Landscape Utilisation, Animal Behaviour and Hendra Virus Risk.

Hendra virus causes sporadic fatal disease in horses and humans in eastern Australia. Pteropid bats (flying-foxes) are the natural host of the virus. The mode of flying-fox to horse transmission remains unclear, but oro-nasal contact with flying-fox urine, faeces or saliva is the most plausible. We used GPS data logger technology to explore the landscape utilisation of black flying-foxes and horses to gain new insight into equine exposure risk. Flying-fox foraging was repetitious, with individuals returning night after night to the same location. There was a preference for fragmented arboreal landscape and non-native plant species, resulting in increased flying-fox activity around rural infrastructure. Our preliminary equine data logger study identified significant variation between diurnal and nocturnal grazing behaviour that, combined with the observed flying-fox foraging behaviour, could contribute to Hendra virus exposure risk. While we found no significant risk-exposing difference in individual horse movement behaviour in this study, the prospect warrants further investigation, as does the broader role of animal behaviour and landscape utilisation on the transmission dynamics of Hendra virus.

Factors associated with recurrent stroke and recanalization in patients presenting with isolated symptomatic carotid occlusion.

BACKGROUND AND PURPOSE: Patients with symptomatic internal carotid artery (ICA) occlusion constitute a small proportion of stroke/transient ischaemic attack patients who are at increased risk of early stroke recurrence and poor outcome. The optimal medical treatment for patients with symptomatic ICA occlusion who are ineligible for thrombolysis or thrombectomy is unknown. METHODS: Consecutive patients presenting at a single center with newly diagnosed symptomatic ICA occlusion (not involving the circle of Willis) were retrospectively reviewed. Those treated with intravenous thrombolysis or intra-arterial thrombolysis/thrombectomy were excluded. Patients were divided into two groups based on whether they experienced recurrent in-hospital stroke. RESULTS: The selected study population (n = 33) represented a small (20.4%) proportion of all newly symptomatic carotid occlusions, who nevertheless had an elevated risk of recurrent stroke during admission (24.2%). Of the variables examined (age, gender, admission National Institutes of Health Stroke Scale score, vascular risk factors, atrial fibrillation, prior stroke/transient ischaemic attack and anticoagulation within 48 h of presentation), only anticoagulation was significantly associated with a lower risk of in-hospital recurrent stroke. Anticoagulated patients showed a decreased incidence of stroke recurrence within the first week (6.7% vs. 38.9%, P = 0.032) and fewer strokes or deaths at 1 month (13.3% vs. 47.1%, P = 0.040). Hemorrhagic transformation was not observed in any patient. On follow-up imaging, ICA recanalization was significantly more frequent in anticoagulated patients (46.2% vs. 9.1%, P = 0.047). CONCLUSION: Patients with newly diagnosed symptomatic ICA occlusion (not involving the circle of Willis) represent a small but high risk subgroup of patients with carotid occlusion. Early anticoagulation was associated with fewer recurrent strokes and increased ICA recanalization. Larger scale prospective studies may be justified.

Avian influenza in Australia: a summary of 5 years of wild bird surveillance.

BACKGROUND: Avian influenza viruses (AIVs) are found worldwide in numerous bird species, causing significant disease in gallinaceous poultry and occasionally other species. Surveillance of wild bird reservoirs provides an opportunity to add to the understanding of the epidemiology of AIVs. METHODS: This study examined key findings from the National Avian Influenza Wild Bird Surveillance Program over a 5-year period (July 2007-June 2012), the main source of information on AIVs circulating in Australia. RESULTS: The overall proportion of birds that tested positive for influenza A via PCR was 1.9 ± 0.1%, with evidence of widespread exposure of Australian wild birds to most low pathogenic avian influenza (LPAI) subtypes (H1-13, H16). LPAI H5 subtypes were found to be dominant and widespread during this 5-year period. CONCLUSION: Given Australia's isolation, both geographically and ecologically, it is important for Australia not to assume that the epidemiology of AIV from other geographic regions applies here. Despite all previous highly pathogenic avian influenza outbreaks in Australian poultry being attributed to H7 subtypes, widespread detection of H5 subtypes in wild birds may represent an ongoing risk to the Australian poultry industry.

