Environmentally Safe Photodynamic Control of Aedes aegypti Using Sunlight-Activated Synthetic Curcumin: Photodegradation, Aquatic Ecotoxicity, and Field Trial.

This study reports curcumin as an efficient photolarvicide against Aedes aegypti larvae under natural light illumination. Larval mortality and pupal formation were monitored daily for 21 days under simulated field conditions. In a sucrose-containing formulation, a lethal time 50 (LT50) of 3 days was found using curcumin at 4.6 mg L-1. This formulation promoted no larval toxicity in the absence of illumination, and sucrose alone did not induce larval phototoxicity. The photodegradation byproducts (intermediates) of curcumin were determined and the photodegradation mechanisms proposed. Intermediates with m/z 194, 278, and 370 were found and characterized using LC-MS. The ecotoxicity of the byproducts on non-target organisms (Daphnia, fish, and green algae) indicates that the intermediates do not exhibit any destructive potential for aquatic organisms. The results of photodegradation and ecotoxicity suggest that curcumin is environmentally safe for non-target organisms and, therefore, can be considered for population control of Ae. aegypti.

[Occurrence of antibodies and risk factors for infection for Toxoplasma gondii in dogs in the cities of Lages and Balneário Camboriú, Santa Catarina State, Brazil]. / Ocorrência de anticorpos e fatores de risco para infecção por Toxoplasma gondii em cães, nas cidades de Lages e Balneário Camboriú, Santa Catarina, Brasil.

The aim of this study was to identify the occurrence of antibodies and risk factors for infection for Toxoplasma gondii in dogs in the cities of Lages and Balneário Camboriú, Santa Catarina State, Brazil. Blood samples from 400 domiciliated dogs were processed for antibody detection against T. gondii by indirect immunofuorescence antibody test (IFAT). The following variables were obtained by questionnaire: breed, age, sex, diet, environment, presence of cats and street access. A Chi-Square test was performed to verify the association between the seroprevalence with the studied variables. From all evaluated dogs, 89 (22.3%) had antibodies against T. gondii. A total of 52 (26%) and 37 (18.5%) dogs were positive for T. gondii in Lages and Balneário Camboriú, respectively. No statistical differences were observed on the prevalences of T. gondii between both cities. Greater occurrences of seropositives for toxoplasmosis were observed in mixed-breed dogs (P = 0.002), who had access to the street (P = 0.003) and received homemade diet (P = 0.028). A strong trend for seropositivity against T. gondii was observed among adult dogs, indicating post-natal exposure, and among those that have previous contact with cats.

[Amblyomma tigrinum in the Municipality of Lages, SC, and biology observations under laboratory conditions]. / Amblyomma tigrinum no Município de Lages, SC e observações da biologia em condições de laboratório.

To study the biological features of Amblyomma tigrinum, samples of engorged females collected from dogs in the city of Lages, SC, Brazil, were maintained in Petri dishes into an incubator at 27+/-1 degrees C and 80+/-10% RH, for egg laying. For the development of the subsequent experimental phases, artificial infestations were performed in rabbits using the technique of the cotton bag glued to the ear's base. The mean period of hatch, feeding and larval molt were 11.67, 5.93 and 10.96 days, respectively, whereas the mean period of feeding and nymph's molt were 12.40 and 16.27 days, respectively. Only one engorged female was obtained, with detachment observed on the 22(nd) day. The longevity periods for larvae, nymphs and adults were 75, 96 and 150 days respectively.

[Larvae culture of ovine gastrintestinal nematodes in sawdust substrates of Pinus taeda, P. elliottii and Araucaria angustifolia]. / Cultivo de larvas de nematóides gastrintestinais de ovinos em substratos de serragem de Pinus taeda, P. elliottii e Araucaria angustifolia.

The aim of this study was to verify the influence of sawdust substrates obtained from wood treated with sodium tribromophenate and not treated of Pinus elliotti, P. taeda, and Araucaria angustifolia in larval cultures of ovine gastrintestinal helminths. Feces samples were collected between 8 to 12am, from a lamb naturally infected with gastrintestinal nematodes and analysed by the modified Mc Master technique for worm egg counting (epg). Six groups of 20g of feces were prepared. Each group received 5g of one of the sawdust substrates and 5ml of distilled water. The material has been processed, identified and taken to a climatized chamber with a temperature of 27 +/- 1 degrees C, relative humidity above 70%, and in escotophase for seven days. The third stage larvae were recovered by the Baermann technique after four hours of sedimentation for the counting and identification of one hundred larvae per treatment. For each treatment were realized 10 repetitions. The average of EPG of Strongylida Order was 630. The average of the larvae number obtained in 20 grams of feces and the percentage of recovery in the different substrates based on the EPG was: P. taeda treated, 2719 (22.66%) and not treated, 2353 (20.08%); P. elliotti treated, 3069 (22.48%) and not treated, 3181 (24.54%); A. angustifolia treated, 2370 (18.73%) and not treated, 3361 (26.75%). There was no statistic difference in 5% level of significance between the averages and the number of larvae in the different substrates.

[Seasonal variation of Haematobia irritans in the Santa Catarina State plateau and eficiency of the "Directed Control"]. / Variação sazonal de Haematobia irritans no planalto catarinense e eficiência do "Controle Dirigido".

This experiment had the aims of collecting information about seasonal variation; to evaluate the efficacy of the directed control method, in which only the most susceptible animals to Haematobia irritans infestations are treated and to reduce treatment costs. From February 2001 to April 2003, in two farms situated in Lages, Santa Catarina State, Brazil, two groups of 17 adult animals each (one group per farm) were used to count fly infestation every 14 days. In farm I, 29.4% of the animals were treated with pour-on cypermethrin, at 5 mg/kg live weight, when infestations reached an average above 200 flies (Directed Control). In farm II, treatments were used according to the farmer's decision. Evaluations of the efficacy of treatments were performed 1 to 7 days after treatment. The heaviest infestations occurred from November to April, and the number of flies did not surpassed 115.25 in average. Animals in farm I were treated only once, in December 2001, and a reduction of the infestation of H. irritans of 89.35% was showed. The 29.4% of most susceptible animals, in the time of heaviest infestations, sustained 65.97% of the total population of H. irritans. In farm II, animals were treated 9 times, and the efficacy of the treatments reached 98.25%. It was found that in this farm an excessive number of treatments have been used for the control of H. irritans.