Anopheles albimanus (Diptera: Culicidae) Ensemble Distribution Modeling: Applications for Malaria Elimination.

In the absence of entomological information, tools for predicting Anopheles spp. presence can help evaluate the entomological risk of malaria transmission. Here, we illustrate how species distribution models (SDM) could quantify potential dominant vector species presence in malaria elimination settings. We fitted a 250 m resolution ensemble SDM for Anopheles albimanus Wiedemann. The ensemble SDM included predictions based on seven different algorithms, 110 occurrence records and 70 model projections. SDM covariates included nine environmental variables that were selected based on their importance from an original set of 28 layers that included remotely and spatially interpolated locally measured variables for the land surface of Costa Rica. Goodness of fit for the ensemble SDM was very high, with a minimum AUC of 0.79. We used the resulting ensemble SDM to evaluate differences in habitat suitability (HS) between commercial plantations and surrounding landscapes, finding a higher HS in pineapple and oil palm plantations, suggestive of An. albimanus presence, than in surrounding landscapes. The ensemble SDM suggested a low HS for An. albimanus at the presumed epicenter of malaria transmission during 2018-2019 in Costa Rica, yet this vector was likely present at the two main towns also affected by the epidemic. Our results illustrate how ensemble SDMs in malaria elimination settings can provide information that could help to improve vector surveillance and control.

Factores de riesgo asociados con la leishmaniasis cutánea en dos comunidades rurales de Panamá Oeste

Introducción: La leishmaniasis cutánea (LC) es una enfermedad zoonótica endémica en Panamá. Su agente causal son protozoarios del género Leishmania y la transmiten insectos flebotominos. Objetivo: Evaluar los factores de riesgos asociados con la LC y la diversidad de flebotominos en dos comunidades rurales de Panamá Oeste. Metodología: Se seleccionaron dos comunidades endémicas para LC: Trinidad de las Minas (TM), de alta incidencia y Las Pavas (LP), de baja incidencia. Los factores de riesgo asociados con la LC fueron evaluados mediante una encuesta aplicada a100 personas (TM: n=50; LP: n=50). Se colectaron flebotominos con trampas CDC durante tres noches consecutivas en temporada lluviosa y seca. Resultados: La mayoría de las personas confirmó conocer sobre la LC (TM: 96% y LP: 68%). No se encontraron diferencias significativas entre las características sociodemográficas, estructura de las viviendas, composición del peridomicilio y abundancia/diversidad de animales domésticos en ambas comunidades. El reporte de perezosos cercanos al peridomicilio fue mayor en TM (70%) vs LP (32%). La especie de flebotomino antropofílica más abundante durante la temporada seca fue Lutzomyia gomezi (TM: 40.1% y LP: 10.4%). Durante la temporada lluviosa fue Nyssomyia trapidoi (43.4%) en TM y Psychodopygus panamensis (75.7%) en LP. Las especies zoofílicas más comunes en ambas comunidades fueron Trichopygomyia triramula y Pressatia dysponeta. Conclusión: La mayor incidencia de LC en TM podría estar condicionada a su ecología montañosa, con una cobertura boscosa cercana más extensa y una mayor frecuencia de mamíferos reservorios silvestres. Se confirmó la presencia de vectores de LC en el peridomicilio de ambas comunidades. (provisto por Infomedic International)

Introduction: Cutaneous leishmaniasis (CL) is a zoonotic disease endemic in Panama. Its causal agent are protozoa of the genus Leishmania and is transmitted by phlebotomine sandflies. Objective: To evaluate the risk factors associated with CL and the diversity of phlebotomine sandflies in two rural communities in western Panama. Methodology: Two CL endemic communities were selected: Trinidad de las Minas (TM), with high incidence and Las Pavas (LP), with low incidence. The risk factors associated with CL were assessed by means of a survey applied to 100 people (TM: n=50; LP: n=50). Phlebotomine sandflies were collected with CDC traps during three consecutive nights in rainy and dry season. Results: The majority of people confirmed knowledge about CL (TM: 96% and LP: 68%). No significant differences were found between sociodemographic characteristics, housing structure, peridomicile composition and abundance/diversity of domestic animals in both communities. The report of sloths near the peridomicile was higher in TM (70%) vs LP (32%). The most abundant anthropophilic phlebotomine species during the dry season was Lutzomyia gomezi (TM: 40.1% and LP: 10.4%). During the rainy season it was Nyssomyia trapidoi (43.4%) in TM and Psychodopygus panamensis (75.7%) in LP. The most common zoophilic species in both communities were Trichopygomyia triramula and Pressatia dysponeta. Conclusion: The higher incidence of CL in TM could be conditioned to its mountainous ecology, with a more extensive nearby forest cover and a higher frequency of wild mammal reservoirs. The presence of CL vectors in the peridomicile of both communities was confirmed. (provided by Infomedic International)

