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Host-biting rate and susceptibility of some suspected vectors to Leishmania braziliensis

Diniz, Morgana Michele Cavalcanti de Souza Leal; Ovallos, Fredy Galvis; Gomes, Claudia Maria de Castro; Lavitschka, Cecilia de Oliveira; Galati, Eunice Aparecida Bianchi
Fonte: BMC Publicador: BMC
Tipo: Artigo de Revista Científica
EN
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Abstract Background American tegumentary leishmaniasis is a serious Brazilian public health problem. This diseases is attributed to seven species of Leishmania, however, the majority of cases are associated with Leishmania braziliensis. Some phlebotomine species have been implicated in the transmission of this parasite, nonetheless only Psychodopygus wellcomei has had its vectorial competence demonstrated. Thus this study sought to assess some parameters related to the vectorial capacity of anthropophilic species of sand fly occurring in São Paulo state: Pintomyia fischeri, Migonemyia migonei Nyssomyia intermedia, Nyssomyia whitmani, Expapillata firmatoi and Psychodopygus ayrozai, under laboratory conditions. These parameters were the duration of the gonotrophic cycle, proportion of females which feed on hamster, the rate of infection by L. braziliensis and the duration of the extrinsic incubation period. Methods The sandflies were collected in three regions of the São Paulo state: Greater São Paulo and the Mogi Guaçu and Iporanga municipalities. To assess the proportion of engorged females the insects were fed on hamsters to estimate the duration of the gonotrophic cycle. To estimate the susceptibility to infection of each species...

Estudo da capacidade vetorial de Migonemya migonei (França) e de Pintomya fischeri (Pinto) (Diptera: Psychodidae) para Leishmania (Leishmania) infantum chagasi Cunha & Chagas; Study of the vectorial capacity of Migonemyia migonei (França) and of Pintomyia fischeri (Pinto) (Diptera: Psychodidae) as regards Leishmania (Leishmania) infantum chagasi Cunha & Chagas

Ovallos, Fredy Galvis
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/11/2011 PT
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Introdução - A leishmaniose visceral no Estado de São Paulo vem acometendo populações caninas e humanas de vários centros urbanos e encontra-se em franca expansão. Desde a sua introdução no Estado de São Paulo, novas áreas na região metropolitana da Grande São Paulo têm sido identificadas com a infecção na população canina e felina, sem que a espécie vetora comprovada, Lutzomyia longipalpis, tenha sido encontrada. Diferentemente de outras áreas, onde a transmissão da leishmaniose visceral se dá em ambiente urbano consolidado, na Grande São Paulo, ocorre em ambiente de transição urbano-rural. Neste ocorrem resíduos de matas nos quais os flebotomíneos antropofílicos, Pintomyia fischeri e Migonemyia migonei se desenvolvem. A capacidade vetorial é definida como a taxa diária de picadas potencialmente infectivas que a população de um vetor levará a cabo ao se alimentar em um único tipo de hospedeiro (REISEN, 1989). Objetivo Comparar a capacidade vetorial de Pintomyia fischeri e Migonemyia migonei oriundas de foco de leishmaniose visceral canina da Grande São Paulo e compará-la com a de Lu. longipalpis, proveniente de área endêmica, Campo Grande, estado de Mato Grosso do Sul, para a transmissão do agente...

Capacidade vetorial de Lutzomyia (Lutzomyia) cruzi (Diptera: Psychodidae) para Leishmania (Leishmania) infantum; Vectorial capacity of Lutzomyia (Lutzomyia) cruzi (Diptera: Psychodidae) for Leishmania (Leishmania) infantum.

