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Defolie C, Merkling T, Fichtel C. Patterns and variation in the mammal parasite-glucocorticoid relationship. Biol Rev Camb Philos Soc 2020; 95:74-93. [PMID: 31608587 DOI: 10.1111/brv.12555] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 08/23/2019] [Accepted: 09/03/2019] [Indexed: 01/24/2023]
Abstract
Parasites are ubiquitous and can strongly affect their hosts through mechanisms such as behavioural changes, increased energetic costs and/or immunomodulation. When parasites are detrimental to their hosts, they should act as physiological stressors and elicit the release of glucocorticoids. Alternatively, previously elevated glucocorticoid levels could facilitate parasite infection due to neuroimmunomodulation. However, results are equivocal, with studies showing either positive, negative or no relationship between parasite infection and glucocorticoid levels. Since factors such as parasite type, infection severity or host age and sex can influence the parasite-glucocorticoid relationship, we review the main mechanisms driving this relationship. We then perform a phylogenetic meta-analysis of 110 records from 65 studies in mammalian hosts from experimental and observational studies to quantify the general direction of this relationship and to identify ecological and methodological drivers of the observed variability. Our review produced equivocal results concerning the direction of the relationship, but there was stronger support for a positive relationship, although causality remained unclear. Mechanisms such as host manipulation for parasite survival, host response to infection, cumulative effects of multiple stressors, and neuro-immunomodulatory effects of glucocorticoids could explain the positive relationship. Our meta-analysis results revealed an overall positive relationship between glucocorticoids and parasitism among both experimental and observational studies. Because all experimental studies included were parasite manipulations, we conclude that parasites caused in general an increase in glucocorticoid levels. To obtain a better understanding of the directionality of this link, experimental manipulation of glucocorticoid levels is now required to assess the causal effects of high glucocorticoid levels on parasite infection. Neither parasite type, the method used to assess parasite infection nor phylogeny influenced the relationship, and there was no evidence for publication bias. Future studies should attempt to be as comprehensive as possible, including moderators potentially influencing the parasite-glucocorticoid relationship. We particularly emphasise the importance of testing hosts of a broad age range, concomitantly measuring sex hormone levels or at least reproductive status, and for observational studies, also considering food availability, host body condition and social stressors to obtain a better understanding of the parasite-glucocorticoid relationship.
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Affiliation(s)
- Charlotte Defolie
- Sociobiology/Anthropology Department, University of Göttingen, Kellnerweg 6, 37077, Göttingen, Germany.,Behavioral Ecology & Sociobiology Unit, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077, Göttingen, Germany.,Leibniz ScienceCampus "Primate Cognition", German Primate Center, Kellnerweg 4, 37077, Göttingen, Germany
| | - Thomas Merkling
- Department of Natural Resource Sciences, McGill University, Macdonald-Stewart Building, 21111 Lakeshore Road, Ste. Anne de Bellevue, Québec, H9X 3V9, Canada
| | - Claudia Fichtel
- Behavioral Ecology & Sociobiology Unit, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077, Göttingen, Germany.,Leibniz ScienceCampus "Primate Cognition", German Primate Center, Kellnerweg 4, 37077, Göttingen, Germany
