Molecular surveillance of the Plasmodium vivax multidrug resistance 1 gene in Peru between 2006 and 2015.

BACKGROUND: The high incidence of Plasmodium vivax infections associated with clinical severity and the emergence of chloroquine (CQ) resistance has posed a challenge to control efforts aimed at eliminating this disease. Despite conflicting evidence regarding the role of mutations of P. vivax multidrug resistance 1 gene (pvmdr1) in drug resistance, this gene can be a tool for molecular surveillance due to its variability and spatial patterns. METHODS: Blood samples were collected from studies conducted between 2006 and 2015 in the Northern and Southern Amazon Basin and the North Coast of Peru. Thick and thin blood smears were prepared for malaria diagnosis by microscopy and PCR was performed for detection of P. vivax monoinfections. The pvmdr1 gene was subsequently sequenced and the genetic data was used for haplotype and diversity analysis. RESULTS: A total of 550 positive P. vivax samples were sequenced; 445 from the Northern Amazon Basin, 48 from the Southern Amazon Basin and 57 from the North Coast. Eight non-synonymous mutations and three synonymous mutations were analysed in 4,395 bp of pvmdr1. Amino acid changes at positions 976F and 1076L were detected in the Northern Amazon Basin (12.8%) and the Southern Amazon Basin (4.2%) with fluctuations in the prevalence of both mutations in the Northern Amazon Basin during the course of the study that seemed to correspond with a malaria control programme implemented in the region. A total of 13 pvmdr1 haplotypes with non-synonymous mutations were estimated in Peru and an overall nucleotide diversity of π = 0.00054. The Northern Amazon Basin was the most diverse region (π = 0.00055) followed by the Southern Amazon and the North Coast (π = 0.00035 and π = 0.00014, respectively). CONCLUSION: This study showed a high variability in the frequencies of the 976F and 1076L polymorphisms in the Northern Amazon Basin between 2006 and 2015. The low and heterogeneous diversity of pvmdr1 found in this study underscores the need for additional research that can elucidate the role of this gene on P. vivax drug resistance as well as in vitro and clinical data that can clarify the extend of CQ resistance in Peru.

Plasmodium vivax malaria at households: spatial clustering and risk factors in a low endemicity urban area of the northwestern Peruvian coast.

BACKGROUND: Peru has presented a decreasing malaria trend during the last decade, particularly in areas on northwestern coast; however, a limited number of cases continues to be reported yearly mainly in malaria hotspots. METHODS: A two-phase study was conducted to identify spatial and temporal clusters of incident Plasmodium vivax malaria, as well as to determine risk factors associated with households (HH) presenting P. vivax malaria episodes in an urban area of the northwestern Peruvian Coast from June 2008 to May 2010. In the first stage, a full census of the study population was conducted, including geo-referencing of reported P. vivax episodes. In the second stage, a population-based case-control study allowed the identification of risk factors associated with HHs reporting episodes. A total of 117 case HHs with reported P. vivax and 117 control HHs without malaria episodes were assessed. A semi-structured questionnaire was used to interview the head of households and to collect data on HH location and structure, availability of public services, preventive malaria measures, family member with outdoor occupation (farmer, moto-taxi driver), and other HH characteristics. Univariate and multivariate logistic regression analyses were performed to determine case-HH risk factors. SaTScan was used to detect spatial and temporal P. vivax malaria clusters. RESULTS: The most likely spatial cluster of malaria incidence included 1,040 people (22.4% of total population) in 245 HHs (24.6% of total HHs) accounting for 283 malaria episodes (40.1% of total episodes) during the study period (RR = 2.3, p < 0.001). A temporal cluster was also identified from April 12, 2009 to July 4, 2009 accounting for 355 malaria episodes (50.4% of total episodes) (RR = 7.2, p = 0.001). Factors significantly associated with case HHs compared with control HHs were: proximity to water drain < 200 metres (OR = 2.3, 95% CI: 1.3, 4.0); HH size >5 individuals (OR = 1.8, 95% CI: 1.0, 3.2); lack of potable water (OR = 1.8, 95% CI: 1.1, 3.2); and having domestic and peridomestic animals (OR = 3.6, 95% CI: 1.3, 9.5). CONCLUSION: Plasmodium vivax malaria incidence is highly heterogeneous in space and time in the urban study area with important geographical and housing risk factors associated with symptomatic episodes.

