Novel record of a tick Amblyomma sculptum with detection of piroplasm Rangelia vitalii DNA.

Rangelia vitalii is the protozoan responsible for a febrile tick-borne disease known as "Nambiuvú" or "bleeding plague." The only competent vector of this protozoan recognized in Brazil is the tick Amblyomma aureolatum. The aim of this study was to identify R. vitalii using molecular biology in ticks parasitizing Cerdocyon thous from Tijuca and Serra dos Órgãos National Parks, which are areas of the Atlantic Rainforest biome in the municipality of Rio de Janeiro. After taxonomic identification, ticks were crushed and DNA was extracted and examined by polymerase chain reaction (PCR) to verify amplification of a fragment of the 18S rRNA gene of piroplasms. Samples identified as positive in the PCR analysis were subjected to sequencing, which revealed high identity with sequences of R. vitalii. This is the first report of parasitizing nymphs of A. sculptum infected by R. vitalii under natural conditions.

Clinical and hematological evaluation of Rangelia vitalii-naturally infected dogs in southeastern Brazil.

Rangelia vitalii, a tick-borne piroplasm that infects dogs, has been recently molecularly characterized in Brazil, Uruguay and Argentina. Studies on molecular characterization of these piroplasms in different Brazilian regions are scarce. The aim of this study was to evaluate clinical and hematological changes in dogs caused by R. vitalii in the mountainous region of the state of Rio de Janeiro. Blood samples from 36 dogs were evaluated for piroplasms and hematological disorders using light microscopy and molecular analysis. Blood samples from all the animals included in this study were confirmed to be positive for R. vitalii through genetic sequencing. Clinical signspresented by 24 of the 36 dogs of the study were evaluated during appointments or hospitalization within private practice. The most frequent clinical disorders in these dogs that were naturally infected with R. vitalii were fever, spontaneous cutaneous bleeding and diarrhea. Normochromic non-regenerative anemia and thrombocytopenia were the most common hematological disorders in these R. vitalii-positive dogs and therefore should be considered in hematological evaluations on suspected cases.

Clinical and hematological evaluation of Rangelia vitalii-naturally infected dogs in southeastern Brazil / Avaliação clínica e hematológica de cães naturalmente infectados por Rangelia vitalii no sudeste do Brasil

Abstract Rangelia vitalii, a tick-borne piroplasm that infects dogs, has been recently molecularly characterized in Brazil, Uruguay and Argentina. Studies on molecular characterization of these piroplasms in different Brazilian regions are scarce. The aim of this study was to evaluate clinical and hematological changes in dogs caused by R. vitalii in the mountainous region of the state of Rio de Janeiro. Blood samples from 36 dogs were evaluated for piroplasms and hematological disorders using light microscopy and molecular analysis. Blood samples from all the animals included in this study were confirmed to be positive for R. vitalii through genetic sequencing. Clinical signspresented by 24 of the 36 dogs of the study were evaluated during appointments or hospitalization within private practice. The most frequent clinical disorders in these dogs that were naturally infected with R. vitalii were fever, spontaneous cutaneous bleeding and diarrhea. Normochromic non-regenerative anemia and thrombocytopenia were the most common hematological disorders in these R. vitalii-positive dogs and therefore should be considered in hematological evaluations on suspected cases.

Resumo Rangelia vitalii, um piroplasma transmitido por carrapatos que infecta cães, foi sendo recentemente caracterizado molecularmente no Brasil, Uruguai e Argentina. Nas diferentes regiões brasileiras são escassos os estudos acerca da caracterização molecular destes piroplasmídeos. O objetivo deste estudo foi avaliar as alterações clínicas e hematológicas em cães causadas por R. vitalii na região serrana do Rio de Janeiro. Amostras de sangue total de 36 cães foram examinadas quanto à presença de piroplasmas pela microscopia de luz, alterações hematológicas e análise molecular. Todos os cães do presente estudo foram positivos para R. vitalii através do sequenciamento genético. Dos 36 animais positivos para R. vitalii, 24 foram avaliados clinicamente. As alterações mais frequentemente observadas foram febre, sangramento cutâneo espontâneo e diarréia. Anemia normocítica normocrômica arregenerativa e trombocitopenia foram as alterações hematológicas mais observadas em cães positivos para R. vitalii, devendo ser consideradas na avaliação hematológica de cães suspeitos.