Friday, September 24, 2010

ZOONOSES

Diseases which spread from animals to humans are called zoonotic diseases. Some of these are as follows:


1. Bubonic Plague: 


Caused by the bacteria Yersinia Pestis. Thus plague is normally a problem when humans live in close proximity to rodents. Historically, this has meant rats. Slum populations, with poor hygiene, were thus at greatest risk.


The typical sign of the most common bubonic form of human plague is a swollen and very tender lymph gland, accompanied by pain. The swollen gland is called a bubo. This is usually accompanied by fevers, chills and extreme exhaustion. Natural plague has not evolved significant resistance to antibiotics, and thus remains treatable in most cases.
http://www.zkea.com/archives/archive02005.html
Since plague is zoonotic, eliminating it from the ecosystem is not possible. The bacteria could always lie latent in its animal reservoir even if somehow eliminated from the human population, thus preserving the possibility of future human infections. This contrasts with other strictly-human diseases, such as smallpox. These non-zoonotic diseases can theoretically be driven extinct by vaccines, since the causative pathogen has no refuge outside of human beings.




2. Avian Influenza:






It is caused by the influenza A viruses most frequently found in birds. Flu viruses are rapidly killed by sunlight and tend to dehydrate to death in the breeze.


Like all contagious intestinal and respiratory infections, avian influenza viruses are density-dependent pathogens with a penchant for darkness, dampness, dirt and weakened immune systems – the perfect conditions in which to mutate and proliferate in birds and humans alike. The poultry and eggs one buys at the store came from birds who lived, day in, day out, in excrement, including the excretory ammonia fumes rising from the decomposing droppings in the chicken and turkey houses.These poisonous gases penetrate egg shells (Carlile, 101). They enter the birds’ airways and immune systems, inviting Salmonella,Campylobacter, and avian influenza viruses to colonize, mutate, and spread. 


The droppings themselves contain disease organisms, antibiotic residues, cysts, larvae, and metals such as copper, zinc, and arsenic (UPC [c;d]).

http://www.upc-online.org/poultry_diseases/birdflu.html


Quiz:

1. What  is mad cow disease?

2. What are the symptoms of swine flu?

3.  Who on an average suffers more from depression, man/woman?

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