Reproduction Number Research Articles

Optimal control for an SIR model with limited hospitalised patients

This paper analyses the optimal control of infectious disease propagation using a classic susceptible-infected-recovered (SIR) model characterised by permanent immunity and the absence of available vaccines. The control is performed over a time-dependent mean reproduction number, in order to minimise the cumulative number of ever-infected individuals (recovered), under different constraints. We consider constraints on non-pharmaceutical interventions ranging from partial lockdown to non-intervention, as well as the social and economic costs associated with such interventions, and the capacity limitations of intensive care units that limits the number of infected individuals to a maximum allowed value. We rigorously derive an optimal quarantine strategy based on necessary optimality conditions. The obtained optimal strategy is of a boundary-bang type, comprising three phases: an initial phase with no intervention, a second phase maintaining the infected population at its maximum possible value, and a final phase of partial lockdown applied over a single interval. The optimal policy is further refined by optimising the transition times between these phases. We show that these results are in excellent agreement with the numerical solution of the problem.

Estimating effective reproduction numbers using wastewater data from multiple sewersheds for SARS-CoV-2 in California counties

Estimating effective reproduction numbers using wastewater data from multiple sewersheds for SARS-CoV-2 in California counties

Impacts of legume and cereal based artificial diets on development and reproductive parameters of the armyworm Spodoptera litura (Lepidoptera: Noctuidae)

The development of a viable mass-production technique for the generalist herbivore Spodoptera litura Fabricius (Lepidoptera: Noctuidae), using various artificial diets, is crucial for conducting experiments to study its biology and propose control methods. This study aims to investigate the developmental biology of S. litura fed on three distinct diets: two legume-based diets (chickpea flour, Cicer arietinum L. and common bean flour, Phaseolus vulgaris L.) and a cereal-based diet (corn flour, Zea mays L.). Results on various developmental parameters and total life cycle durations indicated that the chickpea and bean-based diets yielded the superior outcomes, with shorter developmental periods (29.74 and 30.73 days, respectively) compared to the corn flour diet (33.10 days). Growth parameters derived from life tables, such as the net reproductive rate (Ro), intrinsic rate of increase (rm) and finite rate of increase (λ), were also higher on chickpea and bean-based diets than the corn flour diet. These results suggest that legumes such as chickpeas and beans, which are rich in vegetable proteins, fibers, carbohydrates and essential minerals, provide a higher-quality nutritional foundation for the growth of S. litura compared to corn-based diet. Furthermore, these diets are suitable for understanding the phenology of S. litura, especially in relation to the nutritional variations of its host plants.

Density-dependent fitness and mass-rearing of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) incorporating life table variability

The ectoparasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is an important natural enemy insect deployed for controlling lepidopteran larvae in warehouses and fields. However, there is limited information on mass-rearing methods of H. hebetor. This study investigated the effects of different Ephestia elutella (Hübner) (Lepidoptera: Pyralidae) and parasitic egg densities on the fitness and mass-rearing efficiency of H. hebetor, aiming to determine the optimal conditions for developing an economically viable and sustainable mass-rearing system for this parasitoid. Our results showed that the average number of eggs laid per host dropped below 7.54 eggs when the number of hosts exceeded five. H. hebetor exhibited significantly increased preadult survival rate (67.41%-81.00%), female and male body size (2224.55-2379.83 μm, 2213.39-2324.65 μm), fecundity (443.98-492.43 eggs), net reproductive rate (R0=154.57-216.67 offspring), intrinsic rate of increase (r=0.2776-0.3223 d-1), net paralyzed rate (C0=72.37-93.17 larvae), and net parasitism rate (Z0=43.55-55.04 larvae) at a density of 5-15 eggs per host than at 20 eggs per host. Meanwhile, considering rearing costs and production rate, a density of 5-15 eggs per host proved to be the most economical for mass-rearing H. hebetor, achieving a daily harvest rate of 10,000 newly emerged female adults. Therefore, for an efficient mass-rearing system for H. hebetor, maintaining a density of 5-15 eggs per host is recommended considering variability in life table and discarding aged individuals (after 36 days old). In summary, providing 5-10 5th instar larvae of E. elutella per day per pair of male and female parasitoid wasps is advised for effective mass-rearing of H. hebetor.

