Neurotropic Highly Pathogenic Avian Influenza A(H5N1) Virus in Red Foxes, Northern Germany.

In a 1-year survey of wild terrestrial predators in northern Germany, we found that 5 of 110 foxes were infected with contemporary avian influenza A(H5N1) viruses, forming a temporal cluster during January‒March 2023. Encephalitis and strong cerebral virus replication but only sporadic mammalian-adaptive viral polymerase basic 2 protein E627K mutations were seen.

Interdisciplinary studies on Coxiella burnetii: From molecular to cellular, to host, to one health research.

The Q-GAPS (Q fever GermAn interdisciplinary Program for reSearch) consortium was launched in 2017 as a German consortium of more than 20 scientists with exceptional expertise, competence, and substantial knowledge in the field of the Q fever pathogen Coxiella (C.) burnetii. C. burnetii exemplifies as a zoonotic pathogen the challenges of zoonotic disease control and prophylaxis in human, animal, and environmental settings in a One Health approach. An interdisciplinary approach to studying the pathogen is essential to address unresolved questions about the epidemiology, immunology, pathogenesis, surveillance, and control of C. burnetii. In more than five years, Q-GAPS has provided new insights into pathogenicity and interaction with host defense mechanisms. The consortium has also investigated vaccine efficacy and application in animal reservoirs and identified expanded phenotypic and genotypic characteristics of C. burnetii and their epidemiological significance. In addition, conceptual principles for controlling, surveilling, and preventing zoonotic Q fever infections were developed and prepared for specific target groups. All findings have been continuously integrated into a Web-based, interactive, freely accessible knowledge and information platform (www.q-gaps.de), which also contains Q fever guidelines to support public health institutions in controlling and preventing Q fever. In this review, we will summarize our results and show an example of how an interdisciplinary consortium provides knowledge and better tools to control a zoonotic pathogen at the national level.

Holoprosencephalia, hypoplasia of corpus callosum and cerebral heterotopia in a male belted Galloway heifer with adipsia.

BACKGROUND: Specialized neurons in the diencephalon detect blood hypernatremia in dehydrated animals. These neurons are connected with the pituitary gland, subsequently producing antidiuretic hormone to reabsorb water from urine in the kidneys, and to the forebrain to generate thirst and trigger drinking behavior. CASE PRESENTATION: This is the first case report describing clinical findings, magnetic resonance imaging (MRI) and necropsy results of a Belted Galloway heifer with severe clinical signs of dehydration and hypernatremia, but concurrent adipsia and isosthenuria. Due to insufficient recovery with symptomatic treatment, owners elected euthanasia. Postmortem MRI and necropsy revealed a complex forebrain malformation: mild abnormal gyrification of the forebrain cortex, lobar holoprosencephaly, and corpus callosum hypoplasia. The affected brain structures are well known to be involved in osmoregulation and generation of thirst in dogs, humans and rodents. CONCLUSIONS: Complex forebrain malformation can be involved in the pathogenesis of hypernatremia and adipsia in bovines.

Geographic Distribution of Raccoon Roundworm, Baylisascaris procyonis, Germany and Luxembourg.

Infestation with Baylisascaris procyonis, a gastrointestinal nematode of the raccoon, can cause fatal disease in humans. We found that the parasite is widespread in central Germany and can pose a public health risk. The spread of B. procyonis roundworms into nematode-free raccoon populations needs to be monitored.

[Leptospirosis in Germany: current knowledge on pathogen species, reservoir hosts, and disease in humans and animals]. / Leptospirose in Deutschland: Aktuelle Erkenntnisse zu Erregerspezies, Reservoirwirten und Erkrankungen bei Mensch und Tier.

