Alexandre Dobly

Sciensano · Biological Health Risks

At present, quality control of diphtheria vaccines by both manufacturers and national control laboratories relies heavily on in vivo assays to confirm potency. As part of the VAC2VAC project we have developed a monoclonal antibody (mAb) enzyme-linked immunosorbent assay (ELISA) to measure the relative amount and quality of diphtheria toxoid (DTxd)...

Routine batch quality testing before vaccine release, notably for potency evaluation, still relies on animal use for several animal and human vaccines. In this context, the VAC2VAC project is a public-private consortium of 22 partners funded by EU whose the main objective is to reduce the number of animal used for batch testing by developing immuno...

Even though Listeria monocytogenes is an extensive-studied foodborne pathogen, genome analysis of isolates from snails that may represent a reservoir of L. monocytogenes are still scarce. Here, we use whole-genome sequencing (WGS) to assess the genomic diversity of hypervirulent, virulent and non-virulent phenotypes of 15 L. monocytogenes isolated...

The tetanus neurotoxin (TeNT) is one of the most toxic proteins known to man, which prior to the use of the vaccine against the TeNT producing bacteria Clostridium tetani, resulted in a 20 % mortality rate upon infection. The clinical detrimental effects of tetanus have decreased immensely since the introduction of global vaccination programs, whic...

The tetanus neurotoxin (TeNT) is one of the most toxic proteins known to man, which prior to the use of the vaccine against the TeNT producing bacteria Clostridium tetani, resulted in a 20% mortality rate upon infection. The clinical detrimental effects of tetanus have decreased immensely since the introduction of global vaccination programs, which...

Batch release testing for human and veterinary tetanus vaccines still relies heavily on methods that involve animals, particularly for potency testing. The quantity and quality of tetanus antigen present in these products is of utmost importance for product safety and clinical effect. Immunochemical methods that measure consistency of antigen conte...

Immunoassays are used for routine potency assessment of several vaccines, in some cases having been specifically developed as alternatives to in vivo potency tests. These methods require at least one well characterised monoclonal antibody (mAb) that is specific for the target antigen. In this paper we report the results of the comprehensive charact...

Within the Innovative Medicines Initiative 2 (IMI 2) project VAC2VAC (Vaccine batch to vaccine batch comparison by consistency testing), a workshop has been organised to discuss ways of improving the design of multi-centre validation studies and use the data generated for product-specific validation purposes. Moreover, aspects of validation within...

Maternal antibodies induced by vaccination during pregnancy cross the placental barrier and can close the susceptibility gap to pertussis in young infants up to the start of primary immunization. As not only the quantity but also the quality of circulating antibodies is important for protection, we assessed whether maternal immunization affects the...

Introduction: In order to investigate the role of roe deer in the maintenance and transmission of infectious animal and human diseases in Flanders, we conducted a serologic screening in 12 hunting areas. Materials and methods: Roe deer sera collected between 2008 and 2013 (n=190) were examined for antibodies against 13 infectious agents, using i...

The bovine spongiform encephalopathy (BSE) epidemics have led to active surveillance in Europe. Detection methods are focused on the obex, where prions fi rst accumulate in the central nervous system (CNS). Sampling is made with a calibrated syringe (from Bio-Rad or Idexx) that must sample a target area in the obex area. This study checked the prec...

In sheep, the susceptibility to scrapie is mainly determined by the codons 136, 154 and 171 of the PRNP. Five haplotypes are usually present (ARR, ARQ, ARH, AHQ and VRQ). The ARR haplotype confers the highest resistance to classical scrapie, while VRQ is the most susceptible. In 2004, the European Union implemented a breeding program that promotes...

The transmission of pathogens to susceptible hosts is dependent on the vector population dynamics. In Europe, bank voles (Myodes glareolus) carry Puumala hantavirus, which causes nephropathia epidemica (NE) in humans. Fluctuations in bank vole populations and epidemics in humans are correlated but the main factors influencing this relationship rema...

1 Eenheid Coördinatie van Diergeneeskundige Diagnose, Epidemiologie and Risico Analyse (CDD-ERA), Operatio-nele Directie Interacties en Bewaking, Centrum voor Onderzoek in Diergeneeskunde en Agrochemie (CODA-CER-VA), Brussel, België ; 2 Eenheid Pathologie & Prionologie, Operationele Directie Interacties en Bewaking, Centrum voor Onderzoek in Dierge...

