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Questions and Answers
What condition must be met to maintain a stable (non-growing) rate of an infection in a population?
What condition must be met to maintain a stable (non-growing) rate of an infection in a population?
Why is the R0 of rabies in humans considered to be zero?
Why is the R0 of rabies in humans considered to be zero?
Which animal is NOT listed as a reservoir for rabies in Canada?
Which animal is NOT listed as a reservoir for rabies in Canada?
What was a common misconception among some rabies victims in the U.S. in 2021?
What was a common misconception among some rabies victims in the U.S. in 2021?
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Who was the first recorded case of rabies in Canada?
Who was the first recorded case of rabies in Canada?
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Which continent does not report any cases of rabies transmission according to the provided information?
Which continent does not report any cases of rabies transmission according to the provided information?
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What is the primary source of human rabies cases worldwide?
What is the primary source of human rabies cases worldwide?
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Which statement regarding rabies virus's characteristics is true?
Which statement regarding rabies virus's characteristics is true?
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What is the usual time frame for the rabies virus to travel from the peripheral nervous system to the brain?
What is the usual time frame for the rabies virus to travel from the peripheral nervous system to the brain?
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In which regions does approximately 99% of human rabies deaths occur?
In which regions does approximately 99% of human rabies deaths occur?
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What contributes to the poor control of dog rabies in some countries?
What contributes to the poor control of dog rabies in some countries?
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Which prevention method for rabies is described in the writings of Columella?
Which prevention method for rabies is described in the writings of Columella?
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What is a common consequence of rabies infection once clinical symptoms appear?
What is a common consequence of rabies infection once clinical symptoms appear?
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What was the significance of Pasteur's observation of old bacterial cultures in chickens?
What was the significance of Pasteur's observation of old bacterial cultures in chickens?
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What does the rabies vaccine protocol include post-exposure for individuals bitten by a rabid animal?
What does the rabies vaccine protocol include post-exposure for individuals bitten by a rabid animal?
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Why was the rabies vaccine developed from the spinal cord of rabies-infected rabbits?
Why was the rabies vaccine developed from the spinal cord of rabies-infected rabbits?
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What does an R0 value of less than 1 indicate about a disease?
What does an R0 value of less than 1 indicate about a disease?
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Who was Joseph Meister and what was his significance in rabies vaccine history?
Who was Joseph Meister and what was his significance in rabies vaccine history?
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What does the term 'postexposure prophylaxis' (PEP) refer to in the context of rabies treatment?
What does the term 'postexposure prophylaxis' (PEP) refer to in the context of rabies treatment?
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What role does human rabies immune globulin (HRIG) play in rabies treatment?
What role does human rabies immune globulin (HRIG) play in rabies treatment?
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What was the purpose of progressively using more virulent samples in the rabies vaccine development?
What was the purpose of progressively using more virulent samples in the rabies vaccine development?
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What percentage of human rabies cases are attributed to dog bites?
What percentage of human rabies cases are attributed to dog bites?
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Which animal is most associated with rabies cases in humans in regions where dogs are well controlled?
Which animal is most associated with rabies cases in humans in regions where dogs are well controlled?
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What was the preventive measure taken by shepherds as described by Columella?
What was the preventive measure taken by shepherds as described by Columella?
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Which region records approximately 99% of human rabies deaths?
Which region records approximately 99% of human rabies deaths?
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What characteristic of the rabies virus makes it environmentally unstable?
What characteristic of the rabies virus makes it environmentally unstable?
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How long can the rabies virus take to spread from the peripheral nervous system to the brain?
How long can the rabies virus take to spread from the peripheral nervous system to the brain?
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Who is attributed with the early understanding of rabies and its effect on dogs?
Who is attributed with the early understanding of rabies and its effect on dogs?
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What is the fate of human rabies infection typically once clinical symptoms appear?
What is the fate of human rabies infection typically once clinical symptoms appear?
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What characteristic of rabies in humans classifies them as a dead-end host?
What characteristic of rabies in humans classifies them as a dead-end host?
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Which animal is NOT identified as a rabies virus reservoir in Canada?
Which animal is NOT identified as a rabies virus reservoir in Canada?
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In the context of rabies deaths in 2021 in the U.S., what factor contributed to the fatalities among the unvaccinated individuals?
In the context of rabies deaths in 2021 in the U.S., what factor contributed to the fatalities among the unvaccinated individuals?
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What was the significance of Charles Lennox, 4th Duke of Richmond, in relation to rabies in Canada?
What was the significance of Charles Lennox, 4th Duke of Richmond, in relation to rabies in Canada?
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What implication does an R0 value greater than 1 have for an infection in a population?
What implication does an R0 value greater than 1 have for an infection in a population?
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What was a key observation made by Pasteur regarding old bacterial cultures in chickens?