Survival of hendra virus in the environment: modelling the effect of temperature.

Hendra virus (HeV), a highly pathogenic zoonotic paramyxovirus recently emerged from bats, is a major concern to the horse industry in Australia. Previous research has shown that higher temperatures led to lower virus survival rates in the laboratory. We develop a model of survival of HeV in the environment as influenced by temperature. We used 20 years of daily temperature at six locations spanning the geographic range of reported HeV incidents to simulate the temporal and spatial impacts of temperature on HeV survival. At any location, simulated virus survival was greater in winter than in summer, and in any month of the year, survival was higher in higher latitudes. At any location, year-to-year variation in virus survival 24 h post-excretion was substantial and was as large as the difference between locations. Survival was higher in microhabitats with lower than ambient temperature, and when environmental exposure was shorter. The within-year pattern of virus survival mirrored the cumulative within-year occurrence of reported HeV cases, although there were no overall differences in survival in HeV case years and non-case years. The model examines the effect of temperature in isolation; actual virus survivability will reflect the effect of additional environmental factors.

Epidemiology and neuropsychiatric manifestations of Young Onset Parkinson's Disease in the United States.

BACKGROUND: To determine the demographic distribution of Young Onset Parkinson's Disease (YOPD) in the United States and to quantify the burden of neuropsychiatric disease manifestations. METHODS: Cross sectional study of 3,459,986 disabled Americans, aged 30-54, who were receiving Medicare benefits in the year 2005. We calculated race and sex distributions of YOPD and used logistic regression to compare the likelihood of common and uncommon psychiatric disorders between beneficiaries with YOPD and the general disability beneficiary population, adjusting for race, age, and sex. RESULTS: We identified 14,354 Medicare beneficiaries with YOPD (prevalence = 414.9 per 100,000 disabled Americans). White men comprised the majority of cases (48.9%), followed by White women (34.7%), Black men (6.8%), Black women (5.0%), Hispanic men (2.4%), and Hispanic women (1.2%). Asian men (0.6%) and Asian women (0.4%) were the least common race-sex pairs with a YOPD diagnosis in this population (chi square, p < 0.001). Compared to the general population of medically disabled Americans, those with YOPD were more likely to receive medical care for depression (OR: 1.89, 1.83-1.95), dementia (OR: 7.73, 7.38-8.09), substance abuse/dependence (OR: 3.00, 2.99-3.01), and were more likely to be hospitalized for psychosis (OR: 3.36, 3.19-3.53), personality/impulse control disorders (OR: 4.56, 3.28-6.34), and psychosocial dysfunction (OR: 3.85, 2.89-5.14). CONCLUSIONS: Young Onset Parkinson's Disease is most common among white males in our study population. Psychiatric illness, addiction, and cognitive impairment are more common in YOPD than in the general population of disabled Medicare beneficiaries. These may be key disabling factors in YOPD.

Significant features of the epidemiology of equine influenza in Queensland, Australia, 2007.

An outbreak of equine influenza (EI) caused by influenza A H3N8 subtype virus occurred in the Australian states of Queensland and New South Wales in August 2007. Infection in the Australian horse population was associated with the introduction of infection by horses from overseas. The first case of EI in Queensland was detected on 25 August 2007 at an equestrian sporting event. Infection subsequently spread locally and to other clusters through horse movements prior to the implementation of an official standstill. There were five main clusters of infected properties during this outbreak and several outliers, which were investigated to find the potential mechanism of disease spread. To contain the outbreak, Queensland was divided into infection status zones, with different movement controls applied to each zone. Vaccination was implemented strategically in infected areas and within horse subpopulations. Control and eventual eradication of EI from Queensland was achieved through a combination of quarantine, biosecurity measures, movement control, rapid diagnostic testing and vaccination.

