Post by Terry S. Singeltary Sr. on Jul 8, 2023 9:30:42 GMT -6
4th International Chronic Wasting Disease Symposium 2023
17 DETECTION OF CHRONIC WASTING DISEASE PRIONS IN PROCESSED MEATS.
Rebeca Benavente1, Francisca Bravo1,2, Paulina Soto1,2, J. Hunter Reed3, Mitch Lockwood3, Rodrigo Morales1,2
1Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Santiago, Chile. 3Texas Parks and Wildlife, Austin, USA
Abstract
The zoonotic potential of chronic wasting disease (CWD) remains unknown. Currently, there are no known natural cases of CWD transmission to humans but increasing evidence suggests that the host range of CWD is not confined only to cervid species. Alarmingly, recent experimental evidence suggests that certain CWD isolates can induce disease in non-human primates. While the CDC strongly recommends determining CWD status in animals prior to consumption, this practice is voluntary. Consequently, it is plausible that a proportion of the cervid meat entering the human food chain may be contaminated with CWD. Of additional concern is that traditional diagnostic techniques used to detect CWD have relatively low sensitivity and are only approved for use in tissues other than those typically ingested by humans. In this study, we analyzed different processed meats derived from a pre-clinical, CWD-positive free-ranging elk. Products tested included filets, sausages, boneless steaks, burgers, ham steaks, seasoned chili meats, and spiced meats. CWD-prion presence in these products were assessed by PMCA using deer and elk substrates. Our results show positive prion detection in all products. To confirm the resilience of CWD-prions to traditional cooking methods, we grilled and boiled the meat products and evaluated them for any remnant PMCA seeding activity. Results confirmed the presence of CWD-prions in these meat products suggesting that infectious particles may still be available to people even after cooking. Our results strongly suggest ongoing human exposure to CWD-prions and raise significant concerns of zoonotic transmission through ingestion of CWD contaminated meat products.
***> Products tested included filets, sausages, boneless steaks, burgers, ham steaks, seasoned chili meats, and spiced meats.
***> CWD-prion presence in these products were assessed by PMCA using deer and elk substrates.
***> Our results show positive prion detection in all products.
***> Results confirmed the presence of CWD-prions in these meat products suggesting that infectious particles may still be available to people even after cooking.
***> Our results strongly suggest ongoing human exposure to CWD-prions and raise significant concerns of zoonotic transmission through ingestion of CWD contaminated meat products.
=====
9 Carrot plants as potential vectors for CWD transmission.
Paulina Soto1,2, Francisca Bravo-Risi1,2, Claudio Soto1, Rodrigo Morales1,2
1Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Santiago, Chile
Abstract
Chronic wasting disease is a prion disease affecting cervids captive and free-range. CWD is thought to be caused by indirect exposure to contaminated environments. Many studies have shown that infectious prions can enter the environment through saliva, feces, or urine from infected animals and decaying carcasses. However, we need to understand the specific contribution of this component to disease transmission events. Plants are logical environmental components to be evaluated since they grow in environments contaminated with CWD prions and are relevant for transmission. The main objective of this study is to characterize whether prions are transported to the roots and leaves of carrots, an edible plant commonly used in the human diet and as deer bait. We have grown carrot plants in CWD-infected soils. We harvested the carrots and separated them from the leaves. These materials were interrogated for their prion seeding activity using the PMCA. Infectivity was evaluated in mouse bioassays (intracerebral injections in Tg1536 mice). The PMCA analysis demonstrated CWD seeding activity in soils contaminated with CWD prions and in carrot plants (leaves and roots) grown on them. Bioassays showed that both plants and roots contained CWD prions sufficiently to induce disease. As expected, animals treated with prion-infected soils developed prion disease at shorter incubation periods (and complete attack rates) compared to plant components. We show that edible plant components can absorb prions from CWD-contaminated soils and transport them to their aerial parts. Our results indicate that edible plants could participate as vectors of CWD transmission.
***> We show that edible plant components can absorb prions from CWD-contaminated soils and transport them to their aerial parts.
