Have you ever wondered how a mad dog can become a reason for the death of a human being? You maybe have heard the name of a disease called, which is caused due to the bite of a mad dog. The disease is known as Rabies, which is transmitted to humans with a mad dog’s bite, and was discovered at least centuries ago.
Rabies is not the only disease brought by animals to human society, there are numerous other viral diseases affecting human health caused by animals, and the term used for these diseases is zoonosis.
In medical history, Rudolph Virchow was the first scientist to designate these diseases as a zoonosis in the 19th century. A zoonosis is known to be a disease, transmitted from animals-to-humans, from earlier in medical history.
The concept of animals bringing diseases to human society had affirmed with the visual pieces of evidence and the visualization of the presence of zoonosis was firstly experienced by the medical scientist, in the late the 1600s, when the light microscope was invented by the dynamic Leeuwenhoek.
Now, when it had become possible to see parasites or bacteria, medical science got a lot of help to evaluate and confirmed the connection between a causative agent and the disease, so it facilitated the diagnosis of the exact cause of a disease in human bodies.
How do animals bring diseases to human society?
The relationship between animals and human beings is not an unknown phenomenon. For years, animals are providing several benefits to humans, people interact with them in so many ways during their daily routine, whether they are at home or not.
Animals, not only provide food, livelihood, sport, fiber, or sport, but they also provide companionship to the humans around them, such as pets or domestic animals. There is maybe a few number of world households, who don’t have pet animals, otherwise a huge population across the world is living with their pets. (Franco, 2013 )
So the contact takes place with animals in many ways including in rural or urban settings, while cuddling with your pets at home, outdoor activities with them, enjoying animal exhibits, or during traveling, etc.
Being that much in a relationship with animals, it has bound to happen that animals will be brought diseases with them. They do carry harmful germs, sometimes, even unnoticeable, and become a reason for human illness.
Medical science has given the phenomena of animals’ transmitted diseases a name called zoonotic or zoonosis diseases. These diseases are mainly caused by injurious germs such as bacteria, fungi, parasites, or viruses. These germs are categorized further in several different types, causing illness in humans and fellow animals too, from a range of mild symptoms or illness to sometimes even causing death.
Animals spread these germs in numerous common ways, which mostly being ignored by people around the world. Some of these common ways include direct or indirect connection, foodborne, waterborne, or vector-borne.
Direct contact includes when humans come into contact with any of animals’ body fluids such as blood, saliva, feces, or urine and indirect contact includes coming into touch with the areas, where animals live such as pet habitats, aquariums, plants, or chicken coops. Vector-borne is the type of connection, when a flea, mosquito, or any other insect bite humans.
Drinking polluted water by animals because of their feces or infections is also a type of connection that can cause serious illness. Similarly, drinking or eating contaminated foods, such as undercooked meat or eggs, unpasteurized milk, or raw fruits or veggies which are polluted due to animal feces, fall in the category of indirect human connection with animals, and also become a reason for human illness.
People, who live and work on animal farms, remain in close contact with numerous types of livestock, which is possibly a familiar form of several zoonoses. Similarly, people, who like to have pet animals are at risk of zoonosis, because pets can be the carriers of fleas or ticks that can further move to their families. (Rotter, 1990)
Going down to the history of zoonosis!
The historic data for diseases brought by animals into human society, started from centuries ago when human society had faced countless plagues and extensive epidemics. Plagues are the most devastating human diseases caused by the bacteria transmitted to human society with the bite of a flea. Small rodents, specifically included squirrels, mice, and rats, which have always lived among human beings for centuries, carry the germs of plague.
These plagues had left immeasurable and historic impacts on human society, affecting almost every aspect of their lives including the human population. Other than the presence of plagues, since the beginning of human civilization, there had been some devastating epidemics that had affected the human population in an enormous way.
During the 19th century, Bovine tuberculosis (TB) was almost the first most noticeable disease in medical science, which had considered to be a significant cause of human death at that time. A German microbiologist, Robert Koch first identified the disease in 1882, as an injurious and infectious threat to human civilization.
TB was discovered to be transmitted in human bodies by the Mycobacterium Bovis bacteria, with the help of direct contact with an infected animal or the consumption of unpasteurized dairy products. (Wolfe, 2007)
Until 1907, the disease remained incurable, then French scientist Louis Pasteur developed the process of pasteurization that helped to kill those microorganisms present in milk with the use of heat, and later in 1925, the process of pasteurization was proved to be safe and beneficial.
Other than TB, Rabies was one of the earliest diseases transmitted to humans with the bite of a mad dog, and it has been known since 2000BC.
Georg Gottfried Zinke was the first scientist who demonstrated the fact that rabies was imputable an infectious factor. Then in 1804, the scientist discovered that the disease is transmitted from a rabid dog to a healthy human or even animal. This discovery led the scientist Louis Pasteur to take an interest in 1880, and he soon discovered the first effective rabies vaccine.
