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Epidemic risk of arboviral diseases:Determining the habitats, spatial-temporal distribution, and abundance of immature Aedes aegypti in the Urban and Rural areas of Zanzibar, Tanzania
- Source :
- Saleh, F, Kitau, J, Konradsen, F, Kampango, A, Abassi, R & Schiøler, K L 2020, ' Epidemic risk of arboviral diseases : Determining the habitats, spatial-temporal distribution, and abundance of immature Aedes aegypti in the Urban and Rural areas of Zanzibar, Tanzania ', PLOS Neglected Tropical Diseases, vol. 14, no. 12, e0008949 . https://doi.org/10.1371/journal.pntd.0008949, PLoS Neglected Tropical Diseases, Vol 14, Iss 12, p e0008949 (2020), PLoS Neglected Tropical Diseases
- Publication Year :
- 2020
-
Abstract
- Background In Zanzibar, little is known about the arboviral disease vector Aedes aegypti in terms of abundance, spatio-temporal distribution of its larval habitats or factors associated with its proliferation. Effective control of the vector requires knowledge on ecology and habitat characteristics and is currently the only available option for reducing the risk of arboviral epidemics in the island nation of Zanzibar. Methodology We conducted entomological surveys in households and surrounding compounds from February to May 2018 in the urban (Mwembemakumbi and Chumbuni) and rural (Chuini and Kama) Shehias (lowest government administrative unit) situated in the Urban-West region of Unguja island, Zanzibar. Larvae and pupae were collected, transported to the insectary, reared to adult, and identified to species level. Characteristics and types of water containers were also recorded on site. Generalized linear mixed models with binomial and negative binomial distributions were applied to determine factors associated with presence of Ae. aegypti immatures (i.e. both larvae and pupae) or pupae, alone and significant predictors of the abundance of immature Ae. aegypti or pupae, respectively. Results The survey provided evidence of widespread presence and abundance of Ae. aegypti mosquitoes in both urban and rural settings of Unguja Island. Interestingly, rural setting had higher numbers of infested containers, all immatures, and pupae than urban setting. Likewise, higher House and Breteau indices were recorded in rural compared to the urban setting. There was no statistically significant difference in Stegomyia indices between seasons across settings. Plastics, metal containers and car tires were identified as the most productive habitats which collectively produced over 90% of all Ae. aegypti pupae. Water storage, sun exposure, vegetation, and organic matter were significant predictors of the abundance of immature Ae. aegypti. Conclusions Widespread presence and abundance of Ae. aegypti were found in rural and urban areas of Unguja, the main island of Zanzibar. Information on productive habitats and predictors of colonization of water containers are important for the development of a routine Aedes surveillance system and targeted control interventions in Zanzibar and similar settings.<br />Author summary Dengue is considered the most important mosquito-borne viral disease and a global public health threat. In recent decades, large scale epidemics of dengue have occurred across sub-Saharan Africa including mainland Tanzania. Aedes aegypti is identified as the principal vector for dengue transmission in most affected countries. In the absence of antiviral treatment and as a dengue vaccine is not readily available; dengue prevention depends largely on vector control. As mosquitoes develop resistance towards commonly applied chemical insecticides, environmental management targeting the destruction of larval habitats is recommended. In Zanzibar, little is known about Ae. aegypti in terms of type, magnitude, or distribution of its larval habitats. In this study, we identified the main larval habitats of Ae. aegypti, their seasonal variations and factors contributing to Ae. aegypti abundance across urban and rural settings of Unguja Island in Zanzibar. We found widespread presence and abundance of the vector with plastic and metal containers as well as car tires identified as the most important larval habitats. Season, location of water container, water storage, sun exposure, presence of vegetation and organic matter were among the factors associated with high Ae. aegypti abundance. This study is the first to document widespread occurrence and distribution of Ae. aegypti in Zanzibar and highlights the need for the establishment of a nation-wide Aedes surveillance program to guide the development and monitoring of targeted, context specific vector control interventions for prevention of dengue and other arboviral epidemics. Aedes surveillance involves periodic inspection of households and surrounding environments for presence of larvae/pupae in water-holding containers which are then targeted for larval source reduction, as well as monitoring of adult mosquito populations.
- Subjects :
- Rural Population
0301 basic medicine
Life Cycles
Viral Diseases
Entomology
RC955-962
Disease Vectors
Tanzania
Mosquitoes
Dengue Fever
Geographical Locations
Medical Conditions
Larvae
0302 clinical medicine
Aedes
Abundance (ecology)
Arctic medicine. Tropical medicine
Medicine and Health Sciences
Larva
Ecology
Pupa
Eukaryota
Habitats
Insects
Infectious Diseases
Habitat
Arboviral Infections
Seasons
Public aspects of medicine
RA1-1270
Research Article
Neglected Tropical Diseases
Risk
animal structures
Arthropoda
030231 tropical medicine
Mosquito Vectors
Aedes aegypti
Aedes Aegypti
Arbovirus Infections
Biology
03 medical and health sciences
Spatio-Temporal Analysis
Animals
Humans
Epidemics
Ecosystem
Ecology and Environmental Sciences
fungi
Organisms
Public Health, Environmental and Occupational Health
Biology and Life Sciences
Pupae
Tropical Diseases
biology.organism_classification
Invertebrates
Insect Vectors
Species Interactions
030104 developmental biology
Vector (epidemiology)
People and Places
Africa
Rural area
Zoology
Developmental Biology
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Saleh, F, Kitau, J, Konradsen, F, Kampango, A, Abassi, R & Schiøler, K L 2020, ' Epidemic risk of arboviral diseases : Determining the habitats, spatial-temporal distribution, and abundance of immature Aedes aegypti in the Urban and Rural areas of Zanzibar, Tanzania ', PLOS Neglected Tropical Diseases, vol. 14, no. 12, e0008949 . https://doi.org/10.1371/journal.pntd.0008949, PLoS Neglected Tropical Diseases, Vol 14, Iss 12, p e0008949 (2020), PLoS Neglected Tropical Diseases
- Accession number :
- edsair.doi.dedup.....fff742c1185a9a0fddda33a564a78b9e