The impact of integrating rabbit haemorrhagic disease virus (K5) release with pindone baiting on wild rabbit populations.

Several conventional and recently available tools are available for an integrated control of European rabbits in Australia. We quantified the impact of the release of rabbit haemorrhagic disease virus K5 (RHDV K5, hereafter K5) and pindone (2-pivalyl-1,3-indandione) baiting at 13 sites within Cudlee Creek fire scar in the Adelaide Hills, South Australia. K5 release was followed by pindone baiting between December 2021 and March 2022; the application of both control methods followed industry best practice. We counted rabbits using spotlights before and after the application of both control methods. Fly samples and livers from dead rabbits were collected to track K5 transmission within and between sites, and to detect the natural circulation of rabbit haemorrhagic disease virus 2 (RHDV2). K5 release had minimal impact on rabbit populations, with treated populations increasing by a mean of 65.5% at 14 days post-release and 27.9% at 77 days post-K5 release across all sites, comparable to the changes at control sites. K5 detection in flies up to 77 days post its release, and its detection in rabbit livers, demonstrates that it can survive and transmit in the environment for prolonged periods and that it can lethally infect some rabbits. This limited impact of K5 is consistent with previous studies and may be explained by pre-existing RHDV/RHDV2 immunity in the target populations or the presence of young rabbits with natural innate RHDV immunity. The detection of K5 in flies from control sites demonstrates that it was vectored beyond its release location. A reduction in rabbit counts post-pindone baiting was observed at most treatment sites, with a mean population reduction of 36.6% across all sites. Landholders need to carefully and strategically plan their integrated rabbit control programmes. Not all combinations of controls, even if theoretically logical, achieve meaningful outcomes for rabbit management.

Bayesian evaluation of temporal changes in sensitivity and specificity of three serological tests for multiple circulating strains of rabbit haemorrhagic disease virus.

Competition and indirect ELISAs are currently being used to monitor rabbit haemorrhagic disease viruses (RHDV1 and RHDV2) in rabbits worldwide. Temporal changes in the sensitivity (Se) and specificity (Sp) of RHDV1 competition-ELISA (cELISA1), RHDV2 competition-ELISA (cELISA2), and RHDV1 Immunoglobulin G (IgG1) ELISA, were investigated using Bayesian Latent Class models (BCLM) in the Australian wild rabbit population where both viruses circulate simultaneously and a long-term serological dataset exists. When cELISA1 was compared to IgG1 ELISA, the Se of cELISA1 improved while the Sp of IgG1 ELISA declined over the 2011-21. This corresponded with a decline in the true RHDV1 prevalence in 2018-21, suggesting that a large proportion of RHDV1 exposed rabbits survived the introduction and dominance of RHDV2 up to approximately 2017/2018, after which they died and were not replaced. The Se and Sp estimates for 2014-15 for both cELISA1 and IgG1 ELISA, and the true prevalence when analysing all three tests together were similar to those obtained from the analysis of cELISA1/IgG1 ELISA. The same was also true for the Se and Sp of cELISA2 and IgG1 ELISA estimates from 2018 onwards. This suggests that RHDV1 was the dominant infection type in 2014-15, but RHDV2 was the dominant infection type in 2018-21. Further, the increase in Se of cELISA2 and the low Sp of IgG1 ELISA in the cELISA2/IgG1 ELISA analysis, compared to the Se of cELISA2 and Sp of IgG1 ELISA when analysing all three tests together suggests that the underlying infection status was more influenced by RHDV2 and that the higher Se of IgG1 ELISA is due to cross-reaction of RHDV2 antibodies on IgG1 ELISA. The true prevalence data suggest that RHDV2 exposure peaked in 2017. Our findings show that test characteristics changed in response to the changing virus prevalences over time. IgG1 ELISA, currently having a high Se, should be used to monitor both viruses and will perform better than both cELISAs.

