Medico, Tropicalista, dedicado a la investigación en Malaria y otras enfermedades Metaxénicas, Actualmente en el Ministerio de Salud del Perú en el equipo del control de la COVID-19
Revista peruana de medicina experimental y salud pública/Revista peruana de medicina experimental y salud pública, May 8, 2024
a Médico cirujano; b biólogo; c licenciado en Ecología; d ingeniero. RESUMEN Objetivo. Estimar lo... more a Médico cirujano; b biólogo; c licenciado en Ecología; d ingeniero. RESUMEN Objetivo. Estimar los costos incurridos en el control del Aedes aegypti en la región Loreto, en los años 2017 y 2018. Materiales y métodos. Se realizó una evaluación económica retrospectiva parcial de los costos del control del Aedes aegypti de la Dirección Regional de Salud Loreto, durante la ejecución del Plan Regional de Vigilancia y Control de Aedes aegypti. Se revisó documentación como planes, informes de intervenciones y planillas de pago y se realizaron entrevistas al personal profesional implicado en el control vectorial, sobre los costos de las intervenciones de control. Resultados. Se halló, que los costos incurridos en el control del vector del dengue en la Región Loreto en los dos años estudiados ascienden a: 3,807,858 PEN y 4,066,380 PEN durante el 2017 y 2018, respectivamente (1´175,264 USD y 1´1210,232 USD al tipo de cambio del 2017 y 2018). Sin embargo, el efecto de las actividades de control es de corta duración. Conclusiones. El alto costo que implica el control vectorial con los métodos usados actualmente y la corta duración de su efecto lo hace insostenible. Se deben realizar estudios para hallar otros métodos más eficientes para el control del dengue.
medRxiv (Cold Spring Harbor Laboratory), Dec 20, 2023
Objectives: Vector control is the method of prevention and control of dengue outbreaks used in Pe... more Objectives: Vector control is the method of prevention and control of dengue outbreaks used in Peru. With the objective of calculating the costs incurred in vector control, an estimation of the costs of Aedes aegypti control of the Regional Health Directorate of Loreto, during the execution of the regional plan for surveillance and control of A. aegypti was carried out. Materials and methods: Documentation was reviewed, and interviews were conducted with stakeholders about the costs of A. aegypti control interventions in its adult and larval stages, during 2017 and 2018. Results: It was found that the costs incurred in the control of the dengue vector in the Loreto Region in the two years studied
Objectives: Vector control is the method of prevention and control of dengue outbreaks used in Pe... more Objectives: Vector control is the method of prevention and control of dengue outbreaks used in Peru. With the objective of calculating the costs incurred in vector control, an estimation of the costs of Aedes aegypti control of the Regional Health Directorate of Loreto, during the execution of the regional plan for surveillance and control of A. aegypti was carried out. Materials and methods: Documentation was reviewed, and interviews were conducted with stakeholders about the costs of A. aegypti control interventions in
American Journal of Tropical Medicine and Hygiene, Apr 1, 2007
High levels of Plasmodium falciparum resistance to both chloroquine (CQ) and sulfadoxinepyrimetha... more High levels of Plasmodium falciparum resistance to both chloroquine (CQ) and sulfadoxinepyrimethamine (SP) have been documented throughout the Amazon Basin of South America. Because of reports about the persistent efficacy of both of these drugs in the northwestern Peruvian Amazon region, we carried out an evaluation of the therapeutic efficacy of chloroquine (25 mg/kg) and SP (25 mg/kg of the sulfadoxine component) for the treatment of uncomplicated P. falciparum infections at two sites: Ullpayacu and Pampa Hermoza/Alianza. A total of 111 patients were enrolled. Only 5 (14.3%) of the 35 patients who received CQ had an adequate clinical and parasitologic response (ACPR). Six subjects (17%) had early treatment failure, 1 (2.9%) had late clinical failure, and 23 (65.7%) had late parasitologic failure (LPF). Of the subjects treated with SP, 92.3% had ACPR and 7.7% had LPF. Based on these findings, it is clear that there are at least limited areas within the Peruvian Amazon region where P. falciparum strains continue to be sensitive to SP.
