Deliberate introduction of the European rabbit, Oryctolagus cuniculus, into Australia.

The European rabbit was brought to Australia as a companion animal by early settlers. It sometimes escaped, but failed to survive in the Australian bush. In 1879 wild rabbits were deliberately sent to Victoria to provide game for wealthy settlers to shoot. They soon spread all over Australia, except in the tropics, and became Australia's major animal pest. After careful testing in Australian wildlife and in humans, control by myxoma virus was introduced at various sites between 1937 and 1950, spreading all over the Murray-Darling Basin in 1950. Within one year mutations in the virus had led to slightly less virulence, and these continued for the next 50 years. In the early 21st Century testing viruses obtained from wild rabbits showed that the majority of these viruses were more virulent than the virus used to initiate the epidemic. In 1995 another virus specific for European rabbits, rabbit haemorrhagic disease virus, escaped from areas in which field trials were being carried out and spread around Australia. It was more successful than myxomatosis for rabbit control in arid regions.

Comparación del postoperatorio de dos colgajos en cirugía de terceros molares inferiores / Post operative comparison of two flap designs in lower third molar surgery

La cirugía de terceros molares constituye en la práctica de la cirugíaoral y maxilofacial, una de las intervenciones más realizadas. Las indicacionesson variadas, desde medidas profilácticas hasta grandes lesiones osteolíticas.Algunas de las consecuencias después de dicha intervención son;edema, trismus y dolor postoperatorio. En la técnica quirúrgica, el colgajocobra gran importancia a la hora de minimizar estas consecuencias. El objetivodel presente estudio es evaluar el postoperatorio de la cirugía de tercerosmolares mandibulares incluidos, utilizando un colgajo lineal en un ladoy un colgajo triangular en el otro lado del mismo paciente.Se realizó un estudio prospectivo en 15 pacientes de la Facultad de Odontologíade la Universidad Mayor. Se tomaron registros fotográficos estandarizadosy se midió la apertura bucal máxima pre-quirúrgica de cada paciente.Se registró el edema, la limitación de apertura bucal y el dolor a las 48horas y a los 7 días, además del tiempo intraoperatorio. Todos los datos fueronanalizados estadísticamente. No existen diferencias significativas en eledema, limitación de la apertura ni dolor al utilizar ambos colgajos. Tampocoexiste correlación entre el tiempo operatorio y las tres variables estudiadas.El postoperatorio de la cirugía de terceros molares mandibulares incluidos essimilar al utilizar un colgajo lineal o un colgajo triangular. El cirujano puedeoptar por uno o el otro indistintamente, según su preferencia(AU)

One of the most common procedures in the field of Oraland Maxillofacial Surgery is third molar surgery. From prophylacticmeasures to large osteolytic lesions, there are various indications.Some of the consequences of this procedure are; edema, trismusand postoperative pain. Flap design is an important feature ofsurgical technique that plays a vital role in minimizing theseconsequences. The objective of this study is a post operativeevaluation of included third molar jaw surgery using a linear flapon one side and a triangular flap on the other side of the samepatient.A prospective study of 15 patients from the Dentistry College at theMajor University was carried out. Before surgery standard photoswere taken and maximum oral opening was measured for eachpatient. The edema, maximum oral opening and pain were measured48 hours and 7 days after surgery. All of the data were analyzedstatistically. There are no significant differences in the edema, abilityto open the mouth or the level of pain using the two types of flap.There also is no correlation between the operation time and thethree variables studied.The postoperative edema, pain and trismus after included thirdmolar surgery are similar when using linear or triangular flap designs.The surgeon can choose one or the other indistinctly, accordingto his/her preference(AU)

Recent events and observations pertaining to smallpox virus destruction in 2002.

