Experimental and Applied Acarology 25: 909 916, 2001. 2002 Kluwer Academic Publishers. Printed in the Netherlands. Ticks (Acari: Ixodidae) associated with domestic dogs in Franca region, São Paulo, Brazil MATIAS PABLO JUAN SZABÓ 1,2,, TIAGO MARQUEZ CUNHA 1, ADRIANO PINTER 3 and FERNANDO VICENTINI 1 1 Faculdade de Medicina Veterinária, Universidade de Franca, Brazil 2 Departamento de Patologia Veterinária, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, Universidade Estadual Paulista, Brazil 3 Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Brazil (Received 31 January 2002; accepted 17 June 2002) Abstract. Ticks on 140 domestic dogs from both urban and rural areas of Franca region in São Paulo state were identified with 102 dogs from urban areas and 38 from rural areas. Of urban dogs, 27.5% were infested exclusively by Rhipicephalus sanguineus ticks. Of the rural dogs, 36.8% were infested with the following tick species: R. sanguineus, Boophilus microplus, Amblyomma ovale and A. cajennense. Mixed infestations included a dog hosting A. cajennense and A. ovaleand another with B. microplus and R. sanguineus. The most intense infestations were detected on urban dogs. Hemolymph tests of these ticks performed to detect rickettsial or Borrelia bacteria yielded negative results. Key words: Ixodidae, tick, domestic dog, Franca region, São Paulo, Brazil Introduction Dogs have been domesticated for at least 10,000 years and have spread globally with humans. The close proximity between man and dog potentially permits the sharing of parasites. It is also possible that dogs carry to the domestic environment parasites picked up in nature. In such a context ticks are of major concern for public health. Brazil is a huge country with an area of 85,474,035 km 2 and 172,000,000 inhabitants and information on ticks species that infest dogs is scarce. The few existing observations indicate that Rhipicephalus sanguineus is the main species found in this host (Massard et al., 1981; Vianna and Bittencourt, 1995; Author for correspondence: Departamento de Patologia Veterinária, FCAVJ-UNESP, Via de Acesso, Prof. Paulo Donato Castellane, s/n-cep 14884-900, Jaboticabal, SP, Brazil (Tel.: +55-016-3209-2662; Fax: +55-016-3202-4275; E-mail: szabo@asbyte.com.br, szabo@fcav.unesp.br)
910 Ribeiro et al., 1997). But the predominance of R. sanguineus seems to be restricted to the urban environment (Labruna and Campos Pereira, 2001). Dogs from rural areas, with unrestricted movement and possible sharing of environment with other domestic and wild hosts, are infested mainly by Amblyomma species (Labruna and Campos Pereira, 2001). Amblyomma species infesting dogs include A. aureolatum, A. ovale, A. oblongoguttatum, A. cajennense, A. tigrinum (Kohls, 1956; Ribeiro, 1966/1967; Massard et al., 1981; Vianna and Bittencourt, 1995; Ribeiro et al., 1997; Evans et al., 2000; Labruna et al., 2000, 2001) among others. It is very probable that in such a big country and according to local hosts and environmental characteristics Amblyomma species infesting dogs vary from place to place. This has recently been exemplified by the predominance of the tick A. oblongoguttatum in rural dogs from Uruará, eastern Amazon, Brazil (Labruna et al., 2000). On the other hand it is surprising that information on dog ticks from São Paulo, the most industrialized state of Brazil, is lacking. The present work thus presents data on ticks infesting dogs from urban areas in Franca municipality, São Paulo, Brazil and farms of that region. Material and Methods Location of the study and local characteristics Franca is located in the northeast of the state of São Paulo (20 32 03 S, 47 24 19 WGR) bordering Minas Gerais State. It is 401 km distant from the state capital, São Paulo and the area of the municipality covers 603 km 2,atan average altitude of 1040 m. Its rural population is estimated at 8469 and the urban population at 273,863 inhabitants. Franca has a tropical high-altitude climate, with an average annual temperature of 23.5 C and a rainfall of 35 mm in the driest month. The rainy months are from December to February, with 50% of the annual rainfall, from 1400 to 1500 mm. The prevailing winds are from the northeast or southeast and are fairly constant. Relative air humidity is usually around 70%. Main economic activities include production of milk, honey, coffee, leather, and shoes. The dog population is estimated at 36,000. Data collection Ticks from dogs were collected in urban and rural areas. In the city of Franca ticks were collected during the rabies vaccination campaign of 2000 (26th of August and 2nd of September) at seven different districts covering most of the city: Jardim Aeroporto-III, Jardim Planalto, Jardim Dermínio, Jardim Palma, Jardim Noêmia, Jardim Francano, and Parque Leporace I. Rural collections were from farms or small rural properties, 11 from Franca municipality and other 11 from neighboring municipalities (Claraval, Patrocínio
