Herd Immunization Research Articles

COVID-19 Vaccine Hesitancy among the Population of Quetta—Associated Beliefs and Barriers

Objectives: This study aimed to determine the prevalence of hesitancy towards COVID-19 vaccination among the adult population of Quetta and the likelihood predictors of hesitancy towards COVID-19 vaccination. Study Design: Analytical cross-sectional study. Place and Duration of Study: Study was conducted at Quetta, from Nov 2021 to May 2022. Methodology: A total of 396 individuals participated in the study. Along with socio-demographic details, participants responded to the COVID-VAX scale and questions from WHO determinants of vaccine-hesitancy. A relationship was modelled between WHO determinants of vaccine-hesitancy, socio-demographic characteristics and vaccine-hesitancy using logistic regression. Results: Results showed that majority of individuals were vaccine-hesitant (67.2%). The final model obtained significant predictors among contextual influences as demonstrated past bad experiences on vaccination, non-belief in risking their own and family’s health for being non-vaccinated and negative influences by an influential person. Among individual influences,knowledge about someone having bad experiences to vaccines, confusion about scheduling of vaccines, lack of trust in the healthcare system and provider, disbelieving in immunization as a social norm and concerns regarding vaccine. Among factors directly related to vaccine/vaccination, difficult vaccination schedule, fear of pain/needles, and non-willingness to pay for vaccination were found as significant predictors of the COVID-19 vaccine-hesitancy (p-value <0.05). Conclusions: More than half of the participants showed hesitancy towards COVID-19 vaccine. Factors contributing to vaccinehesitancy must be addressed to build confidence regarding COVID-19 vaccines among the people to attain the goal of herd immunization against COVID-19.

Seroprevalence of hepatitis B and hepatitis C virus among clinically suspected cases of viral hepatitis visiting Guhalla Primary Hospital, Northwest Ethiopia

Hepatitis B virus and hepatitis C virus remains one of the leading causes of morbidity and mortality worldwide, particularly in countries with limited resources. The two hepatotropic viruses have common mode of transmission. Hepatitis B virus and hepatitis C virus are the main causes of Cirrhosis, liver cancer and death. To determine the Seroprevalence of HBsAg and anti-HCV antibodies among clinically suspected cases of viral hepatitis visiting Guhalla Primary Hospital, Northwest Ethiopia. A hospital-based retrospective study was conducted at Guhalla Primary Hospital, Northwest Ethiopia. The study included serology registration logbook data from all patients who visited the hospital and were tested using a rapid test kit between September 1st, 2017 to August 30, 2021. Data were entered, cleaned, and analyzed using SPSS version 26 software. Bivariate analysis was computed and a multivariable analysis was conducted to provide an adjusted odds ratio (AOR). p-value < 0.05 at a 95% confidence interval was considered statistically significant. In this study, a total of 883(883 for HBV and 366 for HCV) study participants were included. The overall prevalence of HBsAg and anti-HCV were 124/883(14%) and 73/366 (19.9%), respectively. The prevalence of HBV and HCV among males from the total HBV and HCV screened was 70/410 (17.1%) and 53/366(14.4%) respectively. In this study, being female (AOR 1.53, 95% CI 1.03–2.27, p = 0.003) and age group of 31–40 years (AOR 2.85; 95% CI 1.56, 5.17, p = 0.001) were statistically significant factors to HBV infection. Similarly, being female (AOR 1.97, 95% CI 1.10–3.53, p = 0.02), age group of 21–30 years (AOR 2.71; 95% CI 1.15, 6.40, p = 0.02) and age group greater than 40 years (AOR 3.13; 95% CI 1.31, 7.44, p = 0.01) were significantly associated with HCV infection. In our study, high seroprevalence of HBV and HCV infection was detected among clinically suspected patients. Females and the age groups between 31 and 40 were more affected. Community awareness of the prevention and transmission of viral hepatitis infection should be strengthened through herd immunization and health education. The prospective study should be conducted in this area.

Assessing vulnerability for future Zika virus outbreaks using seroprevalence data and environmental suitability maps.

