Highly Pathogenic Avian Influenza Virus A/H5N1 Infection in Vaccinated Meat Duck Flocks in the Mekong Delta of Vietnam.

We investigated episodes of suspected highly pathogenic avian influenza (HPAI)-like illness among 12 meat duck flocks in two districts in Tien Giang province (Mekong Delta, Vietnam) in November 2013. In total, duck samples from 8 of 12 farms tested positive for HPAI virus subtype A/haemagglutinin 5 and neuraminidase 1 (H5N1) by real-time RT-PCR. Sequencing results confirmed clade of 2.3.2.1.c as the cause of the outbreaks. Most (7/8) laboratory-confirmed positive flocks had been vaccinated with inactivated HPAI H5N1 clade 2.3.4 vaccines <6 days prior to onset of clinical signs. A review of vaccination data in relation to estimated production in the area suggested that vaccination efforts were biased towards larger flocks and that vaccination coverage was low [21.2% ducks vaccinated with two shots (range by district 7.4-34.9%)]. The low-coverage data, the experimental evidence of lack of cross-protection conferred by the currently used vaccines based on clade 2.3.4 together with the short lifespan of meat duck flocks (60-70 days), suggest that vaccination is not likely to be effective as a tool for control of H5N1 infection in meat duck flocks in the area.

Effective models for medical and health response coordination: summary and action plan.

INTRODUCTION: To effectively respond to this relatively new, complex mandate, it is essential to find effective models of coordination to ensure that medical and health services can meet the standards now expected in a disaster situation. This theme explored various models, noting both the strengths that can be built on and the weaknesses that still need to be overcome. METHODS: Details of the methods used are provided in the preceding paper. The chairs moderated all presentations and produced a summary that was presented to an assembly of all of the delegates. Since the findings from the Theme 1 and Theme 4 groups were similar, the chairs of both groups presided over one workshop that resulted in the generation of a set of Action Plans that then were reported to the collective group of all delegates. RESULTS: The main points developed during the presentations and discussion included: (1) preplanning (predisaster goals), (2) information collection (assessment), (3) communication (materials and methods); and (4) response centres and personnel. There exists a need for institutionalization of processes for learning from experiences obtained from disasters. DISCUSSION: Action plans presented include: (1) creation of an information and data clearinghouse on disaster management, (2) identification of incentives and disincentives for readiness and develop strategies and interventions, and (3) action on lessons learned from evidence-based research and practical experience. CONCLUSIONS: There is an urgent need to proactively establish coordination and management procedures in advance of any crisis. A number of important insights for improvement in coordination and management during disasters emerged.

Prognostic implications of hyperkalemia in toad toxin intoxication.

The toad possesses several toxic substances. Toad toxin poisoning manifests itself primarily with digitalis-like, cardioactive effects which results in bradycardia, varying degrees of atrio-ventricular block, ventricular tachycardia, ventricular fibrillation and sudden death. We report a cluster poisoning in a family who became intoxicated after ingestion of cooked toad soup for a skin problem. The youngest one (15 months old) died of refractory bradydyarrhythmias soon after arriving at our hospital. A second child (20 months old), who survived, arrived in shock with hyperkalemia (potassium 7.3 mEq/ L) and varying degrees of atrio-ventricular block. She was successfully treated with atropine, lidocaine, and cardioversion, and had a transvenous temporary pacemaker implanted for 1 day. The third boy (16 years old) had hyperkalemia (potassium 6.3 mEq/L) and bradycardia. The remaining three adults had only mild symptoms of nausea, vomiting, watery diarrhea and a sensation of numbness over their oral mucosa. We found that the level of serum potassium had prognostic implications in toad intoxication. Determination of serum potassium level is readily available in almost every hospital and is therefore more convenient to measure than serum digoxin level. We conclude that if hyperkalemia develops, the treatment of toad intoxication must be more aggressive to prevent mortality.

Decomposition of arteether in simulated stomach acid yielding compounds retaining antimalarial activity.

In simulated stomach acid (aqueous 0.01 M HCl, 37 degrees C) beta-arteether decomposed (half-life, 441 +/- 17 min) to dihydroartemisinin, which subsequently rearranged to a new compound (1) having an endoperoxide group and an aldehyde group. The in vitro antimalarial activity of dihydroartemisinin is similar to that of beta-arteether, whereas compound 1 had approximately 1/10th the activity of beta-arteether. Compound 1 was prepared in sufficient quantities to afford samples for biological evaluation and a complete chemical characterization with 1H- and 13C-NMR and mass spectrometry. While beta-arteether would be somewhat unstable in the stomach, if the drug were administered on an empty stomach (emptying time, approximately 30 min) as a suspension or tablet, sufficient quantities of intact arteether may reach the small intestines, where it would be stable and readily absorbed. Its decomposition products, dihydroartemisinin and 1, may also contribute to the antimalarial activity of the administered drug following oral administration.

Identification of the in vivo metabolites of the antimalarial arteether by thermospray high-performance liquid chromatography/mass spectrometry.

The thermospray mass spectra of arteether and 16 of its potential metabolites all showed strong [M + NH4]+ ions and with only a few exceptions these compounds also showed spectral peaks corresponding to [M + NH4 - HOR]+ and [M + H - HOR]+, where OR represents the alkoxy or hydroxy group at the 12-position. A method for quantifying the metabolites was developed in which the plasma was spiked with an internal standard (the propyl ether analog of arteether), extracted using a C-18 solid-phase cartridge, then subjected to thermospray high-performance liquid chromatographic/mass spectrometric analysis using selected ion monitoring and a C-18 reversed-phase analytical column. Following the intravenous administration of arteether (11.6 mg kg-1), the plasma was found to contain 12 metabolites of arteether in the 10-1000 ng ml-1 range 15 min post-injection, and within 60 min two of these metabolites attained higher concentrations than that of the parent compound, while several other of the metabolites attained concentrations similar to the parent compound. The pseudo-first-order half-life of arteether was found to be 10.0 +/- 0.6 min, while the apparent half-lives of most of the metabolites were in the 15-30 min range. Nine of these metabolites were identified by comparison to authentic reference standards and the structures of three remaining metabolites were tentatively assigned from their spectral and chromatographic properties. The metabolic pathways leading to these 12 metabolites was a rather complex, multiple-step process, but most of the metabolites arose from an enzymatic oxidation at one of three sites; 3 alpha, 9 alpha, or the CH2 of the side-chain. Conversion of the endoperoxide group to an cyclic ether was not a major pathway. The in vitro antimalarial activity of reference standards of several of the metabolites was determined and all of those tested were found to be active in the low nanogram per milliliter range.

Structure elucidation and thermospray high-performance liquid chromatography/mass spectroscopy (HPLC/MS) of the microbial and mammalian metabolites of the antimalarial arteether.

Microbial metabolism studies of the antimalarial drug arteether (1) have shown that arteether is metabolized to six new metabolites in addition to those previously reported (3). Large-scale fermentations with Cunninghamella elegans (ATCC 9245) and Streptomyces lavendulae (L-105) have resulted in the characterization of these metabolites primarily by two-dimensional nuclear magnetic resonance (2D-NMR) methods as 9 beta-hydroxyarteether (2), a ring rearrangement metabolite (3), 3 alpha-hydroxy-11-epi-deoxydihydroartemisinin (4), 9 alpha-hydroxyarteether (5), 2 alpha-hydroxyarteether (6), and 14-hydroxyarteether (7). Thermospray mass spectroscopy/high-performance liquid chromatographic analyses have shown that four of these metabolites (2, 5, 6, 7) are also present in rat liver microsome preparations.