Evaluating the effectiveness of the response to equine influenza in the Australian outbreak and the potential role of early vaccination.

OBJECTIVE: To use modelling and epidemiological analyses to assess the effectiveness of control strategies employed during the equine influenza outbreak and determine if early vaccination might have had a beneficial effect. METHODS: Transmission of infection was modelled using stochastic, spatial simulation, based on data from 16 regions in New South Wales and Queensland over the first month of the outbreak. RESULTS: The model accurately represented the spread of infection in both space and time and showed that vaccination strategies would have reduced new infections by ∼60% and reduced the size of the infected area by 8-9%, compared to the non-vaccination baseline. CONCLUSION: When used in conjunction with biosecurity measures and movement controls, early vaccination could play an important role in the containment and eradication of equine influenza.

Evaluating the effectiveness of early vaccination in the control and eradication of equine influenza--a modelling approach.

In August 2007, Australia which had previously been free of equine influenza, experienced a large outbreak that lasted approximately 4 months before it was eradicated. The outbreak required a significant national response by government and the horse industries. The main components of the response were movement controls, biosecurity measures, risk-based zoning and, subsequently, vaccination to contain the outbreak. Although not initially used, vaccination became a key element in the eradication program, with approximately 140000 horses vaccinated. Vaccination is recognised as a valuable tool for managing EI in endemically infected countries but there is little experience using it in situations where the objective is disease eradication. Vaccination was undoubtedly an important factor in 2007 as it enabled movements of some horses and associated industry activities to recommence. However, its contribution to containment and eradication is less clear. A premises-level equine influenza model, based on an epidemiological analysis of the 2007 outbreak, was developed to evaluate effectiveness of the mitigation strategies used and to investigate whether vaccination, if applied earlier, would have had an effect on the course of the outbreak. The results indicate that early use of strategic vaccination could have significantly reduced the size of the outbreak. The four vaccination strategies evaluated had, by 1 month into the control program, reduced the number of new infections on average by 60% and the size of the infected area by 8-9%. If resources are limited, a 1 km suppressive ring vaccination around infected premises gave the best results, but with greater vaccination capacity, a 3 km ring vaccination was the most effective strategy. The findings suggest that as well as reducing clinical and economic impacts, vaccination when used with biosecurity measures and movement controls could play an important role in the containment and eradication of equine influenza.

Recurrent variceal bleeding in a young woman.

Congenital hepatic fibrosis is an uncommon fibrocystic disorder affecting the intrahepatic bile ducts. It has autosomal recessive inheritance. The main consequence of this condition is portal hypertension and it is often misdiagnosed as cirrhosis. Patients with congenital hepatic fibrosis usually present during childhood or early adolescence with oesophageal variceal bleeding. Portosystemic shunt surgery is the treatment of choice for these patients as the risk of postoperative hepatic encephalopathy is low. We report a patient with congenital hepatic fibrosis who presented with oesophageal variceal bleeding at the age of 16 years, initially misdiagnosed as having cryptogenic liver cirrhosis. The patient experienced two further episodes of oesophageal variceal bleeding in subsequent years. She eventually underwent portosystemic shunt surgery. One year after the operation, the shunt remained patent on Doppler ultrasonography, and there had been no further episodes of variceal bleeding post-surgery.

Epigastric pain in a patient with neurofibromatosis type 1.

Patients with neurofibromatosis type 1 are at increased risk of developing carcinoid tumours of the duodenum, particularly in the ampulla of Vater. Aggressive surgery with pancreatoduodenectomy is recommended for all ampullary carcinoid tumours because of their propensity to metastasise. We report a case of a 43-year-old woman with neurofibromatosis type 1, who presented with recurrent epigastric pain for 15 months. Evaluation using magnetic resonance cholangiopancreatography and side-viewing duodenoscopy revealed a submucosal tumour at the ampulla of Vater causing pancreatobiliary ductal obstruction and dilation. The ampullary tumour was overlooked initially by forward-viewing endoscopy. The patient subsequently underwent pancreatoduodenectomy. Histological examination of the surgically resected specimen confirmed the presence of a carcinoid tumour, with metastasis to peri-pancreatic lymph nodes. She remained asymptomatic 10 months after surgery.

