Factors affecting the levels of protection transferred from mother to offspring following immune challenge

Number of tetanus toxoid injections before birth and associated factors among pregnant women in low and middle income countries: Negative binomial poisson regression

BACKGROUND

In low- and middle-income countries where vaccination rates are low, tetanus is still an important threat to public health. Although maternal and neonatal tetanus remains a major global health concern, its magnitude and determinates are not well studied. Therefore, this study aimed to assess the number of tetanus toxoid injections and associated factors among pregnant women in low- and middle-income countries.

METHODS

Data from the most recent Demographic and Health Surveys, which covered 60 low- and middle-income countries from 2010 to 2022, was used for secondary data analysis. The study included a total of 118,704 pregnant women. A statistical software package, STATA 14, was used to analyze the data. A negative binomial regression of a cross-sectional study was carried out. Factors associated with the number of tetanus vaccinations were declared significant at a p-value of < 0.05. The incidence rate ratio and confidence interval were used to interpret the results. A model with the smallest Akaike Information Criterion and Bayesian Information Criterion values and the highest log likelihood was considered the best-fit model for this study.

RESULTS

In low- and middle-income countries, 26.0% of pregnant women took at least two doses of the tetanus toxoid vaccine. Factors such as maternal education, primary (IRR = 1.22, 95% CI: 1.17, 1.26), secondary (IRR = 1.19, 95% CI: 1.15, 1.23), higher (IRR = 1.16, 95% CI: 1.12, 1.20), employment (IRR = 1.11, 95% CI: 1.09, 1.13), 1-3 ANC visits (IRR = 2.49, 95% CI: 2.41, 2.57), ≥4 visits (IRR = 2.94, 95% CI: 2.84, 3.03), wealth index (IRR = 1.06; 95% CI: 11.04, 1.08), ≥birth order (IRR = 1.04, 95% CI: 1.02, 1.27), distance to health facility (IRR = 1.02, 95% CI: 1.00, 1.03), and health insurance coverage (IRR = 1.08; 95% CI: 1.06, 1.10) had a significant association with the number of tetanus vaccinations among pregnant women.

CONCLUSIONS AND RECOMMENDATIONS

This study concludes that the number of tetanus toxoid vaccinations among pregnant women in low- and middle-income countries is low. In the negative binomial model, the frequency of tetanus vaccinations has a significant association with maternal employment, educational status, wealth index, antenatal care visits, birth order, distance from a health facility, and health insurance. Therefore, the ministries of health in low and middle-income countries should give attention to those women who had no antenatal care visits and women from poor wealth quantiles while designing policies and strategies.

Egg viability and egg mass underlie immune tradeoffs and differences between urban and rural lizard egg yolk physiology

Urbanization can cause innumerable abiotic and biotic changes that have the potential to influence the ecology, behavior, and physiology of native resident organisms. Relative to their rural conspecifics, urban Side-blotched Lizard (Uta stansburiana) populations in southern Utah have lower survival prospects and maximize reproductive investment via producing larger eggs and larger clutch sizes. While egg size is an important predictor of offspring quality, physiological factors within the egg yolk are reflective of the maternal environment and can alter offspring traits, especially during energetically costly processes, such as reproduction or immunity. Therefore, maternal effects may represent an adaptive mechanism by which urban-dwelling species can persist within a variable landscape. In this study, we assess urban and rural differences in egg yolk bacterial killing ability (BKA), corticosterone (CORT), oxidative status (d-ROMs), and energy metabolites (free glycerol and triglycerides), and their association with female immune status and egg quality. Within a laboratory setting, we immune challenged urban lizards via lipopolysaccharide injection (LPS) to test whether physiological changes associated with immune system activity impacted egg yolk investment. We found urban females had higher mite loads than rural females, however mite burden was related to yolk BKA in rural eggs, but not urban eggs. While yolk BKA differed between urban and rural sites, egg mass and egg viability (fertilized vs. unfertilized) were strong predictors of yolk physiology and may imply tradeoffs exist between maintenance and reproduction. LPS treatment caused a decrease in egg yolk d-ROMs relative to the control treatments, supporting results from previous research. Finally, urban lizards laid a higher proportion of unfertilized eggs, which differed in egg yolk BKA, CORT, and triglycerides in comparison to fertilized eggs. Because rural lizards laid only viable eggs during this study, these results suggest that reduced egg viability is a potential cost of living in an urban environment. Furthermore, these results help us better understand potential downstream impacts of urbanization on offspring survival, fitness, and overall population health.

The microbial environment modulates non-genetic maternal effects on egg immunity

Background

In a diverse microbial world immune function of animals is essential. Diverse microbial environments may contribute to extensive variation in immunological phenotypes of vertebrates, among and within species and individuals. As maternal effects benefit offspring development and survival, whether females use cues about their microbial environment to prime offspring immune function is unclear. To provide microbial environmental context to maternal effects, we asked if the bacterial diversity of the living environment of female zebra finches Taeniopygia guttata shapes maternal effects on egg immune function. We manipulated environmental bacterial diversity of birds and tested if females increased immunological investment in eggs in an environment with high bacterial diversity (untreated soil) versus low (gamma-sterilized soil). We quantified lysozyme and ovotransferrin in egg albumen and IgY in egg yolk and in female blood, and we used 16S rRNA gene sequencing to profile maternal cloacal and eggshell microbiotas.

