Ehrlichiosis is a disease caused by rickettsial organisms belonging to the genus Ehrlichia. In Brazil, molecular and serological studies have evaluated the occurrence of Ehrlichia species in dogs, cats, wild animals and humans. Ehrlichia canis is the main species found in dogs in Brazil, although E. ewingii infection has been recently suspected in five dogs. Ehrlichia chaffeensis DNA has been detected and characterized in mash deer, whereas E. muris and E. ruminantium have not yet been identified in Brazil. Canine monocytic ehrlichiosis caused by E. canis appears to be highly endemic in several regions of Brazil, however prevalence data are not available for several regions. Ehrlichia canis DNA also has been detected and molecularly characterized in three domestic cats, and antibodies against E. canis were detected in free-ranging Neotropical felids. There is serological evidence suggesting the occurrence of human ehrlichiosis in Brazil but its etiologic agent has not yet been established. Improved molecular diagnostic resources for laboratory testing will allow better identification and characterization of ehrlichial organisms associated with human ehrlichiosis in Brazil.

Mycobacterium bovis is the main causative agent of zoonotic tuberculosis in humans and frequently devastates livestock and wildlife worldwide. Previous studies suggested the existence of genetic groups of M. bovis strains based on limited DNA markers (a.k.a. clonal complexes), and the evolution and ecology of this pathogen has been only marginally explored at the global level. We have screened over 2,600 publicly available M. bovis genomes and newly sequenced four wildlife M. bovis strains, gathering 1,969 genomes from 23 countries and at least 24 host species, including humans, to complete a phylogenomic analyses. We propose the existence of four distinct global lineages of M. bovis (Lb1, Lb2, Lb3, and Lb4) underlying the current disease distribution. These lineages are not fully represented by clonal complexes and are dispersed based on geographic location rather than host species. Our data divergence analysis agreed with previous studies reporting independent archeological data of ancient M. bovis (South Siberian infected skeletons at ∼2,000 years before present) and indicates that extant M. bovis originated between 715 and 3,556 years BP, with later emergence in the New World and Oceania, likely influenced by trades among countries.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the coronavirus disease 2019 (COVID-19), is the causative infectious agent of the current pandemic. As researchers and health professionals are still learning the capabilities of this virus, public health concerns arise regarding the zoonotic potential of SARS-CoV-2. With millions of people detected with SARS-CoV-2 worldwide, reports of companion animals possibly infected with the virus started to emerge. Therefore, our aim is to review reported cases of animals naturally infected with SARS-CoV-2, particularly companion pets, shedding light on the role of these animals in the epidemiology of COVID-19.

Mycobacterium bovis causes bovine tuberculosis and is the main organism responsible for zoonotic tuberculosis in humans. We performed the sequencing, assembly and annotation of a Brazilian strain of M. bovis named SP38, and performed comparative genomics of M. bovis genomes deposited in GenBank. M. bovis SP38 has a traditional tuberculous mycobacterium genome of 4,347,648 bp, with 65.5% GC, and 4,216 genes. The majority of CDSs (2,805, 69.3%) have predictive function, while 1,206 (30.07%) are hypothetical. For comparative analysis, 31 M. bovis, 32 M. bovis BCG, and 23 Mycobacterium tuberculosis genomes available in GenBank were selected. M. bovis RDs (regions of difference) and Clonal Complexes (CC) were identified in silico. Genome dynamics of bacterial groups were analyzed by gene orthology and polymorphic sites identification. M. bovis polymorphic sites were used to construct a phylogenetic tree. Our RD analyses resulted in the exclusion of three genomes, mistakenly annotated as virulent M. bovis. M. bovis SP38 along with strain 35 represent the first report of CC European 2 in Brazil, whereas two other M. bovis strains failed to be classified within current CC. Results of M. bovis orthologous genes analysis suggest a process of genome remodeling through genomic decay and gene duplication. Quantification, pairwise comparisons and distribution analyses of polymorphic sites demonstrate greater genetic variability of M. tuberculosis when compared to M. bovis and M. bovis BCG (p ≤ 0.05), indicating that currently defined M. tuberculosis lineages are more genetically diverse than M. bovis CC and animal-adapted MTC (M. tuberculosis Complex) species. As expected, polymorphic sites annotation shows that M. bovis BCG are subjected to different evolutionary pressures when compared to virulent mycobacteria. Lastly, M. bovis phylogeny indicates that polymorphic sites may be used as markers of M. bovis lineages in association with CC. Our findings highlight the need to better understand host-pathogen co-evolution in genetically homogeneous and/or diverse host populations, considering the fact that M. bovis has a broader host range when compared to M. tuberculosis. Also, the identification of M. bovis genomes not classified within CC indicates that the diversity of M. bovis lineages may be larger than previously thought or that current classification should be reviewed.

Recent studies have been conducted in Brazil using molecular techniques for the detection of hemotrophic mycoplasmas in several mammals. In domestic cats, Mycoplasma haemofelis, 'Candidatus M. haemominutum', and 'Candidatus M. turicensis' infections have been identified. These species have also been found in free-ranging and captive neotropical felid species. Two canine hemoplasmas, Mycoplasma haemocanis and 'Candidatus Mycoplasma haematoparvum', have been identified in dogs. In commercial swine populations, Mycoplasma suis was found to be highly prevalent, especially in sows. Moreover, novel mycoplasma species have been identified in Brazilian commercial pigs and domestic dogs. A hemoplasma infection in a human patient infected with the human immunodeficiency virus (HIV) was also recently documented. In conclusion, hemoplasma species are common and important infectious agents in Brazil. Further studies should be conducted to better understand their impact on pets, production animals, and wildlife fauna, as well as their role as zoonotic agents, particularly in immunocompromised patients.Keywords: Hemoplasma, Mycoplasma haemofelis, Mycoplasma suis, HIV. ResumoEstudos recentes utilizando técnicas moleculares para a detecção de micoplasmas hemotróficos em diferentes mamíferos têm sido conduzidos no Brasil. Em gatos domésticos, infecções por Mycoplasma haemofelis, 'Candidatus M. haemominutum' e 'Candidatus M. turicensis' foram identificadas. Estas espécies também foram encontradas em felídeos neotropicais de vida livre e de cativeiro. Dois hemoplasmas caninos, Mycoplasma haemocanis e 'Candidatus Mycoplasma haematoparvum', foram identificados em cães domésticos. Em populações comerciais de suínos, Mycoplasma suis possui alta prevalência, especialmente em porcas. Além disso, novas espécies de hemoplasmas foram detectadas em suínos comercias e cães. Infecção por um hemoplasma em um paciente humano infectado com o vírus da imunodeficiência humana (HIV) foi recentemente documentada. Em conclusão, espécies de hemoplasmas são comuns e importantes agentes de infecções no Brasil. Estudos futuros devem ser conduzidos para melhor entender seu impacto em cães e gatos, animais de produção e na fauna silvestre, e também para determinar o seu papel como agentes zoonóticos, particularmente em pacientes imunocomprometidos.Palavras-chave: Hemoplasma, Mycoplasma haemofelis, Mycoplasma suis, HIV.