Spatial Clustering of Aedes aegypti Related to Breeding Container Characteristics in Coastal Ecuador: Implications for Dengue Control

Schafrick, Nathaniel H.; Milbrath, Meghan O.; Berrocal, Veronica J.; Wilson, Mark L.; Eisenberg, Joseph N. S.

doi:10.4269/ajtmh.12-0485

Cited by 26 publications

(24 citation statements)

References 22 publications

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“…The mosquito infection rates with dengue virus are of the order of 1% even in areas where transmission is ongoing [ 35 – 38 ]. Similar higher infection rates have been reported in a study in Merida, Mexico [ 39 ] and Odisha in India [ 40 ]. Although the mosquito infection rate in the current study was highest in Ilala followed by Temeke and Kinondoni, the incidence of dengue cases during the outbreak was highest in Kinondoni followed by Temeke and Ilala (Ministry of Health and Social Welfare, unpubl.).…”

Section: Discussionsupporting

confidence: 89%

The Risk of Dengue Virus Transmission in Dar es Salaam, Tanzania during an Epidemic Period of 2014

et al. 2016

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BackgroundIn 2010, 2012, 2013 and 2014 dengue outbreaks have been reported in Dar es Salaam, Tanzania. However, there is no comprehensive data on the risk of transmission of dengue in the country. The objective of this study was to assess the risk of transmission of dengue in Dar es Salaam during the 2014 epidemic.Methodology/Principal FindingsThis cross-sectional study was conducted in Dar es Salaam, Tanzania during the dengue outbreak of 2014. The study involved Ilala, Kinondoni and Temeke districts. Adult mosquitoes were collected using carbon dioxide-propane powered Mosquito Magnet Liberty Plus traps. In each household compound, water-holding containers were examined for mosquito larvae and pupae. Dengue virus infection of mosquitoes was determined using real-time reverse transcription polymerase chain reaction (qRT-PCR). Partial amplification and sequencing of dengue virus genome in infected mosquitoes was performed. A total of 1,000 adult mosquitoes were collected. Over half (59.9%) of the adult mosquitoes were collected in Kinondoni. Aedes aegypti accounted for 17.2% of the mosquitoes of which 90.6% were from Kinondoni. Of a total of 796 houses inspected, 38.3% had water-holding containers in their premises. Kinondoni had the largest proportion of water-holding containers (57.7%), followed by Temeke (31.4%) and Ilala (23.4%). The most common breeding containers for the Aedes mosquitoes were discarded plastic containers and tires. High Aedes infestation indices were observed for all districts and sites, with a house index of 18.1% in Ilala, 25.5% in Temeke and 35.3% in Kinondoni. The respective container indices were 77.4%, 65.2% and 80.2%. Of the reared larvae and pupae, 5,250 adult mosquitoes emerged, of which 61.9% were Ae. aegypti. Overall, 27 (8.18) of the 330 pools of Ae. aegypti were positive for dengue virus. On average, the overall maximum likelihood estimate (MLE) indicates pooled infection rate of 8.49 per 1,000 mosquitoes (95%CI = 5.72–12.16). There was no significant difference in pooled infection rates between the districts. Dengue viruses in the tested mosquitoes clustered into serotype 2 cosmopolitan genotype.Conclusions/SignificanceAe. aegypti is the main vector of dengue in Dar es Salaam and breeds mainly in medium size plastic containers and tires. The Aedes house indices were high, indicating that the three districts were at high risk of dengue transmission. The 2014 dengue outbreak was caused by Dengue virus serotype 2. The high mosquito larval and pupal indices in the area require intensification of vector surveillance along with source reduction and health education.

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Section: Discussionsupporting

confidence: 89%

The Risk of Dengue Virus Transmission in Dar es Salaam, Tanzania during an Epidemic Period of 2014

et al. 2016

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“…Five studies examined the occurrence and correlates of domiciliary and peri-domicilliary mosquito density, including sociodemographic characteristics, container types, and meteorological correlates [73–77]. Specifically, Rodrigues et al [73] and Serpa et al [77] studied Aedes aegypti and Aedes albopictus , and Favaro et al [74], Morales-Pérez et al [75] and Schafrick et al [76] studied Aedes aegypti . Covered containers [75–77], low education of the household head [75] and higher densities of residents per household [73] were found to be associated with higher risk of infestation.…”

Section: Resultsmentioning

confidence: 99%

“…Low socioeconomic status and related factors, including poor infrastructure, inconsistent access to water, and high household resident density, have been consistently with arbovirus vector occurrence [73–76,90], suggesting that socioeconomic development may be an important means of vector-borne disease prevention.…”

