Aflatoxins and Aflasafe
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Aflatoxins Aflasafe Highly toxic metabolite produced by Aspergillus flavus and related fungi Most toxic compound found in nature The fungus infects crops and produces the toxin in the field and in stores Maize and groundnut are most vulnerable; other crops are susceptible Contamination possible without visible signs of the fungus Impact on health and trade
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Aflatoxins and Aflasafe
- 1. www.iita.org Alejandro Ortega, IITA On behalf of the Aflasafe team A member of CGIAR consortium 16-18 March, 2016 www.iita.org Aflatoxins and Aflasafe
- 2. www.iita.org Aflatoxin: what is it? • Highly toxic metabolite produced by Aspergillus flavus and related fungi • Most toxic compound found in nature • The fungus infects crops and produces the toxin in the field and in stores • Maize and groundnut are most vulnerable; other crops are susceptible • Contamination possible without visible signs of the fungus • Impact on health and trade A member of CGIAR consortium 16-18 March, 2016 www.iita.org What are aflatoxins?
- 3. www.iita.org Aspergillus flavus morphotypes Aflatoxin-producing fungi A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 4. www.iita.org Aflatoxin contamination and the disease triangle A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 5. www.iita.org Vegetative compatibility groups (VCGs) in theVegetative compatibility groups (VCGs) in the AspergilliAspergilli Variation within species A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 6. www.iita.org Taiwan 1967 Malaysia 1988 Western India 1974 Kenya 1982 2002 2004 2005 2006 History of aflatoxicosis outbreaksHistory of aflatoxicosis outbreaks A member of CGIAR consortium 16-18 March, 2016 www.iita.org Slide prepared by C. ProbstSlide prepared by C. Probst
- 7. www.iita.org Aflatoxicosis = Aflatoxin Poisoning Chronic Aflatoxicosis Ingestion of low to moderate levels of aflatoxins Symptoms: - Impaired food conversion - Stunting - Immune suppression - Liver cancer Acute Aflatoxicosis Ingestion of moderate to high levels of aflatoxins Symptoms: - Acute liver damage - Abdominal swelling - Acute hepatitis - Death - Death www.aspergillus.org.uk A member of CGIAR consortium 16-18 March, 2016 www.iita.orgA member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 8. www.iita.org Aflatoxin, Health & Trade Death (>200 people in Kenya) Synergistic with Hepatitis B Virus (HBV) to cause liver cancer • 30 times more potent in HBV+ people • 5-60 times higher cancer risk Suppress immune system – increased susceptibility to diseases, e.g., HIV Animal productivity reduced – growth rate, embryo toxicity, feed efficiency, cancer, death…… Trade impact -- >US$1.2 billion loss A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 9. www.iita.org Aflatoxin exposure and stunting • Stunting: 40% more frequent in the high exposure zone • Exposure: mother to baby before (umbilical cord) and after (breast milk) birth, and maize-based diets after weaning 28% A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 10. www.iita.org Prevalence of aflatoxins in food • High levels from Kenya, Benin, Burkina Faso, Cameroon, Gambia, Ghana, Mozambique, Nigeria, Senegal, Zambia……. • Frequency of occurrence high – >30% maize in stores with >20 ppb aflatoxin – ~90% stores are contaminated with Aflatoxin-producing fungi – Up to 40% grain in households with aflatoxin • Several African staple commodities affected • Causes: environmental conditions, traditional farming methods improper grain drying and storage practices, unregulated markets A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 11. www.iita.org Food systems Large Scale and Regulated – Developed countries – Trade based – Advanced infrastructure – Capital intensive Small Scale and Unregulated – Developing countries – Informal markets – Subsistence – High food insecurity A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 12. www.iita.orgA member of CGIAR consortium 16-18 March, 2016 www.iita.org Situation in developing countries
- 13. www.iita.org Synergistic interaction with Hepatitis-B & C MalnutritionMalnutrition Liver cancerLiver cancer Trade Restrictions Trade Restrictions Quality reductionQuality reduction Aflatoxin contamination in food and feed Reduced ability to cope with diseases, especially HIV/AIDS Liver cirrhosis, immuno-suppression, blocks nutrient absorption, growth abnormalities, etc. Vicious-Link Vicious-Link TRADETRADE HEALTH HEALTH Aflatoxins—the vicious link A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 14. www.iita.org Aflatoxin management strategies • Awareness • Resistant varieties • Biological control • Timely harvest • Rapid grain drying • Storage structure • Sorting and processing • Insect control A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 15. www.iita.org Biological control of aflatoxins • Fungal communities differ in aflatoxin-producing ability • Some strains produce aflatoxins and others no aflatoxin (atoxigenic) - naturally occurring atoxigenic can be exploited as