Utilizing Molecular Epidemiology and Citizen Science for the Surveillance of Lagoviruses in Australia.

Australia has multiple lagoviruses with differing pathogenicity. The circulation of these viruses was traditionally determined through opportunistic sampling events. In the lead up to the nationwide release of RHDVa-K5 (GI.1aP-GI.1a) in 2017, an existing citizen science program, RabbitScan, was augmented to allow members of the public to submit samples collected from dead leporids for lagovirus testing. This study describes the information obtained from the increased number of leporid samples received between 2015 and 2022 and focuses on the recent epidemiological interactions and evolutionary trajectory of circulating lagoviruses in Australia between October 2020 and December 2022. A total of 2771 samples were tested from January 2015 to December 2022, of which 1643 were lagovirus-positive. Notable changes in the distribution of lagovirus variants were observed, predominantly in Western Australia, where RHDV2-4c (GI.4cP-GI.2) was detected again in 2021 after initially being reported to be present in 2018. Interestingly, we found evidence that the deliberately released RHDVa-K5 was able to establish and circulate in wild rabbit populations in WA. Overall, the incorporation of citizen science approaches proved to be a cost-efficient method to increase the sampling area and enable an in-depth analysis of lagovirus distribution, genetic diversity, and interactions. The maintenance of such programs is essential to enable continued investigations of the critical parameters affecting the biocontrol of feral rabbit populations in Australia, as well as to enable the detection of any potential future incursions.

Quantifying resistance to myxomatosis in wild rabbits produces novel evolutionary insights.

Wild rabbits in Australia developed genetic resistance to the myxoma virus, which was introduced as a biological control agent. However, little is known about the rate at which this evolutionary change occurred. We collated data from challenge trials that estimated rabbit resistance to myxomatosis in Australia and expressed resistance on a continuous scale, enabling trends in its development to be assessed over 45 years up to 1995. Resistance initially increased rapidly, followed by a plateau lasting ten years, before a second rapid increase occurred associated with the introduction of European rabbit fleas as myxoma virus vectors. By contrast, in the United Kingdom, where rabbit flea vectors were already present when the myxoma virus initially spread, resistance developed more slowly. No estimates of rabbit resistance to myxomatosis have been made for almost 30 years, despite other highly lethal rabbit pathogens becoming established worldwide. Continued testing of wild-caught rabbits in Australia to determine current levels of resistance to myxomatosis is recommended to assess its current effectiveness for managing pest rabbits. Given the economic and environmental significance of invasive rabbits, it would be remiss to manage such biological resources and ecosystem services poorly.

Timing of Surgery and Pre-operative Physiological Parameters as Clinical Predictors of Surgical Outcomes in Traumatic Subaxial Cervical Spine Fractures and Dislocations.

Objective To evaluate the risk factors and outcomes in patients surgically treated for subaxial cervical spine injuries with respect of the timing of surgery and preoperative physiological parameters of the patient. Methods 26 patients with sub-axial cervical spine fractures and dislocations were enrolled. Demographic data of patients, appropriate radiological investigation, and physiological parameters like respiratory rate, blood pressure, heart rate, PaO2 and ASIA impairment scale were documented. They were divided pre-operatively into 2 groups. Group U with patients having abnormal physiological parameters and Group S including patients having physiological parameters within normal range. They were further subdivided into early and late groups according to the timing of surgery as U early , U late, S early and S late . All the patients were called for follow-up at 1, 6 and 12 months. Results 56 percent of patients in Group S had neurological improvement by one ASIA grade and a good outcome irrespective of the timing of surgery. Patients in Group U having unstable physiological parameters and undergoing early surgical intervention had poor outcomes. Conclusion This study concludes that early surgical intervention in physiologically unstable patients had a strong association as a risk factor in the final outcome of the patients in terms of mortality and morbidity. Also, no positive association of improvement in physiologically stable patients with respect to the timing of surgery could be established.

