Anthrax- A Zoonotic Disease of Biblical Proportions

History

Bacillus anthracis is the oldest known disease of grazing animals and is thought to be the cause of two of the plagues mentioned in the Old Testament(diseased livestock and boils).The infectious agent was discovered by Koch in 1877(1^st agent identified using his postulates). The first vaccine is credited to Louis Pasteur in 1877, however it was actually prepared a year earlier by Greenfield in England.

Infectious agent

Bacillus anthracis

-          Forms dominant spores

       - able to survive harsh conditions for decades/centuries

       - lots of evidence they are resistant

              - recovered spores from 200 year old archaeological remains

              - resistant to microwave irradiation at 100C for 30 min

Infection Cycle

Infection

1.      Uptake by inhalation

2.      Spores end up in alveoli of the lungs

3.      Picked up by macrophages

4.      Transported to lymph nodes

5.      Spores germinate in lymph nodes

6.      Multiply and lyse macrophages

7.      Bacilli in bloodstream release lethal factor, edema factor and protective antigen

Here is a link to a good clip about the mechanisms of anthrax:

      http://www.youtube.com/watch?v=7LRGT098lxc&feature=related

3 Forms of Human Disease

Pulmonary

-          Historically 92% mortality rate

-          With early treatment(before toxins released) 45% mortality

-          Initial symptoms mild

          -similar to upper respiratory infection

Gastrointestinal

-          Primary source: eating infected meat

-issue in developing countries

      -  25-60% treatable

            - difficult to identify quickly

Cutaneous

-          Most common source of infection

-          Boil-like lesions, itchy but not very painful

-          Primary source: contact with infected carcasses, contaminated wool/hides

-          Mortality rate(untreated)-20%

Recent Human Anthrax Outbreaks

-          1978-1980- Zimbabwe-

      -10 000 human cases; 151 deaths

-          1979- Sverdlovsk, Russia

       -involved people and livestock

       - traced to release of spores into the air surrounding a biological weapons                                                                                           factory

       - 200 dead?

      -     2001- USA

                   - bioterrorist cases of anthrax in postal service

                   - 22 infected; 5 deaths

      - 2010- Scotland(England and Germany)

                - anthrax-laced heroin

                - 51 cases(known); 14+ dead

Treatment

-          Effective decontamination of: People-antimicrobial soap and water

                                             Wastewater- treat with bleach

                                             Clothing-boil for 30 min.

-          Early antibiotic treatment crucial

-Penicillin, Streptomycin effective at killing bacterium

- Not effective against toxins

Marketing a low cost spay/neuter program

     Spay/neuter is a service that some pet owners simply do not see to be of benefit, so they would not spay/neuter their animal regardless of the price. Therefore, I think that programs promoting spay/neuter must sell the benefits as well as the cost. This will mean the low cost spay/neuter program should heavily market their service by promoting the benefits of spay/neuter. These benefits include reduced risk for some health problems, a reduction in behavioural problems (ie. aggression), elimination of the possibility of a “surprise” litter, and the social benefits (or “warm fuzzies” benefit) of helping to address the problem of animal overpopulation. The marketing/publicity campaigns could also address misconceptions people commonly have regarding the risks or downsides of the spay/neuter procedure. As well some of these marketing campaigns could not only educate pet owners on benefits and costs, they could also attempt to exert social pressure to view spay/neuter as the socially proper thing to do. Many American low cost spay/neuter programs often include television ads, radio spots, billboards, and brochures. Depending on the extent to which these messages are received by the public at large, this can create a positive externality for private veterinarians, encouraging customers to spay/neuter at their practices as well. In addition to a positive effect from marketing, there can be social positive reinforcement, or what has been termed a “bandwagon effect”. It has been found that people tend to spay/neuter more often when they see it as a socially accepted or socially required behaviour for people who have pets. This also may lead low-cost spay/neuter programs to positively affect private-practice spay/neuter procedures.

Not only will there be challenges with convincing lower income households that it is important to spay and neuter their pets but we also have to convince Edmonton area veterinarians that having a program like this will benefit the community and not just take business away from them. As well in our report we are trying to get the EHS to follow our program recommendations. My question would then be how do we change our marketing techniques with each of the three groups, who potentially have different levels of knowledge and different things that they need to get out of the program?

Lions and Tigers and Bears, Oh Cry!

Just this past week authorities in Zanesville, Ohio received a report that 62-year-old Terry Thompson freed about 56 animals, before he took his  own life.  The small town was filled with the dangerous animals including, bears, leopards, monkeys, tigers and wolves.
While police officers tried to save the lives of the animals, apparently the high risk of danger caused them to kill many of them using their pistols before they were able to be tranquilized. I find myself questioning this statement. Did they really do all they could to try and save these animals or was is just more convenient to kill them. All the people in the town were under strict orders to remain indoors and schools were shut down so there was little risk of people getting injured and indeed no one did so why did they not do more to save the animals.Of the 56 animals released 48 ANIMALS WERE KILLED (1-Wolf, 6 black bears, 2-grizzly bears, 9 lions, 8 lionessess, 1 baboon, 3 mountain lions and 18 tigers).  ONLY SIX REMAIN ALIVE and two have not been captured yet. .
I find it absolutely appalling that dozens of beautiful (and some endangered) animals had to be destroyed because of this man’s actions. He had been convicted of animal cruelty in the past so why was he still allowed to keep these (or any animals for that matter) on his property. Would we have to deal with this massive problem in the first place if there had been better controls?

