Leprosy in squirrels: an ancient disease in an endangered wildlife host

Leprosy is an ancient human disease that was thought to have been eradicated from the British Isles. The last case of autochthonous human infection was documented in the 1950’s. Natural infection with leprosy bacilli in species other than humans was first described in ninebanded armadillos in the 1970s in the United States of America. Recently, both bacterial species causing leprosy, Mycobacterium leprae and Mycobacterium lepromatosis, were isolated from Eurasian red squirrels (Sciurus vulgaris, ERS) across the British Isles. ERS are endangered in this part of their range, and efforts are made for their protection. This thesis offers insight into important aspects (clinical presentation, pathology, epidemiology) of the basic description of leprosy in live ERS, based on data from two wild British island ERS populations naturally infected with leprosy bacilli. The populations, one in Scotland and one in England, were studied for 18 and 24 months respectively, with live sampling taking place every six months. Additionally, samples from ERS, Eastern grey squirrels (Sciurus carolinensis, GS) and Pallas’s squirrels (Callosciurus erythraeus, PS) were obtained from Britain (ERS, GS), Germany (ERS, PS) and Italy (ERS, GS, PS) and screened for the presence of leprosy bacilli to provide new epidemiological surveillance information on squirrel leprosy. Established, adapted, and novel tests were used to diagnose leprosy in squirrels. Accurate clinical diagnosis is important to identify populations affected by the disease. Serological methods were useful to confirm the clinical diagnosis. Molecular methods were the only way to identify leprosy bacilli in squirrels without clinical signs of disease. A diagnostic decision tree is proposed to allow optimised, consistent use of the methods now available depending on the situation in which a diagnosis is sought. ERS that are infected with M. leprae and develop clinical leprosy usually showed a multibacillary, lepromatous or borderline lepromatous form of the disease. Lepromatous leprosy is characterised by an inability of the host immune response to control bacterial replication and dissemination. Leprosy in ERS progressed slowly, and the intensity of lesions could easily be separated into four categories from mild to severe based on lesion size, structural characteristics and the presence or absence of ulceration. Several months passed between the time when the bacteria first became detectable in an ERS tissues and the onset of clinical disease. Clinical disease then progressed on varying timescales in different individuals, but usually allowed the individuals to thrive for long time frames (months – years). The maximum time period a clinically diseased ERS was followed in this study was 18 months. Prevalence and morbidity differed in individual ERS populations. In one population the total apparent two-year prevalence of leprosy was 36% with a morbidity rate of 22% for the same population and timeframe. In the other the apparent two-year prevalence was only 4% and no clinical cases of leprosy were observed. The presence of leprosy did not have a negative effect on individual ERS or whole populations that could be measured using health indicators such as body condition, weight, general health and ectoparasite burdens. As part of this study, M. leprae was identified in ERS in two new locations within the UK, but not in British GS or any squirrel species in Germany or Italy. The results indicate that leprosy alone is unlikely to be a major factor contributing to ERS mortalities and thus may not be of great conservation concern in this species. Continued research into ERS leprosy in natural systems could provide valuable insight into disease dynamics that may benefit humans and other hosts in a One Health and conservation medicine framework