Vector-borne infections (VBI) are defined as infectious diseases transmitted by the bite or mecha... more Vector-borne infections (VBI) are defined as infectious diseases transmitted by the bite or mechanical transfer of arthropod vectors. They constitute a significant proportion of the global infectious disease burden. United States (U.S.) Department of Defense (DoD) personnel are especially vulnerable to VBIs due to occupational contact with arthropod vectors, immunological naiveté to previously unencountered pathogens, and limited diagnostic and treatment options available in the austere and unstable environments sometimes associated with military operations. In addition to the risk uniquely encountered by military populations, other factors have driven the worldwide emergence of VBIs. Unprecedented levels of global travel, tourism and trade, and blurred lines of demarcation between zoonotic VBI reservoirs and human populations increase vector exposure. Urban growth in previously undeveloped regions and perturbations in global weather patterns also contribute to the rise of VBIs. The Armed Forces Health Surveillance Center-Global Emerging Infections Surveillance and Response System (AFHSC-GEIS) and its partners at DoD overseas laboratories form a network to better characterize the nature, emergence and growth of VBIs globally. In 2009 the network tested 19,730 specimens from 25 sites for Plasmodium species and malaria drug resistance phenotypes and nearly another 10,000 samples to determine the etiologies of non-Plasmodium species VBIs from regions spanning from Oceania to Africa, South America, and northeast, south and Southeast Asia. This review describes recent VBI-related epidemiological studies conducted by AFHSC-GEIS partner laboratories within the OCONUS DoD laboratory network emphasizing their impact on human populations.
Background: A major concern in malaria vaccine development is genetic polymorphisms typically obs... more Background: A major concern in malaria vaccine development is genetic polymorphisms typically observed among Plasmodium isolates in different geographical areas across the world. Highly polymorphic regions have been observed in Plasmodium falciparum and Plasmodium vivax antigenic surface proteins such as Circumsporozoite protein (CSP), Duffy-binding protein (DBP), Merozoite surface protein-1 (MSP-1), Apical membrane antigen-1 (AMA-1) and Thrombospondin related anonymous protein (TRAP). Methods: Genetic variability was assessed in important polymorphic regions of various vaccine candidate antigens in P. vivax among 106 isolates from the Amazon Region of Loreto, Peru. In addition, genetic diversity determined in Peruvian isolates was compared to population studies from various geographical locations worldwide. Results: The structured diversity found in P. vivax populations did not show a geographic pattern and haplotypes from all gene candidates were distributed worldwide. In addition, evidence of balancing selection was found in polymorphic regions of the trap, dbp and ama-1 genes. Conclusions: It is important to have a good representation of the haplotypes circulating worldwide when implementing a vaccine, regardless of the geographic region of deployment since selective pressure plays an important role in structuring antigen diversity.
Transactions of The Royal Society of Tropical Medicine and Hygiene
Background Anaemia is a public health problem in Peru. In the Loreto region of the Amazon, ≥50% o... more Background Anaemia is a public health problem in Peru. In the Loreto region of the Amazon, ≥50% of children may be anaemic, although insufficient information exists for rural villages. Methods To generate more data about childhood anaemia in the Peruvian Amazon, haemoglobin was measured as part of a trachoma survey in 21 randomly selected villages. All children 1–9 y of age from 30 randomly selected households per village were recruited. Anaemia was classified according to the World Health Organization guidelines and a socio-economic status (SES) index was created for each household using principal component analysis. Spatial autocorrelation was determined using Moran's I and Ripley's K function. Results Of 678 children with complete haemoglobin data, 25.4% (95% confidence interval [CI] 21.2 to 30.1) had mild-or-worse anaemia and 22.1% (95% CI 15.6 to 30.3) had moderate-or-worse anaemia. Mild-or-worse anaemia was more common among children whose primary source of drinking wa...