To destroy all remaining stocks of variola virus on or before 31 December 2002 seems an even more compelling goal today than it did in 1999, when the 52d World Health Assembly authorized temporary retention of remaining stocks to facilitate the possible development of (1) a more attenuated, less reactogenic smallpox vaccine and (2) an antiviral drug that could be used in treatment of patients with smallpox. We believe the deadline established in 1999 should be adhered to, given the potential outcomes of present research. Although verification that every country will have destroyed its stock of virus is impossible, it is reasonable to assume that the risk of a smallpox virus release would be diminished were the World Health Assembly to call on each country to destroy its stocks of smallpox virus and to state that any person, laboratory, or country found to have virus after date x would be guilty of a crime against humanity.

Adventures with poxviruses of vertebrates.

Because they were the largest of all viruses and could be visualised with a light microscope, the poxviruses were the first viruses to be intensively studied in the laboratory. It was clear from an early date that they caused important diseases of humans and their domestic animals, such as smallpox, cowpox, camelpox, sheeppox, fowlpox and goatpox. This essay recounts some of the early history of their recognition and classification and then expands on aspects of research on poxviruses in which the author has been involved. Studies on the best-known genus, Orthopoxvirus, relate to the use of infectious ectromelia of mice as a model for smallpox, embracing both experimental epidemiology and pathogenesis, studies on the genetics of vaccinia virus and the problem of non-genetic reactivation (previously termed 'transformation') and the campaign for the global eradication of smallpox. The other group of poxviruses described here, the genus Leporipoxvirus, came to prominence when the myxoma virus was used for the biological control of Australian wild rabbits. This provided a unique natural experiment on the coevolution of a virus and its host. Future research will include further studies of the many immunomodulatory genes found in all poxviruses of vertebrates, since these provide clues about the workings of the immune system and how viruses have evolved to evade it. Some of the many recombinant poxvirus constructs currently being studied may come into use as vaccines or for immunocontraception. A field that warrants study but will probably remain neglected is the natural history of skunkpox, raccoonpox, taterapox, yabapox, tanapox and other little-known poxviruses. A dismal prospect is the possible use of smallpox virus for bioterrorism.

Malaria control in Papua New Guinea in the Second World War: from disaster to successful prophylaxis and the dawn of DDT.

Australian forces were involved in warfare in hyperendemic areas of New Guinea from early 1942 until late 1945. Initially they were ill-prepared and suffered very heavy malaria casualties, even when not engaged in fighting. As a result measures were taken to make the supervision of personal protection (clothes, suppressive atebrin, repellent, mosquito nets) a matter for unit commanders rather than a medical problem. Malariologists were appointed and supervised Malaria Control Units, which were moved in with attacking troops, and Entomological Sections were established, which provided advice on vectors of malaria and other arthropod-borne diseases. In successive campaigns the casualties from malaria decreased substantially, especially after active operations in particular campaigns had ended, except in the Aitape-Wewak area, where field observations suggested that some strains of P. falciparum were resistant to the standard dose of suppressive atebrin. This was confirmed in experiments on human volunteers at a malaria research unit in Australia.

Malaria in New Guinea during the Second World War: the Land Headquarters Medical Research Unit.

In June 1943 arrangements were made to carry out experiments on malaria suppressive drugs on human volunteers in Cairns, in north Queensland, under the direction of Brigadier Neil Hamilton Fairley; early in 1944 the Land Headquarters Medical Research Unit was established to continue this work. Using 868 healthy volunteers and 317 infected soldiers and A. punctulatus mosquitoes flow in from New Guinea or bred locally, several suppressive drugs were tested. Doses of 10 grains of quinine daily failed to suppress New Guinea strains of P. falciparum and were only partially effective against P. vivax infections, whereas 100 mg of atebrin daily controlled symptoms of P. vivax infection and cured infections with most New Guinea strains of P. falciparum, however some strains of P. falciparum from Wewak were resistant to this dose, but were cured with double the daily dose.

Candidate viral diseases for elimination or eradication.

This article discusses the possibilities for elimination or eradication of four viral diseases--measles, hepatitis B, rubella and yellow fever.

Historical vignette: a life with poxviruses and publishers.

