Rabies MCQ

Rabies MCQ

Q1. Which of the following is true for rabies?

A. Rabies is prevented by pre-exposre prophylaxis
B. The death rate is highest in the elderly
C. All the vaccines can be used intradermally
D. Deaths have occurred post transplant

Answer and interpretation

D, there have been rare cases including post corneal transplant from a patient that was unknown to have died from rabies passing on the disease.
Pre-exposure prophylaxis only primes the immune system it will not prevent the disease completely hence the need for post-exposure prophylaxis
The death rate is highest in children with 40% under the age of 15 years.
Only Rabipur and Verolab have been approved by the WHO for this route


Q2. The risk of rabies is in?

A. Dogs more than bats, worldwide.
B. Greater in children than adults
C. Dogs in Asia more than Europe
D all the above

Answer and interpretation

D, all the above. Dogs are responsible for 99% of cases and rabies affects mainly the poor rural communities in Asia and Africa, although it can occur in any country in the world. In fact, if you were in America then the predominant cause of rabies would be from he bat.


Q3. Rabies Immunoglobulin?

A. Is only manufactured as a human immunoglobulin
B. At least half the dose should be infiltrated around the wound
C. Can only be given within 1 week of a bite
D. If you are really concerned can be given IV in very high risk cases

Answer and interpretation

B, half the dose is usually infiltrated into the wound and the other half is given intramuscularly at another site. 

There is also horse immunoglobulin and this is more widely available but has a higher risk or serum sickness. Typical recommendations when giving post-exposure prophylaxis state that immunoglobulin can be given within 7 days of starting the vaccine. However, if you had a new possible case present even up to a year later then you would give the vaccine and the immunoglobulin if recommended. The immunoglobulin should always be given IM.


Q4. Which of the following is true regarding intradermal rabies vaccine versus intramuscular routes?

A. ID gives lower antibody titres using the same time schedule (days 0, 7, and 28) as IM administered vaccines
B. An ID schedule is less effective in the long term than an IM one
C. ID vaccine is less effective in post-exposure prophylaxis than IM vaccine
D. Five injections of ID vaccine are required (days 0, 3, 7, 14 and 28) compared to two IM injections  (days 0 and 3) in post-exposure cases where the traveller has had a full pre-exposure prophylaxis by either the ID or the IM routes.

Answer and interpretation

A. There are lower antibody titres but long term outcomes are not affected. WHO recommends day 0 and 3 for post exposure prophylaxis either ID or IM in the fully-immunised, an alternative regimen would be the “4-site” intradermal. This consists of 4 injections of 0.1ml equally distributed over left and right deltoids, thigh or supra scapular areas during a single visit.


Q5. The rabies vaccine?

A. Is a live vaccine
B. Is cell cultured, freeze dried and reconstituted prior to administration
C. Is a polysaccharide vaccine derived from culture on human diploid cells
D. Can not be given to breast feeding mothers

Answer and interpretation

B. It is an inactivated vaccine, usually from the Wistar rabies strain. The only polysaccharide vaccines are pneumococcal, meingicocal and salmonella Typhi. The vaccine is safe in children, pregnancy and breast feeding.


Q6. Which of the following is false regarding the rabies vaccine?

A. The rabies vaccine should never be given intravenously
B. The dosage is the same for children as it is for adults
C. Human diploid cell vaccine can lead to ulceration if given intradermally
D. The vaccine is safe to give with live vaccines

Answer and interpretation

C, It does not cause ulceration, nor do the other vaccines.


Q7. A traveller comes to your clinic after getting two doses of a vaccine 6 months ago and next week is travelling to an endemic area for rabies. What should you do?

A. Start the scheduling again and get him to cancel his trip
B. Give one dose of vaccine and assume he has good cover
C. Order the same vaccine he used and give him one extra dose
D. Assume he already has enough cover

Answer and interpretation

B, Lengthening the intervals between vaccine is okay, shortening them is not. Answer B is the safest and most pragmatic. 


Q8. The clinical disease?

A. The incubation period is proportional to the time the virus takes to travel from the inoculation site to the brain and/or spinal cord
B. The incubation period is normally 3-6 months
C. The autonomic nervous system is usually spared
D. The clinical disease mostly begins as a flu-like illness

Answer and interpretation

A. The illness usually begins within 2 weeks  to 2 months of the initial exposure but, exceptionally, may not appear for a year (rarely, 19 years after the initial incident).

Rabies usually starts fairly abruptly with fever, anxiety, insomnia and behavioural changes, notably agitation. Paraesthaesia, pain and intense itching at the site of the bite are also features. Two-thirds of the cases go on to exhibit hydrophobia and delirium (furious rabies). One-third goes on to ‘paralytic’ rabies with an ascending sensori-motor neuropathy, cranial nerve palsies and marked personality/behavioural changes.

The ANS is not spared. Profuse salivation (‘froth at the mouth’) and excessive sweating mark both the furious and paralytic forms.

Rabies virus travels in nerve axons to the brain and spinal cord. This means that the quickest deaths will occur in bites to the head or neck with large inoculums of virus. Such a scenario is more likely in children than in adults. Early institution of treatment including injection of rabies immune globulin into the site of the bite is essential.

Intensive care and the administration of a cocktail of antiviral drugs have been reported to have saved some patients with bat-rabies. However any form of clinical rabies is a virtual death sentence. Recovery is extraordinarily rare.


Q9. Rabies virus?

A. Is a flavivirus
B. Is transmitted by aerosolised secretions
C. Is a reverse-zoonosis
D. Is more likely to cause paralytic rabies in dogs than in other non-human animals

Answer and interpretation

B. Rabies is a viral zoonosis that is transmissible to humans. The virus can be readily transmitted by direct inoculation or by sometimes by aerosol inhalation. Speleologists (cave explorers) are especially liable to pick up the virus from infected bats in this way. Bat rabies is regularly reported from the US and Australia. Rabies virus is a rhabdovirus, belonging to the genus lyssavirus. Paralytic rabies is far more likely to appear in cats than in dogs.


Q10. The best public health measure is?

A. Kill all stray dogs
B. Vaccinate all dogs
C. Add the rabies vaccine to the countries immunisation schedule
D. Capture all animals that bite to observe them for 15 days to guide medical management

Answer and interpretation

B. Mass vaccination programs have proven the most cost effective. By vaccinating 70% of dogs actually breaks the transmission cycle.


References

Dr Neil Long BMBS FACEM FRCEM FRCPC. Emergency Physician at Burnaby Hospital in Vancouver. Loves the misery of alpine climbing and working in austere environments. Supporter of FOAMed, toxicology, tropical medicine, sim and ultrasound

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