Impact of social media advertisements on the transmission dynamics of COVID-19 pandemic in India.

In this paper, we propose a mathematical model to assess the impact of social media advertisements in combating the coronavirus pandemic in India. We assume that dissemination of awareness among susceptible individuals modifies public attitudes and behaviours towards this contagious disease which results in reducing the chance of contact with the coronavirus and hence decreasing the disease transmission. Moreover, the individual's behavioral response in the presence of global information campaigns accelerate the rate of hospitalization of symptomatic individuals and also encourage the asymptomatic individuals for conducting health protocols, such as self-isolation, social distancing, etc. We calibrate the proposed model with the cumulative confirmed COVID-19 cases for the Republic of India. We estimate eight epidemiologically important parameters, and also the size of basic reproduction number for India. We find that the basic reproduction number for India is greater than unity, which represents the substantial outbreak of COVID-19 in the country. Sophisticated techniques of sensitivity analysis are employed to determine the impacts of model parameters on basic reproduction number and symptomatic infected population. Our results reveal that to reduce disease burden in India, non-pharmaceutical interventions strategies should be implemented effectively to decrease basic reproduction number below unity. Continuous propagation of awareness through the internet and social media platforms should be regularly circulated by the health authorities/government officials for hospitalization of symptomatic individuals and quarantine of asymptomatic individuals to control the prevalence of disease in India.

A Mathematical Model Supporting a Hyperpredation Effect in the Apparent Competition Between Invasive Eastern Cottontail and Native European Hare.

In this work a mathematical model is built in order to validate on theoretical grounds field study results on a three-species system made of two prey, of which one is native and another one invasive, together with a native predator. Specifically, our results mathematically describe the negative effect on the native European hare after the introduction of the invasive Eastern cottontail, mediated by an increased predation rate by foxes. Two nonexclusive assumptions can be made: an increase in cottontail abundance would lead to a larger fox population, magnifying their predatory impact ("hyperpredation") on hares; alternatively, cottontails attract foxes in patches where they live, which are also important resting sites for hares and consequently the increased presence of foxes results in a higher predation rates on hares. The model results support hyperpredation of increasing fox populations on native hares.

A Metaecoepidemic Model of Grassland Ecosystem with Only Consumers' Migration.

Metaecoepidemic models generalize metapopulation systems, combining local population dynamics with inter-patch migration coupled with an epidemic proliferation. A resource-consumer model is introduced with an ecosystem composed by two patches, in which consumers can freely move. A disease affects resources of the second patch. This situation corresponds to a grassland-herbivore environment, where one patch, managed in an extensive way, has a wider plant diversity, while the other one is highly fertilized leading to an important forage production. The latter is also subject to a fungal disease. Herbivores both feed on healthy or infected crop and can freely migrate between the two patches. A preliminary investigation focuses on behaviors emerging from some parts of the model, respectively, formed by uncoupled patches and by the purely demographic coupled model. Equilibria of the whole system are assessed and characterized. Results are then compared with the purely demographic model to highlight the role of the disease in this dynamics. A thorough numerical investigation of the model completes this analysis to assess the system behavior near each equilibrium. System bifurcations have also been explored as well as the response of the system equilibria to parameter perturbations. The disease eradication is possible under suitable circumstances. Coexistence of the five populations through persistent oscillations is also possible, but it is not at a stable level.

Modelling the Effect of Incubation and Latent Periods on the Dynamics of Vector-Borne Plant Viral Diseases.

Most of the plant viral diseases spread through vectors. In case of the persistently transmitted disease, there is a latent time of infection inside the vector after acquisition of the virus from the infected plant. Again, the plant after getting infectious agent shows an incubation time after the interaction with an infected vector before it becomes diseased. The goal of this work is to study the effect of both incubation delay and latent time on the dynamics of plant disease, and accordingly a delayed model has been proposed. The existence of the equilibria, basic reproductive number ([Formula: see text]) and stability of equilibria have been studied. This study shows the relevance of the presence of two time delays, which may lead to system stabilization.

Modeling the avoidance behavior of zooplankton on phytoplankton infected by free viruses.

