Completing the Puzzle: A Cluster of Hunting Dogs with Tick-Borne Illness from a Fishing Community in Tobago, West Indies

Abstract

Eight hunting dogs were visited by a state veterinarian on the island of Tobago, Trinidad and Tobago, West Indies, as owners reported anorexia and paralysis in five of their dogs. The veterinarian observed a combination of clinical signs consistent with tick-borne illness, including fever, anorexia, anaemia, lethargy and paralysis. Blood and ticks were collected from each dog and submitted to a diagnostic laboratory for analysis. Microscopic analysis revealed a mixed infection of intracytoplasmic organisms consistent with Babesia spp. (erythrocyte) and Ehrlichia spp. (monocyte), respectively, from one dog, while a complete blood count indicated a regenerative anaemia (n = 1; 12.5%), non-regenerative anaemia (n = 4; 50%), neutrophilia (n = 3; 37.5%), lymphocytosis (n = 2; 25%), thrombocytopaenia (n = 3; 37.5%) and pancytopaenia (n = 1; 12.5%). DNA isolated from the eight blood samples and 20 ticks (16 Rhipicephalus sanguineus and 4 Amblyomma ovale) were subjected to conventional PCR and next-generation sequencing of the 16S rRNA and 18S rRNA gene for Anaplasma/Ehrlichia and Babesia/Theileria/Hepatozoon, respectively. The DNA of Ehrlichia spp., closely related to Ehrlichia canis, was detected in the blood of three dogs (37.5%), Anaplasma spp., closely related to Anaplasma marginale, in two (25%), Babesia vogeli in one dog (12.5%) and seven ticks (35%) and Hepatozoon canis and Anaplasma spp., in one tick (5%), respectively. These findings highlight the need to test both the vector and host for the presence of tick-borne pathogens when undertaking diagnostic investigations. Further studies are also warranted to elucidate the susceptibility of canids to Anaplasma marginale.

Viruses of free-roaming and hunting dogs in Uganda show elevated prevalence, richness and abundance across a gradient of contact with wildlife

“…and Uncinaria spp. ), which is endemic in the region [75], or by protozoan parasites of blood cells, such as reported for hunting dogs in Tobago [76]. Our observation that WBCs were higher in dogs from Bundibugyo and Kabarole districts than in dogs from Wakiso District may reflect a higher burden of infectious disease or higher rates of generalized inflammation (e.g.…”

Application of Next-Generation Sequencing (NGS) Techniques for Selected Companion Animals

“…Charles et al used this diagnostic tool to perform full diagnostic of etiology agents in dogs with tick-borne illness [ 76 ]. Blood and tick samples were collected from each dog and sent to a diagnostic laboratory for analysis.…”

“…Babesia vogeli was detected in one dog and seven ticks, while Hepatozoon canis and Anaplasma spp. were found in one tick [ 76 ]. Through NGS, the exact species of these pathogens and their phylogenetic origins could be determined.…”