Human and animal health are closely linked, and many diseases are common. As our world becomes more evolved and interconnected, the proximity between wild animals and humans is shrinking, increasing the threat of disease transmission. At the same time, humans rely on animals as a source of food.
The emergence of new diseases is an unfortunate result of these trends. According to the World Health Organization, most of the newly discovered human diseases (about 75%) originated in animals in the last three decades. Scientists refer to these types of diseases as “zoonotic. “
As humans face the growing threat of zoonotic diseases, it is critical to understand how reversing our reliance on meat, dairy, and other animal products can help have a definitive effect on our health and the health of the planet, while ensuring a better life. for humans. animals.
What is a zoonotic disease?
A zoonotic disease is a disease that is transmitted from an animal population to humans. According to the Centers for Disease Control and Prevention, zoonotic diseases are produced through germs such as bacteria, viruses, parasites, and fungi. Many other types of zoonotic diseases cause human diseases. Ailments that range in severity from mild to life-threatening.
According to the World Health Organization, it is estimated that six out of ten internationally known infectious diseases have spread between animals and humans, and zoonotic diseases are becoming more prevalent.
What are the causes of zoonoses?
Humans around the world live in close proximity to domestic and wild animals, which is largely due to our food system’s reliance on commercial animal agriculture. As we face the demanding situations posed by this “unsustainable agricultural intensification,” i. e. , “[destroying] plant buffers that protect humans from viruses circulating among wildlife,” according to the United Nations; Fitness experts say it’s very important to understand how zoonotic diseases can spread.
Direct contact
Diseases can be transmitted from animals to humans who come into direct contact with them by touching an inflamed animal, for example, or by being bitten by an animal. Zoonotic diseases are transmitted by direct contact with an inflamed animal’s physical fluids, such as urine, blood, saliva, feces, or mucus.
Indirect contact
Humans can also become inflamed in an animal’s habitat or dwelling. For example, zoonotic diseases can be transmitted to a human while cleaning an aquarium or chicken coop or when handling a pet’s food and water. On commercial poultry farms, birds live in miserable situations, with the ground flooded with urine and feces, creating ideal situations for the animals to get sick.
Vector transmission
In epidemiology, a “vector” refers to insects, arachnids, and other small organisms that transmit infection from one host to another.
An inflamed tick, for example, can attach itself to a human and transmit Lymes disease. This is also why mosquito bites can cause serious diseases such as Zika virus, malaria, and yellow fever.
Foodborne
Foodborne illness, or food poisoning, can be caused by eating raw or undercooked animal products. Eggs and poultry are among the most common sources of food poisoning. Salmonella and campylobacter, from raw eggs and birds, are common zoonotic diseases. Chickens are among the most widely farmed land animals in the United States and the world. The U. S. raised more than nine billion poultry for meat in 2020 alone.
Water-based
Drinking water infected with harmful bacteria can cause illness in humans. For example, lakes, rivers, and streams infected with animal manure can contain high levels of E bacteria. coli, which is found in the feces of warm-blooded animals.
E. coli contamination is one explanation for why factory farms can have devastating effects on nearby water bodies. If ingested by humans, infected water can cause mild abdominal discomfort, serious health problems, and even death.
How are zoonotic diseases transmitted between animals and humans?
Zoonotic diseases can spread in many ways between animals and humans. However, public health researchers have uncovered a common thread among many of the main culprits of zoonotic diseases. That is, factory farming and the ingestion of animals around the world greatly increase the dangers. That can cause the next primary outbreak.
Agriculture and livestock
By a conservative estimate, the agriculture industry has been blamed for about a portion of all new zoonotic diseases since 1940, according to a November 2022 article in Science Advances. Epidemiologists believe this percentage is likely higher. Livestock farming contributes to creating ideal situations for the spread of diseases: animals that are overly pressured, sometimes living in miserable situations and crammed into confined spaces, come into contact with human workers.
Intensive agriculture creates the best typhoon for the spread of zoonotic diseases.
Wildlife Trade
In addition to livestock farming, the legal and illegal industry (i. e. , the global industry of non-domestic animals and plants) is one of the main motivating forces for zoonotic diseases.
A 2021 study published in Current Biology found that more than 25% of industry mammals are to blame for 75% of all known zoonotic diseases, given that the complex procedure of transporting those animals produces “more than a billion direct and oblique contacts between Array animals and domestic animals,” the study’s lead author, K. Nagaraju Shivaprakash, concluded that “the industry. . . It is [possibly] a vital element in the global spread of zoonotic diseases and emerging infectious diseases.
Animal captivity
Keeping animals in captivity and exploiting them for human entertainment raises many ethical and ethical issues. Animals in captivity also pose public health risks. Petting zoos and other animal exhibits where humans may touch captive animals are of particular concern. According to 2007 figures provided through the CDC, 25 zoonotic disease outbreaks were linked to animal exposure.
Insect Vectors
There are more than a billion insects for every human being on Earth. While these little creatures are essential to our survival, some can also lead to deadly diseases.
Ticks, fleas, and female mosquitoes (male mosquitoes bite) can cause a variety of diseases, most of which are now treatable. However, one of the worst pandemics in history, the Black Death, has been attributed to inflamed fleas.