Optimising the Delivery of RHDV to Rabbits for Biocontrol: An Experimental Evaluation of Two Novel Methods of Virus Delivery.

Rabbit haemorrhagic disease virus (RHDV) is established as a landscape-scale biocontrol that assists the management of invasive European rabbits and their impacts in both Australia and New Zealand. In addition to this, it is also available to land managers to augment rabbit control efforts at a local scale. However, current methods of deploying RHDV to rabbits that rely on the consumption of virus-treated baits can be problematic as rabbits are reluctant to consume bait when there is abundant, green, protein-rich feed available. We ran a suite of interrupted time-series experiments to compare the duration of infectivity of two conventional (carrot and oat baits) and two novel (meat bait and soil burrow spray) methods of deploying RHDV to rabbits. All methods effectively killed exposed rabbits. Soil burrow spray and carrot baits resulted in infection and mortality out to 5 days post their deployment in the field, and meat baits caused infection out to 10 days post their deployment. In contrast, oat baits continued to infect and kill exposed rabbits out to 20 days post deployment. Molecular assays demonstrated high viral loads in deployed baits beyond the duration for which they were infectious or lethal to rabbits. Based on our results, we suggest that the drying of meat baits may create a barrier to effective transmission of RHDV by adult flies within 10 days. We therefore hypothesise that fly larvae production and development on infected tissues is critical to prolonged viral transmission from meat baits, and similarly from carcasses of RHDV mortalities, via mechanical fly vectors. Our study demonstrates that meat baits and soil spray could provide additional virus deployment options that remove the need for rabbits to consume baits at times when they are reluctant to do so.

Timing of Surgery and Pre-operative Physiological Parameters as Clinical Predictors of Surgical Outcomes in Traumatic Subaxial Cervical Spine Fractures and Dislocations / Momento da cirurgia e parâmetros fisiológicos pré-operatórios como fatores preditivos clínicos de desfechos cirúrgicos em fraturas e luxações traumáticas subaxiais da coluna cervical

Abstract Objective To evaluate the risk factors and outcomes in patients surgically treated for subaxial cervical spine injuries with respect of the timing of surgery and preoperative physiological parameters of the patient. Methods 26 patients with sub-axial cervical spine fractures and dislocations were enrolled. Demographic data of patients, appropriate radiological investigation, and physiological parameters like respiratory rate, blood pressure, heart rate, PaO2 and ASIA impairment scale were documented. They were divided pre-operatively into 2 groups. Group U with patients having abnormal physiological parameters and Group S including patients having physiological parameters within normal range. They were further subdivided into early and late groups according to the timing of surgery as Uearly, Ulate, Searly and Slate. All the patients were called for follow-up at 1, 6 and 12 months. Results 56 percent of patients in Group S had neurological improvement by one ASIA grade and a good outcome irrespective of the timing of surgery. Patients in Group U having unstable physiological parameters and undergoing early surgical intervention had poor outcomes. Conclusion This study concludes that early surgical intervention in physiologically unstable patients had a strong association as a risk factor in the final outcome of the patients in terms of mortality and morbidity. Also, no positive association of improvement in physiologically stable patients with respect to the timing of surgery could be established.