***> Our results indicate that edible plants could participate as vectors of CWD transmission.
=====
15 Detection of CWD prions in plants collected from white-tailed deer farms
Francisca Bravo-Risi1,2, Paulina Soto1,2, Yumeng Huang1, Tracy A. Nichols3, Rodrigo Morales1,4
1Department of Neurology, The University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Doctorado en Ciencias con Mención en Materiales Funcionales, Santiago, Chile. 3Veterinary Services Cervid Health Program, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, USA. 4Centro Integrativo de Biologia y Quimica Aplicada (CIBQA), Universidad Bernardo O’Higgins, Santiago, Chile
Abstract
Chronic wasting disease (CWD) is a prion disease affecting captive and free-ranging cervids. Transmission of CWD is thought to occur by direct animal-to-animal contact and by exposure to contaminated environmental fomites. CWD-prions are spread into the environment through biological fluids, excreta, and decaying carcasses. Extensive studies demonstrate that soils adsorb infectious prions which can remain attached for extended periods. Accordingly, prion seeding activity has been detected in natural and experimental samples including mineral licks, water sources, and dust. Although, detection of prion in plants under experimental conditions was demonstrated, the role of plants in CWD spreading has been poorly explored. In the present study, we optimized the detection of CWD-prions in plants using the protein misfolding cyclic amplification (PMCA) technology. Specifically, we compared NaPTA pretreatments and direct spiking of the sample into the PMCA reactions. After achieving technical optimizations, we screened multiple plant specimens collected from white-tailed deer breeding facilities displaying variable CWD prevalence. Our results demonstrated that CWD-prion detection for plants was optimal when samples were pre-treated with a NaPTA PrPSc enriching procedure. Our screening results showed positive PMCA activity for specimens collected from the farm with the highest CWD prevalence. Plants from the same site were tested for infectivity in meadow voles, a co-existing animal species that feeds from grass plants. Although meadow voles were highly susceptible to CWD prions by intra-cerebral administration, ingestion of contaminated grass did not induce prion replication in these rodents. These findings further contribute to understand the role of plants in CWD-prion transmission.
=====
8 The chronic wasting disease agent from white-tailed deer is infectious to humanized mice after passage through raccoons
Eric Cassmann1, Xu Qi2, Qingzhong Kong2, Justin Greenlee1
1USDA ARS, Ames, USA. 2Case Western Reserve University, Cleveland, USA
Abstract
The aim of this study was to evaluate the zoonotic potential of the raccoon passaged chronic wasting disease (CWD) agent in humanized transgenic mice in comparison with the North American CWD agent from the original white-tailed deer (WTD) host. Pooled brain (GG96) from CWD positive white-tailed deer was used to intracranially inoculate two WTD and one raccoon. Brain homogenates (10% w/v) from the raccoon and the WTD were used to intracranially inoculate transgenic mice (Tg40h) expressing the methionine 129 human prion protein. Brains and spleens were collected from mice at experimental endpoints of clinical disease or approximately 700 days post-inoculation. Tissues were divided and homogenized or fixed in 10% buffered neutral formalin. Immunohistochemistry, enzyme immunoassay, and western blot were used to detect misfolded prion protein (PrPSc) in tissue. Tg40h mice inoculated with the raccoon passaged CWD agent from WTD exhibited a 100% (12/12) attack rate with an average incubation period of 605 days. PrPSc was detected in brain tissue by enzyme immunoassay with an average optical density of 3.6/4.0 for positive brains. PrPSc also was detected in brain tissue by western blot and immunohistochemistry. No PrPSc was detected in the spleens of mice inoculated with the raccoon passaged CWD agent. Humanized mice inoculated with the CWD agent from WTD did not have detectable PrPSc using conventional immunoassay techniques. These results demonstrated that the host range of the CWD agent from WTD was expanded in our experimental model after one passage through raccoons.
***> These results demonstrated that the host range of the CWD agent from WTD was expanded in our experimental model after one passage through raccoons.
=====
Transmission of prion infectivity from CWD-infected macaque tissues to rodent models demonstrates the zoonotic potential of chronic wasting disease.
