Infectious diseases can seriously impact dynamics of their host species. In this study, we model and analyze an interaction between a sexually transmitted infection and its animal host population affected by a mate-finding Allee effect. Since mating drives both host reproduction and infection transmission, the Allee effect shapes the transmission rate of the infection which we show takes a saturating form. Our model combining sexually transmitted infections with the mate-finding Allee effect in the host produces quite rich dynamics, including oscillations, several multistability regimes, and infection-induced host extinction. However, many of these complex patterns are restricted to a relatively narrow parameter range. We find that the host extinction occurs at intermediate levels of infection virulence, as well as for Allee effect strengths much lower than when the infection is absent. In both cases, a sequence of events comprising destabilization of an endemic equilibrium, growth of oscillation amplitude, and a heteroclinic bifurcation forms an underlying mechanism. We apply our model to the feline immunodeficiency virus (FIV) in domestic cats.

• Klíčová slova
• Allee effect, Asymptotic incidence, Bifurcation, Mating, Reproduction–transmission consistency, Sexually transmitted disease,
• MeSH
• biologické modely * MeSH
• hustota populace MeSH
• infekční nemoci MeSH
• interakce hostitele a patogenu * MeSH
• kočičí AIDS přenos   virologie   MeSH
• kočky MeSH
• populační dynamika MeSH
• populační růst MeSH
• sexuálně přenosné nemoci MeSH
• virus kočičí imunodeficience * MeSH
• zvířata MeSH
• Check Tag
• kočky MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Sexually transmitted infections are ubiquitous in nature and affect many populations. The key process for their transmission is mating, usually preceded by mate choice. Susceptible individuals may avoid mating with infected individuals to prevent infection provided it is recognizable. We show that accounting for infection avoidance significantly alters host population dynamics. We observe bistability between the disease-free and endemic or disease-induced extinction equilibria, significant abrupt reduction in the host population size and disease-induced host extinction. From the population persistence perspective, the best strategy is either not to avoid mating with the infected individuals, to prevent disease-induced host extinction, or to completely avoid mating with the infected individuals, to prevent pathogen invasion. Increasing sterilization efficiency of the infection leads to lower population sizes and reduced effect of mating avoidance. We also find that the disease-free state is more often attained by populations with strong polyandry, whereas a high-density endemic state is more often observed for populations with strong polygyny, suggesting that polygamy rather than monogamy may be promoted in denser host populations.

• Klíčová slova
• Mate choice, Mating preferences, Mating system, Reproduction-transmission consistency, Sterilization,
• MeSH
• biologické modely * MeSH
• hustota populace * MeSH
• lidé MeSH
• populační dynamika * MeSH
• sexuálně přenosné nemoci * epidemiologie   přenos   MeSH
• sexuální chování zvířat * MeSH
• sexuální chování * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Models of sexually transmitted infections have become a fixture of mathematical epidemiology. A common attribute of all these models is treating reproduction and mating, and hence pathogen transmission, as uncoupled events. This is fine for humans, for example, where only a tiny fraction of sexual intercourses ends up with having a baby. But it can be a deficiency for animals in which mating and giving birth are tightly coupled, and mating thus mediates both reproduction and pathogen transmission. Here, we model dynamics of sterilizing, sexually transmitted infections in such animals, assuming structural consistency between the processes of reproduction and pathogen transmission. We show that highly sterilizing, sexually transmitted pathogens trigger bistability in the host population. In particular, the host population can end up in two extreme alternative states, disease-free persistence and pathogen-driven extinction, depending on its initial state. Given that sterilizing, sexually transmitted infections that affect animals are abundant, our results might implicate an effective pest control tactic that consists of releasing the corresponding pathogens, possibly after genetically enhancing their sterilization power.

