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Aflatoxin infection

Category: Illness or disabilities

Type

Involuntary

Introduction and description

 

Aflatoxins are naturally occurring mycotoxins that are produced by Aspergillus flavus and Aspergillus parasiticus, species of fungi.  Thus this is one type of fungal infection, and a very serious one.  Aflatoxins are toxic and among the most carcinogenic substances known.

Aflatoxin-producing members of Aspergillus are common and widespread in nature. They can colonize and contaminate grain before harvest or during storage. Host crops, which include maize, sorghum, and groundnuts, are particularly susceptible to infection by Aspergillus following prolonged exposure to a high-humidity environment, or damage from stressful conditions such as drought.

Commercial peanut butter, cooking oils (e.g. olive, peanut and sesame oil), and cosmetics have been identified as contaminated with aflatoxin.  In some instances, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and other analytical methods, revealed a range from 48% to 80% of selected product samples as containing detectable quantities of aflatoxin.

 

Aflatoxins have been isolated from all major cereal crops, and even from cannabis. The staple commodities regularly contaminated with aflatoxins include cassava, chillies, corn, cotton seed, millet, peanuts, rice, sorghum, sunflower seeds, tree nuts, wheat, and a variety of spices intended for human or animal consumption. When processed, aflatoxins get into the general food supply where they have been found in both pet and human foods, as well as in feedstocks for agricultural animals. Aflatoxin transformation products are sometimes found in eggs, milk products, and meat when animals are fed contaminated grains.

No animal species is immune to the acute toxic effects of aflatoxins, however, adult humans have a higher tolerance for aflatoxin exposure than children and animals and ‘rarely succumb to acute aflatoxicosis’.  This said, in 2003, 120 people died in Kenya after eating maize with very high aflatoxin levels.

 

Furthermore, a large number of diseases may be attributable to the presence of aflatoxins simply because aflatoxin B1 can cause immune suppression, leaving the door open to other pathogens.  They act, in other words, like a form of immunosuppressant and since immunosuppressants have caused upwards of 50,000 deaths in the USA, this fungi may be responsible for many more.

Symptoms

Liver damage

The main target organ in mammals is the liver, so aflatoxicosis primarily is a hepatic disease. High-level aflatoxin exposure produces an ‘acute hepatic necrosis’, resulting later in cirrhosis, or carcinoma of the liver. Acute liver failure is made manifest by bleeding, oedema, alteration in digestion, changes to the absorption and/or metabolism of nutrients, and mental changes and/or coma.

Pain

Chronic, subclinical exposure does not lead to symptoms so dramatic as acute aflatoxicosis. The principal symptom is pain.

Hepatitis

........ Hepatitis B is an example of an infectious agent functioning as an acquired susceptibility factor. Hepatitis B synergistically increases the risk of hepatocellular carcinoma when accompanied by exposure to aflatoxin, a relationship that may be modified by constitutive risk factors, such as epoxide hydrolase capabilities. Acquired risk factors have the potential to greatly influence risk and their impact should be included in future studies of the health effects of environmental toxicants. PMID: 21781823

in effect the immune reducing effects of the aflatoxin cause the person to be suseptible to hepatitis, then the combination of hepatitis and aflatoxin produce cancer.

Cancer

 

Chronic exposure leads to a high risk of developing liver cancer, as aflatoxin metabolites may intercalate into DNA and alkylate the bases through epoxide moiety. This is thought to cause mutations in the p53 gene, an important gene in preventing cell cycle progression when there are DNA mutations, or signaling apoptosis (programmed cell death). These mutations seem to affect some base pair locations more than others, for example, the third base of codon 249 of the p53 gene appears to be more susceptible to aflatoxin-mediated mutations than nearby bases.

Stunted growth and mental retardation

Children are particularly affected by aflatoxin exposure, which leads to stunted growth and delayed development.  These effects may be observed in children, but also the fetus in the womb

Some studies showed significant relationship between exposure of aflatoxin B1 (4 mg/kg, single dose) and teratogenesis (the appearance of developmental anomalies) in hamsters.

Reye’s syndrome

 

Aflatoxins are implicated in some cases of Reye’s syndrome.  Reye syndrome or Reye's syndrome is a rapidly progressive encephalopathy which usually begins shortly after recovery from an acute viral illness, especially influenza and varicella (chickenpox). It is a potentially fatal syndrome that has numerous detrimental effects on many organs, especially the brain and liver, as well as causing hyperammonemia (elevated blood ammonia level) and low blood sugar. The classic features are a rash, vomiting, and liver damage. The exact cause is unknown, however, one of the causes may be aflatoxin infection resulting in immunosuppression and thus enabling the other diseases to gain  a hold

In order to reinvestigate a strong reported association, we attempted to identify aflatoxin in the livers of 12 children who possibly died of Reye's Syndrome and in the liver of one child who died accidentally [sic]. Aflatoxins were detected, but not confirmed in only one of the liver specimens (limits of detection 20 ppt). ….. We conclude that aflatoxin is not regularly recoverable from cases of Reye's Syndrome at a high rate  PMID:  4004347

In other words, it is one possible cause.

