Mycotoxin presentation
- 2. CONTENTS INTRODUCTION HISTORY EPIDEMIOLOGY TYPES DETECTION OF MYCOTOXINS PREVENTION AND CONTROL TREATMENT
- 3. INTRODUCTION Mycotoxins are low-molecular-weight secondary metabolites of fungi. These metabolites constitute a toxigenically and chemically heterogeneous assemblage that are grouped together only because the members can cause disease and death in human beings and other vertebrates. Mycotoxins are an important chronic dietary risk factor. They occur more frequently in areas with hot and humid climate, favorable for growth of molds; also found in temperate zones. The disease produced by mycotoxins are largely called as Mycotoxicoses.
- 4. HISTORY: An outbreak of aflatoxicosis was reported in 1974 in adjoining districts of gujarat and rajasthan Stachybotyrotoxicosis killed thousand of horses in 1930s in USSR In 1960, Aflatoxicosis alone killed about 1,00,000 young turks in the UK From 1960-1971 US military sprayed millions litres of toxic herbicides to destroy the vegetation used by liberation forces for cover and food
- 5. EPIDEMIOLOGY: Food stored for longer periods give fungi a greater opportunity to contaminate it Seen to be a significant cause of death in developed countries Based on the data given by Pitt and colleagues it was seen that a number of deaths caused by liver cancer were due to aflatoxins in Indonesia Acute fatalities have been reported in India caused by aflatoxin poisoning due to unseasonal rains
- 6. Factors Affecting Mycotoxin Production: Genetics , environmental and nutritional factors greatly affect the formation of Mycotoxins. Depending on the susceptibility of the crop, geographic and seasonal factors, as well as cultivation, harvesting, storage, and transportation practices, mycotoxins are found worldwide. In the field, weather conditions, plant stress, invertebrate vectors, species and spore load of infective fungi, variations within plant and fungal species, and microbial competition all significantly affect mycotoxin production.
- 7. 7 Physical factors such as time of exposure, temperature during exposure, humidity, and extent of insect or other damage to the commodity prior to exposure determine mycotoxin contamination in the field or during storage. Chemical factors including the nutritional status of the crops or chemicals (such as fungicides) used in crop management could affect fungal populations, and consequently toxin production In general, mycotoxins are optimally produced at 24– 28C, but some toxins such as T-2 toxin is maximally produced at 15C. Contamination during crop storage may be affected by changes in temperature and water activity, that allow ecological succession of different fungi as water activity Continue Factors Affecting…….
- 8. THE VARIOUS TYPES: The effects produced by fungi and their metabolites are categorised in two headings: 1. Mycotoxicoses 2. Mycetismus
- 9. MYCOTOXICOSES: Defined as the illness of man or domestic animal due to ingestion of pre formed substances on a particular food stuffs. Consumption of these toxins lead to fatal consequences. Most of the significant fungi producing mycotoxicosis mainly belong to toxigenic species of genera Aspergillus, Fusarium, and Penicillium Out of all the mycotoxins- aflatoxins, fusarium toxins and ochratoxins are considered to be significant in humans and animals
- 10. Production of mycotoxins depends upon factors like temperature, moisture, aeration and substrate on which the fungus is growing Most of the reported outbreaks of mycotoxicoses were found to be as consequence to consumption of food that is contaminated with mycotoxins There are four basic types: acute, chronic, mutagenic and teratogenic
- 11. These are a few medically important mycotoxins which produce distinctive diseases in man and animals: 1. Aflatoxins 2. Fumonisins 3. Tricothecenes 4. Ochratoxins 5. Cyclopyazonic acid 6. Zearalenone 7. Patulin
- 12. AFLATOXINS: Secondary metabolites produced by Aspergillus flavus Were discovered as strange manifestations of a mysterious disease called Turkey-X-disease Shows presence of B1, B2, G1 and G2 on the basis of their metabolites which exhibit blue (B), and green (G) fluorescence when irradiated under ultraviolet light on thin chromatography plates They can be modified by bio-transformation e.g. formation of hydroxylated derivates of aflatoxins B1 and B2 as aflatoxins M1 and M2 respectively
- 13. Mycotoxins effects on peanut and maize
- 14. CLINICAL MANIFESTATION: Aflatoxicosis Two forms are identified: acute severe intoxication, which results in direct liver damage and subsequent illness or death; chronic sub- symptomatic aflatoxicosis symptoms: lethargy, anorexia and muscle weakness and spasm Other manifestations include: fever, jaundice, hepatomegaly, ascites, portal hypertension, pedal edema and eventually death
- 15. REYE’S SYNDROME: Acute aflatoxicosis in which patient presents with signs and symptoms of encephalopathy and fatty degeneration of viscera Endemic disease of children in developing countries Also responsible for implicating outbreaks of hepatitis in India ICC (Indian childhood cirrhosis) is also caused by aflatoxins
- 16. PREVENTION Detoxification : Hydrated sodium calcium aluminosilicate (HSCAS) can absorb aflatoxins. Supportive : Vitamin .E & selenium. Prevention - Mold inhibitor - Treatment of grain with anhydrous ammonia for 10-14 days.