• MeSH
• biologické modely * MeSH
• infertilita mikrobiologie   veterinární   MeSH
• populační dynamika MeSH
• sexuálně přenosné nemoci mikrobiologie   prevence a kontrola   veterinární   MeSH
• sexuální chování zvířat * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Although seasonal variation has a known influence on the transmission of several respiratory viral infections, its role in SARS-CoV-2 transmission remains unclear. While there is a sizable and growing literature on environmental drivers of COVID-19 transmission, recent reviews have highlighted conflicting and inconclusive findings. This indeterminacy partly owes to the fact that seasonal variation relates to viral transmission by a complicated web of causal pathways, including many interacting biological and behavioural factors. Since analyses of specific factors cannot determine the aggregate strength of seasonal forcing, we sidestep the challenge of disentangling various possible causal paths in favor of a holistic approach. We model seasonality as a sinusoidal variation in transmission and infer a single Bayesian estimate of the overall seasonal effect. By extending two state-of-the-art models of non-pharmaceutical intervention (NPI) effects and their datasets covering 143 regions in temperate Europe, we are able to adjust our estimates for the role of both NPIs and mobility patterns in reducing transmission. We find strong seasonal patterns, consistent with a reduction in the time-varying reproduction number R(t) (the expected number of new infections generated by an infectious individual at time t) of 42.1% (95% CI: 24.7%-53.4%) from the peak of winter to the peak of summer. These results imply that the seasonality of SARS-CoV-2 transmission is comparable in magnitude to the most effective individual NPIs but less than the combined effect of multiple interventions.

• MeSH
• Bayesova věta MeSH
• COVID-19 * epidemiologie   MeSH
• lidé MeSH
• podnebí MeSH
• roční období MeSH
• SARS-CoV-2 * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The practicality of administrative measures for covid-19 prevention is crucially based on quantitative information on impacts of various covid-19 transmission influencing elements, including social distancing, contact tracing, medical facilities, vaccine inoculation, etc. A scientific approach of obtaining such quantitative information is based on epidemic models of S I R family. The fundamental S I R model consists of S-susceptible, I-infected, and R-recovered from infected compartmental populations. To obtain the desired quantitative information, these compartmental populations are estimated for varying metaphoric parametric values of various transmission influencing elements, as mentioned above. This paper introduces a new model, named S E I R R P V model, which, in addition to the S and I populations, consists of the E-exposed, R e -recovered from exposed, R-recovered from infected, P-passed away, and V-vaccinated populations. Availing of this additional information, the proposed S E I R R P V model helps in further strengthening the practicality of the administrative measures. The proposed S E I R R P V model is nonlinear and stochastic, requiring a nonlinear estimator to obtain the compartmental populations. This paper uses cubature Kalman filter (CKF) for the nonlinear estimation, which is known for providing an appreciably good accuracy at a fairly small computational demand. The proposed S E I R R P V model, for the first time, stochastically considers the exposed, infected, and vaccinated populations in a single model. The paper also analyzes the non-negativity, epidemic equilibrium, uniqueness, boundary condition, reproduction rate, sensitivity, and local and global stability in disease-free and endemic conditions for the proposed S E I R R P V model. Finally, the performance of the proposed S E I R R P V model is validated for real-data of covid-19 outbreak.

• Klíčová slova
• Compartment-based epidemic model, Cubature rule, Kalman filter,
• Publikační typ
• časopisecké články MeSH