Malaria infection rates in Anopheles albimanus (Diptera: Culicidae) at Ipetí-Guna, a village within a region targeted for malaria elimination in Panamá.

The Panamá Canal construction encompassed one of the first examples of malaria elimination. Nevertheless, malaria has uninterruptedly persisted in Native American populations living within a few kilometers of the Panamá Canal. Here, we present results from a monthly longitudinal study (May 2016 to March 2018), whose goal was to quantitatively describe seasonal patterns of Plasmodium spp. infection in Anopheles albimanus Wiedemann, and its association with environmental covariates, at Ipetí-Guna, a village within a region targeted for malaria elimination in Panamá. To detect Plasmodium spp. infections we employed a standard nested PCR on DNA extracts from mosquito pools of varying size, which were then used to estimate monthly infection rates using a maximum likelihood method. The infection rate estimates (IR) were analyzed using time series analysis methods to study their association with changes in rainfall, temperature, NDVI (a satellite derived vegetation index), malaria cases and human biting rates (HBR). We found that mosquitoes were infected by Plasmodium vivax mainly from September to December, reaching a peak in December. Time series modeling showed malaria IR in An albimanus increased, simultaneously with HBR, and IR in the previous month. These results suggest that elimination interventions, such as mass drug administration, are likely to be more effective if deployed from the middle to the end of the dry season (March and April at Ipetí-Guna), when the likelihood of malaria infection in mosquitoes is very low and when curtailing human infections driving infections in mosquitoes can reduce malaria transmission, and increase the chance for elimination.

Leishmania spp. Infection Rate and Feeding Patterns of Sand Flies (Diptera: Psychodidae) from a Hyperendemic Cutaneous Leishmaniasis Community in Panamá.

American cutaneous leishmaniasis (ACL) is a common and important vector-borne parasitic zoonosis in Panamá. Here, we study Leishmania spp. infection rates and blood-feeding patterns among common sand flies in Trinidad de Las Minas, a rural community with hyperendemic ACL transmission, and where a deltamethrin fogging trial was performed. Sand flies were collected from April 2010 to June 2011 with light traps installed inside and in the peridomicile of 24 houses. We restricted our analysis to the most abundant species at the study site: Lutzomyia trapidoi, Lutzomyia gomezi, Lutzomyia panamensis, Lutzomyia triramula, and Lutzomyia dysponeta. We detected Leishmania spp. infection in sand flies by polymerase chain reaction (PCR) amplification of the internal transcribed spacer region 1 (ITS-1) in pooled females (1-10 females per pool). Host species of engorged sand flies were identified using a cytochrome b PCR. From 455 sand fly pools analyzed, 255 pools were positive for Leishmania spp., with an estimated infection rate (confidence interval) of 0.096 [0.080-0.115] before the deltamethrin fogging which slightly, but not significantly (P > 0.05), increased to 0.116 [0.098-0.136] after the deltamethrin fogging. Blood meal analysis suggested that pigs, goats, and birds were the most common sand fly blood sources, followed by humans and domestic dogs. DNA sequencing from a subsample of ITS-1 positive pools suggests that Leishmania panamensis, Leishmania naiffi, and other Leishmania spp. were the parasite species infecting the most common vectors at the study site. Our data confirm an association between sand fly species, humans, domestic dogs, and pigs and Leishmania spp. parasites in rural Panamá.

Population Dynamics of Anopheles albimanus (Diptera: Culicidae) at Ipetí-Guna, a Village in a Region Targeted for Malaria Elimination in Panamá.

