,” she adds.

Given the load of in­fec­tious dis­eases in the coun­try, In­dia must be on guard till treat­ments for the fa­tal dis­ease are avail­able.

De­layed in­ter­ven­tion

Since 1976,there have been almost two dozen out­breaks of Ebola in about 10 coun­tries in the cen­tral and east­ern parts of the con­ti­nent. Yet treat­ment has not moved beyond the ex­per­i­men­tal stage. For in­stance, re­searchers at Univer­sity of Cam­bridge, UK, and the New Ibe­ria Re­search Cen­ter, US, have tested an Ebola vac­cine on cap­tive chim­panzees with suc­cess. “It is safe and im­muno­genic,” they write in the jour­nal pnas this year.But they have been wait­ing to con­duct clin­i­cal tri­als of the vac­cine on hu­mans.

Two health pro­fes­sion­als from a US-based non-profit Sa­mar­i­tan’s Purse who con­tracted the dis­ease in Liberia and are un­der treat­ment in At­lanta have shown signs of im­prove­ment after they were given an ex­per­i­men­tal drug ZMapp. ZMapp is a serum man­u­fac­tured by Mapp Bio­phar­ma­ceu­ti­cal of San Diego and De­fyrus Inc of Toronto.

The who has also an­nounced that clin­i­cal tri­als of a vac­cine were set to get un­der way, with wide­spread use pre­dicted by early 2015.The vac­cine, be­ing de­vel­oped by Bri­tish drug maker Glax­oSmithK­line in part­ner­ship with the US sci­en­tists, has shown promis­ing re­sults in stud­ies on pri­mates.

What had stopped th­ese com­pa­nies from con­duct­ing clin­i­cal tri­als be­fore? Fund­ing and in­ad­e­quate health in­fra­struc­ture have a ma­jor role to play in out­breaks like th­ese, Tarik Jasare­vic, spokesper­son of who told Down To Earth. A few re­searchers say there was not much in­ter­est or funds to study the dis­ease that af­fected only the poor liv­ing in the hin­ter­lands. This is for the first time the virus has af­flicted those liv­ing in ur­ban ar­eas, in­clud­ing cap­i­tal ci­ties, and a few for­eign na­tion­als. On Au­gust 12,a Span­ish priest suc­cumbed to the virus in a Madrid hos­pi­tal.He con­tracted the dis­ease in Liberia. Ear­lier, a US na­tional work­ing with the Liberian gov­ern­ment had also suc­cumbed to the dis­ease in Nige­ria.

One hopes that an ef­fec­tive treat­ment against the elu­sive dis­ease would now be avail­able with­out fur­ther de­lay. For more on Ebola out­break go to


Vol­un­teers carry bod­ies at an Ebola treat­ment cen­tre run by Medecins

Sans Fron­tieres in Kailahun, Sierra Leone, on July 18

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