Epidemic and Non-Epidemic Hot Spots of Malaria Transmission Occur in Indigenous Comarcas of Panama

Abstract

From 2002–2005, Panama experienced a malaria epidemic that has been associated with El Niño Southern Oscillation weather patterns, decreased funding for malaria control, and landscape modification. Case numbers quickly decreased afterward, and Panama is now in the pre-elimination stage of malaria eradication. To achieve this new goal, the characterization of epidemiological risk factors, foci of transmission, and important anopheline vectors is needed. Of the 24,681 reported cases in these analyses (2000–2014), ~62% occurred in epidemic years and ~44% in indigenous comarcas (5.9% of Panama’s population). Sub-analyses comparing overall numbers of cases in epidemic and non-epidemic years identified females, comarcas and some 5-year age categories as those disproportionately affected by malaria during epidemic years. Annual parasites indices (APIs; number of cases per 1,000 persons) for Plasmodium vivax were higher in comarcas compared to provinces for all study years, though P. falciparum APIs were only higher in comarcas during epidemic years. Interestingly, two comarcas report increasing numbers of cases annually, despite national annual decreases. Inclusion of these comarcas within identified foci of malaria transmission confirmed their roles in continued transmission. Comparison of species distribution models for two important anophelines with Plasmodium case distribution suggest An. albimanus is the primary malaria vector in Panama, confirmed by identification of nine P. vivax-infected specimen pools. Future malaria eradication strategies in Panama should focus on indigenous comarcas and include both active surveillance for cases and comprehensive anopheline vector surveys.

Natural Malaria Infection in Anopheline Vectors and Their Incrimination in Local Malaria Transmission in Darién, Panama

“…(Ano.) punctimacula s. l. (through PCR assays) collected in Bocas del Toro province [71]. In another study it was detected by PCR An.…”

“…(Nys.) albimanus collected from 2006-2007 in Bocas del Toro, Panama, nine pools were detected naturally infected with P. vivax by an ELISA test (three pools with the VK210 variant and six with the VK247 variant) [71].…”

Long-term Transmission Patterns and Public Health Policies Leading to Malaria Elimination in Panamá

“…This crucial obstacle has been previously identified in several studies and reports from indigenous communities in Panama [9,10,70,71], but remains a neglected issue to be solved. In this line, it is important to improve health services and reduced socioeconomical disparities in the indigenous reservations, precisely where malaria transmission persists [11,14]. At present, poverty prevails in these rural inhabited by indigenous groups, where access to health and basic services is limited [11].…”

“…Currently, malaria transmission in Panamá is considered low, and most of the country is free of the disease. However, localized and well identified foci persist, characterized by a seasonal epidemic mainly due to Plasmodium vivax [12,14]. Regarding malaria vectors, several species have been recorded in the Panamá, with Anopheles albimanus and Anopheles punctimacula being the most common and widely distributed across the country [15].…”

Long-term transmission patterns and public health policies leading to malaria elimination in Panamá

“…Currently, malaria transmission in Panamá is considered low, and most of the country is free of the disease. However, localized and well identi ed foci persist, characterized by a seasonal epidemic mainly due to P. vivax [12,14]. Regarding malaria vectors, several species have been recorded in the Panamá, with Anopheles albimanus and Anopheles punctimacula being the most common and widely distributed across the country [15,16].…”