Results

We found a maternal effect on egg IgY concentration that reflected environmental microbial diversity: females who experienced high diversity deposited more IgY in their eggs, but only if maternal plasma IgY levels were relatively high. We found no effects on lysozyme and ovotransferrin concentrations in albumen. Moreover, we uncovered that variation in egg immune traits could be significantly attributed to differences among females: for IgY concentration in yolk repeatability R = 0.80; for lysozyme concentration in albumen R = 0.27. Furthermore, a partial least squares path model (PLS-PM) linking immune parameters of females and eggs, which included maternal and eggshell microbiota structures and female body condition, recapitulated the treatment-dependent yolk IgY response. The PLS-PM additionally suggested that the microbiota and physical condition of females contributed to shaping maternal effects on egg immune function, and that (non-specific) innate egg immunity was prioritized in the environment with low bacterial diversity.

Conclusions

The microbial environment of birds can shape maternal effects on egg immune function. Since immunological priming of eggs benefits offspring, we highlight that non-genetic maternal effects on yolk IgY levels based on cues from the parental microbial environment may prove important for offspring to thrive in the microbial environment that they are expected to face.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-022-00195-8.

Parental methyl-enhanced diet and in ovo corticosterone affect first generation Japanese quail (Coturnix japonica) development, behaviour and stress response

The role of maternal investment in avian offspring has considerable life history implications on production traits and therefore potential for the poultry industry. A first generation (G₁) of Japanese quail (Coturnix japonica) were bred from a 2 × 2 factorial design. Parents were fed either a control or methyl-enhanced (HiBET) diet, and their eggs were treated with a vehicle or corticosterone injection during day 5 of incubation. A subset of G₁ birds were subjected to an open field trial (OFT) and capture-restraint stress protocol. Significant effects of HiBET diet were found on parental egg and liver weights, G₁ hatch, liver and female reproductive tract weights, egg productivity, latency to leave the OFT central zone, male baseline 11-dehydrocorticosterone, and female androstenedione plasma concentrations. In ovo treatment significantly affected latency to return to the OFT, male baseline testosterone and androstenedione, and change in androstenedione plasma concentration. Diet by treatment interactions were significant for G₁ liver weight and male baseline plasma concentrations of corticosterone. These novel findings suggest significant positive effects on reproduction, growth, precociousness, and hypothalamic-pituitary-adrenal axis function from enhanced methyl diets, and are important in understanding how in ovo stressors (representing maternal stress), affect the first offspring generation.

Maternal effects in mammals: Broadening our understanding of offspring programming

The perinatal period is a sensitive time in mammalian development that can have long-lasting consequences on offspring phenotype via maternal effects. Maternal effects have been most intensively studied with respect to two major conditions: maternal diet and maternal stress. In this review, we shift the focus by discussing five major additional maternal cues and their influence on offspring phenotype: maternal androgen levels, photoperiod (melatonin), microbiome, immune regulation, and milk composition. We present the key findings for each of these topics in mammals, their mechanisms of action, and how they interact with each other and with the maternal influences of diet and stress. We explore their impacts in the contexts of both predictive adaptive responses and the developmental origins of disease, identify knowledge gaps and research opportunities in the field, and place a particular emphasis on the application and consideration of these effects in non-model species and natural ecological systems.

Factor Influences for Diagnosis and Vaccination of Avian Infectious Bronchitis Virus (Gammacoronavirus) in Chickens

Infectious bronchitis virus (IBV) is a major economic problem in commercial chicken farms with acute multiple-system infection, especially in respiratory and urogenital systems. A live-attenuated and killed vaccine is currently immunized to control IBV infection; however, repeated outbreaks occur in both unvaccinated and vaccinated birds due to the choice of inadequate vaccine candidates and continuous emergence of novel infectious bronchitis (IB) variants and failure of vaccination. However, similar clinical signs were shown in different respiratory diseases that are essential to improving the diagnostic assay to detect IBV infections. Various risk factors involved in the failure of IB vaccination, such as various routes of application of vaccination, the interval between vaccinations, and challenge with various possible immunosuppression of birds are reviewed. The review article also highlights and updates factors affecting the diagnosis of IBV disease in the poultry industry with differential diagnosis to find the nature of infections compared with non-IBV diseases. Therefore, it is essential to monitor the common reasons for failed IBV vaccinations with preventive action, and proper diagnostic facilities for identifying the infective stage, leading to earlier control and reduced economic losses from IBV disease.