Assessing malaria transmission in a low endemicity area of north-western Peru.

BACKGROUND: Where malaria endemicity is low, control programmes need increasingly sensitive tools for monitoring malaria transmission intensity (MTI) and to better define health priorities. A cross-sectional survey was conducted in a low endemicity area of the Peruvian north-western coast to assess the MTI using both molecular and serological tools. METHODS: Epidemiological, parasitological and serological data were collected from 2,667 individuals in three settlements of Bellavista district, in May 2010. Parasite infection was detected using microscopy and polymerase chain reaction (PCR). Antibodies to Plasmodium vivax merozoite surface protein-119 (PvMSP119) and to Plasmodium falciparum glutamate-rich protein (PfGLURP) were detected by ELISA. Risk factors for exposure to malaria (seropositivity) were assessed by multivariate survey logistic regression models. Age-specific antibody prevalence of both P. falciparum and P. vivax were analysed using a previously published catalytic conversion model based on maximum likelihood for generating seroconversion rates (SCR). RESULTS: The overall parasite prevalence by microscopy and PCR were extremely low: 0.3 and 0.9%, respectively for P. vivax, and 0 and 0.04%, respectively for P. falciparum, while seroprevalence was much higher, 13.6% for P. vivax and 9.8% for P. falciparum. Settlement, age and occupation as moto-taxi driver during previous year were significantly associated with P. falciparum exposure, while age and distance to the water drain were associated with P. vivax exposure. Likelihood ratio tests supported age seroprevalence curves with two SCR for both P. vivax and P. falciparum indicating significant changes in the MTI over time. The SCR for PfGLURP was 19-fold lower after 2002 as compared to before (λ1 = 0.022 versus λ2 = 0.431), and the SCR for PvMSP119 was four-fold higher after 2006 as compared to before (λ1 = 0.024 versus λ2 = 0.006). CONCLUSION: Combining molecular and serological tools considerably enhanced the capacity of detecting current and past exposure to malaria infections and related risks factors in this very low endemicity area. This allowed for an improved characterization of the current human reservoir of infections, largely hidden and heterogeneous, as well as providing insights into recent changes in species specific MTIs. This approach will be of key importance for evaluating and monitoring future malaria elimination strategies.

Plasmodium vivax hospitalizations in a monoendemic malaria region: severe vivax malaria?

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.

Detection of Rickettsia parkeri from within Piura, Peru, and the first reported presence of Candidatus Rickettsia andeanae in the tick Rhipicephalus sanguineus.

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.

[Risk sexual behavior among people living with HIV/AIDS and receiving antiretroviral therapy in Piura, Peru]. / Percepciones sobre comportamientos sexuales de riesgo en personas que viven con VIH/SIDA y reciben tratamiento antirretroviral en Piura, Perú.

OBJECTIVE: To explore opinions and beliefs about risky sexual behavior and HIH transmission in tow hospital of Piura. MATERIAL AND METHODS: Qualitative study based on extensive interviews and focus groups of people over 15 years old of age living with HIV. Interviews were recorded as audio, and then transcribed as text in MS Word. Information was analyzed with AtlasTi. RESULTS: Results indicate that people living with HIV and receive antiretrovirals practice risky sexual behavior. Those results agree with quantitative-epidemiological studies establishing that TARGA era is associated with continuation or increase of risky sexual behavior. Two reasons could explain such behavior; first there is a belief that HIV is innocuous by effect of the antiretrovirals. Second, there is belief that a medical confirmation of undetectable viral count means being healed from infection. CONCLUSIONS: People living with HIV receiving antiretrovirals improving general health status maintain risky sexual behavior that may facilitate HIV transmission to their serodiscordant partners and increase the number of people infected. Until now, prevention activities mostly targeted people believed not to be infected, however, it is also necessary an intense secondary prevention effort that includes an explicit approach of sexuality in its entire dimension.

[Concurrent infections by two dengue virus serotypes during an outbreak in northwestern Peru, 2008]. / Infecciones concurrentes por dos serotipos del virus dengue durante un brote en el noroeste de Perú, 2008.

