Sero-epidemiology of canine leptospirosis in Trinidad: serovars, implications for vaccination and public health.

A sero-epidemiological study on canine leptospirosis was conducted in house, stray, farm and hunting dogs, as well as in suspect cases of clinical canine leptospirosis. Serum samples were collected from apparently healthy (vaccinated and non-vaccinated), house dogs. A questionnaire was administered to the owners to elicit information on risk factors for leptospirosis. The microscopic agglutination test was used to screen for leptospirosis using 17 international serovars. Reciprocal titres of between 100 and <800 were considered as evidence of past exposure while reciprocal titres of 800 or greater were classified as suggestive of acute/current infection. Of a total of 419 serum samples tested, 61 (14.6%) were seropositive for Leptospira agglutinins, 23 (5.5%) had mixed infections and 16 (3.8%) had current infection. Amongst 50 suspected cases of clinical leptospirosis, 24 (48.0%) were seropositive and only 13 (26.0%) had current infection compared with 10 (6.3%) and three (1.9%) of 160 apparently healthy house dogs respectively. The difference was statistically significant (P < 0.05; chi2). Twelve (25.5%) of 47 hunting dogs, 10 (20.4%) of 49 farm dogs and five (4.4%) of 113 stray dogs were seropositive (P < 0.05; chi2). Overall, a total of nine serovars were detected with serovars mankarso, icterohaemorrhagiae RGA, autumnalis and copenhageni being involved in 29 (47.5%), 20 (32.8%), 25 (41.0%) and 10 (16.4%) respectively in 61 seropositive dogs (P < 0.05; chi2). Serovar mankarso was most predominant in seropositive apparently healthy dogs, 37.8% (14/37), suspected clinical cases of leptospirosis, 62.5% (15/24) compared with serovar icterohaemorrhagiae with a frequency of 21.6% (8/37) and 50.0% (12/24), the difference being statistically significant (P < 0.05; chi2). Although all vaccines used for prevention of canine leptospirosis in the country contain serovars canicola and icterohaemorrhagiae, serovar mankarso was mostly associated with infection and disease and may be a good candidate for inclusion in the vaccine used locally. The public health risk posed to owners of dogs infected with Leptospira cannot be over-emphasized considering the zoonotic nature of the disease.

The nutrition of the budgerigar (Melopsittacus undulatus).

Growing interest in the nutrition of the budgerigar (Melopsittacus undulatus) has highlighted the paucity of knowledge in this area. The aims of this study were to review the available literature on their individual nutrient requirements and relate this to the nutrient content of their predominantly seed-based diet and to investigate the effect of the bird's daily energy requirement on the fluctuations in body weight. Studies were conducted at the Waltham Centre to measure the relationship between daily metabolizable energy intake (kJ/kg BW) and body weight change (g/d) for groups of adult budgerigars. The birds were found to require daily 48-128 kJ/bird depending on their body mass (birds in our colony typically weigh 30-80 g). During a series of breeding trials the daily energy intake for a breeding pair plus their three chicks, at peak energy intake, was found to be 483-505 kJ (at pairing, the mean daily energy intake of the breeding pairs was 231 kJ). Apparent metabolizability of the major nutrients from a seed diet were generally found to be greater than 80%, which allows these birds to assimilate the high levels of energy needed for their basal metabolism. In summary, the nutrient requirements of the budgerigar (where known) were found to be similar to those of other avian species, however, further work is needed, especially in the area of availability of key nutrients. Further developments in the dietary management of these birds will only be possible if researchers can overcome the birds' poor acceptance of novel foods and satisfy their high basal energy requirements before establishing their requirements for individual nutrients.

Aortic root abscess presenting as unstable angina due to extrinsic compression of the left coronary artery.

Coronary ischaemia in acute endocarditis is usually due to pre-existing coronary disease or occasionally as a result of embolism from vegetations. A 68 year old man with known mixed aortic valve disease presented with a four week history of progressive exertional angina, which became unstable. He was apyrexial with no peripheral signs of endocarditis. Three sets of blood cultures were negative. Transthoracic echocardiography with suboptimal windows confirmed moderate mixed aortic valve disease. Marked reversible ST segment depression with angina recurred at rest. Aortography showed severe aortic regurgitation with a distorted aortic root. Coronary angiography showed severe proximal narrowing of the left anterior descending and circumflex arteries with an unusual long and tapering contour. Emergency surgery revealed a large anterior aortic root abscess which had destroyed the left and right coronary cusps. Aortic root abscess and other rare causes of extrinsic coronary compression are discussed.

