Colorado Tick Fever: Prolonged Viremia in Hibernating Citellus Lateralis *

Emmons, Richard W.

doi:10.4269/ajtmh.1966.15.428

Cited by 19 publications

(11 citation statements)

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“…Whether this is because cells are less active in the cold, or to avoid activating damaging macrophage or neutrophil-mediated inflammatory responses cannot be discerned from these results (73). Acquired immunity to infections is suppressed during hibernation (16,27,32). The switch to an innate immune response may also reflect the pathogens that a ground squirrel is most likely to encounter.…”

Section: Discussionmentioning

confidence: 99%

Effects of hibernation on bone marrow transcriptome in thirteen-lined ground squirrels

Cooper

Sell

Fahrenkrog

et al. 2016

Physiological Genomics

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M. Effects of hibernation on bone marrow transcriptome in thirteen-lined ground squirrels. Physiol Genomics 48: 513-525, 2016. First published May 20, 2016 doi:10.1152/physiolgenomics.00120.2015.-Mammalian hibernators adapt to prolonged periods of immobility, hypometabolism, hypothermia, and oxidative stress, each capable of reducing bone marrow activity. In this study bone marrow transcriptomes were compared among thirteen-lined ground squirrels collected in July, winter torpor, and winter interbout arousal (IBA). The results were consistent with a suppression of acquired immune responses, and a shift to innate immune responses during hibernation through higher complement expression. Consistent with the increase in adipocytes found in bone marrow of hibernators, expression of genes associated with white adipose tissue are higher during hibernation. Genes that should strengthen the bone by increasing extracellular matrix were higher during hibernation, especially the collagen genes. Finally, expression of heat shock proteins were lower, and cold-response genes were higher, during hibernation. No differential expression of hematopoietic genes involved in erythrocyte or megakaryocyte production was observed. This global view of the changes in the bone marrow transcriptome over both short term (torpor vs. IBA) and long term (torpor vs. July) hypothermia can explain several observations made about circulating blood cells and the structure and strength of the bone during hibernation. erythrocyte; leukocyte; megakaryocyte; osteoblast; adipose BONE MARROW IS A COMPLEX ORGAN consisting of many different cell types and stem cell pools. These cells express both unique and common sets of genes and likely influence each other's activities. Hematopoietic stem cells can differentiate into lymphoid progenitor cells that produce natural killer cells and lymphocytes, or into myeloid progenitor cells that give rise to erythrocytes, the remaining leukocytes, and megakaryocytes. Megakaryocytes in turn shed anucleated platelets involved in blood clotting and inflammation. Bone marrow resident mesenchymal stem cells can differentiate to produce resident bone cells including osteoblasts, adipocytes, and chondrocytes (64). Osteoblasts can terminally differentiate into osteocytes and are involved in maintaining bone strength and extracellular matrix production. Bone marrow adipose composition is affected by age, diet, and disease states. Bone marrow may also contain skeletal muscle and hepatocyte stem cell pools. Because of the rapid rate of mitosis by multiple resident stem cell pools, bone marrow is sensitive to damage by radiation and chemotherapy, leaving patients immunocompromised and anemic (25). Bone mineral density and collagen are decreased by prolonged disuse such as bed rest or immobilization (45,86). Recent studies have also demonstrated an increase in neutrophils, natural killer cells, and lymphocytes and a decrease in monocytes in patients subjected to 60 days of bed rest (38). Finally, bone marrow adipocytes increase in ...

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Section: Discussionmentioning

confidence: 99%

Effects of hibernation on bone marrow transcriptome in thirteen-lined ground squirrels

Cooper

Sell

Fahrenkrog

et al. 2016

Physiological Genomics

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“…This virus is included on the list of agents screened before bone marrow transplantation in the United States (http://www.guideline.gov/summary/summary.aspx?doc_id=2573&nbr=1799&string=pertussis). Prolonged viremia observed in humans and rodents is due to the intraerythrocytic location of virions, which protects them from immune clearance ( 12 – 14 ). …”

Section: Coltivirusesmentioning

confidence: 99%

Coltiviruses and Seadornaviruses in North America, Europe, and Asia

Attoui

Jaafar

Micco

et al. 2005

Emerg. Infect. Dis.

103

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“…Physiological adjustments associated with deep torpor can result in a decreased primary [30] and secondary [28], [31] humoral response, an absence of T and B lymphocyte proliferative ability [26], and a decrease in serum complement protein activity [24]. Torpor can also result in increased rates of infection [32], [33], [34] or decreased levels of infection [30], [34], [35], presumably depending on optimal growth conditions of the invading parasite. For example, experimentally introduced nematodes ( Trichinella spiralis ) rarely develop into adults in bats held at 26°C or below.…”

Section: Introductionmentioning

confidence: 99%

Specific Alterations in Complement Protein Activity of Little Brown Myotis (Myotis lucifugus) Hibernating in White-Nose Syndrome Affected Sites

et al. 2011

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White-nose syndrome (WNS) is the most devastating condition ever reported for hibernating bats, causing widespread mortality in the northeastern United States. The syndrome is characterized by cutaneous lesions caused by a recently identified psychrophilic and keratinophylic fungus (Geomyces destructans), depleted fat reserves, atypical behavior, and damage to wings; however, the proximate cause of mortality is still uncertain. To assess relative levels of immunocompetence in bats hibernating in WNS-affected sites compared with levels in unaffected bats, we describe blood plasma complement protein activity in hibernating little brown myotis (Myotis lucifugus) based on microbicidal competence assays using Escherichia coli, Staphylococcus aureus and Candida albicans. Blood plasma from bats collected during mid-hibernation at WNS-affected sites had higher bactericidal ability against E. coli and S. aureus, but lower fungicidal ability against C. albicans when compared with blood plasma from bats collected at unaffected sites. Within affected sites during mid-hibernation, we observed no difference in microbicidal ability between bats displaying obvious fungal infections compared to those without. Bactericidal ability against E. coli decreased significantly as hibernation progressed in bats collected from an affected site. Bactericidal ability against E. coli and fungicidal ability against C. albicans were positively correlated with body mass index (BMI) during late hibernation. We also compared complement activity against the three microbes within individuals and found that the ability of blood plasma from hibernating M. lucifugus to lyse microbial cells differed as follows: E. coli>S. aureus>C. albicans. Overall, bats affected by WNS experience both relatively elevated and reduced innate immune responses depending on the microbe tested, although the cause of observed immunological changes remains unknown. Additionally, considerable trade-offs may exist between energy conservation and immunological responses. Relationships between immune activity and torpor, including associated energy expenditure, are likely critical components in the development of WNS.

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Colorado Tick Fever: Prolonged Viremia in Hibernating Citellus Lateralis *

Cited by 19 publications

References 0 publications

Effects of hibernation on bone marrow transcriptome in thirteen-lined ground squirrels

Effects of hibernation on bone marrow transcriptome in thirteen-lined ground squirrels

Coltiviruses and Seadornaviruses in North America, Europe, and Asia

Specific Alterations in Complement Protein Activity of Little Brown Myotis (Myotis lucifugus) Hibernating in White-Nose Syndrome Affected Sites

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