Rabies

Rabies (from a Latin word meaning rage) is a viral disease that causes acute encephalitis in animals and people. It can affect most species of warm-blooded animals, but is rare among non-carnivores. In unvaccinated humans, rabies is almost invariably fatal once full-blown symptoms have developed, but post-exposure vaccination can prevent symptoms from developing.

Prevalence

Between 40,000 and 70,000 human beings die annually from rabies, with about 90% of those cases occurring in Asia. About 6 million people receive treatment annually after suspected exposure to rabies.

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Dog licensing, killing of stray dogs, muzzling and other measures contributed to the eradication of rabies from Great Britain in the early 20th century. More recently, large-scale vaccination of cats, dogs and ferrets has been successful in combatting rabies in some developed countries.

Related Topics:
Great Britain - 20th century

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Rabies virus survives in widespread, varied, rural wildlife reservoirs. However, in Asia, parts of Latin America and large parts of Africa, dogs remain the principal host. Mandatory vaccination of animals is less effective in rural areas. Especially in developing countries, animals may not be privately owned and their destruction may be unacceptable. Oral vaccines can be safely distributed in baits, and this has successfully impacted rabies in rural areas of France, Ontario, Texas, Florida and elsewhere. Vaccination campaigns may be expensive, and a cost-benefit analysis can lead those responsible to opt for policies of containment rather than elimination of the disease.

Related Topics:
France - Ontario - Texas - Florida

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Rabies was once rare in the United States outside the Southern states, but raccoons in the mid-Atlantic and northeast United States have been suffering from a rabies epidemic since the 1970s, which is now moving westwards into Ohiohttp://aepo-xdv-www.epo.cdc.gov/wonder/prevguid/m0045024/m0045024.asp. The particular variant of the virus has been identified in the southeastern United States raccoon population since the 1950s, and is believed to have traveled to the northeast as the result of infected raccoons being among those caught and transported from the southeast to the northeast by hunters attempting to replenish the declining northeast raccoon population (Nettles VF, Shaddock JH, Sikes RK, Reyes CR. "Rabies in translocated raccoons". Am J Public Health 1979;69:601-2.). As a result, urban residents of these areas have become more wary of the large but normally unseen urban raccoon population. It has become the common assumption that any raccoon seen in daylight is infected; certainly the reported behavior of most such animals appears to show some sort of illness, and autopsies usually confirm rabies. Whether as a result of increased vigilance or just the normal avoidance reaction to any animal not seen in the course of day to day life, such as a raccoon, there have been no documented human rabies cases as a result of this variant. This does not include, however, the greatly increasing rate of prophylactic rabies treatments in cases of possible exposure, which numbered less than 100 persons annually in New York State before 1990, for instance, but rose to approximately 10,000 annually between 1990 and 1995. At approximately $1500 per course of treatment, this represents a considerable public health expenditure. Raccoons do constitute approximately 50% of the approximately 8,000 documented animal rabies cases in the United States (Krebs JW, Strine TW, Smith JS, Noah DL, Rupprecht CE, Childs JE. "Rabies surveillance in the United States during 1995". J Am Vet Med Assoc 1996;204:2031-44). Domestic animals constitute only 8% of rabies cases (ibid.), but are increasing at a rapid rate.

Related Topics:
Southern states - Raccoon - 1970s - Ohio - 1950s - 1990 - 1995

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In the midwestern United States, skunks are the primary carriers of rabies, comprising 144 of the 237 documented animal cases in 1996. The most widely distributed reservoir of rabies in the United States, however, and the source of most human cases in the U.S., are bats. Nineteen of the 22 human rabies cases documented in the United States between 1980 and 1997 have been identified genetically as bat rabies. In many cases, victims are not even aware of having been bitten by a bat, assuming that a small puncture wound found after the fact was the bite of an insect or spider; in some cases, no wound at all can be found, leading to the hypothesis that in some cases the virus can be contracted via inhaling airborne aerosols from the vicinity of a bat or bats. For instance, the Centers for Disease Control and Prevention warned on May 9, 1997, that a woman who died in October, 1996 in Cumberland County, Kentucky and a man who died in December, 1996 in Missoula County, Montana were both infected with a rabies strain found in silver-haired bats; although bats were found living in the chimney of the woman's home and near the man's place of employment, neither victim could remember having had any contact with them. This inability to recognize a potential infection, in contrast to a bite from a dog or raccoon, leads to a lack of proper prophylactic treatment, and is the cause of the high mortality rate for bat bites.

Related Topics:
Skunk - 1996 - Bat - 1980 - 1997 - Aerosol - Centers for Disease Control and Prevention - May 9 - Cumberland County, Kentucky - Missoula County, Montana

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In case of an attack by a possibly rabid animal, most states in the United States allow the killing of the attacking animal. Because a rabies diagnosis requires that the brain tissue be preserved, it is recommended that rabid animals are not to be shot in the head.

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Australia is one of the few parts of the world where rabies has never been introduced. However, the Australian Bat Lyssavirus occurs naturally in both insectivorous and fruit eating bats (flying foxes) from most mainland states. Scientists believe it is present in bat populations throughout the range of flying foxes in Australia.

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Many territories, such as the United Kingdom, Ireland, Hawaii, and Guam, are free of rabies (although there may be a very low prevalence of rabies among bats in the UK; see below).

Related Topics:
United Kingdom - Ireland - Hawaii - Guam

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