911 Paulista, Restinga Ribeirão Corrente, and São José da Bela Vista). Franca and all these neighboring municipalities belong to Franca rural development assistance region (CATI) from São Paulo state. Collections in rural areas were performed in 2001 (15 17th, 19th of January, and 30th of March). At first, permission for tick collection was asked of the owners and after that a through examination of approximately 5 min was performed on each dog to look for ticks. A tick infestation level score was set up as follows: 0 (no tick found); + (1 10 ticks); ++ (11 100 ticks); +++ (>100 ticks). At the same time a small questionnaire was filled in to obtain a proper identification of the dog, information about its usual environment, movement range, acaricide treatments, and coexistence with other hosts. Only adult tick samples were collected for identification. Hemolymph test Hemolymph test was performed to detect eventual rickettsial or Borrelia bacteria being vectored by the ticks. For this purpose, hemolymph from all collected adult ticks was obtained as described by Burgdorfer (1970) and applied to microscope slides. Half of the samples were stained by Gimenez (1964) method and the other half using a Giemsa stain as described by Behmer et al. (1976), slightly modified. Modification consisted of using a distilled and tap water solution (1:1, approximate ph of 6.9), instead of alcohol for diluting the commercial Giemsa solution. Results In total 140 dogs were examined, 102 from urban areas and 38 from rural areas. Age of examined animals ranged from 3 months to 13 years. Fifteen different dog breeds were examined and most prevalent ones included mixed breed (66.4%), Teckel (5.7%), Poodle (5%), Boxer (4.3%), German shepherd (3.6%) and Brazilian Terrier (2.1%). Ticks were found on 27.5% of urban dogs and 36.8% of rural dogs. Detected infestation levels of dogs were as presented in Table 1. Apart from four Rhipicephalus nymphs from one urban dog, no other immature ticks were found in any animal, thus infestation levels presented above refer solely to adult ticks. A total of 179 adult ticks were identified. From these 159 (88.8%) were R. sanguineus, 11 (6.1%) A.ovale, eight (4.5%) Boophilus microplus and one (0.6%) A. cajennense. All ticks (100%) collected from urban dogs were R. sanguineus. Seven (50%) of infested rural dogs presented R. sanguineus ticks but A. cajennense was recovered from one (7.1%) dog, B. microplus from five (35.7%) dogs and A. ovale from three (21.4%) dogs. B. microplus infested dogs were from three different
912 Table 1. Tick infestation levels of urban and rural domestic dogs from Franca municipality and surroundings during 2000 and 2001 Score a Number of urban dogs Number of rural dogs 0 74 (72.5%) 24 (63.2%) + 21 (20.6%) 13 (34.2%) ++ 5 (4.9%) 1 (2.6%) +++ 2(2%) 0 a 0 (no tick found); + (1 10 ticks); ++ (11 100 ticks); +++ (>100 ticks). properties, all of which had dairy cattle. All dogs infested with A. ovale were from different properties. Mixed infestations included a dog infested with A. cajennense and A. ovale and another with B. microplus and R. sanguineus. Most of urban dog owners reported some kind of acaricidal treatment of their animals (71.6%), whereas only 18.4% of rural dog owners did so. Most of the urban dogs (66.7%) had access to streets or other non-domestic environment. Rural dogs shared their environment with horses, sheep, pigs and cattle. Wild mammals were seen in 15 of the properties (68.2%) harboring rural dogs. Wild mammals included deer species, giant anteaters, armadillos, monkeys, wildcats, maned wolf, capybara, wild dogs, and opossums. Some of the Giemsa and Gimenez stained hemolymph slides displayed bacteria but none of them resembled rickettsia or the highly characteristic spirochaete form of Borrelia. Discussion The present work is the first to gather information on ticks infesting dogs in Franca region in São Paulo state, Brazil. Data were collected for an overview of prevalent tick species in urban and rural areas. As such, data were collected from a large area but additional research will be needed to highlight some additional issues. For example, ticks from urban areas were collected during rabies vaccination campaign in the end of winter. Such an approach favored the collection of samples from all over the city to assess prevalence of tick infestation but information on seasonal distribution remains lacking. An unexpected result was the near absence of immature forms on the examined dogs both from urban and rural areas. It is possible that some larvae and nymphs may have been overlooked by the examination held on the street by the vaccination kiosks frequently on agitated, sometimes ferocious dogs. In rural properties, dogs are bred more freely and animals were, most of the time, unused to handling, which also hampered examination. But even
