Zoonotic origin and transmission of Middle East respiratory syndrome coronavirus in the UAE

Since the emergence of Middle East respiratory syndrome coronavirus (MERS‐CoV) in 2012, there have been a number of clusters of human‐to‐human transmission. These cases of human‐to‐human transmission involve close contact and have occurred primarily in healthcare settings, and they are suspected to result from repeated zoonotic introductions. In this study, we sequenced whole MERS‐CoV genomes directly from respiratory samples collected from 23 confirmed MERS cases in the United Arab Emirates (UAE). These samples included cases from three nosocomial and three household clusters. The sequences were analysed for changes and relatedness with regard to the collected epidemiological data and other available MERS‐CoV genomic data. Sequence analysis supports the epidemiological data within the clusters, and further, suggests that these clusters emerged independently. To understand how and when these clusters emerged, respiratory samples were taken from dromedary camels, a known host of MERS‐CoV, in the same geographic regions as the human clusters. Middle East respiratory syndrome coronavirus genomes from six virus‐positive animals were sequenced, and these genomes were nearly identical to those found in human patients from corresponding regions. These data demonstrate a genetic link for each of these clusters to a camel and support the hypothesis that human MERS‐CoV diversity results from multiple zoonotic introductions.     

Hepatitis E in southern Vietnam: Seroepidemiology in humans and molecular epidemiology in pigs

Viral pathogens account for a significant proportion of the burden of emerging infectious diseases in humans. The Wellcome Trust‐Vietnamese Initiative on Zoonotic Infections (WT‐VIZIONS) is aiming to understand the circulation of viral zoonotic pathogens in animals that pose a potential risk to human health. Evidence suggests that human exposure and infections with hepatitis E virus (HEV) genotypes (GT) 3 and 4 results from zoonotic transmission. Hypothesising that HEV GT3 and GT4 are circulating in the Vietnamese pig population and can be transmitted to humans, we aimed to estimate the seroprevalence of HEV exposure in a population of farmers and the general population. We additionally performed sequence analysis of HEV in pig populations in the same region to address knowledge gaps regarding HEV circulation and to evaluate if pigs were a potential source of HEV exposure. We found a high prevalence of HEV GT3 viral RNA in pigs (19.1% in faecal samples and 8.2% in rectal swabs) and a high HEV seroprevalence in pig farmers (16.0%) and a hospital‐attending population (31.7%) in southern Vietnam. The hospital population was recruited as a general‐population proxy even though this particular population subgroup may introduce bias. The detection of HEV RNA in pigs indicates that HEV may be a zoonotic disease risk in this location, although a larger sample size is required to infer an association between HEV positivity in pigs and seroprevalence in humans.     

Characteristics of two duck farming systems in the Mekong Delta of Viet Nam: stationary flocks and moving flocks, and their potential relevance to the spread of highly pathogenic avian influenza

Ducks are considered to play a major role in the spread of highly pathogenic avian influenza (HPAI) H5N1 in Viet Nam, but detailed information on their management is limited. We distinguished two different systems (1) stationary duck flocks that are not commonly driven to rice fields beyond village boundaries and that are confined overnight on farms and (2) moving duck flocks that are intentionally driven to rice fields beyond village boundaries, that are not returning to home farms for extended periods and that are housed overnight in temporary enclosures in rice paddies. A total of 115 stationary and 22 moving flock farmers were interviewed in 2007 in the Mekong Delta of Viet Nam. Moving duck flocks are larger than stationary flocks, which is indicative of their more commercial production. Moving flock farmers apparently are more aware of HPAI risks than stationary flock farmers, as their flocks are more likely fully vaccinated and have less contact with chickens during scavenging. On the other hand, the spread of HPAI virus between birds might be promoted by moving duck flocks as they repeatedly use transport vehicles and numerous rice paddies for scavenging and are often visited by hatchery owners in the field for purchasing duck eggs. In addition, long distances travelled by moving duck flocks might also result in widespread dissemination of HPAI virus. Further studies are necessary to describe HPAI prevalence and travel patterns of moving duck flocks and to explore the moving duck flock network in detail.     

Sperm Motilities in Waigieu Seaperch,Psammoperca waigiensis: Effects of Various Dilutions,pH, Temperature,Osmolality, and Cations

The objectives of this study were to evaluate the effects of varying dilutions, pH, temperature, osmolality, and cations on sperm motility parameters in waigieu seaperch, Psammoperca waigiensis. The maximum velocity of average in path (VAP), percentage of motile cells (MOT), and duration of sperm motility (DSM) were observed when semen was diluted in artificial seawater (ASW) at a ratio of 1:100 (144.9 ± 0.6 µm/sec, 95.6 ± 0.4%, and 230.3 ± 2.3 sec, respectively), at 30 C (142.0 ± 0.6 µm/sec, 93.6 ± 0.4%, and 238.3 ± 0.9 sec, respectively), and pH 8 (144.8 ± 0.6 µm/sec, 93.3 ± 0.4%, and 234.0 ± 1.5 sec, respectively). Maximum VAP, MOT, and DSM were obtained in each solution containing 0.6 M NaCl (143.8 ± 1.0 µm/sec, 91.3 ± 2.0%, and 230.6 ± 4.2 sec, respectively), 0.6 M KCl (135.1 ± 3.1 µm/sec, 91.1 ± 3.1%, and 230.3 ± 3.7sec, respectively), 0.2M CaCl₂ (105.3 ± 4.7μm/sec, 47.9 ± 2.7%, and 120.7 ± 1.3 sec, respectively), 0.2 M MgCl₂ (107.3 ± 3.0 m/s, 42.1 ± 3.3%, and 120.3 ± 4.8 sec, respectively), and osmolality of 400 mOsm/kg (145.1 ± 2.5 µm/sec, 93.0 ± 2.1%, and 346.5 ± 4.4s, respectively). We used these mediums as artificial insemination media for fertilizing matured eggs. The results showed that the fertilization and hatching rates in 0.6 M NaCl (75.3 ± 0.6% and 57.0 ± 2.4%, respectively), ASW (70.8 ± 1.2% and 51.2 ± 1.8%, respectively), or 400 mOsm/kg (72.9 ± 1.8% and 55.3 ± 1.6%, respectively) were higher than that in seawater (63.9 ± 1.2% and 39.2 ± 3.9%, respectively). In conclusion, using 0.6 M NaCl, ASW, or 400 mOsm/kg as an artificial insemination medium is effective for fertilizing of waigieu seaperch.     