What was a key observation made by Pasteur regarding old bacterial cultures in chickens?
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What was the method used by Pasteur to develop the first rabies vaccine?
What was the method used by Pasteur to develop the first rabies vaccine?
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What characterizes the postexposure prophylaxis (PEP) vaccination protocol following a rabies exposure?
What characterizes the postexposure prophylaxis (PEP) vaccination protocol following a rabies exposure?
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What was the outcome for Joseph Meister after receiving the rabies vaccine?
What was the outcome for Joseph Meister after receiving the rabies vaccine?
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What is the estimated number of deaths worldwide due to rabies in the absence of postexposure prophylaxis (PEP)?
What is the estimated number of deaths worldwide due to rabies in the absence of postexposure prophylaxis (PEP)?
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What role does human rabies immune globulin (HRIG) play in the treatment of rabies?
What role does human rabies immune globulin (HRIG) play in the treatment of rabies?
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What does an R0 value of less than 1 indicate about a disease?
What does an R0 value of less than 1 indicate about a disease?
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In what year was the first rabies vaccine developed by Pasteur?
In what year was the first rabies vaccine developed by Pasteur?
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Study Notes
Rabies
- Rabies is a deadly zoonotic disease, responsible for approximately 60,000 deaths worldwide annually.
- The majority of rabies deaths occur in children in developing countries.
- Dog bites are responsible for 95% of human rabies cases.
- Almost all human rabies deaths occur in Africa and Asia, where dog rabies is poorly controlled.
- Effective tools exist to eradicate rabies.
- The Eshnunna Code (2300 BC) held owners of rabid dogs responsible for containing their animals.
- Babylonian king, Adadapla-iddina (1068-1047 BC) constructed a temple to the goddess Gula, a healer and protector from rabies.
- Aristotle observed that rabies infected dogs became irritable and spread the disease through bites.
- Columella (60 AD) recommended tail-cropping as a preventative measure for rabies.
Rabies Transmission and Spread
- Rabies is spread primarily by rabid dogs.
- The disease is found on all continents except Antarctica.
- Asia, Africa, and India experience approximately 59,000 human rabies deaths annually.
- Europe and the Americas have few human rabies deaths due to dog vaccination and the primary source of infection being wildlife (bats, foxes, skunks, raccoons).
The Rabies Virus
- The rabies virus is an RNA virus belonging to the Rhabdoviridae family.
- Its genome consists of 12 kb negative-sense RNA.
- Species-specific variants exist, such as bat, skunk, and fox rabies.
- The virus is environmentally labile and is inactivated by heat (50°C for 15 minutes), sunlight, and desiccation.
- Rabies virus travels from the peripheral nervous system to the brain within 3-12 weeks.
- The virus replicates rapidly in the brain, subsequently spreading to salivary glands and saliva.
- Clinical symptoms appear after the virus reaches the salivary glands, leading to death within 1 week.
- Treatment must be administered before clinical signs develop.
Rabies Control
- Detecting rabies cases is particularly challenging due to long incubation periods and the difficulty in detecting clinical rabies.
Pasteur's Rabies Vaccine
- Louis Pasteur developed the first rabies vaccine using attenuated strains of the virus.
- Pasteur's initial work involved attenuating chicken cholera bacteria.
- He observed that older bacterial cultures were less virulent, protecting chickens from the disease.
- His rabies vaccine involved passing the virus through rabbits, resulting in attenuated but still virulent strains.
- He further attenuated the virus by drying infected rabbit spinal cords, creating a series of decreasingly virulent samples.
- This series of samples was used for canine vaccination.
Joseph Meister and the First Human Rabies Vaccine
- Joseph Meister, a young boy who was bitten by a rabid dog, became the first human to be treated with Pasteur's rabies vaccine.
- He received 13 inoculations over 3 weeks, with increasing virulence levels.
- He did not develop rabies, demonstrating the vaccine's effectiveness post-infection.
Later Rabies Vaccines and Protocols
- In 1911, the Philadelphia drug company H.K. Mulford introduced a rabies vaccine protocol that could be administered by physicians without prior experience.
- The protocol involved 25 injections over 18 days, using increasing doses of slightly more virulent samples.
Rabies Vaccination
- Dog vaccination is crucial to prevent rabies infection.
- Humans can receive post-bite rabies vaccinations and a dose of human rabies immune globulin (HRIG) to provide immediate antibodies.
Postexposure Prophylaxis (PEP)
- PEP includes a rabies vaccine administered on the day of exposure, followed by additional vaccinations on days 3, 7, and 14.
- This protocol is vital in preventing rabies after animal bites.
- The WHO estimates an estimated 3 million rabies deaths would occur annually without PEP, demonstrating its effectiveness.
Rabies R0
- R0 (basic reproduction number) represents the number of new infections caused by one infected individual.
