Gernot Walder

Dr. Gernot Walder GmbH

Background Immune imprinting is a phenomenon in which a person's immune system develops a specific immunological memory of the pathogen or vaccine due to a previous exposure. This memory basically leads to a faster and stronger immune response in a subsequent contact to the same pathogen or vaccine. However, what happens if the pathogen has changed...

Background Residents of nursing homes are one of the most vulnerable groups during the severe acute syndrome coronavirus 2 (SARS-CoV-2) pandemic. The aim of this study was to characterize cellular and humoral immune responses in >70-year-old participants before vaccination, after first and second vaccination with BNT162b2, in contrast to second-dos...

Different scenarios explaining the emergence of novel variants of concern (VOC) of the Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been reported, including their evolution in scarcely monitored populations, in animals as alternative hosts, or in immunocompromised individuals. Here we report SARS-CoV-2 immune escape mutations o...

Knowledge of the level and duration of protective immunity against SARS‐CoV‐2 after primary infection is of crucial importance for preventive approaches. Currently, there is a lack of evidence on the persistence of specific antibodies. We investigated the generation and maintenance of neutralizing antibodies of convalescent SARS‐CoV‐2‐afflicted pat...

Since its outbreak in 2019, Severe Acute Respiratory Syndrome Coronavirus 2 keeps surprising the medical community by evolving diverse immune escape mutations in a rapid and effective manner. To gain deeper insight into mutation frequency and dynamics, we isolated ten ancestral strains of SARS-CoV-2 and performed consecutive serial incubation in te...

We studied a unique case of prolonged viral shedding in an immunocompromised patient that generated a series of SARS-CoV-2 immune escape mutations over a period of seven months. During the persisting SARS-CoV-2 infection seventeen non-synonymous mutations were observed, thirteen (13/17; 76.5%) of which occurred in the genomic region coding for spik...

Background and purpose COVID-19 is a novel viral disease causing worldwide pandemia. The aim of this study was describe the effect of adjunctive individualized homeopathic treatment delivered to hospitalized patients with confirmed symptomatic SARS-CoV-2 infection. Patient presentation Thirteen patients with COVID-19 were admitted. Mean age was 73...

Background At the beginning of the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), little was known about its actual rate of infectivity and any COVID-19 patient positive in laboratory testing was supposed to be highly infective and a public health risk factor. Methods One hundred oropharyngeal samples were obtaine...

Abstract Background At the beginning of the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), little was known about its actual rate of infectivity and any COVID-19 patient positive in laboratory testing was supposed to be highly infective and a public health risk factor. Methods One hundred oropharyngeal samples were...

CD8 ⁺ T cell immunity to SARS-CoV-2 has been implicated in COVID-19 severity and virus control. Here, we identified nonsynonymous mutations in MHC-I-restricted CD8 ⁺ T cell epitopes after deep sequencing of 747 SARS-CoV-2 virus isolates. Mutant peptides exhibited diminished or abrogated MHC-I binding in a cell-free in vitro assay. Reduced MHC-I bin...

A cohort of the first 50 COVID-19 patients in East Tyrol, a region in the southwest of Austria, were monitored in home quarantine. Specific viral ribonucleic acid was detected in throat swabs and stool samples. Analysis indicated a median virus shedding duration of 13 days; however, statistical outliers highlight the importance of consequent testin...

CD8+ T cell immunity to SARS-CoV-2 has been implicated in COVID-19 severity and virus control, though direct evidence has been lacking so far. Here, we identified non-synonymous mutations in MHC-I restricted CD8+ T cell epitopes after deep sequencing of 747 SARS-CoV-2 virus isolates. Mutant peptides exhibited diminished or abrogated MHC-I binding,...

Level and duration of protective immunity against SARS-CoV-2 after primary infection is of crucial importance for preventive approaches. In order to provide evidence for the longevity of specific antibodies, we investigated the generation and maintenance of neutralizing antibodies of convalescent SARS-CoV-2-afflicted patients over a five month peri...