Leptospirosis is a zoonotic disease with a wide spectrum of clinical symptoms in humans and animals, ranging from subclinical infections to severe signs of multiorgan dysfunction. In Germany, laboratory confirmation of acute human infection is notifiable based on the Protection Against Infection Act. Disease or occurrence of the pathogen in pigs and sheep must be reported according to the regulation on reportable animal diseases. Transmission occurs via direct and indirect contact with the urine of infected animals, with rodents acting as the main reservoir. With an average annual incidence of 0.1 notified cases per 100,000 inhabitants, leptospirosis is a rare disease in Germany.This review article presents the current knowledge on leptospirosis in Germany in the framework of the project "Improving public health through a better understanding of the epidemiology of rodent-transmitted diseases" (RoBoPub) funded by the Ministry of Education and Research. In a One-Health approach, information about clinical manifestation, available prevalence data in humans and animals, knowledge of pathogen distribution, host association, mode of transmission, and survival in the environment is summarized. Preliminary findings on the influence of fluctuations in rodent populations on the occurrence of leptospirosis are also discussed. The aim of the article is to increase the awareness of this currently neglected disease in Germany.In future, higher temperatures and more frequent heavy rainfalls, which could occur due to climate change, should be taken into account.

Draining and liming of ponds as an effective measure for containment of CyHV-3 in carp farms.

Infections of common carp Cyprinus carpio and koi, its coloured morphotypes, with the cyprinid herpesvirus 3 (CyHV-3) can induce severe clinical signs and increased mortality in affected stocks. This may significantly challenge the economic basis of carp farming in Central Europe. To limit virus spread in carp farms, effective disinfection measures for ponds stocked with infected populations are required. In the traditional European pond aquaculture of carp, draining and liming of ponds with quicklime (CaO) up to pH 12 is a well-established disinfection measure against various pathogens. The present field study investigated whether these measures are sufficient for the inactivation of CyHV-3 infectivity in carp ponds. After draining and liming, the ponds were stocked with carp fry from a CyHV-3-negative stock, and 2 ponds were examined for the presence of CyHV-3-specific DNA sequences during the growth period of the carp and in the harvested stock. Wild fish (from the ponds, and feeder and drainage canals) and water samples (from the ponds) were also examined for CyHV-3-specific DNA sequences; and naïve carp were cohabited with wild fish, or exposed to the pondwater samples, to test for the presence of infectious virus. All examined samples remained negative for CyHV-3 throughout the study. This indicates that draining and liming with quicklime can be a suitable disinfection measure for ponds after a CyHV-3 outbreak in carp aquaculture.

Concentration of carp edema virus (CEV) DNA in koi tissues affected by koi sleepy disease (KSD).

Carp edema virus (CEV), the causative agent of 'koi sleepy disease' (KSD), appears to be spreading worldwide and to be responsible for losses in koi, ornamental varieties of the common carp Cyprinus carpio. Clinical signs of KSD include lethargic behaviour, swollen gills, sunken eyes and skin alterations and can easily be mistaken for other diseases, such as infection with cyprinid herpesvirus 3 (CyHV-3). To improve the future diagnosis of CEV infection and to provide a tool to better explore the relationship between viral load and clinical disease, we developed a specific quantitative PCR (qPCR) for strains of the virus known to infect koi carp. In samples from several clinically affected koi, CEV-specific DNA was present in a range from 1 to 2,046,000 copies, with a mean of 129,982 copies and a median of 45 copies per 250 ng of isolated DNA, but virus DNA could not be detected in all clinically affected koi. A comparison of the newly developed qPCR, which is based on a dual-labelled probe, to an existing end-point PCR procedure revealed higher specificity and sensitivity of the qPCR and demonstrated that the new protocol could improve CEV detection in koi. In addition to improved diagnosis, the newly developed qPCR test would be a useful research tool. For example, studies on the pathobiology of CEV could employ controlled infection experiments in which the development of clinical signs could be examined in parallel with a quantitative determination of virus load.

Another potential carp killer?: Carp Edema Virus disease in Germany.

