Postnatal persistent infection with classical Swine Fever virus and its immunological implications.

It is well established that trans-placental transmission of classical swine fever virus (CSFV) during mid-gestation can lead to persistently infected offspring. The aim of the present study was to evaluate the ability of CSFV to induce viral persistence upon early postnatal infection. Two litters of 10 piglets each were infected intranasally on the day of birth with low and moderate virulence CSFV isolates, respectively. During six weeks after postnatal infection, most of the piglets remained clinically healthy, despite persistent high virus titres in the serum. Importantly, these animals were unable to mount any detectable humoral and cellular immune response. At necropsy, the most prominent gross pathological lesion was a severe thymus atrophy. Four weeks after infection, PBMCs from the persistently infected seronegative piglets were unresponsive to both, specific CSFV and non-specific PHA stimulation in terms of IFN-γ-producing cells. These results suggested the development of a state of immunosuppression in these postnatally persistently infected pigs. However, IL-10 was undetectable in the sera of the persistently infected animals. Interestingly, CSFV-stimulated PBMCs from the persistently infected piglets produced IL-10. Nevertheless, despite the addition of the anti-IL-10 antibody in the PBMC culture from persistently infected piglets, the response of the IFN-γ producing cells was not restored. Therefore, other factors than IL-10 may be involved in the general suppression of the T-cell responses upon CSFV and mitogen activation. Interestingly, bone marrow immature granulocytes were increased and targeted by the virus in persistently infected piglets. Taken together, we provided the first data demonstrating the feasibility of CSFV in generating a postnatal persistent disease, which has not been shown for other members of the Pestivirus genus yet. Since serological methods are routinely used in CSFV surveillance, persistently infected pigs might go unnoticed. In addition to the epidemiological and economic significance of persistent CSFV infection, this model could be useful for understanding the mechanisms of viral persistence.

Immune Responses Against Classical Swine Fever Virus: Between Ignorance and Lunacy.

Classical swine fever virus infection of pigs causes disease courses from life-threatening to asymptomatic, depending on the virulence of the virus strain and the immunocompetence of the host. The virus targets immune cells, which are central in orchestrating innate and adaptive immune responses such as macrophages and conventional and plasmacytoid dendritic cells. Here, we review current knowledge and concepts aiming to explain the immunopathogenesis of the disease at both the host and the cellular level. We propose that the interferon type I system and in particular the interaction of the virus with plasmacytoid dendritic cells and macrophages is crucial to understand elements governing the induction of protective rather than pathogenic immune responses. The review also concludes that despite the knowledge available many aspects of classical swine fever immunopathogenesis are still puzzling.

Intracellular membrane association of the N-terminal domain of classical swine fever virus NS4B determines viral genome replication and virulence.

Classical swine fever virus (CSFV) causes a highly contagious disease in pigs that can range from a severe haemorrhagic fever to a nearly unapparent disease, depending on the virulence of the virus strain. Little is known about the viral molecular determinants of CSFV virulence. The nonstructural protein NS4B is essential for viral replication. However, the roles of CSFV NS4B in viral genome replication and pathogenesis have not yet been elucidated. NS4B of the GPE-  vaccine strain and of the highly virulent Eystrup strain differ by a total of seven amino acid residues, two of which are located in the predicted trans-membrane domains of NS4B and were described previously to relate to virulence, and five residues clustering in the N-terminal part. In the present study, we examined the potential role of these five amino acids in modulating genome replication and determining pathogenicity in pigs. A chimeric low virulent GPE- -derived virus carrying the complete Eystrup NS4B showed enhanced pathogenicity in pigs. The in vitro replication efficiency of the NS4B chimeric GPE-  replicon was significantly higher than that of the replicon carrying only the two Eystrup-specific amino acids in NS4B. In silico and in vitro data suggest that the N-terminal part of NS4B forms an amphipathic α-helix structure. The N-terminal NS4B with these five amino acid residues is associated with the intracellular membranes. Taken together, this is the first gain-of-function study showing that the N-terminal domain of NS4B can determine CSFV genome replication in cell culture and viral pathogenicity in pigs.

Long-Lasting Fever and Lymphadenitis: Think about F. tularensis

We report the case of glandular tularemia that developed in a man supposedly infected by a tick bite in Western Switzerland. Francisella tularensis (F. tularensis) was identified. In Europe tularemia most commonly manifests itself as ulcero-glandular or glandular disease; the diagnosis of tularemia may be delayed in glandular form where skin or mucous lesion is absent, particularly in areas which are assumed to have a low incidence of the disease.

