Alpha-1-Acid Glycoprotein Quantification via Spatial Proximity Analyte Reagent Capture Luminescence Assay: Application as Diagnostic and Prognostic Marker in Serum and Effusions of Cats with Feline Infectious Peritonitis Undergoing GS-441524 Therapy

Until recently, the diagnosis of feline infectious peritonitis (FIP) in cats usually led to euthanasia, but recent research has revealed that antiviral drugs, including the nucleoside analog GS-441524, have the potential to effectively cure FIP. Alpha-1-acid glycoprotein (AGP) has been suggested as a diagnostic marker for FIP. However, AGP quantification methods are not easily accessible. This study aimed to establish a Spatial Proximity Analyte Reagent Capture Luminescence (SPARCLTM) assay on the VetBio-1 analyzer to determine the AGP concentrations in feline serum and effusion samples. Linearity was found in serial dilutions between 1:2000 and 1:32,000; the intra-run and inter-run precision was <5% and <15%, respectively; and AGP was stable in serum stored for at least 8 days at room temperature, at 4 °C and at -20 °C. Cats with confirmed FIP had significantly higher serum AGP concentrations (median: 2954 µg/mL (range: 200-5861 µg/mL)) than those with other inflammatory diseases (median: 1734 µg/mL (305-3449 µg/mL)) and clinically healthy cats (median 235 µg/mL (range: 78-616 µg/mL); pKW < 0.0001). The AGP concentrations were significantly higher in the effusions from cats with FIP than in those from diseased cats without FIP (pMWU < 0.0001). The AGP concentrations in the serum of cats with FIP undergoing GS-441524 treatment showed a significant drop within the first seven days of treatment and reached normal levels after ~14 days. In conclusion, the VetBio-1 SPARCLTM assay offers a precise, fast and cost-effective method to measure the AGP concentrations in serum and effusion samples of feline patients. The monitoring of the AGP concentration throughout FIP treatment provides a valuable marker to evaluate the treatment's effectiveness and identify potential relapses at an early stage.

Evaluation of a Revised Point-of-Care Test for the Detection of Feline Leukaemia p27 Antigen and Anti-p15E Antibodies in Cats

The first point-of-care (PoC) test (v-RetroFel®; modified version 2021) determining the presence of FeLV p27 antigen and FeLV anti-p15E antibodies has become recently commercially available to identify different feline leukaemia virus (FeLV) infection outcomes. This study aimed to assess this PoC test's performance concerning FeLV p27 antigen and FeLV anti-p15E antibody detection. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) were assessed after ten minutes (recommended) and 20 min (prolonged) incubation times. The test results were evaluated as either positive or negative. Serum samples from 934 cats were included, originating from Italy (n = 269), Portugal (n = 240), Germany (n = 318), and France (n = 107). FeLV p27 antigen and anti-p15E antibodies were measured by reference standard ELISAs and compared to the PoC test results. The PoC test was easy to perform and the results easy to interpret. Sensitivity and specificity for FeLV p27 antigen were 82.8% (PPV: 57.8%) and 96.0% (NPV: 98.8%) after both, ten and 20 minues of incubation time. Sensitivity and specificity for anti-p15E antibodies were 31.4% (PPV: 71.6%) and 96.9% (NPV: 85.1%) after ten minutes incubation time; sensitivity was improved by a prolonged incubation time (20 min) to 40.0% (PPV: 76.3%), while specificity remained the same (96.9%, NPV: 86.7%). Despite the improved sensitivity using the prolonged incubation time, lower than ideal sensitivities for both p27 antigen and especially anti-p15E antibodies were found, indicating that the PoC test in its current version needs further improvement prior to application in the field.

Detection of SARS-CoV-2 RNA in a Zoo-Kept Red Fox (Vulpes vulpes)

Many different animal species are susceptible to SARS-CoV-2, including a few Canidae (domestic dog and raccoon dog). So far, only experimental evidence is available concerning SARS-CoV-2 infections in red foxes (Vulpes vulpes). This is the first report of SARS-CoV-2 RNA detection in a sample from a red fox. The RT-qPCR-positive fox was zoo-kept together with another fox and two bears in the Swiss Canton of Zurich. Combined material from a conjunctival and nasal swab collected for canine distemper virus diagnostics tested positive for SARS-CoV-2 RNA with Ct values of 36.9 (E gene assay) and 35.7 (RdRp gene assay). The sample was analysed for SARS-CoV-2 within a research project testing residual routine diagnostic samples from different animal species submitted between spring 2020 and December 2022 to improve knowledge on SARS-CoV-2 infections within different animal species and investigate their potential role in a One Health context. Within this project, 246 samples from 153 different animals from Swiss zoos and other wild animal species all tested SARS-CoV-2 RT-qPCR and/or serologically negative so far, except for the reported fox. The source of SARS-CoV-2 in the fox is unknown. The fox disappeared within the naturally structured enclosure, and the cadaver was not found. No further control measures were undertaken.

Long-term surveillance of the feline leukemia virus in the endangered Iberian lynx (Lynx pardinus) in Andalusia, Spain (2008-2021)

Feline leukemia virus (FeLV) infection is considered one of the most serious disease threats for the endangered Iberian lynx (Lynx pardinus) Over 14 years (2008-2021), we investigated FeLV infection using point-of-care antigen test and quantitative real-time TaqMan qPCR for provirus detection in blood and tissues in lynxes from Andalusia (Southern Spain). A total of 776 samples from 586 individuals were included in this study. The overall prevalence for FeLV antigen in blood/serum samples was 1.4% (5/360) (95% CI: 0.2-2.6), FeLV proviral DNA prevalence in blood samples was 6.2% (31/503) (95% CI: 4.1-8.6), and FeLV proviral DNA in tissues samples was 10.2% (34/333) (95% CI: 7-13.5). From a subset of 129 longitudinally sampled individuals, 9.3% (12/129) PCR-converted during the study period. Our results suggest that FeLV infection in the Andalusian population is enzootic, with circulation of the virus at low levels in almost all the sampling years. Moreover, since only one viremic individual succumbed to the infection, this study suggests that lynxes may therefore control the infection decreasing the possibility of developing a more aggressive outcome. Although our results indicate that the FeLV infection in the Iberian lynx from Andalusia tends to stay within the regressive stage, continuous FeLV surveillance is paramount to predict potential outbreaks and ensure the survival of this population.

Prospective Investigation of Feline Leukemia Virus Infection in Stray Cats Subjected to a Trap-Neuter-Return Program in Switzerland

Feline leukemia virus (FeLV) remains a serious concern in some countries despite advances in diagnostics and vaccines. FeLV-infected cats often have reduced lifespans due to FeLV-associated diseases. The infection is transmitted through social interactions. While Northern European countries have reported a decrease in FeLV among pet cats, Switzerland's rates remain stagnant at 2.7% (2016/17: 95% CI 1.4-5.2%). Research on FeLV in Swiss stray cats has been lacking, even though these animals could serve as a virus reservoir. Sampling stray cats that do not receive regular veterinary care can be challenging. Collaboration with the Swiss Network for Animal Protection (NetAP) allowed for the prospective collection of saliva samples from 1711 stray cats during a trap-neuter-return program from 2019 to 2023. These samples were tested for FeLV RNA using RT-qPCR as a measure for antigenemia. Viral RNA was detected in 4.0% (95% CI 3.1-5.0%) of the samples, with 7.7% (95% CI 4.9-11.3%) in sick cats and 3.3% (95% CI 2.4-4.4%) in healthy ones. We identified three geographically independent hotspots with alarmingly high FeLV infection rates in stray cats (up to 70%). Overall, including the previous data of privately owned cats, FeLV-positive cats were scattered throughout Switzerland in 24/26 cantons. Our findings underscore welfare concerns for FeLV infections among stray cats lacking veterinary attention, highlighting the potential risk of infection to other free-roaming cats, including those privately owned. This emphasizes the critical significance of vaccinating all cats with outdoor access against FeLV and developing programs to protect cats from FeLV infections.

Serological and Molecular Investigation of SARS-CoV-2 in Horses and Cattle in Switzerland from 2020 to 2022

Horses and cattle have shown low susceptibility to SARS-CoV-2, and there is no evidence of experimental intraspecies transmission. Nonetheless, seropositive horses in the US and seropositive cattle in Germany and Italy have been reported. The current study investigated the prevalence of antibodies against SARS-CoV-2 in horses and cattle in Switzerland. In total, 1940 serum and plasma samples from 1110 horses and 830 cattle were screened with a species-specific ELISA based on the SARS-CoV-2 receptor-binding domain (RBD) and, in the case of suspect positive results, a surrogate virus neutralization test (sVNT) was used to demonstrate the neutralizing activity of the antibodies. Further confirmation of suspect positive samples was performed using either a pseudotype-based virus neutralization assay (PVNA; horses) or an indirect immunofluorescence test (IFA; cattle). The animals were sampled between February 2020 and December 2022. Additionally, in total, 486 bronchoalveolar lavage (BAL), oropharyngeal, nasal and rectal swab samples from horses and cattle were analyzed for the presence of SARS-CoV-2 RNA via reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Six horses (0.5%; 95% CI: 0.2-1.2%) were suspect positive via RBD-ELISA, and neutralizing antibodies were detected in two of them via confirmatory sVNT and PVNA tests. In the PVNA, the highest titers were measured against the Alpha and Delta SARS-CoV-2 variants. Fifteen cattle (1.8%; 95% CI: 1.0-3.0%) were suspect positive in RBD-ELISA; 3 of them had SARS-CoV-2-specific neutralizing antibodies in sVNT and 4 of the 15 were confirmed to be positive via IFA. All tested samples were RT-qPCR-negative. The results support the hypotheses that the prevalence of SARS-CoV-2 infections in horses and cattle in Switzerland was low up to the end of 2022.

