RESUMEN

In the Peruvian North Coast (PNC), the number of Plasmodium vivax malaria cases increased steadily from 2007 to 2010 despite a significant decline in the overall number of cases in Peru during the same period. To better understand the transmission dynamics of P. vivax populations in the PNC and the neighboring Ecuadorian Amazon Basin (EAB), we studied the genetic variability and population structure of P. vivax in these areas. One hundred and twenty P. vivax isolates (58 from Piura and 37 from Tumbes in the PNC collected from 2008 to 2010 and 25 from the EAB collected in Pastaza from 2001 to 2004) were assessed by five polymorphic microsatellite markers. Genetic variability was determined by expected heterozygosity (He) and population structure by Bayesian inference cluster analysis. We found very low genetic diversity in the PNC (He = 0-0.32) but high genetic diversity in the EAB (He = 0.43-0.70). Population structure analysis revealed three distinct populations in the three locations. Six of 37 (16%) isolates from Tumbes had an identical haplotype to that found in Piura, suggesting unidirectional flow from Piura to Tumbes. In addition, one haplotype from Tumbes showed similarity to a haplotype found in Pastaza, suggesting that this could be an imported case from EAB. These findings strongly suggest a minimal population flow and different levels of genetic variability between these two areas divided by the Andes Mountains. This work presents molecular markers that could be used to increase our understanding of regional malaria transmission dynamics, which has implications for the development of strategies for P. vivax control.

Asunto(s)

ADN Protozoario/genética , Flujo Génico , Variación Genética , Malaria Vivax/epidemiología , Plasmodium vivax/genética , Teorema de Bayes , Ecuador/epidemiología , Haplotipos , Humanos , Malaria Vivax/diagnóstico , Malaria Vivax/parasitología , Repeticiones de Microsatélite , Perú/epidemiología , Filogeografía , Plasmodium vivax/clasificación

RESUMEN

Military personnel deployed to the Amazon Basin are at high risk for cutaneous leishmaniasis (CL). We responded to an outbreak among Peruvian Army personnel returning from short-term training in the Amazon, conducting active case detection, lesion sample collection, and risk factor assessment. The attack rate was 25% (76/303); the incubation period was 2-36 weeks (median = 8). Most cases had one lesion (66%), primarily ulcerative (49%), and in the legs (57%). Real-time polymerase chain reaction (PCR) identified Leishmania (Viannia) braziliensis (59/61 = 97%) and L. (V.) guyanensis (2/61 = 3%). Being male (risk ratio [RR] = 4.01; P = 0.034), not wearing long-sleeve clothes (RR = 1.71; P = 0.005), and sleeping in open rooms (RR = 1.80; P = 0.009) were associated with CL. Sodium stibogluconate therapy had a 41% cure rate, less than previously reported in Peru (~70%; P < 0.001). After emphasizing pre-deployment education and other basic prevention measures, trainees in the following year had lower incidence (1/278 = 0.4%; P < 0.001). Basic prevention can reduce CL risk in deployed militaries.

Asunto(s)

Brotes de Enfermedades , Leishmania braziliensis/aislamiento & purificación , Leishmaniasis Cutánea/epidemiología , Personal Militar , Adolescente , Gluconato de Sodio Antimonio/uso terapéutico , Femenino , Humanos , Leishmania guyanensis/aislamiento & purificación , Leishmaniasis Cutánea/tratamiento farmacológico , Masculino , Perú/epidemiología , Reacción en Cadena en Tiempo Real de la Polimerasa , Encuestas y Cuestionarios , Adulto Joven

RESUMEN

Much debate exists regarding the need, acceptability, and value of humanitarian medical assistance. We conducted a cross-sectional study on 457 children under 5 years from four remote riverine communities in the Peruvian Amazon and collected anthropometric measures, blood samples (1-4 years), and stool samples. Focus groups and key informant interviews assessed perspectives regarding medical aid delivered by foreigners. The prevalence of stunting, anemia, and intestinal parasites was 20%, 37%, and 62%, respectively. Infection with multiple parasites, usually geohelminths, was detected in 41% of children. The prevalence of intestinal parasites both individual and polyparasitism increased with age. Participants from smaller communities less exposed to foreigners expressed lack of trust and fear of them. However, participants from all communities were positive about foreigners visiting to provide health support. Prevalent health needs such as parasitic infections and anemia may be addressed by short-term medical interventions. There is a perceived openness to and acceptability of medical assistance delivered by foreign personnel.