Samia Hannaoui1,2, Ginny Cheng1,2, Wiebke Wemheuer3, Walter Schulz-Schaeffer3, Sabine Gilch1,2, Hermann Schatzl1,2 1University of Calgary, Calgary, Canada. 2Calgary Prion Research Unit, Calgary, Canada. 3Institute of Neuropathology, Medical Faculty, Saarland University, Homburg/Saar, Germany
Abstract
We provide evidence by transmission experiments to different transgenic mouse models and bank voles that Cynomolgus macaques inoculated via different routes with CWD-positive cervid tissues harbor infectious prions. We used tissue materials from macaques inoculated with CWD to inoculate transgenic mice overexpressing cervid PrPC followed by transmission into bank voles. We used RTQuIC, immunoblot and PET blot analysis to assess brains, spinal cords, and tissues of the gastrointestinal tract (GIT) for the presence of prions. Our results show that macaque materials induced clinical disease in transgenic mice with low attack rates. Clinical mice did not display PrPSc in immunoblot, but showed low-levels of prion seeding activity. Further transmission into bank voles led to a 100% attack rate with typical PrPSc signature in immunoblot, and high-level prion seeding activity in brain, spinal cord and GIT tissues. Second passage studies led to 100% attack rate in voles inoculated with brain, spinal cord and small intestine material from first round animals, with shortened survival times indicating adaptation in the new host. This shows that prions detected in GIT tissues are infectious and transmissible. Further passage to cervidized mice revealed transmission with a 100% attack rate. Our findings demonstrate that macaques, considered the best model for the zoonotic potential of prions, were infected upon CWD challenge, including the oral one. The disease manifested as atypical in macaques and initial transgenic mouse transmissions, but with infectivity present at all times, as unveiled in the bank vole model with an unusual tissue tropism.
***> Further passage to cervidized mice revealed transmission with a 100% attack rate.
***> Our findings demonstrate that macaques, considered the best model for the zoonotic potential of prions, were infected upon CWD challenge, including the oral one.
****> The disease manifested as atypical in macaques and initial transgenic mouse transmissions, but with infectivity present at all times, as unveiled in the bank vole model with an unusual tissue tropism.
***> Epidemiologic surveillance of prion disease among cervid hunters and people likely to have consumed venison contaminated with chronic wasting disease
=====
Efficient CWD-like transmission of splenic prions in cervidized transgenic mice: a probable diagnostic marker for CWD infection in humans
Xu Qi, Liuting Qing, Manuel Camacho, Ignazio Cali, Qingzhong Kong
Department of Pathology, Case Western Reserve University, Cleveland, USA
Abstract
Multiple in vitro CWD-seeded human PrP conversion experiments and some animal model studies indicate that the species barrier for CWD to human transmission can be overcome, but whether CWD prion can infect humans in real life remains controversial. The very limited understanding on the likely features of CWD infection in humans and the lack of a reliable marker for identification of acquired human CWD cases contribute to this uncertainty. We aim to stablish a reliable diagnostic marker for CWD infections in humans should they occur.
We identified a couple of prion-positive spleens in humanized transgenic mice inoculated with some CWD isolates. Such experimentally generated splenic “humanized” CWD prions (termed eHuCWDsp) appear indistinguishable from prions in the brain of sCJDMM1 patients on Western blot. We compared eHuCWDsp with prions in the spleen from humanized mice infected with sCJDMM1 (termed sCJDsp) by bioassays in cervidized or humanized transgenic mice. Significantly, we found that eHuCWDsp can efficiently infect not only the humanized mice but also cervidized transgenic mice, and cervidized mice infected by eHuCWDsp produced prions and brain pathology that are practically identical to those of CWD-infected cervidized mice. In contrast, sCJDsp, similar to prions from sCJDMM1 patient brains, is poorly transmissible in the cervidized mice.
Our data demonstrate that high transmissibility with CWD features of splenic prions in cervidized transgenic mice is unique to acquired human CWD prions, and it may serve as a reliable marker to identify the first acquired human CWD cases.
***> Such experimentally generated splenic “humanized” CWD prions (termed eHuCWDsp) appear indistinguishable from prions in the brain of sCJDMM1 patients on Western blot.