Prevalence of Different Courses of Feline Leukaemia Virus Infection in Four European Countries

Prevalence of progressive feline leukaemia virus (FeLV) infection is known to still be high in cats in Europe, especially in Southern Europe, but the prevalence of other outcomes of FeLV infection has not been determined in most countries. The present study aimed to investigate the prevalence of progressive, regressive, abortive, and focal infection in four European countries, two with a high (Italy, Portugal) and two with a low expected prevalence (Germany, France). Blood samples of 934 cats (Italy: 269; Portugal: 240; France: 107; Germany: 318) were evaluated for the p27 antigen, as well as anti-whole virus, anti-SU, and anti-p15E antibodies by enzyme-linked immunosorbent assay (ELISA) in serum and for proviral DNA by quantitative polymerase chain reaction (qPCR) in whole blood. Positive p27 antigen ELISA results were confirmed by reverse transcriptase-qPCR (RT-qPCR) detecting viral RNA in saliva swabs and/or blood. The outcome of FeLV infection was categorised as progressive (antigen-positive, provirus-positive), regressive (antigen-negative, provirus-positive), abortive (antigen- and provirus-negative, antibody-positive), and focal (antigen-positive, provirus-negative) infection. Overall FeLV prevalence was 21.2% in Italy, 20.4% in Portugal, 9.5% in Germany, and 9.3% in France. Prevalence of progressive, regressive, abortive, and focal infection in Italy was 7.8%, 4.5%, 6.3%, and 2.6%; in Portugal 3.8%, 8.3%, 6.7%, and 1.7%; in Germany 1.9%, 1.3%, 3.5%, and 2.8%; in France 1.9%, 3.7%, 2.8%, and 0.9%, respectively. In conclusion, overall FeLV prevalence is still very high, especially in Southern European countries. Therefore, testing, separation of infected cats, and vaccination are still important measures to reduce the risk of FeLV infection.

Long-term follow-up of cats in complete remission after treatment of feline infectious peritonitis with oral GS-441524

OBJECTIVES

Feline infectious peritonitis (FIP), a common disease in cats caused by feline coronavirus (FCoV), is usually fatal once clinical signs appear. Successful treatment of FIP with oral GS-441524 for 84 days was demonstrated recently by this research group. The aim of this study was to evaluate the long-term outcome in these cats.

METHODS

A total of 18 successfully treated cats were followed for up to 1 year after treatment initiation (9 months after completion of the antiviral treatment). Follow-up examinations were performed at 12-week intervals, including physical examination, haematology, serum biochemistry, abdominal and thoracic ultrasound, FCoV ribonucleic acid (RNA) loads in blood and faeces by reverse transciptase-quantitative PCR and anti-FCoV antibody titres by indirect immunofluorescence assay.

RESULTS

Follow-up data were available from 18 cats in week 24, from 15 cats in week 36 and from 14 cats in week 48 (after the start of treatment), respectively. Laboratory parameters remained stable after the end of the treatment, with undetectable blood viral loads (in all but one cat on one occasion). Recurrence of faecal FCoV shedding was detected in five cats. In four cats, an intermediate short-term rise in anti-FCoV antibody titres was detected. In total, 12 cats showed abdominal lymphadenomegaly during the follow-up period; four of them continuously during the treatment and follow-up period. Two cats developed mild neurological signs, compatible with feline hyperaesthesia syndrome, in weeks 36 and 48, respectively; however, FCoV RNA remained undetectable in blood and faeces, and no increase in anti-FCoV antibody titres was observed in these two cats, and the signs resolved.

CONCLUSIONS AND RELEVANCE

Treatment with GS-441524 proved to be effective against FIP in both the short term as well as the long term, with no confirmed relapse during the 1-year follow-up period. Whether delayed neurological signs could be a long-term adverse effect of the treatment or associated with a 'long FIP syndrome' needs to be further evaluated.

A Risk Factor Analysis of SARS-CoV-2 Infection in Animals in COVID-19-Affected Households

A higher prevalence of SARS-CoV-2 infections in animals that have close contact with SARS-CoV-2-positive humans ("COVID-19 households") has been demonstrated in several countries. This prospective study aimed to determine the SARS-CoV-2 prevalence in animals from Swiss COVID-19 households and to assess the potential risk factors for infection. The study included 226 companion animals (172 cats, 76.1%; 49 dogs, 21.7%; and 5 other animals, 2.2%) from 122 COVID-19 households with 336 human household members (including 230 SARS-CoV-2-positive people). The animals were tested for viral RNA using an RT-qPCR and/or serologically for antibodies and neutralizing activity. Additionally, surface samples from animal fur and beds underwent an RT-qPCR. A questionnaire about hygiene, animal hygiene, and contact intensity was completed by the household members. A total of 49 of the 226 animals (21.7%) from 31 of the 122 households (25.4%) tested positive/questionably positive for SARS-CoV-2, including 37 of the 172 cats (21.5%) and 12 of the 49 dogs (24.5%). The surface samples tested positive significantly more often in households with SARS-CoV-2-positive animals than in households with SARS-CoV-2-negative animals (p = 0.011). Significantly more animals tested positive in the multivariable analysis for households with minors. For cats, a shorter length of outdoor access and a higher frequency of removing droppings from litterboxes were factors that were significantly associated with higher infection rates. The study emphasizes that the behavior of owners and the living conditions of animals can influence the likelihood of a SARS-CoV-2 infection in companion animals. Therefore, it is crucial to monitor the infection transmission and dynamics in animals, as well as to identify the possible risk factors for animals in infected households.

Field Performance of a Rapid Test to Detect Progressive, Regressive, and Abortive Feline Leukemia Virus Infections in Domestic Cats in Australia and Germany

Different feline leukemia virus (FeLV) infection outcomes are possible in cats following natural exposure, such as progressive infections (persistent viremia), regressive infections (transient or no viremia followed by proviral persistence) and abortive infections (presence of only antibodies). Laboratory-based testing is currently required for categorization of infection outcomes in cats. The aim of this study was to evaluate the field performance of a novel, rapid, combination point-of-care (PoC) test kit commercially available in Europe (v-RetroFel^®Ag/Ab; 2020-2021 version) to determine different FeLV infection outcomes by concurrent detection of FeLV antigen (p27) and antibodies against FeLV transmembrane envelope protein (p15E). A secondary aim was to evaluate the performance of the same test kit (v-RetroFel^®FIV) to determine positive/negative feline immunodeficiency virus (FIV) infection status by the detection of antibodies to FIV capsid protein (p24) and transmembrane glycoprotein (gp40). Two cohorts of domestic cats were recruited and tested with v-RetroFel^® using plasma or serum, including cats in Australia (n = 200) and cats in Germany (n = 170). Results from p27 antigen PoC testing, proviral DNA PCR, and neutralizing antibody testing or testing for antibodies against non-glycosylated surface unit envelope protein (p45) were used to assign cats to groups according to different FeLV infection outcomes. Testing with a laboratory-based FeLV p15E antibody ELISA was also performed for comparison. In the first cohort, v-RetroFel^®Ag/Ab correctly identified 89% (109/122) FeLV-unexposed cats and 91% (21/23) progressive infections, but no regressive (0/23) or abortive (0/32) infections. In the second cohort, v-RetroFel^®Ag/Ab correctly identified 94% (148/158) FeLV-unexposed cats and 100% (4/4) progressive infections, but no regressive (0/2) and only 17% (1/6) abortive infections. There was test agreement between v-RetroFel^®Ab and the p15E laboratory ELISA in 58.9% of samples. As a secondary outcome of this study, the sensitivity and specificity of v-RetroFel^®FIV testing in cohort 1 were 94.7% (18/19) and 98.3% (178/181), and in cohort 2, 30.0% (3/10) and 100.0% (160/160), respectively. Prior history of FIV vaccination did not produce any false-positive FIV results. In conclusion, v-RetroFel^®Ag/Ab (2020-2021 version) was unable to accurately determine different FeLV infection outcomes in the field. Improvements of the test prior to application to field samples are required.

Fatal gastritis and enterocolitis due to concurrent Helicobacter pylori and Campylobacter jejuni infection in a captive cheetah (Acinonyxjubatus)

A 3.5-year-old female cheetah (Acinonyx jubatus) died after a 10-day history of anorexia, regurgitation and diarrhoea despite symptomatic therapy. At gross post-mortem examination, the stomach was blood-filled with mucosal thickening and multifocal ulcerations. The intestinal mucosa was thickened and reddened, and the intestinal lumen was filled with dark red to black pasty content. Gastric histological lesions were compatible with gastritis due to Helicobacter infection, which was confirmed by polymerase chain reaction. Histology of the intestines revealed a severe necrotizing neutrophilic enterocolitis with abundant intralesional curved to spiral bacteria, corresponding to Campylobacter jejuni, which were subsequently isolated from both small and large intestinal contents. No other intestinal pathogens were detected despite thorough investigations. These findings suggest that C. jejuni may have played an aetiological role in the enterocolitis. Such an association has not been previously reported in non-domestic felids.