Epidemiological Implications of Vertical Transmission and Nonlinear Treatment in Lassa fever: A Mathematical Study

Lassa fever is a viral hemorrhagic disease primarily transmitted through contact with food or household items contaminated by urine or feces of infected rodents. The disease poses a significant health risk in endemic regions, yet the effect of vertical transmission and non-linear treatment on its spread has not been thoroughly explored. To address this, a mathematical model was constructed to assess the effect of vertical transmission and non-linear treatment in the transmission dynamics of Lassa fever. The model was validated through the theory of positivity and boundedness, ensuring that its solution remains biologically meaningful over time. The existence of equilibrium points was examined and the basic reproduction number was calculated using the next generation matrix operator. Bifurcation analysis is performed using the Center Manifold Theory. The Local and global stability of the model around the Lassa fever free equilibrium is investigated using Jacobian Matrix method and the theorem proposed by Castillo-Chavez. The effect of the parameters of the basic reproduction number was investigated using normalized forward sensitivity index. Furthermore, it was inferred that decrease in the contact rate and the rate of vertical transmission were instrumental to curtailing the spread of Lassa fever in the population.

Age–Stage, Two-Sex Life Table Analysis of Riptortus pedestris (Hemiptera: Alydidae) Across Different Soybean Varieties

Riptortus pedestris (Hemiptera: Alydidae) is an economically important pest of soybeans, significantly affecting their quality and market value. This study aims to evaluate the adaptability of R. pedestris to different soybean varieties and provide a foundation for selecting resistant varieties and developing effective integrated pest management strategies. Seven widely planted varieties (Beidou No. 3, Jiyu 47, Jiyu No. 80, Jiyu No. 90, Jiyu 203, Kangxianchong No. 6, and Kangxianchong 12) were selected for testing, and the developmental and population parameters of R. pedestris were measured using an age–stage, two-sex life table method. Notable differences were found in the developmental period, female longevity, and total preoviposition period (TPOP) of R. pedestris across diverse varieties. For those feeding on Kangxianchong 12, the nymph stage (14.73 ± 0.11 days), total longevity (37.35 ± 1.12 days), total female longevity (38.83 ± 1.80 days), and fecundity (38.86 ± 3.27 eggs per female) were all remarkably longer than on the other varieties. Additionally, the intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and average generation time (T) of R. pedestris varied significantly between soybean varieties. The lowest r (0.0789 ± 0.0075 per day) and λ (1.0821 ± 0.0081 per day) values were recorded for Kangxianchong No. 6, while the highest were for Jiyu 47 (r = 0.0933 ± 0.0070 per day, λ = 1.0978 ± 0.0076 per day). The R0 and T values for R. pedestris on Kangxianchong 12 (R0 = 16.33 ± 3.24 offspring per female, T = 31.18 ± 0.79 days) were remarkably higher than those of the other six varieties, suggesting that Kangxianchong 12 and Jiyu 47 are preferred hosts, whereas Kangxianchong No. 6 is less preferred. These results provide valuable insights for optimizing soybean cultivation and managing R. pedestris.

Effects of fine particulate matter air pollution on survival of Heliconius ethilla (Godart, 1819)

Human activities affect natural ecosystems worldwide and can generate negative effects on insect species such as growth inhibition, developmental abnormalities and reduction of reproductive and survival rates. Our study focused on fine particulate matter, a pollutant known to cause mechanical obstruction, heavy metal intoxication, and stress in Lepidoptera larvae. Heliconius ethilla (Lepidoptera: Nymphalidae) is a Heliconiinae found in the southeastern region of Brazil. We started our study with 3255 eggs, from which 69 stage 3 larvae were randomly separated as the treatment group. The larvae were fed with Passiflora edulis leaves and the SPM was added before being offered to the treatment group in an increasing concentration according to the age of the larvae and the leaf, simulating the gradual deposition of SPM in the environment. Our results demonstrate that Sedimentable Particulate Matter negatively impacted mortality rates, pupal weight, and body size. The results strongly indicate that the presence of SPM negatively impacts the survival, development and potentially the reproductive success of H. ethilla. A reduction in the population size and a consequent decrease in the chances of long-term survival of the species can be expected.

Dynamics of classical solutions of a multi-strain diffusive epidemic model with mass-action transmission mechanism.