The Effects of Different Feed Enrichments on Survivorship and Growth of Early Juvenile Longsnout Seahorse,Hippocampus reidi

Culturing the longsnout seahorse, Hippocampus reidi, remains challenging because unlike most cultured seahorse species, Artemia is not an optimal first feed. Ideally, more nutritious live feeds such as wild plankton or copepods should be used, but are not always readily available. Therefore, facilities commonly utilize enriched rotifers. Numerous feed enrichment products exist, including Dan's Feed Artemia Enrichment^®, (Dan's Feed) which is a blend of commercially available enrichment products. The aim of this study was to assess the survivorship, growth, and condition factor (CF) of 0–28 DPR (days post release) H. reidi fed with rotifers and Artemia enriched with Dan's Feed. This enrichment was evaluated against (1) rotifers and Artemia enriched with live alga (Isochrysis galbana), and (2) wild plankton and Artemia enriched with Dan's Feed. At 28 DPR, in terms of survivorship and growth, seahorses fed with rotifers and Artemia enriched with Dan's Feed had a lower CF and outperformed those fed rotifers and Artemia enriched with I. galbana. Seahorses fed with rotifers and Artemia enriched with Dan's Feed performed on par with those fed with wild plankton and Artemia with no significant difference in CF. These findings demonstrated that the culture of H. reidi may be feasible with rotifers and Artemia enriched with Dan's Feed .     

Pine wilt disease: detection of the pinewood nematode (Bursaphelenchus xylophilus) as a tool for a pine breeding programme

The pinewood nematode (PWN), Bursaphelenchus xylophilus, is a serious quarantine pest first detected in Portugal and Europe in 1999. It is the causal agent of pine wilt disease (PWD). A resistance breeding programme has been initiated to contribute to control the evolution of the disease. Five hundred and four adult maritime pine, Pinus pinaster, trees were phenotypically selected as candidate trees for this programme from an area affected by PWD. To identify tolerance to the nematode, the selected trees were monitored monthly. Over the course of 1 year, 57 candidate trees died and were tested for the presence/absence of the PWN. As accuracy of detection is of major importance, an ITS‐PCR‐based method applied directly to wood from adult maritime pine trees was tested and compared with a standard morphological identification method. The results showed that the use of PCR to detect the pathogen provided more rapid and accurate results in comparison with the standard morphological identification. Thus, this method is suitable to be used in the survey of the breeding population for resistance/tolerance to PWD.     

Risk factors and characteristics of H5N1 Highly Pathogenic Avian Influenza (HPAI) post-vaccination outbreaks

Highly pathogenic avian influenza (HPAI) virus H5N1 is now endemic in South-East Asia but HPAI control methods differ between countries. A widespread HPAI vaccination campaign that started at the end of 2005 in Viet Nam resulted in the cessation of poultry and human cases, but in 2006/2007 severe HPAI outbreaks re-emerged. In this study we investigated the pattern of this first post-vaccination epidemic in southern Viet Nam identifying a spatio-temporal cluster of outbreak occurrence and estimating spatially smoothed incidence rates of HPAI. Spatial risk factors associated with HPAI occurrence were identified. Medium-level poultry density resulted in an increased outbreak risk (Odds ratio (OR) = 5.4, 95% confidence interval (CI): 1.6–18.9) but also climate-vegetation factors played an important role: medium-level normalised difference vegetation indices during the rainy season from May to October were associated with higher risk of HPAI outbreaks (OR = 3.7, 95% CI: 1.7–8.1), probably because temporal flooding might have provided suitable conditions for the re-emergence of HPAI by expanding the virus distribution in the environment and by enlarging areas of possible contacts between domestic waterfowl and wild birds. On the other hand, several agricultural production factors, such as sweet potatoes yield, increased buffalo density, as well as increased electricity supply were associated with decreased risk of HPAI outbreaks. This illustrates that preventive control measures for HPAI should include a promotion of low-risk agricultural management practices as well as improvement of the infrastructure in village households. Improved HPAI vaccination efforts and coverage should focus on medium poultry density areas and on the pre-monsoon time period.     

Spatial and temporal diversity of fish captured by light traps in various habitats in coastal waters in the oldest marine protected area in Vietnam and its implications for conservation

相似文献   

An application of multilevel model for the analysis of factors influencing paddy field productivity in the Northern Vietnamese Mountains

Paddy and Water Environment - In the Northern Vietnamese Mountains, paddy fields are the main source of foods and an important indicator to define wealth in ethnic communities. This paper deals...