scholarly journals Koala Retrovirus Diversity, Transmissibility, and Disease Associations

2020 ◽  
Author(s):  
HaoQiang Zheng ◽  
Yi Pan ◽  
Shaohua Tang ◽  
Geoffrey W. Pye ◽  
Cynthia K Stadler ◽  
...  

Abstract BackgroundKoalas are infected with the koala retrovirus (KoRV) that exists as exogenous or endogenous viruses. KoRV is genetically diverse with co-infection with up to ten envelope subtypes (A-J) possible; KoRV-A is the prototype endogenous form. KoRV-B, first found in a small number of koalas with an increased leukemia prevalence at one US zoo, has been associated with other cancers and increased chlamydial disease. To better understand the molecular epidemiology of KoRV variants and the effect of increased viral loads (VLs) on transmissibility and pathogenicity we developed subtype-specific quantitative PCR (qPCR) assays and tested blood and tissue samples from koalas at US zoos (n=78), two Australian zoos (n=27) and wild-caught (n=21) in Australia. We analyzed PCR results with available clinical, demographic, and pedigree data.ResultsAll koalas were KoRV-A-infected. A small number of koalas (10.3%) at one US zoo were also infected with non-A subtypes, while a higher non-A subtype prevalence (59.3%) was found in koalas at Australian zoos. Wild koalas from one location were only infected with KoRV-A. We observed a significant association of infection and plasma VLs of non-A subtypes in koalas that died of leukemia/lymphoma and other neoplasias and report cancer diagnoses in KoRV-A-positive animals. Infection and VLs of non-A subtypes was not associated with age or sex. Transmission of non-A subtypes occurred from dam-to-offspring and likely following adult-to-adult contact, but associations with contact type were not evaluated. Brief antiretroviral treatment of one leukemic koala infected with high plasma levels of KoRV-A, -B, and -F did not affect VL or disease progression. ConclusionsOur results show a significant association of non-A KoRV infection and plasma VLs with leukemia and other cancers. Although we confirm dam-to-offspring transmission of these variants, we also show other routes are possible. Our validated qPCR assays will be useful to further understand KoRV epidemiology and its zoonotic transmission potential for humans exposed to koalas because KoRV can infect human cells.

Retrovirology ◽  
2020 ◽  
Vol 17 (1) ◽  
Author(s):  
HaoQiang Zheng ◽  
Yi Pan ◽  
Shaohua Tang ◽  
Geoffrey W. Pye ◽  
Cynthia K. Stadler ◽  
...  

Abstract Background Koalas are infected with the koala retrovirus (KoRV) that exists as exogenous or endogenous viruses. KoRV is genetically diverse with co-infection with up to ten envelope subtypes (A-J) possible; KoRV-A is the prototype endogenous form. KoRV-B, first found in a small number of koalas with an increased leukemia prevalence at one US zoo, has been associated with other cancers and increased chlamydial disease. To better understand the molecular epidemiology of KoRV variants and the effect of increased viral loads (VLs) on transmissibility and pathogenicity we developed subtype-specific quantitative PCR (qPCR) assays and tested blood and tissue samples from koalas at US zoos (n = 78), two Australian zoos (n = 27) and wild-caught (n = 21) in Australia. We analyzed PCR results with available clinical, demographic, and pedigree data. Results All koalas were KoRV-A-infected. A small number of koalas (10.3%) at one US zoo were also infected with non-A subtypes, while a higher non-A subtype prevalence (59.3%) was found in koalas at Australian zoos. Wild koalas from one location were only infected with KoRV-A. We observed a significant association of infection and plasma VLs of non-A subtypes in koalas that died of leukemia/lymphoma and other neoplasias and report cancer diagnoses in KoRV-A-positive animals. Infection and VLs of non-A subtypes was not associated with age or sex. Transmission of non-A subtypes occurred from dam-to-offspring and likely following adult-to-adult contact, but associations with contact type were not evaluated. Brief antiretroviral treatment of one leukemic koala infected with high plasma levels of KoRV-A, -B, and -F did not affect VL or disease progression. Conclusions Our results show a significant association of non-A KoRV infection and plasma VLs with leukemia and other cancers. Although we confirm dam-to-offspring transmission of these variants, we also show other routes are possible. Our validated qPCR assays will be useful to further understand KoRV epidemiology and its zoonotic transmission potential for humans exposed to koalas because KoRV can infect human cells.