913 considering such working conditions, massive infestations of both larvae and nymphs would not have been missed and adult predominance throughout the collection period can be considered typical. In that case, it is possible that the short period of sampling was out of season for larvae and nymphs of R. sanguineus, the most prevalent tick. Unfortunately, there is no information about seasonal distribution for this tick species in Brazil. R. sanguineus was the most prevalent tick species in dogs from Franca region. In fact, it was the only species recovered from urban animals. Such a situation confirms this tick s capacity in developing in an urban area, and in kennels or other structures where dogs dwell (Walker et al., 2000). The prevalence of R. sanguineus in Franca urban region can be explained by several observations. First of all, dogs seem to lack ability to acquire an efficient immunity against this ectoparasite (Szabó et al., 1995). This tick species prefers the domestic dog as host for all stages of development (Walker et al., 2000). Although there is no information about seasonal distribution of R. sanguineus in Brazil, it is supposed that it can complete at least 2.5 generations per year in warm subhumid climate in Mexico (Cruz-Vazquez and Garcia Vazquez, 1999). Under laboratory conditions it can complete its life cycle in, approximately, 90 days (Bechara et al., 1995), which potentially permits four generations a year. Finally, dog dwellings seem to furnish ideal microenvironment for the development of all non-parasitic stages of the R. sanguineus as well as a good location for infestations of the host. The lack of non-r. sanguineus tick species in city, on the other hand, shows that other tick species from the region are unable to survive in such an environment and/or that dogs are not good hosts for these ticks. At the same time, the presence of Amblyomma species and of B. microplus on rural dogs is probably linked to a permissive environment and the sharing of habitat with other domestic and wild animals which act as primary hosts to these tick species. A. ovale is a common parasite on wild carnivores and rural dogs in Brazil (Aragão and Fonseca, 1961b; Massard et al., 1981; Barros-Battesti and Baggio, 1992). B. microplus is the main Brazilian cattle tick. European cattle (Bos taurus) and its cross breeds are the most affected hosts. Its presence on rural dogs may be explained by accidental parasitism coming from the coexistence of this host with dairy cattle on the farms, as happened in Franca. Should the dog be a permissive host for such tick species, high infestation levels would be expected on animals with access to highly infested pastures. Parasitisms of domestic dogs by B. microplus ticks under such conditions have already been described (Labruna et al., 2002). A. cajennense has a broad host range and is one of the most prevalent ticks in some wild environments in Brazil (Campos Pereira et al., 2000). On the other hand, it is important to note that adult forms exhibit some host specificity which is lower in the case of immature forms (Lopes et al., 1998). Although A. cajennense ticks have
914 been recovered from dogs quite frequently (Vianna and Bittencourt, 1995; Figueiredo et al., 1999; Campos Pereira et al., 2000; Labruna et al., 2000), its primary hosts are horses, tapirs, and capybaras (Labruna and Campos Pereira, 2001), animals which might develop massive infestations. This tick species is particularly important since it is the one that frequently attach to humans (Aragão and Fonseca, 1961a; de Lemos et al., 1997). Moreover A. cajennense is described as the main vector of the spotted fever agent, Rickettsia rickettsii, in Latin America (de Lemos et al., 1996; Figueiredo et al., 1999). Although more rural dogs were seen to carry ticks, these animals displayed lower infestation scores. Ticks from urban dogs were collected in the end of winter, while rural dogs were examined in the summer and so seasonal variation might be blamed for such a difference in infestation intensity. It is also possible that rural dogs, unrestricted in their movements throughout the farm and neighboring areas, dispersed engorged larvae, nymphs, and females and thus avoided high reinfestation rates of