Studying biology of sperm provides valuable information to optimize artificial reproduction and is crucial for sustainable aquaculture. Here, we investigated morphology of spermatozoon in Atlantic cod (Gadus morhua) using transmission and scanning electron microscopy. Furthermore, spermatozoa motility kinetics at different osmolalities were studied using computer-assisted sperm analysis software. The spermatozoon lacked an acrosome and consisted of a head, midpiece, and flagellum. The head of spermatozoa was round, oval, and rather elongated in shape, showing high variations in dimensions. There were up to 6 mitochondria that encircled the proximal part of the flagellum. The proximal and distal centrioles were located within the nuclear notch and arranged orthogonal to each other. The axoneme had a typical 9 + 2 microtubule structure. The flagellar length of spermatozoon was 66.94 ± 0.46 μm. Spermatozoa were immotile in the seminal plasma. Dilution of sperm with natural seawater (1100 mOsmol/kg) resulted in initiation of motility for 91.0 ± 3.4% of spermatozoa with average velocity of 86.2 ± 2.3 μm/s and beating frequency of 52 Hz. The duration of spermatozoa motility was > 6 min; however, the percentage of motile spermatozoa decreased at 60 s post-activation. When osmolality of natural seawater was modified using distilled water or NaCl, spermatozoa motility was not initiated at ≤ 400 and ≥ 2500 mOsmol/kg, and the highest percentage of motility was observed at 730-1580 mOsmol/kg. In a sucrose solution, spermatozoa motility was initiated and suppressed at 600 and 1500 mOsmol/kg, respectively, and highest percentage of motility was observed at 800-1100 mOsmol/kg. Spermatozoon morphology comparisons within Gadiformes showed differences in dimensions of head and mitochondria, flagellar length, and number of mitochondria. The present study provides valuable data that can be used for phylogenetic implications based on spermatozoon morphology and for development of artificial fertilization and sperm cryopreservation protocols based on sperm motility.

• Klíčová slova
• Beat frequency, Electron microscopy, Ions, Osmolality, Sperm ultrastructure, Sperm velocity,
• MeSH
• Gadus morhua fyziologie   MeSH
• motilita spermií fyziologie   MeSH
• osmolární koncentrace MeSH
• spermie fyziologie   ultrastruktura   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Ukraine has the highest rate of HIV infection in Europe, with an estimated adult prevalence of 1.6 percent. The epidemic in Ukraine remains largely driven by injection drug use, and women of reproductive age are being increasingly affected. Prior research has highlighted the need to improve the quality of services for prevention of mother-to-child transmission (PMTCT) and to address other issues related to HIV counseling, testing, and care, especially in the context of antenatal and obstetric services. METHODS: From 2004 to 2007, PATH led a collaborative effort to improve the quality of PMTCT services in Ukraine. Initial assessments included focus groups with Ukrainian women and review of existing educational materials. Interventions focused on training providers to improve skills in communication and referral to community-based support; they also addressed the underlying issue of stigma. RESULTS: Observational data demonstrated that providers who participated in the training intervention delivered PMTCT counseling of a consistently higher quality than did providers who did not undergo training. Exit interviews with clients confirmed these findings. CONCLUSIONS: An intervention focused on strengthening voluntary counseling and testing for HIV, forging partnerships with local organizations, and undoing HIV-related stigma can help to improve access to and quality of PMTCT services in antenatal care clinics.

• MeSH
• HIV infekce diagnóza   prevence a kontrola   přenos   MeSH
• infekční komplikace v těhotenství prevence a kontrola   virologie   MeSH
• lidé MeSH
• pacientův souhlas se zdravotní péčí MeSH
• pilotní projekty MeSH
• poradenství MeSH
• služby zdravotní péče o matku organizace a řízení   normy   MeSH
• svépomocné skupiny * MeSH
• těhotenství MeSH
• vertikální přenos infekce prevence a kontrola   MeSH
• vyrovnaná skupina MeSH
• vzdělávání pacientů jako téma MeSH
• zdravotní pomocníci v komunitě výchova   MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Ukrajina MeSH

