Experimental infection of lacertids with lizard erythrocytic viruses

Objective: Lizard erythrocytic viruses (LEVs) produce inclusions in the cytoplasm of erythrocytes, but their impact on the infected host is poorly understood. This work reports on an experimental study of the infection process in Lacerta monticola and Lacerta schreiberi from Serra da Estrela Mountain, Portugal. Methods: A time sequence light microscope and transmission electron microscope (TEM) study of the infection process was performed in peripheral blood erythrocytes of experimentally infected lizards. Virions were searched for by TEM in visceral organs and bone marrow of the animals. Results: Infection was usually restricted to erythrocytes, but occasionally became systemic and induced disease. In the first case, a prevalence of infected erythrocytes of up to 98% followed by recovery was observed. In the latter, infection spread to leukocytes, leading to the death of the infected animals. Conclusions: The potential of LEVs to induce systemic infections was demonstrated. Sequential TEM examination of LEV-infected cells is described for the first time, demonstrating features such as dense inclusions related to virus nucleoid formation, intranuclear virions, intermediate structures in virion capsid morphogenesis and virus release by budding.