Hematological characteristics of autochthonous hypermicrofilaremic dirofilariosis in dogs in Kannur District of Kerala

This study aimed to determine whether autochthonous high-intensity D. repens microfilaremia leads to haematological changes in companion dogs. Dogs with hypermicrofilaremia presented to the District Veterinary Centre, Kannur were selected for the study. A total of 100 dogs were positive for hypermicrofilariaemia with D. repens based on peripheral blood smear examination and Knott's test. Of these, 3 dogs were concurrently positive for sheathed microfilaria (MF) of Brugia spp. Interestingly, an adult live worm of D. repens approximately eight cm in length was detected on a subcutaneous mass on the hind limb of a hypermicrofilaremic dog in the study. We compared the hematological parameters of 100 autochthonous hypermicrofilaremic dogs and 15 uninfected dogs. The hematological findings in the study are mild to moderate anemia, moderate to severe thrombocytopenia, leucocytosis with granulocytosis, lymphocytosis and monocytosis as compared to the uninfected group of dogs. The pathogenicity of naturally occurring hypermicrofilaremia is poorly studied, and knowledge of its epidemiology, host-parasite relationship and impact on various organs is warranted for better prevention and control, especially in hot-spot areas.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12639-023-01622-6.

Hematological alterations in large Babesia species infection in dogs of Kannur District of Kerala

Canine babesiosis is a tick-borne disease caused by apicomplexan intraerythrocytic hemoprotozoan parasites. It is caused by the small (Babesia gibsoni, B. conradae, and B. vulpes) and large (B. vogeli, B. canis, and B. rossi) Babesia groups. As per the recent reports, the most prominent Babesia species encountered in the Kerala state are the small Babesia, B. gibsoni followed by the large Babesia, B. vogeli. The latter is regarded as mildly pathogenic, causing subclinical or mild disease; however severe complications like systemic inflammatory response syndrome, multiple organ dysfunction syndrome, etc. have also been reported. The information on the status of hematological alterations in naturally infected dogs with large Babesia is lacking, particularly from the state of Kerala. The present study involves a retrospective study of clinical cases of large Babesia infection in dogs. The complete haematological profile from well-documented laboratory records of 4039 dogs suspected for babesiosis presented to District Veterinary Centre, Kannur during the period from December 2018 to October 2020 was analyzed for the study. Natural infections were recorded in 35 (0.87%) dogs based on the presence of intraerythrocytic piroplasm of large Babesia spp. by light microscopic examination of Giemsa-stained blood smears. The most consistent features observed were mild to moderate regenerative, normocytic and normochromic anemia, lowered to normal neutrophil count and thrombocytopenia. In comparison to hemolytic anemia, thrombocytopenia was the most frequent clinicopathological finding in the study with an increased presence of large activated platelets or macro-platelets.