Schaf- und Ziegenhaltung in der Tiergestützten Intervention

Schafe und Ziegen werden regelmäßig im Rahmen tiergestützter Interventionen (TGI) eingesetzt. Obwohl tiergestützt arbeitende Projekte in Deutschland seit langem existieren, wurde erst durch die in den letzten Jahren angestrebte Professionalisierung dieses Arbeitsfeldes deutlich, wie wenig Informationen über diese Nutzungsform bisher vorhanden sind, die z.B. von den veterinärmedizinischen Überwachungsbehörden oder Praktikern genutzt werden können. Daher soll diese Arbeit darstellen, warum eine Haltung von Schafen und Ziegen in der TGI sinnvoll ist, wie sich solche Haltung und Nutzung aktuell gestaltet, ob sie die Tiere in besonderem Maße belastet, ob Maßnahmen zum Schutz der öffentlichen Gesundheit nötig sind und ob die rechtliche Einordnung der Einrichtungen geeignet ist, das Wohlbefinden der Tiere zu schützen. Zu diesem Zweck wurde zunächst die Relevanz und rechtliche Stellung tiergestützter Arbeit mit Schafen und Ziegen anhand der zum Thema vorhandenen Literatur erarbeitet. Im Folgenden wurden neun Jugendfarmen und Aktivspielplätze in Bayern und Baden-Württemberg besucht (insgesamt 25 Schafe, 32 Ziegen), um durch die Beantwortung eines Fragebogens und eigene Beobachtungen vor Ort einen Eindruck von der ‚Arbeit‘ und Haltung der Tiere in den Einrichtungen zu gewinnen. Um festzustellen, ob Einsatz oder Haltungspraxis die Tiere belasten, wurden der allgemeine Gesundheitszustand und parasitologische Status der Tiere, ihr Grund- und Sozialverhalten und dessen Beeinflussung durch die Anwesenheit von Personen (Direktbeobachtungen), ihr Verhalten gegenüber dem Menschen (Direktbeob-achtungen, Reaktionsproben) sowie ihre Herzfrequenz und Herzratenvariabilität und die Kotkortisolmetabolitenkonzentration über 24-Stunden erfasst. Untersuchungen auf potentielle Zoonoseerreger lieferten Informationen zur Reservoirfunktion der Tiere. Die Schafe und Ziegen werden in den Einrichtungen vorwiegend passiv genutzt. Durch die Übernahme von Verantwortung bei ihrer Versorgung sollen Kinder und Jugendliche im urbanen Umfeld in ihrer Entwicklung gefördert werden, Erfahrungen mit Nutztieren machen und den Tierschutzgedanken verinnerlichen. Die gemeinnützigen Nutztierhaltungen fallen nicht unter die Erlaubnis- und Sachkundepflicht nach §11 TierSchG, sondern unterliegen nur der Beaufsichtigung nach §16 TierSchG. Die besuchten Haltungen sind überwiegend als tiergerecht zu bezeichnen. Die Tiere zeigten keine Verhaltensstörungen und artgemäßes Grundverhalten (z.B. Wiederkauzeit/24-Stunden: Ziegen im Mittel 7 ¾ Stunden, Schafe 9 Stunden). Direkte Personenkontakte waren in allen Einrichtungen deutlich seltener als erwartet (ca. 2 Stunden/Öffnungstag direkter Mensch-Tier-Kontakt möglich). Die Anwesenheit von Personen führte zu keiner signifikanten Zunahme antagonistischer Interaktionen. Der überwiegende Teil der Tiere zeigt eine neutrale bis positive Einstellung gegenüber dem Menschen (z.B. Voluntary-Approach-Test: Annäherung 42,1% der Tiere; sich nicht nähernde Tiere: 24,2% ängstlich, 75,8% desinteressiert). Die Ergebnisse der Kotkortisolmetabolitenbestimmungen stützen die in den Verhaltensbeobachtungen gewonnenen Erkenntnisse. Im Median lag die Kotkortisolmetabolitenkonzentration über 24 Stunden bei Ziegen bei 267 ng/g, bei Schafen bei 244 ng/g. Während der Öffnungszeiten (zusätzliche Bewegungs-möglichkeiten, min. 1 Fütterung) lagen die Werte signifikant höher als vor der Öffnung (Ziegen: 256 ng/g bzw. 353 ng/g, p = 0,003; Schafe: 224 ng/g bzw. 281 ng/g, p = 0,016). Insgesamt ergaben sich keine eindeutigen Hinweise auf eine besondere Belastung. STEC wurden sehr häufig nachgewiesen (Schafe: 100%; Ziegen: 89,3%). Während weder Salmonella spp. noch Coxiella burnetii gefunden wurden, gelang der Nachweis von Staphylococcus spp. bei jeweils 75% der Tiere. Ein Anteil von 25% der Schafe bzw. 14,3% der Ziegen erwiesen sich als Träger von Campylobacter spp. Beide Tierarten sind somit Reservoir für potentielle Zoonoseerreger. Aus den Untersuchungen ist zu schließen, dass für die tiergestützte Arbeit mit Schafen und Ziegen ein gesonderter rechtlicher Rahmen (Betreuungsverträge, Kennzeichnung) sinnvoll ist. Die Art der Nutzung und Haltung der kleinen Wiederkäuer gefährdet das Wohlbefinden der Tiere nicht grundsätzlich und kann neben den förderlichen Effekten für den Menschen zu einer Verbesserung der Stellung von Nutztieren in der Gesellschaft führen. Die Auswahl der Schafe und Ziegen für eine TGI muss das artspezifische und individuelle Verhalten beachten, um ihre Eignung für den angestrebten Einsatz zu gewährleisten. Eine Sensibilisierung tiergestützt Arbeitender für die Thematik Zoonosen und die Implementierung betriebsindividueller Hygiene- und Impfkonzepte ist sinnvoll