Resumo Objetivo Avaliar os fatores de risco e os desfechos em indivíduos submetidos ao tratamento cirúrgico de lesões subaxiais da coluna cervical em relação ao momento da cirurgia e aos parâmetros fisiológicos pré-operatórios dos pacientes. Métodos O estudo incluiu 26 pacientes com fraturas e luxações subaxiais da coluna cervical. Dados demográficos, investigação radiológica apropriada e parâmetros fisiológicos, como frequência respiratória, pressão arterial, frequência cardíaca, pressão parcial de oxigênio (PaO2) e escalas de disfunção da American Spine Injury Association (ASIA), foram documentados. No período pré-operatório, os pacientes foram divididos em dois grupos. O grupo instável (I) continha pacientes com parâmetros fisiológicos anormais e o grupo estável (E) era composto por pacientes com parâmetros fisiológicos dentro da faixa de normalidade. Os pacientes foram ainda subdivididos em grupos de tratamento precoce e tardio de acordo com o momento da cirurgia como Iprecoce, Itardio, Eprecoce e Etardio. Todos os pacientes foram chamados para consultas de acompanhamento em 1, 6 e 12 meses. Resultados Cinquenta e seis por cento dos pacientes do grupo E apresentaram melhora neurológica em um grau ASIA e desfecho bom independentemente do momento da cirurgia. Os desfechos em pacientes do grupo I com parâmetros fisiológicos instáveis e submetidos à intervenção cirúrgica precoce foram maus. Conclusão Este estudo conclui que a intervenção cirúrgica precoce em pacientes com instabilidade fisiológica teve forte associação como fator de risco no desfecho final em termos de mortalidade e morbidade. Além disso, não foi possível estabelecer nenhuma associação positiva de melhora em pacientes com estabilidade fisiológica em relação ao momento da cirurgia.

Sustained Impact of RHDV2 on Wild Rabbit Populations across Australia Eight Years after Its Initial Detection.

Following the arrival of rabbit haemorrhagic disease virus 2 (RHDV2) in Australia, average rabbit population abundances were reduced by 60% between 2014 and 2018 based on monitoring data acquired from 18 sites across Australia. During this period, as the seropositivity to RHDV2 increased, concurrent decreases were observed in the seroprevalence of both the previously circulating RHDV1 and RCVA, a benign endemic rabbit calicivirus. However, the detection of substantial RHDV1 seropositivity in juvenile rabbits suggested that infections were continuing to occur, ruling out the rapid extinction of this variant. Here we investigate whether the co-circulation of two pathogenic RHDV variants was sustained after 2018 and whether the initially observed impact on rabbit abundance was still maintained. We monitored rabbit abundance and seropositivity to RHDV2, RHDV1 and RCVA at six of the initial eighteen sites until the summer of 2022. We observed sustained suppression of rabbit abundance at five of the six sites, with the average population reduction across all six sites being 64%. Across all sites, average RHDV2 seroprevalence remained high, reaching 60-70% in adult rabbits and 30-40% in juvenile rabbits. In contrast, average RHDV1 seroprevalence declined to <3% in adult rabbits and 5-6% in juvenile rabbits. Although seropositivity continued to be detected in a low number of juvenile rabbits, it is unlikely that RHDV1 strains now play a major role in the regulation of rabbit abundance. In contrast, RCVA seropositivity appears to be reaching an equilibrium with that of RHDV2, with RCVA seroprevalence in the preceding quarter having a strong negative effect on RHDV2 seroprevalence and vice versa, suggesting ongoing co-circulation of these variants. These findings highlight the complex interactions between different calicivirus variants in free-living rabbit populations and demonstrate the changes in interactions over the course of the RHDV2 epizootic as it has moved towards endemicity. While it is encouraging from an Australian perspective to see sustained suppression of rabbit populations in the eight years following the arrival of RHDV2, it is likely that rabbit populations will eventually recover, as has been observed with previous rabbit pathogens.

Cross-protection, infection and case fatality rates in wild European rabbits experimentally challenged with different rabbit haemorrhagic disease viruses.

