Evaluation of the effectiveness of the OptiMAL-IT™ rapid test in the follow up of patients diagnosed with malaria in the Peruvian Amazon / Evaluación de la efectividad de la prueba rápida OptiMAL-IT™ para el seguimiento de pacientes con diagnóstico de malaria en la Amazonía peruana

Introduction: In Peru, optical microscopy with the thick smear test continues to be performed for the follow-up of malaria patients. This test is simple but it requires microscopic equipment and suitable staff to perform the reading of the samples. Studies suggest that the rapid OptiMAL-IT™ test is an option for follow-up. Objective: To evaluate the effectiveness of OptiMAL-IT™ as a follow-up test in malaria patients in endemic areas of Perú. Materials and methods: We conducted an observational, analytical cross-sectional study of diagnostic tests performed in patients with malaria. We selected all the patients attending different health facilities in the Peruvian departments of San Martín and Loreto who met the inclusion criteria. Optical microscopy with thick smear and OptiMAL-IT™ was used on days 2, 3, 7, and 14 for Plasmodium vivax and until day 21 of follow-up for Plasmodium falciparum. Percentages of correctly classified samples and predictive values were calculated, and the results were compared between the western jungle and the eastern jungle using Chi2 or Fisher's exact tests. Results: We registered 262 patients from San Martín and 302 from Loreto. The percentage of correctly classified cases and the negative predictive value were higher than 92.0% and 93,0%, respectively, from the third day of follow-up; no statistical differences were found in the results obtained from the western jungle and those from the eastern jungle. Conclusions: The OptiMAL-IT™ test would be effective as a follow-up test in patients diagnosed with malaria in endemic areas of Perú.

Introducción. En Perú, la microscopía óptica con gota gruesa continúa utilizándose en el seguimiento de los pacientes con malaria o paludismo. Esta prueba es sencilla, pero requiere de equipamiento microscópico y personal idóneo que realice la lectura de las muestras. Los estudios sugieren que la prueba rápida OptiMAL-IT™ es una opción para dicho seguimiento. Objetivo. Evaluar la efectividad de OptiMAL-IT™ como test de seguimiento en pacientes con malaria en áreas endémicas del Perú. Materiales y métodos. Se hizo un estudio observacional, transversal y analítico de pruebas diagnósticas en pacientes con malaria. Se seleccionó a todos los pacientes que cumplían con los criterios de inclusión, procedentes de diferentes establecimientos de salud de los departamentos peruanos de San Martín y Loreto. El diagnóstico se hizo mediante microscopía óptica con gota gruesa y la prueba rápida de diagnóstico inmunocromatográfico OptiMAL-IT™ en los días 2, 3, 7 y 14 para Plasmodium vivax y hasta el día 21 de seguimiento para Plasmodium falciparum. Se calculó el porcentaje de los correctamente clasificados y los valores predictivos, y se compararon los resultados de la selva occidental y la selva oriental mediante ji al cuadrado o prueba exacta de Fisher. Resultados. Se registraron 262 pacientes de San Martín y 302 de Loreto. Los porcentajes correctamente clasificados y el valor predictivo negativo fueron superiores a 92,0 y 93,0 %, respectivamente, a partir del tercer día de seguimiento; no se encontraron diferencias estadísticas en los resultados obtenidos en la Amazonía occidental y los de la oriental. Conclusiones. La prueba OptiMAL-IT™ sería efectiva como test de seguimiento en los pacientes con diagnóstico de malaria en áreas endémicas del Perú.