Detection and Molecular Characterization of the SARS-CoV-2 Delta Variant and the Specific Immune Response in Companion Animals in Switzerland

In human beings, there are five reported variants of concern of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). However, in contrast to human beings, descriptions of infections of animals with specific variants are still rare. The aim of this study is to systematically investigate SARS-CoV-2 infections in companion animals in close contact with SARS-CoV-2-positive owners ("COVID-19 households") with a focus on the Delta variant. Samples, obtained from companion animals and their owners were analyzed using a real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) and next-generation sequencing (NGS). Animals were also tested for antibodies and neutralizing activity against SARS-CoV-2. Eleven cats and three dogs in nine COVID-19-positive households were RT-qPCR and/or serologically positive for the SARS-CoV-2 Delta variant. For seven animals, the genetic sequence could be determined. The animals were infected by one of the pangolin lineages B.1.617.2, AY.4, AY.43 and AY.129 and between zero and three single-nucleotide polymorphisms (SNPs) were detected between the viral genomes of animals and their owners, indicating within-household transmission between animal and owner and in multi-pet households also between the animals. NGS data identified SNPs that occur at a higher frequency in the viral sequences of companion animals than in viral sequences of humans, as well as SNPs, which were exclusively found in the animals investigated in the current study and not in their owners. In conclusion, our study is the first to describe the SARS-CoV-2 Delta variant transmission to animals in Switzerland and provides the first-ever description of Delta-variant pangolin lineages AY.129 and AY.4 in animals. Our results reinforce the need of a One Health approach in the monitoring of SARS-CoV-2 in animals.

Clinical Follow-Up and Postmortem Findings in a Cat That Was Cured of Feline Infectious Peritonitis with an Oral Antiviral Drug Containing GS-441524

This is the first report on a clinical follow-up and postmortem examination of a cat that had been cured of feline infectious peritonitis (FIP) with ocular manifestation by successful treatment with an oral multicomponent drug containing GS-441524. The cat was 6 months old when clinical signs (recurrent fever, lethargy, lack of appetite, and fulminant anterior uveitis) appeared. FIP was diagnosed by ocular tissue immunohistochemistry after enucleation of the affected eye. The cat was a participant in a FIP treatment study, which was published recently. However, 240 days after leaving the clinic healthy, and 164 days after the end of the 84 days of treatment, the cured cat died in a road traffic accident. Upon full postmortem examination, including histopathology and immunohistochemistry, there were no residual FIP lesions observed apart from a generalized lymphadenopathy due to massive lymphoid hyperplasia. Neither feline coronavirus (FCoV) RNA nor FCoV antigen were identified by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunohistochemistry, respectively, in any tissues or body fluids, including feces. These results prove that oral treatment with GS-441524 leads to the cure of FIP-associated changes and the elimination of FCoV from all tissues.

Fecal Feline Coronavirus RNA Shedding and Spike Gene Mutations in Cats with Feline Infectious Peritonitis Treated with GS-441524

As previously demonstrated by our research group, the oral multicomponent drug Xraphconn^® containing GS-441524 was effective at curing otherwise fatal feline infectious peritonitis (FIP) in 18 feline coronavirus (FCoV)-infected cats. The aims of the current study were to investigate, using samples from the same animals as in the previous study, (1) the effect of treatment on fecal viral RNA shedding; (2) the presence of spike gene mutations in different body compartments of these cats; and (3) viral RNA shedding, presence of spike gene mutations, and anti-FCoV antibody titers in samples of 12 companion cats cohabitating with the treated cats. Eleven of the eighteen treated FIP cats (61%) were shedding FCoV RNA in feces within the first three days after treatment initiation, but all of them tested negative by day 6. In one of these cats, fecal shedding reoccurred on day 83. Two cats initially negative in feces were transiently positive 1–4 weeks into the study. The remaining five cats never shed FCoV. Viral RNA loads in feces decreased with time comparable with those in blood and effusion. Specific spike gene mutations linked to systemic FCoV spread were consistently found in blood and effusion from treated FIP cats, but not in feces from treated or companion cats. A new mutation that led to a not yet described amino acid change was identified, indicating that further mutations may be involved in the development of FIP. Eight of the twelve companion cats shed FCoV in feces. All but one of the twelve companion cats had anti-FCoV antibodies. Oral treatment with GS-441524 effectively decreased viral RNA loads in feces, blood, and effusion in cats with FIP. Nonetheless, re-shedding can most likely occur if cats are re-exposed to FCoV by their companion cats.

First molecular evidence of Mycoplasma haemocanis and 'Candidatus Mycoplasma haematoparvum' infections and its association with epidemiological factors in dogs from Cuba

Haemotrophic mycoplasmas (haemoplasmas) are unculturable, epicellular, cell wall-less gram-negative bacteria distributed worldwide, which infect several mammalian species. In dogs, Mycoplasma haemocanis and 'Candidatus Mycoplasma haematoparvum' have been reported as causative agents of infectious anaemia, especially in splenectomised or immunocompromised animals. The present cross-sectional study aims to assess the prevalence, risk factors, and molecular characterization of canine haemoplasmas in Cuba. A total of 391 dog blood samples and 247 tick samples were tested for the presence of canine haemoplasmas by species-specific quantitative TaqMan® real-time PCR assays. Overall, 17.9% (70/391; 95% CI: 14.1-21.7) blood samples were PCR-positive for at least one canine haemoplasmas species, where 15.1% (59/391; 95% CI: 11.5-18.7) for Mycoplasma haemocanis, 4.4% (17/391; 95% CI: 2.3-6.4) for 'Candidatus Mycoplasma haematoparvum', and 1.5% (6/391; 95% CI: 0.3-2.8) were co-infected. All collected ticks were identified morphologically as Rhipicephalus sanguineus sensu lato, and none of the tested tick samples was found PCR-positive for the presence of Mycoplasma haemocanis and 'Candidatus Mycoplasma haematoparvum'. Risk factors for canine haemoplasmas species infection included the presence of tick infestation, crossbreeding and living in kennels, while no association was found with the occurrence of anaemia. Phylogenetic analyses based on the 16S rRNA gene sequences of Mycoplasma haemocanis and 'Candidatus Mycoplasma haematoparvum' revealed >99% identity to other isolates distributed worldwide, indicating low genetic variability amongst these canine haemoplasmas species. To the best of the authors´ knowledge, this is the first molecular evidence of Mycoplasma haemocanis and 'Candidatus Mycoplasma haematoparvum' infections in dogs from Cuba.

A Pre- and Within-Pandemic Survey of SARS-CoV-2 RNA in Saliva Swabs from Stray Cats in Switzerland

Cats have been shown to be highly susceptible to SARS-CoV-2, and transmission within the species has been demonstrated experimentally. In cats undergoing natural SARS-CoV-2 infections, human-to-animal transmission was mostly suspected. It can be postulated that, in stray cats with no or only minimal contact with humans, SARS-CoV-2 may pose a minor risk. The current study investigated the prevalence of active SARS-CoV-2 infections in Swiss stray cats using quantitative reverse transcriptase real-time polymerase chain reaction (RT-qPCR). Saliva swabs from 1405 stray cats were collected in 14 Swiss cantons. The animals were sampled between February 2019 and February 2020 (pre-COVID-19 cohort: 523 cats) and between February 2020 and August 2021 (COVID-19 cohort: 882 cats). All the samples were tested by RT-qPCR, amplifying the envelope (E) gene and, in case of positive or inconclusive results, the RNA-dependent RNA polymerase (RdRp) gene of SARS-CoV-2. No SARS-CoV-2 viral RNA could be detected in any of the tested saliva swab samples. Our findings support the assumption that SARS-CoV-2 infections in stray cats are not highly prevalent in Switzerland. Nevertheless, the monitoring of stray cats and other susceptible animal species is necessary, since the “One Health” approach has been recognized as being essential to successfully fight the COVID-19 pandemic.

Cytauxzoon europaeus infections in domestic cats in Switzerland and in European wildcats in France: a tale that started more than two decades ago

BACKGROUND

Cytauxzoon spp. infection is believed to be a newly emerging tick-borne disease in felids in Europe, with three species of the haemoparasite having recently been differentiated in wild felids. In Switzerland, rare infections have been documented in domestic cats in the west and northwest of the country, the first of which was in 2014. The aims of the present study were: (i) to characterize a Cytauxzoon spp. hotspot in domestic cats in central Switzerland; (ii) to elucidate the geographic distribution of Cytauxzoon spp. in domestic cats in Switzerland; (iii) to assess suspected high-risk populations, such as stray and anaemic cats; and (iv) to investigate the newly emerging nature of the infection. Cytauxzoon spp. were further differentiated using mitochondrial gene sequencing.

METHODS

The overall study included samples from 13 cats from two households in central Switzerland (study A), 881 cats from all regions of Switzerland (study B), 91 stray cats from a hotspot region in the northwest of Switzerland and 501 anaemic cats from across Switzerland (study C), and 65 Swiss domestic cats sampled in 2003 and 34 European wildcats from eastern France sampled in the period 1995-1996 (study D). The samples were analysed for Cytauxzoon spp. using real-time TaqMan quantitative PCR, and positive samples were subjected to 18S rRNA, cytochrome b (CytB) and cytochrome c oxidase subunit I (COI) gene sequencing.

RESULTS

In study A, six of 13 cats from two neighbouring households in central Switzerland tested postive for Cytauxzoon spp.; two of the six infected cats died from bacterial infections. In studies B and C, only one of the 881 cats (0.1%; 95% confidence interval [CI]: 0-0.3%) in the countrywide survey and one of the 501 anaemic cats (0.2%; 95% CI: 0-0.6%) tested postive for Cytauxzoon spp. while eight of the 91 stray cats in the northwest of Switzerland tested positive (8.8%; 95% CI: 3.0-14.6%). In study D, Cytauxzoon spp. was detected in one of the 65 domestic cat samples from 2003 (1.5%; 95% CI: 0-4.5%) and in ten of the 34 European wildcat samples from 1995 to 1996 (29%; 95% CI: 14.2-44.7%). The isolates showed ≥ 98.6% sequence identities among the 18S rRNA, CytB and COI genes, respectively, and fell in the subclade Cytauxzoon europaeus based on CytB and COI gene phylogenetic analyses.

