Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (660 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Zygote-containing cysts of sporozoan protozoa. Further development in an oocyst produces small individual infective organisms called sporozoites. Then, depending on the genus, the entire oocyst is called a sporocyst or the oocyst contains multiple sporocysts encapsulating the sporozoites.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Oocyst; Sporocysts; Sporocyst.
Where it fits in the MeSH classification
- Broader topics
- Spores, Protozoan; Life Cycle Stages
- Narrower topics
- Sporozoites
Related concepts
- Sporozoites
Research landscape
PubMed indexes 4,704 records tagged with the MeSH heading “Oocysts” (counts retrieved 2026-10-31). 1,238 of them (26.3%) were published from 2020 onward, and the busiest period so far is 2010-2019 with 2,022 records.
Reviews account for 261 records (5.5%) and meta-analyses for 15. Randomized controlled trials number 91 (1.9%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 71 |
| 2000-2009 | 1,373 |
| 2010-2019 | 2,022 |
| 2020 onward | 1,238 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 261 | 5.5% |
| Meta-analyses | 15 | 0.3% |
| Randomized controlled trials | 91 | 1.9% |
Method: PubMed query "Oocysts"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
Interrogating the Plasmodium Sporozoite Surface: Identification of Surface-Exposed Proteins and Demonstration of Glycosylation on CSP and TRAP by Mass Spectrometry-Based Proteomics [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Malaria parasite infection is initiated by the mosquito-transmitted sporozoite stage, a highly motile invasive cell that targets hepatocytes in the liver for infection.
- Closing excerpt
- Finally, our mass spectrometry data provide the first direct evidence that the Plasmodium surface proteins CSP and TRAP are glycosylated in sporozoites, a finding that could impact the selection of vaccine antigens.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (259 words)
Malaria parasite infection is initiated by the mosquito-transmitted sporozoite stage, a highly motile invasive cell that targets hepatocytes in the liver for infection. A promising approach to developing a malaria vaccine is the use of proteins located on the sporozoite surface as antigens to elicit humoral immune responses that prevent the establishment of infection. Very little of the P. falciparum genome has been considered as potential vaccine targets, and candidate vaccines have been almost exclusively based on single antigens, generating the need for novel target identification. The most advanced malaria vaccine to date, RTS,S, a subunit vaccine consisting of a portion of the major surface protein circumsporozoite protein (CSP), conferred limited protection in Phase III trials, falling short of community-established vaccine efficacy goals. In striking contrast to the limited protection seen in current vaccine trials, sterilizing immunity can be achieved by immunization with radiation-attenuated sporozoites, suggesting that more potent protection may be achievable with a multivalent protein vaccine. Here, we provide the most comprehensive analysis to date of proteins located on the surface of or secreted by Plasmodium falciparum salivary gland sporozoites. We used chemical labeling to isolate surface-exposed proteins on sporozoites and identified these proteins by mass spectrometry. We validated several of these targets and also provide evidence that components of the inner membrane complex are in fact surface-exposed and accessible to antibodies in live sporozoites. Finally, our mass spectrometry data provide the first direct evidence that the Plasmodium surface proteins CSP and TRAP are glycosylated in sporozoites, a finding that could impact the selection of vaccine antigens.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 27128092 · DOI · PMC4851412
Longitudinal analysis of Plasmodium sporozoite motility in the dermis reveals component of blood vessel recognition [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Malaria infection starts with injection of Plasmodium sporozoites by an Anopheles mosquito into the skin of the mammalian host.
- Closing excerpt
- Imaging of sporozoites with mutations in key adhesive proteins highlight the importance of the sporozoite's gliding speed and its ability to modulate adhesive properties for successful exit from the inoculation site.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (138 words)
Malaria infection starts with injection of Plasmodium sporozoites by an Anopheles mosquito into the skin of the mammalian host. How sporozoites locate and enter a blood vessel is a critical, but poorly understood process. In this study, we examine sporozoite motility and their interaction with dermal blood vessels, using intravital microscopy in mice. Our data suggest that sporozoites exhibit two types of motility: in regions far from blood vessels, they exhibit 'avascular motility', defined by high speed and less confinement, while in the vicinity of blood vessels their motility is more constrained. We find that curvature of sporozoite tracks engaging with vasculature optimizes contact with dermal capillaries. Imaging of sporozoites with mutations in key adhesive proteins highlight the importance of the sporozoite's gliding speed and its ability to modulate adhesive properties for successful exit from the inoculation site.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 26271010 · DOI · PMC4594146
CRISPR/Cas9 -mediated gene knockout of Anopheles gambiae FREP1 suppresses malaria parasite infection [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Plasmodium relies on numerous agonists during its journey through the mosquito vector, and these agonists represent potent targets for transmission-blocking by either inhibiting or interfering with them pre- or post-transcriptionally.
