Molecular Detection of Bartonella spp. and Hematological Evaluation in Domestic Cats and Dogs from Bangkok, Thailand

Abstract

(1) Background: <i>Bartonella</i> spp. are Gram-negative, facultative, intracellular bacteria transmitted by hematophagous insects. Several species cause zoonotic diseases such as cat-scratch disease. <i>Bartonella henselae</i> and <i>Bartonella clarridgeiae</i> are the main species found in Thailand, however, there have been few studies on <i>Bartonella</i> spp. In addition, the hematological evaluation of <i>Bartonella</i>-infected animals is limited in Thailand. The aims of this study were prevalence investigation and hematological evaluation of <i>Bartonella</i>-infected dogs and cats residing in Bangkok, Thailand. (2) Methods: In total, 295 dogs and 513 cats were molecularly evaluated to detect <i>Bartonella</i> spp. using PCR with primers targeting the partial <i>gltA</i>, <i>rpoB</i>, <i>ftsZ</i>, <i>ribC</i>, and <i>groEL</i> genes. In total, 651 domestic animals were evaluated for hematological parameters compared between <i>Bartonella</i>-positive and <i>Bartonella</i>-negative animals. (3) Results: Overall, the prevalence of <i>Bartonella</i> spp. was 1.61% which was found only in free-ranging cats (2.83%). <i>Bartonella henselae</i> and <i>B. clarridgeiae</i> were confirmed from a concatenated phylogenetic tree of partial <i>gltA</i> and <i>ribC</i> genes, with 100% bootstrapping replication. For other housekeeping gene sequences, mixed infection was expected from the amplicons of <i>rpoB</i>, <i>ftsZ</i>, and <i>groEL</i>. Importantly, the mean corpuscular volume (MCV) was significantly increased in <i>Bartonella</i>-positive cats. (4) Conclusions: We suggest that <i>B. henselae</i> and <i>B. clarridgeiae</i> are important species and are still circulating in domestic animals, especially cats. The evaluation of blood parameters, especially a raised MCV, should be of concern in <i>Bartonella</i> infection in asymptomatic cats. Additionally, the knowledge of how to prevent <i>Bartonella</i>-related diseases should be promoted with people in at-risk situations.