Raul Chuquiyauri

Understanding the dynamics of malaria transmission in diverse endemic settings is key for designing and implementing locally adapted and sustainable control and elimination strategies. A parasitological and epidemiological survey was conducted in September–October 2012, as a baseline underlying a 3-year population-based longitudinal cohort study. The aim was to characterize malaria transmission patterns in two contrasting ecological rural sites in the Peruvian Amazon, Lupuna (LUP), a riverine environment, and Cahuide (CAH), associated with road-linked deforestation. After a full population census, 1941 individuals 3 years and older (829 in LUP, 1112 in CAH) were interviewed, clinically examined and had a blood sample taken for the detection of malaria parasites by microscopy and PCR. Species-specific parasite prevalence was estimated overall and by site. Multivariate logistic regression models assessed risk factors for parasite infection by PCR, while SaTScan detected spatial clusters of PCR-positive individuals within each site. In addition, data from routine malaria surveillance in the period 2009–2012 were obtained. Parasite prevalence by PCR was higher in CAH than in LUP for Plasmodium vivax (6.2% vs. 3.9%) and for Plasmodium falciparum (2.6% vs. 1.2%). Among PCR-confirmed infections, asymptomatic (Asy) parasite carriers were always more common than symptomatic (Sy) infections for P. vivax (Asy/Sy ratio: 2/1 in LUP and 3.7/1 in CAH) and for P. falciparum (Asy/Sy ratio: 1.3/1 in LUP and 4/1 in CAH). Sub-patent (Spat) infections also predominated over patent (Pat) infections for both species: P. vivax (Spat/Pat ratio: 2.8/1 in LUP and 3.7/1 in CAH) and P. falciparum malaria (Spat/Pat ratio: 1.9/1 in LUP and 26/0 in CAH). For CAH, age, gender and living in a household without electricity were significantly associated with P. vivax infection, while only age and living in a household with electricity was associated with P. falciparum infection. For LUP, only household overcrowding was associated with P. falciparum infection. The spatial analysis only identified well-defined clusters of P. vivax and P. falciparum infected individuals in CAH. Reported malaria incidence indicated that malaria transmission has long occurred in LUP with primarily seasonal patterns, and confirmed a malaria outbreak in CAH since May 2012. This parasitological and epidemiological baseline assessment demonstrates that malaria transmission and parasite prevalence is heterogeneous in the Peruvian Amazon, and influenced by local socio-demographics and ecological contexts. Riverine and road construction/deforestation contexts must be taken into account in order to carry out effective anti-malaria control and elimination efforts.

Infection of mosquitoes by humans is not always successful in the setting of patent gametocytemia. This study tested the hypothesis that pro- or anti-inflammatory cytokines are associated with transmission of Plasmodium vivax to Anopheles darlingi mosquitoes in experimental infection. Blood from adults with acute, non-severe P. vivax malaria was fed to laboratory-reared F1 An. darlingi mosquitoes. A panel of cytokines at the time of mosquito infection was assessed in patient sera and levels compared among subjects who did and did not infect mosquitoes. Overall, blood from 43 of 99 (43%) subjects led to mosquito infection as shown by oocyst counts. Levels of IL-10, IL-6, TNF-α, and IFN-γ were significantly elevated in vivax infection and normalized 3 weeks later. The anti-inflammatory cytokine IL-10 was significantly higher in nontransmitters compared with top transmitters but was not in TNF-α and IFN-γ. The IL-10 elevation during acute malaria was associated with P. vivax transmission blocking.

Objetivos: Describir las características clínico-epidemiológicas y la mortalidad de pacientes hospitalizados con tuberculosis (TBC) en el Departamento de Enfermedades Infecciosas, Tropicales y Dermatológicas del Hospital Nacional Cayetano Heredia (DEITD-HNCH) de Lima, Perú. Material y Métodos: Estudio retrospectivo y observacional que incluyó a pacientes hospitalizados desde enero de 1990 hasta diciembre de 2000 con diagnóstico de TBC definitiva o probable. Resultados: Se registraron 1340 altas con diagnóstico de TBC (18.7 %). La edad promedio de los pacientes hospitalizados con TBC fue 33.5 ± 15.1 años, 69.2% fueron varones y 28.1 % tuvieron infección por el Virus de la Inmunodeficiencia Humana (VIH). La mortalidad por TBC fue 17.2 % y permaneció constante durante el período. El número de muertes por TBC (230 pacientes) representó el 37.5 % de las muertes por todas las causas (613 pacientes). De los fallecidos por TBC, 151 (65.6 %) tuvieron TBC multisistémica, 60 (26.1 %) TBC pulmonar y 19 (8.3 %) TBC extrapulmonar exclusiva. Hubo sospecha clínica de TBC multidrogorresistente (TBC-MDR) en 51 (22.2 %) pacientes fallecidos. Edad mayor de 30 años (OR=1.6, 1.2Conclusiones: Tuberculosis representó el 18.7% del total de diagnósticos y el 37.5% de las muertes por todas las causas. La mortalidad relacionada con TBC en la unidad de enfermedades infecciosas de un hospital público referencial no ha disminuido en los últimos 11 años. Infección por VIH y ser mayor de 30 años están asociados a mortalidad.