Publications by authors named "Hoogerwerf M"

Background: Shigella infections remain endemic in places with poor sanitation and are a leading cause of diarrheal mortality globally, as well as a major contributor to gut enteropathy and stunting. There are currently no licensed vaccines for shigellosis but it has been estimated that an effective vaccine could avert 590,000 deaths over a 20-year period. A challenge to effective Shigella vaccine development has been the low immunogenicity and protective efficacy of candidate Shigella vaccines in infants and young children.

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Article Synopsis
  • The study explores the motivations and decision-making factors of participants in SARS-CoV-2 vaccine trials, focusing on whether financial compensation affects their willingness to participate.
  • It involved administering surveys both before and after trial participation, with a 75% response rate, and found that most participants were driven by altruistic reasons like wanting to contribute to science.
  • Results showed no significant differences in responses before and after participation, suggesting that recall bias was not an issue, and the findings highlight a complex and diverse set of motivations influencing clinical trial participation.
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Hookworm infection remains a significant public health concern, particularly in low- and middle-income countries, where mass drug administration has not stopped reinfection. Developing a vaccine is crucial to complement current control measures, which necessitates a thorough understanding of host immune responses. By leveraging controlled human infection models and high-dimensional immunophenotyping, here we investigated the immune remodeling following infection with 50 Necator americanus L3 hookworm larvae in four naïve volunteers over two years of follow-up and compared the profiles with naturally infected populations in endemic areas.

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Schistosomiasis is an infection caused by contact with -contaminated water and affects more than 230 million people worldwide with varying morbidity. The roles of T helper 2 (T2) cells and regulatory immune responses in chronic infection are well documented, but less is known about human immune responses during acute infection. Here, we comprehensively map immune responses during controlled human infection using male or female cercariae.

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Tick-borne encephalitis is a vaccine-preventable disease of concern for public health in large parts of Europe, with EU notification rates increasing since 2018. It is caused by the orthoflavivirus tick-borne encephalitis virus (TBEV) and a diagnosis of infection is mainly based on serology due to its short viremic phase, often before symptom onset. The interpretation of TBEV serology is hampered by a history of orthoflavivirus vaccination and by previous infections with related orthoflaviviruses.

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Background: Vaccine development against hookworm is hampered by the absence of the development of protective immunity in populations repeatedly exposed to hookworm, limiting identification of mechanisms of protective immunity and new vaccine targets. Immunisation with attenuated larvae has proven effective in dogs and partial immunity has been achieved using an irradiated larvae model in healthy volunteers. We aimed to investigate the protective efficacy of immunisation with short-term larval infection against hookworm challenge.

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Schistosomiasis is a parasitic disease affecting over 200 million people in multiple organs, including the lungs. Despite this, there is little understanding of pulmonary immune responses during schistosomiasis. Here, we show type-2 dominated lung immune responses in both patent (egg producing) and pre-patent (larval lung migration) murine Schistosoma mansoni (S.

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Tick-borne encephalitis virus (TBEV) may cause tick-borne encephalitis (TBE), a potential life-threatening infection of the central nervous system in humans. Phylogenetically, TBEVs can be subdivided into three main subtypes, which differ in endemic region and pathogenic potential. In 2016, TBEV was first detected in the Netherlands.

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Wild and domestic animals can be usefully employed as sentinels for the surveillance of diseases with an impact on public health. In the case of tick-borne encephalitis virus (TBEV), the detection of antibodies in animals can be more effective than screening ticks for detecting TBEV foci, due to the patchy distribution of the virus. In the Piedmont region, northwestern Italy, TBEV is considered absent, but an increase in tick densities, of in particular, has been observed, and TBEV is spreading in bordering countries, e.

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Systemic immunosuppressive therapy (IS) renders patients with inflammatory bowel disease (IBD) vulnerable to fulminant hepatitis B virus (HBV) infection. Seroprotection against HBV through a full vaccination scheme is preferably obtained before IS is initiated, but often conflicts with the clinical need to initiate therapy rapidly. Consequently, the vast majority of patients will use IS during booster vaccinations.

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This study investigated the dynamics of SARS-CoV-2 infection and diagnostics in 242 household members of different ages and with different symptom severity after SARS-CoV-2 exposure early in the pandemic (March-April 2020). Households with a SARS-CoV-2 confirmed positive case and at least one child in the Netherlands were followed for 6 weeks. Naso (NP)- and oropharyngeal (OP) swabs, oral fluid and feces specimens were analyzed for SARS-CoV-2 RNA and serum for SARS-CoV-2-specific antibodies.