CONCLUSIONS

The study challenges the newly emerging nature of Cytauxzoon spp. in central Europe and confirms that isolates from domestic cats in Switzerland and European wild felids belong to the same species.

[SARS-CoV-2 infections in cats, dogs, and other animal species: Findings on infection and data from Switzerland]

INTRODUCTION

The pandemic with the novel coronavirus (SARS-CoV-2) has led to infections and deaths worldwide. Apart from humans, certain animal species are susceptible to the viral infection. Spillover between humans and animals is favored by close contact; thus, surveillance of animals is an important component to fight the pandemic from a One Health perspective. The Clinical Laboratory of the Vetsuisse Faculty Zurich has been investigating SARS-CoV-2 infections in animals since the beginning of the pandemic. In November 2020, the first SARS-CoV-2 positive Swiss cat was reported to the World Organisation for Animal Health (OIE-WAHIS). The cat showed respiratory signs and lived in a COVID-19 affected household. By now, over 500 natural SARS-CoV-2 infections have been recorded in animals worldwide. A prevalence study on SARS-CoV-2 infections in dogs and cats was carried out together with clinics from Germany and Italy during the first wave of the pandemic (March-July 2020). Among the tested 1137 animals, only one cat and one dog were positive. The prevalence of infection in dogs and cats presented to veterinary clinics was low, even in pandemic hotspot regions. However, recent studies that focused on animals in COVID-19 households found a higher prevalence of infection. A study is currently underway that specifically collects samples from pets from Swiss COVID-19 affected household and collects data on human-animal interaction.

Investigation on haplotypes of ixodid ticks and retrospective finding of Borrelia miyamotoi in bank vole (Myodes glareolus) in Switzerland

The current status of tick species, important tick-borne bacteria and protozoan parasites is well-documented in Switzerland. However, reports on the genetic diversity and geographical relationships of tick species in this country appear to be in part lacking or outdated. Thus, the aim of this study was to collect ticks from various host species in southern Switzerland, to compare them in a geographical context and to screen in these samples rare tick-borne pathogens hitherto not reported or having low prevalence in Switzerland. In 2019-2020 altogether 177 ixodid ticks were collected from the vegetation, as well as from humans (n = 17), dogs (n = 23), cats (n = 41), red deer (n = 8), a European rabbit and a European hedgehog at 25 locations in three cantons of south Switzerland. Tick species were identified morphologically, followed by DNA extraction and comparison of mitochondrial haplotypes with molecular-phylogenetic methods. Tick DNA extracts, as well as sixty-two rodent liver or spleen tissue DNA extracts (representing six species) available from 2005 to 2006 were screened for trypanosomes, Occidentia massiliensis and Borrelia miyamotoi. Morphologically, three tick species were identified: Ixodes ricinus (n = 170), Rhipicephalus sanguineus sensu lato (n = 6) and I. hexagonus (n = 1). In contrast to companion animals (dogs, cats) immature ticks (larvae and nymphs) predominated on humans, which was a highly significant association (P < 0.0001). Molecular comparison of the cytochrome c oxidase subunit I (cox1) gene with GenBank data established the species as R. sanguineus sensu stricto and confirmed I. hexagonus, both showing 99.8-100% sequence identity to conspecific ticks from northern Italy. Seventy-nine specimens morphologically identified as I. ricinus revealed high 16S rRNA gene haplotype diversity and represented two phylogenetic groups. Two I. ricinus haplotypes from Switzerland belonged to the same haplogroup with I. inopinatus from Spain, Germany and Austria as well as with I. ricinus reported from a broad geographical range of Europe (including Italy, the Netherlands, Poland, Latvia and Sweden). All 141 tick DNA extracts (from five R. sanguineus s.l., 135 I. ricinus and one I. hexagonus) and 62 rodent tissue DNA extracts were negative for trypanosomes and O. massiliensis. However, B. miyamotoi was identified in a bank vole (Myodes glareolus) and three ticks by sequencing. From Switzerland, this is the first report of tick haplotypes that are phylogenetically closely related to I. inopinatus. However, based on their morphology, both specimens are considered as I. ricinus. These results highlight the importance that the identification of I. inopinatus should be based on coherent morphologic and molecular properties. This is also the first report of rodent-borne B. miyamotoi in Switzerland. Taking into account the year of collection (2005), in a chronological order this might be the first indication of B. miyamotoi in any rodent species in Europe.

Management of Suspected Cases of Feline Immunodeficiency Virus Infection in Eurasian Lynx (Lynx lynx) During an International Translocation Program

The Eurasian lynx (Lynx lynx) population in Switzerland serves as a source for reintroductions in neighboring countries. In 2016–2017, three lynx from the same geographical area were found seropositive for feline immunodeficiency virus (FIV) in the framework of an international translocation program. This novel finding raised questions about the virus origin and pathogenicity to lynx, the emerging character of the infection, and the interpretation of serological results in other lynx caught for translocation. Archived serum samples from 84 lynx captured in 2001–2016 were retrospectively tested for FIV antibodies by Western blot. All archived samples were FIV-negative. The three seropositive lynx were monitored in quarantine enclosures prior to euthanasia and necropsy. They showed disease signs, pathological findings, and occurrence of co-infections reminding of those described in FIV-infected domestic cats. All attempts to isolate and characterize the virus failed but serological data and spatiotemporal proximity of the cases suggested emergence of a lentivirus with antigenic and pathogenic similarities to FIV in the Swiss lynx population. A decision scheme was developed to minimize potential health risks posed by FIV infection, both in the recipient and source lynx populations, considering conservation goals, animal welfare, and the limited action range resulting from local human conflicts. Development and implementation of a cautious decision scheme was particularly challenging because FIV pathogenic potential in lynx was unclear, negative FIV serological results obtained within the first weeks after infection are unpredictable, and neither euthanasia nor repatriation of multiple lynx was acceptable options. The proposed scheme distinguished between three scenarios: release at the capture site, translocation, or euthanasia. Until April 2021, none of the 40 lynx newly captured in Switzerland tested FIV-seropositive. Altogether, seropositivity to FIV was documented in none of 124 lynx tested at their first capture, but three of them seroconverted in 2016–2017. Diagnosis of FIV infection in the three seropositive lynx remains uncertain, but clinical observations and pathological findings confirmed that euthanasia was appropriate. Our experiences underline the necessity to include FIV in pathogen screenings of free-ranging European wild felids, the importance of lynx health monitoring, and the usefulness of health protocols in wildlife translocation.

Curing Cats with Feline Infectious Peritonitis with an Oral Multi-Component Drug Containing GS-441524

Feline infectious peritonitis (FIP) caused by feline coronavirus (FCoV) is a common dis-ease in cats, fatal if untreated, and no effective treatment is currently legally available. The aim of this study was to evaluate efficacy and toxicity of the multi-component drug Xraphconn^® in vitro and as oral treatment in cats with spontaneous FIP by examining survival rate, development of clinical and laboratory parameters, viral loads, anti-FCoV antibodies, and adverse effects. Mass spectrometry and nuclear magnetic resonance identified GS-441524 as an active component of Xraphconn^®. Eighteen cats with FIP were prospectively followed up while being treated orally for 84 days. Values of key parameters on each examination day were compared to values before treatment initiation using linear mixed-effect models. Xraphconn^® displayed high virucidal activity in cell culture. All cats recovered with dramatic improvement of clinical and laboratory parameters and massive reduction in viral loads within the first few days of treatment without serious adverse effects. Oral treatment with Xraphconn^® containing GS-441524 was highly effective for FIP without causing serious adverse effects. This drug is an excellent option for the oral treatment of FIP and should be trialed as potential effective treatment option for other severe coronavirus-associated diseases across species.

Modified-Live Feline Calicivirus Vaccination Elicits Cellular Immunity against a Current Feline Calicivirus Field Strain in an Experimental Feline Challenge Study

Feline calicivirus (FCV) is a common cat virus associated with oral ulcerations and virulent-systemic disease. Efficacious FCV vaccines protect against severe disease but not against infection. The high genetic diversity of FCV poses a challenge in vaccine design. Protection against FCV has been related to humoral and cellular immunity; the latter has not been studied in detail. This study investigates the cellular and humoral immune response of specified pathogen-free (SPF) cats after modified-live FCV F9 vaccinations and two heterologous FCV challenges by the analysis of lymphocyte subsets, cytokine mRNA transcription levels, interferon (IFN)-γ release assays in peripheral blood mononuclear cells (PBMCs), anti-FCV antibodies, and neutralisation activity. Vaccinated cats developed a Th1 cytokine response after vaccination. Vaccination resulted in antibodies with neutralising activity against the vaccine but not the challenge viruses. Remarkably, IFN-γ-releasing PBMCs were detected in vaccinated cats upon stimulation with the vaccine strain and the first heterologous FCV challenge strain. After the first experimental infection, the mRNA transcription levels of perforin, granzyme B, INF-γ, and antiviral factor MX1 and the number of IFN-γ-releasing PBMCs when stimulated with the first challenge virus were higher in vaccinated cats compared to control cats. The first FCV challenge induced crossneutralising antibodies in all cats against the second challenge virus. Before the second challenge, vaccinated cats had a higher number of IFN-γ-releasing PBMCs when stimulated with the second challenge virus than control cats. After the second FCV challenge, there were less significant differences detected between the groups regarding lymphocyte subsets and cytokine mRNA transcription levels. In conclusion, modified-live FCV vaccination induced cellular but not humoral crossimmunity in SPF cats; innate immune mechanisms, secretory and membranolytic pathways, and IFN-γ-releasing PBMCs seem to be important in the host immune defence against FCV.

