Experimental infections of mice and pigs with Streptococcus suis type 2.

Five inbred strains of mice were tested for their susceptibility to Streptococcus suis type 2 including the type strain, two isolates from meningitis in pigs and two isolates from tonsils of clinically healthy pigs. C57BL/6, ICR and ddY strain mice showed lower susceptibility to all strains of S. suis type 2 than BALB/c and SS strain mice. The type strain and the isolates from diseased pigs produced septicaemia and meningitis in BALB/c and SS mice inoculated with 10(8) colony forming unit of the bacteria and 60 to 100% of these infected mice died. On the other hand, mice inoculated with the isolates from healthy pigs showed mild clinical signs but none of them died. In BALB/c mice which died or developed nervous signs, the purulent meningo-encephalitis, myocarditis, ophthalmitis, labyrinthitis and otitis media were observed. S. suis type 2 antigen was demonstrated in these lesions by immunoperoxidase staining using rabbit S. suis type 2 antiserum. These results were similar to those in the experimentally infected pigs with these virulent and avirulent strains against mice. These results indicate that BALB/c and SS strains of mice are useful as an experimental model of S. suis type 2 infections in pigs, and that there are virulent and avirulent strains against mice and pigs among the strains of S. suis type 2.     

Evaluation of serum free thyroxine and thyrotropin concentrations in the diagnosis of canine hypothyroidism

Canine thyroid-stimulating hormone (cTSH), total thyroxine (T4) and free T4 by equilibrium dialysis (fT4d) were measured in serum samples from 107 dogs with clinical signs suggestive of hypothyroidism in which the diagnosis was either confirmed (n = 30) or excluded (n = 77) by exogenous TSH response testing. Median serum total T4 and fT4d concentrations were significantly lower and cTSH significantly higher (P < 0.001) in hypothyroid compared with euthyroid dogs. Differential positive rate analysis determined optimal cut-off values of less than 14.9 nmol/litre (total T4), less than 5.42 pmol/litre (fT4d), greater than 0.68 ng/ml (cTSH), less than 17.3 (T4 to cTSH ratio), and less than 7.5 (fT4d to cTSH ratio) for hypothyroidism. These had a sensitivity and specificity of 100 and 75.3 per cent, 80 and 93.5 per cent, 86.7 and 81.8 per cent, 86.7 and 92.2 per cent, and 80 and 97.4 per cent, respectively, for diagnosing hypothyroidism. Corresponding areas under the receiver operating characteristic curves were 0.92, 0.93, 0.87, 0.93 and 0.93. Unexpectedly low cTSH values in hypothyroid dogs may have resulted from concurrent non-thyroidal illness. Unexpectedly high serum cTSH values in the euthyroid dogs might have resulted from recovery from illness or concurrent potentiated sulphonamide therapy. Measurement of endogenous cTSH concentration is a valuable diagnostic tool for canine hypothyroidism if used in association with assessment of T4. Estimation of fT4d added only limited additional information over total T4 measurement.     

Fatal Gastrointestinal Infection with ‘Flexispira rappini’‐Like Organisms in a Cat

A 4‐month‐old male British Blue cat with catarrhal to haemorrhagic enteritis showed massive colonization of the stomach, small intestine and caecum with spiral‐shaped bacilli. In the stomach, organisms were located in foveolae and gland lumina and within unaltered and degenerate epithelial cells. Inflammatory infiltration was moderate and T cell dominated. In the intestine, bacilli were found in the gut lumen, between villi, in crypt lumina and within epithelial cells. Degeneration of crypt epithelial cells as well as crypt dilation and moderate to massive macrophage‐dominated infiltration of the mucosa and submucosa were observed. Immunohistochemically, bacilli were positive with an antibody against Helicobacter. Ultrastructurally, the organisms strongly resembled ‘Flexispira rappini’, a spiral‐shaped Helicobacter species known as a normal intestinal colonizer in dogs and mice.     

Review of left-to-right shunting patent ductus arteriosus and short term outcome in 98 dogs

The case records of 98 dogs with a left-to-right shunting patent ductus arteriosus (PDA) were reviewed. There were 35 breeds represented, with a female to male ratio of 3:1. Forty per cent of the dogs were older than one year at initial presentation and 31 per cent had clinical signs attributable to PDA. A left heart base continuous murmur of grade IV/VI or higher was noted in 90 per cent of the dogs. On electrocardiography, the most common abnormalities were tall R waves (63 per cent) and deep QII waves (62 per cent). The radiographic triad of dilation of the descending aorta with enlargement of the main pulmonary artery segment and left atrium, typical of PDA, was noted in only 26 per cent of cases. Two-dimensional (2D) and M-mode echocardiography detected left atrial enlargement (35 per cent) and an increased left ventricular diameter in diastole (82 per cent) and systole (84 per cent) as the most common abnormalities. Doppler echocardiography demonstrated increased aortic outflow velocities in 66 per cent of cases. The overall short-term successful outcome in this study was 95 per cent. There was no significant difference between surgical ductal ligation using a standard technique or the Jackson-Henderson technique in terms of survival, occurrence of haemorrhage or residual shunting. The number of interventional procedures used in this study was too low for statistical comparison, but there appeared to be a trend towards a higher rate of residual shunting and a lower fatality rate using a coil occlusion technique.     

The Epidemiology and Characteristics of Q fever and Co‐infections with Scrub Typhus,Murine Typhus or Leptospirosis in Taiwan: A Nationwide Database Study

Q fever (QF) is a worldwide zoonosis associated with outbreaks. Only a few nationwide studies regarding the surveillance and epidemiology of human QF have been reported. Although QF is endemic in Taiwan, a nationwide database investigation of the epidemiology and characteristics of QF and its associations with scrub typhus (ST), murine typhus (MT) and leptospirosis (LS) has never been reported. We analysed nationwide databases of suspected QF, ST, MT and LS cases from October 2007 to December 2014 obtained from the Centers for Disease Control, Taiwan. A total of 468 (4.2%) QF cases were identified among 11 109 suspected QF cases. QF cases were mainly distributed in the southern and Kaohsiung–Pingtung regions but rarely in the eastern region. Compared to non‐QF cases, QF cases had significantly higher percentages of males (88.7 versus 66.2%) and high‐risk occupations (farming, animal husbandry or veterinary medicine) (16.2 versus 10.5%). But the percentages of specific animal contact, including cattle (0.6 versus 0.8%) and goats (0.9 versus 1.0%), were low in both. The majority of suspected QF cases (89.4%) were simultaneously suspected with ST, MT or LS, and the combinations of suspected diseases differed between regions. The number of suspected QF cases from the eastern region decreased since 2009, which was not observed in other regions. A total of 1420 (12.8%) cases had confirmed diseases, including QF (453, 4.1%), QF+ST (7, 0.06%), QF+MT (4, 0.04%), QF+LS (4, 0.04%), MT (186, 1.7%), ST (545, 4.9%), ST+LS (11, 0.1%) and LS (210, 1.9%). Compared to cases of unknown disease, QF cases had larger percentages of high‐risk occupations (16.2 versus 9.6%) but similar histories of animal contact (29.8 versus 25.1%). QF is an endemic disease in southern Taiwan. It is difficult to differentiate QF from ST, MT or LS only by high‐risk occupations and history of animal contact, and co‐infection of QF with these diseases should be considered.