title: Detection of antibodies against Anaplasma phagocytophilum in Algerian mice (Mus spretus), Portugal.
abstract: The recent detection of Anaplasma phagocytophilum in Portugal stimulated further research on the agent's enzootic cycle, which usually involves rodents. Thus a total 322 rodents belonging to five species, including 30 Apodemus sylvaticus (wood mouse), 65 Mus musculus (house mouse), 194 M. spretus (algerian mouse), 5 Rattus norvegicus (brown rat) and 28 R. rattus (black rat), were studied by indirect immunofluorescent assay (IFA) and/or polymerase chain reaction (PCR) for A. phagocytophilum exposure in four sampling areas of mainland and two areas of Madeira Island, Portugal. Overall, 3.6% (7/194) of M. spretus presented with IFA-positive results. Seropositive mice were detected in all three mainland sampling areas where this species was captured, with prevalence of 5.2% (5/96) and 5.0% (1/20) for the Ixodes-areas of Arrábida and Mafra, and 1.3% (1/78) for Mértola, a difference that was not statistically significant (p > 0.05). The majority of IFA-positive mice were detected in spring when considering either Arrábida alone (p = 0.026) or all M. spretus sampling areas together (p = 0.021), although the significance of this association was not evident after Bonferroni correction. Nevertheless, neither the seropositive M. spretus, nor additional samples of 10% seronegative rodents from mainland, and 16% of rodents collected in Madeira Island showed evidence of A. phagocytophilum active infections when spleen and/or lung samples were tested by PCR. Either the M. spretus results represents residual antibodies from past A. phagocytophilum infections, present infections with limited bacteremia, or cross-reactions with closely related agents deserves more investigation.
authors.affiliation: Centro de Estudos de Vectores e Doenças Infecciosas, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisboa, Portugal. ana.santos@insa.min-saude.pt
authors.forename: A S
authors.initials: AS
authors.lastname: Santos
authors.forename: F
authors.initials: F
authors.lastname: Amaro
authors.forename: M M
authors.initials: MM
authors.lastname: Santos-Silva
authors.forename: R
authors.initials: R
authors.lastname: De Sousa
authors.forename: M L
authors.initials: ML
authors.lastname: Mathias
authors.forename: M G
authors.initials: MG
authors.lastname: Ramalhinho
authors.forename: M S
authors.initials: MS
authors.lastname: Nuncio
authors.forename: M J
authors.initials: MJ
authors.lastname: Alves
authors.forename: F
authors.initials: F
authors.lastname: Bacellar
authors.forename: J S
authors.initials: JS
authors.lastname: Dumler
mesh_terms: D041081:Anaplasma phagocytophilum / Q000276:immunology / Q000302:isolation & purification*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D017931:DNA Primers; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D008297:Male; D051379:Mice / Q000097:blood / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D011174:Portugal; D051381:Rats / Q000097:blood / Q000382:microbiology*
chemical_list: D000907:Antibodies, Bacterial; D017931:DNA Primers