Objective To determine the relationship between socioeconomic status (SES) and visual impairment ... more Objective To determine the relationship between socioeconomic status (SES) and visual impairment (VI) or blindness in the rural Peruvian Amazon, hypothesizing that higher SES would have a protective effect on the odds of VI or blindness. Methods In this cross-sectional study of 16 rural communities in the Peruvian Amazon, consenting adults aged ≥ 50 years were recruited from ~30 randomly selected households per village. Each household was administered a questionnaire and had a SES score constructed using principal components analysis. Blindness and VI were determined using a ministry of health 3-meter visual acuity card. Results Overall, 207 adults aged ≥ 50 were eligible; 146 (70.5%) completed visual acuity screening and answered the questionnaire. Of those 146 participants who completed presenting visual acuity screening, 57 (39.0%, 95% CI 30.2–47.1) were classified as visually impaired and 6 (4.1%, 95% CI 0.9–7.3) as blind. Belonging to the highest SES tercile had a protective ef...
Sr. Editor, Hemos leído atentamente los comentarios al artículo titulado “Frecuencia elevada de d... more Sr. Editor, Hemos leído atentamente los comentarios al artículo titulado “Frecuencia elevada de dengue grave durante la epidemia por el Linaje II del DENV-2 americano/asiático en el Perú” (1), publicados en su prestigiosa revista. Agradecemos el interés por el mismo y hacemos algunas precisiones.
Background A major concern in malaria vaccine development is genetic polymorphisms typically obse... more Background A major concern in malaria vaccine development is genetic polymorphisms typically observed among Plasmodium isolates in different geographical areas across the world. Highly polymorphic regions have been observed in Plasmodium falciparum and Plasmodium vivax antigenic surface proteins such as Circumsporozoite protein (CSP), Duffy-binding protein (DBP), Merozoite surface protein-1 (MSP-1), Apical membrane antigen-1 (AMA-1) and Thrombospondin related anonymous protein (TRAP). Methods Genetic variability was assessed in important polymorphic regions of various vaccine candidate antigens in P. vivax among 106 isolates from the Amazon Region of Loreto, Peru. In addition, genetic diversity determined in Peruvian isolates was compared to population studies from various geographical locations worldwide. Results The structured diversity found in P. vivax populations did not show a geographic pattern and haplotypes from all gene candidates were distributed worldwide. In addition, e...
Introducción. El ingreso del linaje II del DENV-2 americano/asiático en la región Loreto de la Am... more Introducción. El ingreso del linaje II del DENV-2 americano/asiático en la región Loreto de la Amazonia Peruana, coincidió con un incremento súbito de los casos de dengue con necesidad de hospitalización. Sin embargo, las estadísticas oficiales reportaron pocos casos graves. Se postula, que existió una subnotificación de los casos graves en los reportes oficiales del Ministerio de Salud. Objetivos. Conocer la frecuencia de pacientes con signos de gravedad entre los pacientes hospitalizados por dengue probable durante el brote del 2011 en el Hospital Iquitos, Perú. Métodos. Se realizó un estudio longitudinal, aplicando una lista de chequeo diaria, sobre la presencia de signos de gravedad durante la estancia hospitalaria, a un grupo de pacientes hospitalizados en la unidad de dengue del Hospital Iquitos. Resultados. De 178 pacientes evaluados 66 (37%, IC: 29,9 – 44,6%) presentaron algún signo de gravedad, la mayor parte por shock (75,7%). Este resultado contrasta con el número de paci...
