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Kevin R. Kazacos - One of the best experts on this subject based on the ideXlab platform.
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baylisascaris procyonis associated meningoencephalitis in a previously healthy adult california usa
Emerging Infectious Diseases, 2016Co-Authors: Charles Langelier, Michael J A Reid, Cathra Halabi, Natalie Witek, Alejandro Lariviere, Maulik P Shah, Peter Chinhong, Michael R Wilson, Vanja C Douglas, Kevin R. KazacosAbstract:After severe neurocognitive decline developed in an otherwise healthy 63-year-old man, brain magnetic resonance imaging showed eosinophilic meningoencephalitis and enhancing lesions. The patient tested positive for antibodies to Baylisascaris spp. roundworms, was treated with albendazole and dexamethasone, and showed improvement after 3 months. Baylisascariasis should be considered for all patients with eosinophilic meningitis.
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Update on Baylisascariasis, a Highly Pathogenic Zoonotic Infection
Clinical microbiology reviews, 2016Co-Authors: Carlos Graeff-teixeira, Alessandra Loureiro Morassutti, Kevin R. KazacosAbstract:Baylisascaris procyonis, the raccoon roundworm, infects a wide range of vertebrate animals, including humans, in which it causes a particularly severe type of larva migrans. It is an important cause of severe neurologic disease (neural larva migrans [NLM]) but also causes ocular disease (OLM; diffuse unilateral subacute neuroretinitis [DUSN]), visceral larva migrans (VLM), and covert/asymptomatic infections. B. procyonis is common and widespread in raccoons, and there is increasing recognition of human disease, making a clinical consideration of Baylisascariasis important. This review provides an update for this disease, especially its clinical relevance and diagnosis, and summarizes the clinical cases of human NLM and VLM known to date. Most diagnosed patients have been young children less than 2 years of age, although the number of older patients diagnosed in recent years has been increasing. The recent development of recombinant antigen-based serodiagnostic assays has aided greatly in the early diagnosis of this infection. Patients recovering with fewer severe sequelae have been reported in recent years, reinforcing the current recommendation that early treatment with albendazole and corticosteroids should be initiated at the earliest suspicion of Baylisascariasis. Considering the seriousness of this zoonotic infection, greater public and medical awareness is critical for the prevention and early treatment of human cases.
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Baylisascaris procyonis–Associated Meningoencephalitis in a Previously Healthy Adult, California, USA
Centers for Disease Control and Prevention, 2016Co-Authors: Charles Langelier, Michael J A Reid, Cathra Halabi, Natalie Witek, Alejandro Lariviere, Michael R Wilson, Maulik Shah, Peter Chin-hong, Vanja Douglas, Kevin R. KazacosAbstract:After severe neurocognitive decline developed in an otherwise healthy 63-year-old man, brain magnetic resonance imaging showed eosinophilic meningoencephalitis and enhancing lesions. The patient tested positive for antibodies to Baylisascaris spp. roundworms, was treated with albendazole and dexamethasone, and showed improvement after 3 months. Baylisascariasis should be considered for all patients with eosinophilic meningitis
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Interlaboratory Optimization and Evaluation of a Serological Assay for Diagnosis of Human Baylisascariasis
Clinical and vaccine immunology : CVI, 2013Co-Authors: Lisa N Rascoe, Patricia P Wilkins, Kevin R. Kazacos, Sukwan Handali, Cynthia Santamaria, Sriveny Dangoudoubiyam, Momar NdaoAbstract:A Western blot assay using a recombinant protein, recombinant Baylisascaris procyonis RAG1 protein (rBpRAG1), was developed for the diagnosis of human Baylisascariasis concurrently by the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, and the National Reference Centre for Parasitology (NRCP) in Montreal, Canada. Assay performance was assessed by testing 275 specimens at the CDC and 405 specimens at the NRCP. Twenty specimens from 16 cases of Baylisascariasis were evaluated. Eighteen were positive, with the assay correctly identifying 14 of 16 patients. The rBpRAG1 Western blot assay showed no cross-reactivity with Toxocara-positive serum and had an overall sensitivity of 88% and a specificity of 98%.
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Possible pet-associated Baylisascariasis in child, Canada.
Emerging infectious diseases, 2012Co-Authors: Shariq Haider, Kevin R. Kazacos, Krishna Khairnar, Donald S. Martin, James Yang, Filip Ralevski, Dylan R. PillaiAbstract:To the Editor: Baylisascaris procyonis, a roundworm parasite of raccoons (Procyon lotor), increasingly is being documented as a cause of severe human disease (1). Approximately 130 species of wild and domesticated animals have been affected with B. procyonis neural larva migrans, and the parasite is increasingly recognized as a cause of human encephalitis (2; K. Kazacos, unpub. data). The first recognized human case was reported in 1984 in a 10-month-old child in Pennsylvania, USA (3). Since then, ≈30 additional cases of severe or fatal B. procyonis encephalitis have been reported in the United States (4–7; K. Kazacos, pers. comm.). To our knowledge, only 1 account of human B. procyonis infection has been reported in Canada (in 2009) (8). We report another case of human B. procyonis infection in Canada, indicating its probable transmission from peridomestic raccoons.