Smell and taste disorders are acknowledged as characteristic symptoms for SARS-CoV-2 infection by now. These symptoms have been linked to a neuroinvasive course of disease. In this study, we investigated five consecutive COVID-19 patients with a prolonged course of dysosmia and dysgeusia. Those with objectifiable alteration in taste or smell were s...

Mosquitoes are of major importance to human and animal health due to their ability to transmit various pathogens. In Europe the role of mosquitoes in public health has increased with the introduction of alien Aedes mosquitoes such as the Asian tiger mosquito, Aedes albopictus; the Asian bush mosquito, Ae. japonicus; and Ae. koreicus. In Austria, Ae...

Systematic, continuous mosquito surveillance is considered the most reliable tool to predict the spread and establishment of alien mosquito species such as the Asian tiger mosquito (Aedes albopictus), Japanese bush mosquito (Aedes japonicus), and the transmission risk of mosquito-borne arboviruses to humans. Only single individuals of Ae. albopictu...

In this series of review articles entitled "Practical guidelines for studies on sandfly-borne phleboviruses,' the important points to be considered at the prefieldwork stage were addressed in part I, including parameters to be taken into account to define the geographic area for sand fly trapping and how to organize field collections. Here in part...

The purpose of this review is to provide practical information to help researchers intending to perform 'from field to laboratory' studies on phleboviruses transmitted by sandflies. This guideline addresses the different steps to be considered starting from the field collection of sandflies to the laboratory techniques aiming at the detection, isol...

The genera Babesia and Theileria (phylum Apicomplexa, order Piroplasmida) are mainly transmitted by Ixodid ticks in which the sexual part of their life cycle followed by sporogony takes place. They include protozoan parasites that infect erythrocytes of a variety of vertebrate hosts, including domestic and wild animals, with some Babesia spp. also...

The genus Anaplasma (Rickettsiales: Anaplasmataceae) comprises obligate intracellular Gram-negative bacteria that are mainly transmitted by ticks, and currently includes six species: Anaplasma bovis, Anaplasma centrale, Anaplasma marginale, Anaplasma phagocytophilum, Anaplasma platys, and Anaplasma ovis. These have long been known as etiological ag...

The obligate intracellular bacterium Chlamydia abortus is the causative agent of enzootic abortion of ewes (EAE) and poses a significant zoonotic risk for pregnant women. Using proteomic analysis and gene expression library screening in a previous project, we identified potential virulence factors and candidates for serodiagnosis, of which nine hav...

MultiLocus sequence typing (MLST) is considered a powerful method to unveil relationships within bacterial populations and it constitutes an economical and fast alternative to whole genome sequencing. We used this method to understand whether there are differences in human pathogenicity within and between different Borrelia burgdorferi sensu lato s...

A large majority of Austrian citizens are aware of tick-borne encephalitis (TBE), consequently reflected by a high vaccination rate of 85%. In return, risk assessment and disease mapping on human cases might be hampered due to high and inhomogeneous vaccination rates and travel habitats of humans. The roe deer was used to obtain a starting point fo...

Seroprevalences were determined by testing sera of 1607 blood donors from North, East, and South Tyrol. In the Tyrols, the continental divide delimitates areas with high seroprevalences of IgG antibodies against Borrelia burgdorferi sensu lato in the North (7.2%) from areas with low seroprevalences in the South (1.5%). To determine Borrelia prevale...

MultiLocus sequence typing (MLST) is considered a powerful method to unveil relationships within bacterial populations and it constitutes an economical and fast alternative to whole genome sequencing. We used this method to understand whether there are differences in human pathogenicity within and between different Borrelia burgdorferi sensu lato s...

Candidatus Neoehrlichia mikurensis is a newly emerging tick-borne bacterium from the family Anaplasmataceae. Its presence in Ixodes ricinus ticks was reported from various European countries, however, it's ecology and co-circulation with another member of the same family, Anaplasma phagocytophilum has not been rigorously studied yet. Candidatus N....