STUDY QUESTION: Can oocyte functionality be assessed by observing changes in their intracytoplasmic lipid droplets (LDs) profiles? SUMMARY ANSWER: Lipid profile changes can reliably be detected in human oocytes; lipid changes are linked with maternal age and impaired developmental competence in a mouse model. WHAT IS KNOWN ALREADY: In all cellular components, lipid damage is the earliest manifestation of oxidative stress (OS), which leads to a cascade of negative consequences for organelles and DNA. Lipid damage is marked by the accumulation of LDs. We hypothesized that impaired oocyte functionality resulting from aging and associated OS could be assessed by changes in LDs profile, hereafter called lipid fingerprint (LF). STUDY DESIGN, SIZE, DURATION: To investigate if it is possible to detect differences in oocyte LF, we subjected human GV-stage oocytes to spectroscopic examinations. For this, a total of 48 oocytes derived from 26 young healthy women (under 33 years of age) with no history of infertility, enrolled in an oocyte donation program, were analyzed. Furthermore, 30 GV human oocytes from 12 women were analyzed by transmission electron microscopy (TEM). To evaluate the effect of oocytes' lipid profile changes on embryo development, a total of 52 C57BL/6 wild-type mice and 125 Gnpat+/- mice were also used. PARTICIPANTS/MATERIALS, SETTING, METHODS: Human oocytes were assessed by label-free cell imaging via coherent anti-Stokes Raman spectroscopy (CARS). Further confirmation of LF changes was conducted using spontaneous Raman followed by Fourier transform infrared (FTIR) spectroscopies and TEM. Additionally, to evaluate whether LF changes are associated with developmental competence, mouse oocytes and blastocysts were evaluated using TEM and the lipid dyes BODIPY and Nile Red. Mouse embryonic exosomes were evaluated using flow cytometry, FTIR and FT-Raman spectroscopies. MAIN RESULTS AND THE ROLE OF CHANCE: Here we demonstrated progressive changes in the LF of oocytes associated with the woman's age consisting of increased LDs size, area, and number. LF variations in oocytes were detectable also within individual donors. This finding makes LF assessment a promising tool to grade oocytes of the same patient, based on their quality. We next demonstrated age-associated changes in oocytes reflected by lipid peroxidation and composition changes; the accumulation of carotenoids; and alterations of structural properties of lipid bilayers. Finally, using a mouse model, we showed that LF changes in oocytes are negatively associated with the secretion of embryonic exosomes prior to implantation. Deficient exosome secretion disrupts communication between the embryo and the uterus and thus may explain recurrent implantation failures in advanced-age patients. LIMITATIONS, REASONS FOR CAUTION: Due to differences in lipid content between different species' oocytes, the developmental impact of lipid oxidation and consequent LF changes may differ across mammalian oocytes. WIDER IMPLICATIONS OF THE FINDINGS: Our findings open the possibility to develop an innovative tool for oocyte assessment and highlight likely functional connections between oocyte LDs and embryonic exosome secretion. By recognizing the role of oocyte LF in shaping the embryo's ability to implant, our original work points to future directions of research relevant to developmental biology and reproductive medicine. STUDY FUNDING/COMPETING INTEREST(S): This research was funded by National Science Centre of Poland, Grants: 2021/41/B/NZ3/03507 and 2019/35/B/NZ4/03547 (to G.E.P.); 2022/44/C/NZ4/00076 (to M.F.H.) and 2019/35/N/NZ3/03213 (to Ł.G.). M.F.H. is a National Agency for Academic Exchange (NAWA) fellow (GA ULM/2019/1/00097/U/00001). K.F. is a Diamond Grant fellow (Ministry of Education and Science GA 0175/DIA/2019/28). The open-access publication of this article was funded by the Priority Research Area BioS under the program "Excellence Initiative - Research University" at the Jagiellonian University in Krakow. The authors declare no competing interest. TRIAL REGISTRATION NUMBER: N/A.

• Klíčová slova
• Gnpat, carotenoids, coherent anti-Stokes Raman spectroscopy, exosomes, lipid analysis, lipid droplets, oocyte,
• MeSH
• dospělí MeSH
• embryonální vývoj fyziologie   MeSH
• lidé MeSH
• lipidová tělíska metabolismus   MeSH
• metabolismus lipidů MeSH
• myši inbrední C57BL * MeSH
• myši MeSH
• oocyty * metabolismus   MeSH
• oxidační stres MeSH
• Ramanova spektroskopie MeSH
• stárnutí metabolismus   MeSH
• transmisní elektronová mikroskopie MeSH
• věk matky MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH