Iridovirus-Like Viruses in Erythrocytes of Lacertids from Portugal

Abstract Icosahedral nucleo-cytoplasmic large DNA viruses (NCLDV)-like viruses, which form inclusions in the erythrocyte cytoplasm of reptiles, were previously presented as candidates for a new genus of theIridoviridaefamily. The present work describes the distribution of infected lizard hosts and ultrastructural characteristics of the viral inclusions of NCLDV-like viruses from Portugal and adjacent locations in Spain. Giemsa-stained blood smears of 235Lacerta schreiberifrom Portugal and Spain, 571Lacerta monticolafrom the mountain Serra da Estrela (Portugal), 794Podarcis hispanicafrom several localities in Portugal and Spain, and 25Lacerta dugesiifrom Madeira Island, were studied. Infection inL. schreiberiwas only found in mountain populations, up to 30% in Serra da Estrela and 9–11% elsewhere. It was absent in lizards from lowlands. Prevalence of infection amongL. monticolain Serra da Estrela was 10%; infected lizards were found during March to July and October but not in August and September. Infection inP. hispanicawas below 3.3%. Only one infected specimen ofL. dugesiiwas identified by light microscopy. Ultrastructural examination of infected samples revealed that the inclusions are virus assembly sites of icosahedral cytoplasmic iridovirus-like virions. Virions from different host species have different ultrastructural features and probably represent different related viruses.