Around 5,000 years ago, humans discovered that they could domesticate animals. So, as it were, they adopted animals like cows, cattle, sheep, dogs and other animals for their benefit. However, scientists now believe that domesticating these animals might have started the process of pathogens (microbes that come from animals) transmitting from animals to humans, and as a result marking the beginning of various infections such as COVID-19. Not just the origin of animal transmitted diseases, the study has answered many more questions regarding the origin of infections and diseases. So, what did the large scale Australian study say? Let us find out:
Large-Scale DNA Study Maps 37,000 Years Of Disease History
Scientists from Curtin University in Australia and Denmark's University of Copenhagen have, in a first study of its kind, analysed 279 DNA samples of human and animal remains that were as old as 37,000 years. From these archeologically obtained carcasses, the scientists then obtained many pathogens present in ancient genetic fragments of bacteria, viruses and parasites. Several of these bugs were also identified as precursors to microbes that still pose a risk to us, such as tapeworms, hepatitis B virus, salmonella and mycobacterium (tuberculosis). Of the 58 genera of these bugs, several were identified as precursors to microbes that still pose a risk to us, which include but are not limited to: tapeworms, the hepatitis B virus, salmonella, and mycobacterium (tuberculosis).
The authors explained "To construct an archaeogenetic spatiotemporal map of human pathogens, we processed shotgun-sequencing data from 1,313 ancient humans, spanning 37,000 years of Eurasian history. We find there is widespread evidence of ancient bacterial, viral and parasite DNA, with 5,486 individual hits on 492 species from 136 genera, and of these hits, 3,384 hits were on known human pathogens, many of which have likely never been observed within ancient human remains."
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Domestication Of Animals Created New Diseases
While studying these ancient pathogens, scientists realised something very interesting. They looked at the timelines and found out that these pathogens started jumping at an unprecedented scale from animals to humans. And, as a result many endemics and pandemic started and disseminated. The domestication of animals such as cows, pigs, sheep and chickens permitted optimal situations for zoonotic pathogens to jump to humans. Much of our most serious diseases – tuberculosis, influenza and measles – probably all started as animal infections. We have more than enough modern examples of zoonotic outbreaks to demonstrate that it's not merely an ancient phenomenon.
Common Diseases Associated With Domesticated Animals
- Salmonellosis: Transmitted through contact with infected animal
- E. coli: Can be found in the intestines of many animals, including cattle and pigs, and can cause diarrhea
- Campylobacteriosis: Can cause diarrhea, abdominal pain, and fever.
- Leptospirosis: Transmitted through contact with urine from infected animals like rats and cattle. Brucellosis: Associated with cattle, sheep, and goats.
Bottom Line
This study not only helps understand our past and the history of diseases in mankind but also is an important discovery in terms of development of future vaccines. By studying how diseases and disease carrying bacteria and viruses evolve, the scientists may be able to understand how current diseases would adapt in the future and create vaccines based on that knowledge.