Rabies And Animal Infections Biology Essay

Published: Last Edited:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

Rabies is an acute viral infection and can be fatal to humans (1). Humans can be infected by being bitten by any infected animals usually by a dog (1). Any warm blooded animals can be infected by canine rabies and can be deadly (1). The virus has cylindrical shape and the nucleic acid is ribonucleic acid (1). The virion is enveloped and covered with projections (1). It is to be sure that the virus is transmitted by saliva from wound through sensory nerves to the central nervous system (1). The diagnosis for humans is by observing the Negri bodies in the animal's brain inoculated with the person's saliva (1). A dog is observed for ten days when it has bitten a person to find signs of rabies (1). If rabies is present, the dog will be killed, so the Negri bodies can be observed (1). Rabies could happen anywhere, especially from developing countries (1). Many cases of rabies had been report from the past few years (1). When a body has been infected by rabies virus, it could remain latent in the tissues (1). If this happened, antibody or immunogenic vaccine has to be provided to prevent the virus from invading the central nervous system (1).

Rabies vaccine are available in the in the United States (1). Vaccines are grown from cell cultures from monkey or human (1). In South and Central America, not only dogs or any other animal transmit the rabies virus (1). Vampire bats and fruit- and insect eating bats also transmit the virus to human beings (1). With the transmission of rabies virus by bat being proved, it adds to the problem in controlling the virus (1). Bats also oppose another challenge for rabies in North America (3). Lack of history of bat exposure can be a challenge for treating rabies, and bat bites can be sometimes be unfamiliar (3).

Rhabdoviridae in the virus classification is where rabies belong (2). Mostly all mammals are more likely to suffer from rabies infection (2). Rabies has an incubation period that last from weeks to months (2). During those times, the virus is not able to transmit until the virus reached the brain (2). Not all bites will result to rabies infections (2). Any animals that had been vaccinated could still have antibodies to stop rabies from starting (2). A study of how rabies is spread and how to control it had been done in past decades (2). Unfortunately, the studies were focused only on wild red foxes or bats (2). Culling, vaccination, culling, and vaccination are the three strategies of how to control rabies (2). They had found out that vaccination is the best choice to control rabies and culling would not be a good choice (2).

September 8, 2007 was marked as World Rabies Day by The World Health Organization, so it can bring attention to those people who do not accept the seriousness of the virus infection. (3) India has the most annual death because of the virus (3). Some occurs more often in Southeast Asia, Oceana, and Latin America (3). The diagnosis of rabies virus can be a challenging because of its long incubation period, a lack of specific symptoms, and neurologic symptoms (3). The rabies infection will evolve into encephalitis which also includes some symptoms of hydrophobia, hyper excitability, and autonomic dysfunction (3). Most of the patients who had these symptoms eventually die within a few days (3). Three to ten days following the onset of the symptoms is usually the amount of time the patients have until they die, but their life can be prolong with intensive medical care (4). Direct fluorescent anti body testing of sample of fresh brain tissue is the current standard, but reverse transcriptase polymerase chain reaction of brain tissue, and supportive histopathology of brain tissue are also acceptable (3). Support histopathology of brain tissue looks for signs of leptomeningeal intracytoplasmic inclusion bodies (3). There are no antiviral or immunomodulating drug had been found to be effective in treating the rabies virus infection (3)

Pre exposure prophylaxis and post exposure prophylaxis are the two recommended vaccine strategies for people for high risk group and based on a risk of exposure (3). Only selective people who are going to a high risk exposure place like travelers that will travel to a place with limited access to human rabies immune globulin will get the pre exposure prophylaxis (3). It is because of the estimated cost of 3.3 million people saved (3). For post exposure prophylaxis, treating the wound will include washing with soap and flushing of the wound (3). Then follow by applying 70% ethanol alcohol or povidone iodine solution (3). This step is crucial and very important to prevent the infection. A follow up of human rabies immune globulin should be applied directly to the wound (3). Rabies vaccine and human immune globulin should not be applied at the same time (3). The two should be applied seven days apart, and should not use the same syringe and the injection site (3). The post exposure prophylaxis should be given depends on the time it was exposed (3).

