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Effects of age and environment on adaptive immune responses to Mycobacterium avium subsp. paratuberculosis (MAP) vaccination in dairy goats in relation to paratuberculosis control strategies
Koets, Ad ; Ravesloot, Lars ; Ruuls, Robin ; Dinkla, Annemieke ; Eisenberg, Susanne ; Lievaart-Peterson, Karianne - \ 2019
Veterinary Sciences 6 (2019)3. - ISSN 2306-7381
Diagnostics - Immunity - Mycobacterium - Paratuberculosis - Vaccination
Paratuberculosis infection is caused by Mycobacterium avium subsp. paratuberculosis (MAP). In the Netherlands, 75% herd level prevalence of caprine paratuberculosis has been estimated, and vaccination is the principal control strategy applied. Most goat dairy farms with endemic paratuberculosis systematically vaccinate goat kids in the first months of life with a commercially available whole cell MAP vaccine. We hypothesized that the development of adaptive immune responses in goats vaccinated at young age depends on the environment they are raised in, and this has implications for the application of immune diagnostic tests in vaccinated dairy goats. We evaluated the early immune response to vaccination in young goat kids sourced from a MAP unsuspected non-vaccinated herd and raised in a MAP-free environment. Subsequently we compared these with responses observed in birth year and vaccination matched adult goats raised on farms with endemic paratuberculosis. Results indicated that initial adaptive immune responses to vaccination are limited in a MAP-free environment. In addition, adult antibody positive vaccinated goats raised in a MAP endemic environment are less likely to be IS900 PCR-positive as compared to antibody negative herd mates. We conclude that test-and-cull strategies in a vaccinated herd are currently not feasible using available immune diagnostic tests.
Knowledge, attitudes and practices of cervical cancer prevention among Zambian women and men
Nyambe, Anayawa ; Kampen, Jarl K. ; Baboo, Stridutt K. ; Hal, Guido Van - \ 2019
BMC Public Health 19 (2019)1. - ISSN 1471-2458
Attitude - Cervical cancer - Knowledge - Practices - Screening - Social ecological model - Theory of triadic influence - Vaccination - Zambia
Background: In Zambia, cervical cancer screening was started in 2006 and the human papillomavirus vaccine was piloted in 2013. Nevertheless, cervical cancer remains the leading cancer. It is assumed that knowledge, social interaction, health behaviors and religion are factors that can influence screening and vaccination practices. This study addresses the question, what is the relationship between knowledge about cervical cancer, attitudes, self-reported behavior, and immediate support system, towards screening and vaccination of cervical cancer of Zambian women and men. The results of this study serve as a basis for future research, an input for improvement and adjustment of the existing prevention program and build on documented health behavior frameworks. Methods: A cross-sectional mixed methods study was conducted from February to May 2016. Two separate questionnaires were used to collect data from women (N = 300) and men (N = 300) residing in Chilenje and Kanyama (two townships in the capital city Lusaka). Respondent's knowledge of cervical cancer was operationalized by grading their ability to correctly identify causes and protective factors if they were aware of cervical cancer. Besides providing descriptive statistics of all study variables, we tested four research hypotheses concerning the link between knowledge, attitudes and practices suggested by the literature, by applying appropriate statistical tests (chi square test, analysis of variance, logistic regression). Results: Less than half of the respondents (36.8%) had heard of cervical cancer, 20.7% of women had attended screening and 6.7% of the total sample had vaccinated their daughter. Knowledge of causes and prevention was very low. There was a strong association between having awareness of cervical cancer and practicing screening (odds ratio = 20.5, 95% confidence interval = [9.214, 45.516]) and vaccination (odds ratio = 5.1, 95% confidence interval = [2.473, 10.423]). Social interactions were also found to greatly influence screening and vaccination behaviors. Conclusions: The low level of knowledge of causes and prevention of cervical cancer suggests a need to increase knowledge and awareness among both women and men. Interpersonal interactions have great impact on practicing prevention behaviors, for instance, vaccination of daughters.