In any ecosystem, chaotic situations may arise from equilibrium state for different reasons. To overcome these chaotic situations, sometimes the system itself exhibits some mechanisms of self-adaptability. In this paper, we explore an eco-epidemiological model consisting of three aquatic groups: phytoplankton, zooplankton, and marine free viruses. We assume that the phytoplankton population is infected by external free viruses and zooplankton get affected on consumption of infected phytoplankton; also, the infected phytoplankton do not compete for resources with the susceptible one. In addition, we model a mechanism by which zooplankton recognize and avoid infected phytoplankton, at least when susceptible phytoplankton are present. The zooplankton extinction chance increases on increasing the force of infection or decreasing the intensity of avoidance. Further, when the viral infection triggers chaotic dynamics, high zooplankton avoidance intensity can stabilize again the system. Interestingly, for high avoidance intensity, nutrient enrichment has a destabilizing effect on the system dynamics, which is in line with the paradox of enrichment. Global sensitivity analysis helps to identify the most significant parameters that reduce the infected phytoplankton in the system. Finally, we compare the dynamics of the system by allowing the infected phytoplankton also to share resources with the susceptible phytoplankton. A gradual increase of the virus replication factor turns the system dynamics from chaos to doubling state to limit cycle to stable state and the system finally settles down to the zooplankton-free equilibrium point. Moreover, on increasing the intensity of avoidance, the system shows a transcritical bifurcation from the zooplankton-free equilibrium to the coexistence steady state and remains stable thereafter.

An effective management strategy for the control of two lentiviruses in goat breedings.

Caprine Arthritis Encephalitis is an endemic disease in goat breedings, caused by viral strains belonging to the Small Ruminant Lentivirus group and characterized by a progressive chronic course. Its clinical signs are not immediately recognizable and can only be detected via costly serological tests. No vaccine is available. Two main strategies for fighting it are in common use. The "test-and-slaughter" approach, that selects infected goats and directly slaughters them, is expensive, time consuming and often leads to endemic low level persistence of the infection. Alternatively, newborns are removed from their mothers to be raised by healthy goats. After weaning they would rejoin their breeds, but then they could still be subject to horizontal contagion. In this study a mathematical model that considers the cocirculation of two different SRLV viral genotypes (B and E) is devised and analyzed, based on the key assumption of perfect cross-protection between the two genotypes' infections. Two strategic measures arise from its analysis, that are strongly recommended and whose implementation is encouraged: in the presence of both genotypes, the farmer should not isolate the newborns from their mothers but rather raise them with all the other animals. In the case of genotype-B-only affected farm, serological testing and mother-offspring separation should still be considered the best strategy for CAEV control. These strategies completely reverse the current removal policy and, in due conditions, would lead to disease eradication. These represent very reasonable and cheap measures for the eventual control of the epidemics.

Correction to: Diseased Social Predators.

In the original article, the second author's family name was misspelled. The correct name is Marta Paliaga.

Effects of Host Interspecific Interaction in the Maculinea-Myrmica Parasite-Host System.

A model of interspecific host competition in a system with one parasite (butterfly-Maculinea) and multiple potential hosts (ants-Myrmica) is presented. Results indicate that host interspecific competition increases the occurrence of multiple host behaviour in Maculinea natural populations but decreases the ability of the parasite populations to adapt to the most abundant host species. These qualitative predictions were compared with data on host specificity, with good agreement. Analysis of the data also indicates that Maculinea teleius and Maculinea arion respond differently to changes in relative host abundances. Maculinea teleius shows a larger fraction of sites where it displays multiple host behaviour and a larger fraction of sites where the niches of the hosts overlap. In some instances, Maculinea teleius is adapted to Myrmica hosts that are present in lower frequencies. Maculinea arion is locally more host-specific and occurs at sites where host interspecific competition is unlikely and is more frequently adapted to the most abundant host species.

Modeling the effects of variable feeding patterns of larval ticks on the transmission of Borrelia lusitaniae and Borrelia afzelii.