The impact of a monthly rest day on avian influenza virus isolation rates in retail live poultry markets in Hong Kong.

Retail live poultry markets (LPMs) may act as a reservoir of avian influenza viruses (AIV). In this study we test the hypothesis that a rest day in the LPMs where the stalls are completely emptied of poultry, cleansed, and restocked will reduce the isolation rates of avian influenza viruses. The isolation rate of H9N2 subtype viruses from chicken was significantly lower after the rest day than prior to it, indicating its impact in reducing transmission. In contrast, Newcastle disease virus (NDV) isolation rates appear unaffected by this intervention, possibly reflecting differences in herd immunity or virus transmission dynamics.

An update on avian influenza in Hong Kong 2002.

An outbreak of highly pathogenic avian influenza caused by multiple genotypes of H5N1 virus occurred in Hong Kong, commencing in January 2002. Infection in local chicken farms was preceded by the detection of virus in multiple retail markets and the main poultry wholesale market. The first case of this disease on a local farm was detected on February 1, 2002. By February 9, 2002, 15 farms were infected, and by late March a total of 22 infected farms had been identified. Three main clusters of infected farms were seen, suggesting multiple incursions of virus, and subsequent limited lateral spread to neighboring firms. Control of this disease has been effected through a combination of quarantine, tightening of biosecurity measures, and depopulation of infected and contact farms. About 950,000 birds have been destroyed. Vaccination using a killed H5 vaccine was introduced in April 2002 to farms in one zone where infection has persisted. None of the viruses isolated contained the internal genes found in the 1997 H5N1 virus.

Three-day lansoprazole quadruple therapy for Helicobacter pylori-positive duodenal ulcers: a randomized controlled study.

AIM: To compare the efficacy and tolerability of a 3-day quadruple therapy with a standard 7-day triple therapy in eradicating Helicobacter pylori infection and healing duodenal ulcers. METHODS: Patients with H. pylori-positive duodenal ulcers were randomized to receive either lansoprazole 30 mg, clarithromycin 500 mg, and metronidazole 400 mg twice daily for 7 days (LCM-7) or lansoprazole 30 mg, clarithromycin 500 mg, metronidazole 400 mg, and bismuth subcitrate 240 mg twice daily for 3 days (LCMB-3). No pre- or post-treatment acid suppression was used. Follow-up endoscopy was performed at week 6. RESULTS: A total of 118 patients were recruited. Sixty patients in the LCM-7 group and 53 patients in the LCMB-3 group returned for endoscopy. Intention-to-treat eradication rates were 87% and 86% (P=0.94) and per protocol eradication rates were 87% and 94% (P=0.29) in the LCM-7 and LCMB-3 groups, respectively. Per protocol and intention-to-treat ulcer healing rates were 98% and 98% in LCM-7 and 100% and 91% in LCMB-3, respectively. There were no significant differences in efficacy in relation to the initial metronidazole and clarithromycin susceptibility. Significant reduction in the duration of side-effects was found in the LCMB-3 group. CONCLUSION: The 3-day quadruple therapy is highly effective, better tolerated and can be considered as a first-line therapy in duodenal ulcer management.

Incidence of gastroesophageal malignancy in patients with dyspepsia in Hong Kong: implications for screening strategies.