BACKGROUND: Infections with carp edema virus, a pox virus, are known from Japanese koi populations since 1974. A characteristic clinical sign associated with this infection is lethargy and therefore the disease is called "koi sleepy disease". Diseased koi also show swollen gills, enophthalmus, and skin lesions. Mortality rates up to 80 % are described. For a long period of time, disease outbreaks seemed to be restricted to Japan. However, during the last years clinical outbreaks of koi sleepy disease also occurred in the UK and in the Netherlands. CASE PRESENTATION: In spring 2014 koi from different ponds showing lethargic behavior, skin ulcers, inflammation of the anus, enophthalmus, and gill necrosis were presented to the laboratory for diagnosis. In all cases, new koi had been purchased earlier that spring from the same retailer and introduced into existing populations. Eleven koi from six ponds were examined for ectoparasites and for bacterial and viral infections (cyprinid herpesviruses in general and especially koi herpesvirus (KHV) known formally as Cyprinid herpesvirus 3 (CyHV-3); and Carp Edema Virus). In most of the cases parasites were not detected from skin and gills. Only opportunistic freshwater bacteria were isolated from skin ulcers. In cell cultures no cytopathic effect was observed, and none of the samples gave positive results in PCR tests for cyprinid herpesviruses. By analyzing gill tissues for CEV in seven out of eleven samples by a nested PCR, PCR products of 547 bp and 180 bp (by using nested primers) could be amplified. An outbreak of Koi Sleepy Disease was confirmed by sequencing of the PCR products. These results confirm the presence of CEV in German koi populations. CONCLUSION: A clinical outbreak of "koi sleepy disease" due to an infection with Carp Edema Virus was confirmed for the first time in Germany. To avoid transmission of CEV to common carp testing of CEV should become part of fish disease surveillance programs.

Analysis of Yersinia ruckeri strains isolated from trout farms in northwest Germany.

Enteric redmouth disease (ERM), caused by Yersinia ruckeri, is among the most important infectious diseases in rainbow trout Oncorhynchus mykiss aquaculture in Europe. Our aim was to analyse the persistence of Y. ruckeri strains in trout farms in northwest Germany and their dissemination between farms based on a detailed molecular and phenotypical characterisation scheme. The data on identification and characterisation of Y. ruckeri strains and examining the distribution of these strains in the field could serve as a basis for preventive disease monitoring plans. During the observation period from June 2011 until June 2012, we collected 48 Y. ruckeri isolates from 12 different rainbow trout hatcheries. In total, 44 (91.7%) of the isolates were non-motile; in particular, all isolates recovered during the sampling period in winter and early spring were non-motile. In several trout farms, characteristic farm-specific Y. ruckeri isolates from particular typing groups were isolated throughout the year, while in other farms, which had a trading relationship between each other, ERM outbreaks were caused by Y. ruckeri from the same typing group. Our data indicate that in some farms, the causative Y. ruckeri strains persisted in the respective trout farm. The presence of Y. ruckeri from the same typing group in farms with a trading relationship indicates a dissemination of the infection between the farms.

Molecular analysis of Coxiella burnetii in Germany reveals evolution of unique clonal clusters.

The causative agent of Q fever, Coxiella burnetii, is a query agent occurring naturally all over the world. We studied 104 German Coxiella burnetii strains/DNA samples obtained between 1969 and 2011 using a 14 microsatellite marker Multiple-locus variable-number of tandem repeat (VNTR) analysis (MLVA) technique. We were able to divide our collection into 32 different genotypes clustered into four major groups (A-D). Two of these (A and C) formed predominant clonal complexes that covered 97% of all studied samples. Group C consisted exclusively of cattle-associated isolates/DNA specimens, while group A comprised all other affected species including all sheep-derived strains/DNA samples. Within this second cluster, two major genotypes (A1, A2) were identified. Genotype A2 occurred in strains isolated from ewes in northern and central Germany, whereas genotype A1 was found in most areas of Germany. MLVA analysis of C. burnetii strains from neighbouring countries revealed a close relationship to German strains. We thus hypothesize that there is a western and central European cluster of C. burnetii. We identified predominant genotypes related to relevant host species and geographic regions which is in line with findings of the Dutch Q fever outbreak (2007-2010). Furthermore three of our analyzed German strains are closely related to the Dutch outbreak clone. These findings support the theory of predominant genotypes in the context of regional outbreaks. Our results show that a combination of 8 MLVA markers provides the highest discriminatory power for attributing C. burnetii isolates to genotypes. For future epidemiological studies we propose the use of three MLVA markers for easy and rapid classification of C. burnetii into 4 main clusters.

Detection of Coxiella burnetii in the mammary gland of a dairy goat.