The influence of different fever definitions on the rate of fever in neutropenia diagnosed in children with cancer

BACKGROUND The temperature limit defining fever (TLDF) is based on scarce evidence. This study aimed to determine the rate of fever in neutropenia (FN) episodes additionally diagnosed by lower versus standard TLDF. METHODS In a single center using a high TLDF (39.0°C tympanic temperature, LimitStandard), pediatric patients treated with chemotherapy for cancer were observed prospectively. Results of all temperature measurements and CBCs were recorded. The application of lower TLDFs (LimitLow; range, 37.5°C to 38.9°C) versus LimitStandard was simulated in silicon, resulting in three types of FN: simultaneous FN, diagnosed at both limits within 1 hour; earlier FN, diagnosed >1hour earlier at LimitLow; and additional FN, not diagnosed at LimitStandard. RESULTS In 39 patients, 8896 temperature measurements and 1873 CBCs were recorded during 289 months of chemotherapy. Virtually applying LimitStandard resulted in 34 FN diagnoses. The predefined relevantly (≥15%) increased FN rate was reached at LimitLow 38.4°C, with total 44 FN, 23 simultaneous, 11 earlier, and 10 additional (Poisson rate ratioAdditional/Standard, 0.29; 95% lower confidence bound, 0.16). Virtually applying 37.5°C as LimitLow led to earlier FN diagnosis (median, 4.5 hours; 95% CI, 1.0 to 20.8), and to 53 additional FN diagnosed. In 51 (96%) of them, spontaneous defervescence without specific therapy was observed in reality. CONCLUSION Lower TLDFs led to many additional FN diagnoses, implying overtreatment because spontaneous defervescence was observed in the vast majority. Lower TLDFs led as well to relevantly earlier diagnosis in a minority of FN episodes. The question if the high TLDF is not only efficacious but as well safe remains open.

Management of fever and neutropenia in paediatric cancer patients: room for improvement?

PURPOSE OF REVIEW Fever and neutropenia is the most common complication in the treatment of childhood cancer. This review will summarize recent publications that focus on improving the management of this condition as well as those that seek to optimize translational research efforts. RECENT FINDINGS A number of clinical decision rules are available to assist in the identification of low-risk fever and neutropenia however few have undergone external validation and formal impact analysis. Emerging evidence suggests acute fever and neutropenia management strategies should include time to antibiotic recommendations, and quality improvement initiatives have focused on eliminating barriers to early antibiotic administration. Despite reported increases in antimicrobial resistance, few studies have focused on the prediction, prevention, and optimal treatment of these infections and the effect on risk stratification remains unknown. A consensus guideline for paediatric fever and neutropenia research is now available and may help reduce some of the heterogeneity between studies that have previously limited the translation of evidence into clinical practice. SUMMARY Risk stratification is recommended for children with cancer and fever and neutropenia. Further research is required to quantify the overall impact of this approach and to refine exactly which children will benefit from early antibiotic administration as well as modifications to empiric regimens to cover antibiotic-resistant organisms.

Core outcomes and definitions for pediatric fever and neutropenia research: a consensus statement from an international panel.

BACKGROUND There are no specific recommendations for the design and reporting of studies of children with fever and neutropenia (FN). As a result, there is marked heterogeneity in the variables and outcomes that are reported and new definitions continue to emerge. These inconsistencies hinder the ability of researchers and clinicians to compare, contrast and combine results. The objective was to achieve expert consensus on a core set of variables and outcomes that should be measured and reported, as a minimum, in pediatric FN studies. PROCEDURE The Delphi method was used to achieve consensus among an international group of clinicians, pharmacists, researchers, and patient representatives. Four surveys focusing on (i) the identification of a core set of variables and outcomes; and (ii) definitions of these variables and outcomes, were administered electronically. Consensus was predefined as more than 80% agreement on any statement. RESULTS There were forty-five survey participants and the response rate ranged between 84 and 96%. There was consensus on eight core variables and 10 core outcomes that should be collected and reported in all studies of children with FN. Consensus definitions were identified for all of the core outcomes. CONCLUSION Using the Delphi method, expert consensus on a set of core variables and outcomes, and their corresponding definitions, was achieved. These core sets represent the minimum that should be collected and reported in all studies of children with FN. This will promote collaboration and ensure consistency and comparability between studies.