Surveying bovine digital dermatitis and non-healing bovine foot lesions for the presence of Fusobacterium necrophorum, Porphyromonas endodontalis and Treponema pallidum.

BACKGROUND: Non-healing bovine foot lesions, including non-healing white line disease, non-healing sole ulcer and toe necrosis, are an increasingly important cause of chronic lameness that are poorly responsive to treatment. Recent studies have demonstrated a high-level association between these non-healing lesions and the Treponema phylogroups implicated in bovine digital dermatitis (BDD). However, a polymicrobial aetiology involving other gram-stain-negative anaerobes is suspected. METHODS: A PCR-based bacteriological survey of uncomplicated BDD lesions (n=10) and non-healing bovine foot lesions (n=10) targeting Fusobacterium necrophorum, Porphyromonas endodontalis, Dichelobacter nodosus and Treponema pallidum/T. paraluiscuniculi was performed. RESULTS: P. endodontalis DNA was detected in 80.0% of the non-healing lesion biopsies (p=<0.001) but was entirely absent from uncomplicated BDD lesion biopsies. When compared to the BDD lesions, F. necrophorum was detected at a higher frequency in the non-healing lesions (33.3% vs 70.0%, respectively), whereas D. nodosus was detected at a lower frequency (55.5% vs 20.0%, respectively). Conversely, T. pallidum/T. paraluiscuniculi DNA was not detected in either lesion type. CONCLUSION: The data from this pilot study suggest that P. endodontalis and F. necrophorum should be further investigated as potential aetiological agents of non-healing bovine foot lesions. A failure to detect syphilis treponemes in either lesion type is reassuring given the potential public health implications such an infection would present.

Facial and genital lesions in baboons (Papio anubis) of Kibale National Park, Uganda.

We describe and document with digital images two adult male baboons (Papio anubis) from the Kibale National Park, Uganda who were infected with some kind of disease having clinical signs suggestive of Treponema pallidum. One of these males was missing his premaxilla, part of the maxilla, upper incisors, canines, and possibly the first premolars. The condition of his scrotum was not seen. The other adult male had prominent inflammation of his scrotum and, to a lesser extent, his penis. Otherwise, both males appeared normal and healthy and were apparently well integrated into the same social group. These observations suggest that an earlier report of an adult female baboon living in the same area who was missing her entire premaxilla and nose and most of her maxilla may have been suffering from a similar infection, rather than a congenital disorder, as previously speculated. If these lesions were due to T. pallidum infections, then this disease has a greater geographical distribution among non-human primates than previously known.

Development of tissue inflammation accompanied by NLRP3 inflammasome activation in rabbits infected with Treponema pallidum strain Nichols.

BACKGROUND: The inflammasome responses in Treponema pallidum infection have been poorly understood to date. This study aimed to investigate the expression of the nucleotide-binding leucine-rich receptor protein 3 (NLRP3) inflammasome in the development of tissue inflammation in rabbits infected with T. pallidum. METHODS: Forty-five rabbits were randomly assigned to a blank group or an infection group, and the latter was divided into no benzathine penicillin G (BPG) and BPG treatment subgroups. Rabbits in the infection group were injected intradermally with 0.1 mL of a 107/mL T. pallidum suspension at 10 marked sites along the back, and the blank group was treated with normal saline. The BPG treatment subgroup received 200,000 U of BPG administered intramuscularly twice, at 14 d and 21 d post-infection. The development of lesions was observed, and biopsies of the injection site and various organs, including the kidney, liver, spleen, lung, and testis, were obtained for NLRP3, caspase-1, and interleukin-1ß (IL-1ß) mRNA analysis during infection. Blood was also collected for the determination of IL-1ß concentration. RESULTS: Rabbits infected with T. pallidum (both the BPG treatment and no BPG treatment subgroups), exhibited NLRP3 inflammasome activation and IL-1ß secretion in cutaneous lesions, showing a trend in elevation to decline; NLRP3 mRNA expression reached a peak at 18 d in the BPG treatment subgroup and 21 d in the no BPG treatment subgroup and returned to "normal" levels [vs. the blank group (P > 0.05)] at 42 d post-infection. The trend was similar to the change in cutaneous lesions in the infected rabbits, which reached a peak at 16 d in the BPG treatment subgroup and 18 d in the no BPG treatment subgroup. NLRP3, caspase-1, and IL-1ß mRNA expression levels were slightly different in different organs. NLRP3 inflammasome activation was also observed in the kidney, liver, lung, spleen and testis. IL-1ß expression was observed in the kidney, liver, lung and spleen; however, there was no detectable level of IL-1ß in the testes of the infected rabbits. CONCLUSIONS: This study established a clear link between NLRP3 inflammasome activation and the development of tissue inflammation in rabbits infected with T. pallidum. BPG therapy imperceptibly adjusted syphilitic inflammation.

Is there a difference between hare syphilis and rabbit syphilis? Cross infection experiments between rabbits and hares.

Cross infection of rabbits and hares with Treponema paraluiscuniculi from rabbits and the related microorganism from hares, which was provisionally named "Treponema paraluisleporis", revealed that T. paraluiscuniculi affects rabbits clinically, but only causes seroconversion in hares without causing clinical disease, while "T. paraluisleporis" induces disease in both rabbits and hares. The 16S rRNA gene of "T. paraluisleporis" was sequenced (GenBank acc. no. JX899416) and compared to the sequence of T. paraluiscuniculi strain Cuniculi A. A phylogenetic tree based on the sequence alignment of 2002 bp taken from several treponemal strains was constructed. Both "T. paraluisleporis" and T. paraluiscuniculi are clustered together indicating their common origin. The close phylogenetic relatedness of both representatives supports the conclusion that subspecies or ecovar status should be given to these strains rather than species status. A more appropriate species name might be Treponema paraluisleporidarum. The genitive refers to the nominative Leporidae (family of rabbits and hares). The naturally occurring strain in rabbits would than be T. paraluisleporidarum ecovar Cuniculus and the strain from hares T. paraluisleporidarum ecovar Lepus. Since the former seems to have fewer physiological hosts, ecovar Lepus may represent an evolutionary ancestor of ecovar Cuniculus.

