Barbara Willi

Dr. Barbara Willi

orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 December 2007 in Veterinary Microbiology
Verified
Journal Article
Closed access
BWBarbara Willi
Barbara Willi
FBFelicitas S. Boretti
Felicitas S. Boretti
Séverine TaskerSéverine Tasker
Séverine Tasker
MMMarina L. Meli
Marina L. Meli
NWNicole Wengi
Nicole Wengi
Regina Hofmann-LehmannRegina Hofmann-Lehmann
Regina Hofmann-Lehmann

13 November 2015 in BMC Veterinary Research
Verified
Journal Article
Open access
PDF file
ABAlice Berger
Alice Berger
BWBarbara Willi
Barbara Willi
MMMarina L. Meli
Marina L. Meli
FBFelicitas S. Boretti
Felicitas S. Boretti
SHSonja Hartnack
Sonja Hartnack
Regina Hofmann-LehmannRegina Hofmann-Lehmann
Regina Hofmann-Lehmann
Cats with feline calicivirus (FCV)-related symptoms are commonly presented to veterinary practitioners. Various clinical manifestations have been attributed to FCV, i.e. upper respiratory tract disease (URTD), oral ulcerations, gingivostomatitis, limping syndrome and virulent systemic disease. Additionally, healthy cats can shed FCV. The aims of this study were 1) to investigate the frequency of FCV in cats with FCV-related symptoms and in healthy cats in Switzerland, 2) to assess risk and protective factors for infection, such as signalment, housing conditions, vaccination, and co-infection with URTD-associated pathogens, and 3) to address the association between clinical symptoms and FCV infection. Oropharyngeal, nasal and conjunctival swabs were collected in 24 veterinary practices from 200 FCV-suspect and 100 healthy cats originating from 19 cantons of Switzerland. The samples were tested for FCV using virus isolation and reverse-transcription real-time quantitative polymerase chain reaction (qPCR) and for feline herpesvirus-1 (FHV-1), Mycoplasma felis, Chlamydophila felis, Bordetella bronchiseptica using real-time qPCR. Within the two populations (FCV-suspect/healthy), the observed PCR prevalences were: FCV 45 %/8 %, FHV-1 20 %/9 %, C. felis 8 %/1 %, B. bronchiseptica 4 %/2 %, M. felis 47 %/31 % and any co-infections thereof 40 %/14 %. Based on multivariable regression models amongst FCV-suspect cats (odds ratio [95 % confidence interval]), co-infection with M. felis (1.75 [0.97; 3.14]), group housing (2.11 [1.02; 4.34]) and intact reproductive status (1.80 [0.99; 3.28]) were found to be risk factors for FCV infection. In healthy cats, intact reproductive status (22.2 [1.85; 266.7]) and group housing (46.4 [5.70; 377.7]) were found to be associated with FCV infection. Based on an univariable approach, FCV-suspect cats were found to be significantly less often FCV-positive when vaccinated (0.48 [0.24; 0.94]). Oral ulcerations, salivation, gingivitis and stomatitis, but not classical signs of URTD were significantly associated with FCV infection (all p < 0.001). FCV was detected in less than half of the cats that were judged FCV-suspect by veterinary practitioners. For a clinical diagnosis, FCV-related symptoms should be revisited. FCV infection was present in some healthy cats, underlining the importance of asymptomatic carriers in FCV epidemiology. To reduce FCV-related problems in multi-cat environments, reduction of group size in addition to the generally recommended vaccination are advocated.

