Myxomatosis, Infectious
Myxoma virus
Population Control
Rabbits
Insect Vectors
Virulence
Role of the myxoma virus soluble CC-chemokine inhibitor glycoprotein, M-T1, during myxoma virus pathogenesis. (1/59)
Myxoma virus is a poxvirus that causes a virulent systemic disease called myxomatosis in European rabbits. Like many poxviruses, myxoma virus encodes a variety of secreted proteins that subvert the antiviral activities of host cytokines. It was recently demonstrated that the myxoma virus M-T1 glycoprotein is a member of a large poxvirus family of secreted proteins that bind CC-chemokines and inhibit their chemoattractant activities in vitro. To determine the biological role of M-T1 in contributing to myxoma virus virulence, we constructed a recombinant M-T1-deletion mutant virus that was defective in M-T1 expression. Here, we demonstrate that M-T1 is expressed continuously during the course of myxoma virus infection as a highly stable 43-kDa glycoprotein and is dispensable for virus replication in vitro. Deletion of M-T1 had no significant effects on disease progression or in the overall mortality rate of infected European rabbits but heightened the localized cellular inflammation in primary tissue sites during the initial 2 to 3 days of infection. In the absence of M-T1 expression, deep dermal tissues surrounding the primary site of virus inoculation showed a dramatic increase in infiltrating leukocytes, particularly monocytes/macrophages, but these phagocytes remained relatively ineffective at clearing virus infection, likely due to the concerted properties of other secreted myxoma virus proteins. We conclude that M-T1 inhibits the chemotactic signals required for the influx of monocytes/macrophages during the acute-phase response of myxoma virus infection in vivo, as predicted by its ability to bind and inhibit CC-chemokines in vitro. (+info)Development of an ELISA for detection of myxoma virus-specific rabbit antibodies: test evaluation for diagnostic applications on vaccinated and wild rabbit sera. (2/59)
An enzyme-linked immunosorbent assay (ELISA) was developed and compared with 2 reference diagnostic tests (indirect immunofluorescence [IF] and complement fixation) to detect myxoma virus-specific antibodies in sera from 50 rabbits experimentally vaccinated with an attenuated strain of myxoma virus or with a Shope fibroma virus. The ELISA was highly specific (100% specificity) and sensitive (100%, 21 days after homologous vaccination). In a comparison of the ELISA with the IF test in 128 wild rabbits from France, discrepant results were obtained in only 11 (8.6%) animals, which were positive with the ELISA and negative with the IF test. The higher sensitivity and the good specificity of the ELISA was confirmed in a serologic survey of 118 rabbits from 2 Kerguelen (Indian Ocean) islands, where the prevalence of myxomatosis varied considerably. The ELISA is an alternative serologic test for diagnosis, vaccine evaluation, and seroepidemiologic surveys of myxomatosis. (+info)Myxomatosis: passive immunity in the offspring of immune rabbits (Oryctolagus cuniculus) infested with fleas (Spilopsyllus cuniculi Dale) and exposed to myxoma virus. (3/59)
Kittens with maternal antibodies to myxoma virus, the offspring of rabbits which had recovered from myxomatosis, were exposed to fleas contaminated with myxoma virus and/or contact with infected rabbits from birth. All kittens died or became infected before 8 weeks of age. When compared with adult animals similarly infected the kittens showed no advantage in terms of survival time or recovery rate attributable to maternal antibodies. Flea transmission of virus was found more effective than contact transmissions. (+info)Role of the C-terminal RDEL motif of the myxoma virus M-T4 protein in terms of apoptosis regulation and viral pathogenesis. (4/59)
The purpose of this study was to investigate the significance of the C-terminal RDEL motif of the myxoma virus M-T4 protein in terms of apoptosis regulation and role in viral virulence. To accomplish this, a recombinant myxoma virus was created in which the C-terminal RDEL motif of M-T4 was deleted and a selectable marker (Ecogpt) was inserted immediately downstream. We hypothesized that removal of the RDEL motif from M-T4 would alter the subcellular localization of the protein and provide insight into its antiapoptotic role. Surprisingly, removal of the RDEL motif from M-T4 did not affect localization of the protein within the endoplasmic reticulum (ER), but it did reduce the stability of the mutant protein. Pulse-chase immunoprecipitation and endoglycosidase H analysis coupled with confocal fluorescent light microscopy demonstrated that the M-T4 RDEL(-) mutant protein is retained in the ER like wildtype M-T4 and suggests that the C-terminal RDEL motif is not the sole determinant for M-T4 localization to the ER. Infection of cultured rabbit lymphocytes with the M-T4 RDEL(-) mutant virus results in an intermediate apoptosis phenotype compared with the wildtype and M-T4 knockout mutant viruses. A novel myxomatosis phenotype was observed in European rabbits when infected with the recombinant M-T4 RDEL(-) mutant virus. Rabbits infected with the M-T4 RDEL(-) virus on day 9 postinfection exhibited an exacerbated edematous and inflammatory response at secondary sites of infections, particularly the ears. Our results indicate that the C-terminal RDEL motif may not be solely responsible for retention of M-T4 to the ER and that M-T4 may have a dual function in protecting infected lymphocytes from apoptosis and in modulating the inflammatory response to virus infection. (+info)Myxomatosis: the virulence of field strains of myxoma virus in a population of wild rabbits (Oryctolagus cuniculus L.) with high resistance to myxomatosis. (5/59)
