Gervásio Henrique Bechara

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In this work, the biology, mitochondrial DNA and fertility of hybrids from two strains of Rhipicephalus sanguineus, from Brazil and Argentina, were compared. Engorged larvae, nymphs and adults from Argentina weighed more and the engorgement period of adult females was significantly longer than those of their Brazilian counterparts, whereas adult female tick(More)
This paper describes the identification of ticks from wild animals of the Pantanal region in Brazil as part of a comprehensive study about established and emerging tick-host relationships and related pathological aspects. Eighty-one animals were captured (representing 13 species, six orders), and ticks were found on 63 (78%). Tick species identified(More)
The tick Rhipicephalus sanguineus is a very common parasite of dogs worldwide. Dogs seem unable to acquire resistance against this tick species, whereas guinea pigs demonstrate a very strong resistance following primary infestation. We studied the inflammatory reaction at the R. sanguineus tick feeding site on dogs and guinea pigs during primary and(More)
Many studies have been conducted with plants whose extracts have the potential to be used for pest control. One of these plants is Azadirachta indica (neem), whose main active ingredient is azadirachtin, a compound shown to have acaricide and insecticide activity. Rhipicephalus sanguineus (brown dog tick) is currently considered to be an "urban pest,"(More)
Heme is present in all cells, acting as a cofactor in essential metabolic pathways such as respiration and photosynthesis. Moreover, both heme and its degradation products, CO, iron and biliverdin, have been ascribed important signaling roles. However, limited knowledge is available on the intracellular pathways involved in the flux of heme between(More)
The cutaneous hypersensitivity induced by Rhipicephalus sanguineus tick extract in dogs (natural host) and guinea-pigs (laboratory host) was evaluated. The left ear of infested and control (tick-bite naive) dogs and guinea-pigs was injected intradermally with an extract from unfed adult ticks and the right ear with phosphate buffered saline (PBS). Ear(More)
The acquisition of resistance in goats against Amblyomma cajennense after repeated infestations and the role of inflammatory cells in this mechanism were investigated. Ten naive goats aged 6 months were distributed into two groups: test (n= 5), infested thrice at 30-day intervals; and control (n= 5), infested once. Nymphs (n= 115 per animal per infestation)(More)
In this work we describe the internal morphology of the female reproductive system of the cayenne tick Amblyomma cajennense. This system is represented by a panoistic ovary, which lacks nurse cells in the germarium. This ovary consists of a single tube, in which a large number of oocytes develop asynchronously, thus accompanying the processes of yolk(More)
This study describes the ovary anatomy and dynamics of oocytes maturation process of Amblyomma brasiliense ticks. The ovary is of panoistic type lacking nurse and follicular cells. This organ consists of a single continuous tubular structure comprising a lumen delimited by the ovarian wall. Oocytes of this tick species are classified into five stages (I-V)(More)
Inhibited permeability responses to intradermally injected histamine, serotonin and bradykinin were observed in leucopenic rats, when compared to those measured in normal animals. Significant reversal of the inhibited responses was seen when leucopenic rats were given suspensions of lymphocytes i.v. Suspensions of PMN granulocytes, however, were(More)