A 3-STATE MARKOV MODEL OF PLASMODIUM-FALCIPARUM PARASITEMIA

A three-state Markov model taking into account clinical signs of malar ia infections by P. falciparum is described. The three states consider ed are the noninfected (state 0), the infected exhibiting no clinical signs (state 1), and the infected with clinical signs (state 2). Metho ds for estimating the transition rates from longitudinal data are indi cated. This model was used to assess the effect on children of an inte rvention trial on the use of mosquito nets impregnated with insecticid e. The trial was conducted in West Africa (Burkina Faso) between 1985 and 1987. The analysis showed that the intervention was most effective on transition rates between state 1 and state 2.