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Ethnobotanical study of some of mosquito repellent plants in north-eastern Tanzania.

Kweka EJ, Mosha F, Lowassa A, Mahande AM, Kitau J, Matowo J, Mahande MJ, Massenga CP, Tenu F, Feston E, Lyatuu EE, Mboya MA, Mndeme R, Chuwa G, Temu EA - Malar. J. (2008)

Bottom Line: Mortality induced by standard dosage of 30 mg/m2 on filter papers, scored after 24 hours was 47.3% for OK and 57% for OS, compared with 67.7% for citronella.The use of whole plants and their products as insect repellents is common among village communities of north-eastern Tanzania and the results indicate that the use of O. suave and O. kilimandscharicum as a repellent would be beneficial in reducing vector biting.The widespread use of this approach has a potential to complement other control measures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Tropical Pesticides Research Institute, Division of Livestock and Human Disease Vectors Control, P,O, Box 3024, Arusha,Tanzania. Pat.kweka@gmail.com

ABSTRACT

Background: The use of plant repellents against nuisance biting insects is common and its potential for malaria vector control requires evaluation in areas with different level of malaria endemicity. The essential oils of Ocimum suave and Ocimum kilimandscharicum were evaluated against malaria vectors in north-eastern Tanzania.

Methodology: An ethnobotanical study was conducted at Moshi in Kilimanjaro region north-eastern Tanzania, through interviews, to investigate the range of species of plants used as insect repellents. Also, bioassays were used to evaluate the protective potential of selected plants extracts against mosquitoes.

Results: The plant species mostly used as repellent at night are: fresh or smoke of the leaves of O. suave and O. kilimandscharicum (Lamiaceae), Azadirachta indica (Meliaceae), Eucalyptus globules (Myrtaceae) and Lantana camara (Verbenaceae). The most popular repellents were O. kilimandscharicum (OK) and O. suave (OS) used by 67% out of 120 households interviewed. Bioassay of essential oils of the two Ocimum plants was compared with citronella and DEET to study the repellence and feeding inhibition of untreated and treated arms of volunteers. Using filter papers impregnated with Ocimum extracts, knockdown effects and mortality was investigated on malaria mosquito Anopheles arabiensis and Anopheles gambiae, including a nuisance mosquito, Culex quinquefasciatus. High biting protection (83% to 91%) and feeding inhibition (71.2% to 92.5%) was observed against three species of mosquitoes. Likewise the extracts of Ocimum plants induced KD90 of longer time in mosquitoes than citronella, a standard botanical repellent. Mortality induced by standard dosage of 30 mg/m2 on filter papers, scored after 24 hours was 47.3% for OK and 57% for OS, compared with 67.7% for citronella.

Conclusion: The use of whole plants and their products as insect repellents is common among village communities of north-eastern Tanzania and the results indicate that the use of O. suave and O. kilimandscharicum as a repellent would be beneficial in reducing vector biting. The widespread use of this approach has a potential to complement other control measures.

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Biting success exhibited by three mosquito species treatments into twenty percent concentration of DEET, OK and OS.
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Figure 1: Biting success exhibited by three mosquito species treatments into twenty percent concentration of DEET, OK and OS.

Mentions: This present finding of cage experiments which compared the number of mosquitoes landed on treated and untreated arms of volunteers. The highest biting inhibition rate against all tested mosquito species was achieved by DEET (ranging from 88.7% to 92.5 %) followed by OS (83.5% to 88.9%) and OK (71.2% to 85.3%). Among the natural products tested, variation in biting inhibition within the species was observed; OS was more inhibiting for the An. gambiae s.s and An. arabiensis whereas the OK was efficient in inhibiting Cx. quinquefasciatus. The feeding inhibition caused by OS (P < 0.001) was significant higher than OK (P = 0.045) on both species of Anopheles tested. Likewise OK induced significant feeding inhibition on Cx. quinquefaciatus, but overall DEET gave the highest biting inhibition (Figure 1).


Ethnobotanical study of some of mosquito repellent plants in north-eastern Tanzania.

Kweka EJ, Mosha F, Lowassa A, Mahande AM, Kitau J, Matowo J, Mahande MJ, Massenga CP, Tenu F, Feston E, Lyatuu EE, Mboya MA, Mndeme R, Chuwa G, Temu EA - Malar. J. (2008)

Biting success exhibited by three mosquito species treatments into twenty percent concentration of DEET, OK and OS.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2519077&req=5

Figure 1: Biting success exhibited by three mosquito species treatments into twenty percent concentration of DEET, OK and OS.
Mentions: This present finding of cage experiments which compared the number of mosquitoes landed on treated and untreated arms of volunteers. The highest biting inhibition rate against all tested mosquito species was achieved by DEET (ranging from 88.7% to 92.5 %) followed by OS (83.5% to 88.9%) and OK (71.2% to 85.3%). Among the natural products tested, variation in biting inhibition within the species was observed; OS was more inhibiting for the An. gambiae s.s and An. arabiensis whereas the OK was efficient in inhibiting Cx. quinquefasciatus. The feeding inhibition caused by OS (P < 0.001) was significant higher than OK (P = 0.045) on both species of Anopheles tested. Likewise OK induced significant feeding inhibition on Cx. quinquefaciatus, but overall DEET gave the highest biting inhibition (Figure 1).

Bottom Line: Mortality induced by standard dosage of 30 mg/m2 on filter papers, scored after 24 hours was 47.3% for OK and 57% for OS, compared with 67.7% for citronella.The use of whole plants and their products as insect repellents is common among village communities of north-eastern Tanzania and the results indicate that the use of O. suave and O. kilimandscharicum as a repellent would be beneficial in reducing vector biting.The widespread use of this approach has a potential to complement other control measures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Tropical Pesticides Research Institute, Division of Livestock and Human Disease Vectors Control, P,O, Box 3024, Arusha,Tanzania. Pat.kweka@gmail.com

ABSTRACT

Background: The use of plant repellents against nuisance biting insects is common and its potential for malaria vector control requires evaluation in areas with different level of malaria endemicity. The essential oils of Ocimum suave and Ocimum kilimandscharicum were evaluated against malaria vectors in north-eastern Tanzania.

Methodology: An ethnobotanical study was conducted at Moshi in Kilimanjaro region north-eastern Tanzania, through interviews, to investigate the range of species of plants used as insect repellents. Also, bioassays were used to evaluate the protective potential of selected plants extracts against mosquitoes.

Results: The plant species mostly used as repellent at night are: fresh or smoke of the leaves of O. suave and O. kilimandscharicum (Lamiaceae), Azadirachta indica (Meliaceae), Eucalyptus globules (Myrtaceae) and Lantana camara (Verbenaceae). The most popular repellents were O. kilimandscharicum (OK) and O. suave (OS) used by 67% out of 120 households interviewed. Bioassay of essential oils of the two Ocimum plants was compared with citronella and DEET to study the repellence and feeding inhibition of untreated and treated arms of volunteers. Using filter papers impregnated with Ocimum extracts, knockdown effects and mortality was investigated on malaria mosquito Anopheles arabiensis and Anopheles gambiae, including a nuisance mosquito, Culex quinquefasciatus. High biting protection (83% to 91%) and feeding inhibition (71.2% to 92.5%) was observed against three species of mosquitoes. Likewise the extracts of Ocimum plants induced KD90 of longer time in mosquitoes than citronella, a standard botanical repellent. Mortality induced by standard dosage of 30 mg/m2 on filter papers, scored after 24 hours was 47.3% for OK and 57% for OS, compared with 67.7% for citronella.

Conclusion: The use of whole plants and their products as insect repellents is common among village communities of north-eastern Tanzania and the results indicate that the use of O. suave and O. kilimandscharicum as a repellent would be beneficial in reducing vector biting. The widespread use of this approach has a potential to complement other control measures.

Show MeSH
Related in: MedlinePlus