Plasmodium vivax resistance to chloroquine (R2) and mefloquine (R3) in Brazilian Amazon region

Abstract

Maria das Graças C. Alecrim, Wilson Alecrim and Vanize MacêdoResistência do Plasmodium vivax pela cloroquina (R2) e mefloquina (R3) na amazônia BrasileiraWe report for the first time R2 resistance to chloroquine and R3 resistance to mefloquine by P. vivax in the Brazilian Amazon region.FSS, a 12 year-old female patient from Autazes Municipality in the State of Amazonas, Brazil, was diagnosed as having P. vivax malaria on July 14 th 1997 (day 0) at the Instituto de Medicina Tropical do Amazonas, Manaus, Brazil. Day 0 parasitemia was 250 parasites/µl. The patient was treated with 10 mg/kg body weight oral chloroquine on the first day and 7.5mg/kg on the second and third days. On day 4 parasitemia was 500/µl. On day 7 blood was negative. On day 9 parasitemia was 1,000/µl when we treated her with 20mg/kg mefloquine. On day 19 parasitemia was 3,000/µl. She was treated again with the same chloroquine dosage in a directly observed schedule. On day 3 of the last scheme parasitemia was 3,100/µl.On day 5 parasitemia decreased to 500/µl and increased to 800/µl on day 7, showing the R2 pattern of P. vivax chloroquine resistance.The patient remained stable despite the level of parasitemia that increased to 1,720 on day 10. She was then treated with a supervised dose of 20mg/kg mefloquine. Parasitemia decreased to 258/µl on day 3 and increased to 4,472/µl on day 7, showing the R3 pattern of P. vivax resistance

Plasmodium vivax Chloroquine Resistance and Anemia in the Western Brazilian Amazon

“…In Brazil, the first clinical evidence was reported in 2000 in Manaus (13). In Colombia, P. vivax CR was described in three cases among 27 subjects (14), and in Peru four cases were confirmed among 177 subjects (15).…”

Eficacia de la combinación amodiaquina más sulfadoxinapirimetamina y de la cloroquina para el tratamiento del paludismo en Córdoba, Colombia, 2006

“…Los hallazgos enfatizan la importancia de diseñar estrategias para asegurar y vigilar el cumplimiento terapéutico, con el fin de garantizar la eficacia del tratamiento antipalúdico, cuando el medicamento se entrega a los pacientes con paludismo en los puestos de diagnóstico y tratamiento que son atendidos en su mayoría por microscopistas. A pesar de algunos informes de fallas terapéuticas en Guyana y Brasil (19,20), los resultados de los estudios de eficacia in vivo realizados hasta la fecha en Perú y Colombia (11,21,22,24,25) demuestran, en general, la eficacia de la cloroquina para el tratamiento del paludismo por P. vivax, a diferencia de lo informado en Papua, Nueva Guinea (17), y en Indonesia (18). De acuerdo con estos hallazgos, la resistencia de P. vivax a la cloroquina no constituye aún un serio problema en las Américas, aunque sí parece ser un problema emergente en la cuenca amazónica (15,19,20), mas no en las demás áreas endémicas de transmisión de paludismo en Colombia.…”

“…En las Américas, se han informado casos de fallas terapéuticas en Guyana (19) y Brasil (20). En un estudio realizado en Perú entre 1998 y 2001, con seguimiento de 28 días, se reportaron fallas en 4 de 177 pacientes (2,26%) con paludismo por P. vivax tratados con cloroquina en la región amazónica y ninguna falla en 59 pacientes evaluados al norte de la costa del Pacífico peruano (21).…”

Malaria in the State of Amazonas: a typical Brazilian tropical disease influenced by waves of economic development

“…Some national studies have indicated the need for novel therapeutic strategies to circumvent the problem of chloroquine resistance for the treatment of P. vivax malaria, which is estimated at 5-10% in Manaus (34) (35) . It is possible that, in the short term, we may have to make use of artemisinin-based combination therapies (ACTs) as the fi rst choice in the State of Amazonas, although other states have not reported cases of chloroquine resistance, which is expected in large areas such as the Brazilian Amazon.…”