The 2015-17 Zika virus (ZIKV) epidemic in the Americas subsided faster than expected and evolving population immunity was postulated to be the main reason. Herd immunization is suggested to occur around 60-70% seroprevalence, depending on demographic density and climate suitability. However, herd immunity was only documented for a few cities in South America, meaning a substantial portion of the population might still be vulnerable to a future Zika virus outbreak. The aim of our study was to determine the vulnerability of populations to ZIKV by comparing the environmental suitability of ZIKV transmission to the observed seroprevalence, based on published studies. Using a systematic search, we collected seroprevalence and geospatial data for 119 unique locations from 37 studies. Extracting the environmental suitability at each location and converting to a hypothetical expected seroprevalence, we were able to determine the discrepancy between observed and expected. This discrepancy is an indicator of vulnerability and divided into three categories: high risk, low risk, and very low risk. The vulnerability was used to evaluate the level of risk that each location still has for a ZIKV outbreak to occur. Of the 119 unique locations, 69 locations (58%) fell within the high risk category, 47 locations (39%) fell within the low risk category, and 3 locations (3%) fell within the very low risk category. The considerable heterogeneity between environmental suitability and seroprevalence potentially leaves a large population vulnerable to future infection. Vulnerability seems to be especially pronounced at the fringes of the environmental suitability for ZIKV (e.g. Sao Paulo, Brazil). The discrepancies between observed and expected seroprevalence raise the question: "why did the ZIKV epidemic stop with large populations unaffected?". This lack of understanding also highlights that future ZIKV outbreaks currently cannot be predicted with confidence.

Voluntary vaccination on hypergraph

In reality, when epidemics spread, higher-order interactions in group settings such as homes and schools, for example, can make infections more likely to occur. People often voluntarily get vaccinated to protect themselves and other members of their group from infection. On the other hand, there are individuals who want to “free-ride” and try to avoid infection through herd immunization. Thus, it is clear that vaccination is influenced by both individuals and groups. However, in existing studies, vaccination behavior is often determined only by individual’s self-payoff, with little consideration of group influences. Here, we propose a model of vaccination on a hypergraph. In our model, self-payoff and group-payoff together influence the vaccination. Evolutionary game theory is used to explore the differences in individual vaccination behavior when group-payoff are prioritized versus self-payoff are prioritized. The mean-field method is utilized for theoretical analysis. The experimental results show that at low adoption strength, vaccine cost determines vaccination. When adoption strength is high, priority is given to group-payoff to promote vaccination. If individuals place a extremely high value on self-payoff and have a high strength of adoption, they only vaccinate when the cost of vaccination is as low as zero. Yet, after the rates of infection is high enough, individuals choose to get vaccinated regardless of whether they care more about self-payoff or group-payoff.

Impact of COVID-19 Vaccination on Pregnant Women.

In light of the COVID-19 pandemic, researchers across the world hastened to develop vaccines that would aid in bolstering herd immunity. Utilizing mRNA coding and viral vector technology, the currently approved vaccines were required to undergo extensive testing to confirm their safety for mass usage in the general population. However, clinical trials failed to test the safety and efficacy of the COVID-19 vaccines in groups with weakened immune systems, especially pregnant women. Lack of information on the effects of vaccinations in pregnancy and the safety of fetuses are among the topmost reasons preventing pregnant women from receiving immunization. Thus, the lack of data examining the effects of COVID-19 vaccinations on pregnant women must be addressed. This review focused on the safety and efficacy of the approved COVID-19 vaccinations in pregnancy and their impact on both maternal and fetal immune responses. For that, we took the approach of combined systematic review/meta-analysis and compiled the available data from the original literature from PubMed, Web of Science, EMBASE and Medline databases. All articles analyzed presented no adverse effects of vaccination in pregnancy, with varying conclusions on the degree of effectiveness. The majority of the findings described robust immune responses in vaccinated pregnant women, successful transplacental antibody transfer, and implications for neonatal immunity. Hence, findings from the cumulative data available can be helpful in achieving COVID-19 herd immunization, including pregnant women.

Challenges in Engendering Herd Immunity to SARS-CoV-2 Infection: Possibly Impossible But Plausibile.

Herd immunity can only be achieved when it is extended to the population level. When a sufficiently significant fraction of immune individuals exists in a group, it confers indirect protection from infection to vulnerable individuals. This population-level effect is frequently considered in the context of vaccination programs, which attempt to build herd immunity so that people who cannot be vaccinated, such as the very young or those with impaired immune systems, are nonetheless protected from disease. Clinical signs are at times poor predictor of transmissibility for some infections, such as COVID-19, because asymptomatic hosts can be extremely infectious and contribute to the spread of the virus. COVID-19 is a quickly evolving issue that has been widely spread throughout the world. This article elaborates the idea and goal of herd immunity, the necessary conditions for realizing herd immunity, the restrictive requirements for applying herd immunity, and the obstacles experienced in achieving herd immunity in the context of COVID-19. This mini-article explains the concept and purpose of herd immunization in the context of COVID-19.

