Clinical outcome and diagnostic methods of atypical mycobacteriosis due to Mycobacterium avium ssp. hominissuis in a group of captive lowland tapirs (Tapirus terrestris)

Detection of non-tuberculous mycobacteria in native wildlife species at conservation risk of Argentina

Introduction

Non-tuberculous Mycobacteria (NTM) are mainly environmental but can cause opportunistic infections and diseases in humans and animals. Livestock and wild animals can be infected with NTM. In Argentina, there are native wild species facing conservation risks, and they are the focus of protection and reintroduction projects designed to preserve biodiversity in various ecoregions. The aim of this study was to report the presence of NTM in samples collected from four endangered native wild species from nine Argentine provinces, as part of their pre-release health assessment.

Methods

A total of 165 samples from giant anteater, peccary, tapir and pampas deer were obtained, these included either bronchoalveolar or endotracheal lavages, or oropharyngeal, nasopharyngeal or tracheal swabs. Bacteriological culture followed by molecular identification and sequencing were performed.

Results

A total of 27 NTM were detected, including Mycobacterium avium subsp. hominissuis, M. intracellulare, M. terrae, M. gordonense, M. kumamotonense, M. fortuitum, M. saskatchewanense, and M. genavense. Results revealed a 16,36% NTM recovery rate, with the giant anteater showing the highest prevalence among the mammals under study.

Discussion

In Argentina, due to extensive production systems, the interaction between domestic and wild species sharing the same environment is frequent, increasing the exposure of all the species to these NTM. In this way, the transmission of infectious agents from one to another is feasible. Moreover, NTMs might interfere with the diagnosis of bovine tuberculosis and paratuberculosis. These findings emphasize the importance of active health surveillance in conservation programs. It highlights the need to address NTM epidemiology in wildlife and its impact on conservation and public health.

Environmental Sources and Transmission of Nontuberculous Mycobacteria

The field of environmental nontuberculous mycobacteria (NTM) is benefiting from a new era of genomics that has catapulted our understanding of preferred niches, transmission, and outbreak investigations. The ability to forecast environmental features that promote or reduce environmental NTM prevalence will greatly improve with coordinated environmental sampling and by elevating the necessity for uniform disease notifications. Studies that synergize environmental biology, isolate notifications, and comparative genomics in prospective, longitudinal studies, particularly during climate changes and weather events, will be useful to solve longstanding NTM public health quandaries.

Challenging diagnosis and successful treatment of localised Mycobacterium avium subsp. hominissuis glossitis in a dog on long-term immunomodulatory therapy

CASE HISTORY

A 3-year-old, intact female mixed-breed dog, weighing 7 kg, was presented with generalised swelling of the tongue, leading to impaired deglutition and episodes of dyspnoea. From the age of 2 years the dog had been under immunosuppressive therapy due to atopic dermatitis.

CLINICAL FINDINGS AND TREATMENT

Multiple nodular lesions at the apex of the tongue were noted as well as mandibular and retropharyngeal lymph node enlargement. Serum biochemistry results showed inflammatory changes. The results of several biopsies taken over 7 months indicated persistent pyogranulomatous and necrotising glossitis despite ongoing antimicrobial treatment with first amoxicillin/clavulanic acid and then pradofloxacin. No foreign material, acid-fast bacteria or fungal hyphae were detected throughout. The final diagnosis of Mycobacterium avium subsp. hominissuis (Mah) was reached after PCR and bacterial culture were carried out on the third biopsy sample. Therapy was initiated with rifampicin, clarithromycin and doxycycline, leading to complete remission of the lesions.

DIAGNOSIS

Severe chronic pyogranulomatous and necrotising glossitis associated with infection by Mah.

CLINICAL RELEVANCE

This report describes challenges in the diagnosis and therapy of a localised Mah infection in an iatrogenically immunocompromised dog. Successful treatment was only achieved with a specific combination of antibiotics administered long-term.

Health Status of Bycaught Common Eiders (Somateria mollissima) from the Western Baltic Sea

Simple Summary

We performed post-mortem investigations of 121 Common Eiders (Somateria mollissima), which were incidentally caught in fishing gear from 2017 to 2019 in Denmark. The aim of the study was to obtain an overview of health issues and pathogens occurring in the population of these birds. The European population of the Common Eider is endangered, but the reasons for the decline of the population have not yet been determined. In times of accelerating species loss, it is important to determine factors that impact population numbers of declining species. The post-mortem investigations included biometric measurements and determination of age, sex and nutritional status, as well as parasitological, bacteriological and virological investigations. The majority of Common Eiders had a good or moderate nutritional status. Most animals were infected with intestinal parasites, and we commonly found inflammation in organs like the liver, kidneys, intestine and the oesophagus. In three animals, a pathogenic bacterium caused inflammatory lesions in several organs. We did not find signs for epizootic diseases or pathologies, which would explain the declining species numbers.

