scholarly journals Snail host parental investment throughout a Schistosoma mansoni infection

2020 ◽  
Author(s):  
Stephanie O. Gutierrez ◽  
Olivia J. Lockyear ◽  
Dennis J. Minchella
Keyword(s):  
Schistosoma Mansoni ◽  
Parental Investment ◽  
Pathogen Resistance ◽  
Snail Host ◽  
Parasitic Infections ◽  
Infection Prevalence ◽  
Immune Priming ◽  
Investment Theory ◽  
Parent Health ◽  
Fecundity Compensation

AbstractParental investment theory describes the ability of organisms to respond to an environmental challenge by increasing the fitness of future offspring. Utilizing life history changes, organisms can maximize fitness by increasing their total reproductive output or by investing more into the success of fewer offspring. In cases where parasitic infections result in castration of their host, increased reproductive effort known as fecundity compensation has been demonstrated in a variety of organisms. This response appears predictive of expected future reproductive losses. Organisms struggling with an environmental pathogen, may attempt to better prepare their offspring for the environment they are experiencing through transgenerational immune priming (TGIP). In immune priming, primary infection lowers the prevalence and intensity of a subsequent infection by the same pathogen. Transgenerational immune priming carries pathogen resistance into further generations without genotypic changes. The focus of this study was to determine whether invertebrate parental investment into offspring parasite resistance varies over the course of an infection. Utilizing the snail host Biomphalaria glabrata and its trematode parasite Schistosoma mansoni, offspring were reared from specific time intervals in the parent’s infection and subsequently exposed to the same pathogen when each cohort reached the same age- 12 weeks. Differences in infection prevalence and intensity were expected based on when the offspring were born during their parent’s infection. A trade-off was predicted between the number of offspring produced in a cohort and offspring resistance to future infections. Offspring born during the period of fecundity compensation were predicted to exhibit lower resistance due to a dilution of individual investment by parents into a larger offspring pool. While our results did not support TGIP, there were differences in offspring prevalence, as well as an indication that parent health may interact with genetics in offspring resistance. Results suggest that parental condition can influence resistance of B. glabrata offspring to S. mansoni but that TGIP may not be operating in this system.

Ultrastructural analysis of “Sensory” surface nerve endings and “putative” neurotransmitter sites in Schistosoma mansoni Miracidia

1989 ◽  
Vol 47 ◽  
pp. 962-963
Author(s):  
Betty Ruth Jones ◽  
Steve Chi-Tang Pan
Keyword(s):  
Nervous System ◽  
Life Cycle ◽  
Schistosoma Mansoni ◽  
Snail Host ◽  
Complex Life Cycle ◽  
Rational Approach ◽  
Effective Control ◽  
The Social ◽  
Social And Economic Development ◽  
Basic Biology

INTRODUCTION: Schistosomiasis has been described as “one of the most devastating diseases of mankind, second only to malaria in its deleterious effects on the social and economic development of populations in many warm areas of the world.” The disease is worldwide and is probably spreading faster and becoming more intense than the overall research efforts designed to provide the basis for countering it. Moreover, there are indications that the development of water resources and the demands for increasing cultivation and food in developing countries may prevent adequate control of the disease and thus the number of infections are increasing.Our knowledge of the basic biology of the parasites causing the disease is far from adequate. Such knowledge is essential if we are to develop a rational approach to the effective control of human schistosomiasis. The miracidium is the first infective stage in the complex life cycle of schistosomes. The future of the entire life cycle depends on the capacity and ability of this organism to locate and enter a suitable snail host for further development, Little is known about the nervous system of the miracidium of Schistosoma mansoni and of other trematodes. Studies indicate that miracidia contain a well developed and complex nervous system that may aid the larvae in locating and entering a susceptible snail host (Wilson, 1970; Brooker, 1972; Chernin, 1974; Pan, 1980; Mehlhorn, 1988; and Jones, 1987-1988).

scholarly journals Parental investment in child health in sub-Saharan Africa: a cross-national study of health-seeking behaviour

2016 ◽  
Vol 3 (2) ◽  
pp. 150460 ◽  
Author(s):  
Caroline Uggla ◽  
Ruth Mace
Keyword(s):  
Health Status ◽  
Child Health ◽  
Birth Order ◽  
Parental Investment ◽  
Sub Saharan Africa ◽  
Health Seeking Behaviour ◽  
Health Seeking ◽  
Investment Theory ◽  
Parental Investment Theory ◽  
Sub Saharan

Parents face trade-offs between investing in child health and other fitness enhancing activities. In humans, parental investment theory has mostly been examined through the analysis of differential child outcomes, with less emphasis on the actions parents take to further a particular offspring’s condition. Here, we make use of household data on health-seeking for children in a high mortality context where such behaviours are crucial for offspring survival. Using Demographic and Health Survey (DHS) data from 17 sub-Saharan African countries, we examine whether maternal factors (age, health, marital status) and child factors (birth order, health, sex, age) independently influence parental investment in health-seeking behaviours: two preventative behaviours (malaria net use and immunization) and two curative ones (treating fever and diarrhoea). Results indicate that children with lower birth order, older mothers and mothers with better health status have higher odds of investment. The effects of a child’s sex and health status and whether the mother is polygynously married vary depending on the type of health-seeking behaviour (preventative versus curative). We discuss how these results square with predictions from parental investment theory pertaining to the state of mothers and children, and reflect on some potential mechanisms and directions for future research.