Asunto(s)

Necesidades y Demandas de Servicios de Salud , Misiones Médicas , Aceptación de la Atención de Salud , Factores de Edad , Trastornos de la Nutrición del Niño/epidemiología , Preescolar , Coinfección , Femenino , Estado de Salud , Humanos , Lactante , Parasitosis Intestinales/epidemiología , Malaria/epidemiología , Masculino , Enfermedades Parasitarias/epidemiología , Perú/epidemiología , Ríos , Población Rural/estadística & datos numéricos

RESUMEN

We evaluated the efficacy of three primaquine (PQ) regimes to prevent relapses with Plasmodium vivax through an open-label randomized trial in Loreto, Peru. Vivax monoinfections were treated with chloroquine for 3 days and PQ in three different regimes: 0.5 mg/kg per day for 5 days (150 mg total), 0.5 mg/kg per day for 7 days (210 mg total), or 0.25 mg/kg per day for 14 days (210 mg total). Biweekly fever assessments and bimonthly thick smears were taken for 210 days. Recurrences after 35 days were considered relapses. One hundred eighty cases were enrolled in each group; 90% of cases completed follow-up. There were no group-related differences in age, sex, or parasitemia. Relapse rates were similar in the 7- and 14-day regimes (16/156 = 10.3% and 22/162 = 13.6%, P = 0.361) and higher in the 5-day group (48/169 = 28.4%, P < 0.001 and P = 0.001, respectively). The 7-day PQ regimen used in Peru is as efficacious as the recommended 14-day regimen and superior to 5 treatment days.

Asunto(s)

Antimaláricos/farmacología , Cloroquina/farmacología , Malaria Vivax/tratamiento farmacológico , Primaquina/farmacología , Adolescente , Adulto , Anciano , Niño , Preescolar , Esquema de Medicación , Quimioterapia Combinada , Femenino , Humanos , Malaria Vivax/parasitología , Masculino , Persona de Mediana Edad , Perú , Plasmodium vivax/fisiología , Recurrencia , Resultado del Tratamiento

RESUMEN

Severe malaria caused by Plasmodium vivax is no longer considered rare. To describe its clinical features, we performed a retrospective case control study in the subregion of Luciano Castillo Colonna, Piura, Peru, an area with nearly exclusive vivax malaria transmission. Severe cases and the subset of critically ill cases were compared with a random set of uncomplicated malaria cases (1:4). Between 2008 and 2009, 6,502 malaria cases were reported, including 106 hospitalized cases, 81 of which fit the World Health Organization definition for severe malaria. Of these 81 individuals, 28 individuals were critically ill (0.4%, 95% confidence interval = 0.2-0.6%) with severe anemia (57%), shock (25%), lung injury (21%), acute renal failure (14%), or cerebral malaria (11%). Two potentially malaria-related deaths occurred. Compared with uncomplicated cases, individuals critically ill were older (38 versus 26 years old, P < 0.001), but similar in other regards. Severe vivax malaria monoinfection with critical illness is more common than previously thought.

Asunto(s)

Anemia/patología , Hospitalización/estadística & datos numéricos , Lesión Pulmonar/patología , Malaria Vivax/patología , Insuficiencia Renal Crónica/patología , Choque/patología , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Anemia/diagnóstico , Anemia/etiología , Anemia/parasitología , Encéfalo/parasitología , Encéfalo/patología , Estudios de Casos y Controles , Preescolar , Enfermedad Crítica , Enfermedades Endémicas , Femenino , Humanos , Lesión Pulmonar/diagnóstico , Lesión Pulmonar/etiología , Lesión Pulmonar/parasitología , Malaria Vivax/complicaciones , Malaria Vivax/diagnóstico , Malaria Vivax/parasitología , Masculino , Persona de Mediana Edad , Perú , Plasmodium vivax/patogenicidad , Insuficiencia Renal Crónica/diagnóstico , Insuficiencia Renal Crónica/etiología , Insuficiencia Renal Crónica/parasitología , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Choque/diagnóstico , Choque/etiología , Choque/parasitología