We study a diffusive epidemic model and examine the spatial spreading dynamics of a multi-strain infectious disease. In particular, we address the questions of competitive-exclusion or coexistence of the disease's strains. Our results indicate that if one strain has its local reproduction function spatially homogeneous, which either strictly minimizes or maximizes the basic reproduction numbers, then the phenomenon of competitive-exclusion occurs. However, if all the local reproduction functions are spatially heterogeneous, several strains may coexist. In this case, we provide complete information on the large time behavior of classical solutions for the two-strain model when the diffusion rate is uniform within the population and the ratio of the local transmission rates is constant. Particularly, we prove the existence of two critical superimposed functions that serve as threshold values for the ratio of the transmission rates and that of the recovery rates. Furthermore, when the populations' diffusion rates are small, our result on the asymptotic profiles of coexistence endemic equilibria indicate a spatial segregation of infected populations.

Dynamic analysis of an HIV model with CTL immune response and logarithmic Ornstein–Uhlenbeck process

In this paper, we present a stochastic HIV model, including logistic growth, CTL immune response and logarithmic mean–reverting Ornstein–Uhlenbeck process. Firstly, we certify that there exists a unique global positive solution by rigorous mathematical analysis. Then, by constructing a suitable Lyapunov function and using the strong law of large numbers and Fatou’s lemma, we obtain the existence of the stationary distribution when stochastic reproduction number is greater than one. Moreover, we derive an approximate expression for the probability density function of the stochastic model around the infected equilibrium of its corresponding deterministic model. In addition, a critical condition for virus extinction is established. Finally, through numerical simulations, we investigate the effects of noise intensity and the logistic growth on model behavior, and we also explore the influence of key parameters on virus persistence and extinction.

Rapid spread of the SARS-CoV-2 Omicron XDR lineage derived from recombination between XBB and BA.2.86 subvariants circulating in Brazil in late 2023.

Recombination plays a crucial role in the evolution of SARS-CoV-2. The Omicron XBB* recombinant lineages are a noteworthy example, as they have been the dominant SARS-CoV-2 variant worldwide in the first half of 2023. Since November 2023, a new recombinant lineage between Omicron subvariants XBB and BA.2.86, designated XDR, has been detected mainly in Brazil. In this study, we reconstructed the spatiotemporal dynamics and estimated the absolute and relative transmissibility of the XDR lineage. The XDR lineage displayed a recombination breakpoint in the ORF1a-coding region, and the most closely related sequences to the 5' and 3' ends of the recombinant correspond to JD.1.1 and JN.1.1 lineages, respectively. The first XDR sequences were detected in November 2023 in the Northeastern Brazilian region, and their prevalence rapidly surged from <1% to 25% by February 2024. The Bayesian phylogeographic analysis supports that the XDR lineage likely emerged in the Northeastern Brazilian region around late October 2023 and rapidly disseminated within and outside Brazilian borders from mid-November onward. The median effective reproductive number of the XDR lineage in Brazil during the initial expansion phase was estimated to be around 1.5, and the average relative instantaneous reproduction numbers of XDR and JN* lineages were estimated to be 1.37 and 1.29 higher than that of co-circulating XBB* lineages. In summary, these findings support that the recombinant lineage XDR arose in the Northeastern Brazilian region in October 2023, shortly after the first detection of JN.1 sequences in the country. In Brazil, the XDR lineage exhibited a higher transmissibility level than its parental XBB.* lineages and is spreading at a rate similar to or slightly faster than the JN.1* lineages.IMPORTANCEThis study highlights the emergence and rapid dissemination of the recombinant SARS-CoV-2 XDR lineage, derived from the Omicron lineages JD.1.1 and JN.1.1. The XDR lineage exhibited equivalent transmissibility to its JN.1* parental lineages and quickly spread across Brazil in late 2023. The findings underscore the critical role of real-time genomic surveillance in detecting novel variants with higher transmission potential. By utilizing phylogenetic and epidemiological methods, this research provides important insights into the molecular dynamics of XDR, which could inform public health responses and vaccine composition updates. The study's significance lies in its ability to document the impact of recombination on viral evolution, offering valuable information to the field of virology and pandemic preparedness.