A systematic evaluation of measures against highly pathogenic avian influenza (HPAI) in Indonesia
Pramuwidyatama, Muchammad Gumilang ; Hogeveen, Henk ; Saatkamp, Helmut W. - \ 2019
Frontiers in Veterinary Science 6 (2019)FEB. - ISSN 2297-1769
Endemic - Evaluation - HPAI H5N1 - Measures - Mitigation - Strategy - Vaccination
Over the past years, many different control measures have been implemented to prevent HPAI infection. The national plan with numerous measures lead to problems in terms of prioritization and budget allocation. Our study objectives are to (i) establish an inventory of measures on HPAI control in Indonesia since the first actions were taken in 2004, (ii) evaluate preferences for different HPAI control measures applied in the West Java province at the district level during 2013-2017, and (iii) establish a basis for further qualitative and quantitative research to improve control for an endemic HPAI in Indonesia. This research was carried out according to the following five steps (i) development of an HPAI management framework for an endemic state, (ii) inventorization of measures directed at HPAI and description of the development of HPAI in Indonesia, (iii) development of a questionnaire for the experts involved, (iv) systematic evaluation of preferences for short- and long-term HPAI strategies and measures applied in the West Java Province based on expert opinion, and (v) data analysis. The study systematically evaluated in total 27 measures. The results of this study show that the animal disease management framework is helpful as a systematic structure to distinguish and evaluate strategies and measures. In our framework, we defined the following strategies: prevention, monitoring, control, mitigation, eradication, and human protection. The findings of our research show that the primary aims of the government were to safeguard humans from HPAI transmission by mitigating HPAI disease in livestock. The measures with the highest priority were preventive vaccination of poultry, biosecurity, and stamping-out infected flocks. This showed that the government predominantly chose a vaccination-based HPAI mitigation strategy. However, the chosen strategy has a low implementation feasibility. A collaboration between the responsible stakeholders farmers may increase the feasibility of the chosen strategy in the future. Furthermore, our findings provide a basis for research into the motivation of farmers to implement different measures as well as into the expected impact of different measures to develop an effective and efficient mitigation approach.
The impact of the social environment on Zambian cervical cancer prevention practices
Nyambe, Anayawa ; Kampen, Jarl K. ; Baboo, Stridutt K. ; Hal, Guido Van - \ 2018
BMC Cancer 18 (2018). - ISSN 1471-2407
Cervical Cancer - Screening - Social ecological model - Theory of triadic influence - Vaccination - Zambia
Background: Cervical cancer which is preventable by screening and vaccination is the most common cancer in Zambia among both the female and male population. In this article we aim to determine how the key players of the sociocultural and political environment recognize cervical cancer as a public health problem and therefore impact the provision of cervical cancer prevention services (screening and vaccination). Methods: Qualitative data in the form of interviews with stakeholders (health care providers, teachers and religious leaders), special interest groups (advocacy groups and non-governmental organizations) and policy makers, was collected as part of a mixed methods study from February to May 2016. Results: The views expressed by the respondents were coded into predetermined themes (cervical cancer in general, screening, vaccination) and an organizational chart of the administration of cervical cancer prevention services in Zambia was developed. Conclusions: It is evident that the Zambian cervical cancer prevention system has targeted several areas and multiple sectors of society to reduce cervical cancer cases. However, awareness, knowledge, social support and facilities are factors that can be improved.
Economic impact of lumpy skin disease and cost effectiveness of vaccination for the control of outbreaks in Ethiopia
Molla, Wassie ; Jong, Mart C.M. de; Gari, Getachew ; Frankena, Klaas - \ 2017
Preventive Veterinary Medicine 147 (2017). - ISSN 0167-5877 - p. 100 - 107.