Effects of different mating strategies in broiler breeder during peak and postpeak phase on subsequent broiler performance

Two experimental trials on commercial broiler (Ross-308) were conducted to evaluate the carryover effect of artificial insemination (AI) in parent flock (PF) kept in cages (C), and on floor (F) in comparison to natural mating (NM) in floored PF. A total of 900 broiler chicks were obtained from 38-week-old PF (peak production), representing C, F, and NM evenly during first trial, whereas in second trial, similar number of chicks were obtained from same PF during postpeak phase (55 wk of age). Subsequent effects of AI and NM in PF were evaluated by bacteriology, posthatch mortality, growth performance, immune response, and carcass traits on experimental birds (broiler). Chicks being produced through NM exhibited significantly (P ≤ 0.05) improved growth performance (feed conversion ratio, weight gain, European efficiency factor) along with the least (P ≤ 0.05) posthatch mortality and prevalence of Escherichia coli, Salmonella Pullorum, and Mycoplasma gallisepticum. Moreover, the experimental chicks obtained from floored PF subjected to AI particularly during postpeak phase expressed the highest (P ≤ 0.05) contamination of the said pathogens along with posthatch mortality. However, immune response against New Castle disease and infectious bronchitis vaccines and slaughtering parameters remained nonsignificant (P > 0.05) among the 3 treatments under both trials. It is concluded that the best growth performance along with the least depletion and microbial load of concerned pathogens were being pertained by the experimental birds representing NM.

Economic contribution of local hatchery performance in the poultry value chain in Ghana

This research evaluates the effectiveness of local hatcheries in producing quality broiler day-old chicks in Ghana. A total of 600 Cobb 500 unsexed day-old broiler chicks obtained from 3 local hatcheries were raised for 6 wk with recommended starter and finisher diets from a registered source. The parameters measured included feed intake, body weights, body weight gain, feed conversion ratio, percent mortality, and haemagglutination inhibition test against Newcastle Disease virus and Infectious Bursal Disease virus (IBDv) during the first 2 wk. At the end of the study, 2 birds from each hatchery were selected and slaughtered to assess carcass parameters and primal parts including shank, neck, and head. Data were analyzed using the GLM Procedure of SAS 9.4 at P < 0.05 and LS means separated by the PDIFF of SAS. Results indicated that with the exception of the initial weight of the chicks, all other parameters were not different between the 3 hatcheries. The maternal antibody titre against IBDv was higher for all chicks but the response to Newcastle Disease virus and IBDv was relatively low in 1 hatchery. It could be concluded that the sources of chicks influenced initial chick weight but not the post-hatch performance. There is concern about the maternal antibodies levels of the chicks, which could be due to lack of appropriate and efficient vaccination of chicks.

Live attenuated duck hepatitis virus vaccine in breeder ducks: Protective efficacy and kinetics of maternally derived antibodies

Duck viral hepatitis type I is a rapidly spreading infection lethal in young ducklings, caused by the duck hepatitis A virus (DHAV). Vaccination of breeder ducks is a common practice to control DHAV. However, maintaining proper maternal antibody levels in large flocks is difficult. Therefore, a simple vaccination strategy that can induces stable high antibody levels through mass vaccination is desirable. We evaluated a DHAV vaccination strategy for breeder ducks involving oral administration under field conditions, and examined the kinetics of antibody response in the ducks and their progeny. The strategy included a primary intramuscular vaccination, followed by secondary and tertiary oral vaccinations. Five weeks after the primary vaccination, virus-neutralizing antibody titers increased by 8.4 ± 1.3 log₂. The titers remained stable at around 9.0 ± 1.1 log₂ for up to 36 weeks. None of the progeny died when challenged with virulent DHAV at 1, 7 or 14 days of age. The transfer percentage of antibodies from the breeder ducks to their progeny was 12.8 ± 3.0%. When antibody levels of the progeny were measured from the day of hatching to 20 days of age, the levels steadily declined, reaching a mean titer of 0 log₂ at 20 days. The half-life of the maternally derived antibodies against DHAV was 3.4 ± 1.1 days. Our vaccination strategy might be effective in breeder ducks because it can be easily applied and induced strong immunity. Moreover, our results might provide a foundation for the mechanistic study of maternally derived antibodies in passive protection.

Testing hypotheses for maternal effects in Daphnia magna

Maternal effects are widely observed, but their adaptive nature remains difficult to describe and interpret. We investigated adaptive maternal effects in a clone of the crustacean Daphnia magna, experimentally varying both maternal age and maternal food and subsequently varying food available to offspring. We had two main predictions: that offspring in a food environment matched to their mothers should fare better than offspring in unmatched environments, and that offspring of older mothers would fare better in low food environments. We detected numerous maternal effects, for example offspring of poorly fed mothers were large, whereas offspring of older mothers were both large and showed an earlier age at first reproduction. However, these maternal effects did not clearly translate into the predicted differences in reproduction. Thus, our predictions about adaptive maternal effects in response to food variation were not met in this genotype of Daphnia magna.