Transcript DEVELOPMENT OF A BIOPESTICIDE AND A MOSQUITO

DEVELOPMENT OF A BIOPESTICIDE AND A MOSQUITO
REPELLENT BASED ON SELECTED PLANTS IN KENYA
Proposal submitted in partial fulfillment of requirements for doctor of philosophy
degree of university of Nairobi (Pharmacology and Toxicology)
Investigator : Joseph Kisivo Musau BscN, Msc UoN
Supervisors : Dr. James M. Mbaria BVM, Msc, PhD UoN
: Dr Joseph M. Nguta, BVM, Msc, PHD UoN
: Dr Mbaabu Mathiu, BVM, PhD Hawaii
: Prof. Stephen G. Kiama, BVM, Msc, PhD Berne
INTRODUCTION
Mosquitoes bites cause nuisance, allergy, dermatitis
and secondary infections
 They are Vectors for malaria, Filariasis and
arboviruses
 Mosquitoes of greatest importance to human are
Anopheles and Culex.
Current control methods are biological, physical and
chemical
Emphasis is on personal control
Jahn et al (2010) ;Kitchen et al (2009); Tolle, (2009).
Personal control
Indoor residual spraying: Insect resistance
ITN’s: Insect resistance
Repellent treated clothing: Expensive
Use of repellents: Suitable, Appropriate, Easy.
But synthetic ones :Expensive, Safety
concerns
Jahn et al (2010) ; Maniafu et al (2009); USAID
(2011).
LITERATURE REVIEW
Life cycle of a mosquito
Female mosquitoes need blood meal for
development of eggs
• They are attracted to hosts by body odour,
heat, carbon dioxide and lactic acid
As they bite, they transmit diseases eg:
Malaria, Filariasis, Yellow Fever
Jahn et al (2010); Tolle, (2009).
Aedes aegypti
Mosquito bites
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Burden of mosquito transmitted
diseases
Malaria
Affects 500m people in the world with resultant 1.5 M deaths
Dengue
Affects 50-100 million people with 20% of them dying
Rift valley fever
Endemic in Africa and middle east. Resulted in human illness and loss of
livestock in Kenya
Filariasis
The subject of a global eradication campaign directed by the WHO
West Nile virus
Endemic in the Americas
 Others: Yellow fever (Africa and the Americas), Chikungunya (East Africa),
O’nyongnyong (East Africa), West Nile virus (the Americas), Japanese
encephalitis (Australasia/India)
Ogoma et al (2010), Tolle, (2009); WHO, (2009)
Mosquito control
 Biological:
• Predators - fish, nematodes, pathogens:
 Physical/mechanical
• Impossible: cannot eliminate aquatic habitats
 Chemical control
• Diesel and kerosene
• Organochlorine insecticides and larvicides
 Personal protection
• Nets : Bed nets, netting material on the doors etc
• Insecticides in aerosol canisters
 Insect repellents : Effective for temporary control. Only
means available where mosquitoes bite early in the
evening / early in the morning.
Ogoma et al (2010) ; Service, (1986); Moore, (2004)
Historical use of plants as mosquito repellents
 Ancient Egypt
• Plants were hanged at doors, windows
 Greek and Romans: The Geoponika of 6th century: Plant with
insect repellent Artemisia absinthium, Cassia spp, Ficus carica,
Allium sativum and Citrus medica
 Kenya
• O. americanum, L. camara and L. ukambensis, C. citriodora and O.
suave hanged in houses or burnt.
 Despite the long usage and advantages of plant derived
repellents there is little effort to investigate and promote the
traditional use of plant-derived natural repellents
Moore,(2004); Seyoum et al (2002)
Studying insect repellents
In vitro: Easy, no risk to human subjects. Do
not mimic the conditions of repellent usage
In vivo: Data not representative on
performance of the repellent on human
Laboratory studies: Human volunteers
Field studies: Evaluated in human volunteers
in and around houses
Moore et al (2004); WHO,(1996); WHO,(2009)
Objectives of the study
Overall objective: to asses repellency and larvicidal
activity of selected plants with aim of developing a
mosquito repellent preparation from these plants
Specific objectives
1. Perform acute dermal irritation/corrosion test
according to laid down procedures
2. Evaluate mosquito repellent activity of the selected
plants
3. Assess larvicidal activity of the selected plants
4. Develop a suitable mosquito repellent from the
selected plants that is safe and efficacious to use
Justification
Repellents supplement bed nets when people are
outdoors
Synthetic insecticides and larvicides:
 Development of resistance; DEET : Toxic
Plant based repellents and larvicides :
Affordable, culturally acceptable
Boosts economy of locals
Not likely to lead to insect resistance
Safe
Current plant based natural repellents require
several re-applications
MATERIALS AND METHODS
Study area: study to be conducted at Msambweni District, Kwale County
Selection of plants
 Based on available and relevant literature Ameen et al
(2011); Kokwaro (1993); Muthaura et al (2011);
Nguta et al (2010)
 Identification and authentication to be done at
University of Nairobi Herbarium, Nguta et al (2010)
Sources: Abubakar et al (2011); Kokwaro (1993); Muthaura et al (2011); Nguta et al
(2010)
Family
Plant species
Life form
Part used
Anacardiaceae
Heeria insignis Del.
