Background Since the World Health Organization recommended single low-dose (0.25mg/kg) primaquine (PQ) in combination with artemisinin-based combination therapies (ACTs) in areas of low transmission or artemisinin-resistant P. falciparum, several single-site studies have been conducted to assess its efficacy. Methods An individual patient meta-analysis to assess the gametocytocidal and transmission-blocking efficacy of PQ used in combination with different ACTs was conducted. Random effects logistic regression was used to quantify PQ effect on (i) gametocyte carriage in the first two weeks post-treatment; (ii) the probability of infecting at least one mosquito or of a mosquito becoming infected. Results In 2,574 participants from fourteen studies, PQ reduced PCR-determined gametocyte carriage on days 7 and 14, most apparently in patients presenting with gametocytaemia on day 0 (Odds Ratio (OR)=0.22; 95%CI 0.17-0.28 and OR=0.12; 95%CI 0.08–0.16, respectively). The rate of decline in gametocyte carriage was faster when PQ was combined with artemether-lumefantrine (AL) compared to dihydroartemisinin-piperaquine (DP) (p=0.010 for day 7). Addition of 0.25mg/kg PQ was associated with near complete prevention of transmission to mosquitoes. Conclusion Primaquine’s transmission-blocking effects are achieved with 0.25 mg/kg PQ. Gametocyte persistence and infectivity are lower when PQ is combined with AL compared to DP.

Treatment against malaria includes blood schizonticides to clear asexual parasites responsible for disease. The addition of gametocytocidal drugs can eliminate infectious sexual stages with potential for transmission and the World Health Organization recommends a single dose (SD) of primaquine (PQ) to this end. The efficacy of PQ at 0.75 mg/kg to suppress gametocytemia when administered in single or fractionated doses was evaluated. A clinical controlled study with an open-label design was executed; three groups of 20 subjects were studied sequentially. All subjects were treated with the standard dose of artemether-lumefantrine plus the total dose of 0.75 mg/kg of PQ administered (without previous G6PD testing) in three different ways: Group "0.75d-3" received 0.75 mg/kg on day 3; Group "0.50d-1 + 0.25d-3" received 0.50 mg/kg on day 1 and 0.25 mg/kg on day 3; Group "0.25d-1,2,3" received 0.25 mg/kg on days 1, 2, and 3. Subjects were evaluated on days 1, 4, and 7 by thick smear microscopy and quantitative polymerase chain reaction to determine the carriage of immature and mature gametocytes. There were no adverse events. The three schemes caused a marked reduction (75-85%) in prevalence of gametocytes on day 4 compared with day 1, but only the group that received 0.75 mg/kg on day 3 maintained the reduced gametocyte burden until day 7. None of the three treatments were able to clear gametocyte carriage on days 4 or 7, but the group that received the SD had the lowest prevalence of gametocytes (15%). Further studies are needed to establish a PQ regimen with complete efficacy against gametocytes.

En muchos países la fasciolosis y paramfistomosis representan un grave problema para la salud del sector pecuario. En Colombia hay registros de ambas distomatosis en bovinos, de la mayoría del trópico alto andino, las cuales generan pérdidas económicas anuales cercanas a 40 000 000 000 COP. El objetivo de esta investigación fue determinar la prevalencia de fasciolosis y paramfistomosis en vacunos de la hacienda La Candelaria, Caucasia (Colombia), y la presencia de caracoles hospederos intermediarios. Para cumplirlo, se realizó un estudio descriptivo de corte transversal con muestreo no probabilístico por conveniencia. Se recolectaron heces de los animales y se hizo el diagnóstico mediante la técnica modificada de Dennis. Se establecieron las prevalencias de los digeneos de acuerdo con el sexo, peso, edad y raza. Se recolectaron caracoles dulciacuícolas en la zona estudiada y se identificaron por morfología. Se analizaron 466 muestras fecales de 178 bovinos, de las razas Cebú (Bos indicus), BON (blanco orejinegro) y del cruce entre ellas. Se diagnosticaron F. hepatica y Paramphistomidae con prevalencias del 2,2% y 30,9%, respectivamente. En el 1,1% de los vacunos se diagnosticó coinfección. Ambas trematodosis prevalecieron en las hembras (p = 0,03). Se identificaron moluscos dulciacuícolas Ampullariidae, Physidae y Planorbidae sin estadios larvarios de digeneos. Se concluyó que los bovinos de doble propósito de la hacienda La Candelaria están expuestos a F. hepatica y Paramphistomidae, y, probablemente, se infectan en los predios de la hacienda. Paramphistomidae es más prevalente que F. hepatica, lo cual concuerda con lo descrito en algunos estudios