=====
Are stable and highly zoonotic cervid prion strains possible?
Manuel Camacho, Xu Qi, Liuting Qing, Sydney Smith, Jieji Hu, Wanyun Tao, Ignazio Cali, Qingzhong Kong Department of Pathology, Case Western Reserve University, Cleveland, USA
Abstract
Whether CWD prions can infect humans remains unclear despite the very substantial scale and long history of human exposure of CWD in many states or provinces of USA and Caada. Multiple in vitro conversion experiments and in vivo animal studies indicate that the CWD-to-human transmission barrier is not unbreakable. A major long-term public health concern on CWD zoonosis is the emergence of highly zoonotic CWD strains. We aim to address the question of whether highly zoonotic CWD strains are possible. We inoculated a few sCJD brain samples into cervidized transgenic mice (Tg12), which were intended as negative controls for bioassays of brain tissues from sCJD cases who had hunted or consumed venison from CWD-endemic states. Some of the Tg12 mice became infected, resulting in a “cervidized” CJD strain that we termed CJDElkPrP. CJDElkPrP was further examined by serial passages in humanized or cervidized mice. We observed 100% transmission of the original CJDElkPrP in transgenic mice expressing human PrP. We passaged CJDElkPrP two more times in the Tg12 mice. We found that such second and third passage CJDElkPrP prions retained 100% transmission rate in the humanized mice. In contrast, we and others found zero or poor transmission of natural elk CWD isolates in humanized mice, despite that the natural elk CWD isolates and CJDElkPrP share the same elk PrP sequence. Our data indicate that highly zoonotic cervid prion strains are not only possible but also can be stably maintained in cervids.
***> Our data indicate that highly zoonotic cervid prion strains are not only possible but also can be stably maintained in cervids.
snip=====END
I HAVE NOT READ ALL THESE, BUT THOUGHT SOME OF YOU MIGHT FIND THIS INTERESTING!
kind regards, terry
intcwdsympo.files.wordpress.com/2023/06/final-agenda-with-abstracts.pdf?force_download=true
17 DETECTION OF CHRONIC WASTING DISEASE PRIONS IN PROCESSED MEATS.
Rebeca Benavente1, Francisca Bravo1,2, Paulina Soto1,2, J. Hunter Reed3, Mitch Lockwood3, Rodrigo Morales1,2
1Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Santiago, Chile. 3Texas Parks and Wildlife, Austin, USA
Abstract
The zoonotic potential of chronic wasting disease (CWD) remains unknown. Currently, there are no known natural cases of CWD transmission to humans but increasing evidence suggests that the host range of CWD is not confined only to cervid species. Alarmingly, recent experimental evidence suggests that certain CWD isolates can induce disease in non-human primates. While the CDC strongly recommends determining CWD status in animals prior to consumption, this practice is voluntary. Consequently, it is plausible that a proportion of the cervid meat entering the human food chain may be contaminated with CWD. Of additional concern is that traditional diagnostic techniques used to detect CWD have relatively low sensitivity and are only approved for use in tissues other than those typically ingested by humans. In this study, we analyzed different processed meats derived from a pre-clinical, CWD-positive free-ranging elk. Products tested included filets, sausages, boneless steaks, burgers, ham steaks, seasoned chili meats, and spiced meats. CWD-prion presence in these products were assessed by PMCA using deer and elk substrates. Our results show positive prion detection in all products. To confirm the resilience of CWD-prions to traditional cooking methods, we grilled and boiled the meat products and evaluated them for any remnant PMCA seeding activity. Results confirmed the presence of CWD-prions in these meat products suggesting that infectious particles may still be available to people even after cooking. Our results strongly suggest ongoing human exposure to CWD-prions and raise significant concerns of zoonotic transmission through ingestion of CWD contaminated meat products.
***> Products tested included filets, sausages, boneless steaks, burgers, ham steaks, seasoned chili meats, and spiced meats.
***> CWD-prion presence in these products were assessed by PMCA using deer and elk substrates.
***> Our results show positive prion detection in all products.
***> Results confirmed the presence of CWD-prions in these meat products suggesting that infectious particles may still be available to people even after cooking.