Oliveira, Everton Falcão de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 31/03/2015 PT
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66.67%
Em algumas regiões, como nos municípios de Corumbá e Ladário, no Estado de Mato Grosso do Sul, existem evidências ecológicas e epidemiológicas de que Lutzomyia (Lutzomyia) cruzi (Mangabeira, 1938) seja a principal responsável pela transmissão do protozoário Leishmania (Leishmania) infantum Nicolle, 1908 (ou subespécie de L. (L.) infantum chagasi Cunha & Chagas, 1937 segundo alguns autores), agente etiológico da leishmaniose visceral (LV). A ausência de Lutzomyia (Lutzomyia) longipalpis (Lutz & Neiva, 1912), principal vetor do parasito, reforçam esta hipótese. Este estudo teve por objetivo avaliar os parâmetros e estimar a capacidade vetorial de Lu. cruzi para L. (L.) infantum e Leishmania (Leishmania) amazonensis Lainson & Shaw, 1972. Para este último, apenas foram avaliados os parâmetros, sem a estimativa numérica da capacidade vetorial. A avaliação da capacidade vetorial foi realizada a partir de experimentos laboratoriais (infecção experimental) e de campo (atratividade aos flebotomíneos). Por intermédio da infecção experimental de Lu. cruzi pelo parasito, foi possível estimar a expectativa de sobrevida diária de fêmeas infectadas (estimativa vertical e laboratorial), avaliar o período de incubação extrínseco do parasita e obter duração do ciclo gonotrófico. Para a avaliação da competência vetorial do inseto...

Seasonality effects on Dengue

Rodrigues, Helena Sofia; Monteiro, M. Teresa T.; Torres, Delfim F. M.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 ENG
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Dengue is a vector-borne disease transmitted from an infected human to an Aedes mosquito, during a blood-meal. A model for dengue disease transmission is presented, composed by human and mosquitoes compartments. The aim of this work is to simulate the effects of seasonality, on the vectorial capacity. Using entomological information about the mosquito behavior under different temperatures, simulations were carried out and the repercussions on the disease transmission were analyzed.; This work was supported by Portuguese funds through The Portuguese Foundation for Science and Technology (FCT). Rodrigues and Torres were also supported by the Center for Research and Development in Mathematics and Applications (CIDMA) within project PEst-OE/MAT/UI4106/2014; Monteiro by the ALGORITMI Research Centre and project PEST-OE/EEI/UI0319/2014.

Triatoma rubrovaria (Blanchard, 1843) (Hemiptera - Reduviidae - Triatominae) IV: bionomic aspects on the vector capacity of nymphs

Almeida,Carlos Eduardo; Folly-Ramos,Elaine; Agapito-Souza,Ronildo; Magno-Esperança,Gleidson; Pacheco,Raquel S; Costa,Jane
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2005 EN
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46.25%
Triatoma rubrovaria has become the most frequently captured triatomine species since the control of T. infestans in the state of Rio Grande do Sul (RS), Brazil. The aim of this study was to evaluate aspects of the vectorial competence of T. rubrovaria using nymphs raised in laboratory under environmental conditions of temperature and humidity and fed on mice. The average developmental period of T. rubrovaria was 180.1 days. The percentage of defecation shortly after feeding was still higher than previous studies in which samples of T. rubrovaria subjected to a slight starvation period before the blood meal were used. The obtained results support former indication that T. rubrovaria presents bionomic characteristics propitious to be a good vector of Trypanosoma cruzi to man. Therefore its domiciliary invasion process must be continuously monitored.

Distribution of sibling species of Anopheles culicifacies s.l. and Anopheles fluviatilis s.l. and their vectorial capacity in eight different malaria endemic districts of Orissa, India

Tripathy,Asima; Samanta,Luna; Das,Sachidananda; Parida,Sarat Kumar; Marai,Nitisheel; Hazra,Rupenansu Kumar; Kar,Santanu Kumar; Mahapatra,Namita
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
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66.43%
The study was undertaken in eight endemic districts of Orissa, India, to find the members of the species complexes of Anopheles culicifacies and Anopheles fluviatilis and their distribution patterns. The study area included six forested districts (Keonjhar, Angul, Dhenkanal, Ganjam, Nayagarh and Khurda) and two non-forested coastal districts (Puri and Jagatsingpur) studied over a period of two years (June 2007-May 2009). An. culicifacies A, B, C and D and An. fluviatilis S and T sibling species were reported. The prevalence of An. culicifacies A ranged from 4.2-8.41%, B from 54.96-76.92%, C from 23.08-33.62% and D from 1.85-5.94% (D was reported for the first time in Orissa, except for occurrences in the Khurda and Nayagarh districts). The anthropophilic indices (AI) were 3.2-4.8%, 0.5-1.7%, 0.7-1.37% and 0.91-1.35% for A, B, C and D, respectively, whereas the sporozoite rates (SR) were 0.49-0.54%, 0%, 0.28-0.37% and 0.41-0.46% for A, B, C and D, respectively. An. fluviatilis showed a similarly varied distribution pattern in which S was predominant (84.3% overall); its AI and SR values ranged from 60.7-90.4% and 1.2-2.32%, respectively. The study observed that the co-existence of potential vector sibling species of An. culicifacies (A...