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Ribeiro CR, Gonçalves CA, Cruz LM, Galera PD. PREVALÊNCIA DA LEISHMANIOSE VISCERAL CANINA E COINFECÇÕES EM REGIÃO PERIURBANA NO DISTRITO FEDERAL – BRASIL. CIÊNCIA ANIMAL BRASILEIRA 2019. [DOI: 10.1590/1089-6891v20e-49589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Resumo Objetivou-se verificar a prevalência da leishmaniose visceral canina (LVC) em área periurbana com foco de transmissão no Distrito Federal (DF) e também avaliar a prevalência de coinfecções como dirofilariose, anaplasmose, erliquiose e doença de Lyme em cães sororreagentes para LVC. Inicialmente, amostras de soros dos cães da área de estudo foram testadas à reação imunocromatográfica que contém dois antígenos recombinantes ̶ rK39 e rK26 − (DPP) para Leishmania sp. O soro dos animais reagentes ao teste de DPP foi confirmado para LVC com ELISA. As amostras reagentes a ambos os testes foram analisadas para possíveis coinfecções através do teste de SNAP (IDEXX 4Dx Plus). Foram avaliados 240 cães, dos quais 132 (55%) obtiveram resultados reagentes para DPP e para ELISA concomitantemente, sendo diagnosticados com LVC. Destes, 26 (20%) foram reagentes para Ehrlichia canis ou E. ewangii, 9 (7%) apresentaram positividade para Anaplasma phagocytophilum ou A. platys e, nessas amostras que se apresentaram reagentes, observou-se a ocorrência de coinfecção de anaplasmose, erliquiose e leishmaniose em 3 (2,3%) animais. Verificou-se alta prevalência da LVC na região periurbana do DF, destacando-se a necessidade de diagnóstico mais preciso quanto a coinfecções que possivelmente podem influenciar no prognóstico e manifestação do quadro clínico desses pacientes.
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Parreira DR, Jansen AM, Abreu UGP, Macedo GC, Silva ARS, Mazur C, Andrade GB, Herrera HM. Health and epidemiological approaches of Trypanosoma evansi and equine infectious anemia virus in naturally infected horses at southern Pantanal. Acta Trop 2016; 163:98-102. [PMID: 27497875 DOI: 10.1016/j.actatropica.2016.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 08/03/2016] [Accepted: 08/03/2016] [Indexed: 11/19/2022]
Abstract
Equine infectious anemia virus (EIAV) and Trypanossoma evansi are endemic in Brazilian Pantanal Biome, an important area for livestock production. In this sense, we evaluated the epidemiological single and co-infection effects of T. evansi and EIAV in naturally infected horses in the southern Pantanal wetland by serological tests and hematological assays. Both higher seroprevalence and heath poor condition of the sampled animals were associated with differences in horse management between farms. We found that the negative animals for both infectious agents (NN) represented the major group in F1 (37%), and the smallest group in F2 (19%). Furthermore, we recorded higher EIAV seroprevalence (56%) in F2, compared to F1 (38%). We observed that T. evansi infection was mostly related to young horses, as seen by their higher seroprevalence, ranging from 70.7% in the beginning of the rainy season to 81% in the end of flood period, in comparison with the values of 42% and 68%, respectively, in working animals. on the other hand, working animals showed a higher seroprevalence for EIAV (48%) in both seasons than young horses. We observed that the management of working horses could be a risk factor of EIAV infection. On the other hand, as T. evansi is maintained in the study region by many species of wild mammals, the mechanical transmission through blood-sucking vectors ensures the infection to horses since early. Our results showed that single or co-infection by EIAV and T. evansi caused different degree of anemia in the infected animals. Moreover, the health of horses in Brazilian Pantanal is also influenced by differences in horse management and environmental circumstances.
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Affiliation(s)
| | - Ana M Jansen
- Fundação Oswaldo Cruz - FIOCRUZ, Rio de Janeiro, CEP 21040-900, Brazil
| | - Urbano G P Abreu
- Empresa Brasileira de Pesquisa Agropecuária - EMBRAPA Pantanal, Corumbá, CEP 79320-900, Brazil
| | - Gabriel C Macedo
- Universidade Católica Dom Bosco - UCDB, Campo Grande, CEP 79117-900, Brazil
| | - Antônia R S Silva
- Universidade Federal Rural do Rio de Janeiro - UFRRJ, Seropédica, CEP 23890-000, Brazil
| | - Carlos Mazur
- Universidade Federal Rural do Rio de Janeiro - UFRRJ, Seropédica, CEP 23890-000, Brazil
| | - Gisele B Andrade
- Universidade Católica Dom Bosco - UCDB, Campo Grande, CEP 79117-900, Brazil
| | - Heitor M Herrera
- Universidade Católica Dom Bosco - UCDB, Campo Grande, CEP 79117-900, Brazil.
