Related Experiment Video
Updated: Jun 5, 2026
08:24
Inoculating Anopheles gambiae Mosquitoes with Beads to Induce and Measure the Melanization Immune Response
Published on: January 12, 2017
Strong density-dependent competition and acquired immunity constrain parasite establishment: implications for
Lien T Luong1, Beth A Vigliotti, Peter J Hudson
1Center for Infectious Disease Dynamics, Department of Biology, 208 Mueller Laboratory, The Pennsylvania State University, University Park, PA 16802, USA. ltl1@psu.edu
International Journal for Parasitology
|January 11, 2011
Summary
Parasite distribution in white-footed mice is random, unlike most parasites. Density-dependent competition and acquired immunity prevent parasite buildup, explaining this unique pattern.
Area of Science:
- Ecology
- Parasitology
- Evolutionary Biology
Background:
- Most parasites aggregate in host populations, with few hosts heavily infected.
- The trophically transmitted parasite Pterygodermatites peromysci in white-footed mice shows random distribution, an exception to the aggregation rule.
Purpose of the Study:
- Investigate factors causing random parasite distribution in P. peromysci.
- Test the hypothesis that density-dependent processes limit parasite establishment and survival.
Main Methods:
- Conducted primary and challenge infections in laboratory mice.
- Assessed parasite establishment, survival, worm length, and host immune response (IgG levels).
Main Results:
- Parasite establishment showed a dose-dependent constraint, decreasing at high parasite doses.
- Increased exposure led to shorter worm length, indicating density-dependent competition.
- Challenge infections revealed lower prevalence and intensity, with density-dependent acquired immunity.
Conclusions:
- Intra-specific competition and acquired host immunity act in a density-dependent manner.
- These factors constrain parasite establishment and survival, preventing aggregation.
- This explains the random distribution of P. peromysci in white-footed mice.
Related Concept Videos
01:22Microbial Interactions: Parasitism
Parasitism is a form of microbial interaction in which parasitic microbes exploit a host organism for nutrients and shelter, often at the host's expense. Unlike mutualistic relationships, where both organisms benefit, parasitism benefits only the parasite and harms the host.Classification of ParasitesMicrobial parasites are broadly classified based on their location relative to the host.Ectoparasites remain on the host’s surface, such as the skin or outer tissues, drawing nutrients...
01:29Malaria
Malaria pathogenesis in humans reflects a delicate interplay between parasite biology and host response. Clinical illness reflects a host’s immune response to the parasite’s asexual replication cycle, which is often asymptomatic in individuals with partial immunity. From the parasite's perspective, transmission between mosquito and human with minimal host pathology is evolutionarily advantageous. Among the six Plasmodium species infecting humans, P. falciparum and P. vivax dominate in global...
01:25Colonisation of Pathogens
Pathogen colonization of host tissues is a critical step in the development of infectious diseases. Various pathogenic microorganisms, including bacteria, fungi, viruses, and protozoa, have evolved complex strategies to attach to, invade, and persist within host environments. These mechanisms enable pathogens to establish infections, evade immune responses, and resist antimicrobial treatments.Attachment to Host CellsIn bacteria, colonization typically begins with adherence to host epithelial...
01:26Microbial Interactions: Competition
Microbial competition is an ecological interaction in which microorganisms vie for limited resources within shared environments. These resources may include nutrients, space, or light, depending on the system. The intensity and outcome of competition are influenced by the environmental context, such as nutrient availability, spatial constraints, and the diversity of microbial species present. These competitive interactions significantly influence the structure, function, and resilience of...
00:58Symbiosis
Symbiotic relationships are long-term, close interactions between individuals of different species that affect the distribution and abundance of those species. When a relationship is beneficial to both species, this is called mutualism. When the relationship is beneficial to one species but neither beneficial nor harmful to the other species, this is called commensalism. When one organism is harmed to benefit another, the relationship is known as parasitism. These types of relationships often...
02:34Competition
When organisms require the same limited resources within an environment, they may have to compete for them. Competition is a net-negative interaction. Even if two competing individuals or populations do not interact directly, the overall fitness of both competitors is lowered as a result of not having full access to the limited resource.Intraspecific competition, which occurs between individuals of the same species, serves as a natural mechanism for regulating population size. Too much...