COVID-19 vaccine hesitancy among different population groups in China: a national multicenter online survey

BackgroundCOVID-19 vaccine has been available in China since the beginning of the 2021, however, certain numbers of people are reluctant for some reasons to vaccinate. The high vaccine coverage is crucial for controlling disease transmission, however, the vaccine hesitancy might be a barrier to the establishment of sufficient herd immunization. This study aims to investigate the prevalence of the COVID-19 vaccine hesitancy among different population groups, and explore common barriers and facilitators to vaccination decisions.MethodsThe current survey was performed among Chinese students, public health professionals, medical workers and general population from January to March 2021 from seven cities in China. The questionnaire contained sociodemographic information, concerns about infection with COVID-19, general vaccination behaviors and attitudes, the General Vaccine Hesitancy Scale, the COVID-19 Vaccine Hesitancy Scale and other potential factors. Univariate analysis was conducted by chi-squared test, and variables significant at P < 0.10 were then included in a multivariable regression model.ResultsThe prevalence of COVID-19 vaccine hesitancy was 15.6% in our study, and 23.9% of students, 21.2% of the general population, 13.1% of medical workers, and 10.4% of public health professionals had vaccine hesitancy. The results of multivariate analysis indicated that participants who had received negative information of COVID-19 vaccine (OR: 1.563, 95% CI: 1.229–1.986) and who had doubts about the information source (OR: 2.157, 95% CI: 1.697–2.742) were more likely to have vaccine hesitancy. While those who needed transparent information about COVID-19 vaccine (OR: 0.722, 95% CI: 0.535–0.973) and who would get COVID-19 vaccine if doctors recommended (OR: 0.176, 95% CI: 0.132–0.234) were less likely to have COVID-19 vaccine hesitancy.ConclusionsGiven recommendations from medical workers about vaccination can motivate people to accept COVID-19 vaccination, appropriate training in knowledge about vaccines and communication skills are necessary for them to increase public’s willingness of vaccination. Reducing the spread of misinformation and disseminating facts in a timely and accurate way will likely reduce vaccine hesitancy. Moreover, to establish suitable communication strategies and information exchange platforms between the government and the public and a warning system on infodemic would be helpful to improve public’s confidence in vaccination.

Immunization against severe acute respiratory syndrome Coronavirus 2: an overview.

In the past years, numerous new fatal infections have emerged, including Ebola, Nipah, and Zika viruses, as well as coronaviruses. Recently, infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have emerged in China, and were then transmitted all over the world, causing the coronavirus disease-19 (COVID-19) pandemic, which is transmitted at a higher rate than other diseases caused by coronaviruses. At the time of writing this review, COVID-19 is not contained in most countries in spite of quarantine, physical distancing, and enhanced hygiene measures. In this review, I address different methods for passive and active immunization against this virus, which is known to cause fatal respiratory disease, including natural passive immunization by breast milk, natural active immunization by herd immunization, artificial passive immunization by convalescent plasma or monoclonal antibodies, and artificial active immunization by vaccination. I hope this review will help design a prophylactic approach against outbreaks and pandemics of related coronaviruses in the future.

A dynamical map to describe COVID-19 epidemics.

Nonlinear dynamics perspective is an interesting approach to describe COVID-19 epidemics, providing information to support strategic decisions. This paper proposes a dynamical map to describe COVID-19 epidemics based on the classical susceptible-exposed-infected-recovered (SEIR) differential model, incorporating vaccinated population. On this basis, the novel map represents COVID-19 discrete-time dynamics by adopting three populations: infected, cumulative infected and vaccinated. The map promotes a dynamical description based on algebraic equations with a reduced number of variables and, due to its simplicity, it is easier to perform parameter adjustments. In addition, the map description allows analytical calculations of useful information to evaluate the epidemic scenario, being important to support strategic decisions. In this regard, it should be pointed out the estimation of the number deaths, infection rate and the herd immunization point. Numerical simulations show the model capability to describe COVID-19 dynamics, capturing the main features of the epidemic evolution. Reported data from Germany, Italy and Brazil are of concern showing the map ability to describe different scenario patterns that include multi-wave pattern with bell shape and plateaus characteristics. The effect of vaccination is analyzed considering different campaign strategies, showing its importance to control the epidemics.

