Kátia Maria Famadas

Molecular dissimilarities of Rhipicephalus sanguineus (Acari: Ixodidae) in Brazil and its relation with samples throughout the world: is there a geographical pattern?

In this study the genetic variability of Rhipicephalus sanguineus within Brazil and its relation with ticks of the same group from different continents was evaluated. Mitochondrial 12S and 16S rDNA fragments of R. sanguineus from seven Brazilian States were sequenced and compared to GenBank sequences of R. sanguineus and R. turanicus ticks from Africa, Asia, Europe, South America and USA. Results indicate a relatively high intra-specific variability between Brazilian samples but also a global latitude linked distribution pattern of at least two major R. sanguineus groups; one group distributed from latitude 25°N to 22°S including R. sanguineus from Brazil, Taiwan and Thailand and R. turanicus from Zambia and Zimbabwe, and the other group found closer to the poles, roughly above 29°N and below 30°S with ticks from Argentina, Uruguay, France, Oklahoma (USA), Israel and Egypt.

Amblyomma aureolatum and Ixodes auritulus (Acari: Ixodidae) on birds in southern Brazil, with notes on their ecology.

Between January 1999 and December 2000, 876 bird specimens were captured in three different ecological environments from the Reinhard Maack Park, Curitiba, State of Paraná, southern Brazil. A total of 142 birds (16.2%) were infested with Amblyomma aureolatum (Pallas 1772) (N = 699) and/or Ixodes auritulus Neumann, 1904 (N = 18) ticks. Questing A. aureolatum nymphs (N = 2) and adults (N = 5) were also collected from the soil and the vegetation. None of the I. auritulus were collected off-host. We collected only immatures of A. aureolatum on birds, but all life stages of I. auritulus. The latter species was collected on Turdus rufiventris and on Synallaxis ruficapilla, which is herein recognized as a host of I. auritulus for the first time. Moreover, this is also the first report of A. aureolatum infesting birds, and 16 different bird species were found infested. It was observed that larval infestation was positively correlated with the dry and cold season, while nymphal infestation was positively correlated with the warm and rainy season. Although only 2-years worth of data is provided, our results suggest the infestation of birds by ticks was significantly higher at the biotopes formed by forest at its first stage of regeneration ‘capoeira’ and the original Araucaria forest habitat ‘mata’ than the ecotone between forest and urban areas ‘peripheral area’.

Redescription of larva, nymph and adults of Ixodes (I.) loricatus Neumann, 1899 (Acari: Ixodidae) based on light and scanning electron microscopy

Ticks of the genus Ixodes are poorly known in the Neotropical zoogeographical region, from where only 45 species have been recorded. In Brazil, the genus is currently represented by eight species, four of which are known only from this country. This paper presents a redescription of all active stages in the life-cycle of I. loricatus, based on optical and scanning electron microscopy. In addition, the relationship of I. loricatus to other Neotropical Ixodes is presented and discussed.

Ornithodoros faccinii n. sp. (Acari: Ixodida: Argasidae) parasitizing the frog Thoropa miliaris (Amphibia: Anura: Cycloramphidae) in Brazil

BackgroundMost argasid ticks from the Neotropical region are parasites of mammals and birds, with a few records from reptiles. Many species of the genus Ornithodoros are known only through larval descriptions, and their chaetotaxy and morphological characteristics have been used to separate the taxa. In the present study, we describe the larva and the nymph of first instar of a new species of the genus Ornithodoros that was collected from frogs of the species Thoropa miliaris.MethodsLarvae of Ornithodoros were collected from frogs of the species T. miliaris at waterfalls in the state of Rio de Janeiro, southeastern Brazil. The larval and nymphal description was based on optical and scanning electron microscopy. Molecular analysis using the argasid 16S rRNA sequences available in GenBank was also conducted.ResultsOrnithodoros faccinii sp. n. is closely related to Ornithodoros clarki Jones & Clifford, Ornithodoros marinkellei Kohls, Clifford & Jones, Ornithodoros capensis Neumann and Ornithodoros sawaii Kitaoka & Susuki. However, the larval morphology of the new species is unique. The mitochondrial 16S rDNA partial sequence of O. faccinii generated in the present study was deposited in GenBank under the number KP861242.ConclusionsThe larvae collected from Thoropa miliaris are a new species, Ornithodoros faccinii n. sp. This is the first report of argasid ticks on frogs in Brazil, the second on frogs and the third on Amphibia in the Neotropical region.