***> Our results strongly suggest ongoing human exposure to CWD-prions and raise significant concerns of zoonotic transmission through ingestion of CWD contaminated meat products.
=====
9 Carrot plants as potential vectors for CWD transmission.
Paulina Soto1,2, Francisca Bravo-Risi1,2, Claudio Soto1, Rodrigo Morales1,2
1Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Santiago, Chile
Abstract
Chronic wasting disease is a prion disease affecting cervids captive and free-range. CWD is thought to be caused by indirect exposure to contaminated environments. Many studies have shown that infectious prions can enter the environment through saliva, feces, or urine from infected animals and decaying carcasses. However, we need to understand the specific contribution of this component to disease transmission events. Plants are logical environmental components to be evaluated since they grow in environments contaminated with CWD prions and are relevant for transmission. The main objective of this study is to characterize whether prions are transported to the roots and leaves of carrots, an edible plant commonly used in the human diet and as deer bait. We have grown carrot plants in CWD-infected soils. We harvested the carrots and separated them from the leaves. These materials were interrogated for their prion seeding activity using the PMCA. Infectivity was evaluated in mouse bioassays (intracerebral injections in Tg1536 mice). The PMCA analysis demonstrated CWD seeding activity in soils contaminated with CWD prions and in carrot plants (leaves and roots) grown on them. Bioassays showed that both plants and roots contained CWD prions sufficiently to induce disease. As expected, animals treated with prion-infected soils developed prion disease at shorter incubation periods (and complete attack rates) compared to plant components. We show that edible plant components can absorb prions from CWD-contaminated soils and transport them to their aerial parts. Our results indicate that edible plants could participate as vectors of CWD transmission.
***> We show that edible plant components can absorb prions from CWD-contaminated soils and transport them to their aerial parts.
***> Our results indicate that edible plants could participate as vectors of CWD transmission.
=====
15 Detection of CWD prions in plants collected from white-tailed deer farms
Francisca Bravo-Risi1,2, Paulina Soto1,2, Yumeng Huang1, Tracy A. Nichols3, Rodrigo Morales1,4
1Department of Neurology, The University of Texas Health Science Center at Houston, Houston, USA. 2Universidad Bernardo O’Higgins, Doctorado en Ciencias con Mención en Materiales Funcionales, Santiago, Chile. 3Veterinary Services Cervid Health Program, United States Department of Agriculture, Animal and Plant Health Inspection Service, Fort Collins, USA. 4Centro Integrativo de Biologia y Quimica Aplicada (CIBQA), Universidad Bernardo O’Higgins, Santiago, Chile
Abstract
Chronic wasting disease (CWD) is a prion disease affecting captive and free-ranging cervids. Transmission of CWD is thought to occur by direct animal-to-animal contact and by exposure to contaminated environmental fomites. CWD-prions are spread into the environment through biological fluids, excreta, and decaying carcasses. Extensive studies demonstrate that soils adsorb infectious prions which can remain attached for extended periods. Accordingly, prion seeding activity has been detected in natural and experimental samples including mineral licks, water sources, and dust. Although, detection of prion in plants under experimental conditions was demonstrated, the role of plants in CWD spreading has been poorly explored. In the present study, we optimized the detection of CWD-prions in plants using the protein misfolding cyclic amplification (PMCA) technology. Specifically, we compared NaPTA pretreatments and direct spiking of the sample into the PMCA reactions. After achieving technical optimizations, we screened multiple plant specimens collected from white-tailed deer breeding facilities displaying variable CWD prevalence. Our results demonstrated that CWD-prion detection for plants was optimal when samples were pre-treated with a NaPTA PrPSc enriching procedure. Our screening results showed positive PMCA activity for specimens collected from the farm with the highest CWD prevalence. Plants from the same site were tested for infectivity in meadow voles, a co-existing animal species that feeds from grass plants. Although meadow voles were highly susceptible to CWD prions by intra-cerebral administration, ingestion of contaminated grass did not induce prion replication in these rodents. These findings further contribute to understand the role of plants in CWD-prion transmission.