Rabbit haemorrhagic disease virus 2 (RHDV2) is now the dominant calicivirus circulating in wild rabbit populations in Australia. This study compared the infection and case fatality rates of RHDV2 and two RHDVs in wild rabbits, as well as their ability to overcome immunity to the respective other strains. Wild rabbits were allocated to groups either blindly or based on pre-screening for RHDV/RHDV2 antibodies at capture. Rabbits were monitored regularly until their death or humane killing at 7 days post infection. Liver and eyeball samples were collected for lagovirus testing and aging rabbits, respectively. At capture, rabbits showed high seroprevalence to RHDV2 but not to RHDV. In RHDV/RHDV2 seronegative rabbits at capture, infection rates were highest in those inoculated with RHDV2 (81.8%, 18 out of 22), followed by K5 (53.8%, seven out of 13) and CZECH (40.0%, two out of five), but these differences were not statistically significant. In rabbits with previous exposure to RHDV2 at capture, infection rates were highest when inoculated with K5 (59.6%, 31 out of 52) followed by CZECH (46.0%, 23 out of 50), with infection rates higher in younger rabbits for both viruses. In RHDV/RHDV2 seronegative rabbits at capture, case fatality rates were highest for those inoculated with K5 (71.4%), followed by RHDV2 (50.0%) and CZECH (50.0%). In rabbits with previous exposure to RHDV2 at capture, case fatality rates were highest in rabbits inoculated with K5 (12.9%) followed by CZECH (8.7%), with no case fatalities following RHDV2 inoculation. Case fatality rates did not differ significantly between inoculums in either serostatus group at capture. Based on multivariable modelling, time to death post RHDV inoculation increased in rabbits with recent RHDV2 exposure compared with seronegative rabbits and with age. The results suggest that RHDV2 may cause higher mortalities than other variants in seronegative rabbit populations but that K5 may be more effective in reducing rabbit populations in an RHDV2-dominant landscape.

Investigation of risk factors associated with sub-optimal holding survival in southern rock lobster (Jasus edwardsii) in Australia.

Southern rock lobster (SRL1, Jasus edwardsii) are caught from the wild waters of southern Australia and form an important commodity economically for the fisheries industry in Australia. Between landing and export, SRL are held in specialised tanks within holding facilities for varying time periods before being exported to China. During the 2015-16 fishing season a lower stock survival rate was reported by some holding facilities when compared to previous fishing seasons. An investigation was undertaken to identify possible causes and favouring factors using a retrospective, single cohort, observational study. A custom questionnaire was built and trialled to collect qualitative and quantitative information on facilities infrastructure and capacity (10 questions), water systems (16 questions), SRL stock and health management (12 questions). Onsite visits and interviews of consenting holding facilities, with active holding operations, were conducted. Facilities were categorised into different capacity and management profiles based on a multivariate factor analysis. The association between facility profiles and perceived sub-optimal survival was then explored using simple logistic regression models. Out of the 83 license holders on record, 63 were in operation at the time of survey and 52 (83%) consented to participate. Perceived sub-optimal survival was reported in 22 (42%) facilities. The capacity, bio-filtration and water management practices across the surveyed facilities was highly variable but did not appear to be associated with survival. However, 'Intensive holding' facilities compared to the 'Extensive holding' facilities were significantly associated with an increased risk of sub-optimal survival (OR = 7.0, 95% CI: 2.1-26.13, P = 0.002). 'Intensive holding' facilities were more likely to hold higher annual tonnage sourced from distant, diverse and higher number of sources, to multiple handle and stock SRL in crates (as opposed to free swimming in tanks), and hold them for longer time periods. Holding practices are highly diverse across the SRL industry with little evidence of impact on survival, however, intensive and large scale holding practices appeared to be at higher risk of sub-optimal survival. A longitudinal and finer scale study is warranted to identify which one(s) of the stock management practices directly impact SRL survival during holding.

Diagnostic Challenges in Canine Parvovirus 2c in Vaccine Failure Cases.