biocontrol agents A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 16. www.iita.org Biological control of aflatoxins • Competitive exclusion: atoxigenic strains displace toxigenic strains - Shift strain profile from toxigenic to atoxigenic • Effects in multiple crops, areas, and years • IITA has conducted activities related to biocontrol of aflatoxins since 2003 A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 17. www.iita.org Spores Aflasafe in 2.5 & 5 kg bags Wind Soil colonization and displacement of toxigenic fungi Sporulation on moist soil 3-20 days How does aflasafe work? Broadcast @ 10 kg/ha 2-3 weeks before flowering 30-33 grains/m2 A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 18. www.iita.orgA member of CGIAR consortium 16-18 March, 2016 www.iita.org Before biocontrol application
- 19. www.iita.orgA member of CGIAR consortium 16-18 March, 2016 www.iita.org After biocontrol application
- 20. www.iita.org Recovery of released strains from soil an grain of control and treated plots 0 10 20 30 40 50 60 70 80 90 Control Treated Recoveryofreleased atoxigenicstrains(%) Soil before inoculation Soil at harvest Grain at harvest 60-80% carry-over of inoculum one year after application A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 21. www.iita.orgwww.iita.orgA member of CGIAR consortiumA member of CGIAR consortium 16-17 March, 2016 www.iita.org Aflasafe, how it was developed? Over 10 years of research • Collection and identification of isolates - Over 5,000 individuals of Aspergillus flavus - Identification of atoxigenic strains native to major producing areas of Nigeria - Reasons of inability to produce aflatoxins • Tests to ensure biosafety of the atoxigenic isolates • Development of methods for mass production of aflasafe • Efficacy trials in farmer fields
- 22. www.iita.orgwww.iita.orgA member of CGIAR consortium Production of Aflasafe Agriculture for Nutrition &A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 23. Nigeria: efficacy on maize 82 94 83 86 82 93 89 90 51 14 199 38 51 14 166 38Fields (#) Less (%) At HarvestAt Harvest After StorageAfter Storage Aflatoxin(ppb) A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 24. www.iita.orgA member of CGIAR consortium 82 94 82 93 16 82 16 81Fields (#) At HarvestAt Harvest After storageAfter storage Aflatoxin(ppb) Nigeria: efficacy on groundnut A member of CGIAR consortium 16-18 March, 2016 www.iita.org Less (%)
- 25. www.iita.org Benefits of using aflasafe Short term •Significantly lower aflatoxin contamination in aflasafe-treated crops; safe crops available for local consumption by households •Food and feed industries will have access to good quality maize and groundnut for manufacturing safe and nutritious products A member of CGIAR consortium 16-17 March, 2016 www.iita.org
- 26. www.iita.org Benefits of using aflasafe Long term •Improved health and nutrition of people, especially women and children •Increased livestock productivity and profitability due to incorporation of aflatoxin-reduced crops in the feed value chain •Greater trading opportunities in domestic, regional, and international premium markets = Higher income for farmers/aggregators/traders A member of CGIAR consortium 16-17 March, 2016 www.iita.org
- 27. www.iita.orgwww.iita.orgA member of CGIAR consortium Aflasafe development in Africa Senegal Burkina Faso Ghana Nigeria Kenya Tanzania Mozambique Zambia Rwanda Burundi Uganda The Gambia Malawi Strain development in progress Products under testing in farmers’ fields Product ready for registration Product registered Agriculture for Nutrition &A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 28. www.iita.orgwww.iita.orgA member of CGIAR consortium Commercialization & tech transfer Agriculture for Nutrition & Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Nigeria Kenya Senegal/Gambia Zambia BurkinaFaso Ghana Mozambique Tanzania Malawi Uganda 2016 2017 2018 2019 2020 Key Complete Product Registration Develop Country Strategy Submit Country Strategy for Approval Develop Manufacturing/Distribution Parnerships Submit Tech Transfer Agreements for Approval Provide Support, Monitor for Quality and Usage A member of CGIAR consortium 16-18 March, 2016 www.iita.org
- 29. www.iita.org IITA Campus, Ibadan A member of CGIAR consortium 16-18 March, 2016 www.iita.org
Hinweis der Redaktion
- But what is the fungi causing contamination in Mexico, (four states of Mexico)? In fact, across certain regions of Mexico. A. flavus, the most common aflatot producer, as I mentioned before, has 2 main morphotypes, S & L strains, which differ in morphological, physiological and genetic criteria. S strain produces numerous, small sclerotia, few conidia and consistently high levels of B1, the L strain produces fewer, larger sclerotia, copious conidia and variable levels of B1. Some L strain isolates do not produce any detectable amount of aflat Other species were found including A. nomius, A. parasiticus and Local species, but these species were found in low frequencies and are infrequently associated with maize production. These produce G aflatoxins.
