In the context of malaria elimination in the Americas, solid evidence is necessary of the
effectiveness of anti-malarial control measures delivered to the affected individuals. In the
Americas, most P. vivax infections are sensitive to Chloroquine (CQ) and Primaquine (PQ), and
the most effective treatment worldwide comprises administration of a total dose of 25
milligrams (mg)/Kilogram (kg) weight of CQ distributed in three days and 3.5 mg/kg body
weight of PQ administered during 14 days (T14). In Mexico, CQ and PQ have been administered
since the late 50´s to treat malarious patients. In 1999 the National Malaria Control Program
implemented an intermittent single doses treatment (ISD) as part of the overall strategy.
After the blood sample was obtained for diagnosis of symptomatic patients, a single combined
dose of CQ and PQ was administered, and after malaria infection confirmation, additional
doses were administered monthly alternating each three months, during 3 years. Although, the
number of malaria cases were reduced in most affected regions, in Southern México, many
patients under ISD present recurrent blood infections, presumably relapse episodes were
observed.
Working hypothesis: the administration of ISD is low effective to eliminate relapse episodes
and its effectiveness depends on the coincidence of the relapse episodes and the
administration of the medication), while the T14 is highly effective to eliminate P. vivax
primary and relapse infections.
Objective: To determine the antimalarial drug effectiveness of the ISD and T14, based on CQ
and PQ for the treatment of uncomplicated P. vivax infection (primary and recurrent blood
infections) in Southern Mexico.
Methods: The study was carried out in malaria affected communities of Southern Mexico,
following the WHO recommendations for clinical studies. Symptomatic patients diagnosed with
P. vivax infection that meet the inclusion criteria, were invited to participate. After they
accepted by informed consent, patients were semi-randomized and treated with either T14
(14-day treatment) or ISD (18 intermittent single doses of CQ-PQ). Clinical, parasitological,
molecular and serological parameters were monitor over a 12-month follow up period to
evaluate the treatment outcomes to cure blood infection and relapsing episodes. The study was
conducted from February-2007 to October-2010. The results of this study will be used to
assist the Ministry of Health of México in assessing the current national treatment
guidelines for uncomplicated P. vivax malaria
Phase:
Phase 4
Details
Lead Sponsor:
LILIA GONZALEZ CERON
Collaborators:
Centro Nacional de Vigilancia Epidemiológica y control de enfermedades (CENAVECE), Mexico Instituto de Diagnóstico y Referencia Epidemiológicos (InDRE), Mexico Jurisdicción Sanitaria VII, Chiapas, México Pan American Health Organization