Mark L. Eberhard - One of the best experts on this subject based on the ideXlab platform.
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baylisascaris procyonis roundworm seroprevalence among wildlife rehabilitators united states and canada 2012 2015
Emerging Infectious Diseases, 2016Co-Authors: Sarah Grace Sapp, Lisa N Rascoe, Elizabeth B Gray, Dana Woodhall, Susan P Montgomery, Karen L Bailey, Patricia P Wilkins, Mark L. Eberhard, Sukwan Handali, Emily W LankauAbstract:: Baylisascaris procyonis roundworms can cause potentially fatal neural larva migrans in many species, including humans. However, the clinical spectrum of Baylisascariasis is not completely understood. We tested 347 asymptomatic adult wildlife rehabilitators for B. procyonis antibodies; 24 were positive, suggesting that subclinical Baylisascariasis is occurring among this population.
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Baylisascaris procyonis Roundworm Seroprevalence among Wildlife Rehabilitators, United States and Canada, 2012–2015
Centers for Disease Control and Prevention, 2016Co-Authors: Sarah Grace Sapp, Lisa N Rascoe, Elizabeth B Gray, Dana Woodhall, Susan P Montgomery, Karen L Bailey, Patricia P Wilkins, Mark L. Eberhard, Sukwan Handali, Emily W LankauAbstract:Baylisascaris procyonis roundworms can cause potentially fatal neural larva migrans in many species, including humans. However, the clinical spectrum of Baylisascariasis is not completely understood. We tested 347 asymptomatic adult wildlife rehabilitators for B. procyonis antibodies; 24 were positive, suggesting that subclinical Baylisascariasis is occurring among this population
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procyonis Eggs
2013Co-Authors: Shira C Shafir, Frank Sorvillo, Teresa Sorvillo, Mark L. EberhardAbstract:is rare but often fatal and typically affects children. We attempted to determine parameters of viability and methods of inactivating the eggs of these roundworms. Loss of viability resulted when eggs were heated to 62°C or desiccated for 7 months but not when frozen at –15°C for 6 months. Baylisascaris procyonis, the common intestinal roundworm of raccoons, has increasingly been recognized as a source of severe, often fatal, neurologic disease in humans, particularly children (1,2). Although this devastating disease is rare, lack of effective treatment and the widespread distribution of raccoons in close association with humans make Baylisascariasis a disease that seriously affects public health (3). Raccoons infected with B. procyonis roundworms can shed millions of eggs in their feces daily (4). Given the habit of raccoons to defecat
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thermal death point of baylisascaris procyonis eggs
Emerging Infectious Diseases, 2007Co-Authors: Shira C Shafir, Laurel Moore, Frank Sorvillo, Teresa Sorvillo, Matthew E. Wise, Wei Wang, Mark L. EberhardAbstract:To the Editor: In the past 20 years, Baylisascaris procyonis, the common intestinal roundworm of raccoons, has increasingly been recognized as a source of severe human neurologic disease that particularly affects children (1,2). Although human Baylisascariasis appears to be rare, the devastating neurologic disease caused by this infection and the lack of effective treatment make it a disease of public health importance (3). Adult raccoons infected with B. procyonis can shed millions of unembryonated eggs in feces daily (4). Once infective, eggs can remain viable in the environment for years and are resistant to most decontamination methods (5). Given the severe and untreatable nature of Baylisascariasis, and the hardy nature of B. procyonis eggs, information on optimal methods to inactivate B. procyonis eggs is essential. To guide attempts at environmental decontamination as well as personal protection in the case of accidental or intentional contamination of drinking water supplies, we attempted to determine the thermal death point of B. procyonis eggs. Experiments were conducted in which 150 μL each of embryonated eggs, at a concentration of 100 eggs per μL, were added to six 1-mL polypropylene tubes of sterile water. The 6 tubes were then added to a water bath at 35°C and allowed to sit for 10 min to equilibrate. Then the temperature of the water bath was slowly increased at a rate of ≈5°C per 7 min, and 1 tube was removed at each 5° increment from 37°C to 62°C. Eggs were then examined by light microscopy to determine whether the larvae were still viable, as judged by larval motility (Figure). The experiment was repeated by using a more objective assessment of viability through examination of hatched larvae. Inactivation was measured with a viability dye (methylene blue) exclusion method in which uptake of dye by larvae indicates cell death and inactivation. After the eggs were removed from the heat, the mammilated layer was removed through exposure to undiluted chlorine beach and then washed 5 times in 0.85% saline for 1 min at 600×g. Hatching was achieved by the glass bead method (6,7). Hatched larvae were then removed and mixed 1:1 with a 1:10,000 dilution of methylene blue. Viable larvae remained motile and had an intact cuticle that could not be penetrated by the stain, whereas nonviable larvae took up the methylene blue along the cuticle and stained blue (8). Figure Hatched, stained, nonviable Baylisascaris procyonis larvae (magnification ×10). The experiment was repeated by adding the heated water, in 5° increments between 37°C and 62°C, directly into the tube containing the eggs. The duration of exposure of the eggs to the water was <1 min. The eggs