Modified-Live Feline Calicivirus Vaccination Reduces Viral RNA Loads, Duration of RNAemia, and the Severity of Clinical Signs after Heterologous Feline Calicivirus Challenge

Feline calicivirus (FCV) is a common cat virus causing clinical signs such as oral ulcerations, fever, reduced general condition, pneumonia, limping and occasionally virulent-systemic disease. Efficacious FCV vaccines protect against severe disease but not against infection. FCV is a highly mutagenic RNA virus whose high genetic diversity poses a challenge in vaccine design. The use of only one modified-live FCV strain over several decades might have driven the viral evolution towards more vaccine-resistant variants. The present study investigated the clinical signs, duration, and amount of FCV shedding, RNAemia, haematological changes and acute phase protein reaction in SPF cats after subcutaneous modified-live single strain FCV vaccination or placebo injection and two subsequent oronasal heterologous FCV challenge infections with two different field strains. Neither clinical signs nor FCV shedding from the oropharynx and FCV RNAemia were detected after vaccination. After the first experimental infection, vaccinated cats had significantly lower clinical scores, less increased body temperature and lower acute phase protein levels than control cats. The viral RNA loads from the oropharynx and duration and amount of RNAemia were significantly lower in the vaccinated animals. No clinical signs were observed in any of the cats after the second experimental infection. In conclusion, FCV vaccination was beneficial for protecting cats from severe clinical signs, reducing viral loads and inflammation after FCV challenge.

SARS-CoV-2 Infection in Dogs and Cats from Southern Germany and Northern Italy during the First Wave of the COVID-19 Pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions of people globally since its first detection in late 2019. Besides humans, cats and, to some extent, dogs were shown to be susceptible to SARS-CoV-2, highlighting the need for surveillance in a One Health context. Seven veterinary clinics from regions with high incidences of coronavirus disease (COVID-19) were recruited during the early pandemic (March to July 2020) for the screening of patients. A total of 2257 oropharyngeal and nasal swab specimen from 877 dogs and 260 cats (including 18 animals from COVID-19-affected households and 92 animals with signs of respiratory disease) were analyzed for the presence of SARS-CoV-2 RNA using reverse transcriptase real-time polymerase chain reaction (RT-qPCR) targeting the viral envelope (E) and RNA dependent RNA polymerase (RdRp) genes. One oropharyngeal swab from an Italian cat, living in a COVID-19-affected household in Piedmont, tested positive in RT-qPCR (1/260; 0.38%, 95% CI: 0.01-2.1%), and SARS-CoV-2 infection of the animal was serologically confirmed six months later. One oropharyngeal swab from a dog was potentially positive (1/877; 0.1%, 95% CI: 0.002-0.63%), but the result was not confirmed in a reference laboratory. Analyses of convenience sera from 118 animals identified one dog (1/94; 1.1%; 95% CI: 0.02-5.7%) from Lombardy, but no cats (0/24), as positive for anti-SARS-CoV-2 receptor binding domain (RBD) antibodies and neutralizing activity. These findings support the hypothesis that the prevalence of SARS-CoV-2 infection in pet cat and dog populations, and hence, the risk of zoonotic transmission to veterinary staff, was low during the first wave of the pandemic, even in hotspot areas.

SARS-CoV-2 Infection and Antibody Response in a Symptomatic Cat from Italy with Intestinal B-Cell Lymphoma

Since the coronavirus disease (COVID-19) pandemic was first identified in early 2020, rare cases of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in pet cats have been reported worldwide. Some reports of cats with SARS-CoV-2 showed self-limiting respiratory or gastrointestinal disease after suspected human-to-feline transmission via close contact with humans with SARS-CoV-2. In the present study, we investigated a cat with SARS-CoV-2 that was presented to a private animal clinic in Northern Italy in May 2020 in a weak clinical condition due to an underlying intestinal B-cell lymphoma. The cat developed signs of respiratory tract disease, including a sneeze, a cough and ocular discharge, three days after an oropharyngeal swab tested positive for SARS-CoV-2 viral RNA using two real-time reverse transcriptase polymerase chain reaction (RT-qPCR) assays for the envelope (E) and RNA-dependent RNA polymerase (RdRp) gene. Thus, SARS-CoV-2 viral RNA was detectable prior to the onset of clinical signs. Five and six months after positive molecular results, the serological testing substantiated the presence of a SARS-CoV-2 infection in the cat with the detection of anti-SARS-CoV-2 receptor binding domain (RBD) immunoglobulin (IgG) antibodies and neutralizing activity in a surrogate virus neutralization assay (sVNT). To the best of our knowledge, this extends the known duration of seropositivity of SARS-CoV-2 in a cat. Our study provides further evidence that cats are susceptible to SARS-CoV-2 under natural conditions and strengthens the assumption that comorbidities may play a role in the development of clinical disease.

Detection and Genome Sequencing of SARS-CoV-2 in a Domestic Cat with Respiratory Signs in Switzerland

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.

Babesia gibsoni emerging with high prevalence and co-infections in “fighting dogs” in Hungary

Babesia gibsoni is considered as an emerging protozoan parasite of dogs in North America and Europe. However, no data have been published on its prevalence, molecular-phylogenetic characteristics and associated co-infections in dogs used for illegal fighting (i.e. predisposed to acquiring this piroplasm via biting) in Europe. In this study, blood samples from 79 American Staffordshire Terrier dogs, confiscated for illegal dog fights, were molecularly analyzed for tick-borne pathogens. Babesiagibsoni was detected in 32 dogs, i.e. with a prevalence of 40.5%. In addition, Babesia vulpes was found in 8 samples (prevalence of 10.1%), for the first time in dogs in Hungary. Canine hemoplasmas were also identified in 49 samples (62%): only Mycoplasma haemocanis in 32 (40.5%) dogs, only “Candidatus Mycoplasma haematoparvum” in 9 (11.4%) dogs, and both hemoplasmas in 8 (10.1%) dogs. Thus, hemoplasma infections also showed a particularly high prevalence in this dog population. Based on a partial fragment of the 18S rRNA gene, B. gibsoni from Hungary exhibited complete sequence identity with conspecific strains reported from Europe and Asia. The cytochrome c oxidase subunit 1 (cox1) gene sequence of this isolate showed the closest identity with B. gibsoni reported from Japan but had a nonsynonymous mutation (M33I). Furthermore, the 11 B. gibsoni-positive samples analyzed for sequence variants of the cytochrome b (cytb) gene showed the presence of a common mutation (P310S). Most importantly, B. gibsoni had two further nonsynonymous mutations, M121I and F258L, in a dog with severe and relapsing anemia following atovaquone treatment. Phylogenetically, both cytb sequence variants clustered together, with a clear geographical pattern showing the closest relationship of both haplotypes identified in Hungary with those from China and Japan. To the best of our knowledge, this is the first cox1 and cytb characterization of B. gibsoni in Europe, as well as the first report on the emergence of this piroplasm and hemoplasmas with high prevalence among “fighting dogs” north of the Mediterranean Basin.

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High prevalence of Babesia gibsoni and canine hemoplasmas in “fighting dogs”.

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Molecular evidence for infection with Babesia vulpes in dogs in Hungary.

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Closest identity with sequences from Asia in two of the three genetic markers tested.

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Two unique nonsynonymous mutations of B. gibsoni in the case of a dog.

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First report of atovaquone resistance for B. gibsoni in Europe.

Molecular Diagnosis, Prevalence and Importance of Zoonotic Vector-Borne Pathogens in Cuban Shelter Dogs-A Preliminary Study

The present study aimed to determine the prevalence of zoonotic vector-borne pathogens, including Anaplasma platys, Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Ehrlichia canis and Rickettsia spp. in shelter dogs from Cuba. Blood samples were collected from 100 shelter dogs and examined by molecular methods. Overall, 85 (85%; 95% CI: 77.88-92.12) dogs tested positive for at least one vector-borne pathogen using species-specific qPCR assays. Among the positive samples, E. canis was the most prevalent 62% (95% CI: 52.32-71.68), followed by A. platys 40% (95% CI: 30.23-49.77) and Rickettsia felis 27% (95% CI: 18.15-35.85), whereas 36% (95% CI: 26.43-45.57) showed co-infections. All samples were negative for A. phagocytophilum and B. burgdorferi s.l. The presence of 248 Rhipicephalus sanguineus ticks collected from the dogs was not statistically associated with the occurrence of infections. Thrombocytopenia was the most frequent haematological alteration found in PCR-positive dogs; it was statistically associated with the presence of E. canis, as well as co-infections (p < 0.05). The phylogenetic analyses of A. platys and E. canis based on 16S rRNA, groEL and gltA genes showed a low genetic diversity between Cuban strains. The present study demonstrates the high prevalence of vector-borne pathogens with zoonotic potential in shelter dogs from Cuba.

Molecular detection and characterization of Hepatozoon canis in stray dogs from Cuba

Canine hepatozoonosis caused by Hepatozoon canis is a worldwide distributed tick-borne disease of domestic and wild canids that is transmitted by ingestion of Rhipicephalus sanguineus sensu lato (s.l.) ticks. The present study was aimed to determine the prevalence of Hepatozoon infections in 80 stray dogs from Havana Province in Cuba, and to confirm the species identity and phylogenetic relationships of the causative agent. Samples were screened by microscopical examination of thin blood smears for the presence of Hepatozoon spp. gamonts and by genus-specific SYBR green-based real-time PCR assay targeting the 18S rRNA gene. Direct microscopy examination revealed Hepatozoon gamonts in the peripheral blood of 8 dogs (10.0%; 95% CI: 4.80-18.0%), while 38 animals (47.5%; 95% CI: 36.8-58.4%) were PCR-positive, including all microscopically positive dogs. Hence, the agreement between the two detection methods was 'poor' (κ = 0.20). Hematological parameters did not differ significantly between PCR-positive and PCR-negative dogs (p > 0.05). The DNA sequences of the 18S rRNA gene of the Hepatozoon spp. from Cuban dogs showed a nucleotide identity >99% with those of 18S rRNA sequences of Hepatozoon canis isolates from Czech Republic, Brazil and Spain. Phylogenetic analysis revealed that obtained sequences clustered within the Hepatozoon canis clade, different from the Hepatozoon felis or Hepatozoon americanum clades. The present study represents the first molecular characterization of Hepatozoon canis in stray dogs within Cuba.

