Lúcio André Viana

Hepatozoon caimani (Apicomplexa: Hepatozoidae) in Wild Caiman, Caiman yacare, from the Pantanal Region, Brazil

Abstract The prevalence and parasitemia of Hepatozoon caimani in the natural population of the caiman, Caiman yacare, from the Pantanal area, state of Mato Grosso do Sul, central Brazil, were evaluated according to gender and month of capture from July 2006 to February 2008. Blood samples were obtained bimonthly from a total of 229 caimans, and 76% were positive. Prevalence varied significantly according to sampling month and animal size. Almost all adults (100%) and young-adults (97%) were positive, while 63% of juvenile caimans were positive and all of the youngest individuals were negative. These results indicate that caimans are infected for the first time as juveniles. The mean parasitemia in blood was 13.5 ± 13.0 (n  =  174; 1–96 parasites) and did not significantly vary with respect to gender, month of sampling, size, or weight of the caiman. The frequency distribution of parasites in the caiman population was aggregated. Differences in feeding habits and exposure to vectors between the youngest caimans and juveniles are hypothesized as the main risk factors for caimans to acquire H. caimani in central Brazil.

New host records for Amblyomma rotundatum (Acari: Ixodidae) from Grussaí restinga, Rio de Janeiro, Brazil

Amblyomma rotundatum Koch is a parthenogenetic tick usually associated with reptiles and amphibians. However, relatively few studies on occurrences of ticks in wild reptile populations in Brazil have been produced. The aim of this study was to analyze the presence of ticks associated with reptile species in the Grussaí restinga, in the municipality of São João da Barra, state of Rio de Janeiro, Brazil. Between December 2010 and January 2011, 131 individuals belonging to nine species of reptiles of the order Squamata were sampled: the lizards Tropidurus torquatus (n = 51), Hemidactylus mabouia (n = 25), Mabuya agilis (n = 30), Mabuya macrorhyncha (n = 6), Cnemidophorus littoralis (n = 5) and Ameiva ameiva (n = 10); and the snakes Philodryas olfersii (n = 2), Oxyrhopus rhombifer (n = 1) and Micrurus corallinus (n = 1). The only tick species found to be associated with any of the reptiles sampled was A. rotundatum. One adult female was detected on one individual of the lizard A. ameiva, one nymph on one individual of the lizard T. torquatus and four nymphs on one individual of the snake P. olfersii. This study is the first record of parasitism of A. rotundatum involving the reptiles T. torquatus and P. olfersii as hosts. Our results suggest that in the Grussaí restinga habitat, A. rotundatum may use different species of reptiles to complete its life cycle.

Parasitization by Sauroplasma sp. (Apicomplexa: Haemohormidiidae) in Chelonian Podocnemis expansa (Testudines: Podocnemididae) in the Brazilian Amazon

Abstract The prevalence and parasitemia of the piroplasm Sauroplasma sp. were evaluated in the Amazon chelonian Podocnemis expansa in Brazil. Samples were collected from 75 chelonians from 3 locations, including a commercial breeding facility, an indigenous subsistence breeding facility, and a wild population. Sauroplasma were found in 72% (54/75) of the chelonians, and the prevalence varied among the sampling sites. No significant correlations were found between the prevalence and the sex and body condition index of the chelonians. The mean parasitemia rate was 44.14/2,000 erythrocytes (2.2%), and no significant correlation was found between the parasitemia and sex and body condition index of the chelonians. These results suggest that the parasite is not pathogenic to P. expansa. No ectoparasites were found in the animals evaluated in the present study; however, due to the aquatic habit of the chelonian, it is likely that the piroplasm is transmitted by leeches and not by ticks, as would be expected for piroplasms.

Caryospora bigenetica (Apicomplexa: Eimeriidae) in South America: new hosts and distribution records.

The coccidian Caryospora bigenetica was first described in the snake Crotalus horridus (Viperidae) from United States of America. This study represents the first record of the occurrence of C. bigenetica in snakes in South America. Feces were sampled between November 2013 and May 2014 from 256 wild snakes maintained in scientific breeding facilities in the states of Mato Grosso do Sul (MS; n = 214) and Rio de Janeiro (RJ; n = 42), Brazil. Caryospora bigenetica was found in 14 (5.6%) snakes, all belonging to the family Viperidae. Ten Bothrops moojeni and two Crotalus durissus from MS were infected. The coccidian was also found in one C. durissus and in one Bothrops jararacussu from the state of RJ. The oocysts were spherical with a double wall, the exterior lightly mammillated, striations apparent in transverse view, 13.0 µm (12 - 14); polar granule fixed in the internal wall. Sporocysts oval or pyriform, 10.0 × 8.0 µm (9 - 11 × 8 - 9); Stieda body discoid; sub-Stieda body present; sporocyst residuum present, formed by a group of spheroid bodies between sporozoites. This study increases the number of viperid hosts of C. bigenetica and expands the geographical distribution to South America.

Eimeria spp. (Apicomplexa: Eimeriidae) in Black Caiman Melanosuchus niger (Crocodilia: Alligatoridae) from the Amazon Region, Brazil, with a Description of Two New Coccidian Species

During November 2011, faeces from 23 black caimans (Melanosuchus niger) were collected from the Brazilian Amazon, and coccidians were found in 83% of the individuals examined. Three Eimeria species were found in the black caiman faeces, two of which were recognised as new species and are subsequently described in the present study. Eimeria paraguayensis was found in 17 of 23 animals sampled. Eimeria nigeri n. sp were found in 16/23 animals examined. Oocysts were spherical to sub-spherical, 29.2 × 28.1 (23-32 × 23-30) µm, and 12.1 × 11.0 µm spherical oocyst residuum was present. Sporocyst was ovoid, 15.5 × 9.7 (8-11 × 12-17) µm, and had a Stieda body at a slightly pointed end. The sporocyst residuum consisted of a compact mass of refractile granules. Eimeria portovelhensis n. sp. were found in 16/23 animals examined. Oocysts were spheroidal, 19.5 × 19.1 (16-21) µm, and had 9.0 × 7.8 µm spherical oocyst residuum present. The spindle-shaped sporocysts were 11.0 × 4.0 (8-13 × 2-5) µm and had two apparent Stieda bodies, one at each pole and with one filament curved at each pole. Sporocyst residuum was present, with four or five small refractile granules. The two new species are differenti - ated from the five species of Eimeria recorded within the crocodilian family Alligatoridae.