RESUMEN

BACKGROUND: Plasmodium vivax is a predominant species of malaria in parts of South America and there is increasing resistance to drugs to treat infections by P. vivax. The existence of latent hypnozoites further complicates the ability to classify recurrent infections as treatment failures due to relapse, recrudescence of hyponozoites or re-infections. Antigen loci are putatively under natural selection and may not be an optimal molecular marker to define parasite haplotypes in paired samples. Putatively neutral microsatellite loci, however, offer an assessment of neutral haplotypes. The objective here was to assess the utility of neutral microsatellite loci to reconcile cases of recurrent parasitaemia in Amazonian P. vivax populations in Peru. METHODS: Patient blood samples were collected from three locations in or around Iquitos in the Peruvian Amazon. Five putatively neutral microsatellite loci were characterized from 445 samples to ascertain the within and amongst population variation. A total of 30 day 0 and day of recurrent parasitaemia samples were characterized at microsatellite loci and five polymorphic antigen loci for haplotype classification. RESULTS: The genetic diversity at microsatellite loci was consistent with neutral levels of variation measured in other South American P. vivax populations. Results between antigen and microsatellite loci for the 30 day 0 and day of recurrent parasitaemia samples were the same for 80% of the pairs. The majority of non-concordant results were the result of differing alleles at microsatellite loci. This analysis estimates that 90% of the paired samples with the same microsatellite haplotype are unlikely to be due to a new infection. CONCLUSIONS: A population-level approach was used to yield a better estimate of the probability of a new infection versus relapse or recrudescence of homologous hypnozoites; hypnozoite activation was common for this cohort. Population studies are critical with the evaluation of genetic markers to assess P. vivax biology and epidemiology. The additional demonstration of microsatellite loci as neutral markers capable of distinguishing the origin of the recurrent parasites (new infection or originating from the patient) lends support to their use in assessment of treatment outcomes.

Asunto(s)

Variación Genética , Malaria Vivax/epidemiología , Malaria Vivax/parasitología , Parasitemia/epidemiología , Parasitemia/parasitología , Plasmodium vivax/clasificación , Plasmodium vivax/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , ADN Protozoario/genética , Femenino , Haplotipos , Humanos , Lactante , Masculino , Repeticiones de Microsatélite , Persona de Mediana Edad , Perú/epidemiología , Recurrencia , Adulto Joven

RESUMEN

Non-treponemal tests such as the rapid plasma reagin (RPR) assay are mainstays of syphilis diagnosis, but false-positive tests are common. We identified false-positive RPR titers in 8.2% of patients with malaria due to Plasmodium vivax in northern Peru. Similar rates were not detected in patients with other acute febrile illnesses.

Asunto(s)

Fiebre de Origen Desconocido/etiología , Malaria Vivax/diagnóstico , Plasmodium vivax/aislamiento & purificación , Reaginas/sangre , Sífilis/complicaciones , Enfermedad Aguda , Adulto , Estudios de Casos y Controles , Demografía , Reacciones Falso Positivas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Perú , Serodiagnóstico de la Sífilis , Factores de Tiempo , Adulto Joven

RESUMEN

Domestic farm animals (n=145) were sampled for the presence of ectoparasites in northwestern Peru during March, 2008. Ninety domestic animals (62%) were positive for the presence of an ectoparasite(s) and produced a total collection of the following: 728 ticks [Amblyomma maculatum, Anocentor nitens, Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus, and Otobius megnini], 12 lice (Haematopinus suis), and 3 fleas (Ctenocephalides felis). A Rickettsia genus-specific qPCR assay was performed on nucleic acid preparations of the collected ectoparasites that resulted in 5% (37/743, 35 ticks and 2 fleas) of the ectoparasites positive for the presence of Rickettsia. DNA from the positive individual ticks was tested with 2 other qPCR assays for the presence of the ompB gene in Candidatus Rickettsia andeanae or Rickettsia parkeri. Candidatus R. andeanae was found in 25 A. maculatum ticks and in two Rh. sanguineus ticks, whereas R. parkeri was detected in 6 A. maculatum ticks. Two A. maculatum were co-infected with both Candidatus R. andeanae and R. parkeri. Rickettsia felis was detected in 2 fleas, Ctenocephalides felis, by multilocus sequence typing of the 17-kD antigen and ompA genes. These findings expand the geographic range of R. parkeri to include Peru as well as expand the natural arthropod vector of Candidatus R. andeanae to include Rhipicephalus sanguineus.

Asunto(s)

Vectores Artrópodos/microbiología , Ctenocephalides/microbiología , Infestaciones Ectoparasitarias/veterinaria , Phthiraptera/microbiología , Infecciones por Rickettsia/veterinaria , Rickettsia/aislamiento & purificación , Garrapatas/microbiología , Animales , Animales Domésticos , Proteínas Bacterianas/genética , ADN Bacteriano/genética , Infestaciones Ectoparasitarias/parasitología , Infestaciones por Pulgas/parasitología , Infestaciones por Pulgas/veterinaria , Infestaciones por Piojos/parasitología , Infestaciones por Piojos/veterinaria , Tipificación de Secuencias Multilocus/veterinaria , Perú/epidemiología , Reacción en Cadena de la Polimerasa/veterinaria , Rhipicephalus sanguineus/microbiología , Rickettsia/genética , Infecciones por Rickettsia/epidemiología , Infecciones por Rickettsia/microbiología , Análisis de Secuencia de ADN/veterinaria , Infestaciones por Garrapatas/parasitología , Infestaciones por Garrapatas/veterinaria