Anopheles albimanus Wiedemann is a major malaria vector in Mesoamerica and the Caribbean whose population dynamics, in response to changing environments, has been relatively poorly studied. Here, we present monthly adult and larvae data collected from May 2016 to December 2017 in Ipetí-Guna, a village within an area targeted for malaria elimination in the República de Panamá. During the study period we collected a total of 1678 Anopheles spp. mosquitoes (1602 adults and 76 larvae). Over 95% of the collected Anopheles spp. mosquitoes were An. albimanus. Using time series analysis techniques, we found that population dynamics of larvae and adults were not significantly correlated with each other at any time lag, though correlations were highest at one month lag between larvae and adults and four months lag between adults and larvae. Larvae population dynamics had cycles of three months and were sensitive to changes in temperature with 5 months lag, while adult abundance was correlated with itself (1 month lag) and with the normalized difference vegetation index (NDVI) with three months lag. A key observation from our study is the absence of both larvae and adults of An. albimanus between January and April from environments associated with Guna population's daily activities, which suggests this time window could be the best time to implement elimination campaigns aimed at clearing Plasmodium spp. parasites from Guna populations using, for example, mass drug administration.

Climatic fluctuations and malaria transmission dynamics, prior to elimination, in Guna Yala, República de Panamá.

BACKGROUND: Malaria has historically been entrenched in indigenous populations of the República de Panamá. This scenario occurs despite the fact that successful methods for malaria elimination were developed during the creation of the Panamá Canal. Today, most malaria cases in the República de Panamá affect the Gunas, an indigenous group, which mainly live in autonomous regions of eastern Panamá. Over recent decades several malaria outbreaks have affected the Gunas, and one hypothesis is that such outbreaks could have been exacerbated by climate change, especially by anomalous weather patterns driven by the EL Niño Southern Oscillation (ENSO). RESULTS: Monthly malaria cases in Guna Yala (1998-2016) were autocorrelated up to 2 months of lag, likely reflecting parasite transmission cycles between humans and mosquitoes, and cyclically for periods of 4 months that might reflect relapses of Plasmodium vivax, the dominant malaria parasite transmitted in Panamá. Moreover, malaria case number was positively associated (P < 0.05) with rainfall (7 months of lag), and negatively with the El Niño 4 index (15 months of lag) and the Normalized Difference Vegetation Index, NDVI (8 months of lag), the sign and magnitude of these associations likely related to the impacts of weather patterns and vegetation on the ecology of Anopheles albimanus, the main malaria vector in Guna Yala. Interannual cycles, of approximately 4-year periods, in monthly malaria case numbers were associated with the El Niño 4 index, a climatic index associated with weather and vegetation dynamics in Guna Yala at seasonal and interannual time scales. CONCLUSION: The results showed that ENSO, rainfall and NDVI were associated with the number of malaria cases in Guna Yala during the study period. These results highlight the vulnerability of Guna populations to malaria, an infection sensitive to climate change, and call for further studies about weather impacts on malaria vector ecology, as well as the association of malaria vectors with Gunas paying attention to their socio-economic conditions of poverty and cultural differences as an ethnic minority.

Survey of wild mammal hosts of cutaneous leishmaniasis parasites in panamá and costa rica.

The eco-epidemiology of American cutaneous leishmaniasis (ACL) is driven by animal reservoir species that are a source of infection for sand flies that serve as vectors infecting humans with Leishmania spp parasites. The emergence and re-emergence of this disease across Latin America calls for further studies to identify reservoir species associated with enzootic transmission. Here, we present results from a survey of 52 individuals from 13 wild mammal species at endemic sites in Costa Rica and Panama where ACL mammal hosts have not been previously studied. For Leishmania spp. diagnostics we employed a novel PCR technique using blood samples collected on filter paper. We only found Leishmania spp parasites in one host, the two-toed sloth, Choloepus hoffmanni. Our findings add further support to the role of two-toed sloths as an important ACL reservoir in Central America.

Clinical cutaneous leishmaniasis rates are associated with household Lutzomyia gomezi, Lu. Panamensis, and Lu. trapidoi abundance in Trinidad de Las Minas, western Panama.

American cutaneous leishmaniasis (ACL) transmission patterns have been increasingly associated with domestic and peridomestic environments. Here, we present results from an epidemiological survey of 94 people from 24 households in Trinidad de Las Minas, western Panama. We studied the role of sand fly abundance, housing quality, peridomicile landscape matrix, and vegetation structure on shaping household clinical ACL rate patterns at Trinidad de Las Minas. We found that sand fly abundance was significantly associated with household clinical ACL rates, with a 6% rate increase for each additional Lutzomyia gomezi sand fly found inside a domicile.