Dynamic changes of platelets during Plasmodium cynomolgi infection and after drug treatments in rhesus monkeys / 中华传染病杂志

ABSTRACT

Objective To observe platelet dynamics in a monkey infected with Plasmodium cynomolgi before and after treatments with antibiotics and antimalarial drug. Methods One experimental monkey was examined for parasite density and platelet count 2 days after parasite inoculation. Observation without treatment continued for 24 days after the parasite was detected in the blood sample of the monkey. Then the monkey was treated with Azithromycin (total 1500 mg) for 3 days. Thirty days after parasite detection in the blood, the monkey was treated with Artesunate for 5 days. Parasite density and platelet count were monitored daily during treatments. The result was compared with that from a healthy monkey as control. Results The experimental monkey's platelet count was 240× 109/L before infection. When parasite density was 2/100 white blood cells (WBC),platelet count increased to 540 × 109/L. During the subsequent period of infection, parasite density fluctuated at (1-60)/100 WBC, and the platelet count reduced to a persistent level of (130-150)×109/L. After the infected monkey was treated with Azithromycin, parasite density reduced initially but subsequently fluctuated at (16-64)/100 WBC. Meanwhile, platelet count was restored to 234.5 × 109/L.The infected monkey was treated with Artesunate and parasite clearance time was 64 hours, and the mean platelet count was 247 × 109/L after treatment. Conclusion Azithromycin and Artesunate treatment have direct influence on the recovery of platelet counts during malaria infection in monkeys.