Public Health Threat of New, Reemerging, and Neglected Zoonoses in the Industrialized World

Microbiologic infections acquired from animals, known as zoonoses, pose a risk to public health. An estimated 60% of emerging human pathogens are zoonotic. Of these pathogens, >71% have wildlife origins. These pathogens can switch hosts by acquiring new genetic combinations that have altered pathogenic potential or by changes in behavior or socioeconomic, environmental, or ecologic characteristics of the hosts. We discuss causal factors that influence the dynamics associated with emergence or reemergence of zoonoses, particularly in the industrialized world, and highlight selected examples to provide a comprehensive view of their range and diversity

Beheersing van het Schmallenbergvirus

Schmallenbergvirus (SVB) werd in 2011 voor het eerst in Europa gezien en veroorzaakte een epidemie van aangeboren afwijkingen, vooral misvormde ledematen en hersenafwijkingen, bij kalveren en lammeren. Het ging om een niet eerder gevonden virus, dat om die reden aanvankelijk moeilijk onderkend kon worden. Sinds het begin van de uitbraak is veel onderzoek gedaan aan SVB en inmiddels zijn routine laboratoriumtests alom beschikbaar. Zowel gehouden als in het wild levende herkauwers zijn gevoelig voor het SVB, dat wordt overgedragen door knutten (Culicoides species). Deze vector heeft gezorgd voor een snelle verspreiding over heel Europa en nu verspreidt het virus zich ook buiten Europa. Op dit moment wordt de economische schade ten gevolge van SVB vooral bepaald door handelsbeperkingen. Levend vee en sperma voor export moeten getest worden om het SVB-vrij te kunnen verklaren. In de regio waar de uitbraak is begonnen, wordt de ziekte niet meer gezien, maar met de toename van het aantal seronegatieve dieren wordt het risico van herintroductie van het virus op bedrijven wellicht groter

Schmallenberg virus : technical and scientific studies

Schmallenberg virus primarily infects domestic and wild ruminants. Cattle and sheep seem to be the most susceptible species. Goats, pigs and camelids seem to be less susceptible. In pregnant cattle and sheep, the virus can infect multiple organs of the un-borne fetus. However, this infection often does not cause major lesions and infrequently leads to malformations

Het Centraal Veterinair Instituut versterkt het onderzoek naar opkomende zoönosen

Een zoönose is een infectieziekte die overgedragen kan worden van gewervelde dieren naar mensen of omgekeerd. Ruim 60 procent van de ziekteverwekkers bij mensen heeft een zoönotisch karakter. Het verkleinen van het risico van zoönosen voor de mens is één van de taken van het CVI. Samen met diverse partners richt het CVI zich op het vroegtijdig opsporen van deze ziekteverwekkers in het dierlijk reservoir en op het ontwikkelen van bestrijdingsmethoden. Het CVI is referentiecentrum voor aangifteplichtige dierziekten inclusief zoönosen en voert onderzoeksprojecten uit op het gebied van dierziektebestrijding voor zowel de overheid als in opdracht van externe partijen en in (inter)nationale samenwerkingsverbanden. Onderzoek aan zoönosen is daar een belangrijk onderdeel van. Ten behoeve van een betere preventie, opsporing en bestrijding van zoönosen wil het CVI het onderzoek naar opkomende zoönosen versterken. Een aantal voorbeelden van zoönosen waar het CVI aan werkt, wordt kort besproken

First detection of kobuvirus in farm animals in Brazil and the Netherlands.

Animal kobuviruses have been described in pigs, cattle, sheep and bats in countries in Asia and Europe. The virus can be detected in fecal and serum samples of infected animals with or without diarrhea, but most of the clinical as well as epidemiological features of kobuvirus infection are still unknown. This study reports the first detection of kobuvirus in farm animals from Brazil and the Netherlands and the molecular analysis of the detected strains. In Brazil, 53% (61/115) of the pigs (suckling, weaned and sows) were shedding porcine kobuvirus in feces, while in the Netherlands 16.7% (3/18) of the tested weaned pigs were infected. Kobuviruses detected in fecal samples of pigs in Brazil showed association (p = 0.0002) with diarrhea. In pig serum, kobuvirus was detected at different ages (3, 21, 36, 60, 75, and 180 days), with an overall rate of 76.7% (23/30). The sequencing of amplicons detected in serum of pigs of different ages suggested reinfection and no persistent infection. Kobuvirus was also detected in sheep and cattle feces from Brazil and the Netherlands, respectively. Phylogenetic analyses of Brazilian and Dutch kobuviruses from pig, cattle and sheep revealed genetic variability, particularly in one strain detected in sheep feces, which was more closely related to human Aichi virus. The molecular and phylogenetic analyses performed with other published kobuvirus strains and the strains presented in this study, showed that, in most of the cases, kobuvirus seems to group according to host species, but not to geographical region of origin. The data presented in this study contribute to the comprehension of kobuvirus epidemiology and also to the molecular identification of kobuvirus strains circulating worldwide