The zoonotic bacterium Coxiella (C.) burnetii can be excreted by infected goats through birth products and milk. The detection of C. burnetii DNA in the mammary gland tissue of infected dairy goats and intermittent milk shedders has been reported, but confirmation of C. burnetii bacteria in the udder remained pending. The pathogen caused abortions in a 152-head dairy goat herd, resulting in the vaccination against C. burnetii of the entire herd with annual boosters. To monitor the C. burnetii shedding at herd level, monthly bulk tank milk (BTM) samples were analyzed using PCR (IS1111). Despite vaccination, C. burnetii DNA was detected in BTM samples within the first 16 months of the study. Therefore, individual milk samples were tested on four different occasions several months apart to identify potential intermittent milk shedders. Only one goat (#67455) tested positive three times. This goat was necropsied to investigate the presence of C. burnetii in the udder and other organs. PCR detected C. burnetii DNA solely in both mammary glands and the left teat cistern. Immunohistological examination identified C. burnetii antigen in mammary gland tissue, confirmed by the detection of C. burnetii bacteria in the mammary epithelial cells using fluorescence in situ hybridization. The removal of goat #67455 led to negative BTM samples until the end of the study. The findings demonstrate the occurrence of C. burnetii in the mammary gland of a naturally infected and vaccinated goat. The presence possibly contributed to intermittent milk shedding of goat #67455, and the mammary gland tissue may serve as a replicative niche for C. burnetii.

Control of Coxiella burnetii shedding in a dairy goat herd by annual offspring vaccination.

A Coxiella burnetii vaccination program, targeting only doelings, was introduced on a German goat farm to curb bacterial shedding. In 2018, adults were vaccinated with a C. burnetii Phase I vaccine at three-weeks apart following pathogen diagnosis, with a booster administered six months later due to sustained high shedding. From 2018 to 2021, doelings received two vaccine doses without any further boosters. To assess the program's efficacy, vaginal swabs from up to 40 animals per age group were collected during kidding seasons from 2019 to 2022. Bulk tank milk (BTM) samples were gathered monthly from January 2018 to October 2022 to monitor herd-level shedding. Real-time PCR analysis determined genome equivalents in all three sample types. Serum samples were taken before the initial immunization and during the post-kidding season from up to 40 goats per age group annually from 2018 to 2022. Phase-specific ELISAs determined IgG Phase I and Phase II antibodies. Additionally, two serum samples per age group from 2022 were analyzed using a neutralization assay. A few goats continued shedding small quantities during subsequent kidding seasons. Although positive BTM samples decreased, they displayed an undulating trend. Most age groups exhibited robust IgG Phase I responses and lower IgG Phase II levels post immunization. Mean IgG levels remained elevated until the study ended compared to pre-vaccination levels in most age groups. Additionally, neutralizing antibodies were present regardless of IgG response. Overall, double vaccination induced lasting antibody levels, but did not entirely prevent C. burnetii shedding. The resilience of the observed humoral immune activity requires further investigation.

German Francisella tularensis isolates from European brown hares (Lepus europaeus) reveal genetic and phenotypic diversity.

BACKGROUND: Tularemia is a zoonotic disease caused by Francisella tularensis that has been found in many different vertebrates. In Germany most human infections are caused by contact with infected European brown hares (Lepus europaeus). The aim of this study was to elucidate the epidemiology of tularemia in hares using phenotypic and genotypic characteristics of F. tularensis. RESULTS: Cultivation of F. tularensis subsp. holarctica bacteria from organ material was successful in 31 of 52 hares that had a positive PCR result targeting the Ft-M19 locus. 17 isolates were sensitive to erythromycin and 14 were resistant. Analysis of VNTR loci (Ft-M3, Ft-M6 and Ft-M24), INDELs (Ftind33, Ftind38, Ftind49, RD23) and SNPs (B.17, B.18, B.19, and B.20) was shown to be useful to investigate the genetic relatedness of Francisella strains in this set of strains. The 14 erythromycin resistant isolates were assigned to clade B.I, and 16 erythromycin sensitive isolates to clade B.IV and one isolate was found to belong to clade B.II. MALDI-TOF mass spectrometry (MS) was useful to discriminate strains to the subspecies level. CONCLUSIONS: F. tularensis seems to be a re-emerging pathogen in Germany. The pathogen can easily be identified using PCR assays. Isolates can also be identified within one hour using MALDI-TOF MS in laboratories where specific PCR assays are not established. Further analysis of strains requires genotyping tools. The results from this study indicate a geographical segregation of the phylogenetic clade B.I and B.IV, where B.I strains localize primarily within eastern Germany and B.IV strains within western Germany. This phylogeographical pattern coincides with the distribution of biovar I (erythromycin sensitive) and biovar II (erythromycin resistance) strains. When time and costs are limiting parameters small numbers of isolates can be analysed using PCR assays combined with DNA sequencing with a focus on genetic loci that are most likely discriminatory among strains found in a specific area. In perspective, whole genome data will have to be investigated especially when terrorist attack strains need to be tracked to their genetic and geographical sources.