Reports state that the owner was released from jail just three weeks ago after a one year sentence. It seems that this man had broken the law several times including a few instances involving animal cruelty. So my question is why was absolutely NO ONE aware of all the animals that were kept on his property? Who cared for them for that year he was in jail? I get that safety was the issue that drove the sheriff to kill all the animals but this could of been prevented. Those animals could have been rescued and saved during that year the owner was in jail. I find it shameful that there are not better laws that protect our animals! It so easy now to say we had to do it (kill them), that we had no choice. Ohio you had so many choices and in my mind you made the wrong one and to make matters worse now you want to justify your cruel actions by saying you did the public a service.

All of this reminded me once again of an excellent film which I will suggest you take a look at. It’s a documentary by Michael Webber called, “The Elephant in the Living Room” and it examines the complex issue of private ownership of dangerous wild animals.

                                                          

   From beasts we scorn as soulless,
In forest, field and den,
The cry goes up to witness
The soullessness of men.
~M. Frida Hartley

Animals and Society

I think it is very interesting to see the changes in how animals are viewed and treated by humans in today’s society. The first relationship that humans had with animals was primarily a predator-prey relationship. Humans would hunt animals to eat and use for other things such as clothing, tools, etc. Humans eventually domesticated animals that had suitable characteristics for use on their farms. Horses and oxen were used in the field and for transportation, dogs for guarding, cats for pest control. Humans then selectively bred these animals for those purposes. The roles these same animals have today have radically changed however. This can be seen both positively and negatively. Surveys have shown that the majority of households view their pets as part of their family. Anthropomorphizing our animals may not be the best thing. On the one hand animals (especially companion animals) are treated better, generally. They have better living conditions for one. Also animals are thought of as being sentient beings deserving of respect and basic rights. Sometimes this gets taken to the extremes. People forget what their animals were originally bred for. Dogs that were originally bred to work are often left at home all day locked in the house. Then when these animals redirect their pent up energy or their breed-specific behaviours they are punished by their owners. I think that we have in some cases gone too far with treating our pets like family. I think that there is still a difference between a dog and a human and that dressing your dog up in clothes, taking them to a restaurant and allowing them to sleep in your bed are going too far. So many of the designer dogs I see have behaviour problems because they no longer know what it is to be a dog. Our society has very little to worry about in terms of food and shelter that we now have the luxury of treating our animals as humans. But is this okay that some animals live a more luxurious life than many humans do? Not just in developing countries but the homeless people in our own cities. What about the dog who has just inherited millions from their deceased owners while many humans have to choose between food and shelter? Though I am a self- proclaimed animal lover I feel that we have as a (mostly developed) society forgotten that animals are not humans and that though they should have the right to be free from harm and have access to necessary food and shelter, it should not be at the expense of our fellow human beings.

Epidemiology

     Alright so Wiki crash course in what Epidemiology is. Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a society. Major areas of epidemiologic work include outbreak investigation, disease surveillance and screening (medicine), biomonitoring, and comparisons of treatment effects such as in clinical trials.

     So go figure the Greeks were the first to study epidemiology as well. The Greek physician Hippocrates is actually known as the father of epidemiology and is the first person known to have examined the relationships between the occurrence of disease and environmental influence. Apparently he thought up the terms endemic (for diseases usually found in some places but not in others) and epidemic (for disease that are seen at some times but not others). I think that it is astounding that thousands of years ago, people were already trying to figure out what was causing diseases (other than the gods being angry with them).

     So, Epidemiologists try to determine what factors are connected with diseases (risk factors), and what factors may protect people or animals against disease (protective factors). This area of science tries to understand possible causes of contagious diseases like smallpox, typhoid and polio among humans. I find it fascinating however that epidemiological studies can never prove causation. Epidemiology cannot prove that a specific risk factor actually causes the disease being studied, it is only able to show that this risk factor has a correlation with a higher incidence of disease in the population exposed to that risk factor. So how do they know if they have got the right pathogen (in the case of an infectious disease)? I know Koch’s postulates are supposed to help to make this link. For everyone who is unfamiliar Koch’s postulates are as follows:

1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
2. The microorganism must be isolated from a diseased organism and grown in pure culture.
3. The cultured microorganism should cause disease when introduced into a healthy organism.
4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.

These were described quite a while ago and are now updated to look at genes and gene products, however these principles are still used. There are however some major problems with these postulates. Firstly, what about chronic infections, or people who remain asymptomatic? Well you could say to look for antibodies in the blood. However what if they had the disease previously and are now better, but because of memory, they still have antibodies? There is also the problem that some pathogens are unable to be cultured in a lab. Also what do you do in the cases (ie. in the gut or in the mouth) where there are many pathogens? So admittedly there are problems with the postulates but surely there are risks for not following the postulates as well.

One last thing before I finish with this session. I think it is interesting to see that chronic disease is replacing infectious disease as the most important causes of death.