Vectorial capacity of Triatoma guasayana (Wygodzinsky & Abalos) (Hemiptera: Reduviidae) compared with two other species of epidemic importance

Loza-Murguía,Manuel; Noireau,François
Fonte: Sociedade Entomológica do Brasil Publicador: Sociedade Entomológica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 EN
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Triatoma guasayana (Wygodzinsky & Abalos) is a peridomestic triatomine with epidemiological importance in Bolivia, that may play an important role in the transmission of Trypanosoma cruzi (Chagas). In this study, two parameters of vectorial capacity were evaluated: the interval of feeding-defecation time and metacyclogenesis, in adult males and females and nymphal instars II to V of T. guasayana with comparisons with Triatoma infestans (Klug) and T. sordida (Stal). The results showed a close relationship between ingestion of blood and beginning of defecation. Values were negative in T. infestans, and T. sordida for instars II, III, IV, and V and also males and females but were positive in female T. sordida. Triatoma guasayana showed only negative values for instar II. Adults and nymphs began defecation as soon as they had finished feeding and required an average of 29.8 min. The analysis of metacyclogenesis showed that T. guasayana was superior to T. infestans and T. sordida. However, the vectorial effectiveness of T. guasayana was significantly affected regarding the percentage of metacyclic trypomastigotes during instars III to V and showed a progressive increase. Females had higher proportions despite their ingestion being half that of T. infestans. The different instars of T. guasayana had a higher parasitic load than those of T. sordida and...

Natural vertical transmission by Stegomyia albopicta as dengue vector in Brazil

Cecílio,AB.; Campanelli,ES.; Souza,KPR.; Figueiredo,LB.; Resende,MC.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2009 EN
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The mosquito Stegomyia albopicta is among the most important arbovirus vectors in the world, particularly for Dengue viruses. Their natural history suggests that biologically these viruses are highly adapted to their mosquito hosts and they were most likely mosquito viruses prior to becoming adapted to lower primates and humans. As well as being maintained by transmission among susceptible humans, Dengue viruses may also be maintained by vertical transmission in mosquitoes during inter-epidemic periods. The larvae and mosquitoes of Stegomyia albopicta were used to identify the vertical transmission of the dengue virus in nature and to confirm the vectorial capacity concerning the Dengue virus type 2 infection. The minimum infection rate concerning S. albopicta infection with the Dengue virus was 1:36.45. In Brazil this was the first time that high minimum infection rates of vertical transmission of S. albopicta were detected in this species.

AEDES AEGYPTI VECTORIAL CAPACITY IS DETERMINED BY THE INFECTING GENOTYPE OF DENGUE VIRUS

ANDERSON, JUSTIN R.; RICO-HESSE, REBECA
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/2006 EN
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Dengue viruses causing severe, hemorrhagic disease have displaced less virulent strains in the Americas during the past three decades. The American (AM) genotype of dengue serotype 2 has been endemic in the Western Hemisphere and South Pacific, causing outbreaks of dengue fever (DF), but has not been linked to dengue hemorrhagic fever (DHF). The Southeast Asian (SEA) genotype of dengue was introduced into this hemisphere in 1981, has caused outbreaks with numerous cases of DHF, and has displaced the AM genotype in several countries. We investigated the effect of viral genotype on the potential for transmission by infecting Aedes aegypti mosquitoes collected in South Texas with six viruses, representing these two genotypes. Viral replication in the midgut was significantly higher in SEA-infected mosquitoes, and virus-specific proteins could be detected in salivary glands 7 days earlier in SEA- than AM-infected mosquitoes. This much earlier appearance of dengue virus in salivary glands resulted in an estimated 2- to 65-fold increase in the vectorial capacity of these mosquitoes for the viruses that can cause DHF. This may be one of the mechanisms through which more virulent flaviviruses spread and displace others globally.

