Abstract
The increase in malaria transmission in the Amazon region motivated vector control units of the Ministry of Health of Ecuador and Peru to investigate Anopheles (Diptera: Culicidae) species present in transmission hotspots. Mosquitoes were collected using prokopack aspirators and CDC light traps (Ecuador) and human landing catch in Peru. In Ecuador, 84 Anopheles were captured from Pastaza, Morona Santiago, and Orellana provinces and identified morphologically [An. (An.) apicimacula Dyar and Knab, An. (Nys.) near benarrochi, An. (Nys.) near oswaldoi, An. (Nys.) near strodei, An. (An.) nimbus (Theobald, 1902), and An. (Nyssorhynchus) sp.]. In Peru, 1,150 Anopheles were collected in Andoas District. A subsample of 166 specimens was stored under silica and identified as An. near oswaldoi, An. darlingi, and An. (An.) mattogrossensis Lutz and Neiva. COI barcode region sequences were obtained for 137 adults (107 from Peru, 30 from Ecuador) identified by ITS2 PCR-RFLP as An. benarrochi Gabaldon, Cova Garcia, and Lopez and retained in the final analysis. Haplotypes from the present study plus An. benarrochi B GenBank sequences grouped separately from Brazilian An. benarrochi GenBank sequences by 44 mutation steps, indicating that the present study specimens were An. benarrochi B. Our findings confirm the presence of An. benarrochi B in Ecuador and reported here for the first time from the Amazonian provinces of Orellana and Morona Santiago. Furthermore, we confirm that the species collected in Andoas District in the Datem del Maranon Province, Peru, is An. benarrochi B, and we observed that it is highly anthropophilic. Overall, the known distribution of An. benarrochi B has been extended and includes southern Colombia, much of Peru and eastern Ecuador.
Morales D, Herrera M, Albuja M, Quiroga C. 2021. New Records of Anopheles benarrochi B (Diptera: Culicidae) in Malaria Hotspots in the Amazon Regions of Ecuador and Peru. Journal of Medical Entomology 58(Suppl 1).
Abstract
In Ecuador, the status of insecticide resistance for Aedes aegypti, the principal arboviral vector in the country, has not been previously evaluated. The aim of this research was to describe the resistance status of Ae. aegypti to the principal insecticides used for vector control in provinces with high reports of arboviral clinical cases. This was a descriptive study performed on Ae. aegypti collected from 2016 to 2017 in 14 localities of Ecuador. The larvae were reared and tested using bioassays applying the adulticides malathion and deltamethrin, and the larvicide temephos. The lethal concentrations were obtained for field-collected specimens and compared to the susceptible reference strain ROCK, MRA-734. Mosquitoes from all the localities showed resistance to deltamethrin and susceptibility to malathion. On the other hand, mosquitoes demonstrated resistance to the larvicide temephos in 5 of the 14 localities analyzed. The results obtained in this research may be used by healthcare decision-makers to improve vector control in Ecuador. Rotation of insecticides and alternative biological vector control strategies should be considered to manage the resistance observed in Ae. aegypti to deltamethrin and temephos. New strategies to use insecticides should also be aimed to prevent selective pressure with malathion.
Morales D, Ponce P, Cevallos V, Espinosa P, Vaca D, Quezada W. 2019. Resistance Status of Aedes aegypti to Deltamethrin, Malathion, and Temephos in Ecuador. Journal of the American Mosquito Control Association Volume 35, Issue 2.
Abstract
The increase in malaria transmission in the Amazon region motivated vector control units of the Ministry of Health of Ecuador and Peru to investigate Anopheles (Diptera: Culicidae) species present in transmission hotspots. Mosquitoes were collected using prokopack aspirators and CDC light traps (Ecuador) and human landing catch in Peru. In Ecuador, 84 Anopheles were captured from Pastaza, Morona Santiago, and Orellana provinces and identified morphologically [An. (An.) apicimacula Dyar and Knab, An. (Nys.) near benarrochi, An. (Nys.) near oswaldoi, An. (Nys.) near strodei, An. (An.) nimbus (Theobald, 1902), and An. (Nyssorhynchus) sp.]. In Peru, 1,150 Anopheles were collected in Andoas District. A subsample of 166 specimens was stored under silica and identified as An. near oswaldoi, An. darlingi, and An. (An.) mattogrossensis Lutz and Neiva. COI barcode region sequences were obtained for 137 adults (107 from Peru, 30 from Ecuador) identified by ITS2 PCR-RFLP as An. benarrochi Gabaldon, Cova Garcia, and Lopez and retained in the final analysis. Haplotypes from the present study plus An. benarrochi B GenBank sequences grouped separately from Brazilian An. benarrochi GenBank sequences by 44 mutation steps, indicating that the present study specimens were An. benarrochi B. Our findings confirm the presence of An. benarrochi B in Ecuador and reported here for the first time from the Amazonian provinces of Orellana and Morona Santiago. Furthermore, we confirm that the species collected in Andoas District in the Datem del Maranon Province, Peru, is An. benarrochi B, and we observed that it is highly anthropophilic. Overall, the known distribution of An. benarrochi B has been extended and includes southern Colombia, much of Peru and eastern Ecuador.