Background: Malaria in Peru is concentrated in the Amazon region, especially in Loreto, and trans... more Background: Malaria in Peru is concentrated in the Amazon region, especially in Loreto, and transmission is focused in rural and peri-urban communities. The government has approved a malaria elimination plan with a community approach and seeks to reduce the risk of transmission through preventive interventions, but asymptomatic and low-parasite-density infections are challenges for disease control and elimination. IgG antibodies play a critical role in combating infection through their ability to reduce parasitaemia and clinical symptoms. In particular, IgG subclasses have important roles in controlling malaria disease and may provide new insight into the development of malaria control strategies and understanding of malaria transmission. Through the use of excreted-secreted antigens from Plasmodium falciparum, were evaluated the responses of the four IgG subclasses in symptomatic and asymptomatic malarial infections. Results: Higher levels of whole IgG were observed in asymptomatic carriers (P < 0.05). IgG3 and IgG1 were the most prevalent subclasses and did not show differences in their antibody levels in either type of carrier. All symptomatic carriers were positive for IgG4, and the presence of IgG3 and IgG2 were correlated with protection against parasitaemia. IgG2 showed lower prevalence and antibody titers in comparison to other subclasses. Conclusions: This is the first study that characterizes the IgG subclass response in the Peruvian Amazon, and these results show that even in populations from regions with low malaria transmission, a certain degree of naturally acquired immunity can develop when the right antibody subclasses are produced. This provides important insight into the potential mechanisms regulating protective immunity.
Revista Peruana de Medicina Experimental y Salud Pública, 2011
We conducted a clinical description of confirmed dengue cases admitted to the Hospital " César Ga... more We conducted a clinical description of confirmed dengue cases admitted to the Hospital " César Garayar García" in Iquitos from January 25 to February 5, 2011. According to current WHO classification, major warning signs leading to hospitalization were: abdominal pain (28/28) and persistent vomiting (15/28), the causes of severity were: hypotension (9 / 13), severe bleeding (6 / 13) and plasma extravasation with respiratory distress (4 / 13). The median patient age was 22 years, however, 8 / 13 patients classified as severe dengue were under 16 years. In conclusion, unlike previous epidemics, we found a high involvement of young people and severity in the clinical presentation predominating a high frequency of shock (hypotension) and vascular leakage, which could be related to the circulation of an emerging variant DENV-2 which is more virulent.
Severe malaria caused by Plasmodium vivax is no longer considered rare. To describe its clinical ... more 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.
Revista Peruana de Medicina Experimental y Salud Pública, 2004
Objetivos: Como respuesta a la emergencia de la resistencia del P. falciparum a los antimaláricos... more Objetivos: Como respuesta a la emergencia de la resistencia del P. falciparum a los antimaláricos, el Ministerio de Salud del Perú decidió adoptar los esquemas de tratamiento para malaria combinados recomendados por la OMS: MQ-AS y SP-AS, pero el costo de la nueva terapia es significativamente superior a los anteriores esquemas; SP y quinina + tetraciclina, sin embargo tendría como ventaja una mayor eficacia y probablemente la capacidad de disminuir la transmisión. Por estos motivos se evaluó de manera prospectiva el costo efectividad del cambio en los esquemas de tratamiento para malaria. Materiales y métodos: Se uso el método de análisis de decisiones y de riesgos, se construyó un modelo probabilística que estableció las relaciones formales entre diversos factores que van a modificar el número de casos, muertes, los años de vida ajustados por discapacidad (AVAD) y los costos del programa en un periodo de cinco años. Resultados: Se halló que si bien el costo unitario por tratamient...
Outdoor malaria transmission hinders malaria elimination efforts in the Amazon region and novel v... more Outdoor malaria transmission hinders malaria elimination efforts in the Amazon region and novel vector control tools are needed. Ivermectin mass drug administration (MDA) to humans kills wild Anopheles, targets outdoor-feeding vectors, and can suppress malaria parasite transmission. Laboratory investigations were performed to determine ivermectin susceptibility, sporontocidal effect and inhibition of time to re-feed for the primary Amazonian malaria vector, Anopheles darlingi. To assess ivermectin susceptibility, various concentrations of ivermectin were mixed in human blood and fed to An. darlingi. Mosquito survival was monitored daily for 7 days and a non-linear mixed effects model with Probit analysis was used to calculate lethal concentrations of ivermectin that killed 50% (LC50), 25% (LC25) and 5% (LC5) of mosquitoes. To examine ivermectin sporonticidal effect, Plasmodium vivax blood samples were collected from malaria patients and offered to mosquitoes without or with ivermect...
