ORIGINAL PAPER Hepatozoon caimani Carini, 1909 (Adeleina: Hepatozoidae) in wild population of Caiman yacare Daudin, 1801 (Crocodylia: Alligatoridae), Pantanal, Brazil Priscilla Soares 1 & Tarcilla Corrente Borghesan 2 & Luiz Eduardo Rolland Tavares 3 & Vanda Lúcia Ferreira 4 & Marta Maria Geraldes Teixeira 2 & Fernando Paiva 3 Received: 13 January 2017 /Accepted: 30 April 2017 # Springer-Verlag Berlin Heidelberg 2017 Abstract Previous studies showed infections of Hepatozoon caimani in wild populations of caimans in wide regions from Brazil; some of those demonstrated that trophic chain are linked to natural infections through paratenic hosts or by the direct ingestion of vectors. These studies life cycle of H. caimani contributed inestimably to the knowledge of trans- mission routes, yet but lack enhancement tools for better detail of parasite. This study reports the forms in the blood and tissues, and also partial molecular characterization of the H. caimani following part of the 18S rRNA region. In the southern Pantanal, there were sampling 39 adult caimans (Caiman yacare), where 31 (79.5%) were parasitized by H. caimani. Free gametocytes had an average intensity of 19.6% and intraerythrocytic forms 7.42%, in the blood smears. In stained smears of the liver and lungs of naturally infected caimans which were examined, monozoic and dizoic cysts were found in these tissues, generally next to the vessels. In the histopathology, meronts were observed in the wall of vessels from liver and kidney ducts. Blood samples were forwarded to PCR process and produced amplicons with about 600 and 900 bp, respectively, for the primers HEPF300/HEP900 and HEMO1/HEMO2. This was the first report of molecular confirmation of Hepatozoon in popula- tions of naturally infected caimans of morphological detail of the gametocytes in scanning electron microscopy and his- tology of merogony in livers and kidneys of C. yacare. Keywords Apicomplexa . 18S rDNA . Histopathology . Caimans Introduction The suborder Adeleorina is characterized by organisms with a complex life cycle involving one or more asexual cycle, followed by gametogony, sporogony, and syngamy (Barta 2000). In this suborder, the most significant families are Haemogregarinidae, Hepatozoidae, and Karyolysidae; they are mainly a blood para- sitic group generically called Bhemogregarines,^ occurring in fish, reptiles, amphibians, mammals, and birds. The family Hepatozoidae has only one genus Hepatozoon (Barta 2000), first reported in by Miller (1908), H. muris in rats. After this description, others have been published * Priscilla Soares soares_priscilla@yahoo.com.br Tarcilla Corrente Borghesan tarcillacb@usp.br Luiz Eduardo Rolland Tavares lertavares@gmail.com Vanda Lúcia Ferreira vandalferreira@gmail.com Marta Maria Geraldes Teixeira mmgteix@icb.usp.br Fernando Paiva fernando.paiva@ufms.br 1 Programa de Pós-Graduação em Ecologia e Conservação, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil 2 Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil 3 Laboratório de Parasitologia Animal, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil 4 Laboratório de Zoologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil Parasitol Res DOI 10.1007/s00436-017-5467-1