The natural transmission routes of the three feline haemotropic mycoplasmas – Mycoplasma haemofelis, ‘Candidatus Mycoplasma haemominutum’, and ‘Candidatus Mycoplasma turicensis’ (CMt) – are largely unknown. Since CMt has been detected in the saliva of infected cats using PCR, we hypothesised that direct transmission via social or aggressive contact may occur. The aim of this study was to evaluate this transmission route. CMt-positive saliva and blood samples were obtained from three prednisolone-treated specific pathogen-free (SPF) cats that were infected intraperitoneally with CMt. Five SPF cats were inoculated with CMt-positive saliva or blood subcutaneously to mimic cat bites, and five cats were inoculated orally with blood or oronasally with saliva to mimic social contact. Blood samples were monitored for CMt infection using quantitative real-time PCR and for seroconversion using a novel western blot assay. Neither oronasal nor subcutaneous inoculation with CMt-positive saliva led to CMt infection in the recipient cats, as determined by PCR, independent of prior prednisolone treatment. However, when blood containing the same CMt dose was given subcutaneously, 4 of the 5 cats became PCR-positive, while none of the 5 cats inoculated orally with up to 500 μL of CMt-positive blood became PCR-positive. Subsequently, the latter cats were successfully subcutaneously infected with blood. All 13 CMt-exposed cats seroconverted. In conclusion, CMt transmission by social contact seems less likely than transmission by aggressive interaction. The latter transmission may occur if the recipient cat is exposed to blood from an infected cat.

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Mycoplasma suis belongs to the hemotrophic mycoplasma group and causes infectious anemia in pigs. According to the present state of knowledge, this organism adheres to the surface of erythrocytes but does not invade them. We found a novel M. suis isolate that caused severe anemia in pigs with a fatal disease course. Interestingly, only marginal numbers of the bacteria were visible on and between the erythrocytes in acridine orange-stained blood smears for acutely diseased pigs, whereas very high loads of M. suis were detected in the same blood samples by quantitative PCR. These findings indicated that M. suis is capable of invading erythrocytes. By use of fluorescent labeling of M. suis and examination by confocal laser scanning microscopy, as well as scanning and transmission electron microscopy, we proved that the localization of M. suis was intracellular. This organism invades erythrocytes in an endocytosis-like process and is initially surrounded by two membranes, and it was also found floating freely in the cytoplasm. In conclusion, we were able to prove for the first time that a member of the hemotrophic mycoplasma group is able to invade the erythrocytes of its host. Such colonization should protect the bacterial cells from the host's immune response and hamper antibiotic treatment. In addition, an intracellular life cycle may explain the chronic nature of hemotrophic mycoplasma infections and should serve as the foundation for novel strategies in hemotrophic mycoplasma research (e.g., treatment or prophylaxis).Mycoplasma suis is a member of the family Mycoplasmataceae. This organism belongs to a group of uncultivable highly specialized bacteria which parasitize the surface of erythrocytes of a variety of mammals (34). These species represent a distinct new cluster in the genus Mycoplasma and have been given the trivial name hemotrophic mycoplasmas (HM). Infections with HM are identified clinically by overt life-threatening hemolytic anemia or by subtle chronic anemia characterized by infertility, immune suppression, and greater susceptibility to infections (34). It is noteworthy that organisms that morphologically resemble HM have also been detected in the blood of humans (1,8,42,50).M. suis causes febrile acute icteroanemia in pigs (IAP), which is accompanied by high numbers of M. suis cells in the blood, as confirmed by microscopy as well as by PCR (18,21,34). Clinical symptoms are successfully cured by treatment with tetracycline. Nevertheless, once pigs are infected with M. suis, they remain lifelong carrier animals and therefore are epidemiologically important (19). Chronic M. suis infections result in reproductive disorders in sows, growth retardation in piglets, and increased susceptibility to respiratory and enteric infections in feeder pigs. M. suis occurs worldwide, and chronic IAP, in particular, is of major economic importance (19).Contrary to the well-established clinical picture of IAP (i.e., high morbidity and low mortality), we recently observed an increased incidence of acute IAP in feed...

Bovine tuberculosis (bTB) caused by Mycobacterium bovis or M. caprae has recently (re-) emerged in livestock and wildlife in all countries bordering Switzerland (CH) and the Principality of Liechtenstein (FL). Comprehensive data for Swiss and Liechtenstein wildlife are not available so far, although two native species, wild boar (Sus scrofa) and red deer (Cervus elaphus elaphus), act as bTB reservoirs elsewhere in continental Europe. Our aims were (1) to assess the occurrence of bTB in these wild ungulates in CH/FL and to reinforce scanning surveillance in all wild mammals; (2) to evaluate the risk of a future bTB reservoir formation in wild boar and red deer in CH/FL. Tissue samples collected from 2009 to 2011 from 434 hunted red deer and wild boar and from eight diseased ungulates with tuberculosis-like lesions were tested by direct real-time PCR and culture to detect mycobacteria of the Mycobacterium tuberculosis complex (MTBC). Identification of suspicious colonies was attempted by real-time PCR, genotyping and spoligotyping. Information on risk factors for bTB maintenance within wildlife populations was retrieved from the literature and the situation regarding identified factors was assessed for our study areas. Mycobacteria of the MTBC were detected in six out of 165 wild boar (3.6%; 95% CI: 1.4–7.8) but none of the 269 red deer (0%; 0–1.4). M. microti was identified in two MTBC-positive wild boar, while species identification remained unsuccessful in four cases. Main risk factors for bTB maintenance worldwide, including different causes of aggregation often resulting from intensive wildlife management, are largely absent in CH and FL. In conclusion, M. bovis and M. caprae were not detected but we report for the first time MTBC mycobacteria in Swiss wild boar. Present conditions seem unfavorable for a reservoir emergence, nevertheless increasing population numbers of wild ungulates and offal consumption may represent a risk.

Lung and intestine of 49 pigs with respiratory diseases and endocervical swabs from 205 sows with reproductive disorders were investigated for chlamydial infection by polymerase chain reaction. PCR primers targeted DNA sequences on the chlamydial omp1 or omp2 genes. PCR amplicons were generated from 49.0% of pigs with respiratory disease, from 60.0% of sows with reproductive disorders, from 24.5% of respiratory healthy controls, but from no endocervical swabs from fertile sows. By DNA hybridization, a high prevalence of mixed infections with Chlamydophila abortus and Chlamydia suis in the porcine lung and intestine was found and confirmed by RFLP and nucleotide analysis. Of the omp1-PCR amplicons from endocervical swabs 81.3% were identified as Chlamydophila abortus, indicating an association of this chlamydial species with reproductive disorders in sows. Nucleotide sequence analysis of omp1-amplicons identified as deriving from Chlamydia suis shared a maximum of 82.7% homology with the reference strain S45.