Malaria en la región eco-epidemiológica del Caribe Colombiano, 1960-2019 / Malaria in the eco-epidemiological region of the Colombian Caribbean, 1960-2019

La malaria en Colombia tiene un comportamiento heterogéneo y variable, entre las regiones. Para establecer su comportamiento epidemiológico en la región del Caribe colombiano entre 1960 y 2019 se realizó un estudio observacional, descriptivo y retrospectivo a partir de registros del Ministerio de Salud y otras fuentes secundarias. Se definieron variables epidemiológicas y se elaboraron medidas de frecuencia y tendencia central. Se registraron 155 096 casos. Las décadas con mayor número de casos fueron 1990-1999 (20,5%) y 1980-1989 (18,9%). El promedio de casos por década fue de 25 849,3. Los índices parasitarios más elevados se registraron en 1970 (3,3 por 1000 habitantes) y 1981 (3,9 por 1000 habitantes). La especie Plasmodium vivax fue la más frecuente y la mayoría de la carga por grupos de edad se registró en menores de 29 años, entre 2010-2019. La malaria presentó un patrón endemo-epidémico de baja y muy baja intensidad de transmisión, con una tendencia al descenso.

Malaria has a heterogeneous and variable behavior among Colombian regions. In order to establish its epidemiological behavior in the Colombian Caribbean region between 1960 and 2019, we carried out an observational, descriptive and retrospective study based on records from the Ministry of Health and other secondary sources. We defined epidemiological variables and used measures of frequency and central tendency. A total of 155,096 cases were registered. The decades with the highest number of cases were 1990-1999 (20.5%) and 1980-1989 (18.9%). The average number of cases per decade was 25,849.3. The highest parasite rates were recorded in 1970 (3.3 per 1000 population) and 1981 (3.9 per 1000 population). Plasmodium vivax was the most frequent species and most of the burden by age group was found in people under 29 years of age, between 2010-2019. Malaria showed an endemic-epidemic pattern of low and very low transmission intensity, with a decreasing trend.

The malaria eradication campaign in Colombia, 1959-1979 / La campaña de erradicación de la malaria en Colombia, 1959-1979

Introduction: In the mid-fifties, Colombia adopted and implemented the Malaria Eradication Campaign (MEC), which has not been evaluated yet in the country. Objective: To evaluate the results achieved during the attack and consolidation phases of the MEC regarding malaria transmission in Colombia between 1959 and 1979. Materials and methods: We conducted a descriptive and retrospective study based on the malariometric and operational results of the MEC in Colombia from 1959 to 1979 compiled from the archives of the Ministry of Public Health. We used the criteria defined by the WHO Expert Committee on Malaria. The information was stored, tabulated, and analyzed based on the malariometric indicators we developed. Results: In the short-term eradication period (1959-1969), a reduction of 94% (4,172) in transmission was achieved during the first year of the attack phase (1959) while in the last year (1962), there was an 88% (8,426) reduction of the accumulated load of cases compared to the annual average of the 1950s (71,031). These low levels of transmission were maintained until the end of 1969. During the intensification period of control of the eradication (1970-1979), there was an increase in malaria endemicity and a resurgence of the epidemic transmission. Due to financial problems affecting the regularity of the operations, Colombia was unable to sustain the results and achieve an interruption of transmission, which resulted in a resurgence of cases during the attack and consolidation phases. Conclusions: The campaign did not achieve the goal of interrupting malaria transmission in the national territory but there was marked control in areas of medium and low intensity.