OBJECTIVES: To establish the existence of concurrent infections by different dengue virus (DENV) serotypes in an outbreak in the Northwestern in Peru during 2008. MATERIAL AND METHODS: 73 serum samples from patients with dengue were analyzed during an outbreak that occurred in Northwestern in Peru between May and June 2008. Molecular biology techniques were used to serotype the DENV, thus, firstly the viral RNA viral was extracted using Viral QIAamp RNA mini kit (Qiagen, Valencia, California, USA), then the viral cDNA fragments were reverse transcripted and amplified by means of the Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and the RT-Nested PCR region techniques and finally, genetic sequencing of the viral cDNA fragments were performed using the Big Dye Terminator v.3,1 kit. RESULTS: The 73 dengue cases presented infections by different serotypes: 34 (46.6%) by DENV-3, 29 (39.7%) by DENV-1, 4 (5.5%) by DENV-4, and 6 (8.2%) concurrent infections by DENV-1 and DENV-3. The most frequent clinical manifestations observed among dengue patients were fever and headache (100%), myalgia (94.5%), ocular pain (83.6%), arthralgia (78.1%), shivers (63.0%), nausea/vomiting (38.4%), positive tourniquet test (30.1%), and rash (20.5%). All patients with concurrent infections presented light clinical course of dengue fever (DF) except one patient who had moderate hemorrhagic manifestations. CONCLUSION: This is the first Peruvian report of patients with concurrent infections of two DENV serotypes without severe clinical manifestations.

Influenza-like illness sentinel surveillance in Peru.

BACKGROUND: Acute respiratory illnesses and influenza-like illnesses (ILI) are a significant source of morbidity and mortality worldwide. Despite the public health importance, little is known about the etiology of these acute respiratory illnesses in many regions of South America. In 2006, the Peruvian Ministry of Health (MoH) and the US Naval Medical Research Center Detachment (NMRCD) initiated a collaboration to characterize the viral agents associated with ILI and to describe the clinical and epidemiological presentation of the affected population. METHODOLOGY/PRINCIPAL FINDINGS: Patients with ILI (fever > or =38 degrees C and cough or sore throat) were evaluated in clinics and hospitals in 13 Peruvian cities representative of the four main regions of the country. Nasal and oropharyngeal swabs, as well as epidemiological and demographic data, were collected from each patient. During the two years of this study (June 2006 through May 2008), a total of 6,835 patients, with a median age of 13 years, were recruited from 31 clinics and hospitals; 6,308 were enrolled by regular passive surveillance and 527 were enrolled as part of outbreak investigations. At least one respiratory virus was isolated from the specimens of 2,688 (42.6%) patients, with etiologies varying by age and geographical region. Overall the most common viral agents isolated were influenza A virus (25.1%), influenza B virus (9.7%), parainfluenza viruses 1, 2, and 3, (HPIV-1,-2,-3; 3.2%), herpes simplex virus (HSV; 2.6%), and adenoviruses (1.8%). Genetic analyses of influenza virus isolates demonstrated that three lineages of influenza A H1N1, one lineage of influenza A H3N2, and two lineages of influenza B were circulating in Peru during the course of this study. CONCLUSIONS: To our knowledge this is the most comprehensive study to date of the etiologic agents associated with ILI in Peru. These results demonstrate that a wide range of respiratory pathogens are circulating in Peru and this fact needs to be considered by clinicians when treating patients reporting with ILI. Furthermore, these data have implications for influenza vaccine design and implementation in South America.

Percepciones sobre comportamientos sexuales de riesgo en personas que viven con VIH/Sida y reciben tratamiento antirretroviral en Piura, Perú / Risk sexual behavior among people living with HIV/AIDS and receiving antiretroviral therapy in Piura, Peru

Objetivo. Explorar y describir experiencias y motivaciones de las personas que viven con VIH (PVVS) y reciben tratamiento antirretroviral de gran actividad (TARGA), para tener comportamientos sexuales de riesgo para transmisión del VIH, en dos hospitales públicos de Piura. Materiales y métodos. Estudio cualitativo basado en entrevistas en profundidad y grupos focales en 40 PVVS, de 15 a 39 años de edad, cuyo análisis se realizó bajo el enfoque de la teoría fundamentada, se realizó un análisis por categorías, se usó el software ATLAS.Ti Versión 5.0. Resultados. Las PVVS que reciben TARGA tienen comportamientos sexuales de riesgo. Esto concuerda con estudios cuantitativos-epidemiológicos que afirman que el inicio de la era TARGA está relacionada con continuación o incremento de comportamientos sexuales de riesgo. Conclusiones. Las PVVS al recibir antirretrovirales y mejorar el estado de su salud, mantienen comportamientos sexuales de riesgo que podrían facilitar la transmisión del virus a sus parejas serodiscordantes e incrementar el número de casos con esta infección. Hasta el momento, las actividades de prevención se han dirigido mayormente hacia personas que se supone no están infectadas, no obstante, se requiere también de un trabajo intenso de prevención secundaria, que incluya explícitamente el abordaje de la sexualidad en todas sus dimensiones.