FCoV Viral Sequences of Systemically Infected Healthy Cats Lack Gene Mutations Previously Linked to the Development of FIP

Feline Infectious Peritonitis (FIP)—the deadliest infectious disease of young cats in shelters or catteries—is induced by highly virulent feline coronaviruses (FCoVs) emerging in infected hosts after mutations of less virulent FCoVs. Previous studies have shown that some mutations in the open reading frames (ORF) 3c and 7b and the spike (S) gene have implications for the development of FIP, but mainly indirectly, likely also due to their association with systemic spread. The aim of the present study was to determine whether FCoV detected in organs of experimentally FCoV infected healthy cats carry some of these mutations. Viral RNA isolated from different tissues of seven asymptomatic cats infected with the field strains FCoV Zu1 or FCoV Zu3 was sequenced. Deletions in the 3c gene and mutations in the 7b and S genes that have been shown to have implications for the development of FIP were not detected, suggesting that these are not essential for systemic viral dissemination. However, deletions and single nucleotide polymorphisms leading to truncations were detected in all nonstructural proteins. These were found across all analyzed ORFs, but with significantly higher frequency in ORF 7b than ORF 3a. Additionally, a previously unknown homologous recombination site was detected in FCoV Zu1.

Prevalence and phylogeny of Chlamydiae and hemotropic mycoplasma species in captive and free-living bats

BACKGROUND

Bats are hosts for a variety of microorganisms, however, little is known about the presence of Chlamydiales and hemotropic mycoplasmas. This study investigated 475 captive and free-living bats from Switzerland, Germany, and Costa Rica for Chlamydiales and hemotropic mycoplasmas by PCR to determine the prevalence and phylogeny of these organisms.

RESULTS

Screening for Chlamydiales resulted in a total prevalence of 31.4%. Positive samples originated from captive and free-living bats from all three countries. Sequencing of 15 samples allowed the detection of two phylogenetically distinct groups. These groups share sequence identities to Chlamydiaceae, and to Chlamydia-like organisms including Rhabdochlamydiaceae and unclassified Chlamydiales from environmental samples, respectively. PCR analysis for the presence of hemotropic mycoplasmas resulted in a total prevalence of 0.7%, comprising free-living bats from Germany and Costa Rica. Phylogenetic analysis revealed three sequences related to other unidentified mycoplasmas found in vampire bats and Chilean bats.

CONCLUSIONS

Bats can harbor Chlamydiales and hemotropic mycoplasmas and the newly described sequences in this study indicate that the diversity of these bacteria in bats is much larger than previously thought. Both, Chlamydiales and hemotropic mycoplasmas are not restricted to certain bat species or countries and captive and free-living bats can be colonized. In conclusion, bats represent another potential host or vector for novel, previously unidentified, Chlamydiales and hemotropic mycoplasmas.

Treatment with Class A CpG Oligodeoxynucleotides in Cats with Naturally Occurring Feline Parvovirus Infection: A Prospective Study

Feline parvovirus (FPV) causes severe gastroenteritis and leukopenia in cats; the outcome is poor. Information regarding specific treatments is lacking. Class A CpG oligodeoxynucleotides (CpG-A) are short single-stranded DNAs, stimulating type I interferon production. In cats, CpG-A induced an antiviral response in vivo and inhibited FPV replication in vitro. The aim was to prospectively investigate the effects of CpG-A on survival, clinical score, hematological findings, antiviral response (cytokines), viremia, and fecal shedding (real-time qPCR) in cats naturally infected with FPV. Forty-two FPV-infected cats were randomized to receive 100 µg/kg of CpG-A (n = 22) or placebo (n = 20) subcutaneously, on admission and after 48 h. Blood and fecal samples were collected on admission, after 1, 3, and 7 days. All 22 cats showed short duration pain during CpG-A injections. The survival rate, clinical score, leukocyte and erythrocyte counts, viremia, and fecal shedding at any time-point did not differ between cats treated with CpG-A (50%) and placebo (40%). Antiviral myxovirus resistance (Mx) gene transcription increased in both groups from day 1 to 3 (p = 0.005). Antibodies against FPV on admission were associated with survival in cats (p = 0.002). In conclusion, CpG-A treatment did not improve the outcome in cats with FPV infection. FPV infection produced an antiviral response.

Bayesian Network Modeling Applied to Feline Calicivirus Infection Among Cats in Switzerland

Bayesian network (BN) modeling is a rich and flexible analytical framework capable of elucidating complex veterinary epidemiological data. It is a graphical modeling technique that enables the visual presentation of multi-dimensional results while retaining statistical rigor in population-level inference. Using previously published case study data about feline calicivirus (FCV) and other respiratory pathogens in cats in Switzerland, a full BN modeling analysis is presented. The analysis shows that reducing the group size and vaccinating animals are the two actionable factors directly associated with FCV status and are primary targets to control FCV infection. The presence of gingivostomatitis and Mycoplasma felis is also associated with FCV status, but signs of upper respiratory tract disease (URTD) are not. FCV data is particularly well-suited to a network modeling approach, as both multiple pathogens and multiple clinical signs per pathogen are involved, along with multiple potentially interrelated risk factors. BN modeling is a holistic approach—all variables of interest may be mutually interdependent—which may help to address issues, such as confounding and collinear factors, as well as to disentangle directly vs. indirectly related variables. We introduce the BN methodology as an alternative to the classical uni- and multivariable regression approaches commonly used for risk factor analyses. We advise and guide researchers about how to use BNs as an exploratory data tool and demonstrate the limitations and practical issues. We present a step-by-step case study using FCV data along with all code necessary to reproduce our analyses in the open-source R environment. We compare and contrast the findings of the current case study using BN modeling with previous results that used classical regression techniques, and we highlight new potential insights. Finally, we discuss advanced methods, such as Bayesian model averaging, a common way of accounting for model uncertainty in a Bayesian network context.

Development and application of a multiplex TaqMan® real-time qPCR assay for the simultaneous detection of Anaplasma marginale and Theileria annulata and molecular characterization of Anaplasma marginale from cattle in Western Cuba

Anaplasmosis and theileriosis are considered the most important tick-borne diseases for livestock production worldwide, causing significant economic losses in tropical and subtropical regions. The present study was aimed to develop a multiplex TaqMan® qPCR assay to simultaneously detect Anaplasma marginale and Theileria annulata and to applied it to investigate naturally infected cattle in Cuba. The assay was highly specific, sensible, and efficient; it was more sensitive than a well-established nested PCR and detected 1 DNA copy of each target. Consistent repeatability and reproducibility within and between multiplex qPCR runs was shown. A total of 223 blood samples collected in western Cuba were analyzed for haemoparasites infection in cattle. The multiplex qPCR assay detected A. marginale in 213 samples (95.5%; CI: 95%; 91.9%-97.5%), but all samples were negative for T. annulata. Additionally, the genetic diversity of A. marginale was assessed using 16S rRNA, MSP1a and MSP4 nucleotide and protein sequences. The MSP1a tandem repeats ranged from three to five, and twelve different MSP1a tandem repeats of A. marginale were found, which presented genotypes C, E, and G in the 5'UTR microsatellite region. Phylogenetic analysis using the msp4 gene showed that Cuban strains were closely related to others previously reported in Mexico, Brazil and Asian countries. The multiplex qPCR described here proved to be a rapid, specific and cost-effective mean for the simultaneous detection of A. marginale and T. annulata. Further epidemiological studies using this assay will improve the surveillance of the associated diseases in regions where they are endemic.

Feline Infectious Peritonitis as a Systemic Inflammatory Disease: Contribution of Liver and Heart to the Pathogenesis

Feline infectious peritonitis (FIP) is a fatal immune-mediated disease of cats, induced by feline coronavirus (FCoV). A combination of as yet poorly understood host and viral factors combine to cause a minority of FCoV-infected cats to develop FIP. Clinicopathological features include fever, vasculitis, and serositis, with or without effusions; all of which indicate a pro-inflammatory state with cytokine release. As a result, primary immune organs, as well as circulating leukocytes, have thus far been of most interest in previous studies to determine the likely sources of these cytokines. Results have suggested that these tissues alone may not be sufficient to induce the observed inflammation. The current study therefore focussed on the liver and heart, organs with a demonstrated ability to produce cytokines and therefore with huge potential to exacerbate inflammatory processes. The IL-12:IL-10 ratio, a marker of the immune system's inflammatory balance, was skewed towards the pro-inflammatory IL-12 in the liver of cats with FIP. Both organs were found to upregulate mRNA expression of the inflammatory triad of cytokines IL-1β, IL-6, and TNF-α in FIP. This amplifying step may be one of the missing links in the pathogenesis of this enigmatic disease.