Age-dependent differences in the pathogenesis of bovine respiratory syncytial virus infections related to the development of natural immunocompetence

The severity of respiratory syncytial virus (RSV) infections appears to differ with age in both humans and bovines. A primary RSV infection in naïve infants and in young calves runs a more severe course when they are 1–6 months old than in their first month of life. The relative lack of clinical signs in the first month of age may be due to high levels of maternally derived neutralizing antibodies or low exposure to infectious virus. This study examined whether age-dependent differences in the pathogenesis of bovine RSV (bRSV) between neonatal and young calves may be due to differences in age-dependent immunocompetence. To study the effect of age and immune parameters on bRSV disease in neonatal and young calves, neonatal (1-day-old) calves without maternally derived antibodies were infected experimentally with bRSV and the severity of disease and immune responses were evaluated in comparison with disease in similar 6-week-old infected calves. Neonatal calves had more extensive virus replication and lung consolidation, but lower pro-inflammatory [in particular tumour necrosis factor alpha (TNF-{alpha})] responses, specific humoral immune responses, lung neutrophilic infiltration and clinical signs of disease than 6-week-old calves. The lack of correlation between virus replication and clinical signs suggests an important role of pro-inflammatory cytokines, in particular TNF-{alpha}, in the disease. The capacity to produce pro-inflammatory TNF-{alpha} appeared to increase with age, and may explain the age-dependent differences in RSV pathogenesis

Development and application of a SYBR Green RT-PCR for first line screening and quantification of porcine sapovirus infection

BACKGROUND: Sapoviruses are single stranded positive sense RNA viruses belonging to the family Caliciviridae. The virus is detected in different species including the human and the porcine species as an enteric pathogen causing asymptomatic to symptomatic enteritis. In this study, we report the development of a rapid real time qRT-PCR based on SYBR Green chemistry for the diagnosis of porcine sapovirus infection in swine. RESULTS: The method allows the detection of porcine sapoviruses and the quantification of the genomic copies present in stool samples. During its development, the diagnostic tool showed good correlation compared with the gold standard conventional RT-PCR and was ten-fold more sensitive. When the method was applied to field samples, porcine noroviruses from genogroup 2 genotype 11b were also detected. The method was also applied to swine samples from the Netherlands that were positive for PoSaV infection. Phylogenetic results obtained from the samples showed that PoSaV sequences were genetically related to the currently described genogroup III, to the proposed genogroup VII and also to the MI-QW19 sequence (close to the human SaV sequences). CONCLUSIONS: A rapid, sensitive, and reliable diagnosis method was developed for porcine sapovirus diagnosis. It correlated with the gold standard conventional RT-PCR. Specificity was good apart for genogroup 2 genotype 11b porcine noroviruses. As a first line screening diagnosis method, it allows a quicker and easier decision on doubtful samples

Development and Validation of a Genotype 3 Recombinant Protein based Immunoassay for Hepatitis E Virus Serology in Swine

Hepatitis E virus (HEV) is classified within the family Hepeviridae, genus Hepevirus. HEV genotype 3 (Gt3) infections are endemic in pigs in Western Europe and in North and South America and cause zoonotic infections in humans. Several serological assays to detect HEV antibodies in pigs have been developed, at first mainly based on HEV genotype 1 (Gt1) antigens. To develop a sensitive HEV Gt3 ELISA, a recombinant baculovirus expression product of HEV Gt3 open reading frame-2 was produced and coated onto polystyrene ELISA plates. After incubation of porcine sera, bound HEV antibodies were detected with anti-porcine anti-IgG and anti-IgM conjugates. For primary estimation of sensitivity and specificity of the assay, sets of sera were used from pigs experimentally infected with HEV Gt3. For further validation of the assay and to set the cutoff value, a batch of 1100 pig sera was used. All pig sera were tested using the developed HEV Gt3 assay and two other serologic assays based on HEV Gt1 antigens. Since there is no gold standard available for HEV antibody testing, further validation and a definite setting of the cutoff of the developed HEV Gt3 assay were performed using a statistical approach based on Bayes' theorem. The developed and validated HEV antibody assay showed effective detection of HEV-specific antibodies. This assay can contribute to an improved detection of HEV antibodies and enable more reliable estimates of the prevalence of HEV Gt3 in swine in different regions

Hepatitis E Virus in Pork Liver Sausage, France

We investigated viability of hepatitis E virus (HEV) identified in contaminated pork liver sausages obtained from France. HEV replication was demonstrated in 1 of 4 samples by using a 3-dimensional cell culture system. The risk for human infection with HEV by consumption of these sausages should be considered to be high