Treponemal infection in free-ranging European brown hares (Lepus europaeus) in central Italy: serology and epidemiology.

In the winters of 2008 and 2009, treponemal infections in 154 free-ranging wild European brown hares (Lepus europaeus) from Central Italy were diagnosed by serologic tests for human syphilis. Antibodies were found in 51/154 samples (33%). Antibody prevalence was positively correlated with age and with population density. There were no significant differences in prevalence between sexes.

Treponema pallidum infection in the wild baboons of East Africa: distribution and genetic characterization of the strains responsible.

It has been known for decades that wild baboons are naturally infected with Treponema pallidum, the bacterium that causes the diseases syphilis (subsp. pallidum), yaws (subsp. pertenue), and bejel (subsp. endemicum) in humans. Recently, a form of T. pallidum infection associated with severe genital lesions has been described in wild baboons at Lake Manyara National Park in Tanzania. In this study, we investigated ten additional sites in Tanzania and Kenya using a combination of macroscopic observation and serology, in order to determine whether the infection was present in each area. In addition, we obtained genetic sequence data from six polymorphic regions using T. pallidum strains collected from baboons at two different Tanzanian sites. We report that lesions consistent with T. pallidum infection were present at four of the five Tanzanian sites examined, and serology was used to confirm treponemal infection at three of these. By contrast, no signs of treponemal infection were observed at the six Kenyan sites, and serology indicated T. pallidum was present at only one of them. A survey of sexually mature baboons at Lake Manyara National Park in 2006 carried out as part of this study indicated that roughly ten percent displayed T. pallidum-associated lesions severe enough to cause major structural damage to the genitalia. Finally, we found that T. pallidum strains from Lake Manyara National Park and Serengeti National Park were genetically distinct, and a phylogeny suggested that baboon strains may have diverged prior to the clade containing human strains. We conclude that T. pallidum infection associated with genital lesions appears to be common in the wild baboons of the regions studied in Tanzania. Further study is needed to elucidate the infection's transmission mode, its associated morbidity and mortality, and the relationship between baboon and human strains.

Experimental transmission of rabbit syphilis.

Rabbit syphilis was experimentally transmitted from clinical cases to healthy rabbits. The purpose was to evaluate changes in RPR titers during the course of infection and to detect the pathogenic organism. Two of three littermate rabbits were inoculated topically. One rabbit became symptomatic, with typical clinical signs on its genitalia about 8 weeks after inoculation and a marked rise in RPR titers, another remained asymptomatic with a moderate rise in titers, and the control rabbit remained negative. These results supported the specific relationship between clinical signs and RPR titers. Histopathological examination of the skin lesion from the symptomatic rabbit revealed spirochetes.

Chloramphenicol treatment for rabbit syphilis.

Penicillin, the recommended treatment for rabbit syphilis, sometimes induces adverse effects. The efficacy of oral chloramphenicol was evaluated in 39 cases of rabbit syphilis to establish a safe and efficient treatment for this disease in companion rabbits. All cases clinically improved and recovered promptly. Fourteen of 39 cases (35.9%) relapsed, but most remained chloramphenicol sensitive. Since safety take priority over efficacy in treating syphilis in companion rabbits, chloramphenicol should be chosen as a first-line agent, as a general rule. Three-week administration of chloramphenicol may be adequate at the initial onset of disease. When relapse occurs repeatedly or the rabbit owner cannot administer the medicine adequately, treatment with penicillin should be considered.

Rabbit syphilis diagnosed clinically in household rabbits.

This paper deals with 16 cases presented from April to December 2001 and diagnosed clinically as rabbit syphilis, because they showed distinct lesions around the nose and/or mouth, responded to chemotherapy, and the "Rapid Plasma Reagin" test was positive. Twelve cases exhibited initial symptoms and four were relapses. Lesions around the genitalia and/or anus as well as the nose and/or mouth were seen in 8 cases, and 6 cases indicated sneezing. Fifteen cases were successfully treated with oral administration of chloramphenicol, and one was treated with long-acting penicillin by intramuscular injection. The mean age of onset was 8.8 months. As none of these cases had any mating history, the disease was likely to be maternally transmitted.

Experimental syphilis and serological examination for treponematosis in hares.

Of 202 captive hares studied, many of which had lesions on their external genital organs or testicular atrophy or both, 27% had positive serological tests for syphilis although dark-field examination of extracts of atrophic testes was negative. A total of 12 hares that were nonreactive for the serological test for syphilis was inoculated with Treponema pallidum, 9 intratesticularly and 3 intradermally. Six of the animals inoculated intratesticularly exhibited orchitis after 7 days with an associated accumulation of treponemes. No chancres developed in the intracutaneously inoculated animals during a 27-day period of observation. These results provide additional evidence to support the contention that endemic treponematosis occurs in wild hares and suggest that hares are moderately resistant to experimental infection with T. pallidum.

The effect of Treponema pallidum on mouse survival.

Intraperitoneal infection with Treponema pallidum did not shorten the lives of inbred CBA mice. One hundred and fifty infected mice survived to a mean age of 41-24 months and 60 uninfected mice to a mean age of 41-38 months.