Tree
Stem
Bombacacea
Adansonia digitata Linn.
Tree
Leaves
Compositae
Launea cornuta (Oliv andHiern) C.Jeffrey
Herb
Leaves
Cyperaceae
Cyperus articulatus L.
Herb
Rhizome
Rubiaceae,
Canthium glaucum Hiern
Shrub
Fruit
Rutaceae,
Zanthoxylum chalybeum (Eng) Engl
Tree
Root
Simaroubaceae
Harrisonia abyssinica Oliv.
Shrub
Root, leaf
Solanacea
Solanum incanum L
Shrub
Root , leaf
Labiatae
Ocimum suave
Herb
leaf
Meliacea
Azadirachta indica
Tree
Root, leaf
Asteraceae
Tagetus minuta
Tree
leaf
Labiatae
Plectranthus barbatus
Shrub
Leaves
Verbenaceae
Lantana camara L
Shrub
Leaves
Tiliaceae
Grewia trichocarpa Hochst ex A.Rich
Shrub
Root
Azadirachta indica - Neem
Heeria insignis leaves and stem
Preparation of plant material
Ground plant material will be stored in airtight
containers and extracted with acetone and
water
Aqueous extracts will be freeze dried
Organic extracts will be dried at 400 C in oven
Anees, A (2008)
 Acute dermal test
• Performed before testing for repellency on human skin
• Procedure will be performed as laid down in OECD guidelines,
404.
OECD,(2002).
 Mosquito repellency tests:
 Arm in cage
• Will be conducted with female Aedes aegypti on volunteers’
arms
• Test substances: plant extract in liquid paraffin with acetone
• Negative control: liquid paraffin with acetone
• Positive control: DEET (N, N,-diethyl-3 methyl toulamide) in
liquid paraffin with acetone as solvent will be positive control.
WHO,1996,2009
A fabricated cage for mosquito breeding, taken at the insectary at department of
botany/zoology ,Chiromo
 Susceptibility bioassays
• Mosquito will be exposed to filter papers treated with
different dosages of plant extracts
• Untreated filter papers will be -ve control and +ve
control, Citronella oil
Time taken to knock down 90% of the population
(KD90) and 95% confidence interval will be
calculated per treatment
Kweka et al (2008).
Contact bioassays
• Netting material treated with dosages of
extracts will be used
• 5 starved female mosquitoes will be exposed
to treated material for 3 minutes.
They will be observed for mortality and
recovery within 24 hours.
Kweka et al( 2008); Mullai et al( 2008).
Larvicidal activity testing
• Test will be carried out on 3rd and 4th instar larvae
• larvae will be exposed to 250 ml of test concentration.
Mortality will be recorded after 24 h and determined
using Abbott’s formula
LC50 and LC90 will be calculated using probit analysis
Ansari et al (2005); Finney, (1971); Maniafu et al
(2009);WHO, (1981)
Development of a mosquito repellent
 Extract(s) with the most activity and least irritant will be
compounded and formulated into a cream
 Extracts will be prepared in a cream base containing
 Glyceryl monostearate (5% w/w)
 Sodium lauryl sulphate (3% w/w)
 Cetostearyl alcohol (2% w/w)
 Liquid paraffin B.P. (25% w/w)
 Distilled water (to 100%)
 And compounded with the help of a local and established
pharmaceutical manufacturer
 Considerations will be made for patency /registration
Work plan
Activity
Year 1
Month
1-4
Literature review, PhD registration
and proposal write up
Collection of plant material
Preparation of plant material
Acute dermal irritation test
Mosquito repellency tests
Larvicidal activity tests
Development of a mosquito repellent
Data entry
Analysis of data and results
Publication
Thesis writing and submission
5-8
Year 2
9-12 1-4
5-8
Year 3
9-12 1-4
5-8
9-12
BUDGET ESTIMATES
ACTIVITY
AMOUNT(Kshs)
Registration and university fees
450000
Proposal write up and familiarization with laboratory 50,000
techniques
Collection of plant materials
150,000
Drying of plant material, grinding ,freeze-drying
Extraction of plant material
Acute dermal irritation/corrosion test
60,000
200,000
75,000
Mosquito repellency tests
150,000
Larvicidal activity tests
200,000
Development of a mosquito repellent
150,000
Analysis of results, thesis write up and submission
Total
150,000
1435000
15% contingency/inflation over 3-year period
215250
Grand total
1650250
ACKNOWLEDGEMENTS
God
The Carnegie Corporation, New York Through
RISE-AFNNET (University of Nairobi node)
The Node Coordinator, Prof. S. G Kiama for
accepting to sponsor me for this study
My Supervisors
All in Attendance