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.

In Brazil, except for the broad study by Pontes et al. (2009) involving ticks associated with a community of snakes in the Atlantic Forest, most studies have been limited to recording parasitism of reptiles by ticks in random samples, usually restricted to a few individual specimens (LABRUNA et al., 2002(LABRUNA et al., , 2005DANTAS-TORRES et al., 2005MARTINS et al., 2007;LOPES et al., 2010), studies involving captive hosts (see review in GUGLIELMONE; NAVA, 2010), or characterization of the life cycle of ticks Amblyomma dissimile or A. rotundatum under experimental conditions (ARAGÃO, 1912;OBA;SCHUMAKER 1983;FREITAS et al., 2004;RODRIGUES et al., 2010).
Current knowledge concerning infestation by Amblyomma in wild reptiles is still limited, and thus, the present study makes a contribution through recording parasitism by the tick A. rotundatum on reptiles in a restinga habitat, the Grussaí restinga, in the northern region of the state of Rio de Janeiro.
The study was conducted during December 2010 and January 2011, in a restinga remnant in the municipality of São João da Barra (21° 44' 10.20" S and 41° 1' 53.39" W), state of Rio de Janeiro, Brazil. Restingas are habitats consisting of dunes and sandy plains covered with xerophytic herbaceous vegetation and shrubs that occur along the coast of Brazil (EITEN, 1992). The climate is tropical subhumid and semi-arid, with a mean annual rainfall ranging from 800 to 1,200 mm and higher incidence of rainfall during the summer months and lower in winter (BRASIL, 1983).
The lizards were caught with the aid of compressed air rifles, while the snakes were caught manually. Animals that were still alive were euthanized by means of ethyl ether inhalation and were carefully examined for the presence of ticks on every part of the body.
All the ticks detected were collected manually or with forceps, stored in alcohol (70° GL), identified and deposited in the collection of the National Reference Laboratory of Vectors of Rickettsial diseases, FIOCRUZ, under access numbers Ixo 1482, Ixo 1483 and Ixo 1484, for the specimens collected from Philodryas olfersii, Ameiva ameiva and Tropidurus torquatus, respectively. The keys developed by Aragão and Fonseca (1961) and Martins et al. (2010) were used to identify adults and nymphs, respectively.
A total of 131 individual specimens from nine reptiles species were sampled (Table 1). The only tick species identified was A. rotundatum, at low intensities. One adult female was found on the ventral region of the lizard A. ameiva (frequency = 10%, n = 10) ( Figure 1b) and one nymph on the lizard T. torquatus (frequency = 2%, n = 51). Four nymphs was detected on one specimen of the snake P. olfersii (established under its scales), corresponding to a frequency of 50%, although this value was based on only two individuals of this snake species (Figure 1a, Table 1).
Although the tick A. rotundatum is considered to be a common species on ectothermic vertebrates (GUGLIELMONE; NAVA, 2010), the present study is the first formal scientific record of this tick species parasitizing the reptiles T. torquatus and P. olfersii. Analysis on the data obtained indicated that the frequency and intensity of infestation by A. rotundatum in this community of reptiles sampled in the Grussaí restinga habitat was low. The only previous information available regarding infestation by A. rotundatum in a community of reptiles in nature comes from the study by Pontes et al. (2009), who reported comparatively higher frequency and intensity of infestation in a community of snakes in an area of dense tropical rainforest in the Atlantic Forest located in Serra do Mendanha in the state of Rio de Janeiro. The scarcity of knowledge concerning A. rotundatum infestation on reptiles in nature makes it difficult to determine to what extent the differences in frequency and intensity observed are due to differences in the types of environments studied (rainforest and restingas).
The only information regarding infestation by ticks of the genus Amblyomma on A. ameiva is in relation to identification of A. dissimile in Venezuela (DIAZ-UNGRIA, 1957) and in Trinidad and Tobago (AITKEN et al., 1968). Recently, A. dissimile was also recorded infesting an individual of A. ameiva in the state of Maranhão, Brazil (LOPES et al., 2010). Amblyomma rotundatum has been reported on A. ameiva, but without location information . Lainson et al. (2007) demonstrated the vector function of A. rotundatum in relation to transmission of the protozoan hemoparasite Hemolivia stellata between the anuran Rhinella marina and the lizard A. ameiva.
Previous records of A. rotundatum parasitizing T. torquatus are restricted to the use of this and other species of reptiles under experimental conditions, to study the biological cycle of the tick (ARAGÃO, 1912;FREITAS et al., 2004). Labruna et al. (2005) reported an occurrence of a male A. rotundatum in the Amazon region parasitizing Tropidurus sp., probably T. oreadicus, since T. torquatus does not occur in the region (SENA et al., 2008). In the state of Pernambuco, northeastern Brazil, a lizard of the genus Tropidurus parasitized by two nymphs of Amblyomma sp. was recorded in the Dois Irmãos State Park (DANTAS-TORRES et al., 2010), and also an individual of T. hispidus infested by three nymphs  v. 21, n. 3, jul.-set. 2012 New host records for Amblyomma rotundatum from Grussaí restinga, Rio de Janeiro, Brazil 321 of A. dissimile (DANTAS-TORRES et al., 2008). Tropidurus hispidus was also found infested by Amblyomma sp. in Venezuela (PRIETO, 1980). The only record of parasitism by ticks on the snake P. olfersii was reported by Lizaso (1984). This author observed infestation by Amblyomma sp. during fauna rescue at the Água Vermelha hydroelectric plant, on the borders of the states of São Paulo and Minas Gerais, Brazil. During a study to determine occurrences of ticks on snakes in the Serra do Mendanha, state of Rio de Janeiro, two individuals of P. olfersii were found to be negative for the presence of ticks (PONTES et al., 2009). However, in the same study, individuals of the sympatric snakes Chironius laevicollis, Spilotes pullatus and Xenodon neuwiedii presented infestation by A. rotundatum. Dantas-Torres et al. (2010) reported parasitism of a snake of the genus Philodryas by a nymph of Amblyomma sp. collected in the Dois Irmãos State Park in the state of Pernambuco.
In conclusion, this study extends the list of reptilian hosts for the tick A. rotundatum. Analysis of the results obtained suggests that in the Grussaí restinga habitat, A. rotundatum uses different species of reptiles to complete its life cycle. Considering the biological capacity of A. rotundatum to transmit blood-borne protozoa to reptiles and amphibians, and the previous findings of natural infection by Rickettsia bellii in the state of Rondonia (LABRUNA et al., 2004), additional studies in the Grussaí restinga could provide an important opportunity to elucidate the parasite ecology of the wildlife community in this region.