***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: ABSTRACT Data from a double-blind r and omized clinical drug trial were analyzed to find the comparative responses of two antirelapse drugs , bulaquine and primaquine  , against different relapsing forms ofPlasmodium vivax infection . A 1-year follow-up study strongly suggests that the duration of preerythrocytic development ofP. vivax is a polymorphic characteristic , exhibited by two strains of hypnozoites responsible for early and late manifestations after primary infection . Short-term relapses were significantly higher in the first half year than long-term relapses , and the reverse was true in the second half year . Clinical drug response data showed that the hypnozoites characterized for short-term relapse were not susceptible to either of the antirelapse drugs in the currently administered dose , whereas hypnozoites characterized for long incubation were significantly susceptible We studied the antirelapse efficacy of a supervised 14-d 15 mg/d regimen of primaquine therapy ( n = 131 ) compared with no antirelapse therapy ( n = 142 ) in 273 patients with confirmed Plasmodium vivax malaria in Mumbai , India , between July 1998 and April 2000 . There were 6/131 ( 4.6 % ) recurrences in patients given primaquine compared with 13/142 ( 9.2 % ) in those not given antirelapse therapy . In the 14-d primaquine group , polymerase chain reaction-single str and conformational polymorphism ( PCR-SSCP ) genotyping analysis of pre- and post-treatment blood sample s was done for the 6 patients who had a recurrence of parasitaemia and the results gave a true relapse rate of 2.29 % ( 3/131 ) , 2 sample s were classified as reinfections and 1 sample did not amplify . Our results indicate probable resistance to the 14-d regimen of primaquine for the first time in India and illustrate the need to ( i ) monitor patients given this regimen and ( ii ) carry out comparative studies between primaquine and new drugs such as tafenoquine and bulaquine for preventing relapses A study conducted in 1994 showed that the use of blister packs containing antimalarial drugs significantly increased patients '  compliance , compared with traditional means of dispensing drugs in a paper envelope . The present study assessed patients ' compliance and compared the difference between 3-day chloroquine and 8-day primaquine courses of treatment for vivax malaria . The level of real compliance was determined by making the drugs with phenobarbital , and measuring its level in the blood following treatment . The results show that blister packaging significantly improved patients ' compliance ( p < 0.001 ) over traditional means of dispensing antimalarial drugs ; there was no difference in treatment compliance between 3-day and 8-day courses when the drugs were in blister packs . However , with ordinary packaging the treatment compliance rate for an 8-day course was significantly less than for a 3-day course ( P < 0.05 ) Malaria causes illness or death in unprotected travelers . Primaquine prevents malaria by attacking liver-stage parasites , a property distinguishing it from most chemoprophylactics and obviating 4-week postexposure dosing . A daily adult regimen of 30 mg primaquine prevented malaria caused by Plasmodium falciparum and P. vivax for 20 weeks in 95 of 97 glucose-6-phosphate dehydrogenase (G6PD)-normal Javanese transmigrants in Papua , Indonesia . In comparison , 37 of 149 subjects taking placebo in a parallel trial became parasitemic . The protective efficacy of primaquine against malaria was 93 % ( 95 % confidence interval [ CI ] 71%-98 % ) ; against P. falciparum it was 88 % ( 95 % CI 48%-97 % ) , and > 92 % for P. vivax ( 95 % CI > 37%-99 % ) . Primaquine was as well tolerated as placebo .  