Morales D, Herrera M, Albuja M, Quiroga C. 2021. New Records of Anopheles benarrochi B (Diptera: Culicidae) in Malaria Hotspots in the Amazon Regions of Ecuador and Peru. Journal of Medical Entomology 58(Suppl 1).
Abstract
Introduction: Malaria is a vector-borne disease widely distributed in the Amazon region and the coastal area of northern Ecuador. Its epidemiology involves related factors such as human settlements, vector reproduction sites, mobility, productive activity, and the response capacity of health systems, among others.
Objective: To describe malaria transmission by Plasmodium vivax in a non-endemic area of Ecuador by analyzing the epidemiological and entomological factors involved.
Materials and methods: We conducted the epidemiological study of the cases reported in the Salinas canton and the characterization of vector breeding sites through captures of larvae and adult mosquitoes by human capture of resting mosquitoes.
Results: We detected 21 cases of malaria with local transmission related to the presence of initial cases in Venezuelan migrant patients and identified Anopheles albimanus as the predominant vector in natural breeding sites such as estuaries, wells, and water channels. Conclusions: We detected an outbreak of malaria triggered by imported cases from Venezuela. Climatic, social, environmental, and ecological conditions have favored the development of the vector maintaining the transmission cycle. Strategies to control imported malaria should be multiple including early case detection and control of productive breeding sites to avoid local transmission.
Objective: To describe malaria transmission by Plasmodium vivax in a non-endemic area of Ecuador by analyzing the epidemiological and entomological factors involved.
Materials and methods: We conducted the epidemiological study of the cases reported in the Salinas canton and the characterization of vector breeding sites through captures of larvae and adult mosquitoes by human capture of resting mosquitoes.
Results: We detected 21 cases of malaria with local transmission related to the presence of initial cases in Venezuelan migrant patients and identified Anopheles albimanus as the predominant vector in natural breeding sites such as estuaries, wells, and water channels. Conclusions: We detected an outbreak of malaria triggered by imported cases from Venezuela. Climatic, social, environmental, and ecological conditions have favored the development of the vector maintaining the transmission cycle. Strategies to control imported malaria should be multiple including early case detection and control of productive breeding sites to avoid local transmission.
Morales D, Quinatoa P, Cagua J. 2021. Characterization of an outbreak of malaria in a non-endemic zone on the coastal region of Ecuador. Biomédica. 2021;41(Supl.1):100-12.
Abstract
Chagas disease is a chronic and systemic parasitosis caused by the hemoflagellate protozoan Trypanosoma cruziand transmitted mainly by insects of the Triatominae subfamily. Currently, at least 151 species of Triatominae are recognized, with species of the genera, Triatoma, Rhodniusand Panstrongylus, with an important epidemiological role in the transmission of the disease. In Ecuador it is difficult to know the true epidemiological situation of this disease, its implications and the situation regarding its prevention and control management. A review of the epidemiological data of Chagas disease, published in theEpidemiological Surveillance Subsystem of the Ministry of Public Health from 2013 to 2019, was carried out. The systematic review of triatomine species was carried out based on original research published on the basis of public access data. The review carried out reported 439 confirmed cases of Chagas with a high incidence in the last two years. The prevalence has been slightly observed in women with a prevalent age group of 20 to 49 years. In Ecuador 17 species of triatomines are registered. The species Triatoma dimidiataand Rhodnius ecuadoriensisare the main vectors of the disease, with a high density in the provinces of Loja and Manabí due to their high capacity for adaptation and the colonization of new habitats. Chagas surveillance and control strategies should be carried out by linking epidemiological and vector aspects to stratify and strengthen control programs.
Morales D, Quinatoa P, Sánchez D, Cagua J, Veloz H. 2021. Chagas disease in Ecuador: a systematic review of epidemiological and entomological aspects. Revista INSPILIP.
