Man with a mis­sion

De­spite some set­backs, Keer­tan Dheda re­mains com­mit­ted to the fight against TB, writes Ta­mar Kahn

Business Day - - BUSINESS LIFE / TALKING HEADS -

WHEN Keer­tan Dheda grew up in Dur­ban’s Cas­bah sub­urb in the 1970s, din­ner ta­ble con­ver­sa­tions were dom­i­nated by the nu­mer­ous doc­tors in his ex­tended fam­ily. The son of a tai­lor and a house­wife, he longed to join the ranks of the med­i­cal fra­ter­nity, driven by the no­ble idea of heal­ing bro­ken bod­ies.

He re­alised his dream, qual­i­fy­ing as a doc­tor in the early 1990s and went to work at the King Ed­ward Hospi­tal in Dur­ban, where he was con­fronted by a pop­u­la­tion riven by the dis­ease of poverty: tu­ber­cu­lo­sis (TB) was rife and its evil twin HIV raged vir­tu­ally unchecked, as the govern­ment re­fused to pro­vide ac­cess to life­sav­ing an­tiretro­vi­ral medicines. Since HIV weak­ens the im­mune sys­tem, the most com­mon killer among these pa­tients was TB.

It was a turn­ing point in his ca­reer, prompt­ing his de­ci­sion to spe­cialise in re­s­pi­ra­tory medicine and pro­pel­ling him along the path that led to the po­si­tion he holds to­day — head of the pul­monology di­vi­sion at the Univer­sity of Cape Town. He de­fines him­self as a “clin­i­cian sci­en­tist”, com­bin­ing work at the bed­side with med­i­cal re­search. In SA his ilk is “as rare as the rhino”, he laments, ex­plain­ing that the paucity of govern­ment fund­ing means there are few posts avail­able for spe­cial­ists who wish to both treat pa­tients and “go and think in dark cor­ners” about sci­en­tific prob­lems.

Dheda is not a man with a care­fully pol­ished script, and he vol­un­teers few anec­dotes or de­tails about his per­sonal life. He rat­tles off his achieve­ments rapid-fire, in an al­most off­hand man­ner, down­play­ing his ex­ten­sive aca­demic ac­com­plish­ments: he was SA’s top ma­tric­u­lant in 1986, won the Suz­man Gold Medal when he was ad­mit­ted to the South African Col­lege of Physi­cians, and won a Bri­tish Lung Foun­da­tion fel­low­ship to study for a PhD at Univer­sity Col­lege Lon­don. He won a pres­ti­gious sci­en­tific award from the In­ter­na­tional Union Against Tu­ber­cu­lo­sis and Lung Dis­ease, has pub­lished over 145 peer­re­viewed re­search pa­pers, and ear­lier this year won the highly sought-af­ter Harry Op­pen­heimer Fel­low­ship Award that is “granted to schol­ars of the high­est cal­i­bre who are en­gaged in cut­ting-edge, in­ter­na­tion­ally sig­nif­i­cant work”.

Like many sci­en­tists, he is most an­i­mated when talk­ing about his work, which ranges from prob­ing the mys­ter­ies of how the body’s im­mune sys­tem at­tempts to fend off TB’s at­tack to try­ing to fig­ure out why some pa­tients are so much more ef­fi­cient than oth­ers at spread­ing this deadly dis­ease.

The many failed TB vac­cines show that sci­en­tists still don’t have a good han­dle on the way the im­mune sys­tem re­sponds to the My­cobac­terium tu­ber­cu­lo­sis bac­te­ria, an un­der­stand­ing that is vi­tal if they are to de­sign a vac­cine that can teach the body how to fend it off, says Dheda.

“We just don’t have ad­e­quate knowl­edge about TB

The num­bers are start­ing to over­whelm us and we are mag­ni­fy­ing the prob­lem by send­ing people home to die. We need a new strat­egy, com­bin­ing home-based care, longterm com­mu­nity stay fa­cil­i­ties, and pal­lia­tive care fa­cil­i­ties

to se­lect a good vac­cine. So we have gone back to study the im­munol­ogy of TB in the lung,” he says. One of the ar­eas his team is look­ing at is an ap­par­ent para­dox in which the body’s own im­mune sys­tem ap­pears to sab­o­tage it­self when con­fronted with TB.

His group found that some kinds of reg­u­la­tory T-cells in the lungs, which “stop the body from over­re­act­ing to all the gunk we breathe in ev­ery day”, sub­vert the im­mune sys­tem’s re­sponse to TB and stop it from con­tain­ing the bac­te­ria.