Impact of modified atmospheres enriched with carbon dioxide on the survival, biological, and physiological aspects of Aleuroglyphus ovatus (Troupeau, 1878)

Aleuroglyphus ovatus (Troupeau, 1878), a prevalent mite within stored products, inflicts substantial economic and health risks. The use of fumigants and grain protectants as methods of stored grain pest management had resulted in resistance and environmental concerns, necessitating alternative strategies. This study explored the toxicity of modified atmospheres composed of CO2, as an environmentally friendly, residue-free, and viable disinfestation alternative. The mortality of A. ovatus increased significantly with an increase in either CO2 concentration or exposure duration. Complete adult mortality was recorded after 72 h of treatment with 95% CO2. The calculated LT50 value was 30.52 h under 35% CO2, and it decreased to 11.78 h under 95% CO2. Additionally, CO2 exposure led to changes in the activity of antioxidant and detoxification enzymes in A. ovatus, indicating its physiological adaptation mechanisms under varying CO2 concentrations and the impact of these changes on development and reproductive capacity. Enzymatic assays revealed a concentration-dependent decrease in superoxide dismutase activity and an increase in catalase activity. The detoxification enzymes, glutathione S-transferase, and carboxylesterase demonstrated adaptive upregulation. The development of A. ovatus was delayed, and its reproductive capacity was reduced under CO2 stress. Population parameters, including the net reproductive rate (R0) and intrinsic rate of increase (rm) were all significantly reduced under CO2 stress, with 35% CO2 showing the severer impact. The study concludes that CO2 can be an effective tool for pest management in stored products, with 35% CO2 showing potential as a more economical option for A. ovatus extermination.

Quantifying ivermectin's optimal strategy impacts on malaria transmission: a dual-structured mathematical model

Ivermectin (IVM), used alongside mass treatment strategies, has been suggested as a potential tool for reducing malaria transmission. The effectiveness of IVM in shortening vector lifespan depends on the time elapsed between the administration of IVM to the host and the blood meal taken by the vector. This effectiveness is measured by the median effective dose ( ED 50 ), the IVM concentration required to kill 50% of mosquitoes after a specific host exposure period. We use a mathematical model structured by human and vector exposure times to IVM and the model's well-posedness is established through semigroups theory. We calculate the basic reproduction number, linking it to epidemiological dynamics, and show steady states bifurcate at R 0 = 1 , governed by a constant C bif . We identify the optimal human exposure to IVM and intervention interval to reduce prevalence by 10% to 20%. This depends on the IVM formulation ( ED 50 ) and the target number of campaigns in the host population.

Analysis of tuberculosis model with indirect environmental transmission and optimal control.

In this paper, the dynamic behaviors of tuberculosis in the context of indirect environmental transmission are discussed by establishing the SEIRB epidemic model. The basic reproduction number is computed by employing the next-generation matrix approach. The global stability of disease-free equilibrium and endemic equilibrium is proved by constructing the Lyapunov function and the application of LaSalle's invariance principle. It shows that when the basic reproduction number is greater than 1, tuberculosis will spread among the population. When the basic reproduction number is less than 1, tuberculosis will disappear. Finally, an optimal control problem is constructed by using the extended model, which reveals the spread of tuberculosis can be effectively controlled by eliminating Mycobacterium tuberculosis in the environment and controlling tuberculosis patients at the same time. Numerical example results show the effectiveness of the optimization strategies.

Use of the WHO partograph and Zhang’s guideline for labor and delivery in China: implications for clinical practice

BackgroundThere is an unmet need for a large comprehensive population-based dataset documenting national birthing trends in China and a partograph specifically tailored to Chinese women. This study assessed the impact of using the World Health Organization (WHO) partograph or Zhang’s guideline to manage labor and delivery in China and inform the development of a partograph that specifically aligns with the progression of labor in Chinese women.MethodsThis retrospective analysis included low-risk nulliparous women with a singleton, full-term fetus in cephalic presentation entering spontaneous labor at a specialized obstetric hospital in China between January 2010 and June 2022. Pregnant women were managed according to the WHO partograph (January 2010-August 2014, n = 31,286) or Zhang’s guideline (September 2014-June 2022, n = 49,821).ResultsRates of assisted reproduction (4.57% vs. 1.05%; p < 0.0001) and hypertension (7.44% vs. 6.71%; p < 0.0001) were significantly higher for pregnant women managed according to Zhang’s guideline compared to the WHO partograph. Rates of labor intervention (35.31% vs. 13.95%; p < 0.0001), including induction of labor by oxytocin, artificial rupture of membranes, lateral episiotomy and conversion to cesarean section (all, p < 0.0001), were significantly higher for pregnant women managed according to the WHO partograph. Rates of forceps assisted vaginal deliveries (12.67% vs. 6.42%; p < 0.0001) and postpartum hemorrhage (10.9% vs. 6.2%; p < 0.0001) were significantly higher, and birth asphyxia (0.15% vs. 0.09%; p = 0.02) was significantly lower, for pregnant women managed according to Zhang’s guideline.ConclusionsThis study provides valuable insights into the utilization of the WHO partograph and Zhang’s guideline in managing labor and delivery among Chinese women. Findings indicate that women managed according to Zhang’s guideline had higher rates of assisted reproduction and hypertension, suggesting a potentially different demographic profile or underlying health conditions compared to women managed according to the WHO partograph. Notably, the use of the WHO partograph was linked to a significant increase in labor interventions, while Zhang’s guideline resulted in higher rates of forceps-assisted vaginal deliveries and postpartum hemorrhage, yet interestingly, a lower incidence of birth asphyxia. These contrasting outcomes underscore the importance of aligning labor management tools with the specific needs and progression of labor in Chinese women. The results advocate for a tailored partograph that could better reflect the unique characteristics of Chinese women and optimize decision making and maternal and neonatal outcomes.

