How to fix Error in ode45 in matlab

Hi friends I have both script and function file that come up with the error below. The files are expected to solve Epidemic model and plot out put. I need assistance please

the files:

function dydt = naijacfun(t,y)
% state variables
S = y(1);
E = y(2);
I = y(3);
J = y(4);
K =y(5);
R = y(6);
D = y(7);
% model parameters
alphae = 0.59;eta2 = 0.3;gammac = 0.4;deltac = 0.1;alphaa = 0.2456;  
alphas = 0.361;eta1 = 0.2;sigma = 0.192;gammaa = 0.142;gammas = 0.143;deltas = 0.043;
dydt = zeros(2,1);
%The model equations
dydt(1) = - S*(alphae*E+alphaa*I+alphas*J+ alphac*K);  
dydt(2) =  S*(alphae*E+alphaa*I+alphas*J+ alphac*K )-sigma*E;
dydt(3) = (1-eta1-eta2)*sigma*E-(gammaa*I);
dydt(4) = eta1*sigma*I-(gammas+deltas)*J;
dydt(5) = eta2*sigma*I-(gammac+deltac)*K;
dydt(6) = gammaa*I1+gammas*I2+gammac*I3;
dydt(7) = deltas*I2+deltac*I3;
end

I got the following error massage

Error in ode45 (line 115)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in naijacscript (line 4)

[t,y] = ode45(@naijacfun,tspan, y0)

[Walter Roberson]

Unrecognized function or variable 'alphac'.

You initialize alphaa, alphae, alphas, but not alphac