Section: Discussionmentioning

confidence: 99%

Arbovirus Vectors of Epidemiological Concern in the Americas: A Scoping Review of Entomological Studies on Zika, Dengue and Chikungunya Virus Vectors

Jones

Kulkarni

Davidson

et al. 2019

Preprint

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27 Background 28 Three arthorpod-borne viruses (arboviruses) causing human disease have been the focus 29 of a large number of studies in the Americas since 2013 due to their global spread and 30 epidemiological impacts: Zika, dengue, and chikungunya viruses. A large proportion of 31 infections by these viruses are asymptomatic. However, all three viruses are associated with 32 moderate to severe health consequences in a small proportion of cases. Two mosquito species, 33 Aedes aegypti and Aedes albopictus, are among the world's most prominent arboviral vectors, 34 and are known primary vectors for all three viruses in the Americas. 35 Objectives 2 36 This review summarizes the state of the entomological literature surrounding the biology 37 and ecology of vectors of Zika, dengue and chikungunya viruses and factors affecting virus 38 transmission. The rationale of the review was to elucidate consensus and discord between 39 studies, and guide future research based on identified knowledge gaps. 40 Results 41 A total of 196 studies were included in the scoping review after initial screening and 42 subsequent exclusion of out-of-scope studies, secondary data publications, duplicate records, and 43 studies unavailable in English language. 44 Key findings 45 Temperature and humidity have the strongest impact on mosquito distribution and 46 dynamics, development of immatures and arborviral infection rates. Low socioeconomic status 47 and related factors, including poor infrastructure, inconsistent access to water, and high 48 household resident density, have been consistently associated with arbovirus vector occurrence. 49 Effects of interspecific competition on arboviral vector species is currently poorly understood. 50 Vector competence for Zika virus is well established for Ae. aegypti and Ae. albopictus. 51 Information on Zika virus vector transmission dynamics is sparse in contrast to the wealth of 52 research available for dengue and chikungunya viruses. 53 Conclusions 54Based on the internationally recognized urgency of Zika virus infection as a public health 55 concern, further research on arbovirus vectors and transmission dynamics is of pressing need. 56 57

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“…In general, the Pacific coast and the Amazon basin lowlands present climatic, ecological and socio-economic conditions that favor the establishment of Ae. aegypti populations (Schafrick et al 2013), and consequently important outbreaks of Zika, dengue and chikungunya (MSP 2018).…”

Section: Introductionmentioning

confidence: 99%

Genetic variation ofAedes aegyptipopulations from Ecuador

Cevallos¹,

Benítez²,

Coloma³

et al. 2019

Preprint

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33This is the first genetic analysis in Ecuador of Aedes aegypti using fragments of mitochondrial 34 genes, NADH dehydrogenase subunit 4 (ND4) and cytochrome oxidase subunit I (COI). A total 35 of 154 mosquitoes from 23 localities were collected in the Pacific coastal lowlands, Amazon 36 basin lowlands, and the Galápagos Islands from 2012 to 2019. The analysis of fragments of the 37 genes COI (672 bp) and ND4 (262 bp) and concatenated analysis of both COI and ND4 showed 38 two haplotypes (H1, H2) present in Ecuador mainland and the Galápagos Islands. The 39 phylogenetic analysis identified two well-supported clades. Combined analysis of both genes 40 from ten localities also resulted in two haplotypes. Nucleotide diversity, neutrality tests 41 (Tajima´s test D, Fu and Li´s F*and D*) and AMOVA analysis of the entire data set suggest 42 balancing selection for both genes. The results indicate genetic variation without geographical 43 restriction. COI-H1 grouped with sequences from the Americas, West and Central Africa, East 44 Africa, Asia, and Australia. ND4-H1 grouped with similar sequences from the Americas, Asia 45 and West Africa. COI-H2 grouped with sequences from Asia and the Americas. ND4-H2 46 grouped with sequences from the Americas. We report overlapping peaks in four sequences that 47 suggest heteroplasmy in the individuals. The origin of the populations of Aedes aegypti in 48Ecuador show African genetic origin and are widely present in several countries in the Americas. 49

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Spatial Clustering of Aedes aegypti Related to Breeding Container Characteristics in Coastal Ecuador: Implications for Dengue Control

Cited by 26 publications

References 22 publications

The Risk of Dengue Virus Transmission in Dar es Salaam, Tanzania during an Epidemic Period of 2014

The Risk of Dengue Virus Transmission in Dar es Salaam, Tanzania during an Epidemic Period of 2014

Arbovirus Vectors of Epidemiological Concern in the Americas: A Scoping Review of Entomological Studies on Zika, Dengue and Chikungunya Virus Vectors

Genetic variation ofAedes aegyptipopulations from Ecuador

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