were then processed in the same manner as previously described and examined by light microscopy. All experiments were replicated. All larvae remained viable in water up to 47°C; >75% of the larvae were viable at 52°C and 57°C; complete inactivation occurred at 62°C. When the heated water was added directly to the infectious eggs, all larvae remained viable up to 42°C, and most larvae were observed to be viable at 47°C and 52°C; complete inactivation occurred at 57°C. These preliminary findings indicate that B. procyonis eggs have a thermal death point, <62°C, very similar to the thermal death point of Ascaris lumbricoides and A. suum (9). Given the widespread prevalence of B. procyonis in raccoons, the close association of raccoons with human populations, and the serious nature of infection, identification of the thermal death point of infectious B. procyonis larvae has important implications. Potential for human infection can be mitigated by decontaminating areas where B. procyonis eggs are known to be found. Health authorities and parasitologists are routinely contacted by citizens and organizations regarding concerns about areas that have been contaminated with raccoon feces, including yards, pools, and homes. Unfortunately, no comprehensive studies have been published that describe practical and effective methods for decontamination of areas where B. procyonis eggs are present. The recognition of complete inactivation of eggs at relatively low temperatures will provides guidance in circumstances in which natural or intentional contamination with B. procyonis eggs requires disinfection efforts and indicates that approaches well short of incineration or boiling will be effective. Furthermore, these results suggest that temperatures achievable in point-of-use hot water heaters (household units) can deactivate infectious B. procyonis eggs, thus providing an option for maintaining safe drinking water during a possible event of bioterrorism or a “boil water advisory.” However, further efforts are needed to determine the effectiveness of heat and other disinfection methods on inactivation of eggs in natural circumstances such as in feces or contaminated play areas including soil.
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Thermal death point of Baylisascaris procyonis eggs.
Emerging infectious diseases, 2007Co-Authors: Shira C Shafir, Laurel Moore, Frank Sorvillo, Teresa Sorvillo, Matthew E. Wise, Wei Wang, Mark L. EberhardAbstract:To the Editor: In the past 20 years, Baylisascaris procyonis, the common intestinal roundworm of raccoons, has increasingly been recognized as a source of severe human neurologic disease that particularly affects children (1,2). Although human Baylisascariasis appears to be rare, the devastating neurologic disease caused by this infection and the lack of effective treatment make it a disease of public health importance (3). Adult raccoons infected with B. procyonis can shed millions of unembryonated eggs in feces daily (4). Once infective, eggs can remain viable in the environment for years and are resistant to most decontamination methods (5). Given the severe and untreatable nature of Baylisascariasis, and the hardy nature of B. procyonis eggs, information on optimal methods to inactivate B. procyonis eggs is essential. To guide attempts at environmental decontamination as well as personal protection in the case of accidental or intentional contamination of drinking water supplies, we attempted to determine the thermal death point of B. procyonis eggs. Experiments were conducted in which 150 μL each of embryonated eggs, at a concentration of 100 eggs per μL, were added to six 1-mL polypropylene tubes of sterile water. The 6 tubes were then added to a water bath at 35°C and allowed to sit for 10 min to equilibrate. Then the temperature of the water bath was slowly increased at a rate of ≈5°C per 7 min, and 1 tube was removed at each 5° increment from 37°C to 62°C. Eggs were then examined by light microscopy to determine whether the larvae were still viable, as judged by larval motility (Figure). The experiment was repeated by using a more objective assessment of viability through examination of hatched larvae. Inactivation was measured with a viability dye (methylene blue) exclusion method in which uptake of dye by larvae indicates cell death and inactivation. After the eggs were removed from the heat, the mammilated layer was removed through exposure to undiluted chlorine beach and then washed 5 times in 0.85% saline for 1 min at 600×g. Hatching was achieved by the glass bead method (6,7). Hatched larvae were then removed and mixed 1:1 with a 1:10,000 dilution of methylene blue. Viable larvae remained motile and had an intact cuticle that could not be penetrated by the stain, whereas nonviable larvae took up the methylene blue along the cuticle and stained blue (8). Figure Hatched, stained, nonviable Baylisascaris procyonis larvae (magnification ×10). The experiment was repeated by adding the heated water, in 5° increments between 37°C and 62°C, directly into the tube containing the eggs. The duration of exposure of the eggs to the water was 75% of the larvae were viable at 52°C and 57°C; complete inactivation occurred at 62°C. When the heated water was added directly to the infectious eggs, all larvae remained viable up to 42°C, and most larvae were observed to be viable at 47°C and 52°C; complete inactivation occurred at 57°C. These preliminary findings indicate that B. procyonis eggs have a thermal death point,
Guangyou Yang - One of the best experts on this subject based on the ideXlab platform.