Several vole species use scent marked runways radiating from their burrows for foraging and dispersion. These marks are probably used for social communication. This 4-day laboratory study investigated the environmental and social causations of marking inside pre-existing corridors in male and female common volesMicrotus arvalis (Pallas, 1778). Firs...

Tick-borne encephalitis virus (TBEV) is an important emerging tick-borne viral infection of humans and dogs in Europe. Currently, TBEV surveillance is virtually nonexistent in Belgium, which is considered nonendemic. A commercial enzyme-linked immunosorbent assay (ELISA) was adapted for the detection of TBEV-specific IgG-antibodies in canine sera....

Hantaviruses are worldwide rodent-borne pathogens infecting humans and other animals mainly through inhalation of aerosols contaminated with rodent excreta. Few data are available on hantavirus serology and geographical distribution in dogs and cats. We therefore screened sera from pet dogs (N=410) and cats (N=124) in two regions of Belgium, using...

The bovine spongiform encephalopathy (BSE) epidemic presented homogeneity of the phenotype. This classical BSE (called C-type) was probably due to the contamination of the food chain by a single prion strain. However, due to the active surveillance and better techniques, two rare variants of BSE have been recently reported in different continents w...

Western blots of the sample previously published. Western blots comparing the sample previously published in [17] with reference samples of L-, C-, and experimental H-type isolates.

Female common voles can breed in small groups or in isolation. Given the option, will isolated females opt for communal breeding with unrelated females and a probable low reproductive bias, or will they remain isolated, forgoing the advantages of group living? This laboratory work examined the response of two unrelated females to a foreign male in...

Listeria monocytogenes is an important foodborne pathogen both in humans and animals. In order to determine the presence and importance of this zoonotic bacterial disease in a subgroup of the Belgian cattle population, all the brain tissue specimens originating from 2,432 cattle clinically suspected of bovine spongiform encephalopathy (BSE) that ha...

In order to determine the habitat preferred by Myodes (before Clethrionomys) glareolus and the corresponding Puumala hantavirus seroprevalence in those habitats, we captured rodents simultaneously in three significantly different habitats. We compared trapping success and presence of virus per habitat during an ongoing epidemic in order to test the...

Quantitative genetic analyses of fish composition have been strongly biased towards lipid deposition, rather than protein deposition. This is partly at odds with desires of the modern aquaculture industry, to improve the efficiency of lean growth. Using a quantitative genetic approach, we examined the selection potential in both protein and lipid c...

This study examines the way long-term feed intake should be recorded accurately for selective breeding purposes, and estimates selection potential in feed intake using the X-ray method to record individual daily feed intake in rainbow trout (Oncorhynchus mykiss). The analysis showed that the point estimates of daily feed intake displayed low repeat...

Abstract This study examines the way long-term feed intake should be recorded accurately for selective breeding purposes, and estimates selection potential in feed intake using the X-ray method to record individual daily feed intake in rainbow trout (Oncorhynchus mykiss). The analysis showed that the point estimates of daily feed intake displayed l...

The efficiency with which fish and other animals add and maintain body proteins is a balance between synthesis of proteins and their degradation. In fish that have similar food consumption and protein synthesis rates, a greater ratio of synthesis to degradation would be expected to produce more efficient conversion of food into growth. In addition,...

Common voles use networks of runways around their burrows, which are dug in meadows. Their orientation among such networks could be based on "egocentred" routes (possibly through the use of olfactory "trails") or on more general, "allocentred" spatial representations (with distant visual cues). In this 5-day study, male voles should reach food in t...

The common spiny mice Acomys dimidiatus and golden spiny mice Acomys russatus coexist in the extreme warm and dry parts of the Rift Valley in Israel. However, they are temporally segregated in that the former is nocturnal, whereas the latter is diurnal. Daily rhythms of physiological and behavioral variables in A. russatus responded to semiochemica...

Female common voles live in groups in large burrows whereas males are probably solitary and promiscuous. At high population density, when burrows become a limiting factor, some females are forced to emigrate from their group. To investigate whether these emigrants could share new common burrows with unrelated neighbours, we analysed in the laborato...