Detection Of C Pecorum
As our understanding of both chlamydial infection and disease has progressed since 2012, so has the development of tools to detect C. pecorum and chlamydial disease in koalas. Progress has been made in understanding which samples should be tested and how both molecular and non-molecular techniques can contribute to pathogen and disease detection. Recognizing that non-invasive koala sampling, such as scat detection and testing, can be a low cost, non-disruptive survey method, effort has been put into testing whether C. pecorum detection in scat is comparable to direct urogenital swab sampling by quantitative PCR . In a small study, testing found a high level of concordance between paired scat and urogenital swab samples, although the same C. pecorum ompA genotype was not always found between samples from the same koala . Perhaps unsurprisingly, C. pecorum copy numbers were consistently higher from urogenital swab samples compared to paired scat samples . Overall, this data suggests that non-invasive koala sampling has lower C. pecorum sensitivity compared to samples taken directly from a koala. This difference should be kept in mind when comparing prevalence estimates generated from different sampling methods.
A Riddle Wrapped In A Mystery
How bad is chlamydia in humans? Consider that around one in 10 sexually active teenagers in the United States is already infected, said Dr. Toni Darville, chief of the division of pediatric infectious diseases at the University of North Carolina. Chlamydia is the most common sexually transmitted infection worldwide, with 131 million new cases reported each year.
Antibiotics exist, but they are not enough to solve the problem, Dr. Darville said. Thats because chlamydia is a stealth organism, producing few symptoms and often going undetected for years.
We can screen them all and treat them, but if you dont get all their partners and all their buddies at the other high schools, you have a big spring break party and before you know it everybodys infected again, Dr. Darville said.So they have this long-term chronic smoldering infection, and they dont even know it. And then when theyre 28 and theyre like, Oh, Im ready to have a baby, everythings a mess.
In 2019, Dr. Darville and her colleagues received a multiyear, $10.7 million grant from the National Institute of Allergy and Infectious Diseases to develop a vaccine. The ideal package would combine a chlamydia and gonorrhea vaccine with the HPV vaccine already given to most preteenagers. If we could combine those three, youd basically have a fertility anticancer vaccine, she said.
Chlamydial Disease And Host Response
Chlamydiosis is a well-characterized disease in koalas. In the last 10 years, two areas of research have made notable advancements in our understanding of chlamydial disease in koalas: disease progression over time and the koala immune response to infection. Based on the recognition that koala chlamydiosis research was lacking population-level, long-term disease studies , researchers followed koala populations over several years to investigate more complex questions related to disease progression. In addition, the release of the first complete koala genome , as well as specialized koala transcriptome datasets , have allowed for koala-specific immune targets to be specifically investigated. Together, these advances have provided the foundation to delve more deeply into chlamydial disease progression in koalas.
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Koalas Exposed To Double Whammy Health Threat
An AIDS-like virus plaguing Australias koala population is leaving them more vulnerable to chlamydia and other threatening health conditions, University of Queensland research has found.
One of UQs leading COVID-19 vaccine researchers, Associate Professor Keith Chappell, has discovered that the chlamydia epidemic plaguing endangered koala populations in Queensland and NSW is linked to a common virus that likely supresses koalas immune systems.
Dr Chappell and Dr Michaela Blyton, from UQs Australian Institute for Bioengineering and Nanotechnology and School of Chemistry and Molecular Biosciences, made this discovery after studying more than 150 koalas admitted to Currumbin Wildlife Hospital.
Dr Chappell said this study could have far reaching impacts and lead to better protective measures like breeding programs and new anti-viral medications.
We know Queensland and NSW koala populations are heavily impacted by chlamydia infections and a retrovirus, but until now a clear link between the two has not been conclusively established, Professor Chappell said.
Our research has found that the amount of retrovirus circulating within an animals blood was strongly associated with chlamydia and symptoms like cystitis and conjunctivitis, as well as overall poor health.
Its a double whammy for already-endangered koalas.
Dr Chappell said they found high levels of the virus increased a koalas risk of chlamydia by over 200% per cent.
