Parasite immune evasion and manipulation of host phenotype

2021 ◽  
pp. 183-212
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Immune Evasion ◽  
Molecular Mimicry ◽  
Final Host ◽  
Immune Defence ◽  
Intermediate Hosts ◽  
Transmission Success ◽  
Duration Of Infection ◽  
Neuronal Systems ◽  
Host Behaviour ◽  
Immune Defences

All parasites manipulate their hosts by interference with immune defences and host behaviour. Passive evasion, for example, is by molecular mimicry or by changing surfaces. Active interference involves production of molecules that block or modify host immune defence regulation or affect metabolism and neuronal systems. All steps of the immune defence cascades are attacked by parasites, including the microbiota. Manipulation can increase the duration of infection or transmission success. The latter is particularly prominent in intermediate hosts that need to be consumed by a final host. Host fecundity reduction and gigantism provide extra resources for the parasite. Theory can predict what manipulation should be best; conflicts arise among co-infecting parasites.

Investigations of the unimiracidial infection ofSchistosoma intercalatumin snails and the infection of the final host using cercariae of one sex

1977 ◽  
Vol 51 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Flemming Frandsen
Keyword(s):  
Final Host ◽  
Intermediate Hosts ◽  
Male And Female ◽  
Single Sex ◽  
Cercarial Production ◽  
Duration Of Infection ◽  
Different Populations ◽  
Schistosoma Intercalatum

ABSTRACTInfection with single miracidial doses ofSchistosoma intercalatumfrom Cameroun inBulinus forskaliiand from Zaïre inB. globosusresulted in an equal number of male and female infections. The cercarial production of both sexes started at the same time. The male infected snails produced a greater number of cercariae, because of the longer duration of infection.The recovery of schistosomes from infection with male and female cercariae was forS. intercalatum, Zaïre, 38·8 ± 10·6 and 18·7 ± 14·0 respectively.ForS. intercalatumfrom Cameroun, with single sex cercariae from two different populations of intermediate hosts from Zaïre and Cameroun were 38·3 ± 7·3 (♂); 20·3 ± 9·3 (♀) and 35·0 ± 8·7 (♂); 12·2 ± 4·5 (♀), respectively.

scholarly journals Altered host behaviour and brain serotonergic activity caused by acanthocephalans: evidence for specificity

2006 ◽  
Vol 273 (1605) ◽  
pp. 3039-3045 ◽  
Author(s):  
Luke Tain ◽  
Marie-Jeanne Perrot-Minnot ◽  
Frank Cézilly
Keyword(s):  
Final Host ◽  
Gammarus Pulex ◽  
Intermediate Hosts ◽  
Pomphorhynchus Laevis ◽  
Serotonergic Activity ◽  
Specific Behaviour ◽  
Host Behaviour ◽  
By Products

Manipulative parasites can alter the phenotype of intermediate hosts in various ways. However, it is unclear whether such changes are just by-products of infection or adaptive and enhance transmission to the final host. Here, we show that the alteration of serotonergic activity is functionally linked to the alteration of specific behaviour in the amphipod Gammarus pulex infected with acanthocephalan parasites. Pomphorhynchus laevis and, to a lesser extent, Pomphorhynchus tereticollis altered phototactism, but not geotactism, in G. pulex , whereas the reverse was true for Polymorphus minutus . Serotonin (5-hydroxytryptamine, 5-HT) injected to uninfected G. pulex mimicked the altered phototactism, but had no effect on geotactism. Photophilic G. pulex infected with P. laevis or P. tereticollis showed a 40% increase in brain 5-HT immunoreactivity compared to photophobic, uninfected individuals. In contrast, brain 5-HT immunoreactivity did not differ between P. minutus -infected and uninfected G. pulex . Finally, brain 5-HT immunoreactivity differed significantly among P. tereticollis -infected individuals in accordance with their degree of manipulation. Our results demonstrate that altered 5-HT activity is not the mere consequence of infection by acanthocephalans but is specifically linked to the disruption of host photophobic behaviour, whereas the alteration of other behaviours such as geotactism may rely on distinct physiological routes.

scholarly journals The secretome of a parasite alters its host's behaviour but does not recapitulate the behavioural response to infection