17 March 2021 in Viruses
Verified
Journal Article
Open access
PDF file
JKJulia Klaus
Julia Klaus
MMMarina L. Meli
Marina L. Meli
BWBarbara Willi
Barbara Willi
SNSarah Nadeau
Sarah Nadeau
CBChristian Beisel
Christian Beisel
Regina Hofmann-LehmannRegina Hofmann-Lehmann
Regina Hofmann-Lehmann
Since the emergence of coronavirus disease (COVID-19) in late 2019, domestic cats have been demonstrated to be susceptible to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) under natural and experimental conditions. As pet cats often live in very close contact with their owners, it is essential to investigate SARS-CoV-2 infections in cats in a One-Health context. This study reports the first SARS-CoV-2 infection in a cat in a COVID-19-affected household in Switzerland. The cat (Cat 1) demonstrated signs of an upper respiratory tract infection, including sneezing, inappetence, and apathy, while the cohabiting cat (Cat 2) remained asymptomatic. Nasal, oral, fecal, fur, and environmental swab samples were collected twice from both cats and analyzed by RT-qPCR for the presence of SARS-CoV-2 viral RNA. Both nasal swabs from Cat 1 tested positive. In addition, the first oral swab from Cat 2 and fur and bedding swabs from both cats were RT-qPCR positive. The fecal swabs tested negative. The infection of Cat 1 was confirmed by positive SARS-CoV-2 S1 receptor binding domain (RBD) antibody testing and neutralizing activity in a surrogate assay. The viral genome sequence from Cat 1, obtained by next generation sequencing, showed the closest relation to a human sequence from the B.1.1.39 lineage, with one single nucleotide polymorphism (SNP) difference. This study demonstrates not only SARS-CoV-2 infection of a cat from a COVID-19-affected household but also contamination of the cats’ fur and bed with viral RNA. Our results are important to create awareness that SARS-CoV-2 infected people should observe hygienic measures to avoid infection and contamination of animal cohabitants.

23 June 2020 in Antimicrobial Resistance & Infection Control
Verified
Journal Article
Open access
PDF file
JSJanne S. Schmidt
Janne S. Schmidt
SKStefan P. Kuster
Stefan P. Kuster
ANAurélien Nigg
Aurélien Nigg
VDValentina Dazio
Valentina Dazio
MBMichael Brilhante
Michael Brilhante
BWBarbara Willi
Barbara Willi
Background: Intensive medical care in companion animal clinics could pose a risk for the selection and dissemination of multidrug-resistant organisms (MDROs). Infection prevention and control (IPC) concepts are key measures to reduce the spread of MDROs, but data on IPC standards in companion animal clinics is sparse. The study assessed IPC standards in seven companion animal clinics and practices in Switzerland by structured IPC audits and combined results with environmental MDRO contamination and MDRO carriage of the personnel.Methods: IPC audits were held between August 2018 and January 2019. The observations in 34 IPC areas were scored based on predefined criteria (not fulfilled/partially fulfilled/fulfilled = score 0/1/2). Environmental swabs and nasal and stool samples from veterinary personnel were tested for methicillin-resistant (MR) staphylococci and macrococci and for colistin-resistant, extended-spectrum β-lactamase- and carbapenemase-producing (CP)Enterobacterales(CPE). Species was identified by MALDI-TOF MS, antimicrobial resistance determined by microdilution and β-lactam resistance gene detection, and genetic relatedness assessed by REP−/ERIC-PCR and multilocus sequence typing.Results: Of a maximum total IPC score of 68, the institutions reached a median (range) score of 33 (19–55). MDROs were detected in median (range) 8.2% (0–33.3%) of the sampling sites. Clinics with low IPC standards showed extensive environmental contamination, i.e. of intensive care units, consultation rooms and utensils. CPE were detected in two clinics; one of them showed extensive contamination with CPKlebsiella pneumoniae(ST11,blaOXA-48) and MRStaphylococcus pseudintermedius(ST551,mecA). Despite low IPC scores, environmental contamination with MDROs was low in primary opinion practices. Three employees were colonized withEscherichia coliST131 (blaCTX-M-15,blaCTX-M-27,blaCTX-M-14). Two employees carried CPE. coliclosely related to environmental (ST410,blaOXA-181) and patient-derived isolates (ST167,blaNDM-5). MRStaphylococcus aureus(ST225,mecA) and MRS. pseudintermedius(ST551,mecA) of the same sequence types and with similar resistance profiles were found in employees and the environment in two clinics.Conclusions: The study indicates that IPC standards in companion animal clinics are variable and that insufficient IPC standards could contribute to the evolution of MDROs which can be transferred between the environment and working personnel. The implementation of IPC concepts in companion animal clinics should urgently be promoted.