Objetive. To explore opinions and beliefs about risky sexual behavior and HIH transmission in tow hospital of Piura. Material y methods. Qualitative study based on extensive interviews and focus groups of people over 15 years oldof age living with HIV. Interviews were recorded as audio, and then transcribed as text in MS Word. Information was analyzed with AtlasTi. Results. Results indicate that people living with HIV and receive antiretrovirals practice riskysexual behavior. Those results agree with quantitative-epidemiological studies establishing that TARGA era is associated with continuation or increase of risky sexual behavior. Two reasons could explain such behavior; first there is a belief that HIV is innocuous by effect of the antiretrovirals. Second, there is belief that a medical confirmation of undetectable viral count means being healed from infection. Conclusions. People living with HIV receiving antiretrovirals improving general health status maintain risky sexual behavior that may facilitate HIV transmission to their serodiscordant partnersand increase the number of people infected. Until now, prevention activities mostly targeted people believed not to be infected, however, it is also necessary an intense secondary prevention effort that includes an explicit approach of sexuality in its entire dimension.

Infecciones concurrentes por dos serotipos del virus dengue durante un brote en el noroeste de Perú, 2008 / Concurrent infections by two dengue virus serotypes during an outbreak in northwestern Peru, 2008

Objetivo. Describir la existencia de infecciones concurrentes por diferentes serotipos del virus dengue (DENV) enun brote ocurrido en el noroeste de Perú durante el 2008. Materiales y métodos. Se analizó 73 muestras séricas de pacientes con dengue en un brote en el noroeste de Perú entre mayo y junio de 2008. Para la serotipificación del DENV se utilizó técnicas de biología molecular; así, primero se realizó la extracción del ARN con el kit QIAamp viral RNA Mini, luego se realizó la transcripción inversa y amplificación de los fragmentos de ADNc viral mediante las técnicas de reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR multiplex) y de RT-Anidada PCR(RT-Nested PCR), y finalmente de realizó el secuenciamiento genético de los fragmentos de ADNc viral utilizando el kit Big Dye Terminator v.3,1. Resultados. Los 73 casos de dengue presentaron infecciones por diferentes serotipos: 34 (46,6%) por DENV-3, 29 (39,7 por ciento) por DENV-1, 4 (5,5 por ciento) por DENV-4 y 6 casos (8,2 por ciento) por DENV-1 y DENV-3. Las manifestaciones clínicas más frecuentes fueron fiebre y cefalea (100 por ciento), mialgia (94,5 por ciento), dolor ocular (83,6 por ciento ), artralgia (78,1 por ciento), escalofríos (63,0 por ciento), nauseas/vómitos (38,4 por ciento), prueba de lazo positiva (30,1 por ciento) y erupción cutánea (20,5 por ciento). Los pacientes con infecciones concurrentes presentaron cuadros leves, excepto una paciente que presentó prueba de lazo positivo y sangrado genital. Conclusión. Es el primer reporte de pacientes peruanos con infecciones concurrentes por dos serotipos del DENV sin formas graves de la enfermedad.