Disease Associated With Korv And Host Response
Retroviruses, including Gammaretrovirus members, are the causative agents of certain types of cancers and immunosuppressive or immune-mediated diseases . In koalas, KoRV was originally identified because of its apparent link to leukemia and this association has been maintained over time . Additional links to immunosuppression, seen in associations between chlamydial disease rates and KoRV rates in koalas, have also been reported . While reports continue to emerge showing KoRV in association with cancers and immunosuppressive outcomes in koalas, the data to date are of a correlative nature, not yet showing clear causation. However, as studies progress, clues into possible disease mechanisms of KoRV in koalas continue to be suggested.
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Treatments For C Pecorum Antibiotics And Vaccines
Alternative antibiotics such as doxycycline, florfenicol and penicillin G have all been considered for chlamydial disease treatment in koalas. Doxycycline given at 5 mg/kg diluted 50:50 in sterile saline once a week for four weeks has been found to reverse the signs of clinical cystitis, eliminate wet bottom and clear C. pecorum infection in a small group of koalas . Florfenicol treatment at dosages tolerable in the field had limited success, with only 26% of treated koalas resolving their clinical signs and being released without further treatment, with another 32% requiring additional treatment with chloramphenicol to resolve their disease signs and the remaining animals failing to clinically improve . Finally, penicillin G did not make it out of in vitro testing, where cell culture testing found this antibiotic induced a chlamydial stress response in C. pecorum and was not bactericidal . Given these results, there is still a great need for alternatives to antibiotic treatment for chlamydial disease management in koalas.
Demonstration Of Freedom From Chlamydia Pecorum On Ki
The probability that the KI koala population is C. pecorum-free was estimated by collating qPCR results from the targeted survey and DEW koala program historical clinical data in a scenario tree modelling approach. The probability of freedom of a given year of surveillance i i) was calculated using the Bayesian approach from the probability of freedom from the prior year i1 i1) and the surveillance system sensitivity and specificity , reflecting the strength of the evidence collected during the year i:
Pi was then adjusted for the probability of introduction i) during the same year i:
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Australian Koalas Line Up For Chlamydia Vaccine In New Trial
A koala suffering from chlamydia, rescued from an area where urban development is encroaching on koala habitat, undergoes health assessments while under anaesthesia at Vineyard Veterinary Hospital, in Vineyard, Sydney, Australia, October 1, 2020. REUTERS/Loren Elliot/File Photo
MELBOURNE, Oct 16 – About 400 Australian koalas will be vaccinated against chlamydia as part of a trial that researchers say they hope could play a significant role in the longer-term survival of the animals.
Chlamydia, a sexually transmitted disease also found in humans, has spread widely among Australian koalas, affecting half the animals in some areas.
“It is a cruel disease that causes debilitating conjunctivitis, bladder infections and at times, infertility, Amber Gillett, Australia Zoo Wildlife Hospital Wildlife veterinarian and coordinator of research, said in a statement on Friday as the trial began.
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The bacterial disease, which can be spread from mothers to their newborns, can also cause blindness, researchers say.
The koalas will each receive one dose of the vaccine and will be microchipped before being released into the wild.
“While this vaccination will directly benefit each of the animals, the trial will also have a focus on the protection provided by vaccination,” said Peter Timms, professor of microbiology at the University of the Sunshine Coast, which is leading the trial.
Treatment For Korv Vaccines
Currently, there are no treatments available for KoRV in koalas. Antiretroviral drug therapies currently available for human retrovirus treatment require daily drug administration, a situation that is limiting for captive koala colonies and unfeasible in wild koala populations. As such, the field has turned to vaccine development as the best hope for a KoRV management strategy.