- 17. Fumonisins: Mycotoxin are toxic and carcinogenic secondary metabolites produced by many species of Fusarium. Common contaminant of maize and maize-based animal feeds throughout the world . The mycotoxin produced by fungi known as Fuomonisin B (FB1 to FB4 ) . These may cause fatal illness in some animals and are suspected to be human oesophageal carcinogens. High –performance liquid chromatography with fluorescent detection is the most widely used method.
- 18. TRICHOTHECENE: F. graminearum a pathogen of gramineous plants especially wheat is known to produce trichothecenes. The effect of the toxins are weight loss ,vomiting , feed refusal , dermatitis , diarrhoea , hemorrhages and necrosis of epithelium of stomach and intestine and Immunosuppression of lymphoid cells in thymus . Bone marrow , spleen testis and ovary.
- 19. OCHRATOXIN: OA causes renal toxicity, nephropathy and Immunosuppression in several species, and is carcinogenic in experimental animals. No data are available on absorption, distribution, metabolism and excretion of OA in humans.
- 20. CYCLOPYAZONIC ACID The CPA is a toxic indole tetramic acid derived from tryptophan , produces by the species genus of Aspergillus. It occurs naturally in agriculture products such as ground nuts and corn , mostly as co-contaminant with aflatoxin.
- 21. CLINICAL SYMPTOMS: Loss of weight Loss of appetite Weakness Vomiting Diarrhoea Dehydration Depression Convulsion and death
- 22. KODUA POISONING: Toxic syndrome in cattle and man often encountered in areas where kodo millet seed is consumed as staple food by poor people in several region of india. Eating of this grain result in giddiness , sleepiness and tremors recovering after 1 to 3 days.
- 23. ZEARALENONE: Zearalenone is an estrogenic toxin and it also produced by Fusarium species. This is found in variety of cereals like maize, barely, wheat grain etc. In humans it causes cervical cancer and precocious pubertal changes in children.
- 24. PATULIN: Patulin, is produced by many different molds but was first isolated as an antimicrobial active principle during the 1940s from Penicillium patulum. A number of early studies were directed towards harnessing its antibiotic activity. Patulin was toxic to both plants and animals, precluding its clinical use as an antibiotic. During the 1960s, patulin was reclassified as a mycotoxin.
- 25. MYCETISMUS:
- 26. Bioterrorism Mycotoxins can be used as chemical warfare agents .There is considerable evidence that Iraqi scientists developed aflatoxins as part of their bioweapons program during the 1980s. Aflatoxins seem a curious choice for chemical warfare because the induction of liver cancer is “hardly a knockout punch on the battlefield”. Unlike the aflatoxins, trichothecenes can act immediately upon contact, and exposure to a few milligrams of T-2 is potentially lethal.
- 27. 27 Detection and Screening of Mycotoxins: Because many steps are involved in the analysis, it is not uncommon that the analytical error can amount to 20–30% To obtain reliable analytical data, an adequate sampling program and an accurate analytical method are both important. To minimize the errors, studies have led to many improved and innovative analytical methods for mycotoxin analysis over the years. New, more sensitive TLC, HPLC, and GLC techniques are now available. New chemical methods, including capillary
- 28. ELISA RIA Spectrophotometry Tissue culture - Primary fetal bovine kidney cells Newer techniques have been used which include patterns of isoenzyme electrophoresis , DNA-DNA homology , restriction fragment length polymorphism.
- 29. PREVENTIVE MEASURES: 29 Management of Mycotoxin Contamination The economic implications of the mycotoxin problem and its potential health threat to humans have clearly created a need to eliminate or at least minimize mycotoxin contamination of food and feed. While an association between mycotoxin contamination and inadequate storage conditions has long been recognized, studies have revealed that seeds are contaminated with mycotoxins prior to harvest . Therefore, management of
- 30. TREATMENT: The main treatment is vigorous intravenous fluid replacement and correction of electrolyte disturbances and coagulopathy. Hameodialysis and hemoperfusion may be effective in removing toxin if initiated within 24 hrs of intake. Atropine is useful in mycetismus involving PNS in muscarine poisoning. Corticosteroids may prove useful and such patients should be given trails.