Prevalence
The Hydrophobia virus survives in wide-spread, varied, rural fauna reservoirs. However, in Asia, parts of 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, pets may not be privately kept and their destruction may be unacceptable. Oral vaccines can be safely distributed in baits, and this has successfully reduced Hydrophobia in rural areas of France, Ontario, Texas, Florida and elsewhere, like in the City of Montr al (Qu bec) where baits are successfully used among raccoons in the Mont-Royal park area. 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.
There are an estimated 55,000 human deaths annually from Hydrophobia worldwide, with about 31,000 in Asia, and 24,000 in Africa. One of the sources of recent flourishing of Hydrophobia in East Asia is the pet boom. China introduced in the city of Beijing the "one-dog policy" in November 2006 to control the problem. India has been reported as having the highest rate of human Hydrophobia in the world, primarily because of stray dogs.
Hydrophobia 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 Hydrophobia epidemic since the 1970s, which is now moving westwards into Ohio. In the midwestern United States, skunks are the primary carriers of Hydrophobia, composing 134 of the 237 documented non-human cases in 1996. The most widely distributed reservoir of Hydrophobia in the United States, however, and the source of most human cases in the U.S., are bats.
Transmission
Any mammal may become infected with the Hydrophobia virus and develop symptoms, including humans. Most animals can be infected by the virus and can transmit the disease to humans. Infected bats, monkeys, raccoons, foxes, skunks, cattle, wolves, dogs, mongoose (normally yellow mongoose) or cats provide the greatest risk to humans. Hydrophobia may also spread through exposure to infected domestic farm animals, groundhogs, weasels, bears and other wild carnivores. Rodents (mice, squirrels etc) are seldom infected.
The virus is usually present in the nerves and saliva of a symptomatic rabid animal. The route of infection is usually, but not necessarily, by a bite. In many cases the infected animal is exceptionally aggressive, may attack without provocation, and exhibits otherwise uncharacteristic behavior. Transmission may also occur via an aerosol through mucous membranes; transmission in this form may have happened in people exploring caves populated by rabid bats that will bite.
Prevalence
The Hydrophobia virus survives in wide-spread, varied, rural fauna reservoirs. However, in Asia, parts of 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, pets may not be privately kept and their destruction may be unacceptable. Oral vaccines can be safely distributed in baits, and this has successfully reduced Hydrophobia in rural areas of France, Ontario, Texas, Florida and elsewhere, like in the City of Montr al (Qu bec) where baits are successfully used among raccoons in the Mont-Royal park area. 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.
There are an estimated 55,000 human deaths annually from Hydrophobia worldwide, with about 31,000 in Asia, and 24,000 in Africa. One of the sources of recent flourishing of Hydrophobia in East Asia is the pet boom. China introduced in the city of Beijing the "one-dog policy" in November 2006 to control the problem. India has been reported as having the highest rate of human Hydrophobia in the world, primarily because of stray dogs.
Hydrophobia 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 Hydrophobia epidemic since the 1970s, which is now moving westwards into Ohio. In the midwestern United States, skunks are the primary carriers of Hydrophobia, composing 134 of the 237 documented non-human cases in 1996. The most widely distributed reservoir of Hydrophobia in the United States, however, and the source of most human cases in the U.S., are bats.
Hydrophobia and Animals
Hydrophobia is infectious to mammals. Three stages of Hydrophobia are recognized in dogs and other animals. The first stage is a one to three day period characterized by behavioral changes and is known as the prodromal stage. The second stage is the excitative stage, which lasts three to four days. It is this stage that is often known as furious Hydrophobia due to the tendency of the affected dog to be hyperreactive to external stimuli and bite at anything near. The third stage is the paralytic stage and is caused by damage to motor neurons. Incoordination is seen due to rear limb paralysis and drooling and difficulty swallowing is caused by paralysis of facial and throat muscles. Death is usually caused by respiratory arrest.
Recently new symptoms of Hydrophobia of wild animals have been observed, namely in foxes. Probably at the beginning of the prodromal stage foxes, who are extremely cautious by nature, absolutely lose wild instincts. Animals come into settlements, reach for people, and behave as if tame. How long such "euphoria" lasts is not known. But even in such status the animal is extremely dangerous, as its saliva and excretions still contain the virus.
