Species and population density of malaria vector Anopheles in Sichuan Province from 2011 to 2021 / 中国血吸虫病防治杂志

Objective To investigate the distribution of malaria vector Anopheles in Sichuan Province from 2011 to 2021, so as to provide the scientific evidence for improving the surveillance of malaria vector Anopheles and preventing re-establishment of imported malaria in Sichuan Province. Methods The density and species of Anopheles mosquitoes were investigated using human-bait trapping and light trapping techniques in malaria vector surveillance sites of Sichuan Province from 2011 to 2021. The number, population and density of captured Anopheles mosquitoes were collected and descriptively analyzed, and the geographical distribution map of malaria vectors was plotted using the software ArcGIS 10.7 in Sichuan Province. Results A total of 152 243 Anopheles mosquitoes were captured in malaria vector surveillance sites of Sichuan Province from 2011 to 2021, including 150 987 An. sinensis (99.18%) and 1 256 An. anthropophagus (0.82%), and no other Anopheles species were captured. The annual densities of An. sinensis and An. anthropophagus were 0.64 to 1.27 mosquitoes/(person-hour) and 0 to 0.07 mosquitoes/(person-hour) by the human-bait trapping technique, and 6.46 to 26.50 mosquitoes/(light-night) and 0 to 0.82 mosquitoes/(light-night) by the light trapping technique in malaria vector surveillance sites of Sichuan Province from 2011 to 2021. A relatively higher density of An. anthropophagus was seen in Renshou County, Jianyang City, Weiyuan County and Mabian Yi Autonomous County [> 0.40 mosquitoes/(person-hour)] by the human-bait trapping technique, and in Cuiping District and Gaoxian County in Yibin City [> 1.00 mosquito/(light-night)] by the light trapping technique in Sichuan Province from 2011 to 2018, with no An. anthropophagus captured from 2019 to 2021, and a relatively higher density of An. sinensis was detected in Emeishan City, Lushan County, Luojiang District, Tongchuan District and Zhaohua District [> 4.00 mosquitoes/(person-hour)] by the human-bait trapping technique, and in Huili County, Yuexi County, Dechang County, Langzhong City, Pingchang County and Xuanhan County [> 40.00 mosquitoes/(light-night)] by the light trapping technique in Sichuan Province from 2011 to 2021. Conclusions Malaria vectors were still widespread in Sichuan Province from 2011 to 2021, and An. sinensis was the dominant species of malaria vectors. There is still a risk of local re-establishment of imported malaria in Sichuan Province, and it is needed to continue to improve the surveillance of imported malaria cases and malaria vectors.

Dinámica de aparición de criaderos de Aedes aegypti (Diptera: Culicidae) en la provincia La Habana, 2013-2017 / Dynamics of the appearance of breeding sites of Aedes aegypti (Diptera: Culicidae) in the province of Havana, 2013-1017

Introducción: El Programa Nacional de Control de Aedes aegypti realiza actividades de rutina para controlar la trasmisión de arbovirosis en el país, pero siempre quedan poblaciones residuales del vector, que demandan de una vigilancia entomológica sostenible. Objetivo: Determinar la presencia de estadios inmaduros de Ae. aegypti en la provincia La Habana en el periodo 2013-2017. Métodos: Se realizó un análisis del número de criaderos larvales, detectados por los trabajadores del Programa Nacional de Control de Ae. aegypti, en La provincia La Habana entre 2013-2017. La frecuencia de los muestreos fue mensual y se siguió la metodología de encuestas del programa. Resultados: Al analizar el número de criaderos larvales por meses de los 15 municipios de provincia La Habana, se observó un incremento de estos en el periodo de junio a octubre en todos los años y un pico entre los meses de enero a marzo en los años 2014, 2016 y 2017. La incidencia de Ae. aegypti resultó homogénea al comparar las medias por año, excepto para el año 2015 en el cual se observó una disminución significativa en el número de criaderos en comparación solo con el año 2017. Conclusiones: A pesar del esfuerzo que realizan los trabajadores del programa, no se ha logrado una disminución significativa de criaderos de Ae. aegypti, lo que evidencia la necesidad de fortalecer los sistemas de vigilancia y mantener la sostenibilidad de las acciones para controlar de forma efectiva la trasmisión de arbovirosis en la provincia La Habana(AU)