A Vectorial Capacity Product to Monitor Changing Malaria Transmission Potential in Epidemic Regions of Africa

Ceccato, Pietro; Vancutsem, Christelle; Klaver, Robert; Rowland, James; Connor, Stephen J.
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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46.43%
Rainfall and temperature are two of the major factors triggering malaria epidemics in warm semi-arid (desert-fringe) and high altitude (highland-fringe) epidemic risk areas. The ability of the mosquitoes to transmit Plasmodium spp. is dependent upon a series of biological features generally referred to as vectorial capacity. In this study, the vectorial capacity model (VCAP) was expanded to include the influence of rainfall and temperature variables on malaria transmission potential. Data from two remote sensing products were used to monitor rainfall and temperature and were integrated into the VCAP model. The expanded model was tested in Eritrea and Madagascar to check the viability of the approach. The analysis of VCAP in relation to rainfall, temperature and malaria incidence data in these regions shows that the expanded VCAP correctly tracks the risk of malaria both in regions where rainfall is the limiting factor and in regions where temperature is the limiting factor. The VCAP maps are currently offered as an experimental resource for testing within Malaria Early Warning applications in epidemic prone regions of sub-Saharan Africa. User feedback is currently being collected in preparation for further evaluation and refinement of the VCAP model.

Effects of Plant-Community Composition on the Vectorial Capacity and Fitness of the Malaria Mosquito Anopheles gambiae

Stone, Christopher M.; Jackson, Bryan T.; Foster, Woodbridge A.
Fonte: The American Society of Tropical Medicine and Hygiene Publicador: The American Society of Tropical Medicine and Hygiene
Tipo: Artigo de Revista Científica
Publicado em 03/10/2012 EN
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Dynamics of Anopheles gambiae abundance and malaria transmission potential rely strongly on environmental conditions. Female and male An. gambiae use sugar and are affected by its absence, but how the presence or absence of nectariferous plants affects An. gambiae abundance and vectorial capacity has not been studied. We report on four replicates of a cohort study performed in mesocosms with sugar-poor and sugar-rich plants, in which we measured mosquito survival, biting rates, and fecundity. Survivorship was greater with access to sugar-rich plant species, and mortality patterns were age-dependent. Sugar-poor populations experienced Weibull mortality patterns, and of four populations in the sugar-rich environment, two female and three male subpopulations were better fitted by Gompertz functions. A tendency toward higher biting rates in sugar-poor mesocosms, particularly for young females, was found. Therefore, vectorial capacity was pulled in opposing directions by nectar availability, resulting in highly variable vectorial capacity values.

Evolution of sexual traits influencing vectorial capacity in anopheline mosquitoes

Mitchell, Sara N.; Kakani, Evdoxia G.; South, Adam; Howell, Paul I.; Waterhouse, Robert M.; Catteruccia, Flaminia
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 27/02/2015 EN
Relevância na Pesquisa
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The availability of genome sequences from 16 anopheline species provides unprecedented opportunities to study the evolution of reproductive traits relevant for malaria transmission. In Anopheles gambiae, a likely candidate for sexual selection is male 20-hydroxyecdysone (20E). Sexual transfer of this steroid hormone as part of a mating plug dramatically changes female physiological processes intimately tied to vectorial capacity. By combining phenotypic studies with ancestral state reconstructions and phylogenetic analyses, we show that mating plug transfer and male 20E synthesis are both derived characters that have coevolved in anophelines, driving the adaptation of a female 20E-interacting protein that promotes oogenesis via mechanisms also favoring Plasmodium survival. Our data reveal coevolutionary dynamics of reproductive traits between the sexes likely to have shaped the ability of anophelines to transmit malaria.

