Early Babesia canis transmission in dogs within 24 h and within 8 h of infestation by male Dermacentor reticulatus ticks detached from sheep or dog

Abstract

Background: This study was designed to assess the transmission of Babesia canis to dogs by pre-fed male Dermacentor reticulatus ticks within 8 or 24 h of infestation. Methods & Materials: The experiment was conducted in two steps. In a first trial, donor dogs and donor sheep were infested with Babesia canis infected male and uninfected female Dermacentor reticulatus ticks for 72 h. Attached ticks were subsequently removed, infested on new host dogs and were allowed to attached and feed before removal at 24 h after infestation. In a second trial, the experiment was repeated but the first infestation period was extended to 88 h and the second infestation period with the removed fed ticks shortened to only 8 h on host dogs. The dogs were maintained under clinical surveillance and blood samples were collected for blood smear, IFA and PCR analysis. Results: The tick infection rate was 16.3% (24 h infestation) and 13.7% (8 h infestation). All of the dogs (6 out of 6) were infected after being exposed to pre-fed male ticks for 24 h. Half of the dogs were infected after being exposed to pre-fed ticks for 8 h: 1 out of 3 dogs infested with ticks detached from sheep and 2 out of 3 dogs infested with ticks detached from dog. All the infected dogs were positive to blood smear, IFA and PCR. Conclusion: The results demonstrate the transmission of B. canis by pre-fed male D. reticulatus within 8 h of tick infestation in dogs. Since no minimal transmission time can be established for all possible natural situations, a strategy of prevention based on tick anti-attachment is recommended.