Rabies is a virus-based zoonosis that is supposed to be available in more than 150 countries across all the continents except Antarctica. Many countries where the disease occurs are always supposed to be ready to face the outbreak of rabies as it is one of the most well-researched diseases. The disease is also said to be cent percent preventable. However, rabies causes many deaths every year despite the preparedness of many countries to face the rabid disaster. According to World Health Organization (WHO), rabies affects children the most as four out of every ten deaths are children under the age of 15. Since the nature of the disease is widespread it is understood to threaten more than 3 billion humans in Asia and Africa, especially those living in rural villages with less or no access to vaccines or other forms of treatments. According to the data of the Global Alliance for Rabies Control (2011), rabies is understood to cause an estimated 55,000 human deaths every year in Africa and Asia alone. Hence, this disease must be well taken care of.
In Bhutan, most cases of rabies are recorded from the southern frontiers along the Indo-Bhutan border (Figure 1) and the vector for transmission of the disease to human and domestic livestock is invariably domestic dogs. Dogs live freely in the villages and towns in Bhutan and the risk of transmission to humans and domestic livestock is very high if a dog is infected with the virus.
WHAT CAUSES RABIES AND HOW DO YOU CONTRACT THIS INFECTION?
Rabies infects the central nervous system and renders an infected individual mentally unstable. It is transmitted through the bite of infected animals and affects warm-blooded animals. The non-bite route of transmission of the disease is through bat caves. The bat caves are supposed to have rabies and transmit them to anyone venturing into the caves. Therefore, it is advisable not to visit bat caves unprotected. The vampire bat (Desmodus rotundus) is an asymptomatic carrier and can spread to any animals that come into contact. The other known reservoirs of the rabies virus are jackals, wolves, and mongooses. Skunks, raccoons, bats, and foxes are some species most frequently infected by the disease. The opossum is the only species considered to be fairly resistant to rabies.
ENZOOTIC WORLDWIDE
Rabies is enzootic worldwide. However, due to some control measures, countries like Australia, Bahamas, Bahrain, Brunei, Cyprus, Fiji, Hawaii, Hong Kong, New Guinea, New Zealand, Papua, Singapore, and Turks are considered free of disease at the moment, while Iceland, Japan, and the UK have eradicated the disease from their countries. The map below (Figure 2) exemplifies that this disease is widespread, far-reaching, and in-discriminatory.
This paper intends to talk about the clinical signs of rabies, how it comes into contact and spread between animal and human populations, and summarizes the options to control this zoonotic infection. The vital message this article intends to send is to let the people know about this dangerous disease so that those susceptible populations will visit the treatment centers if rabies is suspected.
Rabies infects the central nervous system and renders an infected individual mentally unstable. It is transmitted through the bite of infected animals and affects warm-blooded animals. The non-bite route of transmission of the disease is through bat caves. The bat caves are supposed to have rabies and transmit them to anyone venturing into the caves. Therefore, it is advisable not to visit bat caves unprotected. The vampire bat (Desmodus rotundus) is an asymptomatic carrier and can spread to any animals that come into contact. The other known reservoirs of the rabies virus are jackals, wolves, and mongooses. Skunks, raccoons, bats, and foxes are some species most frequently infected by the disease. The opossum is the only species considered to be fairly resistant to rabies.
Figure 1. Indo-Bhutan border map. The orange color is Bhutan while the green is India (Photo: http://upload.wikimedia.org/wikipedia/commons/5/57/India_Bhutan_Locator)
ENZOOTIC WORLDWIDE
Rabies is enzootic worldwide. However, due to some control measures, countries like Australia, Bahamas, Bahrain, Brunei, Cyprus, Fiji, Hawaii, Hong Kong, New Guinea, New Zealand, Papua, Singapore, and Turks are considered free of disease at the moment, while Iceland, Japan, and the UK have eradicated the disease from their countries. The map below (Figure 2) exemplifies that this disease is widespread, far-reaching, and in-discriminatory.
This paper intends to talk about the clinical signs of rabies, how it comes into contact and spread between animal and human populations, and summarizes the options to control this zoonotic infection. The vital message this article intends to send is to let the people know about this dangerous disease so that those susceptible populations will visit the treatment centers if rabies is suspected.
