I-epidemiology inokubala ukuba zeziphi izifo ezasasazekayo
Ngamanye amaxesha isifo sisasazeka njengomlilo. Abanye a ba Ezinye izifo zifa nje. Sifumana njani ukuba zeziphi izifo eziza kusasazeka kwaye ezingenako?
Ewe, kukho ixesha eli, R0, elibizwa ngokuthi "Naught". Khawucinge ngeklasi ye-1st graders. Omnye ufika esikolweni egulayo.
Ukugula komntwana ogulayo kuchaphazela omnye umntwana. Umntwana wesibini unokusulela umntwana omnye; umntwana wesithathu angasifaka omnye.
I-chain of infections ingasasaza isifo kuyo yonke iklasi.
Kwi-epidemiology, le nto esiyibiza ngesifo nge-R0 ye-1. nganye ityala likhokelela kwimeko entsha entsha.
Inkcazo
I-R0 yile nombolo yokuzala. Ichaza ukuba zininzi iintsana eziya kugula xa umntwana ogulayo engena egumbini (kubemi) kunye nabo bonke abantwana bayakwazi ukugula (banokuthi banokugula). Kuxhomekeke kokubili kwisifo ngokwayo kunye nokusebenzisana kwezingane.
Xa ama-R0 aphezulu kune-1, abantwana abaninzi banesifo. I-R0 ephezulu ayiyona isifo esiyingozi. Ingqele ingaba ne-R0 ephezulu; isifo esinqabileyo kodwa esibulalayo sinokuxabiseka okuphantsi, ngaphantsi kwe-1.
Ngoku ubuyele eklasini.
R0 <1
Cinga ukuba, ngokuqhelekileyo, akuyena wonke umntwana osuleleke omnye umntwana. Umntwana wokuqala uphatha isibini; okwesibini, okwesithathu. Nangona kunjalo, mhlawumbi yesithathu ayifuni nantoni na.
Isifo siyayeka ukusasazeka.
Oku kwenzekayo xa i-R0 ingaphantsi kwe-1.
Abantwana bangagula kuqala, kodwa eso sifo siya kuphuma.
R0> 1
Masibuyele kumntwana wokuqala, ngoku sicinga ukuba lo mntwana uchaphazela 2, abo banabantwana aba-2 baphatha 2 ngamnye (4 bonke ndawonye). Ingqikithi, i-7 iya ku suleleka. I-4 yokugqibela inokuthelela i-2 nganye, ekhokelela kwizifo ezingama-15 ezipheleleyo. Kungekudala, bekuza kubakho abantwana abaninzi abagulayo.
Oku kwenzekayo xa i-R0 ingu-2 kwaye akukho gciwane eligulayo eligcinwa ekhaya.
Ukungahambi
Ubomi bobubomi, kungekhona wonke umntu okwazi ukubamba i-bug. Abanye abantwana banokugonywa. Abanye baya kugula baze bangaguli kabini ngexesha elifanayo. Abanye abantwana baya kugula, bafumane kwakhona kwaye bajonge. Sithetha ukuba akusiwo wonke umntu "ongenakwenzeka".
Ngokuqhuma okuqhubekayo, "Ixabiso elivelisayo lokuzalisa" (R) lichaza isifo esisasazekayo. Le yenani labantwana abagulayo kwiklasi edibanisa abantwana abangakwazi ukugula kunye nabantwana abakwaziyo. (R ukwanda kunye nenani elithintekayo. R = R0x, apho x i-fraction ingabonakali)
Inani elinokuthi liza kutshintshwa ngexesha lokuqhambuka, njengoko abantwana abaninzi begula baze bafumane okanye bagonywe. Ukudibanisa izigulane ezigulayo, iintsholongwane zomzimba kunye nezingane ezifunyenwe nazo zingenako ukufana.
Umngcipheko weHerd
Ukuba inkwenkwe yokuqala yangena kwigumbi ezele abantwana abakhuselekile, lesi sifo sasingasasazeka. Ukuba phantse zonke iigusha zase zigule kwaye zikhuselekile, isifo asiyi kusasazeka. Ukuba abantwana abathathu kwaba-10 baphelelwe igciwane, mhlawumbi isifo asiza kusasazeka. Umntwana ogulayo akanako ukusebenzisana nabantwana aba-2 kwabashumi abaya kugula.
Siyibiza ngokuba ngumzimba wokhuseleko lomzimba. Oko kukuthi, ukukhuseleka kwabantwana abathile kukhusela abanye abantwana abangenagciwane lokugula.
Ingqengqwana yezingane ezikhuselekileyo njengokuba imvana nganye inomntwana oyedwa ogulayo (ngokuqhelekileyo). Ukuba enye intsana ikhuselekile, isifo asiyi kusasazeka.
Ukuba i-R0 ikhulu, ukukhuselwa komzimba kukhusela kuphela ukuba abaninzi banokuzivikela. (Umgca we-Herd Immunity threshold = 1 - 1 / R0) Omkhulu we-R0, abantwana abaninzi kufuneka bagonywe.
Abasasazeli abakhulu
Abanye abantwana basasaza ukugula ngaphezu kwabanye - njengotitshala ogulayo osebenza kunye neyodwa yintsana. Ukuqubuka kungabonakala nzima kuneR0.
ZoBomi zekelo
Esinye sezifo ezithathelwanayo sisisombululo kunye ne-R0 phakathi kwe-12-18. Ngaphambi kokugonywa kwe-measles, umntwana angaphatha abantwana aba-15 kwelinye igumbi lokufundela.
Abo bafunda nabo be-15 nabo babeza kubachaphazela bonke abafundi be-15 esikolweni. Iifama zisasazeka ngokukhawuleza. Ukuze ugweme ukusabalala, ama-83-95% kufuneka agonywe.
Sibala i-R0 ngokuqwalasela ukuba isifo sisasazeka njani ngokukhawuleza. I-Ebola ka-R0 inokwenzeka 1.34, 1.86 okanye 1.6-2.0. Ibhokotshi yapheliswa ngu-R0 we-3.5-6 efuna i-8 ukuya kwe-10 ukuba ikhuselwe ngumzimba. I-Pertussis (i-Cowing Cough) ine-R0 ephezulu: 15-17 . Ukungabikho kweTiberculosis 'R0 = 10 ngelixa i-R0 yentsholongwane idla ngaphantsi kwe-2.
Siyakwazi ukuqikelela u-R0 kubathintana nabo. Kwiklasini, umnxibelelwano unokuba ngaba bantwana badlala iibhloko kwaye batyelela ezandleni zabo, besasazeka intsholongwane. Ixabiso eli-R0 lixhomekeke kule fowuni. Kuxhomekeke ekubeni ixesha elide ixesha lokugula lihlala phi, zingaphi iinkcukacha ezinxulumene nebhokhwe xa zigula, zingaphi ukugula kusasazeka ngexesha loqhagamshelwano.