21 December 2015 in Retrovirology
Verified
Journal Article
Open access
PDF file
SNStefanie Nesina
Stefanie Nesina
A(A. Katrin Helfer (-Hungerbuehler)
A. Katrin Helfer (-Hungerbuehler)
Barbara RiondBarbara Riond
Barbara Riond
FBFelicitas S. Boretti
Felicitas S. Boretti
BWBarbara Willi
Barbara Willi
Regina Hofmann-LehmannRegina Hofmann-Lehmann
Regina Hofmann-Lehmann
The feline leukemia virus (FeLV) is a gamma-retrovirus of domestic cats that was discovered half a century ago. Cats that are infected with FeLV may develop a progressive infection resulting in persistent viremia, immunodeficiency, tumors, anemia and death. A significant number of cats mount a protective immune response that suppresses viremia; these cats develop a regressive infection characterized by the absence of viral replication and the presence of low levels of proviral DNA. The biological importance of these latter provirus carriers is largely unknown. Here, we demonstrate that ten cats that received a transfusion of blood from aviremic provirus carriers developed active FeLV infections, some with a progressive outcome and the development of fatal FeLV-associated disease. The infection outcome, disease spectrum and evolution into FeLV-C in one cat mirrored those of natural infection. Two cats developed persistent antigenemia; six cats were transiently antigenemic. Reactivation of infection occurred in some cats. One recipient developed non-regenerative anemia associated with FeLV-C, and four others developed a T-cell lymphoma, one with secondary lymphoblastic leukemia. Five of the ten recipient cats received provirus-positive aviremic blood, whereas the other five received provirus- and viral RNA-positive but aviremic blood. Notably, the cats that received blood containing only proviral DNA exhibited a later onset but graver outcome of FeLV infection than the cats that were transfused with blood containing proviral DNA and viral RNA. Leukocyte counts and cytokine analyses indicated that the immune system of the latter cats reacted quicker and more efficiently. Our results underline the biological and epidemiological relevance of FeLV provirus carriers and the risk of inadvertent FeLV transmission via blood transfusion and demonstrate the replication capacity of proviral DNA if uncontrolled by the immune system. Our results have implications not only for veterinary medicine, such as the requirement for testing blood donors and blood products for FeLV provirus by sensitive polymerase chain reaction, but are also of general interest by revealing the importance of latent retroviral DNA in infected hosts. When aiming to eliminate a retroviral infection from a population, provirus carriers must be considered.

9 February 2021 in Antibiotics
Verified
Journal Article
Open access
PDF file
Kira SchmittKira Schmitt
Kira Schmitt
SKStefan P. Kuster
Stefan P. Kuster
KZKatrin Zurfluh
Katrin Zurfluh
RJRahel S. Jud
Rahel S. Jud
Jane SykesJane Sykes
Jane Sykes
BWBarbara Willi
Barbara Willi
Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) among animals and humans are a public health threat. This study analyzed the occurrence of ESBL-E in a high-risk environment in a companion animal clinic and two animal patients’ households. In an intensive care unit (ICU), rectal swabs from 74 dogs and cats, 74 hand swabs from staff and 298 swabs from surfaces were analyzed for ESBL-E. Seventeen hospitalized patients (23%) and ten (3%) surfaces in the ICU tested ESBL-E positive. Transmission chains for Klebsiella pneumoniae ST307 blaCTX-M-15 and Escherichia coli ST38 blaCTX-M-14, ST88 blaCTX-M-14 and ST224 blaCTX-M-1 were observed over extended periods of time (14 to 30 days) with similar strains isolated from patients and the clinical environment. After discharge, two colonized dogs (dogs 7 and 12) and their household contacts were resampled. Dog 7 tested repeatedly positive for 77 days, dog 12 tested negative; six (24%) surfaces in the household of the persistently colonized dog tested ESBL-E positive. The owner of dog 7 and one of the owners of dog 12 were colonized. Based on whole genome sequencing, isolates from the owners, their dogs and other ICU patients belonged to the same clusters, highlighting the public health importance of ESBL-E in companion animal clinics.