Distribution and seasonality of vertically transmitted dengue viruses in Aedes mosquitoes in arid and semi-arid areas of Rajasthan, India
Background & objectives: Transovarial transmission of dengue virus is a crucial etiological phenomenon responsible for persistence of virus during inter-epidemic period of the disease. Distribution and seasonality of this phenomenon in disease endemic areas may contribute to explain emergence of...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Wolters Kluwer Medknow Publications
2008-02-01
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| Series: | Journal of Vector Borne Diseases |
| Subjects: | |
| Online Access: | http://www.mrcindia.org/journal/issues/451056.pdf |
| _version_ | 1818537969855758336 |
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| author | Bennet Angel Vinod Joshi |
| author_facet | Bennet Angel Vinod Joshi |
| author_sort | Bennet Angel |
| collection | DOAJ |
| description | Background & objectives: Transovarial transmission of dengue virus is a crucial etiological phenomenon responsible for persistence of virus during inter-epidemic period of the disease. Distribution and seasonality of this phenomenon in disease endemic areas may contribute to explain emergence of dengue and its subsequent prevention. The study on seasonal and area distribution of transovarial transmission of dengue virus in Aedes aegypti, Ae. albopictus and Ae. vittatus has been made in desert and non-desert districts of Rajasthan, India from 2006 to 2007. The observations revealed role of different Aedes species in transmission and retention of dengue virus.Methods: The larvae of Ae. aegypti, Ae. albopictus and Ae. vittatus were collected during each of the study seasons from rural and urban areas of three districts—Jodhpur, Jaipur and Kota. The larvae were collected from domestic and peri-domestic containers and from tree holes of peri-urban foci such as gardens and parks and were reared into adults in the laboratory at room temperature. The laboratory reared adults were subjected to Indirect fluorescence antibody test (IFAT). The laboratory-reared adult mosquitoes showing positive IFA were treated as the sample showing vertically transmitted dengue virus.Results: Pooled data for all the four seasons revealed maximum (15.7%) mosquito infectivity in Ae. albopictus followed by Ae. aegypti (12.6%) in Jodhpur district. In Jaipur district, Ae. vittatus showed highest infection (20%) of vertically transmitted virus followed by Ae. albopictus (18.7%) and least in Ae. aegypti (13.3%). In Kota district, pooled data for all the four seasons showed maximum vertical infection of mosquitoes in Ae. albopictus (14.2%).Interpretation & conclusion: Transovarial transmission of dengue virus by available vector species in a dengue endemic setting could be the key etiological phenomenon responsible for re-emergence of the disease from inter-epidemic to epidemic phase of disease onset. The observations in the present study suggest that during winter season which is not the active transmission season of dengue in Rajasthan, Ae. albopictus has shown maximum percentage of vertically transmitted virus. Our observation substantiates with the earlier studies that how Ae. albopictus is horbouring virus during inter-epidemic period of dengue. Another important lead emerging through present study is the high mosquito infectivity of Ae. aegypti during summer and rainy seasons especially from desert districts, Jodhpur and semi district. This observation suggests that in Rajasthan, owing to tendency of overstorage of domestic water by the inhabitants, mosquito and vertically transmitted virus get pronounced during summer season which could precedes the active transmission season of dengue during following rainy season. |
| first_indexed | 2024-12-11T18:57:34Z |
| format | Article |
| id | doaj.art-209f86745628425295e0e5245c60e9b9 |
| institution | Directory Open Access Journal |
| issn | 0972-9062 |
| language | English |
| last_indexed | 2024-12-11T18:57:34Z |
| publishDate | 2008-02-01 |
| publisher | Wolters Kluwer Medknow Publications |
| record_format | Article |
| series | Journal of Vector Borne Diseases |