Acute respiratory distress syndrome can be associated with rabies (4). ARDS is cause by infectious diseases and had been reported to happen in Taiwan (4). It is rare to have ARDS with rabies virus infection (4). A case associated a 36 year-old woman died after being bitten by a wild dog in mainland China (4). The woman had a rabies virus infection because of the bite from the wild dog (4). Severe respiratory distress was developed six days after being admitted (4). Then a lumbar puncture was performed and chest radiographs were taken because of dyspnoea and hypoxia (4). Unfortunately for the woman, she died eight hours following the onset of severe respiratory distress (4). They examined her lung and brain during autopsy (4). They found that the lung and brain were stained with haematoxylin, eosin, and avidin biotin complex (4). During her admission, her lungs were clear when shown in chest radiography (4). The patient at that time was lucid, oriented, and cooperative (4). After a while, she became irritable, so a tranquilizer and sedative were given (4). Persistent dyspnoea, hypoxia, and hypotension happen, and her symptoms of ARDS became severe (4). Chest radiography revealed ARDS (4).They found during autopsy that her lungs were heavier when it is compared to a normal weight of a lungs (4).

A study had been conducted to evaluate abbreviated pre exposure rabies vaccination schedules that would reduce the cost and the time required for completion (5). Ninety six volunteered aged eight to four and a ratio of male to female of 41:45 were recruited (5). During the study year, none were at risk of rabies exposure (5). The volunteers were divided into six groups randomly, and they were given abbreviated vaccine schedules using WHO-recognized purified Vero cell rabies vaccine or purified chick embryo cell rabies vaccine (5). The schedule that was selected was to determine whether someone could achieve immune memory lasting at least one year that would determine in a satisfactory accelerated neutralizing antibody response when boosters are provided in a simulated rabies exposure 360 days later (5).All of the volunteer signed a consent form after being told of the purpose of the study (5). They were told that if they had an event of exposure, they have to obtain booster injections and contact one of the investigators (5). Neutralizing rabies antibodies were concluded at the immunology of the institute using the rabies fluorescent focus inhibition test (5). The study that had been conducted had been approved by the ethics committee of the Thai Red Cross Society (5).

In the result of the study, there were no result of aggressive questioning, but a minor itching and erythema at the injection site (5). No neutralizing anti body titers was detected on all subjects on day 0 (5). Others who had received PREP and were tested had detected neutralizing anti body titers (5). Others who had received PEP in the first day of the study had detectable titers on the 360 day of the study before they were given the booster injections (5). From the volunteers that had been tested responded with an accelerated immune response on day 367 (5). A group of the volunteers were recruited from WHO category II rabies exposed regular clinic patients (5). Those who accepted 0.1 ml tissue cultures rabies vaccine injected at both deltoid regions showed immune memory for at least one year (5). The two booster injection resulted to accelerated immune response a year later, and shows that immunoglobulin might not be needed if exposure occurred within a year (5). The study became possible because of the financial support from Aventis Pasteur Co. and the Thai Red Cross Society (5).

Another study had been conducted to examine the characteristics of rabies PEP administration in travelers returning from destinations in Africa, Southeast Asia, and the Pacific region (6). Patients that had been selected had acquired animal related injury while in a different country and are seeking care in one of the clinic that treats rabies PEP on their return to their home country (6). The information from the patients cases of rabies include pre exposure status, type of contact with the infected animal, and the nature of rabies PEP was collected (6). There are three categories of animal contact defined according to WHO guide for PEP (6). Category I is only mild injury that includes touching or feeding of animals and licks on contact skin (6). Category II is moderate injury; these injuries are nibbling of uncovered skin and minor scratches or abrasions without bleeding (6). Category III is defined as severe injury which are single or multiple transdermal bites or scratches, licks on broken skin or mucous membrane, and contact with bats (6). The place of exposure was grouped into fifteen regions; North America, South America, Central America, Caribbean, Eastern Europe, Western Europe, Oceana, Australia, South central Asia, Southeast Asia, Eastern and North Asia, Western Asia, North Africa, Sub Saharan Africa, and Antarctica (6). Countries that have a high risk of rabies for travelers were determined from recent published studies, WHO, and Center of Disease Control sources (6). Human Rabies Immune Globulin is given into and around the wound (6).