Navigating ethics in a pandemic—Contempt for the weak versus love of neighbor in a Swedish lens

AbstractThe article draws on the author's observations and reflections about Sweden's pandemic management from February 2020 to June 2021. It does not simply interpret the lessons one can learn from the Swedish biopolitical experiment, but focuses on some central ethical challenges that every nation had to face in an accelerating pandemic. The intention with such a sharp critical discussion of the Swedish experience is to clarify some of the crucial ethical dilemmas and abysses in pandemic ethics. One article cannot possibly cover the wide and deep agenda for all complex ethical dimensions in a pandemic. This contribution in particular explores why the method of natural herd immunization is unethical, and what kind of legal and ethical aspects are relevant in international law and the WHO's ethical codex for a pandemic. In a Christian perspective it seems not at all strange to approach the theme of pandemic ethic also with theological arguments. A creator God who became flesh is deeply involved in our bodily world and life. What counts as health therefore appears to be a central issue for believers and faith communities, as is faith in a God who bodily cares for and liberates God's creation in all its dimensions. The exploration of Sweden's pandemic experiment flows into a plea for to apply the triple command of love sharpened by the command of love of the poor and vulnerable, and concludes with a short meta‐ethical reflection on the need of aesth/ethical imagination of the other.

Reasonable Limiting of 7-Day Incidence per Hundred Thousand and Herd Immunization in Germany and Other Countries

Based on hospital capacities, facts from past experience with the coronavirus disease 2019 (COVID-19) virus and the number of dark infections during the second wave (DII=2D2), a reasonable limiting value of 140/D2 for the 7-day incidence per 100,000 persons (MSDIHT) and a second wave herd immunization threshold fraction value of 0.26 in Germany were calculated. If the MSDIHT is held below this limiting value, the German hospital system can cope with the number of new seriously infected persons without any triage decisions. On the basis of the SIRV epidemics model, the classical threshold values for herd immunization were calculated for 18 countries. For these countries, the dates regarding when herd immunization against the second COVID-19 wave will be reached were estimated.

PRRSV2 genetic diversity defined by RFLP patterns in the United States from 2007 to 2019.

The genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) increases over time. In 1998, restriction-fragment length polymorphism (RFLP) pattern analysis was introduced to differentiate PRRSV wild-type strains from VR2332, a reference strain from which a commercial vaccine (Ingelvac PRRS MLV) was derived. We have characterized here the PRRSV genetic diversity within selected RFLP families over time and U.S. geographic space, using available ISU-VDL data from 2007 to 2019. The 40,454 ORF5 sequences recovered corresponded to 228 distinct RFLPs. Four RFLPs [2-5-2 (21.2%), 1-7-4 (15.6%), 1-4-4 (11.8%), and 1-8-4 (9.9%)] represented 58.5% of all ORF5 sequences and were used for cluster analysis. Over time, there was increased detection of RFLPs 2-5-2, 1-7-4, 1-3-4, 1-3-2, and 1-12-4; decreased detection of 1-4-2, 1-18-4, 1-18-2, and 1-2-2; and different detection trends for 1-8-4, 1-4-4, 1-26-1, 1-22-2, and 1-2-4. An over-time cluster analysis revealed a single cluster for RFLP 2-5-2, supporting that sequences within RFLP 2-5-2 are still relatively conserved. For 1-7-4, 1-4-4, and 1-8-4, there were multiple clusters. State-wise cluster analysis demonstrated 4 main clusters for RFLP 1-7-4 and 1-8-4, and 6 for RFLP 1-4-4. For the other RFLPs, there was a significant genetic difference within them, particularly between states. RFLP typing is limited in its ability to discriminate among different strains of PRRSV. Understanding the magnitude of genetic divergence within RFLPs helps develop PRRSV regional control programs, placement, herd immunization strategies, and design of appropriate animal movements across borders to minimize the risk of PRRSV transmission.

A Review of COVID-19 Mathematical Models and an Implementation of Vaccination Policies

Cellular automata (CA) models have been used to simulate the behaviour of infectious diseases and can offer valuable information concerning the spread of infection and population susceptibility to sickness. Furthermore, CA models can be used to evaluate various response strategies, such as herd immunization and vaccination. By assessing CA approaches for COVID-19, we identified a lack of an age-based symptom severity score and death probability (1-3). We used a Susceptible Infected Removed (SIR) model and distribution of population age groups from the Canadian government to determine the effect of vaccinating older (60+ years old) versus a younger population (30-59 years old). Our findings show a significant decrease in the total number of deaths and peak number of infections when the older population was vaccinated. This is a result of the higher probabilities of death and severe symptoms in older age groups. While this simulation is based on a small scale, the findings provide evidence to prioritize vaccination of the elderly.