Evaluación de la efectividad de la prueba rápida OptiMAL-IT™ para el seguimiento de pacientes con diagnóstico de malaria en la Amazonía peruana / Evaluation of the effectiveness of the OptiMAL-IT™ rapid test in the follow up of patients diagnosed with malaria in the Peruvian Amazon

Introducción. En Perú, la microscopía óptica con gota gruesa continúa utilizándose en el seguimiento de los pacientes con malaria o paludismo. Esta prueba es sencilla, pero requiere de equipamiento microscópico y personal idóneo que realice la lectura de las muestras. Los estudios sugieren que la prueba rápida OptiMAL-IT™ es una opción para dicho seguimiento. Objetivo. Evaluar la efectividad de OptiMAL-IT™ como test de seguimiento en pacientes con malaria en áreas endémicas del Perú. Materiales y métodos. Se hizo un estudio observacional, transversal y analítico de pruebas diagnósticas en pacientes con malaria. Se seleccionó a todos los pacientes que cumplían con los criterios de inclusión, procedentes de diferentes establecimientos de salud de los departamentos peruanos de San Martín y Loreto. El diagnóstico se hizo mediante microscopía óptica con gota gruesa y la prueba rápida de diagnóstico inmunocromatográfico OptiMAL-IT™ en los días 2, 3, 7 y 14 para Plasmodium vivax y hasta el día 21 de seguimiento para Plasmodium falciparum. Se calculó el porcentaje de los correctamente clasificados y los valores predictivos, y se compararon los resultados de la selva occidental y la selva oriental mediante ji al cuadrado o prueba exacta de Fisher. Resultados. Se registraron 262 pacientes de San Martín y 302 de Loreto. Los porcentajes correctamente clasificados y el valor predictivo negativo fueron superiores a 92,0 y 93,0 %, respectivamente, a partir del tercer día de seguimiento; no se encontraron diferencias estadísticas en los resultados obtenidos en la Amazonía occidental y los de la oriental. Conclusiones. La prueba OptiMAL-IT™ sería efectiva como test de seguimiento en los pacientes con diagnóstico de malaria en áreas endémicas del Perú.

Introduction: In Peru, optical microscopy with the thick smear test continues to be performed for the follow-up of malaria patients. This test is simple but it requires microscopic equipment and suitable staff to perform the reading of the samples. Studies suggest that the rapid OptiMAL-IT™ test is an option for follow-up. Objective: To evaluate the effectiveness of OptiMAL-IT™ as a follow-up test in malaria patients in endemic areas of Perú. Materials and methods: We conducted an observational, analytical cross-sectional study of diagnostic tests performed in patients with malaria. We selected all the patients attending different health facilities in the Peruvian departments of San Martín and Loreto who met the inclusion criteria. Optical microscopy with thick smear and OptiMAL-IT™ was used on days 2, 3, 7, and 14 for Plasmodium vivax and until day 21 of follow-up for Plasmodium falciparum. Percentages of correctly classified samples and predictive values were calculated, and the results were compared between the western jungle and the eastern jungle using Chi2 or Fisher's exact tests. Results: We registered 262 patients from San Martín and 302 from Loreto. The percentage of correctly classified cases and the negative predictive value were higher than 92.0% and 93,0%, respectively, from the third day of follow-up; no statistical differences were found in the results obtained from the western jungle and those from the eastern jungle. Conclusions: The OptiMAL-IT™ test would be effective as a follow-up test in patients diagnosed with malaria in endemic areas of Perú.

[Maternal death from severe malaria due to Plasmodium vivax]. / Muerte materna por malaria grave por Plasmodium vivax.

Here we describe the case of a 19-year-old woman, in her 29th week of gestation, who was from Llumpe (Ancash, Peru) and had a history of traveling to Chanchamayo (Junín, Peru) and Rinconada (Ancash, Peru). The patient presented at Chacas Hospital (Chacas, Ancash, Peru) with general malaise, dehydration, respiratory distress, jaundice, the sensation of thermal rise, and abdominal pain. Analysis of blood smears revealed 60% hemoparasites. She was transferred to Ramos Guardia Hospital (Huaraz, Peru) where she presented increasing respiratory distress, choluria, hematuria, and decreased urine output, moreover she was positive for Plasmodium. From there she was transferred to Cayetano Heredia Hospital (Lima, Peru), where she was admitted to the intensive care unit (ICU) with multiple organ failure, stillbirth, and leading to death. She underwent mechanical ventilation, was administered clindamycin, and was prescribed quinine, which she did not received due a lack by availability. The evolution of the illness was torpid, and she ultimately developed multiple organ failure and died. Plasmodium vivax infection was confirmed. Accordingly, we emphasize the importance of improving our diagnostic capabilities and management techniques to enable clinicians to provide adequate and timely treatment.