The first KoRV vaccine trials tested whether recombinant KoRV Env protein given to rats and goats could generate neutralizing antibodies . These studies determined that binding antibodies could be generated to the FPPR and MPER regions of the Env protein, however, only the antibodies to the MPER region were neutralizing . This lead to a small safety trial where three northern koalas were given a rKoRV-A Env vaccine . All three vaccinated koalas showed no signs of adverse reaction and the one koala that did not have detectable Env antibodies prior to vaccination was found to be generating Env antibodies post-vaccination . Subsequently, vaccination of six southern koalas also found no adverse vaccination effects, significant anti-KoRV antibody responses and decreases in KoRV circulating load post-vaccination . These promising pilot studies have established that vaccination for KoRV is safe in koalas and represents a promising avenue for KoRV management. The successes so far have paved the way for larger vaccine trials that are currently underway.
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Can Cats Get Stds
A-Yes, animals can suffer from venereal diseases, but this occurs much less frequently than among people. Pets that have been spayed and neutered obviously dont mate, so theres no need to worry about them passing on venereal diseases. Feline AIDS is a virus that in some ways resembles the human AIDS virus.
Chlamydia Pecorum Molecular Detection
Statistical analysis was performed using SPSS v.24 to determine significance based on sex, age and C. pecorum status . For continuous Chlamydia load variables, a Shapiro-Wilk test was performed to determine Gaussian distributions. For variables with normal distribution, an F-test was performed to determine equal variance prior to a two-way independent t-test. For non-parametric variables a Kruskal-Wallis H analysis was performed with post-hoc Mann-Whitney U test. Chi-squared analysis was performed to determine relationships and odds ratio between C. pecorum infection, sex, age and reproduction status.
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Advances In The Genetic Understanding Of Korv
Some of the most exciting and technically advanced work that has been done with KoRV in recent years relates to our understanding of this virus on a genetic level. In 2012, KoRV was considered a single virus while, by 2020, there are now nine subtypes recognized . Beyond investigating the diversity of this virus, work has also focused on understanding basic viral properties, understanding viral integration into the koala genome, expanding our knowledge of defective KoRV variations, and learning what other endogenous retroviruses in the koala that KoRV may interact with. Collectively, this body of work has not only advanced KoRV understanding but has added important information to our knowledge of retrovirology in general.
KoRV diversity detected from koalas, visualized by minimum spanning tree . Reference strains including Hanger et al. , Shojima et al. , Xu et al. and Xu et al. , Chappell et al. Sarker et al. and Quigley 2020 .
The biology of a typical Gammaretrovirus is well understood by virologists . Like all gammaretroviruses, KoRV is composed of a simple genome with long terminal repeats at each end of a linear single-stranded RNA genome containing three genes the group-specific antigen gene, the protease-polymerase gene and the envelope gene . To understand if KoRV behaves the same way as other gammaretroviruses during infection, studies have investigated specific properties of KoRV genes and proteins.
Origin Of C Pecorum In Koalas
Although records of koalas before and during early European settlement in Australia are sparse, there is a general belief that chlamydiosis has been a component of koalas natural history . However, recent molecular epidemiology investigations of C. pecorum across several animal hosts have introduced the hypothesis that at least some koala Chlamydia infections may be spill-over events from introduced domestic livestock. Both multilocus sequence typing and whole genome comparisons of C. pecorum have detected genetically similar strains between koalas and sheep . Additionally, two koalas from French Island, Victoria have now been found to be infected with C. pecorum strains more closely related to known cattle and pig livestock strains compared to known koala strains from the mainland . More epidemiological tracking is needed to clarify whether these apparent livestock/koala spill-over events are common and if these events are having an appreciable impact on koala disease. However, these findings do highlight that C. pecorum has a broad host range and the introduction of domestic livestock to Australia cannot be ruled out as a source of chlamydial infection for native animals like the koala.
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Prevalence Of C Pecorum Infection And Chlamydial Disease
An important area of koala chlamydial research that has received focused attention since 2012 has been the survey and characterization of C. pecorum infections and/or chlamydial disease in koalas across Australia . A review of C. pecorum positivity in koala populations before 2012 found rates from 0% C. pecorum detected up to 87%90% positivity in koala populations from QLD and VIC . Since that review, there have been 18 additional studies that have investigated some aspect of C. pecorum presence and/or chlamydial disease rates in koalas across the range . These studies have used a range of both established and novel C. pecorum detection and genotyping PCR assays .
