~Written by Theresa Majeski (Contact: theresa.majeski@gmail.com; Twitter: @theresamajeski)
Rabies is a neglected viral disease that is found on all continents except Antarctica and is endemic in 150 countries and territories. While rabies can be found almost everywhere, 95% of cases occur in Africa and Asia. Rabies is almost always fatal following the onset of symptoms. However, rabies is vaccine-preventable and can be eliminated. The World Health Organization (WHO) in conjunction with the Food and Agriculture Organization of the United Nations (FAO), the World Organization for Animal Health (OIE), and the Global Alliance for Rabies Control is raising awareness about rabies. September 28th is World Rabies Day and this year’s theme is “End Rabies Together”.
Figure 1. Worldwide map of rabies indicating level of risk by country, 2011. Courtesy of the World Health Organization. http://www.who.int/rabies/Global_distribution_risk_humans_contracting_rabies_2011.png?ua=1
Rabies is usually transmitted to humans from the deep bite or scratch of an infected animal. Domestic dogs are responsible for more than 99% of human rabies cases throughout the world. According to the WHO, “while infected domestic dogs cause human rabies deaths in Africa and Asia; in the Americas, Australia and Europe, bats are the primary source of human rabies infections.” Children are disproportionately affected by rabies. Forty percent of people who are bitten by suspected rabid animals are children under 15 years of age.
No tests are available to determine if a person is infected with rabies before they show clinical symptoms. Once a person begins to show clinical symptoms of rabies, the disease is almost always fatal. There have been a few cases of people developing rabies symptoms and surviving, with the use of the Milwaukee Protocol. In 2004, a Wisconsin teenager was bitten by an infected bat. She did not seek medical treatment and did not receive PEP. Dr. Willoughby, an infectious disease specialist at the Children’s Hospital of Wisconsin near Milwaukee, tried an experimental treatment that included an induced coma and antiviral medication. The teen survived with few lasting complications. However, many experts caution that the Milwaukee Protocol is not the cure for rabies, at least not yet. The first 43 human rabies cases where doctors attempted to replicate the Milwaukee Protocol resulted in only five survivors. Admittedly, five survivors are pretty good for a nearly always fatal disease, but not enough to say that the Milwaukee Protocol is a cure for human rabies.
Vaccinating dogs is the most cost effective way to prevent human rabies deaths because it results in a decrease in the global deaths attributable to rabies and a decrease in the need for post-exposure prophylaxis (PEP). Post-exposure prophylaxis is the administration of rabies immunoglobulin and rabies vaccine to an exposed person immediately after exposure, in order to prevent infection. Timely PEP can prevent the onset of rabies symptoms and death. However, PEP is expensive and not widely available in many of the resource poor settings with high rabies burden. Eighty percent of dog-mediated rabies deaths occur in rural areas that lack awareness about, and access to, PEP.
Figure 2. The 2015 World Rabies Day logo. Courtesy of the Global Alliance for Rabies Control. http://logos.rabiesalliance.org.s3-website-us-east-1.amazonaws.com/englishweb.jp
Rabies elimination is achievable for many of the countries with a high burden of dog-mediated rabies cases. Achieving a dog vaccination rate of at least 70% is accepted as the most effective way to prevent human rabies deaths. Rabies transmitted by dogs has been eliminated in many Latin American countries including Chile, Costa Rica, Panama, Uruguay, most of Argentina, the states of Sao Paulo and Rio de Janeiro in Brazil, and large parts of Mexico and Brazil. A Bill and Melinda Gates Foundation project, led by WHO, has made great strides against human rabies cases in the Philippines, South Africa and Tanzania. Furthermore, many countries in WHO South-East Asia Region have begun elimination campaigns with the goal of meeting the 2020 target for regional rabies elimination. Bangladesh, for example, launched an elimination program in 2010 and has seen human rabies deaths decrease by 50% during 2010-2013.
While there are still challenges in achieving a high vaccination rate in some areas of the world, such as vaccine availability and community support, some countries have been able to achieve rabies elimination. Events like World Rabies Day help draw attention to the high burden of rabies in resource poor settings and help to highlight the work being done to eliminate rabies.