Economic loss - Ethiopia - LSD outbreak - Morbidity - Mortality - Vaccination
Lumpy skin disease (LSD), an infectious viral disease of cattle, causes considerable financial losses in livestock industry of affected countries. A questionnaire survey with the objectives of determining direct economic losses of LSD (mortality loss, milk loss, draft loss) and treatment costs (medication and labour cost) per affected herd, and assessing the cost effectiveness of vaccination as a means for LSD control was carried out in the central and north-western parts of Ethiopia. From a total of 4430 cattle (in 243 herds) surveyed, 941 animals (in 200 herds) were reported to be infected. The overall morbidity and mortality at animal level were 21.2% and 4.5%, and at herd level these were 82.3% and 24.3%. There was a significant difference in animal level morbidity and mortality between categories of animals. Over 94% of the herd owners ranked LSD as a big or very big problem for cattle production. A large proportion (92.2%) of the herd owners indicated that LSD affects cattle marketing. A median loss of USD 375 (USD 325 in local Zebu and USD 1250 in Holstein-Friesian local Zebu cross cattle) was estimated per dead animal. Median losses per affected lactating cow were USD 141 (USD 63 in local Zebu cows and USD 216 in Holstein-Friesian local Zebu cross cows) and, USD 36 per affected ox. Diagnosis and medication cost per affected animal were estimated at USD 5. The median total economic loss of an LSD outbreak at herd level was USD 1176 (USD 489 in subsistence farm and USD 2735 in commercial farm). At herd level, the largest component of the economic loss was due to mortality (USD 1000) followed by milk loss (USD 120). LSD control costs were the least contributor to herd level losses. The total herd level economic losses in the commercial farm type were significantly higher than in the subsistence farm type. The financial analysis showed a positive net profit of USD 136 (USD 56 for subsistence farm herds and USD 283 for commercial herds) per herd due to LSD vaccine investment. It should be noted that only the noticeable direct costs and treatment costs associated with the disease were considered in the study. Generally, vaccination is economically effective and should be encouraged.
Foot-and-Mouth Disease Seroprevalence in Cattle in Eritrea
Tekleghiorghis, T. ; Weerdmeester, K. ; Hemert-Kluitenberg, Froukje van; Moormann, R.J.M. ; Dekker, Aldo - \ 2017
Transboundary and Emerging Diseases 64 (2017)3. - ISSN 1865-1674 - p. 754 - 763.
Administrative regions - Eritrea - Foot-and-mouth disease virus - Seroprevalence - Serotypes - Vaccination
Information about seroprevalence of foot-and-mouth disease (FMD) and virus serotypes in Eritrea is unavailable, but is very important as it may guide the choice of intervention measures including vaccination to be implemented. We carried out a cross-sectional study from February to June 2011 in Eritrea with a two-stage cluster design, sampling cattle in 155 villages with the objective of determining the seroprevalence of FMD in four administrative regions of the country. We analysed cattle sera (n = 2429) for FMD virus antibodies using the non-structural ELISA (NS ELISA) and virus neutralization test (VNT). The overall seroprevalence was 26% and 30% for the NS ELISA and VNT, respectively. FMD virus serotypes O (14%) and A (11%) were the most prevalent. Gash Barka showed the highest (39%) seroprevalence both in NS ELISA and VNT compared to the other three administrative regions. Strategic FMD virus vaccination with type O and A (matching circulating strains) in combination of zoo-sanitary measures would be the best control option for Eritrea which could be started in areas where the disease is less endemic.
Host-Derived Cytokines and Chemokines as Vaccine Adjuvants
Degen, W.G.J. ; Schijns, Virgil E.J.C. - \ 2016
In: Immunopotentiators in Modern Vaccines: Second Edition Elsevier Inc. Academic Press - ISBN 9780128040195 - p. 65 - 84.
Adjuvant - Chemokine - Cytokine - Prophylactic - Therapeutic - Vaccination
The increased knowledge about immunological concepts and systems nowadays helps to rationally enhance the performance of, and to overcome some of the problems, that are associated with inactivated vaccines. Because the antigenic component of an inactivated vaccine by itself only gives a limited or no activation of the immune system, the addition of an adjuvant is required to induce a strong and an adequate type of immune response. However, this may be associated with unacceptable local reactions. To overcome this safety issue and to further enhance the performance of "first-generation" adjuvants, research is currently addressing new types of adjuvants that are both safe and strong. A solution for the generation of safe and strong adjuvants without unwanted, or minimal, local reactions can be found within the use of the so-called host-derived immunostimulating or modulating molecules, e.g., intercellular signaling molecules like cytokines and cell traffic-directing chemokines. As these molecules are host derived, and therefore often species specific, they have been shown to induce highly acceptable local reactions (if any) in contrast to many "first-generation" adjuvants. Proper efficacy of these molecular adjuvants requires optimal dosing and timing.
Screening and vaccination as determined by the Social Ecological Model and the Theory of Triadic Influence : a systematic review
Nyambe, Anayawa ; Hal, Guido Van; Kampen, Jarl K. - \ 2016
BMC Public Health 16 (2016). - ISSN 1471-2458 - 15 p.
