DAO

Diseases of Aquatic Organisms

DAO is a hybrid research journal on all aspects of disease phenomena in aquatic organisms.

Online: ISSN 1616-1580

Print: ISSN 0177-5103

DOI: https://doi.org/10.3354/dao

Impact Factor1.2 (JCR 2025 release)

Article Acceptance Rate47.2% (2024)

Average Time in Review183 days (2024)

Total Annual Downloads629.123 (2025)

Volume contents
Dis Aquat Org 61:227-233 (2004)

Experimental infection of Pacific white shrimp Litopenaeus vannamei with Necrotizing Hepto-pancreatitis (NHP) bacterium by per os exposure

ABSTRACT: Necrotizing Hepatopancreatitis Bacterium (NHPB), which causes Necrotizing Hepatopancreatitis, was successfully transmitted in individually isolated Kona stock Litopenaeus vannamei through per os exposure. Animals (140) were individually exposed orally to a 0.05 g piece of an NHPB-infected hepatopancreas and 120 control animals were each exposed to a 0.05 g piece of NHPB-negative hepatopancreas. Shrimp were maintained in Sterilite® containers with approximately 4 l of artificial seawater at 30‰ salinity and 30°C for 60 d. Mortality of infected shrimp was observed from Day 16 to Day 51 post-exposure. Infected animals sustained reduced feeding activity and displayed empty guts. Some infected animals developed a pale hepatopancreas noticeable through the carapace. Survival probabilities fit a Weibull distribution and parametric survival analysis revealed lowered survival due to NHPB infection. Median survival time of NHPB-infected animals was 34.5 d. After correcting for background daily mortality in the controls, mean acute daily mortality of NHPB was estimated at 0.09, a value much lower than that estimated for other diseases in Kona stock L. vannamei such as White Spot Syndrome Virus (0.40) and Taura Syndrome Virus (0.30). A chronic, or carrier, state was not demonstrated in NHPB epizootics because all NHPB-positive animals experienced mortality and no animals surviving to 60 d post-exposure were diagnosed NHPB-positive through PCR or histology.

KEYWORDS

Amanda G. Vincent (Co-author)

Verlee M. Breland (Co-author)

J. M. Lotz (Corresponding Author)
jeff.lotz@usm.edu