Spirochetes belonging to the Borrelia burgdoferi sensu lato (sl) group cause Lyme Borreliosis (LB), which is the most commonly reported vector-borne zoonosis in Europe. B. burgdorferi sl is maintained in nature in a complex cycle involving Ixodes ricinus ticks and several species of vertebrate hosts. The transmission dynamics of B. burgdorferi sl is complicated by the varying competence of animals for different genospecies of spirochetes that, in turn, vary in their capability of causing disease. In this study, a set of difference equations simplifying the complex interaction between vectors and their hosts (competent and not for Borrelia) is built to gain insights into conditions underlying the dominance of B. lusitaniae (transmitted by lizards to susceptible ticks) and the maintenance of B. afzelii (transmitted by wild rodents) observed in a study area in Tuscany, Italy. Findings, in agreement with field observations, highlight the existence of a threshold for the fraction of larvae feeding on rodents below which the persistence of B. afzelii is not possible. Furthermore, thresholds change as nonlinear functions of the expected number of nymph bites on mice, and the transmission and recovery probabilities. In conclusion, our model provided an insight into mechanisms underlying the relative frequency of different Borrelia genospecies, as observed in field studies.

Regime shifts and ecological catastrophes in a model of plankton-oxygen dynamics under the climate change.

It is estimated that more than a half of the total atmospheric oxygen is produced in the oceans due to the photosynthetic activity of phytoplankton. Any significant decrease in the net oxygen production by phytoplankton is therefore likely to result in the depletion of atmospheric oxygen and in a global mass mortality of animals and humans. In its turn, the rate of oxygen production is known to depend on water temperature and hence can be affected by the global warming. We address this problem theoretically by considering a model of a coupled plankton-oxygen dynamics where the rate of oxygen production slowly changes with time to account for the ocean warming. We show that, when the temperature rises sufficiently high, a regime shift happens: the sustainable oxygen production becomes impossible and the system's dynamics leads to fast oxygen depletion and plankton extinction. We also consider a scenario when, after a certain period of increase, the temperature is set on a new higher yet apparently safe value, i.e. before the oxygen depletion disaster happens. We show that in this case the system dynamics may exhibit a long-term quasi-sustainable dynamics that can still result in an ecological disaster (oxygen depletion and mass extinctions) but only after a considerable period of time. Finally, we discuss the early warning signals of the approaching regime shift resulting in the disaster.

Diseased Social Predators.

Social predators benefit from cooperation in the form of increased hunting success, but may be at higher risk of disease infection due to living in groups. Here, we use mathematical modeling to investigate the impact of disease transmission on the population dynamics benefits provided by group hunting. We consider a predator-prey model with foraging facilitation that can induce strong Allee effects in the predators. We extend this model by an infectious disease spreading horizontally and vertically in the predator population. The model is a system of three nonlinear differential equations. We analyze the equilibrium points and their stability as well as one- and two-parameter bifurcations. Our results show that weakly cooperating predators go unconditionally extinct for highly transmissible diseases. By contrast, if cooperation is strong enough, the social behavior mediates conditional predator persistence. The system is bistable, such that small predator populations are driven extinct by the disease or a lack of prey, and large predator populations survive because of their cooperation even though they would be doomed to extinction in the absence of group hunting. We identify a critical cooperation level that is needed to avoid the possibility of unconditional predator extinction. We also investigate how transmissibility and cooperation affect the stability of predator-prey dynamics. The introduction of parasites may be fatal for small populations of social predators that decline for other reasons. For invasive predators that cooperate strongly, biocontrol by releasing parasites alone may not be sufficient.

The role of algae in agriculture: a mathematical study.

Synthetic fertilizers and livestock manure are nowadays widely used in agriculture to improve crop yield but nitrogen and phosphorous runoff resulting from their use compromises water quality and contributes to eutrophication phenomena in waterbeds within the countryside and ultimately in the ocean. Alternatively, algae could play an important role in agriculture where they can be used as biofertilizers and soil stabilizers. To examine the possible reuse of the detritus generated by dead algae as fertilizer for crops, we develop three mathematical models building upon each other. A system is proposed in which algae recover waste nutrients (nitrogen and phosphorus) for reuse in agricultural production. The results of our study show that in so doing, the crop yield may be increased and simultaneously the density of algae in the lake may be reduced. This could be a way to mitigate and possibly solve the environmental and economic issues nowadays facing agriculture.

