We have shown that nasal immunization with an Ad5-based vaccine can induce a long-term protective immune response against Ebola virus in a mouse model which is not impeded by preexisting immunity to adenovirus serotype 5. While these results are extremely encouraging, further characterization of the immune response against both the encoded antigen and the adenovirus vector in larger, clinically relevant animal models is vital for both understanding the biology of Ad vaccines and for the development of an effective Ebola vaccine suitable to populations with different requirements [57, 58] . The issue of pre-existing immunity must also be adequately addressed in order to develop efficient recombinant adenovirus-based vaccines. While the majority of the literature suggests that pre-existing immunity significantly hamper the effective use of AdHu5 vaccine carriers, other investigators have reported that pre-existing immunity did not interfere with the potency of recombinant Ad5-based vaccines in both pre-clinical models of disease and in humans [59, 60] . Thus, additional studies identifying clinically relevant conditions under which to test Ad-based vaccine candidates are necessary to assess the full impact of pre-existing immunity on vaccine potency, including in different compartments. Better define the role of preexisting immunity on vaccine-induced immunity will further the understanding of how individuals previously exposed to adenovirus will respond to these immunization regimens. Screening Pneumonia Patients for Mimivirus Acanthamoeba polyphaga mimivirus (APM), a virus of free-living amebae, has reportedly caused human respiratory disease. Using 2 newly developed real-time PCR assays, we screened 496 respiratory specimens from 9 pneumonia-patient populations for APM. This virus was not detected in any specimen, which suggests it is not a common respiratory pathogen. I nvestigation of a suspected Legionnaire's pneumonia outbreak in 1992 led to the isolation of a new microorganism from a water cooling tower in Bradford, England. This pathogen was thought to be a bacterium because it resembled small gram-positive cocci; however, in 2003 it was correctly identifi ed as a virus (1) . Acanthamoeba polyphaga mimivirus (APM), named for its ameba host and bacteria-mimicking characteristics, is a double-stranded DNA virus with the largest viral genome described to date (1.2 Mb) (2) . Mimiviridae is the newest member of the nucleocytoplasmic large DNA virus (NCLDV) group, which also contains Poxviridae, Iridoviridae, Asfarviridae, and Phycodnaviridae (1) . APM encodes specifi c translation proteins that are more commonly associated with cellular organisms than with viruses (2) .