2020 ◽  
Author(s):  
HaoQiang Zheng ◽  
Yi Pan ◽  
Shaohua Tang ◽  
Geoffrey W. Pye ◽  
Cynthia K Stadler ◽  
...  

Abstract Background Koalas are infected with the koala retrovirus (KoRV) that exists as exogenous or endogenous viruses. KoRV is genetically diverse with co-infection with up to ten envelope subtypes (A-J) possible; KoRV-A is the prototype endogenous form. KoRV-B, first found in a small number of koalas with an increased leukemia prevalence at one US zoo, has been associated with other cancers and increased chlamydial disease. To better understand the molecular epidemiology of KoRV variants and the effect of increased viral loads (VLs) on transmissibility and pathogenicity we developed subtype-specific quantitative PCR (qPCR) assays and tested blood and tissue samples from koalas at US zoos (n=78), two Australian zoos (n=27) and wild-caught (n=21) in Australia. We analyzed PCR results with available clinical, demographic, and pedigree data. Results All koalas were KoRV-A-infected. A small number of koalas (10.3%) at one US zoo were also infected with non-A subtypes, while a higher non-A subtype prevalence (59.3%) was found in koalas at Australian zoos. Wild koalas from one location were only infected with KoRV-A. We observed a significant association of infection and plasma VLs of non-A subtypes in koalas that died of leukemia/lymphoma and other neoplasias and report cancer diagnoses in KoRV-A-positive animals. Infection and VLs of non-A subtypes was not associated with age or sex. Transmission of non-A subtypes occurred from dam-to-offspring and likely following adult-to-adult contact, but associations with contact type were not evaluated. Brief antiretroviral treatment of one leukemic koala infected with high plasma levels of KoRV-A, -B, and -F did not affect VL or disease progression. Conclusions Our results show a significant association of non-A KoRV infection and plasma VLs with leukemia and other cancers. Although we confirm dam-to-offspring transmission of these variants, we also show other routes are possible. Our validated qPCR assays will be useful to further understand KoRV epidemiology and its zoonotic transmission potential for humans exposed to koalas because KoRV can infect human cells.


2020 ◽  
Vol 22 (1) ◽  
pp. 165
Author(s):  
Lucía Pérez-Roque ◽  
Elena Núñez-Gómez ◽  
Alicia Rodríguez-Barbero ◽  
Carmelo Bernabéu ◽  
José M. López-Novoa ◽  
...  

Preeclampsia is a pregnancy-specific disease of high prevalence characterized by the onset of hypertension, among other maternal or fetal signs. Its etiopathogenesis remains elusive, but it is widely accepted that abnormal placentation results in the release of soluble factors that cause the clinical manifestations of the disease. An increased level of soluble endoglin (sEng) in plasma has been proposed to be an early diagnostic and prognostic biomarker of this disease. A pathogenic function of sEng involving hypertension has also been reported in several animal models with high levels of plasma sEng not directly dependent on pregnancy. The aim of this work was to study the functional effect of high plasma levels of sEng in the pathophysiology of preeclampsia in a model of pregnant mice, in which the levels of sEng in the maternal blood during pregnancy replicate the conditions of human preeclampsia. Our results show that wild type pregnant mice carrying human sEng-expressing transgenic fetuses (fWT(hsEng+)) present high plasma levels of sEng with a timing profile similar to that of human preeclampsia. High plasma levels of human sEng (hsEng) are associated with hypertension, proteinuria, fetal growth restriction, and the release of soluble factors to maternal plasma. In addition, fWT(hsEng+) mice also present placental alterations comparable to those caused by the poor remodeling of the spiral arteries characteristic of preeclampsia. In vitro and ex vivo experiments, performed in a human trophoblast cell line and human placental explants, show that sEng interferes with trophoblast invasion and the associated pseudovasculogenesis, a process by which cytotrophoblasts switch from an epithelial to an endothelial phenotype, both events being related to remodeling of the spiral arteries. Our findings provide a novel and useful animal model for future research in preeclampsia and reveal a much more relevant role of sEng in preeclampsia than initially proposed.


Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1477
Author(s):  
Tamsyn Stephenson ◽  
Natasha Speight ◽  
Wai Yee Low ◽  
Lucy Woolford ◽  
Rick Tearle ◽  
...  

Koala retrovirus, a recent discovery in Australian koalas, is endogenised in 100% of northern koalas but has lower prevalence in southern populations, with lower proviral and viral loads, and an undetermined level of endogenisation. KoRV has been associated with lymphoid neoplasia, e.g., lymphoma. Recent studies have revealed high complexity in southern koala retroviral infections, with a need to clarify what constitutes positive and negative cases. This study aimed to define KoRV infection status in Mount Lofty Ranges koalas in South Australia using RNA-seq and proviral analysis (n = 216). The basis for positivity of KoRV was deemed the presence of central regions of the KoRV genome (gag 2, pol, env 1, and env 2) and based on this, 41% (89/216) koalas were positive, 57% (124/216) negative, and 2% inconclusive. These genes showed higher expression in lymph node tissue from KoRV positive koalas with lymphoma compared with other KoRV positive koalas, which showed lower, fragmented expression. Terminal regions (LTRs, partial gag, and partial env) were present in SA koalas regardless of KoRV status, with almost all (99.5%, 215/216) koalas positive for gag 1 by proviral PCR. Further investigation is needed to understand the differences in KoRV infection in southern koala populations.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hu Suk Lee ◽  
Vuong Nghia Bui ◽  
Duy Tung Dao ◽  
Ngoc Anh Bui ◽  
Thanh Duy Le ◽  
...  

Abstract Background African swine fever (ASF), caused by the ASF virus (ASFV), was first reported in Vietnam in 2019 and spread rapidly thereafter. Better insights into ASFV characteristics and early detection by surveillance could help control its spread. However, the pathogenicity and methods for early detection of ASFV isolates from Vietnam have not been established. Therefore, we investigated the pathogenicity of ASFV and explored alternative sampling methods for early detection. Results Ten pigs were intramuscularly inoculated with an ASFV strain from Vietnam (titer, 103.5 HAD50/mL), and their temperature, clinical signs, and virus excretion patterns were recorded. In addition, herd and environmental samples were collected daily. The pigs died 5–8 days-post-inoculation (dpi), and the incubation period was 3.7 ± 0.5 dpi. ASFV genome was first detected in the blood (2.2 ± 0.8) and then in rectal (3.1 ± 0.7), nasal (3.2 ± 0.4), and oral (3.6 ± 0.7 dpi) swab samples. ASFV was detected in oral fluid samples collected using a chewed rope from 3 dpi. The liver showed the highest viral loads, and ear tissue also exhibited high viral loads among 11 tissues obtained from dead pigs. Overall, ASFV from Vietnam was classified as peracute to acute form. The rope-based oral fluid collection method could be useful for early ASFV detection and allows successful ASF surveillance in large pig farms. Furthermore, ear tissue samples might be a simple alternative specimen for diagnosing ASF infection in dead pigs. Conclusions Our data provide valuable insights into the characteristics of a typical ASFV strain isolated in Vietnam and suggest an alternative, non-invasive specimen collection strategy for early detection.