In this study, three different diagnostic tests for parvovirus were compared with vaccination status and parvovirus genotype in suspected canine parvovirus cases. Faecal samples from vaccinated (N17) and unvaccinated or unknown vaccination status (N41) dogs that had clinical signs of parvovirus infection were tested using three different assays of antigen tests, conventional and quantitative PCR tests. The genotype of each sample was determined by sequencing. In addition to the suspected parvovirus samples, 21 faecal samples from apparently healthy dogs were tested in three diagnostic tests to evaluate the sensitivity and specificity of the tests. The antigen test was positive in 41.2% of vaccinated dogs and 73.2% of unvaccinated diseased dogs. Conventional PCR and qPCR were positive for canine parvovirus (CPV) in 82.4% of vaccinated dogs and 92.7% of unvaccinated dogs. CPV type-2c (CPV-2c) was detected in 82.75% of dogs (12 vaccinated and 36 unvaccinated dogs), CPV-2b was detected in 5.17% dogs (one vaccinated and two unvaccinated) and CPV-2a in 1.72% vaccinated dog. Mean Ct values in qPCR for vaccinated dogs were higher than the unvaccinated dogs (p = 0.049), suggesting that vaccinated dogs shed less virus, even in clinical forms of CPV. CPV-2c was the dominant subtype infecting dogs in both vaccinated and unvaccinated cases. Faecal antigen testing failed to identify a substantial proportion of CPV-2c infected dogs, likely due to low sensitivity. The faecal samples from apparently healthy dogs (n = 21) showed negative results in all three tests. Negative CPV faecal antigen results should be viewed with caution until they are confirmed by molecular methods.

Investigation of Toxoplasma gondii and association with early pregnancy and abortion rates in New Zealand farmed red deer (Cervus elaphus).

This study tested for association between Toxoplasma gondii and pregnancy and abortion to investigate sub-optimal reproduction in farmed red deer (Cervus elaphus). Sera from a sub-sample (n = 2304) of pregnant and non-pregnant hinds in early gestation at first pregnancy scan (scan 1) and approximately at the end of second trimester at second pregnancy scan (scan 2) were tested for T. gondii antibodies using a validated ELISA. Foetuses and/or uteri from pregnant, non-pregnant, and aborting hinds at scan 1, scan 2, or weaning were tested for T. gondii DNA by nested PCR. At scan 1, 31.1% of 861 rising two-year-old (R2) and 28.3% of 357 mixed-aged (MA, ≥ 2 years) hinds were sero-positive. There was no association between scan 1 serology and non-pregnancy at animal (R2, p = 0.05 and MA, p = 0.43) or herd level (R2, p = 0.37). Toxoplasma gondii DNA was detected in 3/18 placenta and 4/18 foetal brains from aborting R2 hinds and 15/157 R2 and 3/21 MA uteri from non-pregnant hinds at scan 1. At scan 2, sero-prevalence was higher (odds ratio = 1.6, 95% CI = 1.04-2.48) in aborted (34.3% of 268) than in non-aborted (23.5% of 446) R2 hinds (p = 0.03) and 7.9% of abortions between scans were attributable to T. gondii exposure. Within-herd sero-prevalence at scan 2 was positively associated with daily abortion rate in R2 herds with aborted hinds (p < 0.001) but not in MA herds (p = 0.07). Toxoplasma gondii DNA was detected in 27/169 uteri, 2/20 cotyledons, and 1/5 foetal brains from aborted hinds at scan 2 and in uteri from 5/33 hinds not rearing a calf to weaning. Toxoplasma gondii RFLP genotyping of five loci revealed a unique type I/III genotype pattern, TgRDNZ1, in a foetal brain sample, not been previously reported in deer. These findings provide serological and molecular evidence that T. gondii infection is associated with abortion in red deer, possibly in all three trimesters.

Pregnancy and mid-term abortion rates in farmed red deer in New Zealand.

