Insecticide resistance in <it>Culex quinquefasciatus </it>from Zanzibar: implications for vector control programmes
<p>Abstract</p> <p>Background</p> <p>Zanzibar has a long history of lymphatic filariasis (LF) caused by the filarial parasite <it>Wuchereria bancrofti</it>, and transmitted by the mosquito <it>Culex quinquefasciatus </it>Say. The LF Programme in...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2012-04-01
|
| Series: | Parasites & Vectors |
| Subjects: | |
| Online Access: | http://www.parasitesandvectors.com/content/5/1/78 |
| _version_ | 1828523998937350144 |
|---|---|
| author | Jones Christopher M Machin Camille Mohammed Khalfan Majambere Silas Ali Abdullah S Khatib Bakari O Mcha Juma Ranson Hilary Kelly-Hope Louise A |
| author_facet | Jones Christopher M Machin Camille Mohammed Khalfan Majambere Silas Ali Abdullah S Khatib Bakari O Mcha Juma Ranson Hilary Kelly-Hope Louise A |
| author_sort | Jones Christopher M |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Zanzibar has a long history of lymphatic filariasis (LF) caused by the filarial parasite <it>Wuchereria bancrofti</it>, and transmitted by the mosquito <it>Culex quinquefasciatus </it>Say. The LF Programme in Zanzibar has successfully implemented mass drug administration (MDA) to interrupt transmission, and is now in the elimination phase. Monitoring infections in mosquitoes, and assessing the potential role of interventions such as vector control, is important in case the disease re-emerges as a public health problem. Here, we examine <it>Culex </it>mosquito species from the two main islands to detect <it>W. bancrofti </it>infection and to determine levels of susceptibility to the insecticides used for vector control.</p> <p>Methods</p> <p><it>Culex </it>mosquitoes collected during routine catches in Vitongoji, Pemba Island, and Makadara, Unguja Island were tested for <it>W. bancrofti </it>infection using PCR. Insecticide bioassays on <it>Culex </it>mosquitoes were performed to determine susceptibility to permethrin, deltamethrin, lambda-cyhalothrin, DDT and bendiocarb. Additional synergism assays with piperonyl butoxide (PBO) were used for lambda-cyhalothrin. Pyrosequencing was used to determine the <it>kdr </it>genotype and sequencing of the mitochondrial cytochrome oxidase I (mtCOI) subunit performed to identify ambiguous <it>Culex </it>species.</p> <p>Results</p> <p>None of the wild-caught <it>Culex </it>mosquitoes analysed were found to be positive for <it>W. bancrofti</it>. High frequencies of resistance to all insecticides were found in Wete, Pemba Island, whereas <it>Culex </it>from the nearby site of Tibirinzi (Pemba) and in Kilimani, Unguja Island remained relatively susceptible. Species identification confirmed that mosquitoes from Wete were <it>Culex quinquefasciatus</it>. The majority of the <it>Culex </it>collected from Tibirinzi and all from Kilimani could not be identified to species by molecular assays. Two alternative <it>kdr </it>alleles, both resulting in a L1014F substitution were detected in <it>Cx. quinquefasciatus </it>from Wete with no homozygote susceptible detected. Metabolic resistance to pyrethroids was also implicated by PBO synergism assays.</p> <p>Conclusions</p> <p>Results from the xenomonitoring are encouraging for the LF programme in Zanzibar. However, the high levels of pyrethroid resistance found in the principle LF vector in Pemba Island will need to be taken into consideration if vector control is to be implemented as part of the elimination programme.</p> |
| first_indexed | 2024-12-11T20:38:11Z |
| format | Article |
| id | doaj.art-d8edb1cc8637422aacf5e33c1d558daf |
| institution | Directory Open Access Journal |
| issn | 1756-3305 |
| language | English |
| last_indexed | 2024-12-11T20:38:11Z |
| publishDate | 2012-04-01 |
| publisher | BMC |
| record_format | Article |
| series | Parasites & Vectors |
| spelling | doaj.art-d8edb1cc8637422aacf5e33c1d558daf2022-12-22T00:51:35ZengBMCParasites & Vectors1756-33052012-04-01517810.1186/1756-3305-5-78Insecticide resistance in <it>Culex quinquefasciatus </it>from Zanzibar: implications for vector control programmesJones Christopher MMachin CamilleMohammed KhalfanMajambere SilasAli Abdullah SKhatib Bakari OMcha JumaRanson HilaryKelly-Hope Louise A<p>Abstract</p> <p>Background</p> <p>Zanzibar has a long history of lymphatic filariasis (LF) caused by the filarial parasite <it>Wuchereria bancrofti</it>, and transmitted by the mosquito <it>Culex quinquefasciatus </it>Say. The LF Programme in Zanzibar has successfully implemented mass drug administration (MDA) to interrupt transmission, and is now in the elimination phase. Monitoring infections in mosquitoes, and assessing the potential role of interventions such as vector control, is important in case the disease re-emerges as a public health problem. Here, we examine <it>Culex </it>mosquito species from the two main islands to detect <it>W. bancrofti </it>infection and to determine levels of susceptibility to the insecticides used for vector control.