Ticks parasitizing wild mammals in Atlantic Forest areas in the state of Rio de Janeiro, Brazil

Mammals captured in the Serra dos Órgãos National Park (PARNASO) and the Pedra Branca State Park (PBSP) between 2012 and 2015 were examined for the presence of ticks. In total, 140 mammals were examined, and 34 specimens were found to be parasitized by ticks. Didelphis aurita, Akodon montensis and Oligoryzomys nigripes were the species most parasitized. From these specimens, 146 ticks were collected, including 10 larvae. The ticks belonged to eight species: one in the genus Ixodes and seven in the genus Amblyomma. This study reports new associations of ticks and wild mammals in Brazil.


Introduction
Ticks have wide distribution throughout the world, parasitizing a variety of wild and domestic animals and humans (LABRUNA et al., 2005;BARROS-BATTESTI et al., 2006;GUGLIELMONE et al., 2014).These ixodids have direct and indirect impacts on human and animal health by feeding and acting as vectors for pathogenic microorganisms (PAROLA, 2004;BORCHERS et al., 2015).The numbers of studies on the ecology and geographical distribution of ticks that parasitize wild mammals and on transmission of pathogens have been increasing worldwide over the last few years, along with studies on the major zoonotic pathogens they transmit to humans (DE LA FUENTE et al., 2004;PADURARU et al., 2012).
Although there are numerous studies on ticks that are associated with wild mammals in Brazil (e.g.LABRUNA et al., 2005;SARAIVA et al., 2012;MARTINS et al., 2016), there are still gaps that need to be filled.In the state of Rio de Janeiro, there are few studies on this topic, and the records have mainly been on domestic animals (GAZÊTA et al., 2001;LUZ et al., 2014).In this context, the aim of the present study was to report on tick species parasitizing mammals in two areas of the Atlantic Forest
in the state of Rio de Janeiro, thus contributing to improve our knowledge of the host-tick relationships.

Materials and Methods
This study was carried out in preserved areas of the Serra dos Órgãos National Park (PARNASO) (22°30'S 43°07'W, 22°29°S 43°07'W and 22°27'S 43°05'W), altitude 700-1200 meters, and in a sylvatic-urban interface area on the Atlantic Forest Campus of the Oswaldo Cruz Foundation (Campus Fiocruz da Mata Atlântica) (22°56'S 43°24'W and 22°55'S 43°26'W), altitude 30-100 meters, which is a buffer zone of the Pedra Branca State Park (PBSP).In PARNASO hosts were captured in November 2014 and in July 2015 whereas in PBSP they were captured between July 2012 and April 2015 with Sherman  and Tomahawk  traps for small mammals which were sat along transects, at ground level.In addition, ticks of medium-sized and large mammals were also collected from road-killed animals, on the highway that crosses the PARNASO.Trapping effort was of 1200 per period in PBSP totalizing 9600 trap-nights.In PARNASO it was 1800 trap-nights per period totalizing 3600 trap-nights.In PARANSO, 80 pitfall traps were also used per night, totalizing 1600 pitfall-nights.
The animals caught in the traps were anesthetized and euthanized for parasite recovery and for other studies.Mammal species were identified morphologically (REIS et al., 2006;BONVICINO et al., 2008), except for rodent hosts, which were identified by external and cranial morphology, and by cytogenetic analysis (2N and FN) for Oligoryzomys nigripes (Olfers, 1818) and Akodon montensis (Thomas, 1913).Voucher specimens were deposited in the scientific collection of the National Museum of the Federal University of Rio de Janeiro (UFRJ) under access numbers: 83165; 83167; 83170; 83174; 83175 83768-83769; 83998; 83999; 84000-84014.All procedures followed the guidelines for animal capture, handling and care of the Ethics Committee for Animal Use of the Oswaldo Cruz Foundation (license numbers L-39/14 and LW81/12).These animals were captured under authorization from the Chico Mendes Institute for Biodiversity and Conservation (Instituto Chico Mendes de Conservação da Biodiversidade, ICMBio; license numbers 13373 and 45839-2) and by the Environmental Institute of the State of Rio de Janeiro (Instituto Estadual do Ambiente, INEA; license number 020/2011).Biosafety practices and protective equipment were used during all procedures involving animal handling and biological sampling.
The ticks were identified in the Acarology Laboratory of the Federal Rural University of Rio de Janeiro (UFRRJ).Larvae and engorged nymphs, when alive, were kept under 27 o C and 80% humidity in BOD's in order to obtain the respective molts to nymphs and adults.Identification of ticks was based on the following dichotomous keys: Martins et al. (2010) for nymphs; Barros-Battesti et al. (2006) for adults of Amblyomma; and Onofrio et al. (2009) for adults of Ixodes.Tick prevalence and intensity of infestation were calculated as described by Bush et al. (1997).Voucher specimens were deposited in the tick collection "Coleção Nacional de Carrapatos Danilo Gonçalves Saraiva" (CNC) of the FMVZ-USP under the numbers 3655-3658.Nymphs of A. aureolatum and A. ovale were photographed for morphological comparisons (Figure 1), these were photographed under a stereomicroscope (Zeiss Stemi SV 11, Zeiss, Münich, Germany).
Overall, 34/140 (24.3%) mammals were found to be parasitized by adult, nymph and larva of ticks and the average intensity of parasitism was 4.3 ticks per host.All tick species had prevalence greater than 10%, except for A. aureolatum on D. aurita in PARNASO which was recorded in only one out of 13 examined hosts (Table 1).
The arboreal habits of this mammal probably enable parasitism by this tick species as has already been hypothesized by Labruna et al. (2007) for the association of A. longirostre and porcupine rodents.

Figure 1 .
Figure 1.Amblyomma aureolatum (A, C and E) and Amblyomma ovale (B, D and F) infesting wild mammals in the Serra dos Órgãos National Park (PARNASO), Rio de Janeiro.A and B = arrows indicating eye location; C and D = arrows indicating presence of auriculae in the basis capitulum in A. ovale letter D; E and F = arrows indicating spurs of the coxa I.
Species of ticks infesting wild mammals in the Serra dos Órgãos National Park (PARNASO) and Pedra Branca State Park (PBSP): N = nymph, F = female and M = male.EX = number of examined hosts, PA = number of parasitized hosts and P= prevalence (%).Larvae (=10) were identified as Amblyomma sp.