Energy constraint exerted by the parasite Schistosoma mansoni on the locomotion of its snail host, Biomphalaria glabrata

1996 ◽  
Vol 74 (4) ◽  
pp. 594-598 ◽  
Author(s):  
Claudia Gérard
Keyword(s):  
Resource Allocation ◽  
Schistosoma Mansoni ◽  
Biomphalaria Glabrata ◽  
Snail Host ◽  
Locomotory Activity ◽  
Patent Period ◽  
Energy Constraint

The consequences of the constraint caused by the parasite Schistosoma mansoni on the locomotory activity of its snail host, Biomphalaria glabrata, were studied during the patent period. Rates of locomotion were determined 6 times per 24-h period for juvenile and adult snails with single-miracidium infections, then compared with those of healthy snails of the same age. The locomotory activity of infected snails was the same during the day and at night, whereas control snails moved less at night than during the day. The locomotion of snails infected when immature was similar to that of the controls during the day and superior at night. The locomotion of snails infected when mature decreased regularly during patency and clearly decreased in comparison with that of healthy snails. The results are interpreted in terms of energy constraint on the mode of resource allocation of the host due to the parasite.

scholarly journals Experimental evolution of insect immune memory versus pathogen resistance

2017 ◽  
Vol 284 (1869) ◽  
pp. 20171583 ◽  
Author(s):  
Imroze Khan ◽  
Arun Prakash ◽  
Deepa Agashe
Keyword(s):  
Secondary Infection ◽  
Pathogen Resistance ◽  
Immune Memory ◽  
High Dose ◽  
Basal Resistance ◽  
Immune Priming ◽  
Resistance To Infection ◽  
Empirical Tests ◽  
Rapid Modulation ◽  
Specific Priming

Under strong pathogen pressure, insects often evolve resistance to infection. Many insects are also protected via immune memory (immune priming), whereby sublethal exposure to a pathogen enhances survival after secondary infection. Theory predicts that immune memory should evolve when the pathogen is highly virulent, or when pathogen exposure is relatively rare. However, there are no empirical tests of these hypotheses, and the adaptive benefits of immune memory relative to direct resistance against a pathogen are poorly understood. To determine the selective pressures and ecological conditions that shape immune evolution, we imposed strong pathogen selection on flour beetle ( Tribolium castaneum ) populations, infecting them with Bacillus thuringiensis (Bt) for 11 generations. Populations injected first with heat-killed and then live Bt evolved high basal resistance against multiple Bt strains. By contrast, populations injected only with a high dose of live Bt evolved a less effective but strain-specific priming response. Control populations injected with heat-killed Bt did not evolve priming; and in the ancestor, priming was effective only against a low Bt dose. Intriguingly, one replicate population first evolved priming and subsequently evolved basal resistance, suggesting the potential for dynamic evolution of different immune strategies. Our work is the first report showing that pathogens can select for rapid modulation of insect priming ability, allowing hosts to evolve divergent immune strategies (generalized resistance versus specific immune memory) with potentially distinct mechanisms.

scholarly journals Predicting frequency distribution and influence of sociodemographic and behavioral risk factors of Schistosoma mansoni infection and analysis of co-infection with intestinal parasites

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Carla V.V. Rollemberg ◽  
Marília M.B.L. Silva ◽  
Karla C. Rollemberg ◽  
Fábio R. Amorim ◽  
Nayanna M.N. Lessa ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Low Income ◽  
Intestinal Parasites ◽  
Kernel Estimation ◽  
Kernel Estimator ◽  
Integrated Approach ◽  
Parasitic Infections ◽  
Behavioral Risk ◽  
Water Contact ◽  
Untreated Water

Geospatial analysis was used to study the epidemiology of <em>Schistosoma mansoni</em>, intestinal parasites and co-infections in an area (Ilha das Flores) in Sergipe, Brazil. We collected individually georeferenced sociodemographic, behavioral and parasitological data from 500 subjects, analyzed them by conventional statistics, and produced risk maps by Kernel estimation. The prevalence rates found were: <em>S. mansoni</em> (24.0%), <em>Trichuris trichiura</em> (54.8%), <em>Ascaris lumbricoides</em> (49.2%), Hookworm (17.6%) and <em>Entamoeba histolytica</em> (7.0%). Only 59/500 (11.8%) individuals did not present any of these infections, whereas 279/500 (55.8%) were simultaneously infected by three or more parasites. We observed associations between <em>S. mansoni</em> infection and various variables such as male gender, being rice farmer or fisherman, low educational level, low income, water contact and drinking untreated water. The Kernel estimator indicated that high-risk areas coincide with the poorest regions of the villages as well as with the part of the villages without an adequate sewage system. We also noted associations between both <em>A. lumbricoides</em> and hookworm infections with low education and low income. <em>A. lumbricoides</em> infection and <em>T. trichiura</em> infection were both associated with drinking untreated water and residential open-air sewage. These findings call for an integrated approach to effectively control multiple parasitic infections.

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