After checking its effects on dogs, he treated a young boy Joseph Meister. Louis Pasteur and the infected boy’s physician together treated the boy with the blend of the spinal cord of a rabbit that contained the diminished rabies virus. Then they carried out a regimen of injections as part of the treatment, and then after 3 months, the boy was declared rabies-free and healthy as well.
Zoonotic diseases and their discoveries!
There are numerous diseases brought to human society by animals, some of them with mild effects, but most dangerous for health and the human immunity system. From ancient times, till now, medical science is concerned about the discovery of different existing and emerging diseases caused by the animals’ interactions.
Similarly, with the discovery of multiple diseases, medical science is concerned about developing relevant vaccines to save humanity. Here you go with some of the most devastating zoonosis, that humanity is still struggling with. (Nibert, 2003 )
MRSA (Methicillin-resistant Staphylococcus aureus)
MRSA is a skin disease caused due to a certain type of bacteria that is impenetrable to some particular antibiotics. The disease causes skin infections in humans as well as animals, and the disease can be transmitted to both animals and humans.
It is commonly spread due to direct contact skin-to-skin, so people, who have pet animals are often infected with MRSA through the touching nose or skin, etc. Because of its resistance to antibiotics, the disease is very difficult to cure when a person is infected. So pet owners have to be careful about it.
This disease is a syndrome of pulmonary organs, and it is extremely severe. Hantavirus is caused by inhaling the contaminated air or specifically dust due to deer mice droppings, salvia, or urine. People, who are infected with this disease feel symptoms similar to the flu, and with the worst condition of this disease, people suffer from shortness of breath because their lungs are filled with fluids.
Hantavirus is a fatal disease with cases of the pulmonary syndrome. To save themselves from the disease, people should avoid dust by stirring up rodent nests, and other contaminated material into the air, or droppings. They should follow some rodent control measures and make sure the proper cleaning of rodents to prevent Hantavirus pulmonary syndrome.
Giardiasis disease is caused by some tiny parasites, named Giardia, which can affect the human intestines after the infection. Direct or indirect contact with an infected animal, or even another infected person can cause this disease in another person.
There are various symptoms after the infection, an individual can have including, headache, vomiting, nausea, fever, gas, stomach cramps, and diarrhea. The symptoms can be mild or severe according to the intensity of the infections.
The parasites of Giardia have been discovered to be in cats and dogs, some wild animals, and some ruminants’ animals like cows or goats.
Bird Flu or Avian Influenza is one of the most severe diseases caused by mostly wild water birds. The viruses of this disease mostly occur in water birds naturally and can infect not only humans but also animals, other birds, or poultry.
If there is no direct interaction with infected animals or birds, due to these viruses people rarely get infected by influenza viruses, but on the other hand, if there is a direct or close interaction with the infected animals, poultry, and birds, there are maximum chances of infection.
The viruses of Bird Flu are continuously changing, and some particular changes help the virus of influenza to spread conveniently within the human population, and there is always a danger of pandemic or large breakout of flu.
How to prevent zoonosis?
Preventing the environment and human population from several zoonotic diseases is not impossible rather there are medically proven measures and certain precautions, people adopt to stay safe and healthy.
Firstly, across the globe, a continuously increasing trend of having pets at home, in bedrooms, and cuddling with pets, touching or kissing the, or even sleeping with them, need a lot of effort to provide yourself with proper self-care.
People with pets, people working in farmhouses, poultry businesses, zoos, or other areas where they have to interact with multiple types of animals, vet clinics, and many other places, have to take intense care of their personal hygiene.
For personal hygiene, the first and foremost step to be taken is washing hands after every interaction with animals, putting on masks in those areas, and avoiding drinking or eating there. Then there are multiple measures that should be taken for your safety.
Medical science has developed numerous proven precautionary measures to protect the human population from zoonotic diseases, still, there are numerous outbreaks and pandemics, human civilization has experienced over the year.
With the invention of vaccines and with the passage of time various zoonosis are curable and people can be recovered still there is diseases like rabies, which don’t have any effective treatment after the infection is established in the human body, and it is still causing deaths in various corners of the world, specifically rural areas, or the areas of the world with less privileged, unaware, or uneducated people.
When it comes to people who are at risk due to the diseases brought by animals, there is no such exception. Anyone, including young-to-old, men or women, and healthy or unhealthy people can get sick or infected through an animal bite, an insect bite, or whatever.
So the medically proven precautionary measures are necessary to be taken by all the people. However, there is a group of people, whose intensity of infection or sickness can be increased as compared to a healthy individual.
This group of people mostly includes infants or toddlers, older people, pregnant women, and people with low immunity, so the other family members should help them to stay prevented from these viral infections because they can get severely sick or even die due to some worst viral infections caused by animals.
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- Wolfe. (2007). Origins of major human infectious diseases. Nature, .