Mild methemoglobinemia ( mean of 3.4 % ) returned to normal within 2 weeks . Blood chemistry and hematological parameters revealed no evidence of toxicity . Good safety , tolerance , and efficacy , along with key advantages in dosing requirements , make primaquine an excellent drug for preventing malaria in nonpregnant , G6PD-normal travelers We conducted a study to compare the safety and tolerability of anti-relapse drugs elubaquine and primaquine against Plasmodium vivax malaria . After st and ard therapy with chloroquine , 30 mg/kg given over 3 days , 141 patients with P. vivax infection were r and omized to receive primaquine or elubaquine . The 2 treatment regimens were primaquine 30 mg once daily for 7 days ( group A , n = 71 ) , and elubaquine 25 mg once daily for 7 days ( group B , n = 70 ) . All patients cleared parasitemia within 7 days after chloroquine treatment . Among patients treated with primaquine , one patient relapsed on day 26 ; no relapse occurred with elubaquine treatement . Both drugs were well tolerated . Adverse effects occurred only in patients with G6PD deficiency who were treated with primaquine ( group A , n = 4 ) , whose mean hematocrit fell significantly on days 7 , 8 and 9 ( P = 0.015 , 0.027 , and 0.048 , respectively ) . No significant change in hematocrit was observed in patients with G6PD deficiency who were treated with elubaquine ( group B , n = 3 ) or in patients with normal G6PD . In conclusion , elubaquine , as anti-relapse therapy for P. vivax malaria , was as safe and well tolerated as primaquine and did not cause clinical ly significant hemolysis Vivax malaria accounts for 80 % of malaria cases in Mumbai ( Bombay ) and has high morbidity . In India , the st and ard treatment to prevent relapses of vivax malaria is a 5-day regimen of primaquine . However , between 1977 and 1997 , the efficacy of this treatment declined from approximately 99 % to 87 % . The efficacy of the 5-day regimen was therefore compared with that of the 14-day regimen currently recommended by the World Health Organization , in Mumbai . The relapse rates observed , over a 6-month period of follow-up , were 0 % with the 14-day regimen , 26.7 % with the 5-day , and 11.7 % when no primaquine treatment was given . The expenditure incurred on the door-to-door dispensing of the 5-day regimen appears to be without benefit . There is an urgent need to review the present strategy for controlling relapses in vivax malaria , at least for the city of Mumbai , and similar studies need to be carried out in other parts of India , to make all anti-relapse strategies more appropriate BACKGROUND Tafenoquine is an 8-aminoquinoline developed as a more effective replacement for primaquine . In a previous dose-ranging study in Thail and , 3 tafenoquine regimens with total doses ranging from 500 mg to 3000 mg prevented relapse of Plasmodium vivax malaria in most patients when administered 2 days after receipt of a blood schizonticidal dose of chloroquine . METHODS To improve convenience and to begin comparison of tafenoquine with primaquine , 80 patients with P. vivax infection were r and omized to receive 1 of the following 5 treatments 1 day after receiving a blood schizonticidal dose of chloroquine : ( A ) tafenoquine , 300 mg per day for 7 days ( n=18 ) ; ( B ) tafenoquine , 600 mg per day for 3 days ( n=19 ) ; ( C ) tafenoquine , 600 mg as a single dose ( n=18 ) ; ( D ) no further treatment ( n=13 ) ; or ( E ) primaquine base , 15 mg per day for 14 days ( n=12 ) . The minimum duration of protocol follow-up was 8 weeks , with additional follow-up to 24 weeks . RESULTS Forty-six of 55 tafenoquine recipients , 10 of 13 recipients of chloroquine only , and 12 of 12 recipients of chloroquine plus primaquine completed at least 8 weeks of follow-up ( or had relapse ) . There was 1 relapse among recipients of chloroquine plus tafenoquine , 8 among recipients of chloroquine only , and 3 among recipients of chloroquine plus primaquine . The rate of protective efficacy ( determined on the basis of reduction in incidence density ) for all recipients of chloroquine plus tafenoquine , compared with recipients of chloroquine plus primaquine , was 92.6 % ( 95 % confidence interval , 7.3%-99.9 % ; P=.042 , by Fisher 's exact test ) . CONCLUSIONS Tafenoquine doses as low as a single 600-mg dose may be useful for prevention of relapse of P. vivax malaria in Thail and For over 4 decades the antimalarial program in India has been prescribing a 5-day primaquine regimen as an antirelapse therapy to treat Plasmodium vivax malaria . In