The virulence of field strains of myxoma virus is increasing in the Mallee region of Victoria where the resistance of the rabbit to myxomatosis is high. This suggests that the climax association will be a moderately severe disease. (+info)The differential transmissibility of Myxoma virus strains of differing virulence grades by the rabbit flea Spilopsyllus cuniculi (Dale). (6/59)
Laboratory studies showed that few rabbit fleas (Spilopsyllus cuniculi (Dale)) transmitted myxomatosis after removal from wild rabbits (Oryctolagus cuniculus (L) that had been infected for fever than 10-12 days, irrespective of the virulence of the myxoma virus strain involved. Rabbits infected with fully virulent (Grade I) strains died within 10-15 days and few fleas from these hosts became infective; averaging all the samples takem. 12% of the fleas were infective. Also, few fleas acquired infectivity on individual rabbits which covered from infection with attenuated strains; the mean was 8% infective. Rabbits which died between 17 and 44 days after infection had higher proportions of infective fleas at all sampling times; the mean was 42% infective. Male and female fleas transmitted virus with equal efficiency. For rabbits infected with any of the attenuated virus strains the mean percentage of infective fleas was inversely related to the survival time of the host. Rabbits infected with moderately attenuated strains (Grades IIIA and IIIB) had, on average, the highest proportion of infective fleas; hence such strains have a selective advantage and have become predominant under natural conditions in Britain. The changes that might occur if there is an increase in host resistance to myxomatosis are discussed. (+info)Horizontal transmissible protection against myxomatosis and rabbit hemorrhagic disease by using a recombinant myxoma virus. (7/59)
We have developed a new strategy for immunization of wild rabbit populations against myxomatosis and rabbit hemorrhagic disease (RHD) that uses recombinant viruses based on a naturally attenuated field strain of myxoma virus (MV). The recombinant viruses expressed the RHDV major capsid protein (VP60) including a linear epitope tag from the transmissible gastroenteritis virus (TGEV) nucleoprotein. Following inoculation, the recombinant viruses induced specific antibody responses against MV, RHDV, and the TGEV tag. Immunization of wild rabbits by the subcutaneous and oral routes conferred protection against virulent RHDV and MV challenges. The recombinant viruses showed a limited horizontal transmission capacity, either by direct contact or in a flea-mediated process, promoting immunization of contact uninoculated animals. (+info)Coevolution of host and virus: the pathogenesis of virulent and attenuated strains of myxoma virus in resistant and susceptible European rabbits. (8/59)
Myxoma virus was introduced into the European rabbit population of Australia in 1950. Although the virus was initially highly lethal in rabbits, there was rapid selection for less virulent strains of virus and innately resistant rabbits. To investigate the basis of resistance to myxoma virus, we have compared the pathogensis of the virulent strain of myxoma virus originally released into Australia and an attenuated, naturally derived field strain of myxoma virus. This was done in laboratory rabbits, which have not been selected for resistance, and in wild rabbits that have developed significant resistance. Wild rabbits were able to recover from infection with virus that was always lethal in laboratory rabbits. Laboratory rabbits were able to control and recover from infection with attenuated virus. This virus caused a trivial disease in wild rabbits. There was little difference between laboratory and wild rabbits in titers of either virulent or attenuated virus in the skin at the inoculation site. However, resistant wild rabbits had a 10- to 100-fold lower titer of virulent virus within the lymph node draining the inoculation site and controlled virus replication in tissues distal to the draining lymph node. Replication of virus in lymphocytes or fibroblasts cultured from wild and laboratory rabbits demonstrated that resistance was not due to altered cellular permissivity for replication. Neutralizing antibodies were present in both susceptible and resistant rabbits, suggesting that these have no significant role in resistance. We hypothesise that resistance is due to an enhanced innate immune response that allows the rabbit to mount an effective cellular immune response. (+info)Myxomatosis, Infectious: A viral disease that primarily affects rabbits and hares. It is caused by the Myxoma virus, which belongs to the Poxviridae family. The disease is transmitted through direct contact with infected rabbits or through insect vectors such as mosquitoes and fleas.
The initial symptoms of myxomatosis include swelling of the eyelids, ears, and genital region. As the disease progresses, the rabbit may develop a high fever, difficulty breathing, and a bloody discharge from the nose and eyes. In severe cases, the rabbit may become blind, lose appetite, and become lethargic.