Figure 2. Rabies distribution worldwide (Map Courtesy WHO, 2008)
ETIOLOGY
In Latin rabies means madness and the disease has been known by various names like hydrophobia (fear of water) and lyssa (as it is caused by lyssaviruses). It belongs to the Rhabdovirus family and can be destroyed by sunlight and UV radiation. It can also be inactivated by strong acids and bases (BPL 1:5000 to 1:10,000) including formalin. It is known to remain alive in 50% GS/pure glycerol for weeks at RT or several months at 40C (fixed and street virus and urban and sylvatic virus).
In Latin rabies means madness and the disease has been known by various names like hydrophobia (fear of water) and lyssa (as it is caused by lyssaviruses). It belongs to the Rhabdovirus family and can be destroyed by sunlight and UV radiation. It can also be inactivated by strong acids and bases (BPL 1:5000 to 1:10,000) including formalin. It is known to remain alive in 50% GS/pure glycerol for weeks at RT or several months at 40C (fixed and street virus and urban and sylvatic virus).
PATHOGENESIS
The virus takes a centripetal movement from the site of the bite to Central Nervous System via peripheral nerves and then centrifugal to the salivary gland and other tissues of the body. From the bite site to the brain through the peripheral nerves and spinal cord and as the virus reach the brain there is encephalomyelitis (inflammation of the brain and spinal cord). Viruses then reach the salivary glands and saliva. Infected Raccoons die within 7 days after the exhibition of clinical symptoms and the virus incubates for 3-12 days without any signs. Shedding of the virus occurs even before clinical signs are observed which promotes transmission (CDC, 2011).
The virus takes a centripetal movement from the site of the bite to Central Nervous System via peripheral nerves and then centrifugal to the salivary gland and other tissues of the body. From the bite site to the brain through the peripheral nerves and spinal cord and as the virus reach the brain there is encephalomyelitis (inflammation of the brain and spinal cord). Viruses then reach the salivary glands and saliva. Infected Raccoons die within 7 days after the exhibition of clinical symptoms and the virus incubates for 3-12 days without any signs. Shedding of the virus occurs even before clinical signs are observed which promotes transmission (CDC, 2011).
CLINICAL SIGNS
The incubation period varies from 2-12 weeks and in rare cases shows some signs in less than 10 days or more than six months in carnivores and bats. The victim shows marked changes in behavior and exhibits furious nature during the excitation phase. In foxes and skunks, it would last from 1-6 days and produce saliva that has a high titer of the virus. The animal gets restless and shows biting tendencies. Alternation in barking sounds (paralysis of laryngeal muscle) becomes distinctly visible. The animal gets less aggressive but shows the problem in coordination with frequent muscle tremors. Finally, the animal gets paralyzed, it prostrates and dies.
The infected animal also would exhibit Hydro-phobia which is not a normal feature in animals. The clinical course of the disease lasts 2-4 days in foxes, 3-5 days in raccoons, and 4-9 days in skunks. They get dumb, get paralyzed, and die ultimately. Similar symptom of rabies infection is seen in distemper, hepatitis, listeriosis, tetanus, botulism ad parasitic infestation; plant/chemical toxin. However, the surest way to diagnose the disease is in the laboratory alone.
The incubation period varies from 2-12 weeks and in rare cases shows some signs in less than 10 days or more than six months in carnivores and bats. The victim shows marked changes in behavior and exhibits furious nature during the excitation phase. In foxes and skunks, it would last from 1-6 days and produce saliva that has a high titer of the virus. The animal gets restless and shows biting tendencies. Alternation in barking sounds (paralysis of laryngeal muscle) becomes distinctly visible. The animal gets less aggressive but shows the problem in coordination with frequent muscle tremors. Finally, the animal gets paralyzed, it prostrates and dies.
The infected animal also would exhibit Hydro-phobia which is not a normal feature in animals. The clinical course of the disease lasts 2-4 days in foxes, 3-5 days in raccoons, and 4-9 days in skunks. They get dumb, get paralyzed, and die ultimately. Similar symptom of rabies infection is seen in distemper, hepatitis, listeriosis, tetanus, botulism ad parasitic infestation; plant/chemical toxin. However, the surest way to diagnose the disease is in the laboratory alone.
DIAGNOSIS
Rabies can be diagnosed by the animal’s demonstration of Negri bodies (Hippocampus, cerebellum, or cerebral cortex), conducting FAT, other biological tests, virus isolation, and identification
IMMUNITY
One can remain immune to the diseases by monitoring the anti-rabies vaccine before exposure and or after exposure. No live vaccine should be used in a wild animal. Experimenting with tissue culture and using BPL-inactivated vaccines are helpful.