Deforestation and habitat destruction
Deforestation and habitat destruction, caused primarily by the agricultural industry, pose serious environmental risks. When wild animals see their habitat destroyed, they still have no choice but to uproot themselves and look for a new home. During those trips, you’re more likely to “bump into” other animals, expanding the chances that a once-contained disease will spread to another population.
Climate change
Because of the reasons for habitat destruction, scientists say climate replacement is already expanding the chances that humans will face more common zoonotic pandemics. The likelihood of excessive outbreaks would possibly increase as much as threefold in the coming decades,” warns a 2021 article in the Proceedings of the National Academy of Sciences.
Livestock farming contributes more to greenhouse fuel emissions than the shipping sector.
The resulting excessive heat at the equator, caused by global warming, is causing many species to head toward the poles in search of more hospitable climates. This has led previously distant animal species to travel wonderful distances, most likely expanding their possibilities of contact with humans and other animals and potentially spreading disease.
Polluted & Water
Food or water infected with a bacteria, virus or parasite causes tens of millions of cases of food poisoning a year and more than 1,000 deaths in the United States alone, according to the CDC.
Norovirus is the leading cause of death from foodborne illness in the United States. After that, salmonella, C. perfringens, and campylobacter are the other deadliest pathogens. “Campylobacteriosis is the most reported gastrointestinal disease” in the European Union, with more than 129,000 cases. reported in 2021, an increase of 5. 6% compared to 2020.
The European Center for Disease Prevention and Control found that food and meat accounted for 20 to 30% of human infection cases.
How are zoonoses classified?
Fitness experts classify zoonotic diseases according to their root cause. In other words, the pathogen of the disease can simply be a bacterium, a virus, or something else.
Bacterial zoonoses
Bacterial zoonoses are diseases caused by single-celled microorganisms discovered almost on Earth and inside the human body. Most bacteria are harmless, even useful, and relatively few cause disease.
Viral zoonoses
Viral zoonotic diseases are diseases caused by viruses, which are infectious microbes composed of DNA or RNA surrounded by a “protein envelope. “They can infect humans, other animals, plants, fungi, and bacteria.
Parasitic zoonoses
Parasitic zoonotic diseases are diseases caused by parasites that attach to or discover themselves in the host’s body. Parasitic diseases can be transmitted from animals to humans through the ingestion of raw or undercooked meat or by ingesting food or water infected with the feces of an inflamed animal. .
Fungal zoonoses
Fungal zoonoses are diseases caused by fungi, spore-producing organisms, such as molds, yeasts, and fungi. Fungi can cause topical infections on a person’s body (such as rashes and brittle nails) or on the body (such as infections of the lungs or bloodstream). ).
Rickettsia zoonoses
Rickettsia zoonoses are diseases caused by a type of bacteria that can only live inside the cells of other organisms. Rickettsia infections are regularly transmitted to humans through the bites of vectors such as ticks, lice, fleas, and mites.
Chlamydia zoonoses
Zoonotic chlamydia diseases are diseases caused by a family circle of a bacterium called chlamydia, one of the most common infectious agents affecting humans. A type of bacteria is transmitted to humans as a sexually transmitted infection and is sometimes colloquially referred to as chlamydia. This version, however, affects domestic birds and can be transmitted to humans when they care for their birds or clean their cages.
Mycoplasma zoonoses
Mycoplasma zoonoses are diseases caused by an atypical circle of relatives of bacteria that are harder to kill with antibiotics. Mycoplasma pneumoniae can infect the human respiratory formula (a mild form of pneumonia is known as “walking pneumonia”) and is transmitted through tiny droplets from coughing and sneezing. There have also been reports that this type of bacteria is transmitted from animals to humans.
Protozoan zoonoses
Protozoal zoonoses are diseases caused by protozoan parasites and transmitted from puppies to their owners. Many humans are protected against such diseases thanks to a strong immune system. However, sitters of puppies who are immunocompromised are at a much higher risk.
Non-viral cell-free pathogenic zoonoses
Non-viral acellular pathogenic zoonoses refer to diseases caused by highly or poorly understood pathogens, such as the prion, a misfolded protein. The prion is thought to be the cause of neurological disorders such as mad cow disease and similar diseases affecting the human brain.
Examples of zoonotic diseases
Avian influenza
Avian influenza, or avian influenza, is a viral disease that primarily affects wild and domestic waterfowl. As of April 10, 2024, more than 85 million poultry have been affected by an outbreak of avian influenza, most of which were raised laying hens. in cramped cages. Although in rare cases it has inflamed humans, given the severe outbreak in wild and domestic bird populations, public fitness experts are concerned about other possible occasions of contagion in the near future.
Due to the huge number of birds we raise in factories, we especially increase this risk. Keeping birds indoors, in dirty situations and often under pressure is the ideal environment for bird flu to develop.
salmonellosis
Salmonellosis is caused by infection with salmonella bacteria, which live in the digestive tracts of birds and other animals. Humans are at risk of contracting an infection if they practice smart handwashing behavior and consume raw eggs, unpasteurized dairy products, or undercooked meat.