Multi-level ecological models - Screening - Social Ecological Model - Theory of Triadic Influence - Vaccination
Background: Vaccination and screening are forms of primary and secondary prevention methods. These methods are recommended for controlling the spread of a vast number of diseases and conditions. To determine the most effective preventive methods to be used by a society, multi-level models have shown to be more effective than models that focus solely on individual level characteristics. The Social Ecological Model (SEM) and the Theory of Triadic Influence (TTI) are such models. The purpose of this systematic review was to identify main differences and similarities of SEM and TTI regarding screening and vaccination in order to prepare potentially successful prevention programs for practice. Methods: A systematic review was conducted. Separate literature searches were performed during January and February 2015 using Medline, Ovid, Proquest, PubMed, University of Antwerp Discovery Service and Web of Science, for articles that apply the SEM and TTI. A Data Extraction Form with mostly closed-end questions was developed to assist with data extraction. Aggregate descriptive statistics were utilized to summarize the general characteristics of the SEM and TTI as documented in the scientific literature. Results: A total of 290 potentially relevant articles referencing the SEM were found. As for the TTI, a total of 131 potentially relevant articles were found. After strict evaluation for inclusion and exclusion criteria, 40 SEM studies and 46 TTI studies were included in the systematic review. Conclusions: The SEM and TTI are theoretical frameworks that share many theoretical concepts and are relevant for several types of health behaviors. However, they differ in the structure of the model, and in how the variables are thought to interact with each other, the TTI being a matrix while the SEM has a ring structure. The main difference consists of the division of the TTI into levels of causation (ultimate, distal and proximal) which are not considered within the levels of the SEM. It was further found that in the articles studied in this systematic review, both models are often considered effective, while the empirical basis of these (and other) conclusions reached by their authors is in many cases unclear or incompletely specified.
Mutations in the haemagglutinin protein and their effect in transmission of highly pathogenic avian influenza (HPAI) H5N1 virus in sub-optimally vaccinated chickens
Sitaras, Ioannis ; Rousou, Xanthoula ; Peeters, Ben ; Jong, Mart C.M. de - \ 2016
Vaccine 34 (2016)46. - ISSN 0264-410X - p. 5512 - 5518.
Epidemiology - H5N1 - HA - Influenza - Mutations - Transmission - Vaccination
Background Transmission of highly pathogenic avian influenza (HPAI) viruses in poultry flocks is associated with huge economic losses, culling of millions of birds, as well as human infections and deaths. In the cases where vaccination against avian influenza is used as a control measure, it has been found to be ineffective in preventing transmission of field strains. Reports suggest that one of the reasons for this is the use of vaccine doses much lower than the ones recommended by the manufacturer, resulting in very low levels of immunity. In a previous study, we selected for immune escape mutants using homologous polyclonal sera and used them as vaccines in transmission experiments. We concluded that provided a threshold of immunity is reached, antigenic distance between vaccine and challenge strains due to selection need not result in vaccine escape. Here, we evaluate the effect that the mutations in the haemagglutinin protein of our most antigenically-distant mutant may have in the transmission efficiency of this mutant to chickens vaccinated against the parent strain, under sub-optimal vaccination conditions resembling those often found in the field. Methods In this study we employed reverse genetics techniques and transmission experiments to examine if the HA mutations of our most antigenically-distant mutant affect its efficiency to transmit to vaccinated chickens. In addition, we simulated sub-optimal vaccination conditions in the field, by using a very low vaccine dose. Results We find that the mutations in the HA protein of our most antigenically-distant mutant are not enough to allow it to evade even low levels of vaccination-induced immunity. Discussion Our results suggest that – for the antigenic distances we investigated – vaccination can reduce transmission of an antigenically-distant strain compared to the unvaccinated groups, even when low vaccine doses are used, resulting in low levels of immunity.
Effect of culling and vaccination on bovine tuberculosis infection in a European badger (Meles meles) population by spatial simulation modelling
Abdou, Marwa ; Frankena, Klaas ; O'Keeffe, James ; Byrne, Andrew W. - \ 2016
Preventive Veterinary Medicine 125 (2016). - ISSN 0167-5877 - p. 19 - 30.