One can remain immune to the diseases by monitoring the anti-rabies vaccine before exposure and or after exposure. No live vaccine should be used in a wild animal. Experimenting with tissue culture and using BPL-inactivated vaccines are helpful.
CONTROL
Control of the disease once spread can be done by the following methods.
ü Vaccination
ü Control and eventual elimination of the disease from wildlife reservoirs and vector population
ü Practical success depends on carefully planned and executed programs, utilizing effective vaccine and control procedures for domestic animal species
ü Mass immunization of dogs and cats
ü Elimination of stray dogs
ü Rabies education programs
ü Use of oral ERA vaccines (Switzerland)
ü Strategies to control densities of wildlife population
In Bhutan, the management of the dog population through the implementation of a rabies control plan call a Capture-Neuter-Vaccinate Release (CNVR) program is being conducted in collaboration with Humane Society International.
Control of the disease once spread can be done by the following methods.
ü Vaccination
ü Control and eventual elimination of the disease from wildlife reservoirs and vector population
ü Practical success depends on carefully planned and executed programs, utilizing effective vaccine and control procedures for domestic animal species
ü Mass immunization of dogs and cats
ü Elimination of stray dogs
ü Rabies education programs
ü Use of oral ERA vaccines (Switzerland)
ü Strategies to control densities of wildlife population
In Bhutan, the management of the dog population through the implementation of a rabies control plan call a Capture-Neuter-Vaccinate Release (CNVR) program is being conducted in collaboration with Humane Society International.
HOW TO PREVENT A RABIES INFECTION
There are two basic methods to prevent rabies. The first one is about how to prevent infection in human beings and domestic livestock including pets while the second one is about how to deal with possible infections.
There are two basic methods to prevent rabies. The first one is about how to prevent infection in human beings and domestic livestock including pets while the second one is about how to deal with possible infections.
Rabies can be transmitted by any warm-blooded animal and humans usually are infected due to transmission through dogs. However, it can be prevented if proper care is taken and the following are some of the crucial steps in preventing the disease.
The following steps are recommended for the prevention of infection in human beings and domestic livestock. Of the two aforementioned methods, the following five steps must be taken in the first one which is prevention from infection in human and domestic livestock are:
The following steps are recommended for the prevention of infection in human beings and domestic livestock. Of the two aforementioned methods, the following five steps must be taken in the first one which is prevention from infection in human and domestic livestock are:
1. Vaccination of pets
The most common way for humans to get rabies infections is through their pets. Therefore, having to vaccinate one’s pet animals like dogs, cats, and other such domestic animals is very important for prevention for oneself as well as the animals. Ask the nearest vet to have your pet animals vaccinated.
The most common way for humans to get rabies infections is through their pets. Therefore, having to vaccinate one’s pet animals like dogs, cats, and other such domestic animals is very important for prevention for oneself as well as the animals. Ask the nearest vet to have your pet animals vaccinated.
2. Monitor and Supervise pet animals when they are allowed to move out
Avoid one’s pet animals to come in touch with stray domestic animals as well as wild animals. Some animals like raccoons, ferrets, bats, opossums, and squirrels can carry rabies without any physically visible symptoms. Therefore, pets must not be allowed to come into contact with these groups of animals. A leash or a fence may be constructed to keep one's pets away from such animals. If at all one’s pets have to be kept outdoors, necessary advice must be sought from the relevant disease control authorities of the concerned local area if there are any rabies outbreaks.
Avoid one’s pet animals to come in touch with stray domestic animals as well as wild animals. Some animals like raccoons, ferrets, bats, opossums, and squirrels can carry rabies without any physically visible symptoms. Therefore, pets must not be allowed to come into contact with these groups of animals. A leash or a fence may be constructed to keep one's pets away from such animals. If at all one’s pets have to be kept outdoors, necessary advice must be sought from the relevant disease control authorities of the concerned local area if there are any rabies outbreaks.
3. Reduction of stray animal numbers in the community
Stray animals around must be either eliminated or treated for rabies. The nearest vet center must be consulted for carrying out such population control works including the castration programs for stray animals. Having one’s pets spayed or neutered is very important as well. Ensure that children do not handle animals that are not treated. Rabies control in Bhutan is done through manipulation of the dog population through a Capture-Neuter-Vaccinate Release (CNVR) program supported by Humane Society International. The effectiveness is yet to be measured though.