The 259 patients know about the information about the rabies pre exposure prophylaxis; however, only 6.8% were vaccinated before traveling to rabies endemic countries (6). About 75.4% of the travelers experienced the category three of animal contact (6). In the 197 travelers who had experienced category three of animal contact had severe hand and facial injuries (6). For the animals that cause these injuries, dogs were responsible for fifty percent of the injuries including the severe facial and hand bite (6). Other animals such as animals and monkeys are the other animals responsible for the injuries (6). The 170 travelers that experienced category III injuries in rabies endemic countries and had not been vaccinated before traveling, 19 of them received the vaccine and RIG in the country where they had been exposed (6). Eighty one of those only received the vaccine and two were not treated (6).

In conclusion, rabies virus infection is very fatal to human beings and can be deadly. It can also be obtained from many different infected animals. It can even be obtained from our pets if infected with rabies virus infection. It occurs all over the world. Fortunately many people are trying to minimize the number of people that are getting the rabies virus infection. There are also some precautions that can be done before going to a high risk exposure of rabies. It can be very risky to people visiting places that do not have vaccine to treat rabies virus infection; however, it can be prevented. By visiting clinics to be vaccinated before going to a high risk rabies exposure as mentioned in the study that the vaccine can provide at least one year immune memory (5), and can be helpful to prevent rabies infection. The virus can sometimes be taken lightly, but if not treated quickly, it can result to death. Fortunately many people are already aware of the risk of being infected of rabies, and many people already know the vaccines that had to be taken to avoid being infected. This information is very useful to humans because it gives us useful information and ideas on how to prevent rabies infection and what precaution can be done to minimize the probability of getting rabies. It also gives us idea on how many people get the virus and where they mostly occur.

The studies did not mention on how we can avoid being bite, scratch, or lick by the infected animals in the first place. They did not mention if there are techniques that can be done to avoid contact or places that we can avoid when visiting other countries that are at risk for rabies infection. It wasn't also mentioned if the vaccines that can be obtained from the clinic are free or how much it cost to be vaccinated.


Joseph L. Melnick, "Rabies", in AccessScience@McGraw-Hill, http://www.accessscience.com, DOI 10.1036/1097-8542.565400

XIAOWEI W, LOU J. TWO DYNAMIC MODELS ABOUT RABIES BETWEEN DOGS AND HUMAN. Journal of Biological Systems [serial online]. December 2008;16(4):519-529. Available from: Academic Search Complete, Ipswich, MA. Accessed March 31, 2010.\


Haider S. Rabies: old disease, new challenges. CMAJ: Canadian Medical Association Journal [serial online]. February 26, 2008;178(5):562-563. Available from: Academic Search Complete, Ipswich, MA. Accessed April 1, 2010.


Yung-Hsiang H, Hsing I. C. Acute respiratory distress syndrome associated with rabies. Pathology [serial online]. December 2008;40(6):647-650. Available from: Academic Search Complete, Ipswich, MA. Accessed April 1, 2010.


Khawplod P, Wilde H, Benjavongkulchai M, Sriaroon C, Chomchey P. Immunogenicity Study of Abbreviated Rabies Preexposure Vaccination Schedules. Journal of Travel Medicine [serial online]. May 2007;14(3):173-176. Available from: Academic Search Complete, Ipswich, MA. Accessed April 1, 2010.


Gautret P, Shaw M, Gazin P, et al. Rabies Postexposure Prophylaxis in Returned Injured Travelers From France, Australia, and New Zealand: A Retrospective Study. Journal of Travel Medicine [serial online]. January 2008;15(1):25-30. Available from: Academic Search Complete, Ipswich, MA. Accessed April 1, 2010.