- Large variability in several aspects, including epidemiology, physiology, aflatoxin production. Mention that is the main reason why we focus in the L strain,LARGE VARIABILITY IN AFLATOXIN PRODUCING POTENTIALS. ● Aspergillus species are subdivided in clonal lineages known as Vegetative Compatibility Groups or VCGs. These may differ to a great extent in several characteristics, including aflatoxin-production, crop adaptation, among others. + VCGs were assessed using nitrate nonutilizing mutants in VCA ● in this tests, A tester pair of a VCG is placed to react ● with a mutant of an isolate of interest. Heterokaryon formation will occur only between isolates w/ identical alleles at each loci governing VC, indicating that isolates belong to the same VCG. As great diversity exists in each morphotype and species, a mixture of VCGs can be interacting in an area, in single fields, even single maize ears. Members of a VCG are typically considered to be descendants of th e same clonal linear and to contain one of the two highly distinct mating-type genes
- Serious threat for countries where maize production are located in areas conducive to aflatoxin accumulation. Esta otra figura representa los paises que han sufrido de brotes de aflatoxicosis que han resultado en decenas de muertes, siendo el mas reciente el caso de kenya en el 2006. Pero cuantos de estos casos se han presentado en otros paises y no se han dado a conocer por diversos factores?
- Biological control agents act against plant pathogens through different modes of action. Antagonistic interactions that can lead to biological control include antibiosis, competition and hyperparasitism. Competition occurs when two or more microorganisms require the same resources in excess of their supply. These resources can include space, nutrients, and oxygen. In a biological control system, the more efficient competitor, i.e., the biological control agent, out-competes the less efficient one, i.e., the pathogen. Antibiosis occurs when antibiotics or toxic metabolites produced by one microorganism have direct inhibitory effect on another. Hyperparasitism or predation results from biotrophic or necrotrophic interactions that lead to parasitism of the plant pathogen by the biological control agent. Some microorganisms, particularly those in soil, can reduce damage from diseases by promoting plant growth or by inducing host resistance against a myriad of pathogens. Efficient biological control agents often express more than one mode of action for suppressing the plant pathogens.
- Biological control agents act against plant pathogens through different modes of action. Antagonistic interactions that can lead to biological control include antibiosis, competition and hyperparasitism. Competition occurs when two or more microorganisms require the same resources in excess of their supply. These resources can include space, nutrients, and oxygen. In a biological control system, the more efficient competitor, i.e., the biological control agent, out-competes the less efficient one, i.e., the pathogen. Antibiosis occurs when antibiotics or toxic metabolites produced by one microorganism have direct inhibitory effect on another. Hyperparasitism or predation results from biotrophic or necrotrophic interactions that lead to parasitism of the plant pathogen by the biological control agent. Some microorganisms, particularly those in soil, can reduce damage from diseases by promoting plant growth or by inducing host resistance against a myriad of pathogens. Efficient biological control agents often express more than one mode of action for suppressing the plant pathogens.
- En este campo de maiz pueden ver que existen muchos individuos productores de toxinas en el aire, la planta, o en suelo. * Afortunadamente, tambien existen hongos dentro de esta misma seccion fungica que no las producen y que pueden ser utilizados como agentes de biocontrol para reducir la contaminacion. La mayoria de estos grupos de individuos que no producen toxinas son altamente competitivos, por lo que desplazan a los individuos toxicos y ocupan los lugares que estos ocuparian.
- Una vez aplicdo el producto en el campo, la cantidad de individuos beneficos se incrementa y los niveles de aflatoxinas se reducen a niveles permitidos por las agencias alrededor del mundo.
- Aflasafe is a biopesticide developed by IITA and USDA-ARS and registered by NAFDAC for aflatoxin mitigation in maize and groundnut in Nigeria. The demonstration-scale manufacturing aflasafe facility, funded by the Bill & Melinda Gates Foundation under the aegis of Partnership for Aflatoxin Control in Africa, was built in 2014 to supply aflasafe to farmers. This is the largest aflatoxin biocontrol product manufacturing plant and has the highest production throughput in the world. Nigerian farmers are purchasing aflasafe to treat their maize fields. Aflasafe (www.aflasafe.com) is packaged in 2.5 kg and 5 kg bags and available for sale at IITA’s Business Incubation Platform.