Psittacosis
Humans can get psittacosis from inflamed bird pups, such as parrots and cockatiels, or from domestic poultry, such as chickens and turkeys. The disease is usually mild and relatively brief in humans.
Rage
Rabies is a viral disease that can affect any mammal, but it is most closely related to bats, raccoons, skunks, foxes, and dogs. Rabies is often transmitted to humans through the bite of an inflamed animal. The infection has effects on the central system. It is nervous formula and is fatal at most once symptoms are present.
Cat scratch disease
Cat scratch disease is a bacterial infection. It can be transmitted to humans when a cat licks an open wound or scratches a user deep enough to break the skin. The infection can cause redness around the wound site, swollen glands, and flu-like symptoms. Although symptoms are usually mild, in rare cases the infection can be serious if it spreads to other organs.
Malaria
Malaria is a disease caused by a parasite that is transmitted to humans through mosquito bites. If left untreated, malaria can be fatal, especially in children under the age of five. The disease is not unusual in countries near the equator, especially in sub-Saharan Africa and Oceania.
Virus del Zika
Mosquito bites are the most common cause of Zika virus. However, it can also be transmitted from a pregnant mother to her child or through sexual contact. Symptoms of the virus come with a mild rash and illness. However, it can cause serious illness. Congenital disorders in newborns.
Lyme disease
Lyme disease is the most common vector-borne zoonosis in the United States. It is caused by the bites of inflamed blacklegged ticks. Although easy to treat, if left untreated, Lyme disease can lead to prolonged pain, stiffness, and swelling, as well as reminiscence disorders and difficulty concentrating.
Bubonic plague
Responsible for the most notorious pandemic in history, known as the Black Death or Black Death, the bubonic plague still erupts in some cases around the world. However, outbreaks of this zoonotic bacteria-borne disease can be controlled with antibiotics.
Swine flu
Also known as H1N1 flu, swine flu is caused by a flu virus that began infecting humans in 2009, causing a pandemic in humans, pigs, and birds. Pigs with swine flu can amplify symptoms ranging from fever, coughing, and sneezing to depression. and lack of appetite. Humans can have health problems from being around pigs on farms or county fairs.
COVID-19
Scientists agree that the COVID-19 pandemic originated in a non-human animal. However, there is still no definitive conclusion on the origin. According to the WHO, the leading theory is that the COVID-19 virus originated in bats and spread to humans. some other animal.
Who is into zoonotic diseases?
As we have learned from the profound effects of COVID-19, no one is immune to a zoonotic disease. However, there are a number of risk points that can put some people at higher risk of infection than others.
According to the CDC, children under the age of five, adults over the age of 65, those with weakened immune systems, and pregnant women are at increased risk for severe illness due to zoonotic diseases.
What Can You Do To Yourself With Zoonotic Diseases?
Animals are all around us, whether they’re buzzing around us outside, roaming our gardens, or even living inside our homes. This means that there is a threat that a bacteria, virus, or other pathogen could pass from an inflamed animal to one of us. .
The CDC has put together a handy list of tactics against preventable zoonotic diseases:
Wash your hands after touching animals or animal products. Soap and running water for 20 seconds are one of the most effective tactics to prevent the spread of germs. If soap and water are not available, the most productive solution is to use a hand sanitizer that is at least 60% alcohol.
Avoid tick, flea, and mosquito bites outdoors by wearing insect repellent and long-sleeved shirts and heeding CDC fitness warnings in your area.
If you have pets in your home, learn about the diseases that usually suffer from them and how to keep them healthy.
Be it from animal exhibits and petting zoos.
However, the rise of factory farms in the 20th century has reshaped our food formula into one in which thousands of animals are crammed into dense, unsanitary housing, creating situations ripe for disease. While it is imperative to take individual precautions to avoid contracting zoonotic diseases, the risk remains high unless we jointly replace our dating with non-human animals.
Prevention of zoonotic diseases worldwide
Public fitness experts agree that the world wants to tackle the leading cause of emerging zoonotic diseases: animal consumption. A 2022 study paper published in the journal Science Advances explains that changing the way we raise animals for meat isn’t enough to stop the acceleration of those diseases.
Intensive agriculture is the main cause of deforestation, which promotes the spread of disease on a global scale. To further increase productivity, animals are raised in more extensive systems, but this procedure involves confining the animals (and their feces) together in confined spaces. Not only is it inhumane, but in such gigantic quantities and under such stress, it also promotes the spread of disease.
Research shows that slowing the spread of zoonotic diseases will require reducing global reliance on animal products as a food source while accelerating forest conservation efforts around the world.
Putting an end to extensive livestock farming
Much remains to be done to end extensive livestock farming and make the world a safer position for humans and non-human animals.
We will need to hold corporations and elected officials accountable for how their movements advance the welfare of nonhuman animals and public health. Governments will need to avoid subsidizing livestock farming and instead support more sustainable farming practices.
Greater awareness is also needed to teach other people about animal atrocities, extensive agriculture, and highlight the overall environmental and health benefits of moving to a plant-based diet.
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This article produced through Earth | Food | Life, commissioned by the Independent Media Institute.