Pan-European Study on the Prevalence of the Feline Leukaemia Virus Infection - Reported by the European Advisory Board on Cat Diseases (ABCD Europe)

Feline leukaemia virus (FeLV) is a retrovirus associated with fatal disease in progressively infected cats. While testing/removal and vaccination led to a decreased prevalence of FeLV, recently, this decrease has reportedly stagnated in some countries. This study aimed to prospectively determine the prevalence of FeLV viraemia in cats taken to veterinary facilities in 32 European countries. FeLV viral RNA was semiquantitatively detected in saliva, using RT-qPCR as a measure of viraemia. Risk and protective factors were assessed using an online questionnaire to report geographic, demographic, husbandry, FeLV vaccination, and clinical data. The overall prevalence of FeLV viraemia in cats visiting a veterinary facility, of which 10.4% were shelter and rescue cats, was 2.3% (141/6005; 95% CI: 2.0%–2.8%) with the highest prevalences in Portugal, Hungary, and Italy/Malta (5.7%–8.8%). Using multivariate analysis, seven risk factors (Southern Europe, male intact, 1–6 years of age, indoor and outdoor or outdoor-only living, living in a group of ≥5 cats, illness), and three protective factors (Northern Europe, Western Europe, pedigree cats) were identified. Using classification and regression tree (CART) analysis, the origin of cats in Europe, pedigree, and access to outdoors were important predictors of FeLV status. FeLV-infected sick cats shed more viral RNA than FeLV-infected healthy cats, and they suffered more frequently from anaemia, anorexia, and gingivitis/stomatitis than uninfected sick cats. Most cats had never been FeLV-vaccinated; vaccination rates were indirectly associated with the gross domestic product (GDP) per capita. In conclusion, we identified countries where FeLV was undetectable, demonstrating that the infection can be eradicated and highlighting those regions where awareness and prevention should be increased.

Fatal acute babesiosis associated with Babesia venatorum infection (Babesia sp. EU1) in a captive reindeer calf in Switzerland

Babesia venatorum was isolated from a captive reindeer calf in Switzerland. The clinical signs consistent with acute babesiosis included hemolytic anemia and hemoglobinuria. The diagnosis was made based on visualization of intraerythrocytic parasites in the stained blood smears and confirmed by PCR analysis of the 18S rRNA gene, with subsequent species identification within Babesia confirmed by sequencing. The reindeer calf was initially treated with supportive care and an antiprotozoal drug (imidocarb dipropionate) but died a few days after hospitalization. Babesia venatorum is also known as Babesia sp. EU1 and can infect different mammalian species, including humans. The current case report aims to increase awareness among veterinarians and reindeer owners about the presence and the associated risk of this zoonotic pathogen. Considering the high morbidity and possible mortality associated with acute babesiosis, captive reindeer should receive tick prevention measures and be tested for subclinical infections in endemic area.

First molecular evidence of bovine hemoplasma species (Mycoplasma spp.) in water buffalo and dairy cattle herds in Cuba

BACKGROUND

Hemotropic mycoplasmas (aka hemoplasmas) are small bacteria which cause infectious anemia in several mammalian species including humans. Information on hemoplasma infections in Cuban bovines remains scarce and no studies applying molecular methods have been performed so far. The aim of the present study was to utilize real-time PCR and sequence analysis to investigate dairy cattle and buffalo from Cuba for the presence of bovine hemoplasma species.

RESULTS

A total of 80 blood samples from 39 buffalo and 41 dairy cattle were investigated for the presence of Mycoplasma wenyonii and "Candidatus Mycoplasma haemobos" using two species-specific real-time TaqMan PCR assays. PCR results revealed overall 53 (66.2%; 95% CI: 55.3-75.7%) positive animals for M. wenyonii and 33 (41.2%; 95% CI: 31.1-52.2%) for "Ca. M. haemobos"; the latter were all co-infections with M. wenyonii. The sample prevalences were similar in cattle and buffalo. Based on the sequence analysis of the nearly full-length 16S rRNA gene from two cattle and two buffalo, the presence of M. wenyonii and "Ca. M. haemobos" was confirmed. Statistical analysis revealed that buffalo and cattle one year of age or older were more frequently infected with M. wenyonii or "Ca. M. haemobos" than younger animals. PCR-positivity was not associated with anemia; however, the infection stage was unknown (acute infection versus chronic carriers).

CONCLUSIONS

The high occurrence of bovine hemoplasma infections in buffalo and dairy cattle may have a significant impact on Cuban livestock production. To the best of our knowledge, this is the first molecular evidence of bovine hemoplasma species infection in dairy cattle and buffalo from Cuba and the Caribbean.

Inflammatory Mediators in the Mesenteric Lymph Nodes, Site of a Possible Intermediate Phase in the Immune Response to Feline Coronavirus and the Pathogenesis of Feline Infectious Peritonitis?

Feline infectious peritonitis (FIP) is an almost invariably fatal feline coronavirus (FCoV)-induced disease thought to arise from a combination of viral mutations and an overexuberant immune response. Natural initial enteric FCoV infection may remain subclinical, or result in mild enteric signs or the development of FIP; cats may also carry the virus systemically with no adverse effect. This study screened mesenteric lymph nodes (MLNs), the presumed first site of FCoV spread from the intestine regardless of viraemia, for changes in the transcription of a panel of innate immune response mediators in response to systemic FCoV infection and with FIP, aiming to identify key pathways triggered by FCoV. Cats with and without FIP, the latter with and without FCoV infection in the MLN, were compared. Higher expression levels in FIP were found for toll-like receptors (TLRs) 2, 4 and 8. These are part of the first line of defence and suggest a response to both viral structural proteins and viral nucleic acid. Expression of genes encoding inflammatory cytokines and chemokines, including interleukin (IL)-1β, IL-6, IL-15, tumour necrosis factor (TNF)-α, CXCL10, CCL8, interferon (IFN)-α, IFN-β and IFN-γ, was higher in cats with FIP, consistent with inflammatory pathway activation. Expression of genes encoding transcription factors STAT1 and 2, regulating signalling pathways, particularly of the interferons, was also higher. Among cats without FIP, there were few differences between virus-positive and virus-negative MLNs; however, TLR9 and STAT2 expression were higher with infection, suggesting a direct viral effect. The study provides evidence for TLR involvement in the response to FCoV. This could open up new avenues for therapeutic approaches.

First report of Cytauxzoon sp. infection in domestic cats in Switzerland: natural and transfusion-transmitted infections

BACKGROUND

Cytauxzoonosis is an emerging tick-borne disease of domestic and wild felids. Cytauxzoon felis induces severe and often fatal disease in domestic cats. In Europe, clinical and subclinical infections caused by Cytauxzoon sp. are described. We report the first cases of Cytauxzoon sp. infection in domestic cats in Switzerland.

METHODS

Clinical and laboratory data and results of PCR analyses were collected from Cytauxzoon sp. PCR-positive cats and the cats followed for up to 851 days.

RESULTS

The cases were three two-month old kittens from the same litter (Cases 1-3) and two adult domestic shorthair cats (Cases 4 and 5). The cats originated from the north-west and west of Switzerland. Cases 1-3 presented with moderate to severe regenerative anaemia and intraerythrocytic inclusions. Cytauxzoon sp. was confirmed by PCR and sequencing. The kittens made a clinical and haematological recovery after blood transfusion and/or treatment with azithromycin and atovaquone, but erythroparasitaemia persisted. Case 4 presented with severe non-regenerative anaemia. Case 5 was healthy and used as a blood donor for Case 4. Following blood transfusion, Case 4 showed intraerythrocytic inclusions, and Cytauxzoon sp. was confirmed in both Cases 4 and 5 using PCR and sequencing. Case 4 achieved clinical and haematological remission after treatment with azithromycin, atovaquone and immunosuppressive drugs. Eight months later, Case 4 was presented again with anaemia but tested Cytauxzoon sp. PCR-negative. Sequencing of 1637 bp of the 18S rRNA gene of Cytauxzoon sp. revealed 100% nucleotide sequence identity among isolates of Cases 1-3 and between isolates of Cases 4 and 5, and 99% sequence identity between isolates of all cases. Phylogenetic analysis revealed the closest relationship of the Swiss isolates to Cytauxzoon sp. isolates from domestic cats and wild felids from France, Spain and Romania and to Cytauxzoon manul from a Pallas's cat.

CONCLUSIONS

This is the first report of Cytauxzoon sp. infection in domestic cats in Switzerland. It is also the first report of infection in very young kittens and transmission of Cytauxzoon sp. to an adult cat by transfusion of blood from an asymptomatic cat. The cats recovered but some developed chronic asymptomatic erythroparasitaemia for up to 28 months. Domestic cats may act as reservoirs for Cytauxzoon sp. in Europe and blood donor cats should be screened for this agent by PCR.

Tick- and fly-borne bacteria in ungulates: the prevalence of Anaplasma phagocytophilum, haemoplasmas and rickettsiae in water buffalo and deer species in Central Europe, Hungary

Background

Hunting constitutes an important industry in Europe. However, data on the prevalence of vector-borne bacteria in large game animal species are lacking from several countries. Blood or spleen samples (239 and 270, respectively) were taken from red, fallow and roe deer, as well as from water buffaloes, mouflons and wild boars in Hungary, followed by DNA extraction and molecular analyses for Anaplasma phagocytophilum, haemoplasmas and rickettsiae.

Results

Based on blood samples, the prevalence rate of A. phagocytophilum infection was significantly higher in red deer (97.9%) than in fallow deer (72.7%) and roe deer (60%), and in all these compared to mouflons (6.3%). In addition, 39.2% of the spleen samples from wild boars were PCR positive for A. phagocytophilum, but none of the buffalos. Based on blood samples, the prevalence rates of both Mycoplasma wenyonii (Mw) and ‘Candidatus M. haemobos’ (CMh) infections were significantly higher in buffaloes (Mw: 91.2%; CMh: 73.3%) than in red deer (Mw: 64.6%; CMh: 45.8%), and in both of them compared to fallow deer (Mw: 30.3%; CMh: 9.1%) and roe deer (Mw: 20%; CMh: 1.5%). The prevalence of Mw and CMh infection significantly correlated with the body sizes of these hosts. Furthermore, Mw was significantly more prevalent than CMh in buffaloes, red and roe deer. Mycoplasma ovis was detected in mouflons, M. suis in wild boars, R. helvetica in one fallow deer and one mouflon, and an unidentified Rickettsia sp. in a fallow deer.