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Prokaryotic Expression and Serodiagnostic Potential of Glyceraldehyde-3-Phosphate Dehydrogenase and Thioredoxin Peroxidase from Baylisascaris schroederi.
Genes, 2017Co-Authors: Ying Sun, Xuerong Peng, Yue Xie, Weiming Lai, Bo Jing, Guangyou YangAbstract:Baylisascaris schroederi, a roundworm parasite of giant pandas, badly affects the health of its hosts. Diagnosis of this disease currently depends mainly on sedimentation floatation and Polymerase Chain Reaction (PCR) methods to detect the eggs. However, neither of these methods is suitable for diagnosis of early-stage panda Baylisascariasis and no information on early diagnosis of this disease is available so far. Therefore, to develop an effective serologic diagnostic method, this study produced recombinant glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and thioredoxin peroxidase (Tpx) proteins from B. schroederi using a prokaryotic expression system. We determined the immunological characteristics of these proteins and their location in the parasite. Indirect enzyme-linked immunosorbent assays (ELISAs) were established to detect B. schroederi infection in giant pandas based on GAPDH and Tpx respectively. The open reading frame of the GAPDH gene (1083 bp) encoded a 39 kDa protein, while the predicted molecular weight of Tpx (588 bp) was 21.6 kDa. Western-blotting analysis revealed that both recombinant proteins could be recognized with positive serum of pandas infected with B. schroederi. Immunohistochemical staining showed that the endogenous GAPDH of B. schroederi was widely distributed in the worm while Tpx was mainly localized in the muscle, eggs, gut wall, uterus wall and hypodermis. Serological tests showed that the GAPDH-based indirect ELISA had a sensitivity of 95.83% and specificity of 100%, while the test using Tpx as the antigen had sensitivity of 75% and specificity of 91.7%. Thus, B. schroederi Tpx is unsuitable as a diagnostic antigen for Baylisascariasis, but B. schroederi GAPDH is a good candidate diagnostic antigen for B. schroederi in pandas.
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RESEARCH Open Access Absence of genetic structure in Baylisascaris
2016Co-Authors: Xuerong Peng, Guangyou YangAbstract:schroederi populations, a giant panda parasite, determined by mitochondrial sequencing assist in the control of Baylisascariasis in giant pandas
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cloning and characterization of a novel sigma like glutathione s transferase from the giant panda parasitic nematode baylisascaris schroederi
Parasites & Vectors, 2015Co-Authors: Xuan Zhou, Xuerong Peng, Chengdong Wang, Xiaobin Gu, Zhihe Zhang, Lin Chen, Tao Wang, Guangyou YangAbstract:Background Baylisascaris schroederi, an intestinal nematode of the giant panda, is the cause of the often fatal disease, Baylisascariasis. Glutathione S-transferases (GSTs) are versatile enzymes that can affect parasite survival and parasite-host interactions and, are therefore, potential targets for the development of diagnostic tests and vaccines.
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absence of genetic structure in baylisascaris schroederi populations a giant panda parasite determined by mitochondrial sequencing
Parasites & Vectors, 2014Co-Authors: Xuan Zhou, Xuerong Peng, Chengdong Wang, Xiaobin Gu, Zhihe Zhang, Tao Wang, Guangyou YangAbstract:Background: Infection with the parasitic nematode, Baylisascaris schroederi (Ascaridida: Nematoda), is one of the most important causes of death in giant pandas, and was responsible for half of deaths between 2001 and 2005. Mitochondrial (mt) DNA sequences of parasites can unveil their genetic diversity and depict their likely dynamic evolution and therefore may provide insights into parasite survival and responses to host changes, as well as parasite control. Methods: Based on previous studies, the present study further annotated the genetic variability and structure of B. schroederi populations by combining two different mtDNA markers, ATPase subunit 6 (atp6) and cytochrome c oxidase subunit I (cox1). Both sequences were completely amplified and genetically analyzed among 57 B. schroederi isolates, which were individually collected from ten geographical regions located in three important giant panda habitats in China (Minshan, Qionglai and Qinling mountain ranges). Results: For the DNA dataset, we identified 20 haplotypes of atp6, 24 haplotypes of cox1, and 39 haplotypes of atp6 +cox1. Further haplotype network and phylogenetic analyses demonstrated that B. schroederi populations were predominantly driven by three common haplotypes, atp6 A1, cox1 C10, and atp6 +cox1 H11. However, due to low rates of gene differentiation between the three populations, both the atp6 and cox1 genes appeared not to be significantly associated with geographical divisions. In addition, high gene flow was detected among the B. schroederi populations, consistent with previous studies, suggesting that this parasite may be essentially homogenous across endemic areas. Finally, neutrality tests and mismatch analysis indicated that B. schroederi had undergone earlier demographic expansion. Conclusions: These results confirmed that B. schroederi populations do not follow a pattern of isolation by distance, further revealing the possible existence of physical connections before geographic separation. This study should also contribute to an improved understanding of the population genetics and evolutionary biology of B. schroederi and assist in the control of Baylisascariasis in giant pandas.