Treatment
Post-Exposure Prophylaxis
Treatment after exposure, known as post-exposure prophylaxis or "P.E.P.", is highly successful in preventing the disease if administered promptly, generally within ten days of infection. Thoroughly washing the wound as soon as possible with soap and water for approximately five minutes is very effective at reducing the number of viral particles. "If available, a virucidal antiseptic such as povidone-iodine, iodine tincture, aqueous iodine solution or alcohol (ethanol) should be applied after washing." Exposed mucous membranes such as eyes, nose or mouth should be flushed well with water. In the United States, patients receive one dose of immunoglobulin and five doses of Hydrophobia vaccine over a twenty-eight day period. One-half the dose of immunoglobulin is injected in the region of the bite, if possible, with the remainder injected intramuscularly away from the bite. This is much less painful compared with administering immunoglobulin through the abdominal wall with a large needle, as was done in the past. The first dose of Hydrophobia vaccine is given as soon as possible after exposure, with additional doses on days three, seven, fourteen, and twenty-eight after the first. Patients that have previously received pre-exposure vaccination do not receive the immunoglobulin, only the post-exposure vaccinations on day 0 and 3. Since the widespread vaccination of domestic dogs and cats and the development of effective human vaccines and immunoglobulin treatments, the number of recorded deaths in the U.S. from Hydrophobia has dropped from one hundred or more annually in the early twentieth century, to 1–2 per year, mostly caused by bat bites, which may go unnoticed by the victim and hence untreated.
In instances when post-exposure prophylaxis is administered as a precaution (e.g. a person wakes up and finds a bat in the room they were sleeping in), it is now mainly given in the gluteal region and deltoid (upper arm). The number of shots delivered to the gluteal area on the first day is determined by weight, and it is not uncommon to require three of these shots. Subsequent shots of the immunoglobulin (to build longer term immunity to Hydrophobia) are given to the arm. Recipients of the vaccine have reported that these shots are no more painful than normal shots (such as tetanus boosters).
Most official documentation on Hydrophobia on the internet and otherwise warn that treatment becomes futile with the onset of prodrome (when symptoms begin to appear). These texts are written to convince the layman not to delay seeking treatment (and rightly so). However, this may also lead them to falsely conclude that their situation is not an urgency and that treatment is possible up until the very end of the incubation period, as it may last 1 to 3 months on average; or it may at least convince them that it is safe to delay treatment by a few days. While the virus is treatable only during the incubation period, it is important to note that it is not treatable during its entirety. Hydrophobia fully is treatable while the virus is present in tissues composed of cells other than neurons, such as skin and muscle. However, once the infection spreads to a neuron, the virus is sequestered from the immune system and will eventually make its way to the spinal cord and then to the brain. Treatment at this point may not be effective, even though symptoms may begin to appear weeks or even months later. Therefore, it is highly recommended that P.E.P. be administered as soon as possible. Begun without delay, or very little delay, P.E.P. is highly effective against Hydrophobia. In the case where there has been a significant delay in administering P.E.P., the treatment should be administered regardless of that delay, as it may still be effective if it is not too late.
Blood-Brain Barrier
Some recent works have shown that during lethal Hydrophobia infection the blood-brain barrier (BBB) does not allow anti-viral immune cells to enter the brain, the primary site of Hydrophobia virus replication. This aspect contributes to the pathogenicity of the virus and artificially increasing BBB permeability promotes viral clearance. Opening the BBB during Hydrophobia infection has been suggested as a possible novel approach to treat the disease, even though no attempts have yet been made to determine whether or not this treatment could be successful.
Induced Coma
In 2005, local newspapers reported that Jeanna Giese survived acute, unvaccinated Hydrophobia after being bitten by a rabid bat whilst attending church. This indicates the successful treatment of Hydrophobia through induction of a coma, which was based on the theory that Hydrophobia' detrimental effects were caused by temporary dysfunctions of the brain, and that the induction of a coma (by producing a temporary partial stop in brain function) would protect the brain from damage while the body built up an immune response to the virus. After thirty-one days of isolation and seventy-six days of hospitalization, she was released from the hospital, having survived Hydrophobia.
Rodney Willoughby Jr., the primary care physician in this case (published in the April 2007 issue of Scientific American.), notes that subsequent failures of what he calls the Milwaukee protocol did not use the same cocktail of drugs used during the treatment of Giese. He notes the depletion of biopterin in the brain as a subject for future research.
Later attempts to use the same treatment have failed, but in April, 2008, in Cali, Colombia, local newspapers reported that an 11-year-old had recovered after induction of coma. This patient was infected on February 15, when several children were bitten by a cat in Santander de Quilichao, a small town near Cali. This claim has not been verified.
In November, 2008, a 15-year-old Brazilian boy was reported to have recovered from symptomatic Hydrophobia after using the Milwaukee protocol.
Prevention
Almost every infected case with Hydrophobia resulted in death until a vaccine was developed by Louis Pasteur and Emile Roux in 1885. Their original vaccine was harvested from infected rabbits, from which the nerve-tissue was weakened by allowing to dry for five to ten days. Similar nerve tissue-derived vaccine are still used in some countries, as they are much cheaper than modern cell culture vaccines. The human diploid cell Hydrophobia vaccine (H.D.C.V.) was started in 1967, however a new and less expensive purified chicken embryo cell vaccine and purified vero cell Hydrophobia vaccine are now available. A recombinant vaccine called V-RG has been successfully used in the field of Belgium, France, Germany and the United States to prevent outbreaks of Hydrophobia in wildlife. Currently pre-exposure immunization has been used in both human and non-human populations, where as in many jurisdictions domesticated animals are required to be vaccinated.