Severe malaria caused by Plasmodium vivax is no longer considered rare. To describe its clinical ... more 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.
Revista peruana de medicina experimental y salud pública/Revista peruana de medicina experimental y salud pública, May 8, 2024
a Médico cirujano; b biólogo; c licenciado en Ecología; d ingeniero. RESUMEN Objetivo. Estimar lo... more a Médico cirujano; b biólogo; c licenciado en Ecología; d ingeniero. RESUMEN Objetivo. Estimar los costos incurridos en el control del Aedes aegypti en la región Loreto, en los años 2017 y 2018. Materiales y métodos. Se realizó una evaluación económica retrospectiva parcial de los costos del control del Aedes aegypti de la Dirección Regional de Salud Loreto, durante la ejecución del Plan Regional de Vigilancia y Control de Aedes aegypti. Se revisó documentación como planes, informes de intervenciones y planillas de pago y se realizaron entrevistas al personal profesional implicado en el control vectorial, sobre los costos de las intervenciones de control. Resultados. Se halló, que los costos incurridos en el control del vector del dengue en la Región Loreto en los dos años estudiados ascienden a: 3,807,858 PEN y 4,066,380 PEN durante el 2017 y 2018, respectivamente (1´175,264 USD y 1´1210,232 USD al tipo de cambio del 2017 y 2018). Sin embargo, el efecto de las actividades de control es de corta duración. Conclusiones. El alto costo que implica el control vectorial con los métodos usados actualmente y la corta duración de su efecto lo hace insostenible. Se deben realizar estudios para hallar otros métodos más eficientes para el control del dengue.
medRxiv (Cold Spring Harbor Laboratory), Dec 20, 2023
Objectives: Vector control is the method of prevention and control of dengue outbreaks used in Pe... more Objectives: Vector control is the method of prevention and control of dengue outbreaks used in Peru. With the objective of calculating the costs incurred in vector control, an estimation of the costs of Aedes aegypti control of the Regional Health Directorate of Loreto, during the execution of the regional plan for surveillance and control of A. aegypti was carried out. Materials and methods: Documentation was reviewed, and interviews were conducted with stakeholders about the costs of A. aegypti control interventions in its adult and larval stages, during 2017 and 2018. Results: It was found that the costs incurred in the control of the dengue vector in the Loreto Region in the two years studied
Objectives: Vector control is the method of prevention and control of dengue outbreaks used in Pe... more Objectives: Vector control is the method of prevention and control of dengue outbreaks used in Peru. With the objective of calculating the costs incurred in vector control, an estimation of the costs of Aedes aegypti control of the Regional Health Directorate of Loreto, during the execution of the regional plan for surveillance and control of A. aegypti was carried out. Materials and methods: Documentation was reviewed, and interviews were conducted with stakeholders about the costs of A. aegypti control interventions in
American Journal of Tropical Medicine and Hygiene, Apr 1, 2007
High levels of Plasmodium falciparum resistance to both chloroquine (CQ) and sulfadoxinepyrimetha... more High levels of Plasmodium falciparum resistance to both chloroquine (CQ) and sulfadoxinepyrimethamine (SP) have been documented throughout the Amazon Basin of South America. Because of reports about the persistent efficacy of both of these drugs in the northwestern Peruvian Amazon region, we carried out an evaluation of the therapeutic efficacy of chloroquine (25 mg/kg) and SP (25 mg/kg of the sulfadoxine component) for the treatment of uncomplicated P. falciparum infections at two sites: Ullpayacu and Pampa Hermoza/Alianza. A total of 111 patients were enrolled. Only 5 (14.3%) of the 35 patients who received CQ had an adequate clinical and parasitologic response (ACPR). Six subjects (17%) had early treatment failure, 1 (2.9%) had late clinical failure, and 23 (65.7%) had late parasitologic failure (LPF). Of the subjects treated with SP, 92.3% had ACPR and 7.7% had LPF. Based on these findings, it is clear that there are at least limited areas within the Peruvian Amazon region where P. falciparum strains continue to be sensitive to SP.