Abstract Seroprevalence rates for immunoglobulin G (IgG) antibodies to Tahyna virus (TAHV) and Inkoo virus (INKV) were determined in sera of 1630 blood donors from North, East, and South Tyrol by immunofluorescence assays (IFAs) and confirmatory serum neutralization tests (SNTs). Ten sera (0.6%) reacted positive by TAHV IFA, five of which (0.3%) we...

After malaria, babesiosis is the second most common transfusion-transmitted vector-borne disease. This study investigates seroprevalence rates to Babesia divergens and B. microti in the Tyrol and assesses the risk of blood products being contaminated by either agent. The area of investigation comprises the Austrian part of Tyrol. A number of 988 se...

After malaria, babesiosis is the second most common transfusion-transmitted parasitic disease in the United States. In Europe, one reported transfusion case, concerning Babesia microti, occurred in Germany. Due to the fact that Babesia spp. are present in Tyrolean ticks, the aim of this study is to assess the occurrence of immunoglobulin (Ig)G anti...

Enzootic abortion of ewes (EAE) due to infection with the obligate intracellular pathogen Chlamydia (C.) abortus is an important zoonosis leading to considerable economic loss to agriculture worldwide. The pathogen can be transmitted to humans and may lead to serious infection in pregnant women. Knowledge about epidemiology, clinical course and tra...

The aim of our study was to assess the occurrence of Rickettsia in the inner-alpine valleys of the Eastern Alps and to determine the amount of seroreaction among the local human population. Ticks were investigated by PCR and the percentage of seropositives was determined among local blood donors by an in-house immunofluorescence assay. The local cu...

In the last several years, West Nile virus (WNV) was proven to be present especially in the neighboring countries of Austria, such as Italy, Hungary, and the Czech Republic, as well as in eastern parts of Austria, where it was detected in migratory and domestic birds. In summer 2010, infections with WNV were reported from Romania and northern Greec...

Lyme neuroborreliosis (LNB) is the second most common manifestation of Borrelia burgdorferi sensu lato (s. l.) infection in Europe. LNB is difficult to differentiate from other aetiologies of aseptic meningitis. Diagnostic criteria for LNB in children are not established. Therfore, based on the epidemiology of LNB in children from Tyrol, the aim of...

All cases of tick-borne encephalitis (TBE), which were recorded in the Tyrol (Austria) between 2000 and 2006, were investigated, in order to detect changes in incidence and endemicity, to identify particular risk groups, and to evaluate the indication for vaccination. Patients, who presented with an acute febrile illness, positive anti-TBE IgM and/...

In order to analyze the clinical impact of immunological alterations in thymectomized children after exposure to a new antigen (tick-borne encephalitis virus (TBEV) vaccine), 17 thymectomized children completed a three-dose immunization regimen. Thymectomized children showed significantly lower TBEV IgG antibody levels after the second vaccination...

The aim of this study is to describe a case of fulminant myocarditis caused by co-infection with Chlamydophila pneumoniae and Chlamydophila psittaci in order to facilitate diagnosis and clinical management of patients suffering from this rare but life-threatening condition. Case report. Intensive care unit of Innsbruck Medical University. A 24-yr-o...

In a case-control study that included a total of 98 patients and 83 controls, the possible link between various pathogens and abdominal aortic aneurysms was investigated. For 68 patients with abdominal aortic aneurysm and age-matched controls, no differences were detected in the levels of immunoglobulin (Ig)A and IgG Chlamydiaceae and Chlamydophila...

We report five consecutive cases of Anaplasma (A.) phagocytophilum infection (the causative agent of human granulocytic anaplasmosis (HGA)) from western Austria. All infections were acquired between June and August in 2003 and 2004 in the Inn valley (Tyrol, Austria). Four patients required hospitalisation, one patient was treated as an outpatient....

Five hundred and forty-five serum samples from donors from various parts of Mongolia were investigated for antibodies against the tick-borne encephalitis (TBE) virus, Borrelia burgdorferi, and Anaplasma phagocytophilum. Seroprevalence against TBE was 5.1% in the province of Selenge and 0.9% in Bulgan province, seroprevalence against B. burgdorferi...

