Rangelia spp

From Dog
A dog with clinical signs of Rangeliosis, characterized by massive bleeding from the skin covering the dorsal surface of the pinna[1]

Rangeliosis (Nambiuvú - 'bloody ears') is a tick-borne zoonotic intra-erythrocytic ampicomplexan protozoan parasite of dogs caused by Rangelia vitalii[2].

Rangelia spp are phylogenetically related to Babesia spp, and this parasite is highly prevalent in young hunting dogs in south and southeast regions of Brazil[3], thought to be transmitted by Rhipicephalus sanguineus[4] and Amblyomma aureolatum.

Following transmission of the parasite by ticks, a circulating parasitemia is observed in dogs which peaks between 9 - 11 days, with the parasite infecting not only erythrocytes, but also leucocytes and endothelial cells[5]. Subsequently, the parasitemia becomes reduced due to inflammatory cytokine release[6] and the protozoan can be observed in circulating leukocytes 17 - 21 days post-infection[7].

Affected dogs primarily present with lethargy, fever and anorexia, but other symptoms such as dyspnea, petechiae, hematemesis, bloody diarrhea, splenomegaly, hepatomegaly, lymphadenopathy. icterus and bilirubinuria may also exist. A characteristic feature of this disease is hemorrhage in the gastrointestinal tract, and persistent bleeding from the nose, oral cavity and tips, margins and outer surface of the pinnae[8].

The disease usually progresses with the presence of intracytoplasmic parasitophorous vacuoles in the endothelial cells of capillaries of various organs and tissues and inflammatory infiltrate in organs such as the kidneys, heart and liver[9].

Blood tests usually reveal leukopenia due to neutropenia and eosinopenia[10], along with lymphocytosis, monocytosis and a regenerative immune-mediated hemolytic anemia[11] and thrombocytopenia[12], although hypoalbuminemia, hyperglobulinemia[13] and elevated levels of ALT, AST and creatine kinase are commonly observed.

Alterations in blood levels of copper, iron and zinc have also been noted[14], thought to be a result of a state of redox unbalance[15].

Diagnosis is based on microscopic visualization of piroplasms obtained from bone marrow samples (parasite not usually visible in peripheral blood).

A differential diagnosis would include babesiosis, ehrlichiosis, leishmaniasis and leptospirosis.

A definitive diagnosis requires PCR exclusion of other blood parasites such as Babesia spp.

Many urban dogs, which are the majority exposed to this parasite, may succumb to infection without veterinary intervention.

Treatment is usually effective with antiprotozoal drugs such as diminazene aceturate or imidocarb diproprionate[16].

Supportive therapy such as intravenous fluids and blood transfusions should be employed when necessary.


  1. Open Access Biomedical
  2. Da Silva AS et al (2013) Canine rangeliosis: the need for differential diagnosis. Parasitol Res 112(3):1329-1332
  3. Lemos TD et al (2012) Detection and molecular characterization of piroplasms species from naturally infected dogs in southeast Brazil. Rev Bras Parasitol Vet 21(2):137-142
  4. Boozer AL & Macintire DK (2003) Canine babesiosis. Vet Clin North Am Small Anim Pract 33:885-904
  5. Soares JF et al (2011) Detection and molecular characterization of a canine piroplasm from Brazil. Vet Parasitol 180(3-4):203-208
  6. Paim FC et al (2013) Increased Cytokine and Nitric Oxide Levels in Serum of Dogs Experimentally Infected with Rangelia vitalii. Korean J Parasitol 51(1):133-137
  7. Da Silva AS et al (2011) Experimental infection with Rangelia vitalii in dogs: acute phase, parasitemia, biological cycle, clinical-pathological aspects and treatment. Exp Parasitol 128(4):347-352
  8. Loretti AP & Barros SS (2005) Hemorrhagic disease in dogs infected with an unclassified intraendothelial piroplasm in southern Brazil. Vet Parasitol 134(3-4):193-213
  9. Fighera RA et al (2010) Patogênese e achados clínicos, hematológicos e anatomopatológicos da infecção por Rangelia vitalii em 35 cães (1985-2009). Pesq Vet Bras 30(11):974-987
  10. França RT et al (2013) Hematologic and bone marrow changes in dogs experimentally infected with Rangelia vitalii. Vet Clin Pathol 42(1):31-39
  11. Paim CB et al (2012) Activities of ectonucleotidases and adenosine deaminase in platelets of dogs experimentally infected with Rangelia vitalii. Exp Parasitol 131(2):252-257
  12. Paim CB et al (2012) Thrombocytopenia and platelet activity in dogs experimentally infected with Rangelia vitalii. Vet Parasitol 185(2-4):131-137
  13. Paim FC et al (2013) Serum proteinogram, acute phase proteins and immunoglobulins in dogs experimentally infected with Rangelia vitalii. Vet Parasitol 192(1-3):137-142
  14. Da Silva AS et al (2012) Influence of Rangelia vitalii (Apicomplexa: Piroplasmorida) on copper, iron, and zinc bloodstream levels in experimentally infected dogs. J Parasitol 98(5):1018-1020
  15. França RT et al (2012) Relationship between oxidative stress and clinical-pathological aspects in dogs experimentally infected with Rangelia vitalii. Res Vet Sci 93(3):1309-1313
  16. Costa MM et al (2012) Rangelia vitalii: changes in the enzymes ALT, CK and AST during the acute phase of experimental infection in dogs. Rev Bras Parasitol Vet 21(3):243-248