Vector-borne infections (VBI) are defined as infectious diseases transmitted by the bite or mecha... more Vector-borne infections (VBI) are defined as infectious diseases transmitted by the bite or mechanical transfer of arthropod vectors. They constitute a significant proportion of the global infectious disease burden. United States (U.S.) Department of Defense (DoD) personnel are especially vulnerable to VBIs due to occupational contact with arthropod vectors, immunological naiveté to previously unencountered pathogens, and limited diagnostic and treatment options available in the austere and unstable environments sometimes associated with military operations. In addition to the risk uniquely encountered by military populations, other factors have driven the worldwide emergence of VBIs. Unprecedented levels of global travel, tourism and trade, and blurred lines of demarcation between zoonotic VBI reservoirs and human populations increase vector exposure. Urban growth in previously undeveloped regions and perturbations in global weather patterns also contribute to the rise of VBIs. The Armed Forces Health Surveillance Center-Global Emerging Infections Surveillance and Response System (AFHSC-GEIS) and its partners at DoD overseas laboratories form a network to better characterize the nature, emergence and growth of VBIs globally. In 2009 the network tested 19,730 specimens from 25 sites for Plasmodium species and malaria drug resistance phenotypes and nearly another 10,000 samples to determine the etiologies of non-Plasmodium species VBIs from regions spanning from Oceania to Africa, South America, and northeast, south and Southeast Asia. This review describes recent VBI-related epidemiological studies conducted by AFHSC-GEIS partner laboratories within the OCONUS DoD laboratory network emphasizing their impact on human populations.
Background: A major concern in malaria vaccine development is genetic polymorphisms typically obs... more Background: A major concern in malaria vaccine development is genetic polymorphisms typically observed among Plasmodium isolates in different geographical areas across the world. Highly polymorphic regions have been observed in Plasmodium falciparum and Plasmodium vivax antigenic surface proteins such as Circumsporozoite protein (CSP), Duffy-binding protein (DBP), Merozoite surface protein-1 (MSP-1), Apical membrane antigen-1 (AMA-1) and Thrombospondin related anonymous protein (TRAP). Methods: Genetic variability was assessed in important polymorphic regions of various vaccine candidate antigens in P. vivax among 106 isolates from the Amazon Region of Loreto, Peru. In addition, genetic diversity determined in Peruvian isolates was compared to population studies from various geographical locations worldwide. Results: The structured diversity found in P. vivax populations did not show a geographic pattern and haplotypes from all gene candidates were distributed worldwide. In addition, evidence of balancing selection was found in polymorphic regions of the trap, dbp and ama-1 genes. Conclusions: It is important to have a good representation of the haplotypes circulating worldwide when implementing a vaccine, regardless of the geographic region of deployment since selective pressure plays an important role in structuring antigen diversity.
Transactions of The Royal Society of Tropical Medicine and Hygiene
Background Anaemia is a public health problem in Peru. In the Loreto region of the Amazon, ≥50% o... more Background Anaemia is a public health problem in Peru. In the Loreto region of the Amazon, ≥50% of children may be anaemic, although insufficient information exists for rural villages. Methods To generate more data about childhood anaemia in the Peruvian Amazon, haemoglobin was measured as part of a trachoma survey in 21 randomly selected villages. All children 1–9 y of age from 30 randomly selected households per village were recruited. Anaemia was classified according to the World Health Organization guidelines and a socio-economic status (SES) index was created for each household using principal component analysis. Spatial autocorrelation was determined using Moran's I and Ripley's K function. Results Of 678 children with complete haemoglobin data, 25.4% (95% confidence interval [CI] 21.2 to 30.1) had mild-or-worse anaemia and 22.1% (95% CI 15.6 to 30.3) had moderate-or-worse anaemia. Mild-or-worse anaemia was more common among children whose primary source of drinking wa...
