a1 Instituto de Zoologia, Faculdade de Ciencias, Universidade do Porto, 4050 Porto, Portugal.
a2 Centro de Ciencias Biologicas e Geologicas, Universidade da Madeira, Funchal, Portugal.
a3 Museu Municipal do Funchal, Funchal, Portugal.
a4 Kingston University, School of Life Sciences, Kingston, Surrey.
Suspected viral erythrocytic necrosis (VEN) was detected in two specimens of the intertidal fish Mauligobius maderensis (Teleostei: Gobiidae) from Madeira, Portugal. While one host was lightly infected, the other showed intraerythrocytic cytoplasmic inclusions within all mature erythrocytes examined. The inclusions were round to oval, 0·8–2·0 μm in diameter, and most were associated with dense eosinophilic granular areas of various sizes and shapes. Up to three of these granular regions accompanied each inclusion body, but they were sometimes widely separated from it. In a number of infected erythrocytes, a granular halo was observed surrounding the nucleus. The cytoplasm enclosed by the halo often had a different refringence from that outside. None of the 120 other fishes examined from Madeira, representing 43 species of intertidal, pelagic, and deep-sea origin, had detectable infections.