TB is one of the old­est dis­eases known to man, and over the cen­turies it has evolved with an ex­ten­sive bag of tricks to en­able it sur­vive in its hu­man host, in­clud­ing the abil­ity to lie dor­mant for years be­fore rear­ing up to cause full-blown in­fec­tion. Through­out his­tory it has cut a swathe through hu­mankind, killing four out of five people it in­fects. That changed dra­mat­i­cally in the 1940s and 1950s when pow­er­ful new an­tibi­otics were de­vel­oped that turned the dis­ease from an al­most cer­tain killer into one that al­most ev­ery­one sur­vived.

For a brief pe­riod, it seemed as if mod­ern medicine had won. Sadly, that op­ti­mism has long since evap­o­rated, as tu­ber­cu­lo­sis has con­tin­ued to evolve in ways that have pro­vided it with re­sis­tance to one drug af­ter an­other.

To­day the num­ber of pa­tients with mul­tidru­gre­sis­tant TB is soar­ing, and in a com­pletely new way: it used to be a rel­a­tively small prob­lem, largely con­fined to pa­tients who had for one rea­son or an­other failed to con­tinue to take their six-month cock­tail of an­tibi­otics.

Now 80% of drug-re­sis­tant TB is spread from per­son to per­son. Health­care work­ers are at par­tic­u­larly high risk, due to their oc­cu­pa­tional ex­po­sure to the dis­ease: in SA they are six times more likely to be­come in­fected with drug-re­sis­tant TB than people in the gen­eral pop­u­la­tion, ac­cord­ing to a study co-au­thored by Dheda.

So is he wor­ried that he too might be at risk?

“The short an­swer is I don’t think about it”, says Dheda. “No one comes into your of­fice with a sign on their head say­ing ‘I’ve got TB’, so we are con­stantly be­ing ex­posed to it,” he says.

The sheer num­bers of people with drug-re­sis­tant TB in SA — an es­ti­mated 15,000 were di­ag­nosed last year alone — mean iso­lat­ing pa­tients un­til they re­cover is no longer fea­si­ble, says Dheda.

At the mo­ment, many pa­tients who don’t re­spond to treat­ment are sent home once it be­comes clear the hospi­tal can no longer help: since they are still in­fec­tious, they put their friends, fam­ily and people in their com­mu­nity at risk. Dheda made this point in a paper pub­lished ear­lier this year in The Lancet, in which he urged the govern­ment to re­think its ap­proach.

“The num­bers are start­ing to over­whelm us and we are mag­ni­fy­ing the prob­lem by send­ing people home to die,” Dheda says. “We need a new strat­egy, com­bin­ing home-based care, long-term com­mu­nity stay fa­cil­i­ties, and pal­lia­tive care fa­cil­i­ties.”

By analysing pa­tients’ coughs, Dheda’s team has shown that about 80% of TB is trans­mit­ted by a mi­nor­ity of pa­tients dubbed “su­per­spread­ers”. If these pa­tients can be iden­ti­fied, then per­haps pre­cious re­sources can be chan­nelled to­wards them, while those at low risk of spread­ing TB can be treated at home. The team is now try­ing to un­der­stand the ge­netic blue­print of both the host and the bug in the high-risk pa­tients in the hope of find­ing bet­ter ways to con­tain out­breaks.

Dheda has also pushed hard to bring cut­ting-edge tech­nol­ogy to South African pa­tients with re­s­pi­ra­tory dis­eases: Groote Schuur is the only hospi­tal in Africa to of­fer a heat treat­ment called bronchial ther­mo­plasty to se­vere asth­mat­ics, the first non­phar­ma­ceu­ti­cal treat­ment ap­proved by the US Food and Drug Ad­min­is­tra­tion. The pro­ce­dure uses heat to burn off a thin layer of mus­cle cells in­side the lung’s air­ways, which re­duces the in­ci­dence of lifethreat­en­ing asthma at­tacks.

“It’s been a ma­jor ben­e­fit to the health­care sys­tem, be­cause a small group of se­vere asthma pa­tients con­sume prob­a­bly two- thirds of the med­i­cal costs of asthma con­trol,” says Dheda.

Some of his youth­ful ide­al­ism may have been dis­placed by the prag­ma­tism that comes with age, but Dheda re­mains deeply com­mit­ted to the fight against TB.

“As a ju­nior doc­tor I was in­trigued and ap­palled by this in­fa­mous dis­ease that has been the big­gest killer of mankind. We still haven’t got on top of the prob­lem,” he says.

Pic­ture: TREVOR SAM­SON

IDE­AL­IST: Univer­sity of Cape Town head of pul­monology Keer­tan Dheda ad­mits sci­en­tists lack suf­fi­cient knowl­edge.

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