Wildlife Disease Monitoring:Methods and Perspectives

In the last few decades, scientific interest in wildlife diseases has steadily grown and has recently been boosted by the SARS-CoV-2 pandemic, which highlighted that the health of humans, livestock, wildlife and, ultimately, of the whole environment is inextricably linked [...

Detection of humoral immunity to mycobacteria causing leprosy in Eurasian red squirrels (Sciurus vulgaris) using a quantitative rapid test

Cancer Signaling networks and Molecular Therapeutic

British Red Squirrels Remain the Only Known Wild Rodent Host for Leprosy Bacilli

<p>Eurasian red squirrels (Sciurus vulgaris) in the British Isles are the most recently discovered animal reservoir for the leprosy bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Initial data suggest that prevalence of leprosy infection is variable and often low in different squirrel populations. Nothing is known about the presence of leprosy bacilli in other wild squirrel species despite two others (Siberian chipmunk [Tamias sibiricus], and Thirteen-lined ground squirrel [Ictidomys tridecemlineatus]) having been reported to be susceptible to experimental infection with M. leprae. Rats, a food-source in some countries where human leprosy occurs, have been suggested as potential reservoirs for leprosy bacilli, but no evidence supporting this hypothesis is currently available. We screened 301 squirrel samples covering four species [96 Eurasian red squirrels, 67 Eastern gray squirrels (Sciurus carolinensis), 35 Siberian chipmunks, and 103 Pallas's squirrels (Callosciurus erythraeus)] from Europe and 72 Mexican white-throated woodrats (Neotoma albigula) for the presence of M. leprae and M. lepromatosis using validated PCR protocols. No DNA from leprosy bacilli was detected in any of the samples tested. Given our sample-size, the pathogen should have been detected if the prevalence and/or bacillary load in the populations investigated were similar to those found for British red squirrels.</p

Atrial fibrillation genetic risk differentiates cardioembolic stroke from other stroke subtypes

AbstractObjectiveWe sought to assess whether genetic risk factors for atrial fibrillation can explain cardioembolic stroke risk.MethodsWe evaluated genetic correlations between a prior genetic study of AF and AF in the presence of cardioembolic stroke using genome-wide genotypes from the Stroke Genetics Network (N = 3,190 AF cases, 3,000 cardioembolic stroke cases, and 28,026 referents). We tested whether a previously-validated AF polygenic risk score (PRS) associated with cardioembolic and other stroke subtypes after accounting for AF clinical risk factors.ResultsWe observed strong correlation between previously reported genetic risk for AF, AF in the presence of stroke, and cardioembolic stroke (Pearson’s r=0.77 and 0.76, respectively, across SNPs with p &lt; 4.4 × 10−4 in the prior AF meta-analysis). An AF PRS, adjusted for clinical AF risk factors, was associated with cardioembolic stroke (odds ratio (OR) per standard deviation (sd) = 1.40, p = 1.45×10−48), explaining ∼20% of the heritable component of cardioembolic stroke risk. The AF PRS was also associated with stroke of undetermined cause (OR per sd = 1.07, p = 0.004), but no other primary stroke subtypes (all p &gt; 0.1).ConclusionsGenetic risk for AF is associated with cardioembolic stroke, independent of clinical risk factors. Studies are warranted to determine whether AF genetic risk can serve as a biomarker for strokes caused by AF.</jats:sec

A Review of Non-Invasive Sampling in Wildlife Disease and Health Research:What's New?