Introduction: The National Aedes aegypti Control Program carries out routine activities to control the transmission of arbovirus infections in the country. However, there still exist residual populations of the vector which require sustainable entomological surveillance. Objective: Determine the presence of immature stage Ae. aegypti in the province of Havana in the period 2013-2017. Methods: An analysis was conducted of the number of larval breeding sites detected by workers from the National Ae. aegypti Control Program in the province of Havana in the period 2013-2017. Sampling was performed on a monthly basis following the surveying methodology of the Program. Results: Analysis of the data on larval breeding sites per month in the 15 municipalities of the province of Havana revealed an increase in their number in the June-October period of every year, and a peak between the months of January and March in the years 2014, 2016 and 2017. Comparison of mean values per year found that incidence of Ae. aegypti was homogeneous, except for the year 2015, when a significant decrease was observed in the number of breeding sites only with respect to the year 2017. Conclusions: Despite the effort made by workers from the Program, a significant reduction has not been achieved in the number of Ae. aegypti breeding sites, which is evidence of the need to strengthen the surveillance systems and maintain the sustainability of the actions performed to effectively control the transmission of arbovirus infections in the Havana province(AU)

Should we bother doing dengue vector surveillance, and if so, how should we do it?

@#There is an enduring disconnect between the routine surveillance of mosquitoes that transmit dengue viruses and control activities to limit disease spread. A great variety of methods used to collect vector surveillance data exists globally, with program design typically influenced by historical, socio-cultural and cost factors. Surveillance data can be expensive to collect, meaning that without demonstration of its usefulness in directing mosquito control it may be deprioritized or even abandoned. Given that universally prescribed surveillance methods are unlikely to be sustainable and successful, we propose that strategies be designed according to the local terroir of dengue transmission. Strategy design should consider not only costs, but the amenability of workers and the public to various methods, the utility of methods for directing control and reducing disease, and the underlying spatial structure of the vector populations locally. A process of evaluating each of these factors should precede strategy design and be part of on-going review processes. In the case that the usefulness of vector surveillance cannot be demonstrated, then it may be argued that resources could be allocated to other aspects of disease control.

Vector surveillance in Jiangsu Province during the stage of malaria elimination / 中国血吸虫病防治杂志

To analyze the vector surveillance results during the stage of malaria elimination, so as to provide the evidence for assessing the local transmission risk of imported malaria and carrying out the surveillance work after malaria elimination in Jiangsu Province.From 2011 to 2017, the mosquito population was monitored and human biting rates were calculated by the half overnight human baiting trapping method and overnight lamp trapping method in 7 surveillance sites from June to October. The insecticide resistance level was tested by the force contact method recommended by WHO.A total of 5 106 Anopheles mosquitoes were captured by the half over-night human baiting trapping method in the 7 sites from 2011 to 2017, and all the mosquitoes were identified as Anopheles sinensis. The annual human biting rates were 1.075, 0.786, 1.057, 0.787, 0.790, 1.797 and 1.185 mosquitoes/ (human·hour), respectively. Totally 28 186 Anopheles mosquitoes were caught by the overnight lamp trapping method, and all the mosquitoes were An. sinensis. The densities of Anopheles mosquitoes were 57.950, 50.932, 14.800, 4.405, 58.070, 72.406, and 17.145 mosquitoes/ (night·lamp), respectively. In 2012, the resistance indexes of An. sinensis to deltamethrin, DDT and malathion were at R level in Jiangsu Province.The major vector is An. sinensis and no An. anthropophagus is found in Jiangsu Province. An. sinensis has a high level of resistance to deltamethrin, DDT and malathion.