Biochemical and molecular heterogeneity among isolates of Yersinia ruckeri from rainbow trout (Oncorhynchus mykiss, Walbaum) in North West Germany.

BACKGROUND: Enteric Redmouth Disease (ERM), caused by Yersinia ruckeri, is one of the most important infectious diseases in rainbow trout (Oncorhynchus mykiss) aquaculture in Europe. More recently, non-motile vaccine resistant isolates appear to have evolved and are causing disease problems throughout Europe, including Germany. The aim of this study was to analyse the variation of biochemical and molecular characteristics of Y. ruckeri isolates collected in north west Germany as a basis for strain differentiation. The isolates originated mainly from rainbow trout and were characterised by biochemical profiling, 16S rDNA sequencing, repetitive sequence-based PCRs, including (GTG)5-PCR, BOX-PCR, ERIC-PCR and REP-PCR, and pulsed-field gel electrophoresis (PFGE). RESULTS: In total, 83 isolates were characterised, including 48 isolates collected during a field study in north west Germany. All isolates were confirmed as Y. ruckeri by the API 20E system. Five isolates were additionally confirmed as Y. ruckeri by Y. ruckeri-specific PCR and 16S rDNA sequencing. Only 17 isolates hydrolyzed Tween 80/20. Sixty-six isolates (79.5%) were non-motile. Two different patterns were obtained by REP-PCR, five patterns by ERIC-PCR, four patterns by (GTG)5-PCR and three patterns by BOX-PCR. NotI-directed PFGE resulted in 17 patterns that differed from each other by 25-29 fragments. Isolates from the field study clustered together as PFGE type C. According to the results of API 20E, repetitive sequence-based PCRs and PFGE, these isolates could be subdivided into 27 different groups. CONCLUSIONS: The detailed molecular and phenotypic characterisation scheme developed in this study could be used to help trace the dissemination of Y. ruckeri isolates, and thus may represent part of improved disease monitoring plans in the future.

Co-exposure to Anaplasma spp., Coxiella burnetii and tick-borne encephalitis virus in sheep in southern Germany.

The intracellular bacteria Anaplasma spp. and Coxiella burnetii and the tick-borne encephalitis virus (TBEV) are tick-transmitted pathogens circulating in the southern German sheep population. Knowledge of interaction among Anaplasma spp., C. burnetii and TBEV in sheep is lacking, but together they might promote and reinforce disease progression. The current study aimed to identify co-exposure of sheep to Anaplasma spp., C. burnetii and TBEV. For this purpose, 1,406 serum samples from 36 sheep flocks located in both southern German federal states, Baden-Wuerttemberg and Bavaria, were analysed by ELISAs to determine the antibody levels of the three pathogens. Inconclusive and positive results from the TBEV ELISA were additionally confirmed by a serum neutralisation assay. The proportion of sheep with antibodies against Anaplasma spp. (47.2%), C. burnetii (3.7%) and TBEV (4.7%) differed significantly. Significantly more flocks with Anaplasma spp. seropositive sheep (91.7%) were detected than flocks with antibodies against TBEV (58.3%) and C. burnetii (41.7%), but there was no significant difference between the number of flocks which contained TBEV and C. burnetii seropositive sheep. Seropositivity against at least two pathogens was detected in 4.7% of sheep from 20 flocks. Most co-exposed sheep had antibodies against Anaplasma spp./TBEV (n = 36), followed by Anaplasma spp./C. burnetii (n = 27) and Anaplasma spp./C. burnetii/TBEV (n = 2). Only one sheep showed an immune response against C. burnetii and TBEV. Flocks with sheep being positive against more than one pathogen were widely distributed throughout southern Germany. The descriptive analysis revealed no association between the antibody response of the three pathogens at animal level. Taking the flocks as a cluster variable into account, the exposure to TBEV reduced the probability of identifying C. burnetii antibodies in sheep significantly (odds ratio 0.46; 95% confidence interval 0.24-0.85), but the reason for this is unknown. The presence of Anaplasma spp. antibodies did not influence the detection of antibodies against C. burnetii and TBEV. Studies under controlled conditions are necessary to evaluate any possible adverse impact of co-exposure to tick-borne pathogens on sheep health. This can help to clarify rare disease patterns. Research in this field may also support the One Health approach due to the zoonotic potential of Anaplasma spp., C. burnetii and TBEV.