Agent-based model - Culling - Meles meles - Mycobacterium bovis - Spatially-explicit model - Vaccination
The control of bovine tuberculosis (bTB) in cattle herds in the Republic of Ireland (ROI) is partially hindered by spill-back infection from wild badgers (Meles meles). The aim of this study was to determine the relative effects of interventions (combinations of culling and/or vaccination) on bTB dynamics in an Irish badger population. A spatial agent-based stochastic simulation model was developed to evaluate the effect of various control strategies for bovine tuberculosis in badgers: single control strategies (culling, selective culling, vaccination, and vaccine baits), and combined strategies (Test vaccinate/cull (TVC)), split area approaches using culling and vaccination, or selective culling and vaccination, and mixed scenarios where culling was conducted for five years and followed by vaccination or by a TVC strategy. The effect of each control strategy was evaluated over a 20-year period. Badger control was simulated in 25%, 50%, and 75% area (limited area strategy) or in the entire area (100%, wide area strategy). For endemic bTB, a culling strategy was successful in eradicating bTB from the population only if applied as an area-wide strategy. However, this was achieved only by risking the extinction of the badger population. Selective culling strategies (selective culling or TVC) mitigated this negative impact on the badger population's viability. Furthermore, both strategies (selective culling and TVC) allowed the badger population to recover gradually, in compensation for the population reduction following the initial use of removal strategies. The model predicted that vaccination can be effective in reducing bTB prevalence in badgers, when used in combination with culling strategies (i.e. TVC or other strategies). If fecundity was reduced below its natural levels (e.g. by using wildlife contraceptives), the effectiveness of vaccination strategies improved. Split-area simulations highlighted that interventions can have indirect effects (e.g. on population size) in non-treatment areas. Our model suggests that mixed control strategies could maintain infection prevalence to a low level for a considerable period even with a growing population. The model supported the hypothesis that culling strategies appeared to be the most effective method for the control of bTB in badgers using parameters, where available, from ROI, either singly or in combination with other strategies. In this model, the success of a vaccination strategy depended partially upon population density and the proportion of the population infected, therefore an initial culling program (to reduce density and/or remove infected badgers) followed by long-term vaccination may be effective in controlling bTB in badgers.
Controlling highly pathogenic avian influenza outbreaks : An epidemiological and economic model analysis
Backer, J.A. ; Roermund, H.J.W. van; Fischer, E.A.J. ; Asseldonk, M.A.P.M. van; Bergevoet, R.H.M. - \ 2015
Preventive Veterinary Medicine 121 (2015)1-2. - ISSN 0167-5877 - p. 142 - 150.
Control strategy - Economic assessment - Epidemiological model - Highly pathogenic avian influenza - HPAI - Pre-emptive culling - Vaccination
Outbreaks of highly pathogenic avian influenza (HPAI) can cause large losses for the poultry sector and for animal disease controlling authorities, as well as risks for animal and human welfare. In the current simulation approach epidemiological and economic models are combined to compare different strategies to control highly pathogenic avian influenza in Dutch poultry flocks. Evaluated control strategies are the minimum EU strategy (i.e., culling of infected flocks, transport regulations, tracing and screening of contact flocks, establishment of protection and surveillance zones), and additional control strategies comprising pre-emptive culling of all susceptible poultry flocks in an area around infected flocks (1. km, 3. km and 10. km) and emergency vaccination of all flocks except broilers around infected flocks (3. km).Simulation results indicate that the EU strategy is not sufficient to eradicate an epidemic in high density poultry areas. From an epidemiological point of view, this strategy is the least effective, while pre-emptive culling in 10. km radius is the most effective of the studied strategies. But these two strategies incur the highest costs due to long duration (EU strategy) and large-scale culling (pre-emptive culling in 10. km radius). Other analysed pre-emptive culling strategies (i.e., in 1. km and 3. km radius) are more effective than the analysed emergency vaccination strategy (in 3. km radius) in terms of duration and size of the epidemics, despite the assumed optimistic vaccination capacity of 20 farms per day. However, the total costs of these strategies differ only marginally. Extending the capacity for culling substantially reduces the duration, size and costs of the epidemic.This study demonstrates the strength of combining epidemiological and economic model analysis to gain insight in a range of consequences and thus to serve as a decision support tool in the control of HPAI epidemics.