Description of the larva of Amblyomma ovale Koch, 1844 (Acari: Ixodidae) by light and scanning electron microscopy

Abstract The larval stage of Amblyomma ovale Koch is described using optical and scanning electron microscopy. Unfed larvae were obtained from a colony of A. ovale originating from engorged females collected on domestic dogs from Monte Negro County, state of Rondônia, Western Amazon, Brazil. Fifteen larvae were prepared and mounted on slides, and observed under a light microscope equipped with a drawing tube. Five specimens were prepared for scanning electron microscopy. Several morphological characters are described for the first time, including the chaetotaxy of the idiosoma, palps and Hallers organ, as well as morphological features of the idiosoma, gnathosoma and legs. In addition, topographical and numerical patterns of integumentary pores (porotaxy) on the idiosoma of larval A. ovale are described using a recently proposed nomenclature. Three types of integumentary pores were identified on the idiosoma of A. ovale larvae: lyrifissures, small glands, and large wax glands. These structures were observed isolated or associated over the entire idiosoma, except on the scutum, which lacks large wax glands. Larvae of A. ovale showed similar topographical and numerical patterns of integumentary structures, with 6 pairs of large wax glands (1 pair dorsal/5 pairs ventral), 24 pairs of lyrifissures (11 pairs dorsal/13 pairs ventral), and 54 pairs of small glands (32 pairs dorsal/22 pairs ventral). These topographical and numerical patterns of integumentary structures of larval A. ovale showed only minor differences when compared with patterns of other Amblyomma larvae; however, a few key features can be used to differentiate A. ovale from other members of its genus.

Evidência de infecção por hantavírus em roedores silvestres capturados em uma área rural do estado de São Paulo, Brasil

Hantaviruses are the etiological agents of the Hantavirus Cardio-Pulmonary Syndrome, a serious rodent-borne disease in Brazil. In order to investigate the occurrence of hantavirus infection in wild rodents, a survey was conducted in three different suburban areas of the municipality of Pedreira, State of Sao Paulo, Brazil. Of the 145 wild animals captured belonging to 12 different species identified by morphology and karyological analysis, 107 were rodents of the following species: Akodon montensis, Bolomys lasiurus, Calomys tener, Oligoryzomys nigripes, Oligoryzomys flavescens, and Myocastor coypus. Blood samples from these rodents were assayed for the presence of antibodies against hantavirus by IgG ELISA using Andes recombinant nucleocapsid antigen. Antibody reactive to Andes virus was found in two different species, O. nigripes and O. flavescens. These results indicate a potential risk for hantavirus transmission to humans in this area, where reservoir rodents are present in peridomestic settings.

A note on slide-mounting technique of unfed immature stages of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae)