=====
8 The chronic wasting disease agent from white-tailed deer is infectious to humanized mice after passage through raccoons
Eric Cassmann1, Xu Qi2, Qingzhong Kong2, Justin Greenlee1
1USDA ARS, Ames, USA. 2Case Western Reserve University, Cleveland, USA
Abstract
The aim of this study was to evaluate the zoonotic potential of the raccoon passaged chronic wasting disease (CWD) agent in humanized transgenic mice in comparison with the North American CWD agent from the original white-tailed deer (WTD) host. Pooled brain (GG96) from CWD positive white-tailed deer was used to intracranially inoculate two WTD and one raccoon. Brain homogenates (10% w/v) from the raccoon and the WTD were used to intracranially inoculate transgenic mice (Tg40h) expressing the methionine 129 human prion protein. Brains and spleens were collected from mice at experimental endpoints of clinical disease or approximately 700 days post-inoculation. Tissues were divided and homogenized or fixed in 10% buffered neutral formalin. Immunohistochemistry, enzyme immunoassay, and western blot were used to detect misfolded prion protein (PrPSc) in tissue. Tg40h mice inoculated with the raccoon passaged CWD agent from WTD exhibited a 100% (12/12) attack rate with an average incubation period of 605 days. PrPSc was detected in brain tissue by enzyme immunoassay with an average optical density of 3.6/4.0 for positive brains. PrPSc also was detected in brain tissue by western blot and immunohistochemistry. No PrPSc was detected in the spleens of mice inoculated with the raccoon passaged CWD agent. Humanized mice inoculated with the CWD agent from WTD did not have detectable PrPSc using conventional immunoassay techniques. These results demonstrated that the host range of the CWD agent from WTD was expanded in our experimental model after one passage through raccoons.
***> These results demonstrated that the host range of the CWD agent from WTD was expanded in our experimental model after one passage through raccoons.
=====
Transmission of prion infectivity from CWD-infected macaque tissues to rodent models demonstrates the zoonotic potential of chronic wasting disease.
Samia Hannaoui1,2, Ginny Cheng1,2, Wiebke Wemheuer3, Walter Schulz-Schaeffer3, Sabine Gilch1,2, Hermann Schatzl1,2 1University of Calgary, Calgary, Canada. 2Calgary Prion Research Unit, Calgary, Canada. 3Institute of Neuropathology, Medical Faculty, Saarland University, Homburg/Saar, Germany
Abstract
We provide evidence by transmission experiments to different transgenic mouse models and bank voles that Cynomolgus macaques inoculated via different routes with CWD-positive cervid tissues harbor infectious prions. We used tissue materials from macaques inoculated with CWD to inoculate transgenic mice overexpressing cervid PrPC followed by transmission into bank voles. We used RTQuIC, immunoblot and PET blot analysis to assess brains, spinal cords, and tissues of the gastrointestinal tract (GIT) for the presence of prions. Our results show that macaque materials induced clinical disease in transgenic mice with low attack rates. Clinical mice did not display PrPSc in immunoblot, but showed low-levels of prion seeding activity. Further transmission into bank voles led to a 100% attack rate with typical PrPSc signature in immunoblot, and high-level prion seeding activity in brain, spinal cord and GIT tissues. Second passage studies led to 100% attack rate in voles inoculated with brain, spinal cord and small intestine material from first round animals, with shortened survival times indicating adaptation in the new host. This shows that prions detected in GIT tissues are infectious and transmissible. Further passage to cervidized mice revealed transmission with a 100% attack rate. Our findings demonstrate that macaques, considered the best model for the zoonotic potential of prions, were infected upon CWD challenge, including the oral one. The disease manifested as atypical in macaques and initial transgenic mouse transmissions, but with infectivity present at all times, as unveiled in the bank vole model with an unusual tissue tropism.
***> Further passage to cervidized mice revealed transmission with a 100% attack rate.
***> Our findings demonstrate that macaques, considered the best model for the zoonotic potential of prions, were infected upon CWD challenge, including the oral one.
****> The disease manifested as atypical in macaques and initial transgenic mouse transmissions, but with infectivity present at all times, as unveiled in the bank vole model with an unusual tissue tropism.
