Impact of microorganisms on human, animal and plant health

 

Impact of microorganisms on human, animal and plant health

Microorganisms are ubiquitous and they have a huge influence on us and our environment. Microorganisms play a dual role in the health of humans, animals, and plants. Their impact on human, animal and plant health can be both beneficial and harmful, depending on the type of microorganism and the conditions of the host which they interact with. 

Beneficial Impacts on Human Health

Microbiota and Gut Health:

The human gut is associated with trillions of microorganisms, including bacteria, viruses, fungi, etc and is collectively termed as the gut microbiota.

These microorganisms play a crucial role in digestion, nutrient absorption, and the synthesis of essential vitamins like vitamin K and B vitamins.

They help in maintaining a healthy immune system by preventing the growth of harmful pathogens through competitive inhibition.

Immune System Modulation:

Microorganisms help in the development and regulation of the immune system.

Probiotics are "live microbial supplement which beneficially affects the host animal by improving its intestinal microbial balance".  Probiotics can boost the immune system and are used in preventing and treating various gastrointestinal disorders.

Biotechnological Applications:

Microorganisms are used in the production of antibiotics, such as Penicillin derived from the fungus Penicillium.

Microorganisms are used in the development of vaccines, production of insulin, therapeutic proteins, enzymes, Bioactive Compounds which are used as medicine to treat life style diseases, cancer etc.

Harmful Impacts on Human Health

Infectious Diseases:

Pathogenic microorganisms, including bacteria, viruses, fungi, and protozoa, are causative agents of a wide range of infectious diseases, such as common cold, gastrointestinal infections, tuberculosis, AIDS, COVID-19, etc.  Pathogenic microorganisms invade human tissues, multiply, and cause damage.

Over and misappropriate of antibiotics have led to the emergence of antibiotic-resistant bacteria which has made infections harder to treat.

Sometimes food is spoiled by the growth of microorganisms.  Microorganisms may cause Foodborne infections and intoxications.  Food infection or foodborne illness occurs when a person consumes food that contain harmful bacteria, viruses, or parasites. These microorganisms cause nausea, vomiting, abdominal pain, diarrhea, etc and may be even led to death.  Examples are infection by Salmonella, E. coli, Campylobacter, Norovirus, Hepatitis A, Rotavirus. Food intoxication or food poisoning occurs when a person eats food that contain toxins produced by certain bacteria. The toxins produced by these bacteria, such as Staphylococcus aureus and Clostridium botulinum cause food intoxication.

Beneficial Impacts on Animal Health

Symbiotic Relationships:

Microorganisms form symbiotic relationships with animals. Ruminants like cows depend on their gut bacteria to help digest cellulose which is a major component of their diet.  In insects like termites, protozoa and bacteria in their gut help in the digestion of cellulose present in wood.

Animals also have a microbiome which plays a vital role in digestion, immune system function, and protecting against pathogenic microorganisms.  Probiotics are also used in veterinary medicine to improve gut health, enhance immunity, and prevent diseases in animals.

Harmful Impacts on Animal Health

Zoonotic Diseases:

Microorganisms cause infectious diseases in animals.  Some microorganisms that infect animals can be transmitted to humans also and such diseases are termed as zoonotic diseases. Examples are Salmonella from poultry and rabies virus from dogs.

Animals are susceptible to various diseases caused by microorganisms, such as Foot-and-Mouth Disease caused by virus, Bovine Tuberculosis caused by Mycobacterium bovis, etc.  These diseases can cause severe economic losses in agriculture and animal populations.

In animals also, overuse of antibiotics in veterinary medicine has led to the development of resistant strains of bacteria, and these pose a challenge in treating infections in animals.

Beneficial Impacts on Plant Health

Nitrogen Fixation - Certain bacteria, such as Rhizobium, form symbiotic relationships with leguminous plants, fixing atmospheric nitrogen which is crucial for plant growth and soil fertility.  Some free-living bacteria like Azotobacter, Azospirillum, etc also contribute to nitrogen fixation in the soil.

Biocontrol Agents -Some microorganisms act as natural biocontrol agents, protecting plants from diseases caused by pathogens and insect pests. Trichoderma, Bacillus thuringiensis, Baculovirus, etc. 

Plant Growth Promotion - Plant Growth-Promoting Rhizobacteria (PGPR) and Mycorrhiza enhance plant growth through the production of plant hormones, solubilization of nutrients and enhancing root development.

Harmful Impacts on Plant Health

Numerous bacteria, fungi, viruses, and nematodes cause plant diseases, leading to reduced crop yields and quality. Examples are bacterial wilt caused by Xanthomonas or Psaeudomonas, Powdery mildew caused by fungi, potato blight caused by Phytophthora infestans, tobacco mosaic virus. Fungi, such as Aspergillus and Fusarium, produce mycotoxins that can contaminate crops like corn, peanuts, and wheat. These toxins are harmful to both humans and animals when ingested.