Want to understand: (1) How does the scientific process helps us solve health problems? (2) What are aflatoxins? Are they relevant to human and animal health? (3) How do organisms’ interactions with each other and their environment influence disease?

4 spp. shown to produce toxins: A. flavus A. parasiticus A. nomius A. niger

4 major aflatoxins M2M2 2 metabolic products

Aflatoxin distribution Exposure mainly from: – A. flavus: global distribution, produces B classes of aflatoxins –A. parasiticus: Africa and the Americas, produces B and G classes of aflatoxins

Partial list of foods: Cereals –maize, sorghum, millet, rice, wheat Oil seeds –groundnut, soybean, sunflower, cotton Tree nuts –pistachio, almond, walnut, coconut Spices –paprika, chile, black pepper, coriander, turmeric, ginger Figs Milk, cheese, meat, eggs

Pre-harvest risk factors: –High temperatures –Chronic drought –Heavy rains –Crop insect damage –Poor fertility –Weed competition –High crop densities

Post-harvest risk factors: –High temperatures –Humidity

Liver function One of the largest internal organs Produces bile used to digest food Metabolizes carbohydrates and lipids Stores glycogen (for energy), key nutrients Breaks down toxic substances

Cytochrome P450 oxidase: Found in high densities in liver Oxidative enzymes that modify and degrade toxins Absorb light at 450 nm

Bioactivation: Enzymes can convert a chemical into something even more reactive or toxic Ex.: Ethanol  via Alcohol dehydrogenase  Acetaldehyde

Williams, J.H., T.D Phillips, P.E. Jolly, J.K Stiles and D. Agga Human aflatoxicosis in developing countries: a review of toxicology, exposure, potential health consequences, and interventions. Am. J. Clin. Nutr.Nov;80(5):

No aflatoxin Highest dose Rat livers

Toxicology Acute aflatoxicosis –high dosage over short time –hemorrhage –acute liver damage –edema –altered digestion, absorption, and metabolism –death

Toxicology Chronic aflatoxicosis –impaired food conversion –slower growth –immunity problems –cirrhosis –liver cancer

Documented outbreaks 1974, rural NW India: 397 ill, 108 dead High fever, jaundice, ascites Preceded by same symptoms in dogs Traced to maize w/ major A. flavus infestation Chronic drought, unseasonable rain, poor storage, ignorance of dangers of moldy food

Documented outbreaks 1981, rural Kenya: 20 hospitalizations, 12 deaths Abdominal discomfort, anorexia, malaise, fever, jaundice, dark urine Doves died, then dogs ill, then people ill Contaminated maize Heavy rains, drought, and protein- deficient diets thought to contribute

1) The scientific process is investigative and helps us solve health problems (2) Aflatoxins are fungal toxins that pose serious risks to human and animal health (3) Organisms’ interactions with each other and their environment determine whether or not disease outbreak occurs