New phone tech­nol­ogy to help fight river blind­ness

Africa Renewal - - Africa Wired - BY

Us­ing the pop­u­lar iPhone smart­phone, re­searchers at US-based Stan­ford Univer­sity have cre­ated a sim­ple, por­ta­ble and in­ex­pen­sive di­ag­nos­tic tool to di­ag­nose river blind­ness, a trop­i­cal dis­ease caused by par­a­sitic worm lar­vae from an in­fected fly.

An easy-to-set-up mi­cro­scope called Cel­lS­cope Loa is at­tached to an iPhone, making it pos­si­ble to drop a pa­tient’s blood into the mi­cro­scope’s com­part­ment for ex­am­i­na­tion.

Ev­ery year, ac­cord­ing to the World Health Or­ga­ni­za­tion ( WHO), more than 18 mil­lion peo­ple in Africa and other parts of the world are af­fected by river blind­ness af­ter be­ing bit­ten by the Simulium fly. This fly, found in parts of Africa, the Mid­dle East and South Amer­ica, can eas­ily be dis­missed as an or­di­nary pesky in­sect. But by sim­ply bit­ing the skin, an in­fected fly can de­posit par­a­sitic worm lar­vae into the blood­stream. An in­fected per­son may suf­fer a litany of skin prob­lems and, in the worst cases, blind­ness.

Ac­cord­ing to WHO, the Simulium fly is usu­ally found swarm­ing around rivers in re­mote ar­eas and can carry worm lar­vae that cause a dis­ease called on­chocer­ci­a­sis, com­monly known as river blind­ness. This in turn causes spots on the skin that can re­sem­ble the rough skin of a lizard, as well as in­tense, al­most un­bear­able itch­ing when the hun­dreds of lar­vae nes­tled within the body die.

How­ever, the most se­ri­ous dam­age on­chocer­ci­a­sis can cause is dam­age to the op­tic nerve, of­ten re­sult­ing in per­ma­nent loss of vi­sion. Ac­cord­ing to WHO, this is the sec­ond most com­mon in­fec­tious cause of blind­ness glob- ally. No vac­cines ex­ist against the dis­ease yet and pa­tients must take the pre­scribed med­i­ca­tion twice a year for 15 years. Ev­ery year phar­ma­ceu­ti­cal com­pany Merck, WHO and other part­ners or­ga­nize a do­na­tion pro­gramme in which the drug Mec­ti­zan is given to river blind­ness pa­tients. Sim­i­lar do­na­tion pro­grammes in Ethiopia, Nige­ria, Su­dan and Uganda, among other coun­tries, have been car­ried out to cure mil­lions of those af­fected.

Un­for­tu­nately, many of th­ese pro­grammes have re­cently been halted be­cause the drug may pose a risk to pa­tients who suf­fer from two other par­a­sitic diseases that worms that cause all three diseases, it can cause harm to pa­tients who have too many Loa loa worms in their blood­stream by wip­ing them all out at once, caus­ing haem­or­rhag­ing of the brain, ac­cord­ing to WHO. The Cel­lS­cope Loa was cre­ated to avoid the risk of mis­di­ag­no­sis.

Lab tech­ni­cians can ex­am­ine blood smears and man­u­ally iden­tify and count the worms, a process that can take most of a day. Given the num­ber of pa­tients to be tested, this is very time- con­sum­ing and of­ten im­prac­ti­cal.

Once the Cel­lS­cope Loa— in­vented by Stan­ford Univer­sity re­searchers Thomas Nut­man and Dan Fletcher—is at­tached to an iPhone, a pa­tient’s blood can be dropped into the mi­cro­scope’s com­part­ment for test­ing. Through use of the iPhone’s in­ter­nal cam­era, re­sults of the test can be ob­tained within two min­utes and can in­clude the num­ber of Loa loa worms present in the sam­ple. Based on this pro­ce­dure, it can be de­ter­mined whether med­i­ca­tion for river blind­ness needs be given to the in­fected pa­tient.

The mi­cro­scope can save pre­cious time and be­cause it works with a prompt-based in­ter­face, telling the user the ex­act steps to take, hu­man er­ror is min­i­mized.

The Stan­ford Univer­sity pro­gramme to man­u­fac­ture th­ese mi­cro­scopes is be­ing funded by the Bill and Melinda Gates Foun­da­tion, the US Agency for In­ter­na­tional De­vel­op­ment and the Blum Cen­ter for De­vel­op­ing Economies at the Univer­sity of Cal­i­for­nia Berke­ley.

The re­searchers are cur­rently test­ing the de­vices and cre­at­ing ap­prox­i­mately 40 more. So far the re­sults have been en­cour­ag­ing. An ini­tial test was con­ducted in Cameroon. The sec­ond batch of mi­cro­scopes is be­ing tested in cen­tral Africa.

If fu­ture ex­per­i­ments with the smart­phone mi­cro­scope con­tinue to pro­duce ac­cu­rate re­sults, per­haps there is a fu­ture in point- of- care di­ag­noses, es­pe­cially of trop­i­cal diseases.

“It demon­strates what tech­nol­ogy can do to help fill a void for pop­u­la­tions that are suf­fer­ing from ter­ri­ble, but treat­able, diseases,” says Mr. Fletcher.

NIAID

Test­ing of the mo­bile phone-based video mi­cro­scope in Cameroon.

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