Although I started science investigating the physical anthropology of Australian aboriginals and then spent six years in the Australian Army during the 1939-45 war, largely working on malaria control, the poxviruses have been the focal point of my research--at the bench, in the field, on committees, and in front of my word processor. I have had a relatively short period as a scientist at the bench, just over twenty years out of the sixty years since I graduated. For the last thirty years the pipette has been replaced by the pen and the word processor, and contacts with publishers have become an important element in my life. My pilgrim's progress, from mousepox through myxomatosis to vaccinia and then smallpox, has been helped by what can only be described as good luck, coming in many guises. I have been fortunate in many ways; in my father and mother and the genes and family life they gave me; in my wife, who was an immense source of support until her death in 1995; in the people whom I met during the Second World War; and in my close association with three great scientists, Macfarlane Burnet, René Dubos, and Howard Florey. I had the good fortune to be appointed, as a young and inexperienced virologist, to one of the best research jobs in the world, as a professor in the Australian National University. I have been very lucky in having had the opportunity to exploit a series of scientific gold mines; in turn, malaria, during the War, then mousepox, an unexploited virus because its use was forbidden in the United States, then, after a brief flirtation with mycobacteria, myxomatosis, an unparalleled natural experiment of evolution in action, and finally the most impressive achievement in public health in world history, the global eradication of smallpox. My last job in the University before retirement provided me with the opportunity to do something about the most important problems confronting humankind: the degradation of the environment, driven by the explosion in human numbers and their ever-growing use of resources. Each of these activities has provided opportunities to establish and maintain close friendships with scientists all over the world.

Behavior of Na131I and meta(131I) iodobenzylguanidine (MIBG) in municipal sewerage.

Behavior of 131I activity in primary sludge at the Ann Arbor, Michigan, Municipal Waste Water Treatment Plant was studied in relation to known radioiodine therapy events at the University of Michigan Hospital complex. The principal compounds administered are Na131I, which has widespread use, and meta (131I) iodobenzylguanidine (MIBG), which is a compound unique to the University of Michigan, although labeled antibodies and other forms are also used in therapy and research. The objectives of the study were to determine the environmental fate of such discharges and to determine radiation exposures to workers and the public when sludges are incinerated. Approximately 17% of the MIBG activity administered in a therapy was found in the primary sludge, whereas only 1.1% of the Na131I was in sludge. When land applied, the short half life of 131I in the sludge presents few radiological health concerns; however, incineration, which is done in winter months, is assumed to release organically bound 131I to the atmosphere. Radiation doses due to incineration of sludge containing measured concentrations were calculated for a maximally exposed worker to be 1.7 microSv (0.17 mrem) of which 0.48 microSv (0.048 mrem) was due to a 2-d upset condition. For a more typically exposed worker, and a member of the public, the committed effective dose equivalents were 1.2 microSv (0.12 mrem) and 0.06 microSv (0.006 mrem), respectively, for a 22-wk incineration period with release of all radioiodine in the sludge. Transport time to the treatment plant for radioiodine was found to be much longer than that of normal sewage, possibly due to organic material in sewer lines that absorb iodine. The residence time of radioiodine in the sewer also appears to be longer than expected; whether other radioactive materials are held up the same way is not known but chemical form is surely a factor.

Radioactivity in municipal sewage and sludge.