Introducción. A mediados de la década de 1950, el país adoptó e implementó la Campaña de Erradicación de la Malaria (CEM), sin que hasta ahora se haya hecho su evaluación. Objetivo. Evaluar los resultados alcanzados en las fases de ataque y consolidación de la campaña de erradicación de la malaria en Colombia, entre 1959 y 1979. Materiales y métodos. Se hizo un estudio descriptivo y retrospectivo de los resultados "malariométricos" y operacionales de la CEM en Colombia entre 1959 y 1979 a partir de los datos recopilados de los archivos del Ministerio de Salud Pública. Se utilizaron los criterios establecidos por la Organización Mundial de la Salud (OMS) relacionados con las fases de un programa de erradicación de malaria. Se almacenó, tabuló y analizó la información, y se elaboraron y aplicaron indicadores malariométricos. Resultados. En el periodo de erradicación a corto plazo (1959-1969), durante el primer año de la fase de ataque (1959), se alcanzó una reducción de la transmisión del 94 % (4.172) y, en el último año (1962), una disminución del 88 % (8.426) en la carga acumulada de casos comparada con el promedio anual de la década del 50 (71.031); estos bajos niveles de transmisión se mantuvieron hasta finales de 1969. En el periodo de intensificación del control para la erradicación (1970-1979), se produjo un incremento de la endemia y resurgió la transmisión epidémica. Debido a problemas financieros que afectaron la regularidad de la operación para mantener los resultados, y no habiéndose logrado la interrupción de la transmisión, se observó un resurgimiento de casos en las fases de ataque y consolidación. Conclusiones. La campaña no logró la meta de interrupción de la transmisión de la malaria en el territorio nacional, pero sí se consiguió un acentuado control en áreas de mediana y baja intensidad.

Epidemiological evolution and historical anti-malarial control initiatives in Colombia, 1848-2019.

The evolution of epidemiological transmission and the control measures implemented in Colombia have been the result of complex global and regional economic and political processes that occurred at different historical moments, since the dawn of the country's republican life. The development of economic activities for the production, exploitation and export of agricultural products, minerals and raw materials demanded in the international market, favored the necessary conditions for the emergence, expansion, resurgence and persistence of the endemic epidemic of malaria in the different stages studied. A common and fundamental element in the different defined historical moments was the importance given to malaria as an economic problem due to the negative externalities it imposed on the labor force. In addition, due to the role it played as a barrier that limited the exploitation of natural resources and raw materials of interest; as well as the impact that it caused to the flow and commercial exchange. The previous situation was framed with the growth, consolidation and geostrategic expansion of the United States, as the main commercial partner of the region, and its interest in the exploitation of resources and raw materials, cheap labor, the need to create new markets, which coincided with the goals of modernization and economic strengthening of Colombia. Taking into account different relevant milestones that occurred in the 1848-2019 period, the following stages were defined: Epidemiological emergence and re-emergence of tropical fevers in places of economic exploitation, 1848-1899;Emergence of a new paradigm, control in enclaves of economic interest, ports and cities, 1900-1949;Control to eradication, intensified control-eradication, prevention and control, 1950-1999;Prevention, control and elimination of malaria, 2000-2019. Historically, antimalarial control initiatives in the country have been directed, restricted and prioritized in places of political and economic importance. The technical-scientific intervention measures implemented in the different stages studied have been uncritically replicated without adapting to the epidemiological scenarios existing in the country. Finally, the antimalarial control measures implemented in Colombia have been imported and adopted from international health initiatives as a result of commitments and obligations acquired in the global commercial context.

La campaña de erradicación de la malaria en Colombia, 1959-1979 / The malaria eradication campaign in Colombia, 1959-1979

Introducción. A mediados de la década de 1950, el país adoptó e implementó la Campaña de Erradicación de la Malaria (CEM), sin que hasta ahora se haya hecho su evaluación. Objetivo. Evaluar los resultados alcanzados en las fases de ataque y consolidación de la campaña de erradicación de la malaria en Colombia, entre 1959 y 1979. Materiales y métodos. Se hizo un estudio descriptivo y retrospectivo de los resultados "malariométricos" y operacionales de la CEM en Colombia entre 1959 y 1979 a partir de los datos recopilados de los archivos del Ministerio de Salud Pública. Se utilizaron los criterios establecidos por la Organización Mundial de la Salud (OMS) relacionados con las fases de un programa de erradicación de malaria. Se almacenó, tabuló y analizó la información, y se elaboraron y aplicaron indicadores malariométricos. Resultados. En el periodo de erradicación a corto plazo (1959-1969), durante el primer año de la fase de ataque (1959), se alcanzó una reducción de la transmisión del 94 % (4.172) y, en el último año (1962), una disminución del 88 % (8.426) en la carga acumulada de casos comparada con el promedio anual de la década del 50 (71.031); estos bajos niveles de transmisión se mantuvieron hasta finales de 1969. En el periodo de intensificación del control para la erradicación (1970-1979), se produjo un incremento de la endemia y resurgió la transmisión epidémica. Debido a problemas financieros que afectaron la regularidad de la operación para mantener los resultados, y no habiéndose logrado la interrupción de la transmisión, se observó un resurgimiento de casos en las fases de ataque y consolidación. Conclusiones. La campaña no logró la meta de interrupción de la transmisión de la malaria en el territorio nacional, pero sí se consiguió un acentuado control en áreas de mediana y baja intensidad.