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complete mitochondrial genomes of baylisascaris schroederi baylisascaris ailuri and baylisascaris transfuga from giant panda red panda and polar bear
Gene, 2011Co-Authors: Zhihe Zhang, Shuxian Wang, Xuerong Peng, Chengdong Wang, Xiaobin Gu, Yan Fu, Yan Li, Zhigang Chen, Guangyou YangAbstract:Abstract Roundworms of the genus Baylisascaris are the most common parasitic nematodes of the intestinal tracts of wild mammals, and most of them have significant impacts in veterinary and public health. Mitochondrial (mt) genomes provide a foundation for studying epidemiology and ecology of these parasites and therefore may be used to assist in the control of Baylisascariasis. Here, we determined the complete sequences of mtDNAs for Baylisascaris schroederi , Baylisascaris ailuri and Baylisascaris transfuga , with 14,778 bp, 14,657 bp and 14,898 bp in size, respectively. Each mtDNA encodes 12 protein-coding genes, 22 transfer RNAs and 2 ribosomal RNAs, typical for other chromadorean nematodes. The gene arrangements for the three Baylisascaris species are the same as those of the Ascaridata species, but radically different from those of the Spirurida species. Phylogenetic analysis based on concatenated amino acid sequences of 12 protein-coding genes from nine nematode species indicated that the three Baylisascaris species are more closely related to Ascaris suum than to the three Toxocara species ( Toxocara canis, Toxocara cati and Toxocara malaysiensis ) and Anisakis simplex , and that B. ailuri is more closely related to B. transfuga than to B. schroeder . The determination of the complete mt genome sequences for these three Baylisascaris species (the first members of the genus Baylisascaris ever sequenced) is of importance in refining the phylogenetic relationships within the order Ascaridida, and provides new molecular data for population genetic, systematic, epidemiological and ecological studies of parasitic nematodes of socio-economic importance in wildlife.
Xuerong Peng - One of the best experts on this subject based on the ideXlab platform.
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Prokaryotic Expression and Serodiagnostic Potential of Glyceraldehyde-3-Phosphate Dehydrogenase and Thioredoxin Peroxidase from Baylisascaris schroederi.
Genes, 2017Co-Authors: Ying Sun, Xuerong Peng, Yue Xie, Weiming Lai, Bo Jing, Guangyou YangAbstract:Baylisascaris schroederi, a roundworm parasite of giant pandas, badly affects the health of its hosts. Diagnosis of this disease currently depends mainly on sedimentation floatation and Polymerase Chain Reaction (PCR) methods to detect the eggs. However, neither of these methods is suitable for diagnosis of early-stage panda Baylisascariasis and no information on early diagnosis of this disease is available so far. Therefore, to develop an effective serologic diagnostic method, this study produced recombinant glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and thioredoxin peroxidase (Tpx) proteins from B. schroederi using a prokaryotic expression system. We determined the immunological characteristics of these proteins and their location in the parasite. Indirect enzyme-linked immunosorbent assays (ELISAs) were established to detect B. schroederi infection in giant pandas based on GAPDH and Tpx respectively. The open reading frame of the GAPDH gene (1083 bp) encoded a 39 kDa protein, while the predicted molecular weight of Tpx (588 bp) was 21.6 kDa. Western-blotting analysis revealed that both recombinant proteins could be recognized with positive serum of pandas infected with B. schroederi. Immunohistochemical staining showed that the endogenous GAPDH of B. schroederi was widely distributed in the worm while Tpx was mainly localized in the muscle, eggs, gut wall, uterus wall and hypodermis. Serological tests showed that the GAPDH-based indirect ELISA had a sensitivity of 95.83% and specificity of 100%, while the test using Tpx as the antigen had sensitivity of 75% and specificity of 91.7%. Thus, B. schroederi Tpx is unsuitable as a diagnostic antigen for Baylisascariasis, but B. schroederi GAPDH is a good candidate diagnostic antigen for B. schroederi in pandas.
