Firstly, Hepatitis A and Typhoid can be avoided by watching what you eat and drink and by taking care over your personal hygiene habits. If treated, Typhoid is rarely fatal. Hep. A is untreatable with medication but other than in those aged over 60 or so, is also rarely fatal.

Hepatitis B is not prevalent in Central/South America, is spread by invasive contact with blood or body fluids. So don't share needles and use a condom with the local lads/lasses. I'd be more worried about STD's in general though.

Rabies; invariably fatal, but when was the last time you got bitten by a dog, monkey whatever? It's very likely that locals will take care of any "loco" animals before you meet them. It's not really an issue, as I see it.

Malaria, Yellow Fever and Dengue are human diseases spread by bites from some mosquitos, during or shortly after the rainy season. Proof of Yellow Fever immunisation is necessary for travel to Brasil and therefore unavoidable, should you intend to go there. However, prevention of mosquito bites is the first line of defence. Use of appropriately treated nets, sprays, electric coils, cintronella incense and perhaps even garlic, have their place. Making sure you are protected during dusk is the most important thing.

Dengue has no prophylaxis and the treatment consists of fluids and anti-febriles.

You can be bitten once and contract these diseases, you can be bitten many times and not.

As far as I am aware, the extremely serious stains of Cerebral Malaria are not found in the Americas.

With regard to Malaria, you are only really at risk when others in the area have the disease. That's hard to know when you are travelling rapidly and so is choosing the correct prophylaxis. Prophylaxis is not a guarantee of protection and an alternative is to hold back your medication for treatment in the event that you contract the disease.

There are only some parts of Central/South America where Malaria is an issue, so you need to consider your routes. Some areas of the coast and the Amazonas are where you are going to potentially encounter problems. Above 800 metres you will not encounter problems. Problem is; if you take the correct prophylaxis and rely on it, you are going to need to keep taking the medication regardless of your location.

Should you decide to use it, in South American affected areas, (North), the prophylaxis/treatment is:

Atovaquone/Proguanil, Doxycycline, or Mefloquine.

In Central America, Ecuador and Bolivia the prophylaxis/treatment is: Chloroquine/Proguanil.

We have discussed this here before, but let's not forget that there are potential side-effects and damage associated with this medication.

Personally, I prefer to have the treatment available, take precautions, regulate my lifestyle...and see what happens.

Just my view.

__________________
How much does a man live, after all?
Does he live a thousand days, or one only?
For a week, or several centuries?
How long does a man spend dying?
What does it mean to say “forever”? - Pablo Neruda