Asthma and allergies

The contamination of food and feed by Aspergillus has become a global issue with a significant worldwide economic impact. The growth of Aspergillus is unfavourable to the development of food and feed industries, where the problems happen mostly due to the presence of mycotoxins, which is a toxic metabolite secreted by most Aspergillus groups. Moreover, fungi can produce spores that cause diseases, such as allergies and asthma, especially to human beings. High temperature, high moisture, retarded crops, and poor food storage conditions encourage the growth of mold, as well as the development of mycotoxins. A variety of chemical, biological, and physical strategies have been developed to control the production of mycotoxins. A biological approach, using a mixed culture comprised of Saccharomyces cerevisiae and Lactobacillus rhamnosus resulted in the inhibition of the growth of fungi when inoculated into fermented food. The results reveal that the mixed culture has a higher potential (37.08%) to inhibit the growth of Aspergillus flavus (producer of Aflatoxin) compared to either single culture, L. rhamnosus NRRL B-442 and S. cerevisiae, which inhibit the growth by 63.07% and 64.24%, respectively.  PMID: 25269603

 

 Death

Children and animals are more likely to die than adult humans, although as mentioned above the immunosuppressive effects of aflatoxin could result in longer term problems in adults.

Turkeys are extremely susceptible to aflatoxicosis. Recent studies have revealed that this is due to the efficient cytochrome P450 mediated metabolism of aflatoxin B1 in the liver of turkeys and deficient glutathione-S-transferase mediated detoxification. The mechanistic understanding of the susceptibility of turkeys to aflatoxin B1 is very relevant since turkeys are important from an agricultural and food standpoint.

Causes

At least 14 different types of aflatoxin are produced in nature. Aflatoxin B1 is considered the most toxic and is produced by both Aspergillus flavus and Aspergillus parasiticus. Aflatoxin G1 and G2 are produced exclusively by A. parasiticus. While the presence of Aspergillus in food products does not always indicate that harmful levels of aflatoxin also are present, it does imply a significant risk in consumption. Aflatoxins M1, M2 originally were discovered in the milk of cows that fed on mouldy grain. These compounds are products of a conversion process in the animal's liver, however, aflatoxin M1 is present in the fermentation broth of Aspergillus parasiticus.

  • Aflatoxin B1 & B2, produced by Aspergillus flavus and A. parasiticus
  • Aflatoxin G1 & G2, produced by Aspergillus parasiticus
  • Aflatoxin M1, metabolite of aflatoxin B1 in humans and animals (exposure in ng levels may come from a mother's milk)
  • Aflatoxin M2, metabolite of aflatoxin B2 in milk of cattle fed on contaminated foods
  • Aflatoxicol
  • Aflatoxin Q1 (AFQ1), major metabolite of AFB1 in in vitro liver preparations of other higher vertebrates

Diagnosis

There are two principal techniques that have been used most often to detect levels of aflatoxin in humans.

  • AFB1-guanine  - The first method is measuring the AFB1-guanine adduct in the urine of subjects. The presence of this breakdown product indicates exposure to aflatoxin B1 during the past 24 hours. This technique measures only recent exposure, however. Due to the half-life of this metabolite, the level of AFB1-guanine measured may vary from day to day, based on diet, it is not ideal for assessing long-term exposure.
  • AFB1-albumin  - Another technique that has been used is a measurement of the AFB1-albumin adduct level in the blood serum. This approach provides a more integrated measure of exposure over several weeks or months.

Prevention

You cannot eradicate aspergillus, it is everywhere and it serves a purpose in Nature, which is essential.  The native habitat of Aspergillus is in soil, decaying vegetation, hay, and grains undergoing microbiological deterioration, in effect its purpose in Nature is to help in the breakdown of decaying vegetation.

Improve storage conditions

The key is to avoid creating the conditions where crops or food substances are stored for long periods in damp warm conditions.  ‘Favourable conditions’ for fungal growth are high moisture content (at least 7%) and high temperature. Thus one way of preventing infection is not just to keep the environment dry, and to dry the crops well, but to find a way of lowering the temperature close to freezing.

 

Don’t eat food that is old or mouldy

 It is also an invitation to eat freshly harvested food and not food stored for long periods, which is bound to deteriorate, because that is Nature’s way.

Never eat mouldy food.  Don’t try to cut out the mouldy bits, as some mould will be visible and some not, the mould is capable of creeping all over the food undetected.

Flush your house

Aflatoxin B1 can permeate through the skin. Dermal exposure to this aflatoxin in particular environmental conditions may lead to serious health risks.  There appears to be additional evidence that the spores can also be inhaled.  So ensure that your fridge is clean and free from mould and that your house is well ventilated and mould free.

Perhaps allow one day where you open all your windows turn off the heating and let the wind sweep through to clear the air of all pathogens.

 

Change doggy’s food

Aflatoxin has potential to lead to liver disease in dogs. As with any toxic exposure, development of aflatoxicosis is a dose-related occurrence. Some dogs who develop liver disease will recover. Those exposed to large doses for extended periods may not.  Thus if your dog shows even the slightest hint of distress after eating his dog food, change the dog food – immediately.

I guess the same can be said for us too.  If we are ill after food, let the supplier know, but don’t eat it again.  And don’t do this expecting compensation, this is the wrong motive.  Do it because you want to ensure others are not ill, like you.

Rigorous monitoring and honesty

Suppliers and manufacturers of food need extremely rigorous monitoring procedures in place to ensure their products are not contaminated.

In 2005, Diamond Pet Foods discovered aflatoxin in a product manufactured at their facility in Gaston, South Carolina. In 23 states, Diamond voluntarily recalled 19 products formulated with corn and manufactured in the Gaston facility. Testing of more than 2,700 finished product samples conducted by laboratories confirmed that only two date codes of two adult dog formulas with the "Best By" dates of April 3, April 4, April 5, and April 11 had the potential to be toxic.

This is honesty at its best.

Treatment

Ultimately the best treatment is food and plants with antiaflatoxin activity.  We have provided a number of observations showing which plants are active against this toxic fungi.  Spraying food products with anti-fungals is not the answer, the anti-fungals can be as toxic as the mould.  

see also fungal infection for other possibilities.

References and further reading

There is a quite wonderful website, easy to understand and use, clearly put together by an enthusiast, called

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