Modeling optimal control strategies for HIV and gonorrhea co-infection: incorporating screening along with treatment

Abstract Human immunodeficiency virus (HIV) and gonorrhea are significant infectious diseases that pose considerable public health challenges worldwide. In this study, a control-induced model is developed to explore the dynamics of HIV and gonorrhea co-infection in the presence of treatment, incorporating screening strategies as control variables. We establish qualitative behavior, such as nonnegativity and boundedness of the solutions, and compute the basic reproduction number by utilizing the next generation matrix method. Subsequently, the stability of the disease-free equilibrium is analyzed, and then sensitivity analysis is undertaken to pinpoint the most critical parameters. Furthermore, an optimal control problem is formulated to diminish the total count of infected individuals and associated costs. The existence of an optimal control is shown, and Pontryagin’s principle is employed to derive the necessary conditions for an optimality system. Additionally, numerical simulations reveal that without control measures, the model predicts a continual rise in the number of infections. However, the graphical results demonstrate that the simultaneous implementation of screening for both HIV and gonorrhea as control measures significantly reduces single infections as well as co-infections. These insights are vital for researchers and policymakers to develop effective intervention strategies for eradicating co-infections of HIV and gonorrhea.

Transmissibility and control of tuberculosis in school outbreaks: a modeling study based on four outbreaks in China

BackgroundThe elevated incidence of tuberculosis (TB) outbreaks in schools poses a significant challenge to prevention and control efforts in China. The commonality among most outbreaks is the failure to isolate patients at an early stage. Early isolation of TB cases is crucial for reducing the spread of TB within schools. This study aims to quantify the impact of different isolation proportions and durations on the attack rate of TB in schools. It explored the intervention effects of isolation measures in preventing and controlling TB in school settings. The goal is to provide insights that can serve as a reference for reducing the occurrence of TB outbreaks in schools.MethodsWe collected data from 4 school TB outbreaks. Susceptible-Exposed-Infected-Recovered (SEIR) model was used to fit the collected data and calculate transmissibility. Susceptible-Exposed-Infected-Quarantined-Recovered (SEIQR) model was employed to evaluate the effect of isolation. Effective reproduction numbers and cumulative incidence were used to quantify the transmissibility of TB.ResultsIn the 4 outbreaks, the majority of student cases were distributed in high grades of high school and universities, with a widespread occurrence of significant intervention delays. The median ascending reproduction value for the 4 outbreaks was 18.44 [interquartile range: 15.40-20.11]. Isolating 100% of the patients at the first month could reduce the number of cases by 99.47%, 87.99%, 96.48%, and 99.16%, respectively.ConclusionsThis study suggests that high schools and universities may represent significant high-risk environments for TB outbreaks. Early detection and isolation of cases are important strategies that can help reduce the risk of TB outbreaks, with observed case reductions of up to 99.47% when implemented promptly.