Objective To determine the relationship between socioeconomic status (SES) and visual impairment ... more Objective To determine the relationship between socioeconomic status (SES) and visual impairment (VI) or blindness in the rural Peruvian Amazon, hypothesizing that higher SES would have a protective effect on the odds of VI or blindness. Methods In this cross-sectional study of 16 rural communities in the Peruvian Amazon, consenting adults aged ≥ 50 years were recruited from ~30 randomly selected households per village. Each household was administered a questionnaire and had a SES score constructed using principal components analysis. Blindness and VI were determined using a ministry of health 3-meter visual acuity card. Results Overall, 207 adults aged ≥ 50 were eligible; 146 (70.5%) completed visual acuity screening and answered the questionnaire. Of those 146 participants who completed presenting visual acuity screening, 57 (39.0%, 95% CI 30.2–47.1) were classified as visually impaired and 6 (4.1%, 95% CI 0.9–7.3) as blind. Belonging to the highest SES tercile had a protective ef...
Sr. Editor, Hemos leído atentamente los comentarios al artículo titulado “Frecuencia elevada de d... more Sr. Editor, Hemos leído atentamente los comentarios al artículo titulado “Frecuencia elevada de dengue grave durante la epidemia por el Linaje II del DENV-2 americano/asiático en el Perú” (1), publicados en su prestigiosa revista. Agradecemos el interés por el mismo y hacemos algunas precisiones.
Background A major concern in malaria vaccine development is genetic polymorphisms typically obse... more Background A major concern in malaria vaccine development is genetic polymorphisms typically observed among Plasmodium isolates in different geographical areas across the world. Highly polymorphic regions have been observed in Plasmodium falciparum and Plasmodium vivax antigenic surface proteins such as Circumsporozoite protein (CSP), Duffy-binding protein (DBP), Merozoite surface protein-1 (MSP-1), Apical membrane antigen-1 (AMA-1) and Thrombospondin related anonymous protein (TRAP). Methods Genetic variability was assessed in important polymorphic regions of various vaccine candidate antigens in P. vivax among 106 isolates from the Amazon Region of Loreto, Peru. In addition, genetic diversity determined in Peruvian isolates was compared to population studies from various geographical locations worldwide. Results The structured diversity found in P. vivax populations did not show a geographic pattern and haplotypes from all gene candidates were distributed worldwide. In addition, e...
Introducción. El ingreso del linaje II del DENV-2 americano/asiático en la región Loreto de la Am... more Introducción. El ingreso del linaje II del DENV-2 americano/asiático en la región Loreto de la Amazonia Peruana, coincidió con un incremento súbito de los casos de dengue con necesidad de hospitalización. Sin embargo, las estadísticas oficiales reportaron pocos casos graves. Se postula, que existió una subnotificación de los casos graves en los reportes oficiales del Ministerio de Salud. Objetivos. Conocer la frecuencia de pacientes con signos de gravedad entre los pacientes hospitalizados por dengue probable durante el brote del 2011 en el Hospital Iquitos, Perú. Métodos. Se realizó un estudio longitudinal, aplicando una lista de chequeo diaria, sobre la presencia de signos de gravedad durante la estancia hospitalaria, a un grupo de pacientes hospitalizados en la unidad de dengue del Hospital Iquitos. Resultados. De 178 pacientes evaluados 66 (37%, IC: 29,9 – 44,6%) presentaron algún signo de gravedad, la mayor parte por shock (75,7%). Este resultado contrasta con el número de paci...