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RESEARCH Open Access Absence of genetic structure in Baylisascaris
2016Co-Authors: Xuerong Peng, Guangyou YangAbstract:schroederi populations, a giant panda parasite, determined by mitochondrial sequencing assist in the control of Baylisascariasis in giant pandas
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cloning and characterization of a novel sigma like glutathione s transferase from the giant panda parasitic nematode baylisascaris schroederi
Parasites & Vectors, 2015Co-Authors: Xuan Zhou, Xuerong Peng, Chengdong Wang, Xiaobin Gu, Zhihe Zhang, Lin Chen, Tao Wang, Guangyou YangAbstract:Background Baylisascaris schroederi, an intestinal nematode of the giant panda, is the cause of the often fatal disease, Baylisascariasis. Glutathione S-transferases (GSTs) are versatile enzymes that can affect parasite survival and parasite-host interactions and, are therefore, potential targets for the development of diagnostic tests and vaccines.
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absence of genetic structure in baylisascaris schroederi populations a giant panda parasite determined by mitochondrial sequencing
Parasites & Vectors, 2014Co-Authors: Xuan Zhou, Xuerong Peng, Chengdong Wang, Xiaobin Gu, Zhihe Zhang, Tao Wang, Guangyou YangAbstract:Background: Infection with the parasitic nematode, Baylisascaris schroederi (Ascaridida: Nematoda), is one of the most important causes of death in giant pandas, and was responsible for half of deaths between 2001 and 2005. Mitochondrial (mt) DNA sequences of parasites can unveil their genetic diversity and depict their likely dynamic evolution and therefore may provide insights into parasite survival and responses to host changes, as well as parasite control. Methods: Based on previous studies, the present study further annotated the genetic variability and structure of B. schroederi populations by combining two different mtDNA markers, ATPase subunit 6 (atp6) and cytochrome c oxidase subunit I (cox1). Both sequences were completely amplified and genetically analyzed among 57 B. schroederi isolates, which were individually collected from ten geographical regions located in three important giant panda habitats in China (Minshan, Qionglai and Qinling mountain ranges). Results: For the DNA dataset, we identified 20 haplotypes of atp6, 24 haplotypes of cox1, and 39 haplotypes of atp6 +cox1. Further haplotype network and phylogenetic analyses demonstrated that B. schroederi populations were predominantly driven by three common haplotypes, atp6 A1, cox1 C10, and atp6 +cox1 H11. However, due to low rates of gene differentiation between the three populations, both the atp6 and cox1 genes appeared not to be significantly associated with geographical divisions. In addition, high gene flow was detected among the B. schroederi populations, consistent with previous studies, suggesting that this parasite may be essentially homogenous across endemic areas. Finally, neutrality tests and mismatch analysis indicated that B. schroederi had undergone earlier demographic expansion. Conclusions: These results confirmed that B. schroederi populations do not follow a pattern of isolation by distance, further revealing the possible existence of physical connections before geographic separation. This study should also contribute to an improved understanding of the population genetics and evolutionary biology of B. schroederi and assist in the control of Baylisascariasis in giant pandas.
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potential of recombinant inorganic pyrophosphatase antigen as a new vaccine candidate against baylisascaris schroederi in mice
Veterinary Research, 2013Co-Authors: Sijie Chen, Shuxian Wang, Chengdong Wang, Xiaobin Gu, Zhihe Zhang, Xuan Zhou, Desheng Li, Hua Yu, Xiang Nong, Xuerong PengAbstract:The intestinal nematode Baylisascaris schroederi is an important cause of death for wild and captive giant pandas. Inorganic pyrophosphatases (PPases) are critical for development and molting in nematode parasites and represent potential targets for vaccination. Here, a new PPase homologue, Bsc-PYP-1, from B. schroederi was identified and characterized, and its potential as a vaccine candidate was evaluated in a mouse challenge model. Sequence alignment of PPases from nematode parasites and other organisms show that Bsc-PYP-1 is a nematode-specific member of the family I soluble PPases. Immunohistochemistry revealed strong localization of native Bsc-PYP-1 to the body wall, gut epithelium, ovary and uterus of adult female worms. Additionally, Bsc-PYP-1 homologues were found in roundworms infecting humans (Ascaris lumbricoides), swine (Ascaris suum) and dogs (Toxocara canis). In two vaccine trials, recombinant Bsc-PYP-1 (rBsc-PYP-1) formulated with Freund complete adjuvant induced significantly high antigen-specific immunoglobulin (Ig)G but no IgE or IgM responses. Analysis of IgG-subclass profiles revealed a greater increase of IgG1 than IgG2a. Splenocytes from rBsc-PYP-1/FCA-immunized mice secreted low levels of T helper (Th)1-type cytokines, interferon-γ and interleukin (IL)-2, while producing significantly high levels of IL-10 and significantly elevated levels of IL-4 (Th2 cytokines) after stimulation with rBsc-PYP-1 in vitro. Finally, vaccinated mice had 69.02–71.15% reductions (in 2 experiments) in larval recovery 7 days post-challenge (dpc) and 80% survival at 80 dpc. These results suggest that Th2-mediated immunity elicited by rBsc-PYP-1 provides protection against B. schroederi, and the findings should contribute to further development of Bsc-PYP-1 as a candidate vaccine against Baylisascariasis.