Effect of Larval Competition on Extrinsic Incubation Period and Vectorial Capacity of Aedes albopictus for Dengue Virus

Bara, Jeffrey; Rapti, Zoi; Cáceres, Carla E.; Muturi, Ephantus J.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 07/05/2015 EN
Relevância na Pesquisa
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Despite the growing awareness that larval competition can influence adult mosquito life history traits including susceptibility to pathogens, the net effect of larval competition on human risk of exposure to mosquito-borne pathogens remains poorly understood. We examined how intraspecific larval competition affects dengue-2 virus (DENV-2) extrinsic incubation period and vectorial capacity of its natural vector Aedes albopictus. Adult Ae. albopictus from low and high-larval density conditions were orally challenged with DENV-2 and then assayed for virus infection and dissemination rates following a 6, 9, or 12-day incubation period using real-time quantitative reverse transcription PCR. We then modeled the effect of larval competition on vectorial capacity using parameter estimates obtained from peer-reviewed field and laboratory studies. Larval competition resulted in significantly longer development times, lower emergence rates, and smaller adults, but did not significantly affect the extrinsic incubation period of DENV-2 in Ae. albopictus. Our vectorial capacity models suggest that the effect of larval competition on adult mosquito longevity likely has a greater influence on vectorial capacity relative to any competition-induced changes in vector competence. Furthermore...

Vectorial capacity, basic reproduction number, force of infection and all that: formal notation to complete and adjust their classical concepts and equations

Massad, Eduardo; Bezerra Coutinho, Francisco Antonio
Fonte: FUNDACO OSWALDO CRUZ; RIO DE JANEIRO, RJ Publicador: FUNDACO OSWALDO CRUZ; RIO DE JANEIRO, RJ
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.43%
A dimensional analysis of the classical equations related to the dynamics of vector-borne infections is presented. It is provided a formal notation to complete the expressions for the Ross' threshold theorem, the Macdonald's basic reproduction "rate" and sporozoite "rate", Garret-Jones' vectorial capacity and Dietz-Molineaux-Thomas' force of infection. The analysis was intended to provide a formal notation that complete the classical equations proposed by these authors.; European Union [282589]; European Union; LIM01 HCFMUSP; LIM01 HCFMUSP; CNPq; CNPq

Vectorial capacity, basic reproduction number, force of infection and all that: formal notation to complete and adjust their classical concepts and equations

Massad,Eduardo; Coutinho,Francisco Antonio Bezerra
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
Relevância na Pesquisa
66.43%
A dimensional analysis of the classical equations related to the dynamics of vector-borne infections is presented. It is provided a formal notation to complete the expressions for the Ross' Threshold Theorem, the Macdonald's basic reproduction "rate" and sporozoite "rate", Garret-Jones' vectorial capacity and Dietz-Molineaux-Thomas' force of infection. The analysis was intended to provide a formal notation that complete the classical equations proposed by these authors.

The assessment of insecticidal impact on the malaria mosquito's vectorial capacity, from data on the proportion of parous females

Garrett-Jones, C.; Grab, B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1964 EN
Relevância na Pesquisa
46.25%
In malaria eradication the residual insecticide exerts upon the mosquito's vectorial capacity a direct insecticidal impact, the order of which may be measured by observing the decrease in the proportion of parous females. The impact is expressed as the product of the degree of reduction of the expectation of infective life (termed the longevity factor of impact) and that of the expectation of life (the density factor). To compute the factors from the proportion parous it is necessary to know also the mean difference in age between the nulliparous and the youngest parous females in the sample, and the sporogonic period of the parasite.

