I-epidemiology ingabala ukuthi iziphi izifo ezisakazekayo
Ngezinye izikhathi isifo sisakazeka njengomlilo oshisayo. Abanye abakwenzi. Ezinye izifo ziphela nje. Sithola kanjani ukuthi iziphi izifo ezizosabalalisa futhi aziphi?
Yebo, kukhona isikhathi salokhu, R0, ebizwa ngokuthi "Naught". Cabanga ngesigaba sabadobi bokuqala. Omunye ufika esikoleni egula.
Ukugula kwengane egulayo kugula enye ingane. Ingane yesibili ingabe isifo ingane eyodwa; ingane yesithathu ingadala omunye.
I-chain of infections ingasakaza lesi sifo kulo lonke ekilasini.
E-epidemiology, yilokhu esikubiza ngesifo nge-R0 ye-1. Icala ngalinye liholela esimweni esisodwa esisha.
Incazelo
I-R0 iyinamba eyisisekelo yokuzala. Lichaza ukuthi zingaki izingane ezizogula uma ingane eyodwa egulayo ingena ekilasini (isibalo) futhi zonke izingane ziyakwazi ukugula (ziyakwazi). Kuxhomeke kokubili ngesifo ngokwayo kanye nokusebenzisana kwezingane.
Lapho ama-R0 ephakeme kune-1, izingane eziningi zinegciwane. I-R0 ephezulu akuyona isifo esiyingozi kakhulu. Umkhuhlane ungaba ne-R0 ephezulu; isifo esingavamile kodwa esibulalayo singaba nesilinganiso esincane, ngaphansi kwe-1.
Manje buyela ekilasini.
R0 <1
Cabanga ukuthi, ngokwesilinganiso, akuzona zonke izingane ezithathelwana enye ingane. Ingane yokuqala ithinta okwesibili; okwesibili, okwesithathu. Kodwa-ke, mhlawumbe okwesithathu akutheleleli noma yikuphi.
Ukugula kuzoyeka ukusabalalisa.
Yilokho okwenzekayo uma i-R0 ingaphansi kwe-1.
Izingane zingase zigule ekuqaleni, kodwa lesi sifo sizokhipha.
R0> 1
Ake sibuyele kumntwana wokuqala, manje ake ucabange ukuthi le ngane ihlasela 2, labo bantwana ababili baphatha 2 ngamunye (4 bonke ndawonye). Ingqikithi, 7 izobe igciwane. Owesishiyagalolunye angaphethelela u-2 ngamunye, okuholela ekutheni izifo ezingu-15 ziphelele. Ngokushesha, bekuyoba nezingane eziningi ezigulayo.
Yilokho okwenzekayo uma i-R0 ingu-2 futhi akukho kid egulayo egcinwa ekhaya.
Ukwehluleka
Ekuphileni kwangempela, akuwona wonke umuntu okwazi ukubamba lesi sigciwane. Ezinye izingane zingagonywa. Abanye bayobulala futhi abakwazi ukugula kabili ngesikhathi esifanayo. Ezinye izingane zizogula, zithole futhi zivikeleke. Sisho ukuthi akuwona wonke umuntu "ongathinteka".
Ekuqhumeni okuqhubekayo, i- "Izinga Lokukhiqiza Eliphumelelayo" (R) lichaza ukusakazeka kwesifo. Lona inani lezingane ezigula eglasini elinokuxuba kwezingane ezingenakugula kanye nezingane ezingakwazi. (R ukwandisa nge-proportion etholakalayo. R = R0x, lapho x ingxenyana etholakalayo)
Inombolo engakwazi ukushintsha iyoshintsha ngesikhathi sokuqubuka, njengoba izingane eziningi zigula futhi zilula noma zigonywa. Ukuhlanganiswa kwegciwane, igciwane lesandulela ngculazi kanye nezingane eziphulukile kungase futhi kungabi yinto efanayo.
Umkhuhlane we-Herd
Uma ingane yokuqala ingena egumbini eligcwele izingane ezizivikelekile, lesi sifo ngeke sisakaze. Uma cishe zonke izinyane lase ligula futhi selikhulelwe, lesi sifo sasingeke sisakaze. Uma izingane ezingu-8 kwabayishumi zigonywe, lesi sifo cishe sasingeke sisakazeke. Inyane eligulayo lingase lihlanganyele nabantwana ababili kwabangu-10 abangagula.
Sibheka le nsima yomzimba. Okusho ukuthi ukuzivikela kwabanye abantwana kuvikela ezinye izingane ezingekho-immune ukugula.
Ingxenyana yezingane ezizivikela ngculazi kangangokuthi ingane ngayinye ithola ingane eyodwa kuphela egulayo (ngesilinganiso). Uma izinyane elilodwa elithile lingama-immune, lesi sifo ngeke sisakaze.
Uma i-R0 inkulu, imfutho yegciwane lengculazi ivikela kuphela uma abaningi bengama-immune. (Umgogodla wegciwane lengculazi = 1 - 1 / R0) Kakhulu i-R0, izingane eziningi zidinga ukugonywa.
Abashumayeli abaphezulu
Ezinye izingane zisakaze ukugula okuningi kunabanye - njengomfundisi ogulayo osebenza nayo yonke imbuzi. Iziqhumane zingase zibe nzima kunama-R0.
Izibonelo Eziphilayo Zokuphila
Esinye sezifo ezithathelwanayo kakhulu yizimpukane ezine-R0 phakathi kuka-12-18. Ngaphambi kokugoma imishanguzo, ingane ingaphazamisa izingane ezingu-15 ekilasini elilodwa.
Labo abafunda nabo ekilasini abangu-15 bangase bahlulele abafundi abangu-15 esikoleni. Izitshalo zisakaza ngokushesha. Ukuze ugweme isishukela, u-83-95% udinga ukugonywa.
Sibala i-R0 ngokubheka ukuthi lesi sifo sisakazeka kanjani ngokushesha. I-Ebola's n R0 cishe i-1.34, 1.86 noma i-1.6-2.0. Isikhumba saphelelwa yisikhathi ngo-R0 we-3.5-6 okwakudingeka ukuthi kwaba ngu-8 kwabayishumi ukuzivikela. I-Pertussis (i-Whooping Cough) ine-R0 ephezulu: 15-17 . Ukungenwe yisifo sofuba 'R0 = 10 ngenkathi i-R0 yomkhuhlane ngokuvamile ingaphansi kuka 2.
Singakwazi futhi ukulinganisa u-R0 oxhumana nabo. Eklasini, othintana nabo bangase babe izingane ezidlala amabhlogo bese behlunga ezandleni zabo, besakaze ukutheleleka. Inani le-R0 lincike kulolu xhumana. Kuncike ekuguleni isikhathi esingakanani, ukuthi bangaki oxhumana nabo abanezinyane uma begula, kungakanani ukugula okusakazeka ngesikhathi soxhumana nabo.