A Novel Structure of Blockchain Applied in Vaccine Quality Control: Double-Chain Structured Blockchain System for Vaccine Anticounterfeiting and Traceability.

Background Vaccine, as an irreplaceable means in herd immunization, is widely applied in prevention for communicable diseases. However, adverse impacts were frequently incurred by fake or expired vaccines in China. Given the necessity of vaccine anticounterfeiting, blockchain-based transaction platform could be practiced as a solution in addressing the issue; however, most of the available experiments focused on single-chain structured design with inventible limitations. Accordingly, exploration for the effectiveness and feasibility of mixed-chains structured platform for vaccine anticounterfeiting and tracing is essentially required. Methods Both public chain and private chain were inserted in anticounterfeiting and tracing platform designing process, which were subsequently simulated in Ethereum environment. Results By recording different information in public chain and private chain, partial information privacy protection requirements are realized. The transfer identification module realized the function of vaccine quality supervision and solves the problem of EPC label replication. Discussion. Compared with the traditional single-structured design, completeness information could be visited by all stakeholders in double-chain structure, including vaccine suppliers, National Medical Products Administration (NMPA), vaccine purchasers, and the vaccinated. Conclusion Double-chain structured system for vaccine anticounterfeiting and tracing is more effective.

Risk of Secondary Infection Waves of COVID-19 in an Insular Region: The Case of the Balearic Islands, Spain.

The Spanish government declared the lockdown on March 14th, 2020 to tackle the fast-spreading of COVID-19. As a consequence, the Balearic Islands remained almost fully isolated due to the closing of airports and ports, these isolation measures and the home-based confinement have led to a low prevalence of COVID-19 in this region. We propose a compartmental model for the spread of COVID-19 including five compartments (Susceptible, Exposed, Presymptomatic Infective, Diseased, and Recovered), and the mobility between municipalities. The model parameters are calibrated with the temporal series of confirmed cases provided by the Spanish Ministry of Health. After calibration, the proposed model captures the trend of the official confirmed cases before and after the lockdown. We show that the estimated number of cases depends strongly on the initial dates of the local outbreak onset and the number of imported cases before the lockdown. Our estimations indicate that the population has not reached the level of herd immunization necessary to prevent future outbreaks. While the low prevalence, in comparison to mainland Spain, has prevented the saturation of the health system, this low prevalence translates into low immunization rates, therefore facilitating the propagation of new outbreaks that could lead to secondary waves of COVID-19 in the region. These findings warn about scenarios regarding after-lockdown-policies and the risk of second outbreaks, emphasize the need for widespread testing, and could potentially be extrapolated to other insular and continental regions.

Anti COVID-19 immunity developed as assessed in a community-based oncological center

Introduction: Serology (antibody) tests for the SARS-CoV-2 have been proposed as an instrument to inform health authorities about immunization during the COVID-19 pandemic. As there is a significant part of the population that may have some degree of immunity, it is of great interest to communicate the immunization results obtained in the first 500 healthcare workers (HCW), patients and relatives tested in a community-based Oncological Center. Materials and methods: Between April 9th, 2020 and May 8th, 2020, a group of healthcare workers (HCW), their families, and general public who had had the COVID-19 or had been in close contact with confirmed cases of COVID-19 were screened for IgG SARS-CoV-2 antibodies. The tests were carried out in a rigorous manner, strictly following the guidelines approved by the Spanish Ministry of Health (Ministerio de Sanidad). Results: The major objective of this study was to determine the proportion of asymptomatic infected individuals and those who had already secreted IgG against SARS-CoV-2 in our cancer treatment center or in the community of Barcelona. Patients were tested with PCR, Rapid diagnostic test (RDT) or enzyme-linked immunoabsorbent assay (ELISA). A total of 521 participants were tested, 206 with RDT and 315 with ELISA, 59 (11,32%) resulted positive to SARS-CoV-2. Conclusion: RDT and ELISA proved to be effective and sensible enough to determine the extent of SARS-CoV-2 immunization in a community-based oncological center. The degree of immunization reached is nowadays far away from what can be considered desirable for a herd immunization.

Herd immunization with childhood vaccination may provide protection against COVID-19.

