Rabies vaccine
Encyclopedia
Rabies vaccine is a vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...

 used to control rabies
Rabies
Rabies is a viral disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms...

. Rabies can be prevented by vaccination
Vaccination
Vaccination is the administration of antigenic material to stimulate the immune system of an individual to develop adaptive immunity to a disease. Vaccines can prevent or ameliorate the effects of infection by many pathogens...

, both in humans and other animals.

In animals

Currently, pre-exposure immunization
Immunization
Immunization, or immunisation, is the process by which an individual's immune system becomes fortified against an agent ....

 has been used on domesticated and normal non-human populations. In many jurisdictions, domestic dogs, cats, and ferrets are required to be vaccinated.

Imrab is an example of a veterinary rabies vaccine containing the Pasteur strain of killed rabies virus. Several different types of Imrab exist, including Imrab, Imrab 3, and Imrab Large Animal. Imrab 3 has been approved for ferret
Ferret
The ferret is a domesticated mammal of the type Mustela putorius furo. Ferrets are sexually dimorphic predators with males being substantially larger than females. They typically have brown, black, white, or mixed fur...

s and, in some areas, pet skunk
Pet skunk
A pet skunk is a skunk kept by humans for companionship and enjoyment. Although capable of living indoors with humans similarly to dogs or cats, pet skunks are relatively rare, partly due to restrictive laws and the complexity of their care...

s.

History

Virtually every infection with rabies resulted in death, until the two French scientists Louis Pasteur
Louis Pasteur
Louis Pasteur was a French chemist and microbiologist born in Dole. He is remembered for his remarkable breakthroughs in the causes and preventions of diseases. His discoveries reduced mortality from puerperal fever, and he created the first vaccine for rabies and anthrax. His experiments...

 and Emile Roux developed the first rabies vaccination in 1885. This vaccine was first used on a human on July 6, 1885, on nine-year old Joseph Meister
Joseph Meister
Joseph Meister was the first person to be inoculated against rabies by Louis Pasteur, and the first person to be successfully treated for the infection....

 (1876–1940), who had been mauled by a rabid dog.

Their vaccine consisted of a sample of the virus harvested from infected (and necessarily dead) rabbits, which was weakened by allowing it to dry for 5 to 10 days. Similar nerve tissue-derived vaccines are still used now in some countries, and while they are much cheaper than modern cell culture vaccines, they are not as effective. Neural tissue vaccines also carry a certain risk of neurological complications.

Modern vaccines

The human diploid cell rabies vaccine (H.D.C.V.) was started in 1967. Human diploid cell rabies vaccines are made using the attenuated Pitman-Moore L503 strain of the virus. Human diploid cell rabies vaccines have been given to more than 1.5 million humans as of 2006.

Aside from vaccinating humans, another approach was also developed by vaccinating dogs to prevent the spread of the virus. In 1979 the Van Houweling Research Laboratory of the Silliman University
Silliman University
Silliman University is a private research university located in Dumaguete, Philippines. Established in 1901 as Silliman Institute by the Presbyterian Board of Foreign Missions, it was the first American private school to be founded in the country. The University is named after Dr...

 Medical Center in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

, then headed by Dr. George Beran, developed and produced a dog vaccine that gave a three-year immunity from rabies
Rabies
Rabies is a viral disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms...

. The development of the vaccine resulted in the elimination of rabies in many parts of the Visayas
Visayas
The Visayas or Visayan Islands and locally known as Kabisay-an gid, is one of the three principal geographical divisions of the Philippines, along with Mindanao and Luzon. It consists of several islands, primarily surrounding the Visayan Sea, although the Visayas are considered the northeast...

 and Mindanao
Mindanao
Mindanao is the second largest and easternmost island in the Philippines. It is also the name of one of the three island groups in the country, which consists of the island of Mindanao and smaller surrounding islands. The other two are Luzon and the Visayas. The island of Mindanao is called The...

 Islands. The successful program in the Philippines was later used as a model by other countries, such as Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

 and the Yucatan State
Yucatán
Yucatán officially Estado Libre y Soberano de Yucatán is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 106 municipalities and its capital city is Mérida....

 of Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, in their fight against rabies conducted in collaboration with the World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...

.

In addition to these developments, newer and less expensive purified chicken embryo cell vaccine, and purified Vero cell rabies vaccine are now available. The purified Vero cell rabies vaccine uses the attenuated Wistar strain of the rabies virus, and uses the Vero cell line as its host.

Recombinant rabies vaccine (V-RG)

In 1984 researchers at the Wistar Institute
Wistar Institute
The Wistar Institute is a biomedical center, with a focus on cancer research and vaccine development. It is located in the University City section of Philadelphia, Pa...

 developed a recombinant
Recombinant DNA
Recombinant DNA molecules are DNA sequences that result from the use of laboratory methods to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in biological organisms...

 vaccine called V-RG by inserting the glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...

 gene from rabies into a vaccinia
Vaccinia
Vaccinia virus is a large, complex, enveloped virus belonging to the poxvirus family. It has a linear, double-stranded DNA genome approximately 190 kbp in length, and which encodes for approximately 250 genes. The dimensions of the virion are roughly 360 × 270 × 250 nm, with a mass of...

 virus. The V-RG vaccine has since been commercialised by Merial
Merial
Merial is a multinational animal health company. It was formed as a joint venture between Merck & Co. and Sanofi-Aventis in 1997. Merial is now the animal health subsidiary of Sanofi-Aventis. Merial is a company leader in innovation, and provides an ample range with products to improve the...

 under the trademark Raboral. It is harmless to humans and has been shown to be safe for various species of animals that might accidentally encounter it in the wild, including birds (gulls, hawks, and owls).

V-RG has been successfully used in the field in Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 to prevent outbreaks of rabies in wildlife
Wildlife
Wildlife includes all non-domesticated plants, animals and other organisms. Domesticating wild plant and animal species for human benefit has occurred many times all over the planet, and has a major impact on the environment, both positive and negative....

. The vaccine is stable under relatively high temperatures and can be delivered orally, making mass vaccination of wildlife possible by putting it in baits. The plan for immunization of normal populations involves dropping bait containing food wrapped around a small dose of the live virus. The bait would be dropped by helicopter concentrating on areas that have not been infected yet. Just such a strategy of oral immunization of foxes in Europe has already achieved substantial reductions in the incidence of human rabies. In November 2008, Germany had been free of new cases for two years and is therefore currently believed as being rabies-free, together with few other countries (see below). A strategy of vaccinating “neighborhood dogs” in Jaipur
Jaipur
Jaipur , also popularly known as the Pink City, is the capital and largest city of the Indian state of Rajasthan. Founded on 18 November 1727 by Maharaja Sawai Jai Singh II, the ruler of Amber, the city today has a population of more than 3.1 million....

, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, combined with a sterilization program, has also resulted in a large reduction in the number of human cases.

Duration of immunity

The duration of immunity afforded to humans by a two injection vaccination course was found to be between 2 to 3 years. Following administration of a booster dose (recommended at one year), one study found 97% of immuno-competent individuals demonstrate protective levels of neutralizing antibodies at 10 years.
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