Objetives. To establish the existence of concurrent infections by different dengue virus (DENV) serotypes in an outbreak in the Northwestern in Peru during 2008. Material and methods. 73 serum samples from patients with dengue were analyzed during an outbreak that occurred in Northwestern in Peru between May and June 2008. Molecular biology techniques were used to serotype the DENV, thus, firstly the viral RNA viral was extracted using Viral QIAamp RNA mini kit (Qiagen, Valencia, California, USA), then the viral cDNA fragments were reverse transcripted and amplified by means of the Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and the RT-Nested PCR region techniques and finally, genetic sequencing of the viral cDNA fragments were performed using the Big Dye Terminator v.3,1 kit. Results. The 73 dengue cases presented infections by different serotypes: 34 (46.6 per cent) by DENV-3, 29 (39.7 per cent) by DENV-1, 4 (5.5 per cent) by DENV-4, and 6 (8.2 per cent) concurrent infections by DENV-1 and DENV-3. The most frequent clinical manifestations observed among dengue patients were fever and headache (100 per cent), myalgia (94.5 per cent), ocular pain (83.6 per cent), arthralgia (78.1 per cent), shivers(63.0 per cent), nausea/vomiting (38.4 per cent), positive tourniquet test (30.1 per cent), and rash (20.5 per cent). All patients with concurrent infections presented light clinical course of dengue fever (DF) except one patient who had moderate hemorrhagic manifestations. Conclusion. This is the first Peruvian report of patients with concurrent infections of two DENV serotypes without severe clinical manifestations.

Factores asociados a la infestación intradomiciliaria por Aedes aegypti en el distrito de Tambogrande, Piura 2004 / Associated factors to the intradomiciliary infestation of Aedes aegypti at Tambogrande district, Piura 2004

Objetivos: Determinar los factores asociados para la infestación de las viviendas por Aedes aegypti en el distrito de Tambogrande, Piura. Materiales y métodos: Realizamos un estudio de casos y controles en la capital del distrito de Tambogrande, en diciembre de 2004. Consideramos como vivienda-caso (Vc) a la vivienda positiva a la infestación por Ae. aegypti, y vivienda-control (Vo) a la vivienda negativa a la infestación por Ae. aegypti en por lo menos un año, de acuerdo a los registros de las actividades de control larvario. Por cada caso consideramos dos controles. La encuesta incluyó factores ambientales, sociales y culturales, y se aplicó a la persona encargada del cuidado de la vivienda. Los factores asociados con un valor de p menor que 0,10 en el análisis bivariado, fueron ingresados a un modelo de regresión logística para estimar los OR ajustados y los intervalos de confianza al 95 por ciento (IC). Resultados: Encuestamos 60 Vc y 124 Vo. Los factores asociados encontrados en modelo logístico múltiple fueron la presencia de botellas dentro de la vivienda (OR: 7,66; IC: 2,95-19,84), vivienda ubicada a menos de 200 m de una llantería (OR: 2,90; IC: 1,13-7,48), vivienda ubicada a menos de 200 m. de una maderera (OR: 2,76; IC: 1,14-6,66) y tener un jardín en el interior de la vivienda (OR: 2.31; IC: 0,98-7,48). Tener una trabajadora del hogar en la vivienda fue un factor protector (OR: 0,07; IC: 0,014- 0,37).Conclusiones: Los factores identificados deben ser tomados en cuenta para el desarrollo de programas de controlvectorial en Tambogrande.

Objectives: To determine the associated factors to the intradomiciliary infestation for Ae. aegypti in Tambogrande district, Piura (Northern Coastal of Peru). Material and methods: We conducted a case control study in the capital of district of Tambogrande, in December of the 2004. We regarded as housing-case (Hc) to the positive housing for Ae. aegypti infestation, and control housing (Ho) to the negative housing for Ae. aegypti infestation in at least a year with the following criteria, housing once was located in the districtÆs capital, according to the larval control register activities. For each case we considered two controls. We apply to the person in charge of the housingÆs care that we included environmental, social and cultural factors in the questionnaire. Associates factors with p minor than 0,10 value in the univariateanalysis they were included in logistic regression model to estimate them OR adjusted and 95 porcentage confidence intervals (CI). Results: We poll 60 Vc and 124 Vo. The associated factors found in the multiple logistic model they went the presence of bottles in housing (OR: 7,66; CI: 2,95 - 19,84), household located at less than 200 m from a tire deposit (OR: 2,90; CI:1,13 - 7,48), household located at less than 200 m from a wood deposit (OR: 2,76; CI:1,14 - 6,66), and householdswith an inner garden (OR: 2.31; CI: 0,98 - 7,48) were statistically significant. We also identified that a household that has a maid (OR: 0,07; CI: 0,14 - 0,37) was a protective factor. Conclusions: The factors identified should be taken intoaccount in the development of vector control programs in Tambogrande.