Laurel Moore - One of the best experts on this subject based on the ideXlab platform.
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Thermal death point of Baylisascaris procyonis eggs.
Emerging infectious diseases, 2007Co-Authors: Shira C Shafir, Laurel Moore, Frank Sorvillo, Teresa Sorvillo, Matthew E. Wise, Wei Wang, Mark L. EberhardAbstract:To the Editor: In the past 20 years, Baylisascaris procyonis, the common intestinal roundworm of raccoons, has increasingly been recognized as a source of severe human neurologic disease that particularly affects children (1,2). Although human Baylisascariasis appears to be rare, the devastating neurologic disease caused by this infection and the lack of effective treatment make it a disease of public health importance (3). Adult raccoons infected with B. procyonis can shed millions of unembryonated eggs in feces daily (4). Once infective, eggs can remain viable in the environment for years and are resistant to most decontamination methods (5). Given the severe and untreatable nature of Baylisascariasis, and the hardy nature of B. procyonis eggs, information on optimal methods to inactivate B. procyonis eggs is essential. To guide attempts at environmental decontamination as well as personal protection in the case of accidental or intentional contamination of drinking water supplies, we attempted to determine the thermal death point of B. procyonis eggs. Experiments were conducted in which 150 μL each of embryonated eggs, at a concentration of 100 eggs per μL, were added to six 1-mL polypropylene tubes of sterile water. The 6 tubes were then added to a water bath at 35°C and allowed to sit for 10 min to equilibrate. Then the temperature of the water bath was slowly increased at a rate of ≈5°C per 7 min, and 1 tube was removed at each 5° increment from 37°C to 62°C. Eggs were then examined by light microscopy to determine whether the larvae were still viable, as judged by larval motility (Figure). The experiment was repeated by using a more objective assessment of viability through examination of hatched larvae. Inactivation was measured with a viability dye (methylene blue) exclusion method in which uptake of dye by larvae indicates cell death and inactivation. After the eggs were removed from the heat, the mammilated layer was removed through exposure to undiluted chlorine beach and then washed 5 times in 0.85% saline for 1 min at 600×g. Hatching was achieved by the glass bead method (6,7). Hatched larvae were then removed and mixed 1:1 with a 1:10,000 dilution of methylene blue. Viable larvae remained motile and had an intact cuticle that could not be penetrated by the stain, whereas nonviable larvae took up the methylene blue along the cuticle and stained blue (8). Figure Hatched, stained, nonviable Baylisascaris procyonis larvae (magnification ×10). The experiment was repeated by adding the heated water, in 5° increments between 37°C and 62°C, directly into the tube containing the eggs. The duration of exposure of the eggs to the water was 75% of the larvae were viable at 52°C and 57°C; complete inactivation occurred at 62°C. When the heated water was added directly to the infectious eggs, all larvae remained viable up to 42°C, and most larvae were observed to be viable at 47°C and 52°C; complete inactivation occurred at 57°C. These preliminary findings indicate that B. procyonis eggs have a thermal death point,
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thermal death point of baylisascaris procyonis eggs
Emerging Infectious Diseases, 2007Co-Authors: Shira C Shafir, Laurel Moore, Frank Sorvillo, Teresa Sorvillo, Matthew E. Wise, Wei Wang, Mark L. EberhardAbstract:To the Editor: In the past 20 years, Baylisascaris procyonis, the common intestinal roundworm of raccoons, has increasingly been recognized as a source of severe human neurologic disease that particularly affects children (1,2). Although human Baylisascariasis appears to be rare, the devastating neurologic disease caused by this infection and the lack of effective treatment make it a disease of public health importance (3). Adult raccoons infected with B. procyonis can shed millions of unembryonated eggs in feces daily (4). Once infective, eggs can remain viable in the environment for years and are resistant to most decontamination methods (5). Given the severe and untreatable nature of Baylisascariasis, and the hardy nature of B. procyonis eggs, information on optimal methods to inactivate B. procyonis eggs is essential. To guide attempts at environmental decontamination as well as personal protection in the case of accidental or intentional contamination of drinking water supplies, we attempted to determine the thermal death point of B. procyonis eggs. Experiments were conducted in which 150 μL each of embryonated eggs, at a concentration of 100 eggs per μL, were added to six 1-mL polypropylene tubes of sterile water. The 6 tubes were then added to a water bath at 35°C and allowed to sit for 10 min to equilibrate. Then the temperature of the water bath was slowly increased at a rate of ≈5°C per 7 min, and 1 tube was removed at each 5° increment from 37°C to 62°C. Eggs were then examined by light microscopy to determine whether the larvae were still viable, as judged by larval motility (Figure). The experiment was repeated by using a more objective assessment of viability through examination of hatched larvae. Inactivation was measured with a viability dye (methylene blue) exclusion method in which uptake of dye by larvae indicates cell