| Objective: Plasmodium.vivax malaria is a global health problem and China plans to eliminate malaria by 2020.But this is challenged by the difficulty of radical cure treatment for P.vivax.High recrudescenses of P.vivax malaria are common after treatment with chloroquine plus primaquine.At present,resistance of P.vivax to chloroquine has also been found in some areas.Chloroquine plus primaquine 8-day therapy is a first-line treatment for P.vivax in China.In this study,the aim is to explore the risk factors for the failure of chloroquine plus primaquine 8-day therapy in the treatment,including the factors affecting the slow clearance of asexual parasite clearance by chloroquine and the failure of radical cure vivax malaria by primaquine for the purpose of providing theoretical basis and technical support to further improving the radical cure rate of P.vivax.Methods: A clinical trial site was carried out in the Centers for Disease Control and Prevention in Tengchong County and Yingjiang County Yunnan Province.The patients with fever were examined by microscopy and their body temperatures were also taken.The patients with single infection of P vivax malaria were recruited in this study.Parasite density and blood test were detected.Information such as age and sex were recorded.Chloroquine tablets for different categories of kg body weight ranges were given once a day for three days.Primaquine tablets for different age ranges were given once a day for 8 days and followed-up for 365 days.Before the blood malaria parasites were cleared,the temperature of the patient was taken every eight hours and blood was collected to make blood smears and filter paper dried blood spots until two consecutive negativities by microscopy.And then the patients were followed-up on day 7、14、21 and 28,respectively.After 28 days,they were followed-up once a month until 1 year.Body temperature were recorded,blood were collected and asked if there was another fever in order to determine if there was any recrudescense.Microscopy was used to identify P.vivax infection during follow-up.PCR was conducted to distinguish between re-infection and recrudescense,to confirm the parasite species during follow-up.Using SPSS software input and analyze data.Rank sum test and spearman nonparametric test were used to analyze the correlation between asexual parasite clearance times and various factors in chloroquine treatment P.vivax malaria.The correlation was analyzed by P value and correlation coefficient R.The two classified logistics regression analysis was used to analyze the factors related to the slow effect of chloroquine and the failure of primary radical cure.The correlation was analyzed by the R and P.Results: A total of 185 cases of effective case data were collected,including 163 male patients and 25 female cases.The majority of age was 16-45 years within the youth stage,male majority.The correlation coefficient between the initial day of malaria parasite and asexual parasite clearance time was 0.333(P<0.05).The correlation between these was statistically significant(R=1.000,P=0.016).A total of 175 cases were completed at the 1-year follow-up.There were 40 cases of recrudescense in a year and 135 cases of radical cure.The cure rate was 77.1%(95% CI: 76.9%-77.3%).The correlation analysis of the initial day of malaria parasite Rs =0.348,asexual parasite clearance times Rs=0.448,and all the P values were <0.05.The results of two classified logistics regression analysis show statistically significant difference(R=1.110,P<0.001).In addition,the average dose of primaquine in the radical cured cases was 3.123(95% CI: 3.0323-3.2137)mg/kg,and it in relapse cases was 2.8864(95% CI: 2.7780-2.9948)mg/kg.The ratio was 1:0.811.The results of the two-class logistic regression analysis were statistically significant difference(R = 0.189,95% CI: 0.061-0.586,P = 0.04).Conclusion: The results of two statistical analysis methods showed that the initial day of malaria parasite was significantly correlated with the asexual parasite clearance times;and the initial day of malaria parasite affected the clearance effect of chloroquine treatment of P.vivax.The radical cure rate of primaquine was correlated with malaria parasite density in initial days,the sexual parasite clearance times and the body weight dose of primaquine.It indicated that malaria parasite density in initial days and the body-weight dose of primaquine affected the radical cure effect of P.vivax. |