Stray animals around must be either eliminated or treated for rabies. The nearest vet center must be consulted for carrying out such population control works including the castration programs for stray animals. Having one’s pets spayed or neutered is very important as well. Ensure that children do not handle animals that are not treated. Rabies control in Bhutan is done through manipulation of the dog population through a Capture-Neuter-Vaccinate Release (CNVR) program supported by Humane Society International. The effectiveness is yet to be measured though.
4. Advice people not to handle wild animals
Handling of wild animals through an attempt to feed or attract them by use of means that are not ethical around one's locality must be avoided. One must never adopt wild animals because if one is around wild animals, there is every risk ones can contract rabies if one comes across infected animals.
5. Being careful once one is away from home country.
Few countries have high rabies infection rates. Therefore, one needs to be extra careful if he/she enters such countries. Consultation with the doctor, travel clinics, and visiting available medical facilities can help one to be away from rabies infection. Knowing the risk of exposure to the disease rabies (pre-exposure prophylaxis), and what to do if you are exposed is very important to prevent rabies.
Handling of wild animals through an attempt to feed or attract them by use of means that are not ethical around one's locality must be avoided. One must never adopt wild animals because if one is around wild animals, there is every risk ones can contract rabies if one comes across infected animals.
5. Being careful once one is away from home country.
Few countries have high rabies infection rates. Therefore, one needs to be extra careful if he/she enters such countries. Consultation with the doctor, travel clinics, and visiting available medical facilities can help one to be away from rabies infection. Knowing the risk of exposure to the disease rabies (pre-exposure prophylaxis), and what to do if you are exposed is very important to prevent rabies.
The second method of prevention which is dealing with potential rabies infection is the following protocol:
1. If one is bitten, sought immediate medical attention
As soon as one is bitten by a dog, wild animal, or any such animal that has the potential to carry rabies, consulting the nearest doctor immediately is important. Plus, if your pet has been bitten visit the veterinary hospital immediately. Waiting can make the infection worse. As such, immediate action must be taken.
As soon as one is bitten by a dog, wild animal, or any such animal that has the potential to carry rabies, consulting the nearest doctor immediately is important. Plus, if your pet has been bitten visit the veterinary hospital immediately. Waiting can make the infection worse. As such, immediate action must be taken.
2. Treating the wound before reaching the hospital
If the local doctor is out of station or the veterinary hospital is closed, the wound needs to be cleaned using the following method.
a. Clean the wound with soap and water. World Health Organization advises that rabies can be eliminated at the site of infection by using chemicals or using physical means very effectively.
b. Using iodine or ethanol solution on the bitten area can be very helpful as they can kill the sensitive bacteria.
If the local doctor is out of station or the veterinary hospital is closed, the wound needs to be cleaned using the following method.
a. Clean the wound with soap and water. World Health Organization advises that rabies can be eliminated at the site of infection by using chemicals or using physical means very effectively.
b. Using iodine or ethanol solution on the bitten area can be very helpful as they can kill the sensitive bacteria.
3. Get rabies vaccination
If one who is bitten has not been vaccinated, the doctor would administer anti-rabies immune globulin that will help spread of the virus from the site of the bite. However, one might have to take the injection at regular intervals. The schedule normally is like 4 doses of vaccine with one dose right away and further doses on the 3rd, 7th, and 14th day. HRIG (Human Rabies Immune Globulin) must also be administered along with the first dose. But if one has been already vaccinated, he/she must get 2 doses of rabies vaccine, one taken right away and another on the 3rd day.
If one who is bitten has not been vaccinated, the doctor would administer anti-rabies immune globulin that will help spread of the virus from the site of the bite. However, one might have to take the injection at regular intervals. The schedule normally is like 4 doses of vaccine with one dose right away and further doses on the 3rd, 7th, and 14th day. HRIG (Human Rabies Immune Globulin) must also be administered along with the first dose. But if one has been already vaccinated, he/she must get 2 doses of rabies vaccine, one taken right away and another on the 3rd day.
CONCLUSION
There is no disagreement that rabies is a killer but there is also no disagreement that it is preventable. To keep away rabies is in the hands of people as we know how to prevent them. Therefore, we must strive to apply the very famous principle idea “Prevention is better than cure”. If we can prevent it, there is no way we will suffer from rabies infection and subsequent consequences. Therefore, prevention is the best way ahead for humans.
Further information, prevention, and treatment tips
Seek immediate veterinary assistance if your pet gets bitten by wild animals by any chance.