R. sanguineus. On the other hand, this higher movement range of dogs increased possibility of infestation with ticks dropped by other host species. Many of these ticks picked up by dogs in the farm or wild do not develop as they would in their natural host, thus leading to low infestation intensity. The examination of tick hemolymph did not reveal bacteria resembling Rickettsia or Borrelia. It is possible that the low sensitivity of the test could account for the negative results but it is also true that neither spotted fever nor lyme disease has been reported in the region. Moreover, hemolymph of only one from the main vector of Rickettsia in Brazil, A. cajennense, was examined. The vector for lyme disease in Brazil has not been determined (Fonseca et al., 1996). Babesia species were also not detected in the hemolymph of ticks. Although there is no reported statistics on tick-borne pathogens in Franca region, the Veterinary Hospital of the Franca University informed that overall prevalence of canine babesiosis is very low (Castro, M.B, personal communication). Another possible explanation for the lack of detection of babesia kinete stages in the hemolymph of ticks is that only healthy animals were sampled. There is an indication during the rabies campaign to vaccinate solely animals without disease signs. In conclusion, R. sanguineus is the main tick species in Franca region, although other tick species may be found feeding on dogs in rural areas. Since R. sanguineus is not considered as an important vector to humans (Walker et al., 2000), human tick-borne diseases are most prone to happen in rural areas of Franca where dogs and other domestic and wild animals harbor other tick species such as A. cajennense. At the same time vectoring of tick-borne diseases to dogs, especially erlichiosis, do happen in urban areas of Franca
915 (Castro, M.B, personal communication), attesting R. sanguineus importance as pathogen vector for this host species. Acknowledgements We thank Dr. Marcelo Bahia Labruna for confirming tick identifications, Dr. Alberto Guglielmone for critically reviewing this paper, Sanitary Vigilance Service of Franca for the permission to collect ticks during the rabies campaign, and to all dog owners who kindly let us collect ticks. References Aragão, H.B. and Fonseca, F. 1961a. Notas de Ixodologia. VIII. Lista e chave para os representantes da fauna ixodológica brasileira. Mem. Inst. Oswaldo Cruz 59(2): 115 130. Aragão, H.B. and Fonseca, F. 1961b. Notas de Ixodologia. IX. O complexo ovale do gênero Amblyomma. Mem. Inst. Oswaldo Cruz 59(2): 131 148. Barros-Battesti, D.M. and Baggio, D. 1992. Ectoparasites Ixodida Leach, 1817 on wild mammals in the state of Paraná, Brazil. Mem. Inst. Oswaldo Cruz 87(2): 291 296. Bechara, G.H., Szabó, M.P.J., Ferreira, B.R. and Garcia, M.V. 1995. Rhipicephalus sanguineus in Brazil: feeding and reproductive aspects under laboratorial conditions. Rev. Bras. Parasitol. Vet. 4(2): 61 66. Behmer, O.A., Tolosa, E.M.C. and Freitas, A.G.N. 1976. Manual de Técnicas Para Histologia Normal e Patológica. EDUSP, São Paulo. Burgdorfer, W. 1970. Hemolymph test. A technique for detection of Rickettsiae in ticks. Am. J. Trop. Med. Hyg. 19(6): 1010 1014. Campos Pereira, M., Szabó, M.P.J., Bechara, G.H., Matushima, E.R., Duarte, J.M.B., Rechav, Y., Fielden, L. and Keirans, J.E. 2000. Ticks on wild animals from the Pantanal region of Brazil. J. Med. Entomol. 37(6): 979 983. Cruz-Vazquez, C. and Garcia-Vazquez, Z. 1999. Seasonal distribution of Rhipicephalus sanguineus ticks (Acari: Ixodidae) on dogs in an urban area of Morelos, Mexico. Exp. Appl. Acarol. 23: 277 280. de Lemos, E.R.S., Machado, D.R., Coura, J.R., Guimarães, M.A.A. and Serra Freire, N.M. 1996. Infestation by ticks and detection of antibodies to spotted fever group Rickettsiae in wild animals captured in the State of São Paulo, Brazil. Mem. Inst. Oswaldo Cruz 91(6): 701 702. de Lemos, E.R.S., Machado, D.R., Pires, F.D.Á., Machado, S.L., da Costa, L.M.C. and Coura, J.R. 1997. Rickettsiae-infected ticks in an endemic area of spotted fever in the State of Minas Gerais, Brazil. Mem. Inst. Oswaldo Cruz 92(4): 477 481. Evans, D.E., Martins, J.R. and Guglielmone, A.A. 2000. A review of the ticks (Acari: Ixodida) of Brazil, their hosts and geographic distribution 1. The State of Rio Grande do Sul, Southern Brazil. Mem. Inst. Oswaldo Cruz 95(4): 453 470. Figueiredo, L.T.M., Badra, S.J., Pereira, L.E. and Szabó, M.P.J. 1999. Report on ticks collected in the southeast and midwest regions of Brazil: analyzing the potential transmission of tick-borne pathogens to man. Rev. Soc. Bras. Med. Trop. 32(6): 613 619.
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