{"id":57202,"date":"2020-06-16T23:00:19","date_gmt":"2020-06-16T23:00:19","guid":{"rendered":"https:\/\/www.zinpro.com\/what-are-viruses-and-how-do-they-impact-animal-production\/"},"modified":"2024-09-20T12:11:36","modified_gmt":"2024-09-20T17:11:36","slug":"what-are-viruses-and-how-do-they-impact-animal-production","status":"publish","type":"post","link":"https:\/\/www.zinpro.com\/en_na\/resource-center\/blog\/what-are-viruses-and-how-do-they-impact-animal-production\/","title":{"rendered":"What Are Viruses and How Do They Impact Animal Production?"},"content":{"rendered":"

Dr. Marco Rebollo, DVM also contributed to this post.<\/strong><\/p>\n\n\n\n

Part 1 of a 4-part series on viruses in animal production<\/em>.<\/p>\n\n\n\n

Viruses are having a major impact on animal\nproduction all around the world. Viruses can affect just about any tissue in\nthe body, including the intestines, lungs, liver, kidneys, uterus, ovaries, the\nspinal cord, the brain and even the skin. <\/p>\n\n\n\n

When viruses infect animals, it can affect\ngrowth, performance, reproduction and even lead to death. Controlling harmful\nviruses, like influenza, infectious bronchitis virus, BRSV and others is key to\nproducing healthy, high-performing animals. First, we need to understand what\nviruses are and how they work to affect animals. <\/p>\n\n\n\n

A virus is a submicroscopic infectious agent\nthat replicates only inside the living cells of an organism and lacks the\nability to survive or reproduce for a long period of time outside of a host.\nViruses are present in plants, animals, insects and the environment all around\nthe world and can cause problems in the normal function and structure of\nanimals and their bodies. <\/p>\n\n\n\n

The control of viruses, using vaccines,\nenhanced biosecurity and antiviral medications, among other strategies, as well\nas adequate zinc nutrition has helped extend animal life expectancies, improve\nproductivity, performance and reproduction. <\/p>\n\n\n\n

How Do Animal Viruses Work? <\/h2>\n\n\n\n

Viruses are made of either a single or double\nstrand of nucleic acids and are classified as either RNA or DNA with\nprotections in the form of either a capsule or an envelope. Viruses can enter\nthe body through ingestion, inhalation of air, across the skin, or through the\nreproductive tract at the time of breeding. <\/p>\n\n\n\n

Once an animal becomes infected with a virus,\nthe virus can inject its genetic material into the healthy cells of an animal.\nIt is then able to make the cells work to replicate the virus into many\nviruses, which can then be shed and further spread to other animals or, in some\nrare cases, to the humans caring for them. <\/p>\n\n\n\n

While viruses have been recognized for many\nyears as an etiological agent of disease, there are some viruses that do not\ncause diseases right away. They will live dormant in the cells of an animal\nuntil a stress event occurs. This could be transportation stress, heat stress,\ncold stress or stress from high stocking densities. Stress could cause a virus\nto come back out of dormancy and start to produce clinical disease. <\/p>\n\n\n\n

While viruses can sometimes lead to death,\nmost viral infections don\u2019t directly lead to the demise of an animal. Instead,\nthey initiate a depression in the immune system, which then allows bacterial\npathogens to come into the animal and lead to death from a bacterial infection.\nThis is very common in feedlot cattle.<\/p>\n\n\n\n

Where Do Coronaviruses Fit In?<\/h2>\n\n\n\n

Basically,\nall species have a coronavirus \u2014 respiratory or enteric \u2014 that can infect them.\nCoronaviruses are quite common in animals. For example, cattle have a bovine\ncoronavirus that causes respiratory disease. In poultry, infectious bronchitis\nvirus (IBV) is classified as a coronavirus. Porcine\nepidemic diarrhea (PED) is a coronavirus that can\nimpact young pigs. Then our companion animals \u2014 cats and dogs \u2014 can be infected\nwith feline infectious peritonitis and certain respiratory conditions. Those\ncoronaviruses affecting farm animals are different from those affecting humans\n(SARS-CoV2, SARS-CoV and MERS-CoV). It is highly unlikely that they will infect\nor cause disease in humans or that those from humans will infect farm animals. <\/p>\n\n\n\n

Challenges with Animal Viruses<\/h2>\n\n\n\n

The big challenge is that viruses are\nultramicroscopic, which means that they are under 300 nanometers in size. This\nmeans that viruses can easily become aerosolized. They can float in the air and\nspread very easily, especially inside enclosed spaces. So, the higher the\nstocking density of animals, the easier a virus can spread between animals. <\/p>\n\n\n\n

For example, an outbreak of foot-and-mouth\ndisease, which can affect many cloven hoof animal species, between Britain and\nFrance is thought to have spread by the virus being carried\non the air across the English Channel.<\/p>\n\n\n\n

While a virus can travel on its own through\nthe air, there are other ways that a virus can travel by surviving in a host\u2019s\nbody. For example, Encephalitis viruses (western and eastern) in horses can be\ncarried, maintained and spread by mosquitos and birds. Additionally, bats are\nknown to carry and spread viruses, such as rabies, influenza and coronaviruses\nwithout showing clinical symptoms. <\/p>\n\n\n\n

Another\nchallenge that animal producers face when it comes to viruses is the ability of\nthe viruses to mutate. As animals build an immunity to a certain virus, the\nvirus can mutate and change. This means that the virus can become more\ninfectious or less infectious, more virulent or less virulent or can start\ninfecting other species, including humans in some cases.  This is always a big fear with avian and\nswine influenza viruses.<\/p>\n\n\n\n

When\na virus starts adapting to a new species, it can become very pathogenic. So, in\nthe time it jumps to different individuals of the new species, it starts to\nadapt. It takes time before that virus establishes a friendly relationship with\nthe new host. That’s why we see massive outbreaks and are going through this current\npandemic, which is a virus that is adapting.<\/p>\n\n\n\n

Virus Management in Animals<\/h2>\n\n\n\n

Around the world we have built animal\nproduction systems that are conducive to increasing the spread of viral infections,\nlargely due to high stocking densities. As a result, animal producers can\nreduce the spread of viruses by reducing stocking density. Many poultry systems\nare already doing this as the industry transitions to antibiotic-free\nproduction practices, which naturally has resulted in placing fewer birds in\neach house. <\/p>\n\n\n\n

Other ways to reduce the spread of viruses is\nusing antiviral medications and vaccines. Many viruses, including influenza,\nNewcastle disease and Marek\u2019s disease, have effective vaccines readily\navailable for animal producers. Antiviral medications, however, are oftentimes\ncost prohibitive while vaccines take time, research and technology to produce.\nTherefore, the best way to prevent a virus from infecting your animals is to\nenhance your physical biosecurity to keep a virus as far away from animals as\npossible. <\/p>\n\n\n\n

Enhancing your physical biosecurity involves: <\/p>\n\n\n\n