This week’s NTD topic might sound a little more familiar than the other diseases in this series. When we think about rabies in the United States, the “typical” picture includes a racoon or bat, foaming at the mouth, that is ready to attack at a moment’s notice. What we probably are not thinking about is the global reality, where domesticated dogs cause more than 50,000 deaths per year by transmitting an infectious virus to their caretakers. Rabies is a virus that spreads through the saliva of infected animals. Human rabies cases have been reported on all continents, except Antarctica, and in 150 countries globally [1]. In the United States, it is most commonly associated with exposure to wild animals including bats, skunks, foxes and raccoons [2]. Elsewhere, domestic dogs are the most common reservoir, accounting for 95% of human deaths due to rabies [3].
Rabies is contracted by being bitten, or when handling an infected animal [4]. Most human transmissions globally come from domestic dogs, due to their close proximity in the home as well as with wildlife. However, in the US, the CDC states that more cats than dogs are reported being rabid [4]. The CDC also suggests that if 70% of the 500 million dogs globally were vaccinated, then human deaths from rabies could be eliminated [4]. The primary symptoms of rabies include fever, rash and headache lasting two to 10 days [5]. As the disease progresses, symptoms include anxiety, confusion, agitation, cerebral dysfunction, delirium, abnormal behavior, hallucinations and insomnia [5]. If medical attention is sought immediately after exposure, disease is preventable. However, once clinical signs develop, the disease is predominately fatal [5, 6].
Estimating the impact of rabies globally is difficult because the areas that are most impacted by the disease have little resources to conduct surveillance of rabies and have few diagnostic facilities, so it is difficult to draw an accurate picture of its impact [7]. However, we do know that more than 15 million people worldwide receive post-bite prophylaxis each year, and combined with the number of reported deaths each year, a better image can be created [6]. Human cases of dog-transmitted rabies are disproportionately higher in rural regions of developing countries, accounting for 80% of all rabies-related deaths [3]. According to the World Health Organization, rabies is completely preventable and treatable through animal reservoir vaccinations, but, in the regions most impacted, there is no government infrastructure and public health policy to effectively administer them [3].
In May of 2018, the CDC developed a new rapid test that can diagnose rabies in animals faster than current methods [8]. This test would allow for veterinarians and doctors to know if an animal has rabies sooner, which would lead to faster, more informed decisions on human and animal treatment or prophylaxis. Current treatment for rabies involves receiving post-exposure prophylaxis over the course of weeks, which can cost thousands of dollars [8]. This test could prove whether or not a person was exposed to rabies sooner, avoiding the financial and physical burden of receiving the treatment. This would especially be helpful in areas of the world where access to healthcare is limited. Combined with efforts for dog vaccinations, the global burden of rabies could be greatly reduced.
In the United States, people are lucky enough to have resources to effectively treat and manage any rabies outbreak that occurs in animals and humans. If there is a human death due to rabies, of which there has been less than five a year since 1990, it is because a person was unaware of their exposure and did not seek medical attention until severe symptoms appeared [9]. Yet in some regions of the developing world, rabies is a known risk, but limited access to healthcare and the cost of treatment prevent those exposed from receiving the care they need. Rabies prevention begins with animal control. The Global Alliance for Rabies Control, WHO, World Organisation for Animal Health and the Food and Agriculture Organization of the United Nations have united in plans to vaccinate pets for rabies. As part of their collaboration, they plan to target regions where rabies transmission is highest. Dog-mediated transmission of rabies is projected to be eliminated by 2030 through the utilitization of a strategic plan involving political, socio-cultural, technological and organizational teamwork in order to save tens of thousands of lives a year [10].
Sources:
[1] http://www.who.int/rabies/epidemiology/en/
[2] https://www.mayoclinic.org/diseases-conditions/rabies/symptoms-causes/syc-20351821
[3] http://www.who.int/rabies/about/en/
[4] https://www.cdc.gov/features/rabies/index.html
[5] https://www.cdc.gov/rabies/symptoms/index.html
[6] http://www.who.int/rabies/control/en/
[7] https://www.cdc.gov/rabies/location/world/index.html
[8] http://outbreaknewstoday.com/rabies-cdc-develops-new-rapid-test-lead-fewer-shots-90944/
[9] https://www.cdc.gov/rabies/location/usa/index.html