It may take time to obtain a vaccine for the current COVID-19, and the virus genome may keep an evolution and mutations, so a universal and effective vaccine for the coronavirus may not be possible. Epidemiological studies reveal the infection of SARS and COVID-19 in children is less frequent and less severe than in adults. Childhood vaccine-mediated cross cellular immunity and immunomodulation might provide protection against the infections of COVID-19. These data suggest that herd immunization with children vaccines in adults may improve the adult cross cellular immunity and immunomodulation and improve their clinical presentation and prognosis. This can be also useful to cope with future pandemics.

Influence of vaccination against paratuberculosis on the diagnosis of caprine tuberculosis during official eradication programmes in Castilla y León (Spain)

The information generated from the official eradication programmes of caprine tuberculosis (TB) in Castilla y León, Spain, during 2018, has been used to assess the effect of vaccination against paratuberculosis (PTB) and the presence of this infection, on the single intradermal tuberculin (SIT) test results. Data from 121,665 goats belonging to 1936 different herds were analysed using generalized linear models. An epidemiological survey was conducted to know the herd immunization status against PTB and the date of last vaccination. All SIT test-positive animals were further investigated in order to confirm the diagnosis of TB, through bacterial culture, and PTB, by histopathological and qPCR analyses. SIT positivity was found in 39 (2.01%) herds and 507 (0.41%) goats. TB was confirmed by M.caprae or M.bovis isolation in 10 (0.51%) herds and 46 (0.038%) goats. PTB was diagnosed in 13 (33.33%) and 55 (10.84%) of the SIT test-positive herds and goats, respectively. Vaccination against PTB showed a significant influence on the results of the SIT test at herd level, with higher positivity detected among those herds vaccinated. However, this effect was not observed when the total number of animals was considered, where the highest positivity was found in unvaccinated goats. The time elapsed between vaccination and SIT test performance also influenced the results. The strongest effect was found when less than eight months elapsed between performing both activities, and to a lesser extent between 8 and 12months. Conversely, no positive herds or animals were found when the time elapsed was higher than one year. No significant effect of the presence of PTB was observed. These findings demonstrate that the use of PTB vaccine does not result in false positives to a SIT test at individual level, provided that the time elapsed between the performance of both practices is higher than 12months.

Toxocara canis infection may impair bovine herpesvirus type 5 immunization

Helminths have developed complex mechanisms to suppress the host immune response. These mechanisms may impair the host vaccine response. This study aimed to evaluate the effect of Toxocara spp. infection on the vaccine immune response to bovine herpesvirus type 5 (BoHV–5). First, 30 heifers received two doses of an experimental BoHV–5 vaccine. At 42nd days after the primo vaccination the vaccine efficacy was evaluated, and the presence of anti-Toxocara antibodies. Second, 20 Balb/c mice were divided into two groups, one infected with T. canis and the other without infection. After infection, both groups received two doses of vaccine. The vaccine immune response was assessed by BoHV-5 serum neutralization and splenic cytokines transcription by qPCR. All heifers positive for Toxocara spp. (40%) showed BoHV-5 SN titer ≤1:32, whereas heifers negative for Toxocara spp. (60%) had BoHV-5 SN titer ≥1: 128. Infected T. canis mice showed BoHV-5 SN titer ≤1:2, whereas mice not infected with T. canis BoHV-5 SN titer ≥1:8. Splenocytes from control mice stimulated with BoHV-5 had a significant (p < .05) mRNA transcription for the cytokines IL-12, IL-17, and IL-23, whereas the same cytokines were down-regulated in T. canis infected mice. These results suggest that Toxocara spp. infection may impair BoHV-5 immunization and should be considered for efficient herd immunization.

Assessment of abortion risk of sows on Japanese commercial farms infected with porcine epidemic diarrhea virus.

The objectives of this study were to assess abortion risk (AR) and the number of piglets that died during suckling periods per litter (DP) in farms infected with porcine epidemic diarrhea (PED) in relation to herd immunization procedures. Data were obtained from 91 farms in Japan that had PED infection during 2013 to 2014. The 91 PED-positive farms were asked the number of abortions that occurred and DP for 3months (1month before PED outbreak (previous month), 1month after PED outbreak (the month of PED), and from 1month after PED outbreak to 2months after PED outbreak (following month)). AR in each month was calculated as the number of abortions divided by sow inventory. Both AR and DP in the month of PED were higher than those in the previous and following months (p<.05). Farms that performed a herd immunization procedure had higher AR and DP in the month of PED than those that did not perform the procedure (p<.05). In summary, PED occurrence increased AR and DP.