Abstract
Cutaneous leishmaniasis (CL) is a neglected tropical disease transmitted by species of Phlebotominae sand flies. CL is responsible for more than 1000 reported cases per year in Ecuador. Vector collection studies in Ecuador suggest that there is a strong association between the ecological diversity of an ecosystem, the presence of potential alternative or reservoir hosts and the abundance of sand fly species. Data collected from a coastal community in Ecuador showed that Leishmania parasites may be circulating in diverse hosts, including mammalian and potentially avian species, and these hosts may serve as potential hosts for the parasite. There has been limited reporting of CL cases in Ecuador because the disease is non-fatal and its surveillance system is passive. Hence, the actual incidence of CL is unknown. In this study, an epidemic model was developed and analysed to understand the complexity of CL transmission dynamics with potential non-human hosts in the coastal ecosystem and to estimate critical epidemiological quantities for Ecuador. The model is fitted to the 2010 CL outbreak in the town of Valle Hermoso in the Santo Domingo de los Tsachilas province of Ecuador and parameters such as CL transmission rates in different types of hosts (primary and alternative), and levels of case reporting in the town are estimated. The results suggest that the current surveillance in this region fails to capture 38% (with 95% CI (29%, 47%)) of the actual number of cases under the assumption that alternative hosts are dead-end hosts and that the mean CL reproduction number in the town is 3.9. This means that on the average 3.9 new human CL cases were generated by a single infectious human in the town during the initial period of the 2010 outbreak. Moreover, major outbreaks of CL in Ecuador in coastal settings are unavoidable until reporting through the surveillance system is improved and alternative hosts are managed properly. The estimated infection transmission probabilities from alternative hosts to sand flies, and sand flies to alternative hosts are 27% and 32%, respectively. The analysis highlights that vector control and alternative host management are two effective programmes for Ecuador but need to be implemented concurrently to avoid future major outbreaks.
Morales D, Paredes M, Morales E, Cruz M, Arriola L, Cevallos V, Ponce P, Mubayi A. 2019. Data scarcity and ecological complexity: the cutaneous leishmaniasis dynamics in Ecuador. Journal of the Royal Society Interface.
Abstract
In Ecuador, the status of insecticide resistance for Aedes aegypti, the principal arboviral vector in the country, has not been previously evaluated. The aim of this research was to describe the resistance status of Ae. aegypti to the principal insecticides used for vector control in provinces with high reports of arboviral clinical cases. This was a descriptive study performed on Ae. aegypti collected from 2016 to 2017 in 14 localities of Ecuador. The larvae were reared and tested using bioassays applying the adulticides malathion and deltamethrin, and the larvicide temephos. The lethal concentrations were obtained for field-collected specimens and compared to the susceptible reference strain ROCK, MRA-734. Mosquitoes from all the localities showed resistance to deltamethrin and susceptibility to malathion. On the other hand, mosquitoes demonstrated resistance to the larvicide temephos in 5 of the 14 localities analyzed. The results obtained in this research may be used by healthcare decision-makers to improve vector control in Ecuador. Rotation of insecticides and alternative biological vector control strategies should be considered to manage the resistance observed in Ae. aegypti to deltamethrin and temephos. New strategies to use insecticides should also be aimed to prevent selective pressure with malathion.
Morales D, Ponce P, Cevallos V, Espinosa P, Vaca D, Quezada W. 2019.Resistance Status of Aedes aegypti to Deltamethrin, Malathion, and Temephos in Ecuador. Journal of the American Mosquito Control Association 35(2):113-122.
Abstract
Aedes (Stegomyia) albopictus (Skuse), (Diptera: Culicidae), the Asian tiger mosquito, is one of the most widespread invasive vector-borne disease insect in tropical and temperate zones. This species has invaded the Americas over the past 3 decades and has spread to six countries. We report Ae. albopictus in Guayaquil city, the first time it has been identified in Ecuador. Outdoor BG-Sentinel traps without lures collected a total of 21 Ae. albopictus.
Ponce P, Morales D, Argoti A, Cevallos V. 2018. First Report of Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae), the Asian Tiger Mosquito, in Ecuador. Journal on Medical Entomology 55(16): 248-249.