Prevalence of nutritional deficiencies and morbidity by infectious diseases in children 0-5 years of age in Iñapari in the Peruvian Amazon

Introduction: Iñapari is a town located in Peru, on the border of Brazil, between the Amazonian states of Acre and Amazonas. The local Peruvian children under five years of age present moderate anemia while the percentage of chronic child malnutrition is a major public health problem in the country as a whole. Goals: The purpose of this study was to identify the prevalence of major childhood morbidities caused by anemia, malnutrition, intestinal parasites, toxocariasis, and hepatitis A, and identify connections with the socioeconomic and environmental conditions found in Iñapari. Methods: Interviews with questionnaires; anthropometric measurements, collection of feces and venous blood samples. Results: A 20% prevalence of anemia and 8.5% prevalence of chronic malnutrition (height for age deficiency) was found. A pathogenic intestinal parasite was noted in 24.5% of the samples, where Giardia intestinalis (14.7%) was the most frequent. The seroprevalence of toxocariasis was 33.8% and hepatitis A was 21.2%. Conclusion: There is a connection between the results found and the poor living and sanitary conditions of the population. The low income noted is also linked to the malnutrition and anemia detected

Prenatal care and childbirth assistance in Amazonian women before and after the Pacific Highway Construction (2003-2011): a cross-sectional study.

BACKGROUND: Attention to prenatal care and child delivery is important for the health of women and children, but in the Amazon these indicators tend to be historically unfavorable, in part by geographical and political isolation. In 2003 both Brazilian and Peru governments have finished paving an international road connecting remotes areas in the Brazilian Amazon to the Pacific coast in Peru. METHODS: The situation of prenatal care and child delivery with mothers of children under 5 years old living in the urban area of Assis Brasil, Acre was assessed in two cross-sectional studies performed in 2003 and 2011, corresponding to the period before and after the Pacific highway construction. RESULTS: In 2003, most mothers were of black/Afro-American ethnicity, or "pardos" (the offspring of a Caucasian with a African descendant) (77.69 %), had more than 4 years of schooling (73.40 %) and had a mean age of 22.18 years. In 2011, the number of as a migration of indigenous women increased from 0 to 14.40 % of the respondents, because of migration from communities along the rivers to urban areas, with no other significant changes in maternal characteristics. No significant improvement in childbirth assistance was noticed between 1997 and 2011; only the percentage of in-hospital vaginal deliveries performed by doctors increased from 17.89 to 66.26 % (p <0.001) during this period. Access to prenatal care was associated with white ethnicity in 2003, and higher socioeconomic level and white ethnicity in 2011, while the higher number of prenatal visits was associated with higher maternal education and higher socioeconomic levels in 2011. Vaginal child delivery at a hospital facility was associated with maternal age in 2003, and year of birth, being of white ethnicity and higher level of education in 2011. CONCLUSIONS: The indicators of prenatal care and child delivery were below the national average, showing that geographical isolation still affects women's health care in the Amazon, despite the construction of the highway and governmental health protocols adopted during this period.

