ABSTRACT
An artificial feeding system was used where citrated bovine blood was offered to male and female Amblyomma cajennense. Vestiges of blood, sweat, hair and exfoliated skin were used as phago-stimulants placed on the surface of the silicone membrane. The ticks were collected, as engorged nymphs, from naturally infested equines, with the ecdysis occurring in the laboratory. Four hundred ticks were used, 50% being female, at three to four weeks post-ecdysis. Vestiges of blood on the silicone membrane were the most efficient phago-stimulant and the association of vestiges of blood and sweat residue smears yielded better results compared to the other phago-stimulants used.
Subject(s)
Entomology/methods , Ticks/physiology , Animals , Female , Male , SiliconesABSTRACT
Rhodnius pictipes (Hemiptera, Reduviidae) from Serra Norte, State of Pará, Brazil, acclimatized in an insectary at the Laboratório Nacional e Internacional de Referência em Taxonomia de Triatomíneos, Departamento de Entomologia, Instituto Oswaldo Cruz, were fed through a silicone membrane. In order to know the viability and the efficiency of this membrane compared with insects fed on mice, the number of bloodmeals taken, period of development of the five nymphal instars, longevity of adults, average amount of blood intake in each meal and percent of mortality were observed. A total of 310 insects, were used, comprising 50 nymphs of each instar, as well as 30 male and 30 female adults. Insects fed artificially had reduced minimal and maximal periods of development than the group fed on mice. The largest relative increase of body weight was observed in the 2nd instar followed by the 1st, and the amount of blood ingested increased during the development, to the 5th instar for both groups. There were no significant differences between the groups fed artificially and in vivo according to Tukey's test for p > 0.05. The percent of mortality in the 1st instar was 18% for artificially fed and 16% for the group fed on mice; these percentages decreased as insects developed until the 4th instar, without mortality, returning to increase in the 5th instar. R. pictipes was shown to be easily adaptable to artificial feeding, and could be considered as an important and viable experimental model.
Subject(s)
Entomology/methods , Rhodnius/growth & development , Animals , Chagas Disease/transmission , Female , Male , Mice , SiliconesABSTRACT
Since 1989, we have identified 25 patients with Lyme disease, 15 in early and 10 in latent stage, supporting its existence in Brazil, according to following reasons: 1) presence of clinical manifestations compatible with Lyme disease, with cutaneous, articular, nervous system and rarely cardiac envolvement; 2) presence of antibodies against Borrelia burgdorferi; 3) follow up of acute cases show sorologycal changes; 4) good antibiotic response at early stage of disease and only satisfactory in latent form; 5) mapping of risk areas, according to geographycal distribution of patients; 6) presence and identification of Ixodid ticks; 7) identification of micro-organism like borrelias in human, wild animals and ticks cultures, seen by dark field microscope; 8) sorology done in dogs and oxes, confirm existence of risk areas for Lyme disease.
Subject(s)
Insect Vectors , Lyme Disease/epidemiology , Ticks/microbiology , Adult , Animals , Borrelia burgdorferi Group/isolation & purification , Brazil/epidemiology , Child , Child, Preschool , Female , Humans , Lyme Disease/complications , Lyme Disease/diagnosis , Lyme Disease/drug therapy , Male , Middle AgedABSTRACT
Current methods for the control of the cattle tick Boophilus microplus infestations are not effective and the parasite remains a serious problem for the cattle industry in tropical and sub-tropical areas. Recent advances have introduced the possibility for the immunological control of the parasite through the use of recombinant vaccines. Recently, it was shown that the recombinant vaccine Gavac (Heber Biotec S.A.) is able to control B. microplus populations in artificially infected grazing dairy cattle in Cuba. To assay the effect of the vaccine on a different B. microplus strain and under different ecological conditions, we conducted a trial in Brazil on grazing dairy and beef pure and cross-bred cattle under natural infestation conditions. A farm in the northeast of the state of Sao Paulo was selected and two groups of animals per breed were included in the experiment and were maintained grazing on separate but similar pastures. For each breed, one group was vaccinated with the vaccine Gavac and the second group was not vaccinated and was employed as a control. In vaccinated cattle, during 36 weeks of experiment, the average infestation rate was maintained below 78 ticks per animal while average infestation peaks (mean +/- S.E.) of 144 +/- 44 ticks per animal (for dairy cross-bred cattle) and 195 +/- 42 ticks per animal (for beef cross-bred cattle) were recorded in the control groups. Tick infestation rates showed statistical significant differences (p = 0.04) between both experimental groups throughout the experiment. These results clearly showed, as in the Cuban study, that the vaccine controlled tick numbers in successive generations in the field.
