Rabies is endemic to over 150 countries, and according to the World Health Organization, 99% of all transmissions to humans are from dogs, potentially bringing into question the animal’s status as the ‘man’s best friend’.
In Europe, southern Africa, and parts of North America, most cases are acquired from wild carnivores; mongooses, and vampire bats in Latin America and the Caribbean. In more recent years, humans have acquired rabies from inhalation of aerosols in bat caves, ingestion of dogs and cats for food, ticks, cart-scratches, and inadvertent transplantation of corneas or internal organs from infected donors.
In recognition of World Rabies Day, we have asked our co-founder, Dr. Stephen Berger, for his take on the disease. He didn’t hold back with the assessment!
“Rabies, from an evolutionary standpoint, is a truly “stupid” disease. Most animals with Rabies virus infection become paralyzed and die – thereby preventing the survival and reproduction of the virus itself. Ebola and Smallpox, albeit highly contagious, are also “stupid” in this respect,” said Dr. Berger, highlighting an interesting point.
When a disease limits its access to new hosts, how does it survive and continue to spread?
How long before it’s too late?
Virus transmission takes place via exposure to infected saliva, not necessarily a bite – although bites are the most common means of transmission. The virus is very active in moist conditions but quickly becomes non-infectious when dried or exposed to direct sunlight.
In dogs, the virus incubates for between 2 weeks to 4 months before the animal can transmit the disease.
In human cases, the incubation period can be as short as a few days or take as long as a few months for the disease to become active and symptoms to show. In rare cases, Rabies has appeared as long as five years following an animal bite. Once symptoms appear, the case-fatality rate is virtually 100%. As of 2014, only 13 cases of human survival from rabies had been documented.
Two forms of Rabies
The disease has two recognized forms – Furious and Paralytic, also known as ‘dumb Rabies’. In the furious form, dogs (or humans) froth at the mouth and display extreme hyperactivity. Patients often develop spasms when exposed to water – thus the term “hydrophobia.” In some cases, a similar response will follow fanning the patient – “aerophobia.”
While Furious Rabies is most familiar to the lay public (thanks to the cinema and TV) the Paralytic form often predominates among dogs. This type causes a slow progression from difficulty swallowing to full-body paralysis and eventually, death.
Rabies is 100% vaccine-preventable
When compared to diseases such as Tuberculosis, where symptoms such as coughing actively support transmission through the projection of infectious material into the air, Rabies would seem easier to control, especially when effective preventative and therapeutic vaccines and immune-globulins are available.
The disease was recorded as far back as 556 BC, in China, and a viable vaccine has existed since 1885. The World Health Organization (WHO) considers the disease to be one of the Neglected Tropical Diseases, in part due to the under-usage of effective vaccination, which works even after the virus has entered the body. A lesser-known adjunct to therapy is vitally important, but not as well-known to the public. Thorough cleansing of a wound using soap and water has been shown to reduce the incidence of Rabies by 50% following the bite of a rabid animal!
Sadly, despite the fact that 29 million people receive the vaccine every year, thousands still die from the disease. 95% of deaths occur in Asia and Africa, with children under the age of 15 making up 40% of all cases.
Stray dogs present a significant problem in countries such as India, Namibia, Angola, Mozambique, and Kenya, where annual disease rates exceed 0.2 per 100,000 population.
WHO leads a collective “United Against Rabies” campaign to drive progress towards zero human deaths from dog-mediated Rabies by 2030.
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Want to learn more about Rabies? Check out Rabies: Global Status ebook for the latest epidemiological information.