Year : 2017 | Volume
: 7 | Issue : 2 | Page : 21--22
Impact of Plant Diseases on Human Health
Abdullah M Al-Sadi
Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khod, Oman
Abdullah M Al-Sadi
Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O. Box-34, Al-Khod 123
|How to cite this article:|
Al-Sadi AM. Impact of Plant Diseases on Human Health.Int J Nutr Pharmacol Neurol Dis 2017;7:21-22
|How to cite this URL:|
Al-Sadi AM. Impact of Plant Diseases on Human Health. Int J Nutr Pharmacol Neurol Dis [serial online] 2017 [cited 2019 Jun 17 ];7:21-22
Available from: http://www.ijnpnd.com/text.asp?2017/7/2/21/205287
Plant diseases have always been a challenge to plant growth and crop production in several parts of the world. Plant diseases can affect plants by interfering with several processes such as the absorbance and translocation of water and nutrients, photosynthesis, flower and fruit development, plant growth and development and cell division and enlargement. Plant diseases can be caused by different types of fungi, bacteria, phytoplasma, viruses, viroids, nematodes and other agents. The severity of diseases caused by these pathogens varies from mild symptoms to decline of the infected plants, depending on the aggressiveness of the pathogen, host resistance, environmental conditions, duration of infection and other factors. Plant disease symptoms vary with the infecting pathogen and the infected part and can include leaf spots, leaf blights, root rots, fruit rots, fruit spots, wilt, dieback and decline.
Although infection of plants by pathogens can have serious consequences on plant health, human health can be affected by one of the several ways. Viruses, bacteria and fungi that infect plants do not usually cause infection in humans. However, a study reported that Pepper mild mottle virus may react with the immune system of humans and induce a clinical symptom, but the study did not provide a clear evidence on the pathogenic role of this plant virus in humans. Despite the question about the possible direct effect of plant pathogens on humans, several plant pathogens can affect humans by reducing the available food or by contaminating human food with toxic compounds. Human health can also be affected by bacterial species living in agricultural soils and used as biocontrol agents for plant diseases.
Plant diseases are well known to reduce the food available to humans by ultimately interfering with crop yields. This can result in inadequate food to humans or lead to starvation and death in the worst cases. For example, late blight disease of potato, which is caused by Phytophthora infestans, destroyed potatoes which were the main crop in Ireland during 1845–1850. This resulted in the Great Famine (or Great Hunger), where about one million people died and another million emigrated to Canada, the USA and other countries. Rust is another example of a disease that threatens several crops, including wheat which is known to be one of the three most important crops in the world. Plant diseases continue to be a challenge to crop production in different countries, not only through reductions of crop yields, but indeed through reduction of fruit quality and nutritional value.
One of the most common ways by which plant diseases can affect humans is through the secretion of toxic metabolites ’mycotoxins’ by fungi infecting plant products. Although the fungi producing these mycotoxins infect plants but not humans, these mycotoxins can have direct effects on humans and animals, resulting in diseases and death. Examples of fungal species producing mycotoxins include Aspergillus flavus, Fusarium spp. and Penicillium spp. There are several groups of mycotoxins under which several types are included. Aflatoxins are one of the most common and serious groups (types = B1, B2, G1 and G2), which are produced by some Aspergillus species. Aflatoxin B1 is one of the most serious mycotoxins, because it is lethal at high doses and is carcinogenic to humans at low doses and can result in reduced liver function, vomiting and abdominal pain. Annual deaths in some parts of Africa due to the effect of aflatoxin have been reported to reach 250,000 annually. Mycotoxins can be found in several products, especially peanuts, pistachios and maize. Infection of these products by mycotoxin-producing fungi can occur in the field or during storage. In addition, mycotoxins can be consumed indirectly by humans through the consumption of meat from animals fed on food contaminated with mycotoxins.
Ergot is also a disease of several cereals including bread wheat. It is caused by some fungi belonging to the Claviceps genus. Consumption of bread produced from contaminated flour can result in ergotism disease in humans. Ergotism has been reported to result in death, loss of peripheral sensation or hallucinations.
Although most plant pathogens do not infect humans, it is advised to avoid consuming rotted or mouldy fruits and vegetables or food contaminated by toxin-producing fungi. Removing diseased parts of fruits may help reduce pathogen inoculum and rotted fruit parts. However, it may not ensure that all contamination has been excluded as some fungi and their toxins can diffuse into symptom-less parts of fruits. Although cooking may result in the decomposition of some mycotoxins, some mycotoxins are not destroyed by high heat. The effects of some mycotoxins can be reduced through the addition of some mycotoxin-binding agents or through deactivation.
More research is required on the direct effects of plant pathogens and diseases on humans. Special attention should be given to mycotoxin-producing fungi and their presence in human food. Efforts should be directed towards avoiding plant disease epidemics similar to the late blight disease of potatoes in Ireland through food diversification and the development of effective plant disease management strategies. Awareness of community about the ways by which plant diseases can affect human health is also important.
Thanks are due to Sultan Qaboos University and Oman Animal and Plant Genetic Resources Center for the support of the studies on fungi (EG/AGR/CROP/16/01).
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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