Investigation and response to a large outbreak of leptospirosis in field workers in Lower Saxony, Germany.

Between June and August 2014, 45 cases of leptospirosis were notified among workers on two strawberry farms in North-West Germany. We describe the characteristics of the outbreak and the actions taken to prevent further cases. The activities of the local, federal and national public health and veterinary authorities included collection of case data, laboratory testing of human specimens and of small mammals trapped on the fields, investigation of weather data, as well as information provided to farmers, field workers, physicians and to the authorities in Poland and Romania. Of the 45 identified cases (median age 22, 60% male), 47% were hospitalized. Characteristic symptoms were fever ≥38.5°C, generalized muscle pain and an increase in renal or liver enzymes. Thirteen cases were laboratory confirmed by serological and/or molecular methods. ELISA tests for Leptospira IgG and IgM-antibodies were positive in those samples taken >5 days after hospitalization. The probable causative agent was identified as Leptospira kirschneri serovar Grippotyphosa. Leptospira-specific DNA was found in kidneys of 67% of 64 trapped small mammals and was further identified as Leptospira kirschneri multi locus sequence type 110. During the estimated time period of human infections, the affected region faced warm weather with heavy rainfalls. The results of this investigation are in accordance with the theory of a chain of infection from mice to field workers during warm and humid weather. In 2015, a campaign was initiated to inform physicians, farmers and workers to enhance prevention measures, such as the use of personal protective equipment and early consultation of physicians in case of illness. Since then, no further outbreak occurred.

Two Years after Coxiella burnetii Detection: Pathogen Shedding and Phase-Specific Antibody Response in Three Dairy Goat Herds.

The infection dynamics of Coxiella (C.) burnetii were investigated in three dairy goat herds (A, B, and C) 2 years after the first pathogen detection. A total of 28 and 29 goats from herds A and B, and 35 goats from herd C, were examined. Sera were analyzed on three sampling dates using phase-specific serology. Pathogen shedding was assessed using post-partum vaginal swabs and monthly bulk tank milk (BTM) samples. Dust samples from a barn and milking parlor were also collected monthly. These samples were analyzed with PCR (target IS1111). In herd A, individual animals tested seropositive, while vaginal swabs, BTM, and most dust samples tested negative. Herds B and C exhibited high IgG phase I activity, indicating a past infection. In herd B, approximately two-thirds of the goats shed C. burnetii with vaginal mucus, and irregular positive results were obtained from BTM. Herd C had two positive goats based on vaginal swabs, and BTM tested positive once. Dust samples from herds B and C contained C. burnetii DNA, with higher quantities typically found in samples from the milking parlor. This study highlights the different infection dynamics in three unvaccinated dairy goat herds and the potential use of dust samples as a supportive tool to detect C. burnetii at the herd level.

Surveillance of Coxiella burnetii Shedding in Three Naturally Infected Dairy Goat Herds after Vaccination, Focusing on Bulk Tank Milk and Dust Swabs.