</p> <p>Methods</p> <p><it>Culex </it>mosquitoes collected during routine catches in Vitongoji, Pemba Island, and Makadara, Unguja Island were tested for <it>W. bancrofti </it>infection using PCR. Insecticide bioassays on <it>Culex </it>mosquitoes were performed to determine susceptibility to permethrin, deltamethrin, lambda-cyhalothrin, DDT and bendiocarb. Additional synergism assays with piperonyl butoxide (PBO) were used for lambda-cyhalothrin. Pyrosequencing was used to determine the <it>kdr </it>genotype and sequencing of the mitochondrial cytochrome oxidase I (mtCOI) subunit performed to identify ambiguous <it>Culex </it>species.</p> <p>Results</p> <p>None of the wild-caught <it>Culex </it>mosquitoes analysed were found to be positive for <it>W. bancrofti</it>. High frequencies of resistance to all insecticides were found in Wete, Pemba Island, whereas <it>Culex </it>from the nearby site of Tibirinzi (Pemba) and in Kilimani, Unguja Island remained relatively susceptible. Species identification confirmed that mosquitoes from Wete were <it>Culex quinquefasciatus</it>. The majority of the <it>Culex </it>collected from Tibirinzi and all from Kilimani could not be identified to species by molecular assays. Two alternative <it>kdr </it>alleles, both resulting in a L1014F substitution were detected in <it>Cx. quinquefasciatus </it>from Wete with no homozygote susceptible detected. Metabolic resistance to pyrethroids was also implicated by PBO synergism assays.</p> <p>Conclusions</p> <p>Results from the xenomonitoring are encouraging for the LF programme in Zanzibar. However, the high levels of pyrethroid resistance found in the principle LF vector in Pemba Island will need to be taken into consideration if vector control is to be implemented as part of the elimination programme.</p>http://www.parasitesandvectors.com/content/5/1/78Lymphatic filariasisMalariaVector controlInsecticide resistanceZanzibar |
| spellingShingle | Jones Christopher M Machin Camille Mohammed Khalfan Majambere Silas Ali Abdullah S Khatib Bakari O Mcha Juma Ranson Hilary Kelly-Hope Louise A Insecticide resistance in <it>Culex quinquefasciatus </it>from Zanzibar: implications for vector control programmes Parasites & Vectors Lymphatic filariasis Malaria Vector control Insecticide resistance Zanzibar |
| title | Insecticide resistance in <it>Culex quinquefasciatus </it>from Zanzibar: implications for vector control programmes |
| title_full | Insecticide resistance in <it>Culex quinquefasciatus </it>from Zanzibar: implications for vector control programmes |
| title_fullStr | Insecticide resistance in <it>Culex quinquefasciatus </it>from Zanzibar: implications for vector control programmes |
| title_full_unstemmed | Insecticide resistance in <it>Culex quinquefasciatus </it>from Zanzibar: implications for vector control programmes |
| title_short | Insecticide resistance in <it>Culex quinquefasciatus </it>from Zanzibar: implications for vector control programmes |
| title_sort | insecticide resistance in it culex quinquefasciatus it from zanzibar implications for vector control programmes |
| topic | Lymphatic filariasis Malaria Vector control Insecticide resistance Zanzibar |
| url | http://www.parasitesandvectors.com/content/5/1/78 |
| work_keys_str_mv | AT joneschristopherm insecticideresistanceinitculexquinquefasciatusitfromzanzibarimplicationsforvectorcontrolprogrammes AT machincamille insecticideresistanceinitculexquinquefasciatusitfromzanzibarimplicationsforvectorcontrolprogrammes AT mohammedkhalfan insecticideresistanceinitculexquinquefasciatusitfromzanzibarimplicationsforvectorcontrolprogrammes AT majamberesilas insecticideresistanceinitculexquinquefasciatusitfromzanzibarimplicationsforvectorcontrolprogrammes AT aliabdullahs insecticideresistanceinitculexquinquefasciatusitfromzanzibarimplicationsforvectorcontrolprogrammes AT khatibbakario insecticideresistanceinitculexquinquefasciatusitfromzanzibarimplicationsforvectorcontrolprogrammes AT mchajuma insecticideresistanceinitculexquinquefasciatusitfromzanzibarimplicationsforvectorcontrolprogrammes AT ransonhilary insecticideresistanceinitculexquinquefasciatusitfromzanzibarimplicationsforvectorcontrolprogrammes AT kellyhopelouisea insecticideresistanceinitculexquinquefasciatusitfromzanzibarimplicationsforvectorcontrolprogrammes |