Culicídeos associados a bovinos de leite, no sul do Rio Grande do Sul, Brasil / Mosquitoes associated with dairy cattle in southern Rio Grande do Sul, Brazil

The occurrence of mosquitoes in the authoring environment of dairy cattle was verified in southern Rio Grande do Sul. For collection of specimens, it was installed a Magoon trap, in which during a couple of cattle-approximately six months of age was placed. Samples were collected during 24 hours, twice a month for 12 months. After 24 hours, the cattle were removed from the trap and the insects were collected inside the trap, with the aid of glass bottles, containing, cotton soaked in acetone. The specimens were taken to the Laboratory of Insect Biology, at the Universidade Federal de Pelotas, to sorting, counting, sexing and identification. Of the mosquitoes caught, specimens of Culex sp. Ochlerolatus scapularis and Mansonia titillans were present. Culex sp. had the largest number of individuals (39).

Desenvolvimento de Periplaneta australasiae Fabricius (Blattodea, Blattidae) em temperatura constante de 30º c e em temperatura ambiente de laboratório / Development of Periplaneta australasiae Fabricius (Blattodea, Blattidae) at a constant temperature of 30° c and at ambient laboratory temperature

Objetivou-se avaliar o desenvolvimento de ovos e ninfas de Periplaneta australasiae (Fabricius) à temperatura de 30 ± 0,2° C, umidade relativa 80 ± 15% e fotofase de 12h e em condições ambientais de laboratório, sem controle de temperatura e umidade relativa; visando à subsídios para medidas de prevenção e controle. As ootecas foram individualizadas em tubos de ensaio até a eclosão. As ninfas foram transferidas para cubas de vidro e alimentadas com ração comercial para coelhos e água ad libitum até a emergência das imagos. Avaliou-se, período de incubação, número de ovos/ ooteca, viabilidade de ovos, número de ninfas/ooteca, período ninfal, viabilidade de ninfas e período ovo/adulto. A diferença do período médio de incubação à temperatura de 30° C (38 dias) e no ambiente (44,5 dias) foi significativa (p < 0,0001); eclodiram, em média 18,1 ninfas/ooteca a 30° C e 21 ninfas/ooteca em condições ambientais (p = 0,006); o período médio de ninfa a 30° C foi de 155,9 dias e no ambiente 279,7 dias (p < 0,0001); a viabilidade de ninfas foi superior a 50%, tanto a 30° C (55,1%) quanto em condições de laboratório (57,2%); no período médio de ovo-adulto de P. australasiae, houve diferença significativa (p< 0,001) entre a temperatura de 30 °C (194,1 dias) e em condições ambientais de laboratório (337,3 dias). Em condições de laboratório, os períodos de incubação, de ninfa e de ovo-adulto de P. australasiae foram aumentados em relação à temperatura de 30° C, não ocorrendo, entretanto, perda nem redução de viabilidade em nenhuma das fases.

With the objective of obtaining standards of measurement for prevention and control, this study compared the development of the eggs and nymphs of Periplaneta australasiae (Fabricius) at a temperature of 30 ± 0.2° C, relative humidity 80 ± 15% and photoperiod of 12 hours versus ambient conditions in the laboratory without controls of temperature and RH. Single ootheca were maintained in test tubes until ecolosion, and nymphs were transferred to glass cubes and fed commercial rabbit ration and water ad libitum until emergence of the imagos. The incubation period, number of eggs/ ootheca, viability of the eggs, number of nymphs/ootheca, nymphal duration, viability of nymphs and duration of egg to adult were all evaluated. The mean difference in the incubation period between the temperature of 30° C (38 days) and ambient conditions (44.5 days) was significant (p < 0.0001); a mean of 18.1 nymphs/ootheca ecloded at 30° C, while 21 nymphs/ootheca ecloded under ambient conditions (p = 0.006); the mean nymphal period at 30° C was 155.9 days while for the ambient it was 279.7 days (p < 0.0001); nymphal viability was greater than 50% for both the 30° C laboratory (55.1%) and the ambient (57.2%); and the mean period from egg to adult of P. australasiae was significantly different (p < 0.001) between the 30° C temperature (194.1 days) and the ambient conditions of the laboratory (337.3 days). Under ambient conditions, the duration of nymphal incubation and egg to adult development of P. australasiae were increased relative to the temperature of 30° C without a reduction in viability in any of the stages.

Anti-Trypanosoma cruzi antibody detection in blood donors in the Southern Brazil

Trypanosoma cruzi, the causal agent of Chagas' Disease, is a widely spread protozoa in America. Blood transfusion is the secondly most important way of acquiring the infection. In blood banks, tests are performed to eliminate potentially infected blood. This study aimed to evaluate the positivity for T. cruzi in blood samples of donor's candidates in Southern Brazil. The study was based on a sampling containing all blood donors of Hemopel - a Pelotas City Blood Center, Rio Grande do Sul State, Brazil, from 2004 to 2005. Serological study was performed using ELISA Chagatest. Sampling containing values ± 20 percent cut off were evaluated using ELISA Chagatek, ELISA Alka/Adaltis, IHA Chagatest and IIF Imunocruzi. TESA-Blot was used as a confirmatory procedure in situations where blood samples showed conflicting results. From 4,482 samples collected in 2004 and 2005, the reactivity for anti-T. cruzi was 0.96 percent (43). Among those, 21 cases (0.47 percent) were confirmed as positive - most of them were female, with low school level and averaging 47.2 percent years old. Interestingly, the blood donors are not aware of being contaminated and this fact makes it difficult for controlling the disease. Chagas' Disease was one of the main reasons for discarding blood bags through serological control in Southern Brazil. Sampling reactivity showed variation among the different techniques used for anti-T. cruzi research. In order to obtaining more secure and conclusive results, more than one diagnostic technique must be used.