Abstract
The wide and rapid spread of Chikungunya (CHIKV) and Zika (ZIKV) viruses represent a global public health problem, especially for tropical and subtropical environments. The early detection of CHIKV and ZIKV in mosquitoes may help to understand the dynamics of the diseases in high-risk areas, and to design data based epidemiological surveillance to activate the preparedness and response of the public health system and vector control programs. This study was done to detect ZIKV and CHIKV viruses in naturally infected fed female Aedes aegypti (L.) mosquitoes from active epidemic urban areas in Ecuador. Pools (n = 193; 22 pools) and individuals (n = 22) of field collected Ae. aegypti mosquitoes from high-risk arboviruses infection sites in Ecuador were analyzed for the presence of CHIKV and ZIKV using RT-PCR. Phylogenetic analysis demonstrated that both ZIKV and CHIKV viruses circulating in Ecuador correspond to the Asian lineages. Minimum infection rate (MIR) of CHIKV for Esmeraldas city was 2.3% and the maximum likelihood estimation (MLE) was 3.3%. The minimum infection rate (MIR) of ZIKV for Portoviejo city was 5.3% and for Manta city was 2.1%. Maximum likelihood estimation (MLE) for Portoviejo city was 6.9% and 2.6% for Manta city. Detection of arboviruses and infection rates in the arthropod vectors may help to predict an outbreak and serve as a warning tool in surveillance programs.
Cevallos V, Ponce P, Waggoner J, Pinsky B, Coloma J, Quiroga C, Morales D, Cárdenas M.
2018. Zika and Chikungunya virus detection in naturally infected Aedes aegypti in Ecuador. Acta Tropica, pg. 74-80.
Abstract
The detection and identification of natural infections in sand flies by Leishmania protozoan species in endemic areas is a key factor in assessing the risk of leishmaniasis and in designing prevention and control measures for this infectious disease. In this study, we analyzed the Leishmania DNA using nuclear ribosomal internal transcript spacer (ITS) sequences. Parasite DNA was extracted from naturally infected, blood-fed sand flies collected in nine localities considered leishmaniasis-endemic foci in Ecuador.The species of parasites identified in sand flies were Leishmania major-like, Leishmania naiffi, Leishmania mexicana, Leishmania lainsoni, and “Leishmania sp. siamensis”. Sand fly specimens of Brumptomyia leopoldoi, Mycropigomyia cayennensis, Nyssomyia yuilli yuilli, Nyssomyia trapidoi, Pressatia triacantha, Pressatia dysponeta, Psychodopygus carrerai carrerai, Psychodopygus panamensis, and Trichophoromyia ubiquitalis were found positive for Leishmania parasite. These findings contribute to a better understanding of the epidemiology and transmission dynamics of the disease in high-risk areas of Ecuador.
Quiroga C, Cevallos V, Morales D, Baldeón M, Cardenas P, Rojas P, Ponce P. 2017.Molecular Identification of Leishmania spp. in Sand Flies (Diptera: Psychodidae, Phlebotominae) From Ecuador. Journal of Medical Entomology 54(6):1704-1711.
Abstract
Se evaluó la diversidad alfa de mosquitos y el riesgo a transmisión de patógenos con base en variables de rápida determinación. El muestreo se realizó en: zona urbana-rural, rural y rural-selvática de tres provincias. Veintidos especies fueron colectadas: 59 % son vectores comprobados; 45,5 % como adultos; 90,9 % en fases inmaduras; dos especies únicamente como adultos (9 %) y 12 especies únicamente como inmaduros (54,5 %). Cuatro especies fueron comunes a las tres provincias, 12 restringidas a una localidad y 9 en zona urbana. El 31,8 % mostraron antropofília. El 75 % de viviendas mantenian larvas de Culicidae, con índice aédico IC= 25 %, de recipientes IR= 5 %; Bretaeu= 37,5 %, con 8,56 recipientes/vivienda. Los resultados sugieren alta vulnerabilidad a la traslocación y propagación de patógenos. Para la evaluación deben considerarse cinco factores: presencia/abundancia relativa de vectores potenciales; porcentaje de antropofília; zona urbana: índices aédicos y socioeconómicos; presencia de especies selváticas y asociación a viviendas en zonas de transición y el muestreo debe contemplar técnicas de colecta para ambas fases de desarrollo -inmaduros y adultos- para evitar una subestimación de hasta un 50 % de la diversidad alfa con solo capturas para adultos.Palabras clave adicionales: Biodiversidad, ecoepidemiología, riesgo, salud ambiental, taxonomía.
Navarro JC, Arrivillag J, Morales D, Ponce P, Cevallos V. 2015. Evaluación rápida de biodiversidad de mosquitos (Diptera: Culicidae) y riesgo en salud ambiental en un área Montana del Chocó Ecuatoriano. Entomotropica 30(16): 160-173.
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