Abstract

The Common Eider (Somateria mollissima) inhabits the entire northern hemisphere. In northern Europe, the flyway population reaches from the southern Wadden Sea to the northern Baltic coast. The European population is classified as endangered due to declines in Common Eider numbers across Europe since 1990. In this study, we assessed 121 carcasses of Common Eiders, captured incidentally in gillnets in the Western Baltic between 2017 and 2019. The most common findings were parasitic infections of the intestine by acanthocephalans in 95 animals, which correlated with enteritis in 50% of the cases. Parasites were identified as Profilicollis botulus in 25 selected animals. Additionally, oesophageal pustules, erosions, and ulcerations, presumably of traumatic origin, were frequently observed. Nephritis and hepatitis were frequent, but could not be attributed to specific causes. Lung oedema, fractures and subcutaneous haemorrhages likely resulted from entangling and drowning. Two Common Eiders had mycobacterial infections and in one of these, Mycobacterium avium subspecies (ssp.) avium was identified. This study gives an overview of morphological changes and infectious diseases from one location of the European flyway population. It contributes to future health studies on Common Eiders in the Baltic and Wadden Seas by providing baseline information to compare with other areas or circumstances.

Expanding the Universe of Hemoplasmas: Multi-Locus Sequencing Reveals Putative Novel Hemoplasmas in Lowland Tapirs (Tapirus terrestris), the Largest Land Mammals in Brazil

The lowland tapir (Tapirus terrestris) is the largest land mammal in Brazil and classified as a vulnerable species, according to the assessment of the risk of extinction. The present study aimed at investigating the occurrence and genetic diversity of hemoplasmas in free-ranging T. terrestris from the Brazilian Pantanal and Cerrado biomes. Blood samples were collected from 94 living and eight road-killed tapirs, totalizing 125 samples Conventional PCR targeting four different genes (16S rRNA, 23S rRNA, RNAse P, and dnaK) were performed, and the obtained sequences were submitted for phylogenetic, genotype diversity, and distance analyses. The association between hemoplasma positivity and possible risk variables (age, gender, and origin) was assessed. Out of 122 analyzed samples, 41 (41/122; 33.61% CI: 25.84-42.38%) were positive in the 16S rRNA-based PCR assay for hemoplasmas. Positivity for hemoplasmas did not differ between tapirs' gender and age. Tapirs from Pantanal were 5.64 times more likely to present positive results for hemoplasmas when compared to tapirs sampled in Cerrado. BLASTn, phylogenetic, genotype diversity, and distance analyses performed herein showed that the sampled lowland tapirs might be infected by two genetically distinct hemoplasmas, namely 'Candidatus Mycoplasma haematoterrestris' and 'Candidatus Mycoplasma haematotapirus'. While the former was positioned into "Mycoplasma haemofelis group" and closely related to 'Candidatus Mycoplasma haematoparvum, the latter was positioned into "Mycoplasma suis group" and closely related to 'Candidatus Mycoplasma haematobos'. The impact of both putative novel species on tapir health status should be investigated.

TREATMENT OF MYCOBACTERIOSIS CAUSED BY MYCOBACTERIUM AVIUM SSP. HOMINISSUIS IN A GROUP OF CAPTIVE LOWLAND TAPIRS (TAPIRUS TERRESTRIS)

Tapirs are a taxonomic group with a high susceptibility to mycobacterial diseases. However, successful therapy has only been documented sporadically. Here treatment of mycobacteriosis diagnosed in three, one male and two female, lowland tapirs (Tapirus terrestris) in a zoo in Germany is reported. Two of the animals showed chronic mild respiratory signs, and conventional therapy did not improve the condition. Culture of broncho-alveolar lavage (BAL) samples was positive for Mycobacterium avium ssp. hominissuis. Upon airway endoscopy, bronchial edema and increased mucus production were visible. Initially, all three infected tapirs received oral antimycobacterial therapy consisting of 5 mg/kg body weight isoniazid, 10 mg/kg rifampicin, and 10 mg/kg clarithromycin q24h. Based on therapeutic drug level monitoring, the doses of rifampicin were adjusted to 12 and 15 mg/kg in the females and the male, respectively. The treatment with all three drugs was continued for 11 mon. Six months into treatment, the clinical condition resolved, and repeated BAL samples of all three tapirs tested negative for mycobacteria by culture. Here the approach for a treatment protocol with minimal side effects suitable to control infections with nontuberculous mycobacteria in lowland tapirs is reported.