Una propuesta para evaluar la calidad del trabajo en el control del Aedes aegypti / Proposal of evaluation of the work quality in the Aedes aegypti control

Evaluar los procesos de trabajo para el control del Aedes Aegypti constituye una necesidad, y lo es mucho más, disponer de metodologías que permitan valorar integradamente las actividades que realizan las unidades organizativas que tienen ese encargo. Nos propone mos exponer los aspectos principales que fundamentaron la concepción y diseño de una propuesta metodológica para evaluar el desempeño de los departamentos de Vigilancia y Lucha Antivectorial, desde los procesos que realizan en el control del Aedes aegypti. La propuesta metodológica se deriva de una investigación de desarrollo en que la revisión bibliográfica y documental, testimonios de informantes clave, observación directa, ejecución de investigaciones operacionales, entre otros procedimientos, sustentaron un proceso concebido en la articulación coherente y racional de pasos imprescindibles para dar respuesta a un grupo de interrogantes respecto al objeto de estudio y al diseño de la Propuesta. Se estructura en seis etapas, conforme a la finalidad de los procederes a ejecutar en su aplicación y en cada una de ellas se proporcionan los elementos metodológicos a considerar para la evaluación. La evaluación con esta propuesta metodológica constituye un proceso dinámico que enfatiza en las relaciones de coordinación a nivel del área de salud. Los resultados documentan sobre problemas técnicos y organizacionales en el cumplimiento de los procesos de trabajo, con énfasis en las debilidades existentes en la interacción sistemática y permanente de los Departamentos de Vigilancia con otras unidades organizativas. La propuesta constituye un aporte directo a la práctica de los servicios de Higiene y Epidemiología en el nivel primario de atención, también contribuye a la toma de decisiones certeras y al mejoramiento continuo de la calidad en sus unidades organizativas(AU)

The evaluation of the work processes for Aedes Aegypti control is a requirement, and it is even more necessary to have methodologies that allow comprehensively assessing the activities of the organizational units in charge of this task. This paper was intended to present the main aspects that substantiated the conception and design of a methodological proposal to evaluate the performance of the anti-vector surveillance and control, starting from the processes in the Aedes Aegypti control. The methodological proposal was derived from a development research in which the literature and documentary reviews, testimonies of key informants, direct observation, implementation of operational research works, among other procedures, supported a process conceived in the coherent and rational articulation of indispensable steps to answer a group of questions in relation to the object of study and the design of the proposal. It is structured into six phases pursuant to the aim of the procedures to be implemented in their application and in each of them, the methodological elements for evaluation were provided. Based on this methodological proposal, the evaluation represents a dynamic process emphasizing the coordinating relationships at the health area level. The results documented about the technical and organizational problems encountered in the fulfillment of the work processes, with emphasis on the existing weaknesses in the permanent systematic interaction of the surveillance department with other organizational units. This proposal is a direct contribution to the practice of hygiene and epidemiology services at the primary health care and also helps in right decision-taking and continuous improvement of quality in the organizational units(AU)

Need for an efficient adult trap for the surveillance of dengue vectors.

The emergence and re-emergence of arboviral diseases transmitted by Aedes aegypti and Ae. albopictus continue to be a major threat in the tropics and subtropics. Associations between currently used indices and dengue transmission have not been proven to be satisfactorily predictive of dengue epidemics. Classical larval indices in dengue surveillance have limited use in assessing transmission risk and are a poor proxy for measuring adult emergence. Besides, collection of larval indices is labour intensive and plagued by difficulties of access particularly in urban settings. The re-emergence of dengue disease in many countries despite lower immature indices has warranted the need for more effective indices in dengue vector surveillance and control. Reliable and highly useful indices could be developed with the help of efficient and appropriate entomological tools. Most current programmes emphasize reduction of immature Ae. aegypti density, but it is of little value because its relation to transmission risk is weak. More attention should be paid to methods directed toward adult rather than immature Ae. aegypti. Collection of sufficient numbers of adult mosquitoes is important to understand disease transmission dynamics and to devise an appropriate control strategy. Even though, use of certain traps such as BG-Sentinel traps has been attempted in monitoring Ae. aegypti population, their utility is limited due to various setbacks which make these insufficient for entomological and epidemiological studies. Thus, there is an urgent need for the development of an ideal trap that could be used for adult vector surveillance. The present review critically analyzes the setbacks in the existing tools of entomological surveillance of dengue vectors and highlights the importance and necessity of more improved, more sensitive and reliable adult trap that could be used for surveillance of dengue vectors.