view of conflicting reports on the effectiveness of this regimen in the Indian subcontinent , and the varying prevalence of P. vivax in various ecosystems in India , the antirelapse efficacy of this regimen was evaluated in Orissa , a malaria endemic state in eastern India where P. falciparum predominates . In 723 cases of P. vivax infection treated with chloroquine alone and followed up weekly for 1 yr , the prevalence of recurrence of parasitaemia with fever was 8.6 % . Among another 759 P. vivax cases treated with chloroquine and a 5-day regimen of primaquine at 15 mg/day ( adult dose ) , the recurrence of infection was 6.5 % . The difference in recurrence was not significant ( P = 0.53 ) . It is important to note that in a great majority of cases of P. vivax in this area , infection did not recur even without treatment with primaquine . This finding , that the use of the 5-day primaquine regimen with chloroquine had no significant advantage over the use of chloroquine alone , undermines the rationale of using primaquine as an antirelapse drug in forested areas with a high prevalence of P. falciparum Chloroquine has been the st and ard treatment for Plasmodium vivax malaria for more than 40 years in most regions of the world . Recently , however , chloroquine-resistant P. vivax has been reported from Oceania , several parts of Asia , and South America . In order to assess the situation in Thail and , 886 patients with vivax malaria who were admitted to the Bangkok Hospital for Tropical Diseases from 1992 to 1997 were followed prospect ively . Most of the patients had been infected on the western border of Thail and and were experiencing their first malarial infection when admitted . All received oral chloroquine ( approximately 25 mg base/kg body weight , administered over 3 days ) and then were r and omized to receive primaquine ( 15 mg daily for 14 days ) or no further treatment . All the patients were initially responsive to chloroquine , clearing their parasitaemias within 7 days , and there were no significant differences in the clinical or parasitological responses between those treated with primaquine and those given no further treatment . Plasmodium vivax parasitaemias re-appeared within 28 days of chloroquine treatment in just four patients . In each of these four cases , re-treatment with the same regimen of chloroquine result ed in eradication of the parasitaemia , with no further appearance of parasitaemia during the next , 28-day , follow-up period . These data indicate that virtually all acute ( i.e. blood-stage ) P. vivax infections acquired in Thail and can still be successfully treated with chloroquine OBJECTIVES : In the treatment of vivax malaria , an important factor affecting the occurrence of relapse is the duration of treatment . In Belém , a number of patients with vivax malaria were found to be cured despite failure to complete the st and ard course of treatment . In Belém , a number of patients with vivax malaria were found to be cured despite failure to complete the st and ard course of treatment . This observation suggested the present study , investigating more practicable courses of treatment for children with vivax malaria . METHODS : A r and omized prospect i ve clinical trial was conducted in 200 outpatient children with vivax malaria .  Parasite clearance time and response to four therapeutic schedules were investigated : a ) chloroquine * , 10 mg/kg in a single dose ( chloroquine SD ) + primaquine , 0.50 mg/kg/dose for 7 days ; b ) chloroquine SD + primaquine , 0.25 mg/kg/dose for 7 days ; c ) chloroquine SD + primaquine , 0.50 mg/kg/dose for 5 days ; d ) chloroquine SD + primaquine , 0.25 mg/kg/dose for 5 days . Fisherśs Exact test was used to compare the responses to the schedules . RESULTS : All 144 children who completed the study had clearance of asexual parasitem 
    Output:
    
AUTHORS ' CONCLUSIONS Primaquine ( 15 mg/kg/day for 14 days ) plus chloroquine is more effective than chloroquine alone or primaquine ( 15 mg/kg for 5 days ) plus chloroquine in preventing relapses of vivax malaria .
Primaquine ( five days ) plus chloroquine appears no better than chloroquine .