In America, raccoons are the main species that carry rabies while dogs are the main carriers of rabies in Asia, Africa, and Latin America.
One should never go near stray animals as they may be infected due to the non-monitoring of the vaccine.
Keep children away from other’s animals, and tell them to "Love your own, leave other animals alone".
Not all domesticated animals may be rabies-free. It could be fatal to assume that a rabies tag on the pet’s collar is safe as it does not guarantee an updated vaccination has been administered.
Warnings
Always visit the nearest hospital if you have been bit. Rabies is a very very dangerous disease in humans as it can kill the person infected if he/she is not treated.
There is no disagreement that rabies is a killer but there is also no disagreement that it is preventable. To keep away rabies is in the hands of people as we know how to prevent them. Therefore, we must strive to apply the very famous principle idea “Prevention is better than cure”. If we can prevent it, there is no way we will suffer from rabies infection and subsequent consequences. Therefore, prevention is the best way ahead for humans.
Further information, prevention, and treatment tips
Seek immediate veterinary assistance if your pet gets bitten by wild animals by any chance.
In America, raccoons are the main species that carry rabies while dogs are the main carriers of rabies in Asia, Africa, and Latin America.
One should never go near stray animals as they may be infected due to the non-monitoring of the vaccine.
Keep children away from other’s animals, and tell them to "Love your own, leave other animals alone".
Not all domesticated animals may be rabies-free. It could be fatal to assume that a rabies tag on the pet’s collar is safe as it does not guarantee an updated vaccination has been administered.
Warnings
Always visit the nearest hospital if you have been bit. Rabies is a very very dangerous disease in humans as it can kill the person infected if he/she is not treated.
References and Further Information are available from the following papers
Centers for Disease Control and Prevention (CDC), (2011), Wild animal surveillance. Available online http://www.cdc.gov/rabies/location/usa/surveillance/ wild_animals.html [Nov’2014]
Rabies, WHO, Available online http://www.who.int/rabies/epidemiology/ Rabiessurveillance.pdf [Access Nov’2014]
Tenzin, Wacharapluesadee, S., Denduangboripant, J., Dhand, N.K., Dorjee, J., D. Tshering, D., Rinzin, K., Raika, V., Dahal, N., Ward, M.P. Rabies virus strains circulating in Bhutan: implications for control. Epidemiology and Infection, 2011; 149: 1457−1462.
Tenzin, Dhand, N.K., Ward, M.P. Patterns of rabies occurrence in Bhutan between 1996 and 2009. Zoonoses and Public Health, 2011, 58: 463−471.
Tenzin, Dhand, N.K., Gyeltshen, T., Firestone, S., Zangmo, C., Dema, C., Gyeltshen, R., Ward, M.P. Dog bites in humans and estimating human rabies mortality in rabies endemic areas of Bhutan. PLoS Neglected Tropical Diseases, 2011; 5: 1391.
World Rabies Day Mission (2011), GARC - Global Alliance for Rabies Control 2014, Available online http://www.worldrabiesday.org/EN/world_rabies_day_mission.html (Accesses Nov’2011)
Centers for Disease Control and Prevention (CDC), (2011), Wild animal surveillance. Available online http://www.cdc.gov/rabies/location/usa/surveillance/ wild_animals.html [Nov’2014]
Rabies, WHO, Available online http://www.who.int/rabies/epidemiology/ Rabiessurveillance.pdf [Access Nov’2014]
Tenzin, Wacharapluesadee, S., Denduangboripant, J., Dhand, N.K., Dorjee, J., D. Tshering, D., Rinzin, K., Raika, V., Dahal, N., Ward, M.P. Rabies virus strains circulating in Bhutan: implications for control. Epidemiology and Infection, 2011; 149: 1457−1462.
Tenzin, Dhand, N.K., Ward, M.P. Patterns of rabies occurrence in Bhutan between 1996 and 2009. Zoonoses and Public Health, 2011, 58: 463−471.
Tenzin, Dhand, N.K., Gyeltshen, T., Firestone, S., Zangmo, C., Dema, C., Gyeltshen, R., Ward, M.P. Dog bites in humans and estimating human rabies mortality in rabies endemic areas of Bhutan. PLoS Neglected Tropical Diseases, 2011; 5: 1391.
World Rabies Day Mission (2011), GARC - Global Alliance for Rabies Control 2014, Available online http://www.worldrabiesday.org/EN/world_rabies_day_mission.html (Accesses Nov’2011)
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