Background: Malaria in Peru is concentrated in the Amazon region, especially in Loreto, and trans... more Background: Malaria in Peru is concentrated in the Amazon region, especially in Loreto, and transmission is focused in rural and peri-urban communities. The government has approved a malaria elimination plan with a community approach and seeks to reduce the risk of transmission through preventive interventions, but asymptomatic and low-parasite-density infections are challenges for disease control and elimination. IgG antibodies play a critical role in combating infection through their ability to reduce parasitaemia and clinical symptoms. In particular, IgG subclasses have important roles in controlling malaria disease and may provide new insight into the development of malaria control strategies and understanding of malaria transmission. Through the use of excreted-secreted antigens from Plasmodium falciparum, were evaluated the responses of the four IgG subclasses in symptomatic and asymptomatic malarial infections. Results: Higher levels of whole IgG were observed in asymptomatic carriers (P < 0.05). IgG3 and IgG1 were the most prevalent subclasses and did not show differences in their antibody levels in either type of carrier. All symptomatic carriers were positive for IgG4, and the presence of IgG3 and IgG2 were correlated with protection against parasitaemia. IgG2 showed lower prevalence and antibody titers in comparison to other subclasses. Conclusions: This is the first study that characterizes the IgG subclass response in the Peruvian Amazon, and these results show that even in populations from regions with low malaria transmission, a certain degree of naturally acquired immunity can develop when the right antibody subclasses are produced. This provides important insight into the potential mechanisms regulating protective immunity.
Revista Peruana de Medicina Experimental y Salud Pública, 2011
We conducted a clinical description of confirmed dengue cases admitted to the Hospital " César Ga... more We conducted a clinical description of confirmed dengue cases admitted to the Hospital " César Garayar García" in Iquitos from January 25 to February 5, 2011. According to current WHO classification, major warning signs leading to hospitalization were: abdominal pain (28/28) and persistent vomiting (15/28), the causes of severity were: hypotension (9 / 13), severe bleeding (6 / 13) and plasma extravasation with respiratory distress (4 / 13). The median patient age was 22 years, however, 8 / 13 patients classified as severe dengue were under 16 years. In conclusion, unlike previous epidemics, we found a high involvement of young people and severity in the clinical presentation predominating a high frequency of shock (hypotension) and vascular leakage, which could be related to the circulation of an emerging variant DENV-2 which is more virulent.
Severe malaria caused by Plasmodium vivax is no longer considered rare. To describe its clinical ... more 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.
Revista Peruana de Medicina Experimental y Salud Pública, 2004
Objetivos: Como respuesta a la emergencia de la resistencia del P. falciparum a los antimaláricos... more Objetivos: Como respuesta a la emergencia de la resistencia del P. falciparum a los antimaláricos, el Ministerio de Salud del Perú decidió adoptar los esquemas de tratamiento para malaria combinados recomendados por la OMS: MQ-AS y SP-AS, pero el costo de la nueva terapia es significativamente superior a los anteriores esquemas; SP y quinina + tetraciclina, sin embargo tendría como ventaja una mayor eficacia y probablemente la capacidad de disminuir la transmisión. Por estos motivos se evaluó de manera prospectiva el costo efectividad del cambio en los esquemas de tratamiento para malaria. Materiales y métodos: Se uso el método de análisis de decisiones y de riesgos, se construyó un modelo probabilística que estableció las relaciones formales entre diversos factores que van a modificar el número de casos, muertes, los años de vida ajustados por discapacidad (AVAD) y los costos del programa en un periodo de cinco años. Resultados: Se halló que si bien el costo unitario por tratamient...
Outdoor malaria transmission hinders malaria elimination efforts in the Amazon region and novel v... more Outdoor malaria transmission hinders malaria elimination efforts in the Amazon region and novel vector control tools are needed. Ivermectin mass drug administration (MDA) to humans kills wild Anopheles, targets outdoor-feeding vectors, and can suppress malaria parasite transmission. Laboratory investigations were performed to determine ivermectin susceptibility, sporontocidal effect and inhibition of time to re-feed for the primary Amazonian malaria vector, Anopheles darlingi. To assess ivermectin susceptibility, various concentrations of ivermectin were mixed in human blood and fed to An. darlingi. Mosquito survival was monitored daily for 7 days and a non-linear mixed effects model with Probit analysis was used to calculate lethal concentrations of ivermectin that killed 50% (LC50), 25% (LC25) and 5% (LC5) of mosquitoes. To examine ivermectin sporonticidal effect, Plasmodium vivax blood samples were collected from malaria patients and offered to mosquitoes without or with ivermect...
Severe malaria caused by Plasmodium vivax is no longer considered rare. To describe its clinical ... more 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.
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