Conclusions

Forest-dwelling game animal species were found to be important carriers of A. phagocytophilum. In contrast, animals grazing grassland (i.e. buffaloes) were less likely to get infected with this Ixodes ricinus-borne pathogen. Water buffaloes, deer species, mouflons and wild boars harbored haemoplasmas that may affect domestic ungulates. Evaluated animals with larger body size had significantly higher prevalence of infection with haemoplasmas compared to smaller deer species. The above host species rarely carried rickettsiae.

Evidence for host specificity of Theileria capreoli genotypes in cervids

Data on the prevalence of piroplasms in buffaloes and large game animal species are lacking from several central European countries. Therefore, to investigate the presence of Babesia/Theileria DNA in these hosts, 239 blood and 270 spleen samples were taken from cervids (red, fallow, and roe deer), as well as from water buffaloes, mouflons, and wild boars in southwestern Hungary, followed by DNA extraction and molecular analysis for piroplasms. All samples from buffaloes and wild boars were PCR negative. Based on spleen samples, the prevalence of piroplasms was significantly higher in red deer (41.7%) than in fallow deer (23.5%). Two genotypes of Theileria capreoli were identified, which showed significant association with their host species (i.e. genotype “capreoli-CE1” was exclusively found in roe deer, whereas red and fallow deer harbored only genotype “elaphi-CE1”). Genotype “elaphi-CE1” of T. capreoli was also detected in one mouflon. No Babesia spp. were identified. In conclusion, in the evaluated region, genotypes of T. capreoli show host-associations among cervids, and at least one of these genotypes may infect mouflons.

Molecular detection of feline calicivirus in clinical samples: A study comparing its detection by RT-qPCR directly from swabs and after virus isolation

Feline caliciviruses (FCVs) are non-enveloped RNA viruses that exhibit high genetic variation. Two reverse transcription quantitative polymerase chain reaction (RT-qPCR) FCV assays (S1 and S2) were evaluated using samples from 300 field cats. The direct detection of FCV in swabs and after propagation in cell culture, as well as the influence of storage conditions, was assessed. FCV-RNA detectability on dry swabs was similar after storage at either 4°C or -20°C, but viral burdens were maintained for a longer time period when viral transport medium was used. A total of 97 (32%) samples was considered FCV PCR-positive. Of these, 81% and 77% tested positive directly from swabs using S1 and S2, respectively; 84% and 81% tested positive after enrichment in cell culture, respectively. Combined detection by RT-PCR directly from swabs and after VI was most sensitive (up to 96%). Neither of the methods alone were able to detect all FCV-positive samples. In conclusion, clinical samples should be collected in viral transport medium, stored at ≤4°C and processed as soon as possible. The combination of cell culture with RT-qPCR or detection directly from swabs using a combination of different RT-qPCR assays is recommended to reach a high sensitivity of FCV detection.

The effects of cryopreservation on the expression of canine regulatory T-cell markers

BACKGROUND

Regulatory T (Treg) cells have been described as key regulators in various immunological processes and are of growing interest in veterinary allergy. Cryopreservation of immune cells is performed routinely in human basic science research and in clinical studies. As such, it allows batch testing of collected samples at a single time point, resulting in a significant reduction in sample variability. Data which describe the effects of cryopreservation on Treg cell frequency and functionality in the canine species are important to inform future research.

HYPOTHESIS/OBJECTIVES

The purpose of this study was to establish a robust freeze/thaw procedure and flow cytometric staining protocol for canine Treg cells, and to compare the frequencies of different canine Treg cell phenotypes before and after cryopreservation.

ANIMALS

Nine privately owned dogs.

METHODS

Peripheral blood mononuclear cells were isolated and Treg cells stained and analysed by flow cytometry, before and after three months of cryopreservation. The recovery percentages and the corresponding correlations (fresh versus cryopreserved) for CD4⁺ CD25⁺ , CD4⁺ FOXP3⁺ and CD4⁺ CD25⁺ FOXP3⁺ cell populations were calculated.

RESULTS

A high recovery rate of 97.2 (r = 0.94, P < 0.0001), 93.9 (r = 0.77, P < 0.01) and 101.7% (r = 0.99, P < 0.0001) for CD4⁺ CD25⁺ , CD4⁺ FOXP3⁺ and CD4⁺ CD25⁺ FOXP3⁺ cell populations, respectively, was observed.

CONCLUSIONS

This study demonstrates an optimized protocol for freezing, thawing and quantifying canine Treg cells. These results indicate that cryopreservation does not substantially affect the expression of surface and intracellular markers of canine Treg cells; however, additional studies will be necessary to assess whether functionality of the cells is also maintained.

Seasonally biased or single-habitat sampling is not informative on the real prevalence of Dermacentor reticulatus-borne rickettsiae - A pilot study

Dermacentor reticulatus is a tick species of high medical and veterinary importance, emerging in several parts of Europe. Up to now most studies focusing on zoonotic rickettsiae in D. reticulatus were based on ticks collected in a limited part of the questing period, and did not take into account the potential seasonal variations in the rate of infection with tick-borne rickettsiae. The aim of the present study was to investigate the latter phenomenon, i.e. to screen D. reticulatus adults, collected monthly in two urban habitats of Budapest, for the presence of three zoonotic Rickettsia spp. Altogether 852 D. reticulatus adults were collected, which showed significantly similar seasonal activity in the two evaluated habitats. Among the 413 molecularly analysed ticks, R. helvetica-infected D. reticulatus were only collected during autumn in habitat-1, in contrast to habitat-2. The overall prevalence of R. raoultii in D. reticulatus adults was significantly higher in habitat-1 than in habitat-2. In addition, the seasonal distribution of R. raoultii-infected ticks was different between the two habitats (in habitat-2 significantly more R. raoultii-infected ticks were collected in the autumn, in comparison with winter and spring). Rickettsia slovaca was not detected in any of the molecularly analysed ticks. The results clearly indicate that a single-time or seasonally biased collection of D. reticulatus adults and their subsequent molecular analysis may not be informative on the real prevalence of rickettsiae. This is because the availability/ activity of infected ticks shows significant seasonal fluctuations, both within and between habitats. Instead, for screening D. reticulatus-borne rickettsiae, it is important to collect monthly samples and then to assess seasonal prevalence and actual habitat-associated eco-epidemiological risks.

Detection of 'Candidatus Neoehrlichia mikurensis' and other Anaplasmataceae and Rickettsiaceae in Canidae in Switzerland and Mediterranean countries

INTRODUCTION

'Candidatus Neoehrlichia mikurensis' is an emerging tick-borne zoonotic agent that primarily affects immunocompromised human patients. Dogs and foxes are frequently exposed to ticks, and both species are in close proximity to humans. This is the first study to systematically investigate the occurrence of 'Candidatus Neoehrlichia mikurensis' in Canidae in Europa. We analyzed 1'739 blood samples from dogs in Switzerland, Italy, Spain and Portugal and 162 blood samples from free-ranging red foxes (Vulpes vulpes) in Switzerland. All samples were tested using a previously described multiplex real-time PCR for the Anaplasmataceae family, the 'Candidatus Neoehrlichia' genus and the 'Candidatus Neoehrlichia mikurensis' species. All Anaplasmataceae positive samples were subsequently tested using specific real-time PCRs for Anaplasma phagocytophilum, Anaplasma platys, Ehrlichia canis and Rickettsia helvetica. Among the tested animals, one dog from Zurich tested positive for 'Candidatus Neoehrlichia mikurensis'. The 12-year old West Highland white terrier had been splenectomized 3 months prior to the blood collection and presented with polyuria/polydipsia. Fanconi syndrome was diagnosed based on glucosuria with normoglycemia and hyperaminoaciduria. A. platys and E. canis were detected in 14/249 dogs from Sicily and Portugal; two of the dogs were coinfected with both agents. Four Swiss foxes tested positive for A. phagocytophilium. R. helvetica was detected for the first time in a red fox. In conclusion, 'Candidatus Neoehrlichia mikurensis' infection should be considered in sick dogs, particularly when immunocompromised. The pathogen seems not to be widespread in Canidae in the investigated countries. Conversely, other Anaplasmataceae were more readily detected in dogs and foxes.

Genetic diversity and phenotypic associations of feline caliciviruses from cats in Switzerland

Feline calicivirus (FCV) is a common viral pathogen in domestic cats worldwide. The variable regions of the capsid (VP1) gene of FCV have one of the highest recorded rates of molecular evolution. Understanding the genetic diversity and phylogeny of FCV is a prerequisite to exploring the epidemiology and pathogenesis of this virus and to the development of efficacious vaccine strategies. In this study, we undertook a nationwide molecular characterization of FCV using for the first time nearly complete capsid (VP1) gene sequences. Sequences from 66 FCV samples were used to investigate the correlation between viral phylogeny and several traits, including geographic origin, signalment, husbandry, FCV vaccination and co-infections. Codon-based nucleotide alignment showed that individual nucleotides and their corresponding amino acid sites were either invariant or highly variable. Using a threshold of 20 % genetic distance in variable region E, FCV samples were grouped into 52 strains, 10 of which comprised two to three samples. Significant associations between FCV phylogeny and host characteristics were found, specifically the pedigree status of the cats, and two well-supported lineages were identified in which the current FCV strain definition was confounded. No correlation between viral genetic distances and geographic distances was evident. The greater resolution of the FCV phylogeny in this study compared to previous studies can be attributed to our use of more conserved regions of the capsid (VP1) gene; nonetheless, our results were still hampered by sequence saturation. The study highlights the need for whole-genome sequences for FCV phylogeny studies.