This paper describes pregnancy and mid-term abortion rate data from an investigation of sub-optimal reproductive performance in New Zealand farmed red deer. For 2 years, 87 yearling (YL) and 71 mixed-age adult (MA) herds from 85 farms were observed with 15 YL and seven MA herds observed both years. Hinds were pregnancy diagnosed using ultrasonography in the late autumn-early winter (PD1) and again late winter-early spring (PD2) and mid-term daily abortion rates (DAR) were calculated. Overall, 85.8% of 22,130YL (range, 7.0%-100% between herds) and 93.3% of 36,223 MA hinds (range, 39.8%-100% between herds) were pregnant at PD1. The mean interval between ultrasonic assessments was 90 and 87 days in YL and MA herds, respectively. Mid-term abortions occurred in 305 (2.8%) hinds from 60 (73%) YL herds and 92 (1.2%) hinds from 36 (61%) MA herds. The mean mid-term DAR, was greater (P = 0.009) in YL (mean 0.043%, range 0.005%-0.213%, 95% CI = 0.034-0.053) than MA herds (mean 0.025%, range 0.007%-0.101%, 95% CI = 0.018-0.032). In herds with hinds that aborted, the mean DAR was greater in small than large YL herds (0.055% compared with 0.033%, P = 0.023), but not MA herds. At PD1, 46 YL and 12 MA hinds had ultrasonographic evidence of abortions from 22 herds. This, combined with the 1.2% to 7.1% foetal loss in three herds pregnancy diagnosed earlier than the usual PD1 date as a pilot to test for earlier abortion, supports that abortion can occur prior to normal pregnancy assessment dates, contributing to sub-optimal pregnancy rates. Abortion rates were not consistent within herd between years for either YL or MA herds. Thus, early and mid-term abortion is prevalent in New Zealand farmed deer constituting a significant production cost, warranting further investigation into causation.

Evaluation of Western blot, ELISA and latex agglutination tests to detect Toxoplasma gondii serum antibodies in farmed red deer.

Abortion due to Toxoplasma gondii has been suspected in New Zealand farmed red deer. However, knowledge around the epidemiology and prevalence of T. gondii in farmed red deer is limited. The aim of this study was to firstly, assess the sensitivity and specificity of two commercially available assays, ELISA and latex agglutination test (LAT), for use in deer and secondly, to estimate the sero-prevalence of T. gondii in red deer. A total of 252 sera from rising 2-year-old and adult hinds from 17 New Zealand red deer herds at early and late pregnancy scanning and from known aborted and/or non-aborted hinds were tested for the presence of T. gondii antibodies. Each assays' sensitivity and specificity was evaluated by both the Western Blot (WB) as a gold standard method and Bayesian latent class (BLC) analysis in the absence of a gold standard. The sensitivity and specificity for WB were 95.8% (95% credible interval: 89.5-99.2%) and 95.1% (95% credible interval: 90.6-98.1%), respectively. For the LAT at the manufacturer's recommended ≥1:32 cut-off titre, the sensitivity (88.7%, 95% credible interval: 80.8-94.7%) and specificity (74.3%, 95% credible interval: 67.5-80.5%) were lower and higher than the sensitivity (76.2%, 95% credible interval: 66.7-84.5%) and specificity (89.7%, 95% credible interval: 84.5-93.9%) at a ≥1:64 cut-off, using (BLC) analysis. Sensitivity and specificity of the LAT at cut-off titre of 1:32 were estimated to be 84.4% (95% CI: 74.9-90.9%) and 73.5% (95% CI: 65.8-79.9%) against WB. The LAT had better agreement with WB at cut-off titre of ≥1:64 than ≥1:32 (Kappa=0.63 vs 0.54). At optimised cut-off S/P of 15.5%, the sensitivity (98.8%, 95% credible interval 96.1-99.8%) and specificity (92.8%, 95% credible interval 88.9-95.7%) of the ELISA were higher and lower, respectively, than the sensitivity (85.1%, 95% credible interval 76.2-91.9%) and specificity (98.5%, 95% credible interval 96.9-99.4%) at manufacturer's cut-off S/P of 30%, from BLC analysis. The sensitivity and specificity of ELISA at S/P cut-off of 15.5% was 91.1% (95% CI: 83.2-96.1%) and 90.7% (95% CI: 85.2-94.7%), respectively, when assessed against WB. The sero-prevalence from ELISA and LAT, at cut-off of S/P 15.5% and ≥1:64, respectively, was not significantly different to that from WB (McNemar's Chi-square p=0.21 for ELISA and p=0.28 for LAT).