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Hull R, Dlamini Z. The role played by alternative splicing in antigenic variability in human endo-parasites. Parasit Vectors 2014; 7:53. [PMID: 24472559 PMCID: PMC4015677 DOI: 10.1186/1756-3305-7-53] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 01/17/2014] [Indexed: 01/03/2023] Open
Abstract
Endo-parasites that affect humans include Plasmodium, the causative agent of malaria, which remains one of the leading causes of death in human beings. Despite decades of research, vaccines to this and other endo-parasites remain elusive. This is in part due to the hyper-variability of the parasites surface proteins. Generally these surface proteins are encoded by a large family of genes, with only one being dominantly expressed at certain life stages. Another layer of complexity can be introduced through the alternative splicing of these surface proteins. The resulting isoforms may differ from each other with regard to cell localisation, substrate affinities and functions. They may even differ in structure to the extent that they are no longer recognised by the host’s immune system. In many cases this leads to changes in the N terminus of these proteins. The geographical localisation of endo-parasitic infections around the tropics and the highest incidences of HIV-1 infection in the same areas, adds a further layer of complexity as parasitic infections affect the host immune system resulting in higher HIV infection rates, faster disease progression, and an increase in the severity of infections and complications in HIV diagnosis. This review discusses some examples of parasite surface proteins that are alternatively spliced in trypanosomes, Plasmodium and the parasitic worm Schistosoma as well as what role alternate splicing may play in the interaction between HIV and these endo-parasites.
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Affiliation(s)
| | - Zodwa Dlamini
- University of South Africa, College of Agriculture and Environmental Sciences, College of Agriculture and Environmental Sciences, C/o Christiaan de Wet and Pioneer Avenue, Private Bag X6, Florida Science Campus, Florida, Johannesburg 1710, South Africa.
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Barratt JLN, Harkness J, Marriott D, Ellis JT, Stark D. Importance of nonenteric protozoan infections in immunocompromised people. Clin Microbiol Rev 2010; 23:795-836. [PMID: 20930074 PMCID: PMC2952979 DOI: 10.1128/cmr.00001-10] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
There are many neglected nonenteric protozoa able to cause serious morbidity and mortality in humans, particularly in the developing world. Diseases caused by certain protozoa are often more severe in the presence of HIV. While information regarding neglected tropical diseases caused by trypanosomatids and Plasmodium is abundant, these protozoa are often not a first consideration in Western countries where they are not endemic. As such, diagnostics may not be available in these regions. Due to global travel and immigration, this has become an increasing problem. Inversely, in certain parts of the world (particularly sub-Saharan Africa), the HIV problem is so severe that diseases like microsporidiosis and toxoplasmosis are common. In Western countries, due to the availability of highly active antiretroviral therapy (HAART), these diseases are infrequently encountered. While free-living amoebae are rarely encountered in a clinical setting, when infections do occur, they are often fatal. Rapid diagnosis and treatment are essential to the survival of patients infected with these organisms. This paper reviews information on the diagnosis and treatment of nonenteric protozoal diseases in immunocompromised people, with a focus on patients infected with HIV. The nonenteric microsporidia, some trypanosomatids, Toxoplasma spp., Neospora spp., some free-living amoebae, Plasmodium spp., and Babesia spp. are discussed.
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Affiliation(s)
- J L N Barratt
- Department of Microbiology, St. Vincent's Hospital, Darlinghurst 2010, NSW, Australia.
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WILLIAMS PAULD, DAY TROY. Epidemiological and evolutionary consequences of targeted vaccination. Mol Ecol 2008; 17:485-99. [DOI: 10.1111/j.1365-294x.2007.03418.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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