Muerte materna por malaria grave por Plasmodium vivax / Maternal death from severe malaria due to Plasmodium vivax

RESUMEN Se presenta el caso de una mujer de 19 años con 29 semanas de gestación, procedente de Llumpe (Ancash) con antecedentes de viajes a las localidades de Chanchamayo (Junín) y Rinconada (Ancash). Ingresó al Hospital de Chacas (Ancash) por presentar mal estado general, deshidratación, dificultad respiratoria, ictericia, sensación de alza térmica y dolor abdominal, tuvo reporte de: hemoparásitos 60% en frotis sanguíneo. Fue transferida al Hospital Ramos Guardia (Huaraz) donde presentó mayor dificultad respiratoria, coluria, hematuria, disminución del débito urinario y reporte de Plasmodium (+), luego fue transferida al Hospital Cayetano Heredia (Lima) donde ingresó a la Unidad de Cuidados Intensivos (UCI), con evolución a falla multiorgánica, óbito fetal y muerte materna. Se confirmó infección por Plasmodium vivax. Destacamos la importancia de mejorar nuestras capacidades de diagnóstico y manejo para brindar un tratamiento adecuado y oportuno.

ABSTRACT Here we describe the case of a 19-year-old woman, in her 29th week of gestation, who was from Llumpe (Ancash, Peru) and had a history of traveling to Chanchamayo (Junín, Peru) and Rinconada (Ancash, Peru). The patient presented at Chacas Hospital (Chacas, Ancash, Peru) with general malaise, dehydration, respiratory distress, jaundice, the sensation of thermal rise, and abdominal pain. Analysis of blood smears revealed 60% hemoparasites. She was transferred to Ramos Guardia Hospital (Huaraz, Peru) where she presented increasing respiratory distress, choluria, hematuria, and decreased urine output, moreover she was positive for Plasmodium. From there she was transferred to Cayetano Heredia Hospital (Lima, Peru), where she was admitted to the intensive care unit (ICU) with multiple organ failure, stillbirth, and leading to death. She underwent mechanical ventilation, was administered clindamycin, and was prescribed quinine, which she did not received due a lack by availability. The evolution of the illness was torpid, and she ultimately developed multiple organ failure and died. Plasmodium vivax infection was confirmed. Accordingly, we emphasize the importance of improving our diagnostic capabilities and management techniques to enable clinicians to provide adequate and timely treatment.

Molecular Investigation into a Malaria Outbreak in Cusco, Peru: Plasmodium falciparum BV1 Lineage is Linked to a Second Outbreak in Recent Times.

In November 2013, a Plasmodium falciparum malaria outbreak of 11 cases occurred in Cusco, southern Peru, where falciparum malaria had not been reported since 1946. Although initial microscopic diagnosis reported only Plasmodium vivax infection in each of the specimens, subsequent examination by the national reference laboratory confirmed P. falciparum infection in all samples. Molecular typing of four available isolates revealed identity as the B-variant (BV1) strain that was responsible for a malaria outbreak in Tumbes, northern Peru, between 2010 and 2012. The P. falciparum BV1 strain is multidrug resistant, can escape detection by PfHRP2-based rapid diagnostic tests, and has contributed to two malaria outbreaks in Peru. This investigation highlights the importance of accurate species diagnosis given the potential for P. falciparum to be reintroduced to regions where it may have been absent. Similar molecular epidemiological investigations can track the probable source(s) of outbreak parasite strains for malaria surveillance and control purposes.

Child Health in the Peruvian Amazon: Prevalence and Factors Associated with Referred Morbidity and Health Care Access in the City of Iñapari.

Introduction. Children under 5 years of age are more susceptible to developing morbidities such as diarrhea, respiratory infections, anemia, and malnutrition. The objective of the study is to evaluate the prevalence of reported morbidities in this age group in the city of Iñapari (Peru) and the access to health services in this municipality. Methods. Data collection using interviews that assessed socioeconomic and demographic conditions, child morbidity, and access to health services was performed in 2011. Statistical analysis was performed using SPSS 13.0. Results. Regarding morbidities that occurred during lifetime, 39.8% reported previous anemia and intestinal parasite infection. About 53.7% of the children reported any type of morbidities in the last 15 days before interview, being most frequent respiratory symptoms (38.9%), diarrhea (23,4%), and fever (23,1%). Only 63.1% of those reporting recent morbidities sought health care. These morbidities were associated with precarious sanitation and lack of infrastructure, the presence of other comorbidities, and poor access to health services. Conclusion. The main referred morbidities in Amazonian Peruvian children were diarrhea, respiratory symptoms, anemia, and vomiting. Incentives and improvements in the health and sanitation conditions would be important measures to improve the quality of life of the Amazonian child population.

