World Aquaculture Singapore 2022

November 29 - December 2, 2022

Singapore

CURRENT STATUS OF INFECTION WITH INFECTIOUS HYPODERMAL AND HEMATOPOIETIC NECROSIS VIRUS (IHHNV) IN THE PERUVIAN AND ECUADORIAN SHRIMP INDUSTRY

Luis Fernando Aranguren Caro1*, Muriel Gomez-Sanchez2, Yahira Piedrahita3, Hung N. Mai1, Roberto Cruz-Flores1,4, Rod Russel R. Alenton1, Arun K. Dhar1

 

 

1 Aquaculture Pathology Laboratory, School of Animal and Comparative Biomedical Sciences, The University of Arizona, 1117 E Lowell St. Tucson, Arizona, USA 85721

2 Subdireccion de Sanidad, Dirección de Sanidad e inocuidad, National Fisheries Health Agency in Peru (SANIPES), Calle Amador Merino Reyna N° 263, San Isidro, Lima, Perú

3 Camara Nacional de Acuacultura, CNA, Avenida Francisco de Orellana y Miguel H Alcivar, Guayaquil, Ecuador

4 Centro de Investigación Científica y Educación Superior de Ensenada (CICESE), Carretera Ensenada-Tijuana No. 3918, Zona Playitas, 22860 Ensenada, Baja CA, México

 

* Corresponding author:
E-mail: lfarangu@email.arizona.edu (LFAC)

 



Infection with infectious hypodermal and hematopoietic necrosis virus (IHHNV) is a crustacean disease that caused large-scale mortality in Penaeus stylirostris, deformity and growth retardation in Penaeus vannamei and Penaeus monodon. We surveyed the presence of IHHNV in three major shrimp-producing regions in Ecuador, namely Guayas, El Oro, and Esmeralda. The data show that IHHNV is endemic (3.3–100% prevalence) to shrimp farms in these regions. The whole genome sequences of representative circulating IHHNV genotypes in Ecuador and Peru showed that these genotypes formed a separate cluster within the Type II genotypes and were divergent from other geographical isolates of IHHNV originating in Asia, Africa, Australia, and Brazil. In experimental bioassays using specific pathogen-free (SPF) P. vannamei, P. monodon, and P. stylirostris and representative IHHNV isolates from Ecuador and Peru, the virus did not cause any mortality or induce clinical signs in any of the three penaeid species. Although IHHNV-specific Cowdry type A inclusion bodies were histologically detected in experimentally challenged P. vannamei and P. monodon and confirmed by in situ hybridization, no such inclusions were observed in P. stylirostris. Moreover, P. vannamei had the highest viral load, followed by P. monodon and P. stylirostris. Based on IHHNV surveillance data, we conclude that the currently farmed P. vannamei lines in Ecuador are tolerant to circulating IHHNV genotypes. The genome sequence and experimental bioassay data showed that, although the currently circulating genotypes are infectious, they do not induce clinical lesions in the three commercially important penaeid species. These findings suggest a potentially evolving virus-host relationship where circulating genotypes of IHHNV co-exist in equilibrium with P. vannamei raised in Peru and Ecuador.