2020 ◽  
Vol 287 (1925) ◽  
pp. 20200412 ◽  
Author(s):  
Chloé Suzanne Berger ◽  
Nadia Aubin-Horth
Keyword(s):  
Gasterosteus Aculeatus ◽  
Final Host ◽  
Life Cycles ◽  
Avian Host ◽  
Allopatric Population ◽  
Late Infection ◽  
Intermediate Hosts ◽  
Behavioural Changes ◽  
Host Parasite ◽  
Host Behaviour

Parasites with complex life cycles have been proposed to manipulate the behaviour of their intermediate hosts to increase the probability of reaching their final host. The cause of these drastic behavioural changes could be manipulation factors released by the parasite in its environment (the secretome), but this has rarely been assessed. We studied a non-cerebral parasite, the cestode Schistocephalus solidus , and its intermediate host, the threespine stickleback ( Gasterosteus aculeatus ), whose response to danger becomes significantly diminished when infected. These altered behaviours appear only during late infection, when the worm is ready to reproduce in its final avian host. Sympatric host–parasite pairs show higher infection success for parasites, suggesting that the secretome effects could differ for allopatric host–parasite pairs with independent evolutionary histories. We tested the effects of secretome exposure on behaviour by using secretions from the early and late infection of S. solidus and by injecting them in healthy sticklebacks from a sympatric and allopatric population. Contrary to our prediction, secretome from late infection worms did not result in more risky behaviours, but secretome from early infection resulted in more cautious hosts, only in fish from the allopatric population. Our results suggest that the secretome of S. solidus contains molecules that can affect host behaviour, that the causes underlying the behavioural changes in infected sticklebacks are multifactorial and that local adaptation between host–parasite pairs may extend to the response to the parasite's secretome content.

Costs of intraspecific and interspecific host sharing in acanthocephalan cystacanths

Parasitology ◽  
2001 ◽  
Vol 122 (4) ◽  
pp. 483-489 ◽  
Author(s):  
B. S. DEZFULI ◽  
L. GIARI ◽  
R. POULIN
Keyword(s):  
Intermediate Host ◽  
Definitive Host ◽  
Interspecific Interactions ◽  
Sympatric Species ◽  
Competitive Interactions ◽  
Host Size ◽  
Intermediate Hosts ◽  
Transmission Success ◽  
Additional Costs ◽  
Net Benefits

Larval helminths often share individual intermediate hosts with other larval worms of the same or different species. In the case of immature acanthocephalans capable of altering the phenotype of their intermediate hosts, the benefits or costs of host sharing can be evaluated in terms of increased or decreased probability of transmission to a suitable definitive host. Competitive interactions among the immature stages of acanthocephalans within the intermediate host could create additional costs of host sharing, however. The effects of intraspecific and interspecific interactions were measured in 3 sympatric species of acanthocephalans exploiting a population of the amphipod Echinogammarus stammeri in the River Brenta, Italy. The strength of interactions was assessed from differences in the size achieved by infective cystacanths in the intermediate host. The size of Pomphorhynchus laevis cystacanths was not correlated with host size, whereas the size of Acanthocephalus clavula and Polymorphus minutus cystacanths increased with host size. Reductions in cystacanth size caused by intraspecific competition were only detected in P. laevis, but may also occur in both A. clavula and P. minutus. When co-occurring in the same amphipod with cystacanths of A. clavula, cystacanths of P. laevis attained a smaller size than when they occurred on their own. This effect was not reciprocal, with the size of A. clavula cystacanths not being affected. This supports earlier suggestions that it is adaptive for A. clavula to associate with P. laevis in amphipod intermediate hosts, with both species going to the same fish definitive hosts. In contrast, cystacanths of P. laevis achieved their largest size when they co-occurred in an amphipod with a cystacanth of P. minutus, which has a different definitive host (i.e. birds). These findings suggest that the net benefits of sharing an intermediate host can only be estimated by taking into account both the effects on transmission success and the consequences for cystacanth development.