Introduction: In the mid-fifties, Colombia adopted and implemented the Malaria Eradication Campaign (MEC), which has not been evaluated yet in the country. Objective: To evaluate the results achieved during the attack and consolidation phases of the MEC regarding malaria transmission in Colombia between 1959 and 1979. Materials and methods: We conducted a descriptive and retrospective study based on the malariometric and operational results of the MEC in Colombia from 1959 to 1979 compiled from the archives of the Ministry of Public Health. We used the criteria defined by the WHO Expert Committee on Malaria. The information was stored, tabulated, and analyzed based on the malariometric indicators we developed. Results: In the short-term eradication period (1959-1969), a reduction of 94% (4,172) in transmission was achieved during the first year of the attack phase (1959) while in the last year (1962), there was an 88% (8,426) reduction of the accumulated load of cases compared to the annual average of the 1950s (71,031). These low levels of transmission were maintained until the end of 1969. During the intensification period of control of the eradication (1970-1979), there was an increase in malaria endemicity and a resurgence of the epidemic transmission. Due to financial problems affecting the regularity of the operations, Colombia was unable to sustain the results and achieve an interruption of transmission, which resulted in a resurgence of cases during the attack and consolidation phases. Conclusions: The campaign did not achieve the goal of interrupting malaria transmission in the national territory but there was marked control in areas of medium and low intensity.

Malaria in the eco-epidemiological region of the Colombian Caribbean, 1960-2019. / Malaria en la región eco-epidemiológica del Caribe Colombiano, 1960-2019.

OBJECTIVES.: Motivation for the study: the information available on the epidemiology of malaria in the Colombian Caribbean region is incomplete, poorly systematized and its dissemination is limited. This has led to a lack of knowledge of its magnitude and a low perception of its importance as a public health problem. Main findings: the behavior of malaria is endemic-epidemic, with low to very low transmission, focused and with irregular outbreaks. Plasmodium vivax infections predominate. Implications: the results of this study contribute to improve evidence-based decision making for the implementation of malaria eradication plans. Malaria has a heterogeneous and variable behavior among Colombian regions. In order to establish its epidemiological behavior in the Colombian Caribbean region between 1960 and 2019, we carried out an observational, descriptive and retrospective study based on records from the Ministry of Health and other secondary sources. We defined epidemiological variables and used measures of frequency and central tendency. A total of 155,096 cases were registered. The decades with the highest number of cases were 1990-1999 (20.5%) and 1980-1989 (18.9%). The average number of cases per decade was 25,849.3. The highest parasite rates were recorded in 1970 (3.3 per 1000 population) and 1981 (3.9 per 1000 population). Plasmodium vivax was the most frequent species and most of the burden by age group was found in people under 29 years of age, between 2010-2019. Malaria showed an endemic-epidemic pattern of low and very low transmission intensity, with a decreasing trend.

OBJETIVOS.: Motivación para realizar el estudio: la información disponible sobre la epidemiología de la malaria en la región del Caribe colombiano está incompleta, poco sistematizada y su divulgación es limitada. Esto ha generado un desconocimiento en su magnitud y una baja percepción de su importancia como problema de salud pública. Principales hallazgos: el comportamiento de la malaria es endemo-epidémico, de baja a muy baja transmisión, focalizado y con aparición de brotes irregulares. Predominan las infecciones por Plasmodium vivax. Implicancias: los resultados este estudio contribuyen a mejorar la toma de decisiones basadas en evidencia, para la ejecución de planes de eliminación de la malaria. La malaria en Colombia tiene un comportamiento heterogéneo y variable, entre las regiones. Para establecer su comportamiento epidemiológico en la región del Caribe colombiano entre 1960 y 2019 se realizó un estudio observacional, descriptivo y retrospectivo a partir de registros del Ministerio de Salud y otras fuentes secundarias. Se definieron variables epidemiológicas y se elaboraron medidas de frecuencia y tendencia central. Se registraron 155 096 casos. Las décadas con mayor número de casos fueron 1990-1999 (20,5%) y 1980-1989 (18,9%). El promedio de casos por década fue de 25 849,3. Los índices parasitarios más elevados se registraron en 1970 (3,3 por 1000 habitantes) y 1981 (3,9 por 1000 habitantes). La especie Plasmodium vivax fue la más frecuente y la mayoría de la carga por grupos de edad se registró en menores de 29 años, entre 2010-2019. La malaria presentó un patrón endemo-epidémico de baja y muy baja intensidad de transmisión, con una tendencia al descenso.