Socioeconomic inequities and hepatitis A virus infection in Western Brazilian Amazonian children: spatial distribution and associated factors.

BACKGROUND: Hepatitis A is still a neglected health problem in the world. The most affected areas are the ones with disadvantaged socioeconomic conditions. In Brazil, seroprevalence studies showed that 64.7 % of the general population has antibodies against HAV (hepatitis A virus), and the Amazon region has the highest seroprevalence in the country. METHODS: In the present study the seroprevalence of total HAV antibodies in children between 1 and 5 years old residing in the urban area of Assis Brasil, Acre was measured and spatial distribution of several socioeconomic inequities was evaluated. RESULTS: In the year of 2011, seroprevalence rate was 16.66 %. Factors associated with having a positive serology identified by multivariate analysis were being of indigenous ethnicity [adjusted Odds Ratio (aOR) = 3.27, CI 1.45-7.28], usage of water from the public system (aOR = 8.18, CI 1.07-62.53), living in a house not located in a street (aOR = 3.48, CI 1.54-7.87), and child age over 4 years old (aOR = 2.43, CI 1.23-4.79). The distribution of seropositive children was clustered in the eastern part of the city, where several socioeconomic inequities (lack of flushed toilets, lack of piped water inside the household and susceptibility of the household to flooding during rain, low maternal education, having wood or ground floor at home, and not owning a house, lack of piped water at home, and type of drinking water) also clustered. CONCLUSIONS: The findings highlight that sanitation and water treatment still need improvement in the Brazilian Amazon, and that socioeconomic development is warranted in order to decrease this and other infectious diseases.

[Mansonelosis by mansonella ozzardi in volunteers undergoing screening for malaria in the Peruvian Amazon]. / Mansonelosis por mansonella ozzardi en voluntarios para despistaje de malaria en la amazonía peruana.

OBJECTIVES: To determine the frequency, clinical features, and factors associated with M. ozzardi infection in volunteers of a malaria screening campaign in the district of Alto Nanay in the Amazon jungle of Peru. MATERIALS AND METHODS: A descriptive, analytical and cross-sectional study was performed. The participants were interviewed and examined by a physician and the data were recorded in a medical record. The diagnosis of M. ozzardi infection was performed using the method of thick blood smear and film. RESULTS: The frequency of mansonelosis in this population was 47.8% (95% CI: 39.1 to 56.6). Through bivariate analysis we found that the report of decreased visual acuity or blurred vision and presence of subcutaneous tumors were the signs and symptoms statistically associated with the infection of microfilariae (p<0.05). Logistic regression found statistical association for residency in localities of the Pintuyacu or Alto Nanay rivers, employment in places far from the town center, the presence of subcutaneous tumors and skin thickening (p<0.05). CONCLUSIONS: There was a high number of mansonelosis by M. ozzardi in the district of Alto Nanay which was significantly related to working outside the town center, residing in the area of the Pintuyacu River, and skin lesions.

