Progression of Infection and Tumor Development in Damselfish

Abstract

The bicolor damselfish (Stegastes partitus) is a tropical marine teleost naturally affected by multiple neurofibromas and chromatophoromas on South Florida reefs. Damselfish neurofibromatosis is a transmissible disease caused by a subcellular agent. Development of tumors is associated with the appearance of a series of extrachromosomal DNAs ranging in size from 1.2 to 7 kb that appear to be the genome of a small virus-like agent which we termed the damselfish virus-like agent (DVLA). This DNA was found at high copy number in most spontaneous and experimentally induced tumors. An essentially identical pattern of DNA, but with lower copy numbers, was observed in non-tumor-bearing tissue from diseased fish. Copy numbers of DVLA DNA in tumors and nontumorous tissues increased as the disease progressed from early to late stages. In healthy fish in which DVLA DNA was detected, the quantities were much lower than those in diseased fish. Healthy fish from populations with a high prevalence of disease exhibited more infected tissues than fish from populations with low levels.

Injection of xenogeneic cells into teleost fish elicits systemic and local cellular innate immune responses

“…Although some aspects, such as tumour structure and nature, metastasis or lethal effects, have been studied, little information exists concerning the involvement of the immune system in protection against tumours (Thompson and Kostiala 1990;Vicha and Schmale 1994;McKinney and Schmale 1994a,b;Campbell et al 2001;Romano and Marozzi 2004;Schmale et al 2004). In this regard, researchers are currently attempting to establish suitable models to investigate the cytotoxic response in teleost fish.…”

Lipoid liver disease and steatitis in a captive sapphire damsel, Pomacentrus pavo

“…They are one of the most popular aquaria species in commercial and private operations and are one of the top ten most traded species which together account for approximately 36% of the marine fish traded (Wabnitz et al 2003). Besides the neurofibromatosis-like disease reported in bicolor damselfish, (Schmale and Hensley 1988, Campbell et al 2001, Schmale et al 2002 reports on other diseases affecting damselfish are lacking. Thus, it is important to document diseases as they occur in this species so that we might use this information to better manage them in captivity and perhaps better understand their needs in the wild.…”

Fighting Virus and Parasites with Fish Cytotoxic Cells

“…However, aquaculture management, intensive culture conditions and environmental contamination may increase the incidence of fish tumors. Although some aspects, such as tumour structure and nature, metastasis or lethal effects have been studied, little information exists concerning the involvement of the immune system in protection against tumours (Campbell et al, 2001;McKinney & Schmale, 1994a, 1994b, 1997Romano & Marozzi, 2004;Schmale et al, 1994Schmale et al, , 2004Thompson & Kostiala, 1990;Vicha & Schmale, 1994). Thus, most of the information regarding fish cytotoxic activity comes from the use of hapten-modified autologous cells or xenogeneic/allogeneic cell lines (Evans et al, 1984a(Evans et al, -d, 1987Fischer et al, 2006;Graves et al, 1984;Manning & Nakanishi, 1996;Nakanishi et al, 2002;Shen et al, 2002;Verlhac et al, 1990).…”

“…So far, fish immune response against tumors has been slightly evaluated. In the bicolour damselfish naturally suffering of neurofibromatosis (DNF) (caused by a retrovirus), study of the immune response has provided information with respect to CMC activity, morphology and distribution, degranulation of eosinophilic granular cells (EGCs) and lymphocyte proliferation (Vicha & Schmale, 1994;Schmale, 1994a, 1994b;Campbell et al 2001;Schmale et al 2004). Most of the cytotoxic activity of damselfish leucocytes against DNF-derived target cell lines resided in the spleen whilst in the head-kidney it was quite low.…”