Interim Report

Team Number: 036
School Name: Cimarron High School
Area of Science:
Project Abstract: http://mode.lanl.k12.nm.us/97.98/abstracts/036.html
Interim Report: http://mode.lanl.k12.nm.us/97.98/interims/036.html
Final Report: http://mode.lanl.k12.nm.us/97.98/finalreports/036/finalreport.html

Our project is about the rabbit over population of New Zealand and the rabbit calicivirus, a disease which is being experimented with to control the population. We found out about this experiment through an article in Science Magazine. Through the article and some research we were able to find the e-mail address of Alvin Smith, a scientist who studied the virus in New Zealand. So far Mr. Smith has previded us with web sites, telephone numbers, and even some of his own pesonal experiences.

We are interested in the rabbit calicivirus because it could definately tell us a lot about how virusU are spread in the wild. This experiment could be usefull in preventing other virus outbreaks that could effect the human population. Studying the rabbit calicivirus would tell us much about the nature of virusU in the wild.

Where did rabbit calicivirus originate? Rabbit calicivirus disease was first reported in China in 1984 and soon after in Europe and Mexico. In only a few months, it killed sixty-four million farmed rabbits in Italy alone. The disease has now affected rabbits in over 40 countries on four continents. The origin of the virus is unknown but thought to be a more extreme form of a virus that has been circulating in rabbit populations for many years.

These reports alerted scientists to a possible new biological control for wild rabbits in Australia and New Zealand. The virus was introduced into quarantine at the CSIRO's Australian Animal Health Laboratory (AAHL) in Geelong for testing in 1991.

How has rabbit calicivirus spread overseas? Rabbit calicivirus spread to other countries overseas by humans trading in domestic rabbits. In Europe, the virus was first found in Italy in 1986 and has since spread to most of western Europe. The virus then spread to France in 1987, Spain and Switzerland in 1988, Germany in 1989, Denmark in1990, the Swedish island of Gotland in 1990, and southern Sweden in 1993.

RCD passed quickly from European domestic rabbits into the wild rabbit population. It is now recognized in wild rabbit populations throughout continental Europe and North Africa. The natural rate of spread among wild populations varies according to location.

Impact on wild rabbit populations: The initial outbreaks of rabbit calicivirus overseas occurred quickly over wide areas and its impact on rabbit populations was dramatic. Rabbit calicivirus can cause deaths of about 95% among adult rabbits. Similar impacts on rabbit numbers have been seen in Australia.

In Europe, the disease appears to follow a two-year cycle. Young rabbits up to eight weeks old which come into contact with the virus do not die from the disease, but become immune. They survive to become the breeding population in the following year. The immunity to the virus can be spread from parents to offspring, but they do not last. Within a few weeks the offspring may develope the virus.

The beginning of rabbit calicivirus in Australia: In 1989 Australian authorities discovered the potential for rabbit calicivirus as a biological control for the country's worst pest.

The Australian Agricultural Council and the former Council of Nature Conservation Ministers (CONCOM) recommended that rabbit calicivirus be examined as a possible biological control agent for rabbits. Later that year, CONCOM provided funds for a veterinary virologist from CSIRO's Australian Animal Health Laboratory (AAHL) to study the disease in Europe. As a result, a scientist from the South Australian Animal and Plant Control Commission began studying the ecology of rabbit calicivirus.

Those preliminary studies led to an investigation of rabbit calicivirus at AAHL. The laboratory there provides a safe environment for these tests to be preformed without the danger of exposing the virus to the outside world.

Laboratory tests at CSIRO's Australian Animal Health Laboratory: The three-year laboratory project began in July 1991. The rabbit calicivirus was imported from the Czech Federal Republic to AAHL in 1991. Before they began research on the virus, the AAHL performed many screening tests to check for other dangerous organisms that may have contaminated the virus. Rabbit calicivirus for experimental use was taken from the livers of infected rabbits because it can not be grown in cell culture.

Research began after a small breeding colony of wild rabbits was established at AAHL. The main parts of the project were to develop tests for the virus and determine if the virus affects rabbits of all ages in the same way; had the virus already infected wild rabbits in Australia and New Zealand and provided immunity; are other wildlife and domestic animals suseptible to the virus.

The laboratory trials showed that rabbit calicivirus is highly infectious to rabbits and kills laboratory and wild rabbits quickly. Twenty-four hours after infection, the rabbits appear depressed and their temperature rises. The rabbits die thirty to forty hours after infection, from respiratory and heart failure. Examination after death of the rabbits showed enlarged spleens and liver damage. Bleeding was not a feature. This proved that the former name, rabbit haemorrhagic disease (RHD), was wrong.

Other results included rabbits up to five to eight weeks old are less vulnerable to the virus than adult rabbits, which is consistent with European reports. However, the survivors gave off enough virus to kill adult rabbits. There was no evidence that Australian and New Zealand rabbits have had any prior exposure to any viruses similar to rabbit calicivirus. This means they are unlikely to be immune to the virus. Some tests were developed for detecting rabbit calicivirus. These tests could be used to watch the spread of the infection and to calculate the number of rabbits with immunity to the disease.

Non-target species testing: For a biological control virus to be approved for release in Australia, it must be shown that it does not infect non-target species. Overseas reports claim rabbit calicivirus virus is so specific that only European rabbits are susceptible. Rabbit calicivirus disease is now in 40 countries, on four continents and was first discovered over a decade ago. During that time it has been in contact with a large number of other species, including humans. There are no reports of the virus affecting anything but European rabbits.

A test was performed on 33 different species of domestic and wild animals. None of the 33 species tested were infected, or affected, by the virus.

Field trials with rabbit calicivirus: When research at AAHL on rabbit calicivirus was completed, scientists concluded that the virus may be a safe and effective biological control virus. A workshop to discuss the current knowledge of the virus was held in September 1993. The workshop was organised by the Bureau of Resource Sciences (BRS) and CSIRO with support from the New Zealand government. Many Australian and New Zealand agencies were represented at the workshop including the RSPCA and the New Zealand NSPCA, ANZFAS, and farmer organisations.

The workshop produced a set of recommendations on research and funding. Plans to try rabbit calicivirus in a natural environment, under quarantine conditions, were supported by the participants. Wardang Island.

Tests under quarentine are still being conducted. Some scientists support the idea of using the rabbit calicivirus as a form of biological population controll. OtherUs disagree, and they say that it would be too dangerous to release into the environment. Test results are varied and do not prove anything one way or the other. Desputes continue over the reliabilty of the virus.

For our project we plan to predict and graph the population of the different rabbit populations of New Zealand each year for the next ten years. We will find the rate of rabbits effected by the virus, the natural birth and death rate of rabbits, the populations for the past two years, and with this information we will calculate a formula. We are considering using fortran 90 or a new simulation program called stella. We have yet to have resarched this program but it is supposed to be designed for formulating populations and such.

We think our projectis going to be very interesting because viral expiraments can drastically effect populations. We cannot wait to see the outcome of our studies and our final project. We are anxious to compete in the New Mexico Supercomputing Challenge.

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New Mexico High School Supercomputing Challenge