[SOUND] [MUSIC] [SOUND] [MUSIC] It's remarkable actually that some of the most contagious diseases can even be carried within human respiratory tract. Foot and mouth disease virus for instance which Doctor Miller's going to be talking about, that can be carried in a human respiratory tract. And you can leave a farm with foot and mouth disease, change all of your clothes, move to another farm. And because the virus is not infecting you but it's present in your respiratory tract you can breathe it out onto another farm. So, that means that we have to design a biosecurity or biocontainment policy, we have to really understand the biology of those infectious agents as well. We have to know how that pathogen causes infection, so there's a really important science underlying the biology of transmission of agents. So we need to know how those agents are transmitted, we need to know what the incubation period is as well. Because very often there might be animals that are contagious that don't show advert chemical signs. For instance if you have influenza you might be contagious before you show signs of sneezing and show signs of coughing. So we have to know at what stage of the disease is the animal contagious. That's true at the beginning of the disease and that's true at the end of disease. When does an infected animal become non contagious? When can we take it from its isolation or its quarantine facilities and place it back within the normal population? We need to know about reservoirs are there diseased reservoirs, is there a carrier state. Some infectious agents hide in the body and they hide from the immune system and don't produce any clinical disease at all in the animal. There's one disease that's very common in our ruminant population in the United States and the United Kingdom and it's called Johne's disease. And it's produced by an agent called Mycobacterium paratuberculosis, and those animals pick up that disease when they're young calves. They can get it when they're older but they're much more susceptible when they're young calves. And it's transmitted fecal orally, it's transmitted by the feces of an infected animal, and then a non infected animal has to ingest those feces. So if you think about a young calf, when's that most likely to happen? It's most likely to happen when they are seeking around their mother, trying to nurse the teats or sniff around on the legs. So if you have an infected mother, and a non infected calf, the most important period of infection is in that newborn period in the first month or first two months of life. That agent is also transmitted in the colostrum and in the milk, so even the newborn calf can pick up that agent in the milk. So to design biosecurity or biocontainment policies and procedures against Johne's disease, Mycobacterium paratuberculosis. We have to understand that the dam, the mother, is the source of it very often, and the important period of susceptibility is for the newborn calf. So how would we do that? What we do is maybe as soon as the calf is born is to take it away from its mother. We can feed it milk from a non infected animal or take the milk, or colostrum, from the mother and pasteurize it to try and kill the bacteria. So there are lots of procedures that we can do, but we need to know the biology of transmission and where the risk factors are. And very often the cow might not be showing any clinical disease at all. The cow might not have diarrhea, might not have weight loss, so has no signs of that infection in the early stages but still be a source of infection for the newborn calf. So understand the biology of the infection is really, really important, understanding the incubation period is very, very important. Understanding that the mothers in that situation are the reservoirs, is a very, very important element of biosecurity and designing good biosecurity and biocontainment procedures. Another mode of transmission, so we've talked about animal to animal contact. We've talked about the people being a source of transmission, movement of utensils, shared feeding equipment, that could be a source of transmission of disease between different animals. But interestingly, there are some diseases that are spread by fomites, they're spread by even other animals. So when we talk about biosecurity we want to think about, are other animals spreading disease? For instance, rodents, rats and mice can spread disease on poultry farms, so rodent control becomes a very, very important element of that. Wild birds can introduce disease into a poultry flock so the control of access to wild birds for instance with avian influenza is an important part of our disease control. So stopping the movement of other animals onto premises by using perimeter fences is very, very important in biosecurity procedures. Particularly in some of those more contagious, those more contagious infectious diseases. You'll see when we have a national outbreak that there can be a regional control of movement. So during foot and mouth outbreaks in the United Kingdom, we had areas in which no animals could move in and out of those areas. So the government would, as it would draw a line around the whole region, a whole set of farms that might be a county. That might be several counties, that might be a whole state in the United States, no animals could move in and out of there. And a lot of our legislation, a lot of government protocols are designed to stop the movement of contagious disease between different states. Doctor Miller will be talking about that more near the end. And what we like to do in some ways is to prevent disease and we've talked about that many times and we'll keep on because it's such an important concept. We'd much rather prevent disease and infectious disease than we would treat infectious disease. So what we've done we've adopted a HACCP approach, we'll talk a little bit more about that in week six. But the HACCP approach is an approach that's used to manage risk. Now the HACCP approach which means hazard analysis and critical control point isn't just confined to infectious disease. It's used for the prevention of many risky activities, health and safety for instance. But we can use this same approach by looking at a premises, looking at the risk of a particular disease on a particular group of animals. So to do that, first of all, we need to do a risk analysis, we need to look at all of the potential parts of the system which form actually a risk, for contraction of that disease. As we mentioned earlier the idea of a mother and a calf, do we need to separate that calf, because that's the risk period. So once we've done our risk analysis and risk assessment, so there we know when the critical control points are. Then the next stages are risk management, is then going in and implementing, or designing procedures and processes which control the potential for disease transmission at those critical control points. But it only works, if we put it into action, so, the last stage of our HACCP approach to bar security is risk communication. So making sure that our personnel are well trained and they appreciate and actually have ownership to the control of the disease management that's on that particular premises. So as we've mentioned week after week the people are the most important part of our production system for disease control. And for the health and well being of the animals. [MUSIC]