RESUMEN

In South America, various species of Leishmania are endemic and cause New World tegumentary leishmaniasis (NWTL). The correct identification of these species is critical for adequate clinical management and surveillance activities. We developed a real-time polymerase chain reaction (PCR) assay and evaluated its diagnostic performance using 64 archived parasite isolates and 192 prospectively identified samples collected from individuals with suspected leishmaniasis enrolled at two reference clinics in Lima, Peru. The real-time PCR assay was able to detect a single parasite and provided unambiguous melting peaks for five Leishmania species of the Viannia subgenus that are highly prevalent in South America: L. (V.) braziliensis, L. (V.) panamensis, L. (V.) guyanensis, L. (V.) peruviana and L. (V.) lainsoni. Using kinetoplastid DNA-based PCR as a gold standard, the real-time PCR had sensitivity and specificity values of 92% and 77%, respectively, which were significantly higher than those of conventional tests such as microscopy, culture and the leishmanin skin test (LST). In addition, the real-time PCR identified 147 different clinical samples at the species level, providing an overall agreement of 100% when compared to multilocus sequence typing (MLST) data performed on a subset of these samples. Furthermore, the real-time PCR was three times faster and five times less expensive when compared to PCR - MLST for species identification from clinical specimens. In summary, this new assay represents a cost-effective and reliable alternative for the identification of the main species causing NWTL in South America.

Asunto(s)

Leishmania/aislamiento & purificación , Leishmaniasis Cutánea/diagnóstico , Leishmaniasis Cutánea/parasitología , Técnicas de Diagnóstico Molecular/métodos , Parasitología/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , ADN de Cinetoplasto/genética , ADN Protozoario/genética , Humanos , Leishmania/clasificación , Leishmania/genética , Perú , Sensibilidad y Especificidad , Factores de Tiempo

RESUMEN

Leishmania species of the Viannia subgenus are responsible for most cases of New World tegumentary leishmaniasis. However, little is known about the vectors involved in disease transmission in the Amazon regions of Peru. We used a novel real-time polymerase chain reaction (PCR) to assess Leishmania infections in phlebotomines collected in rural areas of Madre de Dios, Peru. A total of 1,299 non-blood fed female sand flies from 33 species were captured by using miniature CDC light traps. Lutzomyia auraensis was the most abundant species (63%) in this area. Seven of 164 pools were positive by PCR for Leishmania by kinetoplast DNA. The real-time PCR identified four Lu. auraensis pools as positive for L. (Viannia) lainsoni and L. (V.) braziliensis. The minimum infection prevalence for Lu. auraensis was estimated to be 0.6% (95% confidence interval = 0.20-1.42%). Further studies are needed to assess the importance of Lu. auraensis in the transmission of New World tegumentary leishmaniasis in hyperendemic areas of Peru.

Asunto(s)

ADN de Cinetoplasto/aislamiento & purificación , Transferencia Resonante de Energía de Fluorescencia/métodos , Insectos Vectores/parasitología , Leishmaniasis/epidemiología , Psychodidae/parasitología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Animales , ADN de Cinetoplasto/genética , Femenino , Leishmania/clasificación , Leishmania/genética , Leishmania/aislamiento & purificación , Leishmania/patogenicidad , Leishmaniasis/transmisión , Masculino , Perú/epidemiología

RESUMEN

The widespread use of primaquine (PQ) and chloroquine (CQ), together, may be responsible for the relatively few, isolated cases of chloroquine-resistant P. vivax (CQRPV) that have been reported from South America. We report here a case of P. vivax from the Amazon Basin of Peru that recurred against normally therapeutic blood levels of CQ. Four out of 540 patients treated with combination CQ and PQ had a symptomatic recurrence of P. vivax parasitemia within 35 days of treatment initiation, possibly indicating CQ failure. Whole blood total CQ level for one of these four subjects was 95 ng/ml on the day of recurrence. Based on published criteria that delineate CQRPV as a P. vivax parasitemia, either recrudescence or relapse, that appears against CQ blood levels >100 ng/mL, we document the occurrence of a P. vivax strain in Peru that had unusually high tolerance to the synergistic combination therapy of CQ + PQ that normally works quite well.