Prevalencia y factores asociados con la filariosis por Mansonella ozzardi en 2 comunidades periurbanas de Iquitos, 2009 / Prevalence of filariasis by Mansonella ozzardi and associated factors among 2 suburban communities of Iquitos, 2009

Introducción: Tres casos de infección por Mansonella ozzardi (M. ozzardi) en muestras de malaria que provenían de 2 comunidades periurbanas de Iquitos (Perú) dieron la sospecha de transmisión local. El objetivo del estudio fue determinar la prevalencia y factores asociados con la filariosis por M. ozzardi en estas comunidades. Materiales y métodos: Se realizó un estudio transversal en las comunidades de Laguna Azul y La Unión en Iquitos. A todos los pobladores se les tomó una gota gruesa para la detección de M. ozzardi y se les realizó una encuesta epidemiológica. Se realizó colecta de larvas y mosquitos para identificación de potenciales vectores. Se calcularon los OR ajustados (ORa) usando regresión logística múltiple. Resultados: Se evaluaron a 433 personas; 58% fueron mujeres; la mediana de edad fue de 20 años; 58,2% fueron migrantes, 3,7% pescadores y 12,9% habían viajado por las cuencas del Alto anay. La prevalencia de M. ozzardi fue de 1,4% (6/433) y el más joven de los casos tuvo 31 años; se encontró asociación con ser pescador (ORa: 8,7; IC 95: 1,1-76,0) y con haber realizado viajes por la cuenca del Alto Nanay (ORa: 11,2; IC 95: 1,2-112,5). No se evidenció densidad significativa de vectores simúlidos o culicoides. Conclusión: Las comunidades estudiadas tuvieron una baja prevalencia de M. ozzardi y por la edad de los casos y los factores asociados encontrados se sospecha infección foránea a la zona de estudio, en especial en la cuenca del Alto Nanay.

Introduction: Three cases of M. ozzardi infection from 2 suburban communities in Iquitos, Peru, led to a suspicion of local transmission. The objective of the study was to determine the prevalence of filariasis by M. ozzardi and its associated factors among these communities. Materials and methods: A cross-sectional study was performed, as well as an epidemiological survey and a thick smear blood test. Larvae and mosquitoes were collected. The adjusted OR (aOR) using multiple logistic regression was calculated. Results: A total of 433 participants were enrolled; 58% were women. The prevalence of M. ozzardi was 1.4% and the associated factors included being a fisherman (aOR: 8.7; 95%CI: 1.1-76.0) and being on the Alto Nanay river (aOR: 11.2; 95%CI: 1.2-112.5). No significant evidence of simulidos or culicoides was found. Conclusion: The low prevalence of M. ozzardi found suggests a foreign infection, probably derived from the Alto Nanay river.

Mansonelosis por Mansonella ozzardi en voluntarios para despistaje de malaria en la Amazon¡a peruana / Mansonelosis by Mansonella ozzardi in volunteers undergoing screening for malaria in the peruvian Amazon

Objetivos. Determinar la frecuencia, manifestaciones cl¡nicas y factores asociados a la infecci¢n por Mansonella ozzardi en voluntarios de una campa¤a de despistaje de malaria en el distrito de Alto Nanay en la selva amaz¢nica del Per£. Materiales y m‚todos. Se realiz¢ un estudio descriptivo, anal¡tico y transversal. Los participantes fueron entrevistados y examinados por un m‚dico y los datos fueron registrados en una ficha cl¡nica. El diagn¢stico de infecci¢n por M. ozzardi se realiz¢ mediante la t‚cnica de gota gruesa y frotis. Resultados. La frecuencia de mansonelosis en esta poblaci¢n fue 47,8% (IC 95%: 39,1–56,6). Mediante el an lisis bivariado se encontr¢ que el reporte de disminuci¢n de la agudeza visual o visi¢n borrosa y la presencia de tumoraciones subcut neas fueron los signos y s¡ntomas estad¡sticamente asociados con la infecci¢n por microfilarias (p<0,05). La regresi¢n log¡stica encontr¢ asociaci¢n estad¡stica para la residencia en localidades del r¡o Pintuyacu o Alto Nanay, la ocupaci¢n en lugares alejados del centro poblado, la presencia de tumores subcut neos y el engrosamiento de la piel (p<0,05).Conclusiones . Existe una elevada frecuencia de mansonelosis por M. ozzardi en el distrito de Alto Nanay, la cual se encontr¢ significativamente relacionada con ocupaciones realizadas fuera del centro poblado, residencia en localidades del r¡o Pintuyacu y lesiones cut neas.