Modeling the impact of awareness on the mitigation of algal bloom in a lake.

The proliferation of algal bloom in water bodies due to the enhanced concentration of nutrient inflow is becoming a global issue. A prime reason behind this aquatic catastrophe is agricultural runoff, which carries a large amount of nutrients that make the lakes more fertile and cause algal blooms. The only solution to this problem is curtailing the nutrient loading through agricultural runoff. This could be achieved by raising awareness among farmers to minimize the use of fertilizers in their farms. In view of this, in this paper, we propose a mathematical model to study the effect of awareness among the farmers of the mitigation of algal bloom in a lake. The growth rate of awareness among the farmers is assumed to be proportional to the density of algae in the lake. It is further assumed that the presence of awareness among the farmers reduces the inflow rate of nutrients through agricultural runoff and helps to remove the detritus by cleaning the bottom of the lake. The results evoke that raising awareness among farmers may be a plausible factor for the mitigation of algal bloom in the lake. Numerical simulations identify the most critical parameters that influence the blooms and provide indications to possibly mitigate it.

[Cervical cancer screening with primary HPV-DNA test in the Local Health Authority 2 of Savona (Liguria Region, Northern Italy): a population-based study]. / Screening cervicovaginale con test HPV-DNA primario nella ASL 2 savonese: uno studio di popolazione.

OBJECTIVES: to describe the performance and the impact on the population coverage of a population-based organised screening programme with primary HPV-DNA test. DESIGN: population-based cohort study. SETTING AND PARTICIPANTS: organised screening programme for women aged 30-64 years. MAIN OUTCOME MEASURES: coverage of the target population with Pap test and HPV-DNA test, compliance to invitation, positivity at HPV-DNA testing, proportion of positive Pap test (squamous cells of undetermined significance or more severe, ASC-US+), referral for colposcopy, positive predictive value (PPV) of the cytology triage for grade-2 or more severe intraepithelial neoplasia (CIN2+), detection rate of CIN2+. Regarding coverage, seasonally adjusted trends of the PASSI surveillance from 2008 to 2014 were analysed. To evaluate performance, data of the information screening system were used. RESULTS: from December 2011 to December 2014, 48,852 women were invited for screening and 22,991 participated (48.4%); in addition, 968 women spontaneously participated in the programme, achieving a total of 23,959 screened women. The HPV test resulted positive for 2,000 women (8.4%). After triage 1,049 women were referred for colposcopy because of ASC-US+ (No. 968) or inadequate result (No. 81). The compliance at 12 months retesting among women with positive HPV test and negative triage was 79.3%, and the HPV positive rate was 60.4%. In the whole, 1,322 women were referred for colposcopy (5.5%) and 1,221 were actually tested. The overall detection rate for CIN2+ was 6.2/1,000. From 2011 to 2014, spontaneous Pap tests passed from 7,461/year to 2,491/year; the test coverage achieved a positive trend and it settles in recent years to 83%, including 43% of HPV-DNA. CONCLUSIONS: compliance to screening of invited women was satisfactory compared to previous experiences in Liguria Region (Northern Italy). Performance indicators confirm what was observed in other Italian experiences.

A model for voles interference in cultivated orchards.

We consider a dynamical system involving seven populations to model the presence of voles in a cultivated orchard. The plant population is stratified by age (three groups) and by health status (being damaged or not). The last equation models the voles with a modified logistic equation with Allee effect, where the modification takes into account the disturbance provided by the human activity on the orchard. Both an analytical investigation and numerical simulations on a case study are presented. The latter support the observed differences in the literature, in terms of number of voles, between cultivated and uncultivated fields.

A rare case of syncronous solitary para-pharyngeal metastasis of clear cell carcinoma in a patient with small renal mass.