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Controlled human infection studies, in which small groups of health volunteers are exposed to an infectious agent, contribute significantly to the tropical infectious diseases research field. Not only can these studies be used to quickly and efficiently test new vaccines or drugs, but they can also lead to new insights into the pathophysiology and immunology of these infectious diseases. When designing a controlled human infection study, many important ethical and methodological considerations should be taken into account.

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We compared the performance of SARS-CoV-2 neutralising antibody testing between 12 European laboratories involved in convalescent plasma trials. Raw titres differed almost 100-fold differences between laboratories when blind-testing 15 plasma samples. Calibration of titres in relation to the reference reagent and standard curve obtained by testing a dilution series reduced the inter-laboratory variability ca 10-fold.

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Article Synopsis
  • Hookworm is a significant global health issue affecting over 230 million people, but can potentially be eliminated through vaccines and mass drug administration.
  • A stakeholders meeting in Lamberene, Gabon, was held to discuss the establishment of Controlled Hookworm Human Infection (CHHI) studies, emphasizing the importance of regulatory capacity, ethical guidelines, and community considerations.
  • The meeting aimed to address challenges in implementing CHHI in Gabon and hopes to foster interest in using this model in sub-Saharan Africa for tackling hookworm.
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Orthohantaviruses (family , order ) can cause two serious syndromes in humans: hemorrhagic fever with renal syndrome (HFRS), associated with the Old World orthohantaviruses, and hantavirus cardiopulmonary syndrome (HCPS), associated with orthohantaviruses in the Americas. In Europe, four different orthohantaviruses (DOBV, PUUV, SEOV, and TULV) are associated with human disease. As disease severity and zoonotic source differ between orthohantavirus species, conclusive determination of the infecting species by either RT-PCR or comparative virus neutralization test (VNT) is of importance.

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Hookworms are soil-transmitted helminths that use immune-evasive strategies to persist in the human duodenum where they are responsible for anemia and protein loss. Given their location and immune regulatory effects, hookworms likely impact the bacterial microbiota. However, microbiota studies struggle to deconvolute the effect of hookworms from confounders such as coinfections and malnutrition.

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To understand SARS-CoV-2 immunity after natural infection or vaccination, functional assays such as virus neutralising assays are needed. So far, assays to detect SARS-CoV-2 neutralising antibodies rely on cell-culture based infection assays either using wild type SARS-CoV-2 or pseudotyped viruses. Such assays are labour-intensive, require appropriate biosafety facilities and are difficult to standardize.

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Objective: To quantitatively investigate the motivations, decision-making and experience of participants in controlled human infection (CHI) studies.

Design: Cross-sectional descriptive survey study.

Setting: Previous participants of CHI studies at the Leiden Controlled Human Infection Center, control group of students from Leiden University.

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Background: Controlled human hookworm infections could significantly contribute to the development of a hookworm vaccine. However, current models are hampered by low and unstable egg output, reducing generalizability and increasing sample sizes. This study aims to investigate the safety, tolerability, and egg output of repeated exposure to hookworm larvae.

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Immunization with attenuated sporozoites can induce protection against malaria infection, as shown by (Pf) sporozoites attenuated by radiation in multiple clinical trials. As alternative attenuation strategy with a more homogeneous population of Pf sporozoites (PfSPZ), genetically engineered sporozoites (SPZ) lacking the genes b9 and slarp induced sterile protection against malaria in mice. Consequently, PfSPZ-GA1 Vaccine, a Pf identical double knockout (Pf∆∆), was generated as a genetically attenuated malaria parasite vaccine and tested for safety, immunogenicity, and preliminary efficacy in malaria-naïve Dutch volunteers.

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Schistosomiasis treatment relies on the use of a single drug, praziquantel, which is insufficient to control transmission in highly endemic areas. Novel medicines and vaccines are urgently needed. An experimental human model for schistosomiasis could accelerate the development of these products.

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Four healthy volunteers were infected with 50 Necator americanus infective larvae (L3) in a controlled human hookworm infection trial and followed for 52 weeks. The kinetics of fecal egg counts in volunteers was assessed with Bayesian multilevel analysis, which revealed an increase between weeks 7 and 13, followed by an egg density plateau of about 1000 eggs/g of feces. Variation in egg counts was minimal between same-day measurements but varied considerably between days, particularly during the plateau phase.

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Despite frequent records from other parts of the North Atlantic, minke whales have never been acoustically recorded in the North Sea. This study investigated the detectability of pulse trains previously associated with this species in other regions, in acoustic data from ten sites along the east coast of Scotland. Since preliminary results confirmed pulse train presence, subsequently, an automated detector was applied to these data to record the seasonal and diel presence of minke whale pulse trains.

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