Multifocal cardiac leiomyosarcoma. Diagnosis and surveillance by transoesophageal echocardiography and contrast enhanced cardiovascular magnetic resonance.

Primary cardiac sarcomas are rare and typically undergo aggressive local spread. There is no reliable definitive treatment, although radical surgical resection can provide palliation in the medium term. A case of a pleomorphic leiomyosarcoma with dramatic images is presented. The relative usefulness of transoesophageal echocardiography and cardiovascular magnetic resonance imaging to define the extent of tumour involvement, allowing planning of treatment, is demonstrated.

Does cytosine-thymine-guanine (CTG) expansion size predict cardiac events and electrocardiographic progression in myotonic dystrophy?

OBJECTIVE: To assess whether the size of the cytosine-thymine-guanine (CTG) expansion mutation in myotonic dystrophy predicts progression of conduction system disease and cardiac events. DESIGN: Longitudinal study involving ECG and clinical follow up over (mean (SD)) 4.8 (1.8) and 6.2 (1.9) years, respectively, of patients stratified by CTG expansion size (E0 to E4). PATIENTS: 73 adult patients under annual review in a regional myotonic dystrophy clinic. Patients were grouped into E0/E1 (n = 25), E2 (n = 34), and E3/E4 (n = 14). RESULTS: The proportion of patients with a QRS complex > 100 ms at baseline increased with the size of the CTG expansion (EO/E1, 4%; E2, 12%; E3/E4, 36%; p = 0.02). This trend was more pronounced at follow up (E0/E1, 4%; E2, 21%; E3/E4, 57%; p = 0.0004). The rate of widening of the QRS complex (ms/year) was similarly related to the size of the mutation (EO/E1, 0.4 (1.3); E2, 1.4 (2.5); E3/E4, 1.5 (1.6); p = 0.04). First degree atrioventricular block was present in 23% of patients at baseline and 34% at follow up, with no significant relation to expansion size. Seven patients suffered a cardiac event during follow up (sudden death in two, permanent pacemaker insertion in three, chronic atrial arrhythmia in two), of whom six were in CTG expansion group E2 or greater. Patients who experienced a cardiac event during follow up had more rapid rates of PR interval increase (9.9 (11.1) v 1.6 (2.9) ms/year; p = 0.008) and a trend to greater QRS complex widening (3.6 (4.5) v 0.9 (1.5) ms/year; p = 0.06) than those who did not. CONCLUSIONS: Larger CTG expansions are associated with a higher rate of conduction disease progression and a trend to increased risk of cardiac events in myotonic dystrophy.

Transthoracic echocardiography using second harmonic imaging with Valsalva manoeuvre for the detection of right to left shunts.

AIMS: To assess transthoracic echocardiography (TTE) using second harmonic imaging with Valsalva manoeuvre compared to transesophageal echocardiography (TEE) for the diagnosis of right to left cardiac and pulmonary shunts. METHODS AND RESULTS: One hundred and ten patients referred for TEE underwent TTE with bubble contrast. Bubbles in the left atrium within three cardiac cycles were considered diagnostic for a patent foramen ovale (PFO) and later as a pulmonary shunt. Greater than 20 bubbles in the left atrium was considered a large shunt and less than 20 a small shunt. TEE was performed immediately afterwards and read blinded to the TTE results. Pick-up rates were similar with 19 TEE positive (13 PFO) and 18 TTE positive (14 PFO) patients. There were five TEE positive/TTE negative cases who had significantly poorer TTE image quality score (2.7 +/- 0.8 vs 1.9 +/- 0.6, p < 0.05). There were six TEE negative/TTE positive cases, two cases requiring Valsalva manoeuvre to become positive. The Valsalva manoeuvre significantly increased the number of bubbles shunting (10 +/- 11 vs 20 +/- 19, p < 0.005). CONCLUSION: TTE with Valsalva manoeuvre is as good as TEE in diagnosing shunts. Valsalva manoeuvre increases the size of shunt. Both techniques produce false negative results.