Question 20. Design a program to eradicate rabies as a human disease, based on your understanding of the virus' life cycle.

This is one of the most specific questions in the exam. The question wants you to design a programme, a strategy (which allows much freedom), but the program you propose must be based on the virus’ life cycle (therefore you MUST learn the rabies cycle). One question arises (and therefore adds to variability in exam answers): Is it even possible to eradicate a disease like rabies with current methods?

BACKGROUND (Textbook Schaechter, 2007, pp. 357-362)
Zoonosis caused by lyssavirus (RNA virus) from infected domesticated (dogs, cats) and wild animals (bats, raccons, jackals). Prevalent in many countries (50,000-100,000 deaths/year), more deaths common in developing countries (90%) where there is less programmes to combat disease. Virtually all people exhibiting symptoms will die (as they weren’t vaccinated), only few notable exceptions in recent times overruled this (see Wikipedia article HERE).

THE RABIES VIRUS LIFE CYCLE
Virus enters from the site of the bite, travelling in the peripheral nervous system (PNS) via nerves to CNS. It travels from the brain to peripheral sites (other organs) eliciting symptoms (virus retroactively travels back and forth brain and organs). Notably, salivary glands in mouth and cheeks will store high concentrations of the virus allowing transmissibility (especially if bitten). Incubation period varies from about 1 month to 3 months, but can be a year or more! (Depends on virulence strain-different locales or even point of infection-worse if face or neck).

SYMPTOMS
Important: Causes acute, progressive, incurable encephalitis (inflamm of the brain caused by infection/allergic reaction)- causes brain damage.
Acute progressive fever, headache, difficulty swallowing + hydrophobia (cannot swallow water to quench thirst), paresthesia (abnormal tingling, nerve damage), muscle spasms, hypersalivation (like rabid dogs), paralysis, mania (confusion, anxiety, etc)

PROGRAMMES

This programme has to tie in to YOUR UNDERSTANDING of the virus’ life cycle.
Methods have to be utilising already present strategies (ie. Cannot say.. we have to design a better vaccine that’s 100% effective before + after infection, that's not a program, that's a wish)

Vaccination of humans, wild and domesticated animals is most effective.
You may decide how far to take this: surely you can’t vaccinate every single living thing in the world, but maybe highly populated areas: suburbs, places of high prevalence. Or maybe people with high risk in contracting disease: kids, vet workers, gardeners, rangers, etc.

Surveillance/Animal control is key in human-populated areas. Ensure wild populations of bats are controlled (various methods to do that… ethically), but use of animal shelters/animal control rangers to isolate rabid stray dogs (euthanasing them, etc). Local leash laws to prevent pets becoming strays.

Education of the community. Advertising, schools-education, brochures to tell people to look for the symptoms (urgent intervention important), stay away from touching wild animals or strays (to prevent getting bitten)

POINTS TO CONSIDER NOW:
1. EACH OF THESE COMPONENTS NEED TO BE TIED BACK TO LIFE CYCLE (how it affects it)…
2. Ian Peak has put forth a rather ideological question, in how do you eradicate rabies as a human disease. My basis, if this were to be on the exam is that it is not possible to eradicate Rabies as a human disease with current methods. The only way is prevention, via vaccination, animal control and education to prevent infection (as you cannot feasibly enact a strategy to destroy all rabid animals, wild or domestic). In relating to stopping disease manifestation with a programme based on the virus life cycle, this is a difficult question. You will always have the possibility of infection as long as there are infected animals present. We can only control it to prevent infection in the first place, or find methods to fix the problem once infected (eg. the induced coma method as shown in Wikipedia).
3. Eventually, it culminates to the thought: What is eradication of a human disease. Strictly speaking, eradication is 'complete destruction', as in no chance of returning. However, this is not possible realistically (unless someone can tell me how), are we content to suggest eradication is like prevalence of Rabies in USA (about 1-3 cases a year, while 50,000-100,000 occur world-wide)...

Good Question, Ian. :S

If you have a differing opinion/additional info, write your own answer or comment below!