BACKGROUND: A "test-and-treat" strategy for H pylori infection has been recommended in Europe and North America as safe and cost-effective for management of patients with dyspepsia. The primary aim of this study was to determine the frequency of gastroesophageal cancer in 2 groups of patients with dyspepsia: those 45 years of age or younger without "alarm" symptoms (low-risk group) and patients over 45 years of age or any patient with "alarm" symptoms (high-risk group). A secondary aim was to determine the frequency of gastric cancer among patients in the low-risk group with or without a positive serology for H pylori. METHODS: Patients with persistent dyspepsia were recruited from 4 regional hospitals in Hong Kong. Those in the low-risk group were evaluated for H pylori by using a whole blood serology test; they underwent endoscopy within 1 week. Those in the high-risk group and those taking nonsteroidal anti-inflammatory drugs (NSAIDs) underwent endoscopy promptly. Alarm symptoms were as follows: weight loss (10 or more pounds over 8 weeks), recurrent vomiting, dysphagia, bleeding, or anemia. RESULTS: Of 2627 patients enrolled, 1017 were in the low-risk group and 1610 in the high-risk group. Twenty-three patients (0.9%) had gastroesophageal cancers (20 gastric, 3 esophageal). Four patients with cancer (17.4%) were in the low-risk group (3 gastric, 1 esophageal); all except the patient with esophageal cancer had a positive serology test. In the high-risk group, 19 patients had cancer (17 gastric, 2 esophageal). CONCLUSION: Gastric cancer is relatively frequent among young patients with dyspepsia who have no alarm features in Hong Kong. This finding raises concerns as to the safety of the "test-and-treat" strategy for the management of patients with dyspepsia in Asia.

Economic analysis of four triple regimens for the treatment of Helicobacter pylori-related peptic ulcer disease in in-patient and out-patient settings in Hong Kong.

BACKGROUND: One-week triple regimens have been shown to be effective for the treatment of Helicobacter pylori-related peptic ulcer disease. AIM: To conduct an economic analysis of four triple regimens for the treatment of H. pylori-related peptic ulcer disease from the perspective of a public health organization in Hong Kong. METHODS: Records of 200 patients with H. pylori-related peptic ulcer disease, who had previously participated in a randomized comparison of ranitidine bismuth citrate (RBC) with amoxicillin and clarithromycin (RAC), omeprazole with amoxicillin and clarithromycin (OAC), RBC with metronidazole and tetracycline (RMT), or, colloidal bismuth subcitrate with metronidazole and tetracycline (BMT) in either in-patient or out-patient setting were reviewed. RESULTS: Fifty patients were excluded because of incomplete documentation or lack of peptic ulcer. In the out-patient group (n=72), the median direct costs of the RAC group (HK $ 5094) were lower those of the BMT (HK $ 5400), RMT (HK $ 5394), or OAC (HK $ 5440) groups, but the difference was significant only between the RAC and BMT groups (P < 0.05). In the in-patient group (n=78), the median direct costs of the RMT group (HK $ 8524) were significantly lower than those of the OAC (HK $ 13 871) and RAC (HK $ 12 092) groups (P < 0.05), but were similar to those of the BMT group (HK $ 8758). CONCLUSIONS: RAC and RMT are the least costly regimens for out-patient and in-patient treatment, respectively, of H. pylori-related peptic ulcer disease in Hong Kong.

beta-thalassemia intermedia caused by compound heterozygosity for Hb Malay (beta codon 19 AAC-->AGC; asn-->Ser) and codons 41/42 (-CTTT) beta(0)-thalassemia mutation.

We report a case of beta-thalassemia intermedia caused by compound heterozygosity for hemoglobin (Hb) Malay and codon 41/42 (-CTTT) beta(0)-thalassemia mutation in a 38-year-old Chinese woman. This patient has long-standing anemia with a baseline Hb level of around 70 g/L. She worked as a full-time cashier and had not required regular blood transfusions. Nevertheless, she had splenomegaly necessitating splenectomy, cholelithiasis, and iron overload. This case illustrates the varied phenotypic expression associated with compound heterozygosity for Hb Malay and other beta-thalassemia mutations. Since Hb Malay migrates as Hb A on electrophoresis and chromatography, this variant Hb mutation ought to be included in the differential diagnosis for beta-thalassemia major or intermedia patients of Southeast Asian descent who are reported to have Hb A on the basis of Hb analysis. The possible presence of this mutation should also be considered in appropriate cases for genetic counseling in couples at risk of conceiving fetuses with beta-thalassemia major or intermedia.