Several tick slide-mounting techniques have been used for many years with varying degrees of success. The classic Canada balsam technique employed by entomologists and acarologists over many decades is efficient but time consuming (RL Palma 1978 New Zeal Entomol 6 : 169-170). The classic methods used in Acarology include the water soluble media such as Berlese, Faure and Hoyer (GM Krantz 1978 A Manual of Acarology , Oregon State University Book Store, 2nd ed., Oregon, 509pp., A Fain 1980 Inter J Acarol 6: 169170). Water soluble media are inadequate in the humid tropic, even when the slides are ringed with a water-proofing material such as Glyptal. Crystallization of the media, probably due to absorption of water, is the main problem with slidemounting specimens. Basic procedures in slide-mounting techniques should involve death and fixing, clarifying and mounting of the arthropods in solutions that will produce minimal alterations of cuticle and its appendages. At some point of the procedure stains might be added to enhance visibility. The removal of gut contents is the main problem in ticks (even in unfed specimens). To do so an aqueous solution of potassium hydroxide has been used in different concentrations (10 to 20%). However, frequently the gut contents are not totally clarified and setae may break off. During the past four years we have mounted more than 100 unfed larvae and nymphs of Amblyomma cajennense (Fabricius, 1787) for morphological studies using the technique for copepods mentioned in WA Boerger and VE Thatcher (1990 Syst Parasitol 17: 133-141), with minor modifications as follows: 1. Unfed larvae and nymphs were obtained under laboratory conditions (25-29°C, 80 ± 10% RH) and kept alive until hardening of the cuticle (15 days for larvae and 24 hr for nymphs). The ticks were killed in either hot water or 70% ethanol (approximately 70°C) and, then preserved in 70% ethanol. 2. Fixed specimens were subsequently transported to lactic acid for 1 hr at 50°C. 3. Specimens were further transferred to an alcoholic solution saturated with phenol. The specimens should be left in phenol solution (approximately 24 hr). After clarification had been finished, specimens were washed in 100% ethanol. 4. Washed specimens were transferred to a solution of pure creosote for approximately 24 hr and then mounted in Canada balsam medium.

Streblidae (Diptera) on bats (Chiroptera) in an area of Atlantic Forest, state of Rio de Janeiro

Because of the few records of Streblidae on bats, despite extensive study on these mammals in the state of Rio de Janeiro, a survey was carried out in an area of Atlantic Forest, in the municipality of Nova Iguaçu, known as the Tinguá region. Thirteen species were added to the list of Streblidae in the state of Rio de Janeiro, of which two were new records for Brazil. Thirty-one species have now been reported this state.

Topographical and numerical study of the idiosomal integumentary structures of the larva of four Neotropical species of Amblyomma Koch, 1844 (Acari: Ixodidae).

Integumentary structures of the larvae of Amblyomma longirostre (Koch, 1844), A. parvum Aragão, 1908, A. rotundatum Koch, 1844 and from three populations of A. cajennense (Fabricius, 1787) were studied using light microscopy. A new nomenclature for the localisation of the integumentary structures is proposed. Three types of integumentary structures were identified in the larval idiosoma of the four Amblyomma species: lyrifissures, small glands and large wax glands. These structures were observed isolated or associated over the entire idiosoma, except in the scutum, which lacked lyrifisures and large wax glands. Large wax glands were the most stable within and between the tick species, followed by lyrifissures and small glands. Small glands, although relatively stable, showed the highest number of numerical variations within and between the tick species. Even though there were intra-population variations in the topographical and numerical pattern of some integumentary structures of A. cajennense larvae, there was a definitive pattern for most of the specimens, as showed by the similar modal and mean numbers of integumentary structures per tick side. The patterns of lyrifissures, small glands and large wax glands showed little differences when compared between the four Amblyomma species; however, a few differences were well evident. These differences were sufficient to differentiate larvae of the four species. Thus, we expect that the study of integumentary structures on the larvae of other Amblyomma species will be useful in future taxonomic keys for the identification of Amblyomma larvae from the Neotropical region.

Composition of bat assemblages (Mammalia: Chiroptera) in tropical riparian forests

Various studies have focused on the richness and abundance of bats in tropical forests and how the composition of these forests affects bat assemblages, but there are few studies on the relationship of bats with riparian forests. The aim of this study was to ascertain the differences among bat assemblages of three riparian forest areas of the Tingua region, state of Rio de Janeiro, Brazil. These areas were: I) an agricultural area (Takume); II) a reforested area in primary succession (Canavarro); and III) an area with late secondary vegetation (Tingua Biological Reserve). Assessments of bat species composition in these areas may shed light on how anthropogenic modifications in riparian forests can influence local bat assemblages. Bats were captured with mist nets during 72 sampling nights. Total bat abundance was 1,511 individuals in 26 species. The three areas differed in their species composition. The Tingua Biological Reserve was the richest area, Canavarro presented the lowest diversity and the highest abundance of individuals, and the evenness index was highest in Takume. The differences found in the composition and ecological indices indicate that bat assemblages have distinct characteristics in the three areas studied, with varied degrees of transformation and anthropization.