Objectives. To determine the frequency, clinical features, and factors associated with M. ozzardi infection in volunteers of a malaria screening campaign in the district of Alto Nanay in the Amazon jungle of Peru. Materials and methods. A descriptive, analytical and cross-sectional study was performed. The participants were interviewed and examined by a physician and the data were recorded in a medical record. The diagnosis of M. ozzardi infection was performed using the method of thick blood smear and film. Results.The frequency of mansonelosis in this population was 47.8% (95% CI: 39.1 to 56.6). Through bivariate analysis we found that the report of decreased visual acuity or blurred vision and presence of subcutaneous tumors were the signs and symptoms statistically associated with the infection of microfilariae (p<0.05). Logistic regression found statistical association for residency in localities of the Pintuyacu or Alto Nanay rivers, employment in places far from the town center, the presence of subcutaneous tumors and skin thickening (p<0.05). Conclusions. There was a high number of mansonelosis by M. ozzardi in the district of Alto Nanay which was significantly related to working outside the town center, residing in the area of the Pintuyacu River, and skin lesions.

Molecular Epidemiology of Plasmodium falciparum Malaria Outbreak, Tumbes, Peru, 2010-2012.

During 2010-2012, an outbreak of 210 cases of malaria occurred in Tumbes, in the northern coast of Peru, where no Plasmodium falciparum malaria case had been reported since 2006. To identify the source of the parasite causing this outbreak, we conducted a molecular epidemiology investigation. Microsatellite typing showed an identical genotype in all 54 available isolates. This genotype was also identical to that of parasites isolated in 2010 in the Loreto region of the Peruvian Amazon and closely related to clonet B, a parasite lineage previously reported in the Amazon during 1998-2000. These findings are consistent with travel history of index case-patients. DNA sequencing revealed mutations in the Pfdhfr, Pfdhps, Pfcrt, and Pfmdr1 loci, which are strongly associated with resistance to chloroquine and sulfadoxine/pyrimethamine, and deletion of the Pfhrp2 gene. These results highlight the need for timely molecular epidemiology investigations to trace the parasite source during malaria reintroduction events.

[Mutant alleles associated to chloroquine and sulfadoxine-pyrimethanime resistance in Plasmodium falciparum of the Ecuador-Peru and Ecuador-Colombia borders]. / Alelos mutantes asociados a la resistencia a cloroquina y sulfadoxina-pirimetamina en Plasmodium falciparum de las fronteras Ecuador-Perú y Ecuador-Colombia.

The frequency of mutations in pfCRT and DHFR/DHPS genes of Plasmodium falciparum associated with resistance to chloroquine and sulfadoxine-pyrimethamine was evaluated in 83 strains from the districts of Esmeralda and Machala, located on the borders of Ecuador-Peru and Ecuador-Colombia in 2002. Polymerase chain reaction (PCR), conventional and its variants, was used. Mutations in the pfCRT gene were found in more than 90% of the samples from Esmeralda and Machala. For the DHFR gene, 90% of the strains were mutant samples from Esmeralda, 3 were double mutations and 1 was a triple mutation. In Machala, 25% were simple mutant forms and 75% mixed mutant forms (wild forms/mutant). In conclusion, resistance to chloroquine has been fixed in strains carrying K76T pfCRT mutation, whereas genetic imprinting for resistance to pyrimethamine is evolving, particularly in the district of Esmeralda.