SIMPLE SUMMARY: The interest in wildlife research has increased in the last decades as more scientists work within a One Health framework that regards human, livestock and wildlife health as connected entities. To minimise the impact of research on wildlife, collecting samples with as little disturbance of the animals as possible is important. In our review, we assess the use of so-called non-invasive sampling and summarise which samples can be used successfully when carrying out research on wildlife diseases and health status. Our results show that interest in minimally invasive sampling has steadily increased since the 2010s. Topics able to employ these methods include disease research, but also stress and other hormone assessments, pollution studies, and dietary studies. At the moment, such methods are mainly used to collect samples from land mammals, however, they can also be used in a wide range of other animals. Ever more capable analytical methods will allow for an even wider use of such “animal-friendly” sampling methods. ABSTRACT: In the last decades, wildlife diseases and the health status of animal populations have gained increasing attention from the scientific community as part of a One Health framework. Furthermore, the need for non-invasive sampling methods with a minimal impact on wildlife has become paramount in complying with modern ethical standards and regulations, and to collect high-quality and unbiased data. We analysed the publication trends on non-invasive sampling in wildlife health and disease research and offer a comprehensive review on the different samples that can be collected non-invasively. We retrieved 272 articles spanning from 1998 to 2021, with a rapid increase in number from 2010. Thirty-nine percent of the papers were focussed on diseases, 58% on other health-related topics, and 3% on both. Stress and other physiological parameters were the most addressed research topics, followed by viruses, helminths, and bacterial infections. Terrestrial mammals accounted for 75% of all publications, and faeces were the most widely used sample. Our review of the sampling materials and collection methods highlights that, although the use of some types of samples for specific applications is now consolidated, others are perhaps still underutilised and new technologies may offer future opportunities for an even wider use of non-invasively collected samples

CLINICAL PROGRESSION OF LEPROSY IN EURASIAN RED SQUIRRELS (SCIURUS VULGARIS) IN A NATURALLY INFECTED WILD POPULATION

Leprosy has been described in Eurasian red squirrel (Sciurus vulgaris; ERS) carcasses since 2014. Studies of ERS carcasses have not provided information about incubation or disease progression in this host but have provided important insights into pathogen presence and distribution throughout the United Kingdom. Here we present field study data on 31 live ERS from an island population naturally infected with Mycobacterium leprae that were assessed longitudinally over a 2-yr time period. Clinical assessment, serologic (anti-phenolic glycolipid-I antibody [αPGL-I] detection) and molecular methods (polymerase chain reaction) were used to diagnose and categorize ERS at each assessment as a leprosy case, a leprosy suspect, colonized by M. leprae, or a contact ERS. Eight ERS (25.8%) were identified as leprosy cases: four at initial assessment, two at 6 mon and two at 24 mon after initial assessment. One ERS was categorized a leprosy suspect when it developed typical lesions 12 mon after initial assessment, despite negative serologic and molecular test results at this time, though M. leprae DNA had been isolated during the initial assessment. Seven ERS (22.6%) were categorized as colonized and of these, six were reassessed but did not develop clinical signs of leprosy within 6 (n = 2), 12 (n = 3), and 18 (n = 1) mon. Most (48.4%, n = 15) were categorized as contact ERS. Progression of leprosy lesions varied between ERS, but always increased in severity over time and was paralleled with increased antibody response. Based on our dataset, we propose the hypotheses: 1) leprosy in ERS is a chronic, slowly progressing disease in this species, similar to that described for other hosts; 2) lesions can undergo repeated ulceration-healing cycles; and 3) in some instances M. leprae DNA and αPGL-I antibodies are detectable before the onset of clinical signs of disease. Future studies addressing the progression of leprosy in ERS should follow affected animals over a longer time period and include tissue samples to pair molecular diagnostics with serologic results