- An R0 of less than 1 indicates that the disease will die out on its own.
- An R0 of 1 suggests a stable disease rate, while an R0 greater than 1 indicates an epidemic.
- The R0 of rabies in dogs is greater than 1 due to their social nature and interaction through teeth.
Rabies in Humans
- Humans are considered a dead-end host for rabies, meaning the R0 in humans is effectively zero.
- Rabies cannot be significantly decreased by only treating humans.
First Rabies Case in Canada
- Records indicate that the first rabies case in Canada was in 1819, affecting Charles Lennox, the 4th Duke of Richmond.
- The duke died in August 1819, and a cairn was erected in 1926 on the location of his death along Old Richmond Road.
Rabies Reservoirs in Canada
- Rabies virus reservoirs in Canada include arctic foxes, red foxes, skunks, raccoons, and bats.
Recent Rabies Cases
- In 2021, there were five rabies deaths recorded in the United States.
- Four of the victims were not vaccinated.
- The fifth victim was bitten by a rabid dog while traveling in the Philippines and later died in New York.
Rabies in Canada
- The text mentions rabies in Canada for the year 2024, indicating the continued presence of the disease.
Rabies
- One of the most deadly zoonotics
- ~60,000 deaths world-wide, majority are children in developing countries
- 95% of human cases are due to dog bites
- ~99% of human deaths occur in Africa and Asia, dog rabies is poorly controlled
- Tools to eradicate rabies are available
History
- Mesopotamians (2300 BC) recognized rabies, owners of rabid dogs were responsible for containment
- Babylonian king (1068-1047 BC) constructed a temple to Gula, a healer and protector from rabies
- Aristotle (384-322 BC) recognized rabies in dogs and that it could be transmitted to other animals
- Columella (60 AD) described cutting puppy tails as a preventative measure against rabies
Transmission and Spread
- Primarily transmitted through bites from infected mammals, mainly dogs
- Most common in Asia, Africa, and India
- Few human deaths in Europe and Americas
- Vaccination efforts have been successful in preventing dog rabies in these regions
- Rabies in Europe and America is primarily transmitted through wildlife (bats, foxes, skunks, raccoons) as opposed to domestic animals
- All continents except Antarctica are affected by rabies
Rabies Virus
- RNA virus in the Rhabdoviridae family
- 12 kb negative sense RNA genome
- Species-specific variants (e.g., bat, skunk, fox)
- Labile in the environment, can be inactivated by heat, sunlight, and desiccation
Rabies Progression
- Virus travels from the peripheral nervous system to the brain, taking 3-12 weeks
- Rapid replication in the brain
- Centrifugal spread to salivary glands and saliva
- Clinical symptoms usually develop within a week of reaching the brain, often leading to death
- Treatment is most effective prior to clinical signs
- Little to no transmission during the preclinical phase
Challenges in Control
- Long incubation periods make detection difficult
- Clinical rabies is tricky to diagnose
Rabies Vaccine Development
- Louis Pasteur developed the first rabies vaccine using a method of attenuating the rabies virus in rabbits, starting with mild strains and gradually increasing the virulence
- The first successful vaccine was used to treat Joseph Meister, who was bitten by a rabid dog
- The first rabies vaccine for humans was developed in 1911 and required 25 injections over 19 days
- Vaccination has been crucial in controlling rabies in dogs and humans
Postexposure Prophylaxis (PEP)
- PEP includes administration of human rabies immune globulin (HRIG) and multiple doses of the rabies vaccine
- Rabies PEP includes a dose of HRIG on the day of exposure
- Followed by a vaccination series on days 3, 7 , and 14
- PEP has significantly reduced the number of rabies deaths worldwide
- Approximately 29 million doses of PEP are administered worldwide annually
- It is estimated that 3 million deaths would occur each year without PEP
Rabies R0
- R0 >1 means a single infected individual will cause more than one new infection, leading to an epidemic
- R0 < 1 means the disease will die out on its own
- Rabies in dogs has a R0 of >1 due to their social behaviour and tendency to interact with their teeth
- Humans are a dead-end host because rabies cannot be transmitted between humans
- Reducing rabies in humans requires controlling the disease in animal reservoirs, not just treating human cases
Rabies in Canada
- The first documented case in Canada was in 1819, Charles Lennox, 4th Duke of Richmond, died of rabies after being bitten.
- Canada has various wild animal reservoirs: Arctic foxes, red foxes, skunks, raccoons, and bats
- In 2024, there was a significant increase of reported rabies cases in Canada
- In 2021, there were 5 rabies deaths in the U.S.
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Description
Explore the critical information about rabies, a lethal zoonotic disease. Learn about its transmission, historical context, and the global efforts to control this disease. This quiz provides insights into the impact of dog bites and the importance of preventive measures.