Finally, the situation where koalas present with the classic signs of chlamydial disease, but with no detectable C. pecorum, should also be acknowledged. Cross-sectional studies that have evaluated both chlamydial infection and disease in the same animal routinely report individuals with disease signs clinically attributable to chlamydial disease but without C. pecorum being detected by molecular testing of samples . The definitive reason for these discrepancies is currently unknown, but theories to account for these differences include an alternative pathogen in koalas causing the same clinical signs , variation in organism shedding during the course of disease or the resolution of the C. pecorum infection before/without the resolution of clinical signs .
Climate Change Is Making The Problem Worse
The climate crisis has made Australia more vulnerable to devastating bushfires, such as those seen in 2019, as well as drought and heatwaves. Its also making koalas more susceptible to disease.
According to Australias leading scientific body, the Commonwealth Scientific and Industrial Research Organisation , the country has already warmed on average since 1910.
The Australian government report said when the marsupials are exposed to unusually stressful environmental conditions, including hot weather, drought, habitat loss and fragmentation, chlamydia spreads more quickly through their population.
Experts say they have witnessed similar rapid explosions of disease in the wild. Krockenberger said in his Gunnedah sample population, a series of heatwaves and droughts in 2009 and 2010 preceded a doubling of chlamydia cases.
Peter Timms, professor of microbiology at University of Sunshine Coast in Australia, said once koalas stress hormones rise due to environmental problems, infections often progress from a relatively minor problem to one that is more serious.
He said a combination of habitat loss and climate change is causing koalas to be chronically stressed, depressing their immune systems.
All that leads to poor chlamydia response. It gets them from low grade chlamydia infections to more serious disease, he said.
Thats what were doing to them. And were doing it on all fronts.
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Virus Puts Koalas At Greater Risk Of Chlamydia
“There is no question that koala retrovirus and chlamydia are connected, and we believe the retrovirus suppresses the koala’s immune system, making them more vulnerable to disease,” says Keith Chappell.
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An AIDS-like virus plaguing Australias koala population is leaving them more vulnerable to chlamydia and other threatening health conditions, a new study shows.
According to the findings, the chlamydia epidemic plaguing endangered koala populations is linked to a common virus that likely suppresses their immune systems.
Researchers made the discovery after studying more than 150 koalas admitted to Currumbin Wildlife Hospital. The study could lead to better protective measures like breeding programs and new anti-viral medications, says Keith Chappell, associate professor at the University of Queensland.
We know Queensland and NSW koala populations are heavily impacted by chlamydia infections and a retrovirus, but until now a clear link between the two has not been conclusively established, Chappell says.
Our research has found that the amount of retrovirus circulating within an animals blood was strongly associated with chlamydia and symptoms like cystitis and conjunctivitis, as well as overall poor health. Its a double whammy for already-endangered koalas.
Prevalence Of Korv In Koalas
As KoRV gained recognition as an important koala pathogen to investigate, surveys of koala populations from across Australia have included KoRV detection . Between 2012 and 2019, KoRV prevalence has been determined in 10 studies of Australian koalas and four studies of koalas in international zoos . As with C. pecorum detection, KoRV detection has relied on a range of PCR assays .
Early studies, before the range of KoRV subtypes were recognized, focused on detecting KoRV using a general pol gene assay . More recent studies have either combined KoRV pol gene pre-screening with specific KoRV-A and KoRV-B assays, have assayed directly for KoRV-A or have surveyed for all KoRV subtypes simultaneously by deep amplicon sequencing . These studies have found that northern koalas are always found to be infected with KoRV/KoRV-A while southern koala infection rates range from 0% to 100%, depending on the area .
Prevalence of koala retrovirus provirus infection reported in studies from 2012 to 2019. Grey ellipticals indicate the mapped area investigated, pie charts represent the KoRV positivity by subtype reported in n number of koalas tested. Details for each study can be found in Table .
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