***> Epidemiologic surveillance of prion disease among cervid hunters and people likely to have consumed venison contaminated with chronic wasting disease
=====
Efficient CWD-like transmission of splenic prions in cervidized transgenic mice: a probable diagnostic marker for CWD infection in humans
Xu Qi, Liuting Qing, Manuel Camacho, Ignazio Cali, Qingzhong Kong
Department of Pathology, Case Western Reserve University, Cleveland, USA
Abstract
Multiple in vitro CWD-seeded human PrP conversion experiments and some animal model studies indicate that the species barrier for CWD to human transmission can be overcome, but whether CWD prion can infect humans in real life remains controversial. The very limited understanding on the likely features of CWD infection in humans and the lack of a reliable marker for identification of acquired human CWD cases contribute to this uncertainty. We aim to stablish a reliable diagnostic marker for CWD infections in humans should they occur.
We identified a couple of prion-positive spleens in humanized transgenic mice inoculated with some CWD isolates. Such experimentally generated splenic “humanized” CWD prions (termed eHuCWDsp) appear indistinguishable from prions in the brain of sCJDMM1 patients on Western blot. We compared eHuCWDsp with prions in the spleen from humanized mice infected with sCJDMM1 (termed sCJDsp) by bioassays in cervidized or humanized transgenic mice. Significantly, we found that eHuCWDsp can efficiently infect not only the humanized mice but also cervidized transgenic mice, and cervidized mice infected by eHuCWDsp produced prions and brain pathology that are practically identical to those of CWD-infected cervidized mice. In contrast, sCJDsp, similar to prions from sCJDMM1 patient brains, is poorly transmissible in the cervidized mice.
Our data demonstrate that high transmissibility with CWD features of splenic prions in cervidized transgenic mice is unique to acquired human CWD prions, and it may serve as a reliable marker to identify the first acquired human CWD cases.
***> Such experimentally generated splenic “humanized” CWD prions (termed eHuCWDsp) appear indistinguishable from prions in the brain of sCJDMM1 patients on Western blot.
=====
Are stable and highly zoonotic cervid prion strains possible?
Manuel Camacho, Xu Qi, Liuting Qing, Sydney Smith, Jieji Hu, Wanyun Tao, Ignazio Cali, Qingzhong Kong Department of Pathology, Case Western Reserve University, Cleveland, USA
Abstract
Whether CWD prions can infect humans remains unclear despite the very substantial scale and long history of human exposure of CWD in many states or provinces of USA and Caada. Multiple in vitro conversion experiments and in vivo animal studies indicate that the CWD-to-human transmission barrier is not unbreakable. A major long-term public health concern on CWD zoonosis is the emergence of highly zoonotic CWD strains. We aim to address the question of whether highly zoonotic CWD strains are possible. We inoculated a few sCJD brain samples into cervidized transgenic mice (Tg12), which were intended as negative controls for bioassays of brain tissues from sCJD cases who had hunted or consumed venison from CWD-endemic states. Some of the Tg12 mice became infected, resulting in a “cervidized” CJD strain that we termed CJDElkPrP. CJDElkPrP was further examined by serial passages in humanized or cervidized mice. We observed 100% transmission of the original CJDElkPrP in transgenic mice expressing human PrP. We passaged CJDElkPrP two more times in the Tg12 mice. We found that such second and third passage CJDElkPrP prions retained 100% transmission rate in the humanized mice. In contrast, we and others found zero or poor transmission of natural elk CWD isolates in humanized mice, despite that the natural elk CWD isolates and CJDElkPrP share the same elk PrP sequence. Our data indicate that highly zoonotic cervid prion strains are not only possible but also can be stably maintained in cervids.
***> Our data indicate that highly zoonotic cervid prion strains are not only possible but also can be stably maintained in cervids.
snip=====END
I HAVE NOT READ ALL THESE, BUT THOUGHT SOME OF YOU MIGHT FIND THIS INTERESTING!
kind regards, terry
intcwdsympo.files.wordpress.com/2023/06/final-agenda-with-abstracts.pdf?force_download=true