death and inactivation. After the eggs were removed from the heat, the mammilated layer was removed through exposure to undiluted chlorine beach and then washed 5 times in 0.85% saline for 1 min at 600×g. Hatching was achieved by the glass bead method (6,7). Hatched larvae were then removed and mixed 1:1 with a 1:10,000 dilution of methylene blue. Viable larvae remained motile and had an intact cuticle that could not be penetrated by the stain, whereas nonviable larvae took up the methylene blue along the cuticle and stained blue (8). Figure Hatched, stained, nonviable Baylisascaris procyonis larvae (magnification ×10). The experiment was repeated by adding the heated water, in 5° increments between 37°C and 62°C, directly into the tube containing the eggs. The duration of exposure of the eggs to the water was <1 min. The eggs were then processed in the same manner as previously described and examined by light microscopy. All experiments were replicated. All larvae remained viable in water up to 47°C; >75% of the larvae were viable at 52°C and 57°C; complete inactivation occurred at 62°C. When the heated water was added directly to the infectious eggs, all larvae remained viable up to 42°C, and most larvae were observed to be viable at 47°C and 52°C; complete inactivation occurred at 57°C. These preliminary findings indicate that B. procyonis eggs have a thermal death point, <62°C, very similar to the thermal death point of Ascaris lumbricoides and A. suum (9). Given the widespread prevalence of B. procyonis in raccoons, the close association of raccoons with human populations, and the serious nature of infection, identification of the thermal death point of infectious B. procyonis larvae has important implications. Potential for human infection can be mitigated by decontaminating areas where B. procyonis eggs are known to be found. Health authorities and parasitologists are routinely contacted by citizens and organizations regarding concerns about areas that have been contaminated with raccoon feces, including yards, pools, and homes. Unfortunately, no comprehensive studies have been published that describe practical and effective methods for decontamination of areas where B. procyonis eggs are present. The recognition of complete inactivation of eggs at relatively low temperatures will provides guidance in circumstances in which natural or intentional contamination with B. procyonis eggs requires disinfection efforts and indicates that approaches well short of incineration or boiling will be effective. Furthermore, these results suggest that temperatures achievable in point-of-use hot water heaters (household units) can deactivate infectious B. procyonis eggs, thus providing an option for maintaining safe drinking water during a possible event of bioterrorism or a “boil water advisory.” However, further efforts are needed to determine the effectiveness of heat and other disinfection methods on inactivation of eggs in natural circumstances such as in feces or contaminated play areas including soil.
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baylisascaris procyonis in california
Emerging Infectious Diseases, 2004Co-Authors: Laurel Moore, Frank Sorvillo, O G W BerlinAbstract:To the Editor: We read with interest the article of Roussere et al. on the distribution of Baylisascaris procyonis eggs in northern California communities (1). The widespread dissemination and high density of raccoon latrines in residential areas clearly pose potential health risks, particularly to young children. While California has reported more cases of Baylisascariasis than any other state, few published studies have reported on the distribution and prevalence of this helminth in the region. In 2001, we conducted a study to determine the presence of B. procyonis in the Santa Barbara area by examining roadkill raccoons recovered by animal control staff and stored in a refrigerated facility. On examination, the digestive tract from the stomach to the rectum was removed and tested for B. procyonis worms and eggs. Of 26 raccoons examined, 24 (92%, 95% confidence interval 75%–99%) were positive for B. procyonis infection. B. procyonis worms were found in 85% of the animals examined and eggs were found in 73%. Pet food was frequently found (43%) in the stomach contents of examined raccoons, indicating that such food was made accessible to these animals, either intentionally or inadvertently by residents. B. procyonis has been identified along the central coast of California, which expands the known range of this helminthic zoonotic agent. This finding, coupled with other published studies, indicates that Baylisascaris may be prevalent throughout the state (1,2). Although our study was based on a small sample of selected raccoons, the high infection rate is cause for concern and indicates the potential for human exposure. A presumptive case of B. procyonis infection in an 11-month-old child was reported in Santa Barbara in 2003 (1). Determining the distribution and prevalence of B. procyonis is necessary to inform local healthcare providers, public health authorities, and the public of the potential risk. Using road-kill raccoons is a relatively easy method for quickly assessing the presence of B. procyonis in a community. Also, this approach avoids trapping and handling live animals and allows stomach contents to be examined to determine where raccoons are feeding. Data from such assessments must be interpreted with caution, since they may not represent all raccoons in an area.