Ucwaningo olusha lusebenzise ukuhlolwa kwerobhothi ukuthola uhlu olufushane lwenhlanganisela yamakhemikhali okungenzeka 'kuvimbele' umalaleveva
Ngokusho kwe-WHO, kube nezigameko ze-malaria eziyizigidi ezingu-219 emhlabeni wonke kanye nokufa okulinganiselwa ku-435,000 ngo-2017. Umalaleveva yisifo esithathelwanayo esibangelwa izimuncagazi iPlasmodium falciparum noma iPlasmodium vivax. Lama-parasite aqala umjikelezo wawo wokuphila lapho umiyane onaleli gciwane edlulisela ama-sporozoite kumuntu lapho edla igazi lomuntu. Amanye alawa ma-sporozoite adala ukutheleleka ngaphakathi kwesibindi somuntu njengoba ephindaphinda. Kamuva, i-parasite iqhuma ibe amangqamuzana abomvu egazi ukuze iqale ukutheleleka. Uma igazi litheleleka, izimpawu zikamalaleveva njengokugodola, imfiva njll. zivela kumuntu.
Okwamanje iyatholakala izidakamizwa Umalaleveva ngokuvamile udambisa izimpawu zesifo 'ngemuva' kokutheleleka. Bavimba ukuphindaphindeka kwama-parasite egazini lomuntu, nokho abakwazi ukuvimba ukusulelana kwabantu abasha ngomiyane ngoba ukutheleleka sekuvele kwenzeka. Lapho umuntu onaleli gciwane elunywa umiyane, umiyane uthwala leli gciwane liye komunye umuntu oqhubeka nomjikelezo omubi wokutheleleka. Ngeshwa, izimuncagazi zikamalaleveva seziqala ukumelana neziningi ezitholakala ngokudayisa izidakamizwa zokulwa nomalaleveva. Kunesidingo esiphuthumayo semithi emisha yokunqanda umalaleveva engakwazi nje ukwelapha izimpawu kodwa futhi ivimbele ukutheleleka kamalaleveva ukuthi kungangeni egazini ukuze kungadluliselwe kwabanye abantu.
Ukukhomba isiteji esisha kumjikelezo wokuphila we-parasite
Esifundweni esisha esishicilelwe ku- Isayensi, abacwaningi baqonde i-parasite ye-malaria isesigabeni sangaphambili somjikelezo wokuphila - okungukuthi lapho i-parasite iqala ukuthelela isibindi somuntu. Lokhu kungaphambi kwesigaba lapho i-parasite iqala ukuphindaphinda egazini futhi ibangele ukutheleleka kumuntu. Abacwaningi bathatha iminyaka emibili ukukhipha amagciwane kamalaleveva ezinkulungwaneni zomiyane besebenzisa ubuchwepheshe besimanje bamarobhothi. Ocwaningweni lwabo, basebenzisa i-Plasmodium berghei, i-parasite ehlobene ethelela amagundane kuphela. Okokuqala, omiyane bangenwa yi-parasite, bese kuthi ama-sporozoite akhishwe kulawa omiyane abangenwe yileli gciwane - amanye awo omisiwe, eqhwa ukuze angabi nalutho. Lawa ma-sporozoite abe eseyiswa endaweni yokuhlolwa kwezidakamizwa lapho izidakamizwa ezingase zibe khona/ama-inhibitor/izinhlanganisela zamakhemikhali zahlolelwa ukusebenza kwazo. Emzuliswaneni owodwa izingxube ezingaba ngu-20,000 zingahlolwa kusetshenziswa ubuchwepheshe berobhothi namaza omsindo lapho amanani amaminithi ekhemikhali ngayinye yengezwe okungukuthi inhlanganisela eyodwa kwenezelwa iseli ngalinye le-sporozoite. Amandla enhlanganisela ngayinye okubulala i-parasite noma ngisho nokuvimba ukuphindaphinda kwaso ahlolwe. Izinhlanganisela ebezinobuthi kumaseli esibindi zakhishwa ohlwini. Ukuhlolwa kwenzelwe isethi efanayo yezinhlanganisela kwezinye izinhlobo ze-Plasmodium kanye nakwezinye izigaba zomjikelezo wokuphila ngaphandle kwesigaba sesibindi.
Amakhemikhali atholakele
Isamba sezinhlanganisela zamakhemikhali ezingaphezu kuka-500,000 zahlolwa ukuze zikwazi ukunqanda i-parasite lapho sisesigabeni sesibindi somuntu. Ngemuva kwemizuliswano eminingi yokuhlolwa, kufakwe ohlwini lwama-compounds angama-631 abonakale evimba ukutheleleka nge-malaria ngaphambi kokuba izimpawu ziqale ezingase zivimbele ukungenwa kwegazi, omiyane abasha nakubantu abasha. Ama-58 phakathi kwalezi zinhlanganisela ezingama-631 aze avimba inqubo yokukhiqiza amandla ye-parasite ku-mitochondria.
Lolu cwaningo lungaba yisisekelo sokwenza imithi yesizukulwane esilandelayo 'yokuvimbela umalaleveva'. Ucwaningo lwenziwe emphakathini wemithombo evulekile okuvumela amanye amaqembu ocwaningo emhlabeni wonke ukuthi asebenzise lolu lwazi ngokukhululekile ukuze aqhubekisele phambili umsebenzi wawo. Abacwaningi bafuna ukuhlola abantu abangu-631 abathembisayo bezidakamizwa ukuze bahlaziye ukusebenza kahle kwabo futhi lezi zingxube zizodinga ukuthi zibhekwe ukuthi ziphephile yini ukuze zisetshenziswe abantu. Umalaleveva udinga ngokushesha umuthi omusha othengekayo futhi ongalethwa kunoma iyiphi ingxenye yomhlaba ngaphandle kwezidingo ezengeziwe zengqalasizinda, abasebenzi bezempilo noma ezinye izinsiza.
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{Ungafunda iphepha lokuqala locwaningo ngokuchofoza isixhumanisi se-DOI esinikezwe ngezansi ohlwini lwemithombo ekhonjiwe}
Umthombo (s)
U-Antonova-Koch Y et al. 2018. Ukutholwa komthombo ovulekile wamakhemikhali okuholela esizukulwaneni esilandelayo se-chemoprotective antimalarials. Isayensi. 362(6419). https://doi.org/10.1126/science.aat9446