Synanthropic triatomines (Hemiptera, Reduviidae) in the state of Pernambuco, Brazil: geographical distribution and natural Trypanosoma infection rates between 2006 and 2007 / Triatomíneos sinantrópicos (Hemiptera, Reduviidae) no estado de Pernambuco, Brasil: distribuição geográfica e índices de infecção natural por Trypanosoma entre 2006 e 2007

INTRODUCTION: The present study shows a descriptive analysis of triatomine occurrence and its natural Trypanosoma infection rates in the state of Pernambuco, Brazil, between 2006 and 2007. METHODS: Entomological data for the species, such as specimens captured in both intra and peridomiciles and natural infection index, were obtained via domiciliary capture in 147 municipalities from 11 Regional Managements of Health. The database was obtained from a sample of insects (100 percent infected and 20 percent non-infected) sent to the Central Laboratory of Pernambuco. RESULTS: A total of 18,029 triatomines were analyzed from 138 municipalities of the state. Triatoma pseudomaculata (35 percent), Triatoma brasiliensis (34 percent), and Panstrongylus lutzi (25 percent) were the most captured species. These species also showed a widespread geographical distribution in the state. Panstrongylus megistus, Triatoma petrocchiae, Triatoma melanocephala, Triatoma sordida, Rhodnius nasutus, Rhodnius neglectus, and Triatoma infestans showed more limited geographical distribution and lower relative abundance. The parasitological research showed that 8.8 percent of the triatomines were naturally infected with flagellates morphologically similar to Trypanosoma cruzi and 91.3 percent of them were captured inside houses in 113 municipalities. P. lutzi showed the highest rates of natural infection. CONCLUSIONS: After the control of T. infestans, synanthropic species, such as T. brasiliensis, T. pseudomaculata, and P. lutzi, maintain the risk of T. cruzi transmission to humans in the state of Pernambuco. These species are widely distributed, and infected specimens have been found inside houses. Thus, an enhanced surveillance and vector control of Chagas disease is recommended in Pernambuco.

INTRODUÇÃO: O presente estudo apresenta uma análise descritiva da ocorrência de triatomíneos e seus índices de infecção natural por Trypanosoma no Estado de Pernambuco, entre 2006 e 2007. MÉTODOS: Dados entomológicos para as espécies de triatomíneos, tais como espécimes capturados no intra e peridomicílio, e índice de infecção natural foram obtidos por meio da captura domiciliar em 147 municípios das 11 Gerências Regionais de Saúde. A pequisa foi baseada em uma amostra de insetos (100 por cento dos infectados e 20 por cento dos não infectados) enviados para o Laboratório Central de Pernambuco. RESULTADOS: No total, 18.029 triatomíneos foram analisados provenientes de 138 municípios. Triatoma pseudomaculata (35 por cento), Triatoma brasiliensis (34 por cento) e Panstrongylus lutzi (25 por cento) foram as espécies mais capturadas. Estas espécies também apresentaram ampla distribuição geográfica no estado. Panstrongylus megistus, Triatoma petrocchiae, Triatoma melanocephala, Triatoma sordida, Rhodnius nasutus, Rhodnius neglectus e Triatoma infestans apresentaram distribuição geográfica mais restrita e menores valores de abundância relativa. A pesquisa parasitológica mostrou que 8,8 por cento dos triatomíneos estavam infectados por flagelados morfologicamente similares a Trypanosoma cruzi e 91,3 por cento deles foram capturados no interior das habitações em 113 municípios. P. lutzi apresentou as maiores taxas de infecção natural. CONCLUSÕES: Após o controle do T. infestans, as espécies sinantrópicas T. brasiliensis, T. pseudomaculata e P. lutzi mantêm o risco de transmissão do T. cruzi ao homem no Estado de Pernambuco. Estas espécies são amplamente distribuídas e espécimes infectados foram encontrados dentro das casas. Assim, nossos resultados recomendam reforçar a vigilância e controle vetorial da doença de Chagas em Pernambuco.

Letter to the Editor: Dengue vector surveillance methods in Muntinlupa City, Philippines

This work is part of a larger study that aims to build a low-cost, geographically-enhanced dengue data management system for use by local health authorities. The system will collate data from a range of sources and produce regular reports and maps showing cases, vectors and predicted dengue clusters. Local health authorities can use these outputs to better target dengue control activities, including community education, removal of breeding sites, preventive fogging and improved waste and water management.