Synthesis and characterization of carboxymethyl chitosan hydrogel: application as pH-sensitive delivery for nateglinide.

In current research, chitosan was reacted with mono-chloroacetic acid under alkaline condition to prepare carboxymethyl chitosan (CMCTs). The degree of substitution (Ds) on prepared CMCTs was found to be 0.68. CMCTs was used as a potential carrier for pH specific delivery of nateglinide after crosslinked using glutaraldehyde in presence of nateglinide. The average molecular weight and degree of deacetylation (DD) of chitosan were found to be 3.5x104 Da and 84.6% respectively. High yield (82%) and loading of drug (75%) were found in the developed hydrogel formulations. pH responsive swelling behavior of prepared hydrogels was checked using different pH values (1.2, 6.8 and 7.4). The study indicated very less swelling at pH 1.2 (for first 2 h) and quick swelling at pH 6.8 (for next 3 h) followed by linear swelling at pH 7.4 (for next 7 h) with slight increase. In vitro release profile of hydrogels showed biphasic release pattern dependent on swelling behavior. The release pattern was found to be non-fickian diffusion kinetics at higher pH. FTIR, 1H-NMR, DSC and p-XRD studies were carried out to confirm the formation of CMCTs, drug entrapment and its possible interaction in formulations. These studies revealed that no chemical change was found in nateglinide during preparation of hydrogel formulations. Scanning Electron Microscopy (SEM) was used to study the surface morphology of prepared hydrogels before and after dissolution which revealed pores formation after dissolution.

Design of optimized diffusion-controlled transdermal drug delivery systems.

BACKGROUND: We describe a systematic approach to designing multilayer transdermal patches based on therapeutically relevant specifications of the drug. METHOD: Random search optimization techniques are used to optimize maximum drug release from the patch subject to the therapeutic specifications. Barrier layer thickness and relative concentrations of the drug in the drug-containing layers are used as key design parameters. RESULTS: A patch made of two drug-containing layers of equal thicknesses and relative drug concentrations of 20% and 80%, and a barrier layer with thickness of 14% compared to the total thickness of drug-containing layers was found to be the most optimum design. CONCLUSION: The proposed design is almost universally applicable and satisfies therapeutically relevant specifications while maximizing drug utilization.

The safety and feasibility of large volume paracentesis performed by an experienced nurse practitioner.

Due to time constraints, fewer physicians are performing large volume paracentesis (LVP) resulting in a longer wait time and more emergency department (ED) and hospital admissions. At our institution, after initial supervision, a certified nurse practitioner (NP) has independently performed LVP in a dedicated cirrhosis clinic. The purpose of our study was to evaluate the feasibility and safety of LVP performed by a NP. A retrospective review of patients undergoing LVP between January 2003 and May 2007 was performed. Baseline patient information and the practitioner performing LVP (physician or NP) were recorded. Complications including post paracentesis hypotension, bleeding, local leakage of ascitic fluid, infection, perforation, and death were compared between the two groups. A total of 245 procedures in 41 patients were performed by a single NP, and 244 in 43 patients by physicians. Baseline characteristics of patients undergoing LVP were similar in two groups. Alcohol was the most common etiology of cirrhosis (46% in NP and 51% in physician group) followed by a combination of alcohol plus HCV (37% in NP and 28% in physician group). There was similar distribution of Childs class B and C patients in the two groups, as well as average MELD score. Total volume of ascites removed, number of needle attempts, and complications including post paracentesis hypotension, local leakage of ascitic fluid, bleeding, infection, and death were not statistically different between the two groups. Our study shows no difference between physician and NP performance of LVP and complication rates. LVP performed by a NP is feasible and has acceptable rate of complications.