OBJECTIVE: To determine the environmental consequences of discharges of radioactivity from a large medical research facility into municipal sewage, specifically 131I activity in sewage sludge, and the radiation exposures to workers and the public when sludges are incinerated. METHODS: The authors measured radioactivity levels in the sludge at the Ann Arbor, Michigan, Waste Water Treatment Plant following radioiodine treatments of two patients at the University of Michigan hospital complex and performed a series of calculations to estimate potential radiation doses due to releases of 131I from incineration of sewage sludge. RESULTS: Approximately 1.1% of the radioactive 131I administered therapeutically to patients was measured in the primary sludge. Radiation doses from incineration of sludge were calculated to be 0.048 millirem (mrem) for a worker during a period in which the incinerator filtration system failed, a condition that could be considered to represent maximum exposure conditions, for two nine-hour days. Calculated results for a more typically exposed worker (with the filtration system in operation and a 22-week period of incineration) yielded a committed effective dose equivalent of 0.066 mrem. If a worker were exposed to both conditions during the period of incineration, the dose was calculated to be 0.11 mrem. For a member of the public, the committed effective dose equivalent was calculated as 0.003 mrem for a 22-week incineration period. Exposures to both workers and the public were a very small fraction of a typical annual dose (about 100 mrem excluding radon, or 300 mrem with radon) due to natural background radiation. Transport time to the treatment plant for radioiodine was found to be much longer than that of a normal sewage, possibly due to absorption of iodine by organic material in the sewer lines. The residence time of radioiodine in the sewer also appears to be longer than expected. CONCLUSION: 131I in land-applied sludge presents few health concerns because sufficient decay occurs before it can reach the public however, incineration, which is done in winter months, directly releases the 131I from sewage sludge to the atmosphere, and even though exposures to both workers and the public were found to be considerably lower than 1% of natural background, incineration of sludge in a pathway for public exposure. Although 131I was readily measurable in sewage sludge, only about 1% of the radioione administered to patients was found in the sludge. The fate of the remaining radioactivity has not been established; some may be in secondary and tertiary residuals, but it is quite likely that most passed through the plant and was discharged in dilute concentrations in plant emissions. The behavior of radioiodine and other radioactive materials released into municipal seweage systems, such as those from large medical facilities, is not yet well understood.

Smallpox: emergence, global spread, and eradication.

Speculatively, it is suggested that variola virus, the cause of smallpox, evolved from an orthopoxvirus of animals of the central African rain forests (possibly now represented by Tatera poxvirus), some thousands of years ago, and first became established as a virus specific for human beings in the dense populations of the Nile valley perhaps five thousand years ago. By the end of the first millennium of the Christian era, it had spread to all the densely populated parts of the Eurasian continent and along the Mediterranean fringe of north Africa. It became established in Europe during the times of the Crusades. The great voyages of European colonization carried smallpox to the Americas and to Africa south of the Sahara. Transported across the Atlantic by Europeans and their African slaves, it played a major role in the conquest of Mexico and Peru and the European settlement of north America. Variolation, an effective preventive inoculation, was devised as early as the tenth century. In 1798 this practice was supplanted by Jenner's cowpox vaccine. In 1967, when the disease was still endemic in 31 countries and caused ten to fifteen million cases and about two million deaths annually, the World Health Organization embarked on a programme that was to see the disease eradicated globally just over ten years later, and the world was formally declared to be free of smallpox in May 1980. Smallpox is unique--a specifically human disease that emerged from some animal reservoir, spread to become a worldwide, severe and almost universal affliction, and finally underwent the reverse process to emergence, namely global eradication.

Wallace P. Rowe lecture. Poxviruses of laboratory animals.

Currently the subfamily Chordopoxvirinae, the poxviruses of vertebrates, is subdivided into eight genera, containing some 20-30 species; an inexact figure because the birdpox viruses have not yet been properly investigated taxonomically. I have discussed seven species belonging to three genera, all of which have caused infection and usually disease in mammals commonly used in the laboratory. The list could have been extended had I included chickens and swine as laboratory animals, for that would have meant that I would have spoken about the birdpox viruses and swinepox virus as well. However, I think I have said enough to remind you of the importance of this family of viruses to those of you concerned with laboratory animal medicine. I believe that Wally Rowe would have been interested, for every case I have described presents problems in the ecology of viruses, and like my mentor Macfarlane Burnet, Wally approached virology from an ecological point of view, whether he was thinking about the DNA provirus of retroviruses and the host chromosome, the pathogenesis of disease, or the spread of viruses in animal populations, all topics to which he made major contributions.