Myxomatosis is highly contagious and often fatal in wild rabbits, with mortality rates reaching up to 99%. However, domestic rabbits that have been vaccinated against the disease are generally resistant to infection. There is no specific treatment for myxomatosis, and efforts to control the spread of the disease typically focus on preventing transmission through insect vectors and limiting contact between infected and uninfected rabbits.
Myxoma virus (MYXV) is a member of the Poxviridae family, specifically in the Leporipoxvirus genus. It is a double-stranded DNA virus that naturally infects European rabbits (Oryctolagus cuniculus) and causes a fatal disease called myxomatosis. The virus is transmitted through insect vectors such as mosquitoes and fleas, and it replicates in the cytoplasm of infected cells.
Myxoma virus has been studied extensively as a model organism for viral pathogenesis and host-pathogen interactions. It has also been explored as a potential oncolytic virus for cancer therapy due to its ability to selectively infect and kill certain types of cancer cells while leaving normal cells unharmed. However, it is important to note that the use of Myxoma virus in humans is still experimental and requires further research and development before it can be considered safe and effective for therapeutic purposes.
Siphonaptera is the scientific order that includes fleas. Fleas are small, wingless insects with laterally compressed bodies and strong legs adapted for jumping. They are external parasites, living by hematophagy off the blood of mammals and birds. Fleas can be a nuisance to their hosts, and some people and animals have allergic reactions to flea saliva. Fleas can also transmit diseases, such as bubonic plague and murine typhus, and parasites like tapeworms.
"Population control" is not a term that is typically used in medical definitions. However, it is a concept that is often discussed in the context of public health and societal planning. In this context, population control refers to the practices and policies aimed at managing the size and growth rate of a population, with the goal of achieving a sustainable balance between population size and available resources.
Population control measures may include:
1. Family planning programs that provide access to contraception and education about reproductive health.
2. Public health initiatives that address maternal and child health, infectious diseases, and other factors that affect fertility rates.
3. Social and economic policies that promote gender equality, education, and economic opportunities for women, who often have a disproportionate impact on fertility rates.
4. In some cases, more coercive measures such as forced sterilization or abortion, which are widely considered to be unethical and violations of human rights.
It's important to note that population control is a complex and controversial issue, with many different perspectives and approaches. While some argue that managing population growth is essential for achieving sustainable development and reducing poverty, others argue that it is a violation of individual freedoms and human rights.
Poxviridae infections refer to diseases caused by the Poxviridae family of viruses, which are large, complex viruses with a double-stranded DNA genome. This family includes several pathogens that can infect humans, such as Variola virus (which causes smallpox), Vaccinia virus (used in the smallpox vaccine and can rarely cause infection), Monkeypox virus, and Cowpox virus.
These viruses typically cause skin lesions or pocks, hence the name "Poxviridae." The severity of the disease can vary depending on the specific virus and the immune status of the host. Smallpox, once a major global health threat, was declared eradicated by the World Health Organization in 1980 thanks to a successful vaccination campaign. However, other Poxviridae infections continue to pose public health concerns, particularly in regions with lower vaccination rates and where animal reservoirs exist.
I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.
However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.
Insect vectors are insects that transmit disease-causing pathogens (such as viruses, bacteria, parasites) from one host to another. They do this while feeding on the host's blood or tissues. The insects themselves are not infected by the pathogen but act as mechanical carriers that pass it on during their bite. Examples of diseases spread by insect vectors include malaria (transmitted by mosquitoes), Lyme disease (transmitted by ticks), and plague (transmitted by fleas). Proper prevention measures, such as using insect repellent and reducing standing water where mosquitoes breed, can help reduce the risk of contracting these diseases.
Virulence, in the context of medicine and microbiology, refers to the degree or severity of damage or harm that a pathogen (like a bacterium, virus, fungus, or parasite) can cause to its host. It is often associated with the ability of the pathogen to invade and damage host tissues, evade or suppress the host's immune response, replicate within the host, and spread between hosts.
Virulence factors are the specific components or mechanisms that contribute to a pathogen's virulence, such as toxins, enzymes, adhesins, and capsules. These factors enable the pathogen to establish an infection, cause tissue damage, and facilitate its transmission between hosts. The overall virulence of a pathogen can be influenced by various factors, including host susceptibility, environmental conditions, and the specific strain or species of the pathogen.
I apologize for any confusion, but "Australia" is not a medical term or concept. It is the world's largest island and smallest continent, located in the Southern Hemisphere, surrounded by the Pacific and Indian Oceans. It is composed of many diverse ecosystems, including deserts, rainforests, and coastal areas, and is home to a wide variety of unique plant and animal species.
If you have any questions related to medical terminology or health-related topics, I would be happy to try and help answer them for you!