Most commonly, immunity: "a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion." (Wikipedia). Immunity is naturally acquired (via exposure or maternally-transferred antibodies in utero) or artificially required through the use of vaccines.
Marek's Disease is a highly contagious viral disease among chickens. It is not transmittable to humans. Chickens with healthy immune systems can combat the virus and even though exposed, they do not have the disease themselves. So, YES, you can eat eggs from chickens who have been exposed to Marek's.
People can be exposed to chemicals on farms, in factories, and even in homes.
People can be exposed to chemicals on farms, in factories, and even in homes.
Yes. MCD can be blood-borne, and is a real concern if you have CJD (Cruetzfeldt-Jakobson Disease, human-equivalent to Mad Cow), so much so that you may not even be allowed to donate blood at all.
Broken teeth are subject to decay. Tooth decay is associated with other health problems such as heart disease and perhaps even cancer. An exposed nerve would be very uncomfortable. See a health clinic about getting your condition remedied.
Dengue Fever
Not a disease per say, the overconsumption of salt is often called the "silent killer".
Possibly. If you were exposed to chlamydia, you should get tested, even if you were on antibiotics at the time.
Yes; even if it weren't registered (which it is), it would be protected by common law.
If by protected class you mean the same as not being able to discriminate against a worker the same as for sex, religion, etc., then no, it is not a protected class.Realistically, in many jobs there would be no discrimination involved in a decision to hire or let someone with rheumatoid arthritis go. If left untreated, and possibly even if treated, RA is a degenerative disease that can deform the hands or feet especially to such a degree as to make it impossible to do some kinds, or even any kind of work.
No, there isn't. But there is a preventative medication one can take while in malaria-infested areas to keep the disease from taking hold even if one would get exposed to it.
No. Bovine spongiform encephalopathy (BSE, the scientific name for mad cow disease) is caused by a misfold protein called a prion. The disease has only ever been identified in cattle and some humans (where the disease is called variant Creutzfeld-Jacobs Disease or vCJD); BSE has never been found in horses. In addition, the BSE prion is transmitted through ingestion of infected central nervous system tissue, not through saliva. The worst possible case would be that you might have been exposed to rabies, but your horse would have died of the disease within a few weeks after you were exposed. Even if this happened, you would have started showing signs of rabies at least 8 years ago and would likely have already died from rabies by now. Long story short, you shouldn't have any concerns about this event - any potential infections would have shown up a long time ago.