| spelling | doaj.art-209f86745628425295e0e5245c60e9b92022-12-22T00:54:06ZengWolters Kluwer Medknow PublicationsJournal of Vector Borne Diseases0972-90622008-02-014515659Distribution and seasonality of vertically transmitted dengue viruses in Aedes mosquitoes in arid and semi-arid areas of Rajasthan, IndiaBennet AngelVinod JoshiBackground & objectives: Transovarial transmission of dengue virus is a crucial etiological phenomenon responsible for persistence of virus during inter-epidemic period of the disease. Distribution and seasonality of this phenomenon in disease endemic areas may contribute to explain emergence of dengue and its subsequent prevention. The study on seasonal and area distribution of transovarial transmission of dengue virus in Aedes aegypti, Ae. albopictus and Ae. vittatus has been made in desert and non-desert districts of Rajasthan, India from 2006 to 2007. The observations revealed role of different Aedes species in transmission and retention of dengue virus.Methods: The larvae of Ae. aegypti, Ae. albopictus and Ae. vittatus were collected during each of the study seasons from rural and urban areas of three districts—Jodhpur, Jaipur and Kota. The larvae were collected from domestic and peri-domestic containers and from tree holes of peri-urban foci such as gardens and parks and were reared into adults in the laboratory at room temperature. The laboratory reared adults were subjected to Indirect fluorescence antibody test (IFAT). The laboratory-reared adult mosquitoes showing positive IFA were treated as the sample showing vertically transmitted dengue virus.Results: Pooled data for all the four seasons revealed maximum (15.7%) mosquito infectivity in Ae. albopictus followed by Ae. aegypti (12.6%) in Jodhpur district. In Jaipur district, Ae. vittatus showed highest infection (20%) of vertically transmitted virus followed by Ae. albopictus (18.7%) and least in Ae. aegypti (13.3%). In Kota district, pooled data for all the four seasons showed maximum vertical infection of mosquitoes in Ae. albopictus (14.2%).Interpretation & conclusion: Transovarial transmission of dengue virus by available vector species in a dengue endemic setting could be the key etiological phenomenon responsible for re-emergence of the disease from inter-epidemic to epidemic phase of disease onset. The observations in the present study suggest that during winter season which is not the active transmission season of dengue in Rajasthan, Ae. albopictus has shown maximum percentage of vertically transmitted virus. Our observation substantiates with the earlier studies that how Ae. albopictus is horbouring virus during inter-epidemic period of dengue. Another important lead emerging through present study is the high mosquito infectivity of Ae. aegypti during summer and rainy seasons especially from desert districts, Jodhpur and semi district. This observation suggests that in Rajasthan, owing to tendency of overstorage of domestic water by the inhabitants, mosquito and vertically transmitted virus get pronounced during summer season which could precedes the active transmission season of dengue during following rainy season.http://www.mrcindia.org/journal/issues/451056.pdfAedesIndiatransovarial transmission |
| spellingShingle | Bennet Angel Vinod Joshi Distribution and seasonality of vertically transmitted dengue viruses in Aedes mosquitoes in arid and semi-arid areas of Rajasthan, India Journal of Vector Borne Diseases Aedes India transovarial transmission |
| title | Distribution and seasonality of vertically transmitted dengue viruses in Aedes mosquitoes in arid and semi-arid areas of Rajasthan, India |
| title_full | Distribution and seasonality of vertically transmitted dengue viruses in Aedes mosquitoes in arid and semi-arid areas of Rajasthan, India |
| title_fullStr | Distribution and seasonality of vertically transmitted dengue viruses in Aedes mosquitoes in arid and semi-arid areas of Rajasthan, India |
| title_full_unstemmed | Distribution and seasonality of vertically transmitted dengue viruses in Aedes mosquitoes in arid and semi-arid areas of Rajasthan, India |
| title_short | Distribution and seasonality of vertically transmitted dengue viruses in Aedes mosquitoes in arid and semi-arid areas of Rajasthan, India |
| title_sort | distribution and seasonality of vertically transmitted dengue viruses in aedes mosquitoes in arid and semi arid areas of rajasthan india |
| topic | Aedes India transovarial transmission |
| url | http://www.mrcindia.org/journal/issues/451056.pdf |
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