Mosquito traps designed to capture Aedes aegypti (Diptera: Culicidae) females: preliminary comparison of Adultrap, MosquiTRAP and backpack aspirator efficiency in a dengue-endemic area of Brazil

In this report, the efficiency of Adultrap under field conditions is compared to a CDC backpack aspirator and to MosquiTRAP. An urban dengue-endemic area of Rio de Janeiro was selected to evaluate the efficiency of mosquito traps in capturing Aedes aegypti females. Adultrap and aspirator captured similar numbers of Ae. aegypti females, with the former showing high specificity to gravid individuals (93.6 percent). A subsequent mark-release-recapture experiment was conducted to evaluate Adultrap and MosquiTRAP efficiency concomitantly. With a 6.34 percent recapture rate, MosquiTRAP captured a higher mean number of female Ae. aegypti per trap than Adultrap (Ç2 = 14.26; df = 1; p < 0,05). However, some MosquiTRAPs (28.12 percent) contained immature Ae. aegypti after 18 days of exposure in the field and could be pointed as an oviposition site for female mosquitoes. Both trapping methods, designed to collect gravid Ae. aegypti females, seem to be efficient, reliable and may aid routine Ae. aegypti surveillance.

Medidas dos níveis de infestaçäo urbana para Aedes (Stegomyia) aegypti e Aedes (Stegomyia) albopictus em programa de vigilância entomológica / Measurement of the urban infestation level for Aedes aegypti and Aedes albopictus in the programme of entomological surveillance

Revisa os métodos e índices empregados para Aedes aegypti e Aedes albopictus em programa de vigilância entomológica. Aborda a medida do nível de infestação urbana e os fatores de risco de transmissão da dengue e febre amarela. Descreve os índices de acordo com os estágios imaturos e adulto do vetor e respectivo significado epidemiológico. Faz uma análise crítica dos índices para facilitar a compreensão da densidade do vetor como fator de risco. Além disso, as vantagens e desvantagens dos índices ajudarão escolher o mais apropriado índice para medir o nível de infestação em cada município

The methods and indices used for Aedes aegypti and Aedes albopictus in the programme of entomological surveillance are reviewed. The measurement of the urban infestation level and the risk factors for dengue and yellow fever transmission are discussed. The indices for the immature and adult stages of the vector and their respective epidemiological significance are described. A critical analysis has been made to facilitate the understanding of vector density as a risk factor The advantages and disadvantages of the indices will help in the choice of the most appropriate one to measure the infestation level in each county

Malaria Situation and Evaluation on the Control Effect in Henan Province during 1990-2005 / 中国寄生虫学与寄生虫病杂志

Objective To analyze malaria situation and evaluate the effect of control program in Henan Province during 1990-2005. Methods Data were collected and analyzed on the measures and effects of malaria control, vector surveillance, blood examination for cases with fever and serological surveillance in the province during 1990-2005. Results In the 16 years, a total of 802 700 people were given pre-transmission season treatment with chloroquine and primaquine for a radical cure of vivax malaria, chemoprophylaxis was given to 764 300 people at high risk during the transmission season, treatment or presumptive treatment was given to 43 891 cases. 11 216 100 cases with fever were tested and 11 213 (0.10%) were found positive accounting for 29.01% (11 213/338 654) of all malaria cases. A total of 1 332 800 bed nets were treated with insecticide and 1 999 300 people were protected in 1990-1992 and 1996-1999. 34 846 residents including pupils were tested with IFAT in 1990-2000 and 1149 (3.30%) were positive. The parasite rate amongst 71 234 local residents including pupils was 0.40% (286/71 234). The principal transmitting vectors were Anopheles sinensis and An.anthropophagus. The man-biting habit for An. sinensis and An.anthropophagus was 0.060 8 and 0.314 3 respectively, and the vectorial capacity of An.anthropophagus was 22.4 times higher than that of An.sinensis. In this period, 38 654 malaria cases were reported in the province and the annual malaria incidence was 2.62 per hundred thousand, the lowest annual incidence was in 1992 (0.37 per hundred thousand). 70.05% (27 076/38 654) of these malaria cases were from areas where An. anthropophagus was present. Conclusions In general, the malaria control activities have been effective and the epidemiological situation kept stable in Henan Province, although in some areas the situation is unstable and outbreak spots or focal epidemics occur.