Feline Vector-borne Infectious Pathogens

Vector-borne infections are gaining significance due to the changing climate as well as expanding habitats of potential vectors and pathogen reservoirs. Knowledge regarding prevalence, pathogenesis, and clinical significance of feline vector-borne infections is limited. This research retrospectively investigated the percentages of cats tested positive for several vector-borne pathogens (1) in cats in Central Europe tested for Anaplasma phagocytophilum by PCR and/or antibody IFAT, (2) in cats in Germany tested for Hepatozoon spp. by PCR, and (3) in cats in Germany tested by a “Feline Travel Profile”. Asking for stays abroad in this study, Spain was stated as the most prominent country of origin. (4) Therefore, left-over samples of clinically healthy feral cats in Zaragoza without hematological abnormalities were screened for selected vector-borne pathogens by PCR.

(1) Anaplasma phagocytophilum is considered the most significant rickettsial pathogen affecting cats in Central Europe. The frequency of positive molecular and serological test results for Anaplasma phagocytophilum as well as clinical/laboratory abnormalities were evaluated in cats in Germany, Austria, and Switzerland. In total, 244/1636 cats (15%) tested positive by direct (27/725 [4%]) and/or indirect detection methods (21/956 [23%]). The most common clinical signs in PCR-positive cats were lethargy, fever, and thrombocytopenia.

(2) In Germany, Hepatozoon spp. were detected in red foxes and dogs. Data regarding cats is limited. Cats living in Germany and tested for Hepatozoon spp. by PCR were analyzed. 64/931 cats (7%) tested positive for Hepatozoon spp. Sex and age did not have a statistically significant impact. Sequencing revealed Hepatozoon felis in 16 cases. All cats with positive test results and a known travel history had been imported. Leukocytosis, hemoconcentration, and anemia were the most common hematological abnormalities.

(3) In cats living in Germany, a “Feline Travel Profile” was analyzed. At least one pathogen could be detected in 175/624 cats (28%, Ehrlichia spp. IFAT 12%, Leishmania spp. IFAT 4%, Hepatozoon spp. PCR 9%, Dirofilaria spp. 0.2%, Rickettsia spp. IFAT 11%). Spain was stated as the most prominent country for importing cats to Germany.

(4) Feral cats from Spain were screened by PCR for selected vector-borne pathogens. 158/332 cats tested positive (48%, Hepatozoon spp. 25.6%, hemotropic Mycoplasma spp. 22.9%, Bartonella spp. 9.3%, Leishmania spp. 2.1%). Male sex and FeLV-/FIV-infections had a statistically significant impact on test results.

Feline vector-borne infections are gaining significance and should be considered as potential differential diagnosis in cats with clinical signs and hematological abnormalities suspicious for these infections.