Is there malaria transmission in urban settings in Colombia?

Abstract

BackgroundColombia contributes a significant proportion of malaria cases in the Americas, which are predominantly rural. However, in the last 8 years ~ 10 % of the endemic municipalities have also reported urban and peri-urban malaria cases, a growing concern for health authorities. This study focused on the characterization of the officially reported urban malaria cases.MethodsA descriptive retrospective study based on secondary information provided by the Colombian National Surveillance System-SIVIGILA for the 2008–2012 period was conducted. A total of 17 municipalities with consistent and persistent reports of urban and peri-urban malaria were selected for analysis, which included site of origin and of residence, age, gender and ethnicity of patients, health system affiliation, Plasmodium species and the presence of malaria vectors.ResultsA total of 18,113 malaria cases were reported from urban and peri-urban areas of 17 endemic municipalities. Almost 70 % of the reports originated in localities in the departments of Chocó and Nariño, located on the Pacific Coast where a predominantly Afro-Colombian population, of individuals of under 30 years of age, was the most affected (80.7 %), mainly with Plasmodium falciparum infections (52.1 %). Median annual parasite index (API) was 6.4 per 1000 inhabitants (3.4 in 2008; 10.8 in 2010 and 6.0 in 2012). Between 2011 and 2012 complicated cases (2.4 %) and malaria in pregnant women (1.4 %) were reported. Study areas reported the presence of at least seven Anopheles species considered malaria vectors. These analyses did not allow ascertaining the presumable origin of the recorded urban cases due to the lack of a consensus on a definition of urban, peri-urban and rural limits and the lack of proper verification of the geographical source of infection.ConclusionsThe study indicates the probable presence of endemic, unstable and low-intensity malaria transmission in Colombian urban and peri-urban areas of a group of municipalities located mainly on the Pacific coast region and a few others in the eastern region. There is a need to unequivocally confirm the urban or peri-urban origin of the malaria cases reported and the transmission conditions, as well as to develop and implement new strategies for urban and peri-urban malaria control and elimination.

Molecular evidence of sustained urban malaria transmission in Amazonian Brazil, 2014–2015

“…Malaria rates tend to be lower in cities and towns compared with neighbouring rural settings, due to multiple factors such as improved housing and access to healthcare and limited availability of suitable vector-breeding habitats [2]. Nevertheless, malaria cases have been increasingly reported within and near urban centres across the Amazon Basin [3][4][5][6][7] and the Pacific Coast of South America [8][9][10][11][12][13].…”

Epidemiología de las principales enfermedades transmitidas por vectores en Colombia, 1990-2016

“…Se consideró como caso de malaria urbana o periurbana aquel caso confirmado en un área urbana o periurbana (definida según los planes oficiales de ordenamiento municipal) en el que se hubiera demostrado el origen autóctono de la transmisión (32).…”

La Región “Urabá Antioqueño-Cuencas altas de los ríos Sinú y San Jorge-Bajo Cauca Antioqueño”: “guarida” del paludismo colombiano

“…"Centro poblado" es un "concepto creado por el DANE para fines estadísticos, útil para la identificación de núcleos de población. La revisión retrospectiva del sistema de información epidemiológica (Sivigila), entre 2008 y 2012, permitió identificar 17 municipios con "informes consistentes y persistentes de malaria urbana y periurbana", así: 13 en la Región del Pacífico, otros cuatro dispersos, y Puerto Nariño, Amazonas 16 . Según los autores, a pesar de que se trata de informes persistentes y consistentes, "los análisis no permiten asegurar el origen presumible de casos ocurridos en la zona urbana debido a la falta de consenso sobre la definición de los límites de urbano, periurbano y rural y la falta de verificación apropiada de la fuente geográfica de la infección" 16 .…”

“…La revisión retrospectiva del sistema de información epidemiológica (Sivigila), entre 2008 y 2012, permitió identificar 17 municipios con "informes consistentes y persistentes de malaria urbana y periurbana", así: 13 en la Región del Pacífico, otros cuatro dispersos, y Puerto Nariño, Amazonas 16 . Según los autores, a pesar de que se trata de informes persistentes y consistentes, "los análisis no permiten asegurar el origen presumible de casos ocurridos en la zona urbana debido a la falta de consenso sobre la definición de los límites de urbano, periurbano y rural y la falta de verificación apropiada de la fuente geográfica de la infección" 16 . Técnicamente puede ser correcta tal apreciación (los límites no están ni estarán definidos, porque son cambiantes), pero no me quedan dudas sobre la existencia de malaria urbana-periurbana en esos y otros municipios del país, con base en el citado estudio y en otros informes [17][18][19][20] .…”