In order to expand current knowledge of the types of methicillin-resistant Staphylococcus aureus (MRSA) strains circulating in central Asia, six MRSA strains collected from hospitals in Ulaanbaatar, Mongolia during 2000-2002 were examined. Three strains possessed a staphylococcal cassette chromosome mec (SCCmec) element of type IV c, were sequence...

Chlamydophila abortus (formerly Chlamydia psittaci serovar 1) is a rare but severe cause of gestational septicemia, with particular problems in diagnosis and clinical management. A 32-year-old woman in her fourth pregnancy (16th week of gestation) presented with progressive septicemia after extensive contact with abortive material from her goat flo...

Stably transfected Chinese hamster ovary (CHO24S) cells were the source for Rubella virus-like particles (RVLP) containing all structural proteins (E1, E2, C and their dimers). RVLP are secreted from the CHO24S cells into the medium and the time-point for collecting the medium with the highest yield of >100 kDa proteins (with 17 mg protein from 10...

In order to ascertain the epidemiology of rubella infections in Austria, a seroepidemiological study was performed. Data collected from 115 cases diagnosed at the Institute of Hygiene and Social Medicine of the University of Innsbruck during 2001 were evaluated. The results indicate this infection can no longer be categorised as a paediatric diseas...

One hundred and fifty-one human sera from patients exposed to rubella virus (RV) and shown to be negative for IgM antibodies were tested for total RV-IgG, hemagglutination inhibition (HAI) and for virus neutralizing (VN) antibodies using a peptide enzyme-linked immunosorbent assay (ELISA) based on BCH-178, a peptide representing one of several know...

We report the first documented case of an extragestational infection with Chlamydophila abortus in humans. The pathogen was identified in a patient with severe pelvic inflammatory disease (PID) by sequence analysis of the ompA gene. Our findings raise the possibility that Chlamydiaceae other than Chlamydia trachomatis are involved in PID.

In order to evaluate the seroprevalence of human granulocytic ehrlichiosis in western Austria, sera from 357 Tyrolean blood donors were tested by an immunofluorescence assay. To assess the concomitant seroreactivity against Borrelia burgdorferi sensu lato, sera were further investigated by enzyme-linked immunoassay and Western blot. Thirty-two sera...

We report the first documented case of human granulocytic ehrlichiosis (HGE) in Austria. The infection was acquired near Arzl in the surroundings of Innsbruck in northern Tyrol. Except for a biphasic course of illness, presentation in this 33-year-old female patient was comparable to clinical findings observed in other European adults with high fev...

This study reports an extraordinarily severe and prolonged course of neuroornithosis with generalized status epilepticus as an initial symptom. Direct invasion of the central nervous system by Chlamydophila psittaci was confirmed by the demonstration of specific DNA in the patient's cerebrospinal fluid. The patient recovered slowly under administra...

The elimination of BTEX (benzene, toluene, ethylbenzene, o-xylene) compounds from soil was studied. After 18 days at 20 °C, 21% of the initial total BTEX contamination (400 mg/kg soil) was lost due to sorption onto soil. Biodegradation decreased in the order ethylbenzene > toluene > benzene > o-xylene. NPK fertilisation stimulated biodegradation, p...

The present study provides evidence and documentation of the first case of infection with the tick-borne encephalitis (TBE) virus acquired in the federal state of Vorarlberg (Austria). The area in which the viral infection was discovered lies in the vicinity of Ludesch in the Illvalley (Bludenz district). In order to investigate the current state o...

The impact of hydrocarbon remediation on several enzyme activities (catalase, dehydrogenase, lipase, protease, urease, alkaline phosphomonoesterase, fluorescein diacetate hydrolysis) and microbial properties (biomass-C, respiration, N-mineralization, qCO2, microbial counts) was evaluated in a laboratory study over a period of 10 weeks. A pristine s...

The action resonance theory (ART), a hypothesis based on a logical extension of EINSTEIN'S theory of Brownian movement, suggests that the genotype x environment interaction can be modelled as forceful encounters of the gene-products of an organism with its environment. This model has implications for molecular and cell biology, morphogenesis, evolu...