Malaria risk stratification in Colombia 2010 to 2019.

BACKGROUND: Heterogeneity and focalization are the most common epidemiological characteristics of endemic countries in the Americas, where malaria transmission is moderate and low. During malaria elimination, the first step is to perform a risk stratification exercise to prioritize interventions. This study aimed to identify malaria risk strata in the ecoepidemiological regions of Colombia. METHODS: This was a descriptive and retrospective study using cumulative malaria cases in 1,122 municipalities of Colombia from 2010 to 2019. To identify the strata, the criteria proposed by PAHO were adapted. To classify the receptive areas (strata 2, 3, and 4) and nonreceptive areas (stratum 1), 1,600 m above sea level, ecotypes, main malaria vector presence, Plasmodium species prevalence and occurrence of malaria cases were used. The area occupied by the receptive municipalities, the cumulative burden, and the at-risk population in the regions were calculated. RESULTS: Ninety-one percent of the Colombian territory is receptive to the transmission of malaria and includes 749 municipalities with 9,734,271 (9,514,243-9,954,299) million at-risk inhabitants. Stratum 4 accounted for 96.7% of the malaria burden, and cases were concentrated primarily in the Pacific and Uraba-Bajo Cauca-Sinu-San Jorge regions. Plasmodium vivax predominates in most of the receptive municipalities, except in the municipalities of the Pacific region, where P. falciparum predominates. Anopheles albimanus, An. nuneztovari s.l., and An. darlingi were the main vectors in receptive areas. CONCLUSIONS: In Colombia, 91.2% of the territory is receptive to the transmission of malaria and is characterized by being both heterogeneous and focused. Stratum 4 contains the greatest burden of disease, with a relatively greater proportion of municipalities with a predominance of P. vivax. However, there is a low proportion of municipalities with P. falciparum mainly in the Pacific region. These findings suggest that the latter be prioritized within the malaria elimination plan in Colombia.

Parasite density in severe malaria in Colombia.

BACKGROUND: Colombia has officially adopted the parasite density levels of severe malaria established by the WHO (>50,000 parasites/µl). These values have been inferred from areas of high transmission in Africa and are not consistent with the dynamics of low and unstable transmission in Colombia. The objective of this study was therefore to determine the parasite density values observed in patients with severe malaria and their distribution in the different ecoepidemiological regions of Colombia. METHODS: A retrospective and descriptive study of confirmed cases of severe malaria was conducted in endemic areas of malaria in Colombia over the period 2014-2017. Data were collected from secondary sources of the Subnational Programs of Malaria Prevention and Control. Person, place, and time variables were selected. The official definition of severe malaria was adopted, and compliance with these criteria was determined. Univariate and bivariate analyses were conducted with absolute and relative frequency measures, and the relevant statistical tests were applied. RESULTS: The overall parasite density values in Colombia showed a geometric mean of 5,919 parasites/µl (95% CI: 5,608-6,248). By parasite species, the values were 6,151 (95% CI: 5,631-6,718) for Plasmodium falciparum and 5,815 (95% CI: 5,428-6,230) for Plasmodium vivax. The highest parasite density values were recorded in the Amazon ecoepidemiological region (8,177; 95% CI: 6,015-11,116), and the lowest values were recorded in the Andean region (5,026; 95% CI: 2,409-10,480). CONCLUSIONS: In endemic areas of low and unstable malaria transmission in the Colombian territory, the parasite density levels observed in populations with severe malaria are lower than the officially established values. The parasite density criterion is not really a relevant criterion for the definition of severe cases in Colombia and it certainly not be used to make a clinical decision about the severity of the disease.