2021 ◽  
Vol 118 (38) ◽  
pp. e2024021118
Author(s):  
Briony A. Joyce ◽  
Michaela D. J. Blyton ◽  
Stephen D. Johnston ◽  
Paul R. Young ◽  
Keith J. Chappell

Koala populations are currently in rapid decline across Australia, with infectious diseases being a contributing cause. The koala retrovirus (KoRV) is a gammaretrovirus present in both captive and wild koala colonies that presents an additional challenge for koala conservation in addition to habitat loss, climate change, and other factors. Currently, nine different subtypes (A to I) have been identified; however, KoRV genetic diversity analyses have been limited. KoRV is thought to be exogenously transmitted between individuals, with KoRV-A also being endogenous and transmitted through the germline. The mechanisms of exogenous KoRV transmission are yet to be extensively investigated. Here, deep sequencing was employed on 109 captive koalas of known pedigree, housed in two institutions from Southeast Queensland, to provide a detailed analysis of KoRV transmission dynamics and genetic diversity. The final dataset included 421 unique KoRV sequences, along with the finding of an additional subtype (KoRV-K). Our analysis suggests that exogenous transmission of KoRV occurs primarily between dam and joey, with evidence provided for multiple subtypes, including nonendogenized KoRV-A. No evidence of sexual transmission was observed, with mating partners found to share a similar number of sequences as unrelated koala pairs. Importantly, both distinct captive colonies showed similar trends. These findings indicate that breeding strategies or antiretroviral treatment of females could be employed as effective management approaches in combating KoRV transmission.


2003 ◽  
Vol 16 (5) ◽  
pp. 305-312 ◽  
Author(s):  
U.P. Kappes ◽  
U. Barta ◽  
U. Merkel ◽  
A. Balogh ◽  
P. Elsner

2010 ◽  
Vol 209 (1) ◽  
pp. 206-210 ◽  
Author(s):  
Yukihiko Momiyama ◽  
Reiko Ohmori ◽  
Nobukiyo Tanaka ◽  
Ryuichi Kato ◽  
Hiroaki Taniguchi ◽  
...  

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Alison B Kohan ◽  
Fei Wang ◽  
Qing Yang ◽  
Sarah Huesman ◽  
H. H Dong ◽  
...  

INTRODUCTION Apolipoprotein C-III (apoC-III), synthesized by the liver and intestine, is an inhibitor of LPL-mediated lipolysis and hepatic clearance of triglyceride-rich lipoproteins. ApoC-III overproduction is linked with hypertriglyceridemia and atherosclerosis. ApoC-III may also play an intracellular role in hepatic VLDL assembly/secretion. Little is known about the role of apoC-III in the intestine, although it is secreted on chylomicrons coincident with triglyceride absorption. HYPOTHESIS Given that overexpression of apoC-III results in high plasma triglyceride levels, we hypothesized that it might also stimulate intestinal triglyceride transport, thereby exacerbating plasma hypertriglyceridemia in human apoC-III transgenic (h-apoC-III tg) mice. METHODS 28-30 gram male h-apoC-III tg (on a C57BL/6J background) were fitted with both a mesenteric lymph cannula and a duodenal feeding tube, and received a continuous intraduodenal infusion of triglyceride (6 μmol of 3[H]-Triolein in 0.3ml of phosphate-buffered saline) for 6 hours with hourly lymph samples collected (n=11-12). At the end of the infusion period, luminal and mucosal contents and tissue samples were isolated. An advantage of this lymph fistula model is the ability to sample lymph continuously throughout the triglyceride infusion period while avoiding confounding effects of anesthesia and stomach emptying. RESULTS h-apoC-III tg mice had a decrease in lymph flow and a 43% reduction in lymphatic 3[H]-triglyceride transport compared to WT mice. The h-apoC-III tg mice had 10.0±2.3% of the total dose of 3[H]-triglyceride remaining in intestinal lumen; which was significantly higher than the 3.1±0.4% observed in WT mice. Thin layer chromatographic analysis of the luminal contents showed that h-apoC-III tg mice, as opposed to WT controls, had a significantly higher percentage of fatty acid. There were no significant differences in the luminal triglyceride, diglyceride, and monoglyceride composition between groups. CONCLUSION Our studies reveal a novel role for apoC-III in decreasing intestinal triglyceride transport distinct from its extracellular roles in plasma on lipoprotein lipase, and its intracellular role in hepatic VLDL synthesis and secretion.


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