A multi-modal investigation into the prevalence and diagnostic evaluation of vector-borne pathogens and retroviruses in domestic cats throughout Namibia

Abstract

Neglected, but economically significant, tropical diseases may be prevalent in domestic cats of Namibia. A multi-centre prevalence field study was conducted across Namibia to assess the distribution of vector-borne pathogens and retroviruses from domestic cats. Samples of blood and serum from 280 cats in 15 towns across eight regions (22–51 cats per region) were analysed. Screening for Ehrlichia, Anaplasma, Babesia, and Hepatozoon species, as well as feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV), was conducted using light microscopy, point-of-care serology, and quantitative real-time polymerase chain reaction (qPCR) assays. Haematology and serum biochemistry analyses were also performed. Several pathogens were identified in Namibian cats using these diagnostic tools. Comparatively, pathogen detection rates varied by modality, namely light microscopy (5 %), serology (42 %), and qPCR (27 %). More specifically, microscopy revealed an overall prevalence (3 %) for inclusions resembling large Babesia parasites, serology indicated a seroprevalence for FIV antibodies (4 %) and FeLV antigen (40 %), and an overall prevalence determined by qPCR for E. canis (2 %) and H. canis (26 %). The investigation also demonstrated the associations between tick presence, pathogen infection, and disease manifestations in Namibian cats. A particular significant positive association was found between H. canis infection and FeLV antigen seroprevalence (P = 0.005). Overall, the study highlighted the difference of various diagnostic tools for detecting pathogen prevalence in cats. Appropriate diagnostic testing - informed by known associations with disease manifestation - should be key in guiding responsible treatment strategies and evaluating potential zoonotic risks linked to domestic cats of Namibia. HIGHLIGHTS • First comprehensive survey of vector-borne diseases and retroviruses in domestic cats across several Namibian regions. • First confirmed detection of Ehrlichia canis and Hepatozoon canis in domestic feline blood across several regions of Namibia. • Demonstrated significant associations between pathogen infection, tick presence, and disease manifestation.