Duck egg drop syndrome virus: an emerging Tembusu-related flavivirus in China

Abstract

Duck egg drop syndrome virus (DEDSV) is a newly emerging pathogenic flavivirus isolated from ducks in China. DEDSV infection mainly results in severe egg drop syndrome in domestic poultry, which leads to huge economic losses. Thus, the discovery of ways and means to combat DEDSV is urgent. Since 2010, a remarkable amount of progress concerning DEDSV research has been achieved. Here, we review current knowledge on the epidemiology, symptomatology, and pathology of DEDSV. A detailed dissection of the viral genome and polyprotein sequences, comparative analysis of viral antigenicity and the corresponding potential immunity against the virus are also summarized. Current findings indicate that DEDSV should be a distinct species from Tembusu virus. Moreover, the adaption of DEDSV in wildlife and its high homology to pathogenic flaviviruses (e.g., West Nile virus, Japanese encephalitis virus, and dengue virus), illustrate its reemergence and potential to become a zoonotic pathogen that should not be overlooked. Detailed insight into the antigenicity and corresponding immunity against the virus is of clear significance for the development of vaccines and antiviral drugs specific for DEDSV.

Pathogenicity and genetic characterization of a duck Tembusu virus associated with egg-dropping in Muscovy ducks

“…High RNA copies were detected in the Spleens and livers of the infected ducks on day 3 post-inoculation (Fig 2B), the kidneys, hearts and lungs of the infected ducks were also viral RNA positive and no RNA was detected in the brains of the infected ducks ( Fig 2B). The lesions of the affected laying ducks were similar with those in other laying ducks (Cao et al, 2011;Liu et al, 2013;Su et al, 2011;Yan et al, 2011). These results provided evidence that DTMUV could cause severe egg production drop for laying Muscovy drop, which highlighted that effective measures must be taken to prevent against this virus in Muscovy duck farms.…”

Advanced uracil DNA glycosylase-supplemented real-time reverse transcription loop-mediated isothermal amplification (UDG-rRT-LAMP) method for universal and specific detection of Tembusu virus

“…Since 2010, a highly contagious disease has spread throughout most breeder, layer, and meat-type duck farms in China, causing significant economic losses in the Chinese duck industry2. In addition to ducks, TMUVs are commonly detected in other domestic and wild avian species including geese12, layer chicken13, pigeons14, and house sparrows3. TMUV-infected birds exhibit various disease conditions as documented in the literature; in particular, high fever, loss of appetite, severe reduction in egg production, and/or severe neurologic disorders were commonly observed in TMUV-affected flocks1.…”

Liposomes containing recombinant E protein vaccine against duck Tembusu virus in ducks

“…hemorrhage, ovaritis, and regression were also consistently found [33]. DTMUV mainly infect the reproductive system and can be isolated from duck embryos, which provided evidence of possible vertical transmission of TMUV from breeding ducks to ducklings [34] and the host of DTMUV can vary [35].…”

“…On clinical symptoms, it usually occur with serious anorexia, severe neurologic symptoms, and a heavy drop in egg production [33]; as well as on necropsy, in the infected ducks, severe ovarian Detections of viremia and virus shedding of ducks post challenge with DTMUV of group 0 (control), group 2 (L + E 1st, 7th day twice) and group 5 (F + E 1st, 7th day twice). Viremia was tested independently for each duck from the 1st to 5th day post-challenge (A).…”

“…Since April 2010, a newly emerged infectious disease in ducks which characterized by acute anorexia, retarded growth, neurological dysfunction and severe egg production drop has spread rapidly to all of the south-east provinces of China, causing serious economic losses in the Chinese duck industry [1][2][3]. The causative agent has been identified as duck Tembusu virus (DTMUV) belonging to the Ntaya virus (NTAV) group within the family Flaviviridae, genus Flavivirus, and the morbidity rate of which can reach up to 90%, as well as the mortality rates vary from 5% to 30% [4].…”