INTRODUCTION: Unusual metastatic sites of renal cell carcinoma (RCC) are not infrequent. We report a rare case of solitary pharyngeal metastasis as first presentation of RCC. CASE DESCRIPTION: A 74 years-old man was referred to our hospital due to rapidly progressive dyspnoea and dysphagia. Physical examination showed a large right para-pharyngeal mass. Imaging findings showed a 5.5 cm mass, suspicious for malignancy, which extended to right para and retro-pharyngeal spaces with compression of the major right cervical vessels, C2-C3 vertebral bodies osteolysis, dural sac compression and dislocation. Futhermore, a small (2.6 × 2 cm) mass located at the upper pole of the right kidney was shown. Patient underwent partial trans-oral removal of the mass. Pathological examination and immunochemistry resulting strongly suggestive for metastatic RCC. Considering the metastatic stage of the tumour and the rapidly progressive clinical worsening with poor performance status, we offered the patient a palliative treatment with tyrosine kinase and cytoreductive radiotherapy on vertebral bodies. The patient developed a rapidly progressive multifocal metastatic disease and died 4 months after the presentation. CONCLUSION: We think that our case is noteworthy for some aspects. Firstly, pharyngeal localizations of RCC are very rare and this is the first case of solitary pharyngeal metastasis. Secondly, this metastatic lesion was really particular because it was synchronous and twice as big than the primary tumour. Thirdly, this case is consistent with previous evidence that synchronous compared with metachronous metastasis RCC is associated with adverse effect on outcome and response to targeted treatment.

The Consensus Project: Participation in cervical cancer screening by the first cohorts of girls offered HPV vaccination at age 15-16 years in Italy.

OBJECTIVE: To evaluate the association between human papillomavirus vaccination status and participation in cervical cancer screening (at age 25) by the first cohorts of girls who were offered vaccination at the age of 15 to 16 years in Italy. METHODS: Women born in 1993, 1994 and 1995 were invited to participate in cervical cancer screening between 2018 and 2020. We report participation in screening by vaccination status in three large areas, Florence province, Piedmont region and Savona province, where the Consensus Project was carried out. The relative risk of participation among vaccinated (≥2 doses) and unvaccinated women was estimated. Odds ratios (OR) of participation by vaccination status were estimated by logistic regression, adjusted by birthplace and birth cohort. RESULTS: Overall, 34,993 women were invited for screening: 13,006 (37.2%) participated and 10,062 of these agreed to participate in the Consensus intervention study. Among the invited women and screening participants, vaccinated women were 51.0% and 60.6%, respectively. Comparing vaccinated and unvaccinated women, the adjusted OR of screening participation was 1.80 (95% confidence interval (CI): 1.72-1.89), 2.17 (95% CI: 1.94-2.42), 1.59 (95% CI: 1.50-1.68) and 1.15 (95% CI: 0.86-1.54) for overall, Florence, Piedmont and Savona, respectively. About 33% of the invited women were unvaccinated and did not participate in screening: 25.8%, 59.5% and 64.2% of women born in Italy, in high migration pressure countries and in advanced development countries, respectively. CONCLUSIONS: Screening participation was higher among vaccinated than unvaccinated women. Active policies are needed to reduce inequalities, targeting the unscreened and unvaccinated population, particularly non-native women, to accelerate cervical cancer elimination in Italy.

An incubating diseased-predator ecoepidemic model.

We present a model for transmissible diseases spreading among predators in a predator-prey system. Upon successful contact, a susceptible individual becomes infected but is not yet able to spread the disease further. After an incubation period, the diseased individual becomes infectious. We investigate the system's equilibria by analytical and numerical means. For a suitable set of parameter values, the system shows persistent oscillations. The model also exhibits bistability of the coexistence equilibrium with the prey-only equilibrium.

Simple metaecoepidemic models.

We consider a simple predator-prey system with two possible habitats and where an epidemic spreads by contact among the prey, but it cannot affect the predators. Only the prey population can freely move from one environment to another. Several models are studied, for different assumptions on the structure of the demographic interactions and on the predators' feeding. Some counterintuitive results are derived. The role the safety refuge may in some cases entail negative consequences for the whole ecosystem. Also, depending on the system formulation, coexistence of all the populations may not always be supported.