matlab - Parameter estimation for epidemic models -

i have epidemic model:

function ypsirid = ypsirid(t,y) global q m b r ypsirid(1) = q - m*y(1) - b*y(1)*y(2); ypsirid(2) = (b*y(1)*y(2)) - (m+r)*y(2); ypsirid(3) = (r*y(2)) - m*y(3); ypsirid = ypsirid(:) 

can kindly suggest easiest possible method carry out parameter estimation using matlab. thanks!