One-week ranitidine bismuth citrate versus colloidal bismuth subcitrate-based anti-Helicobacter triple therapy: a prospective randomized controlled trial.

OBJECTIVE: The efficacy of 1 wk bismuth triple therapy is adversely influenced by the presence of metronidazole resistance. In vitro studies suggest that ranitidine bismuth citrate (RBC) plus metronidazole exhibit synergistic activity against metronidazole resistant strains of Helicobacter pylori (H. pylori). Whether this confers a superior clinical efficacy remains unproven. This study compared the efficacy of RBC-based triple therapy with bismuth triple therapy in eradication of H. pylori. METHODS: Patients with H. pylori-related ulcer disease or gastritis were randomized to receive either 400/mg of RBC twice daily plus 400/mg of metronidazole and 500/mg of tetracycline four times daily for 1 wk (RMT) or 120/mg of colloidal bismuth subcitrate, 400/mg of metronidazole, and 500/mg of tetracycline, all given four times daily for 1 wk (BMT). Metronidazole susceptibility was determined by the E-test and pretreatment resistance was defined as minimum inhibitory concentration > or = 32/mg/L. RESULTS: Of 100 consecutive patients randomized, two patients were lost to follow-up in each group. Forty-three of 85 (51%) H. pylori isolates were metronidazole resistant. Per-protocol cure rate for RMT and BMT was 40 of 41 (98%) and 37 of 44 (84%), respectively (p = 0.058). Intent-to-treat cure rate for RMT and BMT was 46 of 50 and 41 of 50, respectively (92% vs 82%, p = 0.23). A significantly higher eradication of metronidazole resistant H. pylori was observed in the RMT group (25 of 25, 100%) than in the BMT group (12 of 16, 75%), (p = 0.018). Side effects observed in the two treatment groups were comparable. CONCLUSIONS: One week of RBC triple therapy with metronidazole and tetracycline is an effective anti-Helicobacter therapy. This regimen is more appropriate in areas of high prevalence of metronidazole resistance.

Undiagnosed acute myocardial infarction in the accident and emergency department: reasons and implications.

Because acute myocardial infarction causes significant morbidity and mortality, a correct diagnosis in the accident and emergency department is important so that early treatment including thrombolytic therapy can be given. The aim of this study was to evaluate the reasons for missed diagnosis of acute myocardial infarction in the accident and emergency department, and the implications. All patients admitted to our coronary care unit in 1995 with the confirmed diagnosis of acute myocardial infarction were analysed retrospectively. The demographic data, clinical profiles, diagnosis made at the accident and emergency department and feasibility of thrombolytic therapy were assessed. Analysis of the electrocardiography by the accident and emergency department doctor and the coronary care unit doctor were also compared. Forty-three out of 159 patients (27.0%) with acute myocardial infarction were missed in the accident and emergency department. The diagnoses made were mostly angina or chest pain. Absence of chest pain (25.6%) [vs. 10.2% in correct diagnosis group, p < 0.05] and lack of ST elevation in electrocardiograph (62.8%) [vs. 18.1% in correct diagnosis group, p < 0.0001] were the main predisposing factors for missed diagnosis. Because of missed diagnosis, only 25.6% (vs. 67.2% in correct diagnosis group, p < 0.01) of patients were admitted to the coronary care unit. About one-third (34.9%) of missed diagnosis patients (vs. 6.0% in correct diagnosis, p < 0.01) did not receive thrombolytic therapy because of delayed diagnosis. In the missed diagnosis group, 34.8% of them might be avoidable, if electrocardiogram interpretation was more accurate. More education and training of the involved medical personnel might improve the overall situation.