Q fever outbreaks on three dairy goat farms (A-C) were monitored after the animals had been vaccinated with an inactivated Coxiella burnetii phase I vaccine. The antibody response was measured before vaccination by serum samples with two C. burnetii phase-specific ELISAs to characterize the disease status. Shedding was determined by vaginal swabs during three kidding seasons and monthly bulk tank milk (BTM) samples. Dust swabs from one windowsill of each barn and from the milking parlors were collected monthly to evaluate the indoor exposure. These samples were analyzed by qPCR. The phase-specific serology revealed an acute Q fever infection in herd A, whereas herds B and C had an ongoing and past infection, respectively. In all three herds, vaginal shedders were present during three kidding seasons. In total, 50%, 69%, and 15% of all collected BTM samples were C. burnetii positive in herds A, B, and C, respectively. Barn dust contained C. burnetii DNA in 71%, 45%, and 50% of examined swabs collected from farms A, B, and C, respectively. The largest number of C. burnetii positive samples was obtained from the milking parlor (A: 91%, B: 72%, C: 73%), indicating a high risk for humans to acquire Q fever during milking activity.

Impact of Coxiella burnetii vaccination on humoral immune response, vaginal shedding, and lamb mortality in naturally pre-infected sheep.

Introduction: Sheep are considered to be one of the main reservoirs for Coxiella burnetii, a gram-negative bacterium with high zoonotic potential. Infected sheep shed tremendous amounts of the pathogen through birth products which caused human Q fever epidemics in several countries. Information about the impact of an inactivated C. burnetii Phase I vaccine on humoral immune response, vaginal shedding, and lamb mortality in naturally pre-infected sheep is scarce. Methods: Two identically managed and naturally C. burnetii-infected sheep flocks were examined for two lambing seasons (2019 and 2020). One flock (VAC) received a primary vaccination against Q fever before mating and the second flock served as control (CTR). In each flock, one cohort of 100 ewes was included in follow-up investigations. Serum samples at eight different sampling dates were analyzed by C. burnetii phase-specific ELISAs to differentiate between the IgG Phase I and II responses. Vaginal swabs were collected within three days after parturition and examined by a C. burnetii real-time PCR (IS1111). Lamb losses were recorded to calculate lamb mortality parameters. Results: After primary vaccination, almost all animals from cohort VAC showed a high IgG Phase I response up until the end of the study period. In cohort CTR, the seropositivity rate varied from 35.1% to 66.3%, and the Phase I and Phase II pattern showed an undulating trend with higher IgG Phase II activity during both lambing seasons. The number of vaginal shedders was significantly reduced in cohort VAC compared to cohort CTR during the lambing season in 2019 (p < 0.0167). There was no significant difference of vaginal shedders in 2020. The total lamb losses were low in both cohorts during the two investigated lambing seasons (VAC 2019: 6.8%, 2020: 3.2%; CTR 2019: 1.4%, 2020: 2.7%). Discussion: Neither the C. burnetii vaccine nor the C. burnetii infection seem to have an impact on lamb mortality. Taken together, the inactivated C. burnetii Phase I vaccine induced a strong IgG Phase I antibody response in naturally pre-infected sheep. It might also reduce vaginal shedding in the short term but seems to have little beneficial impact on lamb mortality.

Cluster of human Puumala orthohantavirus infections due to indoor exposure?-An interdisciplinary outbreak investigation.

Puumala orthohantavirus (PUUV) is the most important hantavirus species in Europe, causing the majority of human hantavirus disease cases. In central and western Europe, the occurrence of human infections is mainly driven by bank vole population dynamics influenced by beech mast. In Germany, hantavirus epidemic years are observed in 2- to 5-year intervals. Many of the human infections are recorded in summer and early autumn, coinciding with peaks in bank vole populations. Here, we describe a molecular epidemiological investigation in a small company with eight employees of whom five contracted hantavirus infections in late 2017. Standardized interviews with employees were conducted to assess the circumstances under which the disease cluster occurred, how the employees were exposed and which counteractive measures were taken. Initially, two employees were admitted to hospital and serologically diagnosed with hantavirus infection. Subsequently, further investigations were conducted. By means of a self-administered questionnaire, three additional symptomatic cases could be identified. The hospital patients' sera were investigated and revealed in one patient a partial PUUV L segment sequence, which was identical to PUUV sequences from several bank voles collected in close proximity to company buildings. This investigation highlights the importance of a One Health approach that combines efforts from human and veterinary medicine, ecology and public health to reveal the origin of hantavirus disease clusters.