Insights into the molecular basis of host behaviour manipulation by Toxoplasma gondii infection

2017 ◽  
Vol 1 (6) ◽  
pp. 563-572 ◽  
Author(s):  
Pierre-Mehdi Hammoudi ◽  
Dominique Soldati-Favre
Keyword(s):  
Toxoplasma Gondii ◽  
Stress Responses ◽  
Molecular Mechanisms ◽  
Brain Regions ◽  
Intermediate Hosts ◽  
Toxoplasma Gondii Infection ◽  
Host Parasite ◽  
Host Behaviour ◽  
The Brain ◽  
Brain Homeostasis

Typically illustrating the ‘manipulation hypothesis’, Toxoplasma gondii is widely known to trigger sustainable behavioural changes during chronic infection of intermediate hosts to enhance transmission to its feline definitive hosts, ensuring survival and dissemination. During the chronic stage of infection in rodents, a variety of neurological dysfunctions have been unravelled and correlated with the loss of cat fear, among other phenotypic impacts. However, the underlying neurological alteration(s) driving these behavioural modifications is only partially understood, which makes it difficult to draw more than a correlation between T. gondii infection and changes in brain homeostasis. Moreover, it is barely known which among the brain regions governing fear and stress responses are preferentially affected during T. gondii infection. Studies aiming at an in-depth dissection of underlying molecular mechanisms occurring at the host and parasite levels will be discussed in this review. Addressing this reminiscent topic in the light of recent technical progress and new discoveries regarding fear response, olfaction and neuromodulator mechanisms could contribute to a better understanding of this complex host–parasite interaction.

A proposed three-host life history of Monascusfiliformis (Rudolphi, 1819) (Digenea: Fellodi-stomidae) in the southwest Atlantic Ocean

1998 ◽  
Vol 76 (6) ◽  
pp. 1198-1203 ◽  
Author(s):  
SR Martorelli ◽  
F Cremonte
Keyword(s):  
Life Cycle ◽  
Atlantic Ocean ◽  
General Pattern ◽  
First Record ◽  
Final Host ◽  
Full Description ◽  
Intermediate Hosts ◽  
Southwest Atlantic ◽  
Experimental Scheme ◽  
The North

This is the first record of cercariae of Monascus filiformis (Rudolphi, 1819) and of Chaetognatha as a secondintermediate host in the southwest Atlantic Ocean. The morphology of the sporocyst and cercaria from Nucula obliqua (Bivalvia:Nuculidae) and a full description of the metacercaria from hydromedusae are given. The life cycle of M. filiformis involves threehosts. The bivalve N. obliqua is the first intermediate host, Chaetognatha and medusae are the second intermediate hosts, and thejurel Trachurus lathami (Pisces: Carangidae) is the final host. The life cycle of M. filiformis occurs in shallow waters in theArgentine Sea and differs from Køie’s experimental scheme for the North Sea in the addition of planktonic invertebrates assecond intermediate hosts. The life cycle proposed here follows the general pattern given for the family Fellodistomidae.

scholarly journals Poxvirus Targeting of E3 Ligase β-TrCP by Molecular Mimicry: A Mechanism to Inhibit NF-κB Activation and Promote Immune Evasion and Virulence

2013 ◽  
Vol 9 (2) ◽  
pp. e1003183 ◽  
Author(s):  
Daniel S. Mansur ◽  
Carlos Maluquer de Motes ◽  
Leonie Unterholzner ◽  
Rebecca P. Sumner ◽  
Brian J. Ferguson ◽  
...  
Keyword(s):  
Immune Evasion ◽  
Molecular Mimicry ◽  
E3 Ligase

scholarly journals The helminth infracommunities of the wood mouse (Apodemus sylvaticus) two years after the fire in Mediterranean forests

2013 ◽  
Vol 50 (1) ◽  
pp. 27-38 ◽  
Author(s):  
I. Torre ◽  
A. Arrizabalaga ◽  
C. Feliu ◽  
A. Ribas
Keyword(s):  
Species Richness ◽  
Life Cycle ◽  
Wood Mouse ◽  
Final Host ◽  
Life Cycles ◽  
Helminth Species ◽  
Mediterranean Forests ◽  
Intermediate Hosts ◽  
Wood Mice ◽  
Short Period

