Abstract

The present study designed to evaluate the efficacy of conventional PCR with small – sub unit18S rRNA gene of the liver and spleen tissues in mice infected with 200 μl of 1.2 x 106 inoculum of Leishmania donovani promastigote after 45 and 60 days of infection. The results show positive results in 30 specimens (75%) of liver and 26 specimen (65%) of spleen of infected mice after these periods. Also the results show the amastigote significantly increased (p≤ 0.05) in the number of infected mouse tissue (liver and spleen), large in size of the spleen and significantly increased (p≤ 0.05) in the liver and spleen weight of infected mice after 45 and 60 days from inoculum in comparison with non infected mice, also significantly decrease in Hb, RBC, and WBC in comparison with non infected mice after 60 days. This study concluded that the Balb/c mouse model have good indicator for VL resemble to human VL, and conventional PCR with small 18S rRNA gene have high sensitivity for detection Leishmania donovani in the liver and spleen tissues of mice. Key words: Leishmania donovani, clinical signs, PCR.