Alelos mutantes asociados a la resistencia a cloroquina y sulfadoxina-pirimetamina en Plasmodium falciparum de las fronteras Ecuador-Perú y Ecuador-Colombia / Mutant alleles associated to chloroquine and sulfadoxine-pyrimethanime resistance in Plasmodium falciparum of the Ecuador-Peru and Ecuador-Colombia borders

Se evaluó la frecuencia de mutaciones en los genes pfCRT y DHFR/DHPS del Plasmodium falciparum asociados a la resistencia a cloroquina y sulfadoxina-pirimetamina en 83 cepas provenientes de los distritos Esmeralda y Machala ubicados en las fronteras entre Ecuador-Perú y Ecuador-Colombia durante el año 2002. Se empleó la reacción en cadena de polimerasa (PCR) convencional y sus variantes. El gen pfCRT presentó más de 90% de muestras mutantes en Esmeralda y Machala. Para el gen DHFR, el 90% de las cepas fueron muestras mutantes en Esmeralda, tres fueron mutaciones dobles y una triple; en Machala se encontró 25% de formas mutantes simples y 75% de formas mixtas (formas silvestres/mutantes). En conclusión, la resistencia a cloroquina se ha fijado en las cepas portadoras de la mutación K76T pfCRT, mientras que la impronta genética a la resistencia a pirimetamina está en evolución, principalmente en el distrito de Esmeralda.

The frequency of mutations in pfCRT and DHFR/DHPS genes of Plasmodium falciparum associated with resistance to chloroquine and sulfadoxine-pyrimethamine was evaluated in 83 strains from the districts of Esmeralda and Machala, located on the borders of Ecuador-Peru and Ecuador-Colombia in 2002. Polymerase chain reaction (PCR), conventional and its variants, was used. Mutations in the pfCRT gene were found in more than 90% of the samples from Esmeralda and Machala. For the DHFR gene, 90% of the strains were mutant samples from Esmeralda, 3 were double mutations and 1 was a triple mutation. In Machala, 25% were simple mutant forms and 75% mixed mutant forms (wild forms/mutant). In conclusion, resistance to chloroquine has been fixed in strains carrying K76T pfCRT mutation, whereas genetic imprinting for resistance to pyrimethamine is evolving, particularly in the district of Esmeralda.

Efficacy of three different regimens of primaquine for the prevention of relapses of Plasmodium vivax malaria in the Amazon Basin of Peru.

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.

Multiple genetic origins of histidine-rich protein 2 gene deletion in Plasmodium falciparum parasites from Peru.

The majority of malaria rapid diagnostic tests (RDTs) detect Plasmodium falciparum histidine-rich protein 2 (PfHRP2), encoded by the pfhrp2 gene. Recently, P. falciparum isolates from Peru were found to lack pfhrp2 leading to false-negative RDT results. We hypothesized that pfhrp2-deleted parasites in Peru derived from a single genetic event. We evaluated the parasite population structure and pfhrp2 haplotype of samples collected between 1998 and 2005 using seven neutral and seven chromosome 8 microsatellite markers, respectively. Five distinct pfhrp2 haplotypes, corresponding to five neutral microsatellite-based clonal lineages, were detected in 1998-2001; pfhrp2 deletions occurred within four haplotypes. In 2003-2005, outcrossing among the parasite lineages resulted in eight population clusters that inherited the five pfhrp2 haplotypes seen previously and a new haplotype; pfhrp2 deletions occurred within four of these haplotypes. These findings indicate that the genetic origin of pfhrp2 deletion in Peru was not a single event, but likely occurred multiple times.

Genetic characterization of atypical Mansonella (Mansonella) ozzardi microfilariae in human blood samples from northeastern Peru.

DNA sequence comparisons are useful for characterizing proposed new parasite species or strains. Microfilariae with an atypical arrangement of nuclei behind the cephalic space have been recently described in human blood samples from the Amazon region of Peru. Three blood specimens containing atypical microfilariae were genetically characterized using three DNA markers (5S ribosomal DNA, 12S ribosomal DNA, and cytochrome oxidase I). All atypical microfilariae were clustered into the Mansonella group and indistinguishable from M. ozzardi based on these DNA markers.