Risk‐Taking in Bluebirds After Exposure to a Nest Predator Relates to Parental Roles and Shows Little Cooperation Between Partners

ABSTRACTParents may experience a trade‐off between caring for offspring and protecting themselves from predators. The reproductive value hypothesis predicts that parents should take more risks for older, more valuable offspring, whereas the harm to offspring hypothesis predicts that parents should risk more for vulnerable offspring that would suffer most from a lack of parental care at the moment. After exposing parent mountain bluebirds (Sialia, currucoides) to a model predator, we recorded latency times for them to touch, to look into, and to enter their nestbox and the number of times they inspected the box across three breeding stages: nest‐building, incubation and nestling‐rearing. Females took greater risks than males during the nest‐building and incubation stages by inspecting and entering boxes sooner and more times, consistent with their role in parental care at those early breeding stages that requires them to enter the box. Risk‐taking in males was consistent with the reproductive value hypothesis, increasing across breeding stages. In contrast, females took the greatest risk during incubation, consistent with the harm to offspring hypothesis. Furthermore, the riskiest behaviours were not correlated between pair members, and both sexes assumed the risk to first inspect the nestbox approximately equally. This suggests there is not a ‘war of attrition’ between mates over risk‐taking, but neither was there cooperation by the male to facilitate the rapid resumption of parental care by his mate. The results highlight that patterns of investment in nest defense in birds may be sex‐specific.

Regional variation in demographics, reproduction, and body mass growth rates of wild pigs: Implications for population control

AbstractWild pigs are a destructive invasive species throughout many regions of the world and have proven difficult to control or eliminate. Their success as an invasive species is, in part, from their high reproductive potential, which can vary based on available resources, ancestry, and other factors. We opportunistically collected data on demographics (i.e., age and sex), reproduction, and body mass on 2,762 wild pigs throughout various research and operation control activities in Texas, Alabama, Hawai'i, Guam (USA), and Queensland (Australia) during 2016–2024. We evaluated these data for differences among study sites that might lead to a better understanding of wild pig ecology and more effective control of their populations. We found that the age structures of wild pigs varied greatly among sites, with areas with more intense control having younger populations. The timing and frequency of birth pulses also varied by site. Large disparities among populations demonstrated the elasticities of wild pigs in invaded ranges; for example, the Alabama study site had a mostly young population with fast body mass growth rates and 2 discernable birth pulses per year, whereas the Guam study site had an older population with slow body mass growth rates and an indistinguishable birth pulse. We hypothesized that intense population control may increase reproduction rates in younger females through increased body mass growth rates and subsequent reproductive maturity. We recommend that managers identify the seasonal birth pulses of wild pigs in their region, and then intensively focus on removing wild pigs during the 115 days (i.e., gestation period) prior to those birth pulses. This may be counterintuitive to managers that focus on trapping after observing a birth pulse, but it increases the probability of simultaneously removing pregnant females and any associated offspring from previous litters that remained with the pregnant female. We also recommend evaluating regional‐specific intensities of removal that might be required for reducing populations with specific emphasis on whether compensatory reproductive behaviors are generated and how to avoid them.

Dynamic Analysis of Rumor Spreading Model Based on Three Recovery Modes

In this paper, an SIR rumor propagation model is established with the three recovery modes that the spreader turns into a stifler under the influence of the spreader, stifler and media nonlinear rumor-refuting mechanism. Firstly, we calculate the basic regeneration number, and we determine the stability of the rumor-free equilibrium and the existence of the rumor-endemic equilibrium. Secondly, by applying the strict symbolic calculation methods of singular quantities, we investigate the Hopf bifurcation at the rumor-endemic equilibrium, and we determine the existence of single and double periodic solutions under certain parameter conditions. Thirdly, we discuss the practical dynamic behaviors of rumors spreading from the perspectives of the basic reproduction number and periodic solutions, especially the correlation between these two and multi-periodic oscillations. To our knowledge, such complex dynamic properties have rarely been analyzed in rumor models.

The usefulness of C. elegans life span analysis in screening for functional foods.

Caenorhabditis elegans is a type of nematode that has significantly contributed to aging research as a multicellular animal model because of its high reproductive rate, ease of cultivation, low cost, short generation cycle, body transparency, and eukaryotic nature. Since the discovery of long-lived mutant strains of C. elegans, signaling pathways involved in lifespan have been elucidated. Some of these pathways are shared with mammals, indicating that aging research in C. elegans may be applied to other animals, including humans. Studies on the mechanisms of aging have advanced with the availability of mutants for these pathways. In recent years, C. elegans has also contributed to the discovery of antioxidants and the elucidation of the molecular mechanisms responsible for the anti-aging effects of foods and traditional medicines with lifespan as an indicator. This review summarizes the characteristics of C. elegans for life span analysis associated with functional foods.