Malaria vectorial capacity of a population of Anopheles gambiae: An exercise in epidemiological entomology

Garrett-Jones, C.; Shidrawi, G. R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1969 EN
Relevância na Pesquisa
46.25%
In order to assess the factors of malaria vectorial capacity and the daily reproduction rate, separate consideration is given to data from Kankiya, Northern Nigeria, concerning the incidence of vector—man contact (the man-biting rate), the vector's expectation of infective life, as reflected by the proportion of parous mosquitos under certain conditions, and the vector's man-biting habit, comprising the frequency of feeding and the human blood index. The main difficulty in the assessment of each of these factors was shown to be that of representative and adequate sampling, especially in a sprayed area. In order to compensate for deficiencies in the Kankiya data, especially with regard to the daily and cyclic survival-rates, the gonotrophic cycle and the effective sporogonic period, more complete published data on an Anopheles gambiae population in East Africa were examined, and extrapolations were made from these data in spite of the consequential risks involved.

Vectorial Capacity of Aedes aegypti: Effects of Temperature and Implications for Global Dengue Epidemic Potential

Liu-Helmersson, Jing; Stenlund, Hans; Wilder-Smith, Annelies; Rocklöv, Joacim
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 06/03/2014 EN
Relevância na Pesquisa
46.25%
Dengue is a mosquito-borne viral disease that occurs mainly in the tropics and subtropics but has a high potential to spread to new areas. Dengue infections are climate sensitive, so it is important to better understand how changing climate factors affect the potential for geographic spread and future dengue epidemics. Vectorial capacity (VC) describes a vector's propensity to transmit dengue taking into account human, virus, and vector interactions. VC is highly temperature dependent, but most dengue models only take mean temperature values into account. Recent evidence shows that diurnal temperature range (DTR) plays an important role in influencing the behavior of the primary dengue vector Aedes aegypti. In this study, we used relative VC to estimate dengue epidemic potential (DEP) based on the temperature and DTR dependence of the parameters of A. aegypti. We found a strong temperature dependence of DEP; it peaked at a mean temperature of 29.3°C when DTR was 0°C and at 20°C when DTR was 20°C. Increasing average temperatures up to 29°C led to an increased DEP, but temperatures above 29°C reduced DEP. In tropical areas where the mean temperatures are close to 29°C, a small DTR increased DEP while a large DTR reduced it. In cold to temperate or extremely hot climates where the mean temperatures are far from 29°C...

Assessment of insecticidal impact on the malaria mosquito's vectorial capacity, from data on the man-biting rate and age-composition

Molineaux, L.; Shidrawi, G. R.; Clarke, J. L.; Boulzaguet, J. R.; Ashkar, T. S.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1979 EN
Relevância na Pesquisa
46.43%
The reduction in average age of a vector population after application of a residual insecticide is commonly interpreted under the implicit assumption that the vector population is uniformly exposed to the insecticide. This assumption maximizes the calculated impact of the insecticide on the vectorial capacity. An alternative assumption, namely that the vector population is composed of two subpopulations, one endophilic and exposed, the other exophilic and not exposed, leads to a much smaller calculated impact of insecticide on the vectorial capacity. This is illustrated with data collected before and after application of propoxur in the Garki District, Kano State, Nigeria. These data were also used to estimate, on the one hand, before spraying, the proportion of blood meals taken by Anopheles gambiae s.l. on man that are followed by rest indoors, and on the other hand, after spraying, the proportion exposed after the first blood meal, according to the model of non-uniform exposure; the two estimates agree fairly well. The discussion compares the models of uniform and non-uniform exposure in terms of plausibility and concludes that the latter is more realistic. It is therefore prudent to take it into account when evaluating the impact of insecticides on the transmission of malaria.

An analysis of the vectorial capacity using moment-generating functions

Villela, Daniel A. M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/04/2015
Relevância na Pesquisa
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This paper describes a technique for analyzing the stochastic structure of the vectorial capacity using moment--generating functions. In such formulation, for an infectious disease transmitted by a vector, we obtain the generating function for the distribution of the number of infectious contacts (e.g., infectious bites from mosquitoes) between vectors and humans after a contact to a single infected individual. This approach permits us to generally derive the moments of the distribution and, under some conditions, derive the distribution function of the vectorial capacity. A stochastic modeling framework is helpful for analyzing the dynamics of disease spreading, such as performing sensitivity analysis.; Comment: 8 pages