AbstractParasites have been recognized as indicators for natural or man-induced environmental stress and perturbation. In this article, we investigated the role of two non-exclusive hypotheses on the response of helminths of wood mice to fire perturbation: 1) a reduction of the helminth infracommunity (species richness) in post-fire areas due to the temporal lack of worms with indirect (complex) life cycles linked to intermediate hosts that are more specialized than the final host, and 2) an increase of the abundance of helminths with direct (simple) life cycles as a response of increasing abundances of the final host, may be in stressful conditions linked to the post-fire recolonization process.We studied the helminth infracommunities of 97 wood mice in two recently burned plots (two years after the fire) and two control plots in Mediterranean forests of NE Spain. Species richness of helminths found in control plots (n = 14) was twice large than in burned ones (n = 7). Six helminth species were negatively affected by fire perturbation and were mainly or only found in unburned plots. Fire increased the homogeneity of helminth infracommunities, and burned plots were characterised by higher dominance, and higher parasitation intensity. We found a gradient of frequency of occurrence of helminth species according to life cycle complexity in burned areas, being more frequent monoxenous (66.6 %), than diheteroxenous (33.3 %) and triheteroxenous (0 %), confirming the utility of helminths as bioindicators for ecosystem perturbations. Despite the short period studied, our results pointed out an increase in the abundance and prevalence of some direct life cycle helminths in early postfire stages, whereas indirect life cycle helminths were almost absent. A mismatch between the final host (that showed a fast recovery shortly after the fire), and the intermediate hosts (that showed slow recoveries shortly after the fire), was responsible for the loss of half of the helminth species.

scholarly journals Immune Evasion Strategies of Schistosomes

2021 ◽  
Vol 11 ◽  
Author(s):  
Jacob R. Hambrook ◽  
Patrick C. Hanington
Keyword(s):  
Immune Evasion ◽  
Immune Cell ◽  
Molecular Mimicry ◽  
Life Cycles ◽  
Host Responses ◽  
Immune Recognition ◽  
Factors Affecting ◽  
Cell Functions ◽  
Treatment Plans ◽  
Host Parasite

Human schistosomes combat the unique immune systems of two vastly different hosts during their indirect life cycles. In gastropod molluscs, they face a potent innate immune response composed of variable immune recognition molecules and highly phagocytic hemocytes. In humans, a wide variety of innate and adaptive immune processes exist in proximity to these parasites throughout their lifespan. To survive and thrive as the second most common parasitic disease in humans, schistosomes have evolved many techniques to avoid and combat these targeted host responses. Among these techniques are molecular mimicry of host antigens, the utilization of an immune resistant outer tegument, the secretion of several potent proteases, and targeted release of specific immunomodulatory factors affecting immune cell functions. This review seeks to describe these key immune evasion mechanisms, among others, which schistosomes use to survive in both of their hosts. After diving into foundational observational studies of the processes mediating the establishment of schistosome infections, more recent transcriptomic and proteomic studies revealing crucial components of the host/parasite molecular interface are discussed. In order to combat this debilitating and lethal disease, a comprehensive understanding of schistosome immune evasion strategies is necessary for the development of novel therapeutics and treatment plans, necessitating the discussion of the numerous ways in which these parasitic flatworms overcome the immune responses of both hosts.

Infection of the lower urinary tract

2018 ◽  
Author(s):  
Ased Ali ◽  
Rob Pickard
Keyword(s):  
Urinary Tract ◽  
Lower Urinary Tract ◽  
Asymptomatic Bacteriuria ◽  
Immune Defence ◽  
Lower Urinary Tract Infection ◽  
Sexually Transmitted ◽  
Level Of Invasion ◽  
Duration Of Infection ◽  
Lower Urinary

Lower urinary tract infection is common, distressing, and when recurrent can have a significant impact on quality of life. The normally sterile urinary tract is the site of an ongoing but complex interplay between an evolving pathogen and a highly developed host immune defence system. The development of an active infection generally requires either greater virulence in the pathogen or deficient host immune defence. Nonetheless, even where infection has occurred, the interplay between pathogen and host continues, influencing the extent and level of invasion as well as the duration of infection and extent of tissue damage caused.Asymptomatic bacteriuria is discussed, with implications for treatment (usually not). The risk factors, diagnosis and management of simple cystitis are discussed, with a discussion of approaches to managing recurrent infections. Urethritis requires consideration of sexually transmitted infections and co-infections. Prostatitis requires more prolonged antibiotic treatment.

Sign in / Sign up

Export Citation Format

Share Document