- Closing excerpt
- FREP1 inactivation, however, resulted in fitness costs including a significantly lower blood-feeding propensity, fecundity and egg hatching rate, a retarded pupation time, and reduced longevity after a blood meal.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (158 words)
Plasmodium relies on numerous agonists during its journey through the mosquito vector, and these agonists represent potent targets for transmission-blocking by either inhibiting or interfering with them pre- or post-transcriptionally. The recently developed CRISPR/Cas9-based genome editing tools for Anopheles mosquitoes provide new and promising opportunities for the study of agonist function and for developing malaria control strategies through gene deletion to achieve complete agonist inactivation. Here we have established a modified CRISPR/Cas9 gene editing procedure for the malaria vector Anopheles gambiae, and studied the effect of inactivating the fibrinogen-related protein 1 (FREP1) gene on the mosquito's susceptibility to Plasmodium and on mosquito fitness. FREP1 knockout mutants developed into adult mosquitoes that showed profound suppression of infection with both human and rodent malaria parasites at the oocyst and sporozoite stages. FREP1 inactivation, however, resulted in fitness costs including a significantly lower blood-feeding propensity, fecundity and egg hatching rate, a retarded pupation time, and reduced longevity after a blood meal.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 29518156 · DOI · PMC5843335
Expelling of Plasmodium falciparum Sporozoites by Anopheles stephensi Mosquitoes During Repeated Feeding [4]
Abstract reading summary — source excerpts
- Opening excerpt
- It is currently unclear whether repeated mosquito feeding attempts achieve pathogen transmission.
- Closing excerpt
- We conclude that repeated feeding results in repeated sporozoite inoculation at similar intensity.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (105 words)
It is currently unclear whether repeated mosquito feeding attempts achieve pathogen transmission. We measured Plasmodium falciparum sporozoite expelling in Anopheles stephensi mosquitoes during 2 interrupted feeding attempts. The number of expelled sporozoites was positively correlated with salivary gland sporozoite load during the first feeding effort (ρ = 0.36, P = .0181) but less so during subsequent feeding (ρ = 0.06, P = .6811). The median number of expelled sporozoites was of similar magnitude during the first and second feeding event, with a strong correlation between them (ρ = 0.56, P = .0002). We conclude that repeated feeding results in repeated sporozoite inoculation at similar intensity.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41774766 · DOI · PMC13271377
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Toxoplasma gondii: transmission, diagnosis and prevention [5]
- Research article Development of a metabolically active, non-replicating sporozoite vaccine to prevent Plasmodium falciparum malaria [6]
- Research article Rationale and plans for developing a non-replicating, metabolically active, radiation-attenuated Plasmodium falciparum sporozoite vaccine [7]
- Research article How to detect Toxoplasma gondii oocysts in environmental samples? [8]
- Research article Malarial proteases and host cell egress: an 'emerging' cascade [9]
- Research article Progress with Plasmodium falciparum sporozoite (PfSPZ)-based malaria vaccines [10]
References
- Swearingen KE, Lindner SE, Shi L, Shears MJ, Harupa A, Hopp CS, et al.. Interrogating the Plasmodium Sporozoite Surface: Identification of Surface-Exposed Proteins and Demonstration of Glycosylation on CSP and TRAP by Mass Spectrometry-Based Proteomics. . 2016. PMID 27128092 · DOI · PMC4851412
- Hopp CS, Chiou K, Ragheb DR, Salman AM, Khan SM, Liu AJ, et al.. Longitudinal analysis of Plasmodium sporozoite motility in the dermis reveals component of blood vessel recognition. . 2015. PMID 26271010 · DOI · PMC4594146
- Dong Y, Simões ML, Marois E, Dimopoulos G. CRISPR/Cas9 -mediated gene knockout of Anopheles gambiae FREP1 suppresses malaria parasite infection. . 2018. PMID 29518156 · DOI · PMC5843335
- Andolina C, van Gemert GJ, Ramjith J, Evers F, Graumans W, Stoter R, et al.. Expelling of Plasmodium falciparum Sporozoites by Anopheles stephensi Mosquitoes During Repeated Feeding. . 2026. PMID 41774766 · DOI · PMC13271377
- Hill D, Dubey JP. Toxoplasma gondii: transmission, diagnosis and prevention. Clin Microbiol Infect. 2002. PMID 12390281 · DOI
- Hoffman SL, Billingsley PF, James E, Richman A, Loyevsky M, Li T, et al.. Development of a metabolically active, non-replicating sporozoite vaccine to prevent Plasmodium falciparum malaria. Hum Vaccin. 2010. PMID 19946222 · DOI
- Luke TC, Hoffman SL. Rationale and plans for developing a non-replicating, metabolically active, radiation-attenuated Plasmodium falciparum sporozoite vaccine. J Exp Biol. 2003. PMID 14506215 · DOI
- Dumètre A, Dardé ML. How to detect Toxoplasma gondii oocysts in environmental samples?. FEMS Microbiol Rev. 2003. PMID 14638417 · DOI
- Blackman MJ. Malarial proteases and host cell egress: an 'emerging' cascade. Cell Microbiol. 2008. PMID 18503638 · DOI · PMC2610400
- Richie TL, Billingsley PF, Sim BK, James ER, Chakravarty S, Epstein JE, et al.. Progress with Plasmodium falciparum sporozoite (PfSPZ)-based malaria vaccines. Vaccine. 2015. PMID 26469720 · DOI · PMC5077156
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.