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| Author(s): |
Maria Halina Ogrzewalska
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2009-08-28 |
| Examining board members: |
Fernando Ferreira;
Darci Moraes Barros Battesti;
Ricardo Augusto Dias;
Marcelo Bahia Labruna;
Matias Pablo Juan Szabo
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| Advisor: | Fernando Ferreira |
| Field of knowledge: | Agronomical Sciences - Veterinary Medicine |
| Indexed in: | Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP |
| Location: | Universidade de São Paulo. Biblioteca da Faculdade de Medicina Veterinária e Zootecnia; T.2148 FMVZ |
| Abstract | |
Habitat fragmentation causes reduction in species diversity, affecting the relationships between vertebrate hosts and parasites. We tested if patch size has influence on forest birds diversity, which could affect the prevalence of ticks on wild birds. During two years we conducted a bird survey, using mist net in 12 areas: four small patches (80-140 ha), four large ones (480-1850 ha) and four control areas within the Morro do Diabo State Park (~36000 ha). Free living ticks were also collected through dragging the vegetation. Identified ticks were tested in the laboratory for the presence of Rickettsia. A total of 1,745 birds were captured representing 80 species from 24 families. A total of 223 (13%) birds were found infested by immature forms of ticks: 1,800 larvae and 539 nymphs. The most common tick parazitizing birds was Amblyomma nodosum. Other species, Amblyomma coelebs, Amblyomma cajennense, Amblyomma ovale, Amblyomma longirostre, Amblyomma calcaratum, and Amblyomma naponense were found sporadically. Among free-living ticks collected in the environment, A. cajennense was the most common followed by A. coelebs, A. naponense, Amblyomma brasilense and Haemaphysalis juxtakochi. From two individuals of A. nodosum ticks, rickettsiae were isolated in Vero cell culture and the isolates were molecularly characterized using the rickettsial genes gltA, htrA, and when possible also ompA and ompB. The first isolate was identified as Rickettsia bellii and the second isolate, was identified as R. parkeri. Among 174 A. nodosum tested, 41 (23.6%) were found to be infected by R. parkeri and 10 (5.7%) were infected with R. bellii strain Pontal. Bird diversity was higher in control and large areas, but various species of birds and also ticks responded in different way for fragmentation. A. nodosum parasitizing birds was more abundant in small patches, while A. cajennense found on birds and in the environment was more abundant in control and large areas. These differences of the occurrence of ticks could be related with the abundance of main vertebrate hosts, or environmental conditions such as temperature and humidity in sampled areas. This is a result of fragmentation of habitat and shows the lack of balance between the environment-host-parasite relationships. (AU) | |