Abstract Ticks represent a large group of pathogen vectors that blood feed on a diversity of hosts. In the Americas, the Ixodidae ticks Amblyomma cajennense are responsible for severe impact on livestock and public health. In the present work, we present the isolation and molecular identification of a group of culturable bacteria associated with A. cajennense eggs from females sampled in distinct geographical sites in southeastern Brazil. Additional comparative analysis of the culturable bacteria from Anocentor nitens, Rhipicephalus sanguineus and Ixodes scapularis tick eggs were also performed. 16S rRNA gene sequence analyses identified 17 different bacterial types identified as Serratia marcescens, Stenotrophomonas maltophilia, Pseudomonas fluorescens, Enterobacter spp., Micrococcus luteus, Ochrobactrum anthropi, Bacillus cereus and Staphylococcus spp., distributed in 12 phylogroups. Staphylococcus spp., especially S. sciuri, was the most prevalent bacteria associated with A. cajennense eggs, occurring in 65% of the samples and also frequently observed infecting A. nitens eggs. S. maltophilia, S. marcescens and B. cereus occurred infecting eggs derived from specific sampling sites, but in all cases rising almost as pure cultures from infected A. cajennense eggs. The potential role of these bacterial associations is discussed and they possibly represent new targets for biological control strategies of ticks and tick borne diseases.

As Rocky Mountain Spotted Fever is the most common tick-borne disease in South America, the presence of Rickettsia sp. in Amblyomma ticks is a possible indication of its endemicity in certain geographic regions. In the present work, bacterial DNA sequences related to Rickettsia amblyommii genes in A. dubitatum ticks, collected in the Brazilian state of Mato Grosso, were discovered. Simultaneously, Paracoccus sp. was detected in aproximately 77% of A. cajennense specimens collected in Rio de Janeiro, Brazil. This is the first report of Paracoccus sp. infection in a specific tick population, and raises the possibility of these bacteria being maintained and/or transmitted by ticks. Whether Paracoccus sp. represents another group of pathogenic Rhodobacteraceae or simply plays a role in A. cajennense physiology, is unknown. The data also demonstrate that the rickettsial 16S rRNA specific primers used forRickettsia spp. screening can also detect Paracoccus alpha-proteobacteria infection in biological samples. Hence, a PCRRFLP strategy is presented to distinguish between these two groups of bacteria.

Experimentamos o novo inseticida bendiocarb para o combate ao Panstrongylus megistus, principal vetor da doença de Chagas, em uma área endêmica do Estado da Bahia, Brasil. Uma das partes da experiência constou da aplicação de 0,4 g/m² de bendiocarb a 80% pelas equipes de guardas borrifadores oficiais. A taxa de infestação das casas foi reduzida de 18% para 7%, seis meses após a aplicação do inseticida, e a densidade de P. megistus caiu de 7 para 1,5 exemplares por hora. A outra parte constou da utilização da mão-de-obra dos habitantes na inspeção de suas casas para triatomíneos, da aplicação por meio de uma pequena bomba manual, de bendiocarb a 20%, sempre que observassem triatomíneos. A taxa de infestação das casas foi reduzida de 48% para 14% e a densidade de P. megistus caiu de 12 para menos de 1 exemplar por hora. Apesar da concentração mais fraca, o bendiocarb aplicado com a colaboração da população, apresentou resultados mais eficientes, provavelmente devido à constante vigilância com que ficou a área, havendo conseqüentemente, maior freqüência na aplicação do inseticida. O método de combate aos vetores com a participação da população mostrou-se mais eficiente e menos dispendioso. Dessa forma, se adotado pelos serviços de combate às endemias no Brasil, talvez venha a ser a solução para a descontinuidade das campanhas contra a doença de Chagas.

Bendiocarb was evaluated as a control agent for Panstrongylus megistus, an important vector of Chagas' disease in Bahia State, North-East Brazil. The field work consisted of two parts. In one, Ficam W(80% bendiocarb) at 0.4g a. i./m² was applied by experienced spray operators; house infestation rates were reduced from 18% prespray to 7% postspray (6 months after the final bendiocarb application), and P. megistus densities decreased from 7per man/hour to 1.5 per man/hour. In the other part of the trial, 27 householders were supplied with a small hand sprayer and Ficam 20 (20% bendiocarb) in premeasured waterproof sachets. They were instructed to spray every 3 months orwhenevertheysawbugs. Both householder compliance and acceptability, because of the lack of odour of the insectice, were good. The result was a decrease in the rate of infested houses from 48% to 14% and in P. megistus density from 12 per man/hour to less than 1 per man/hour. This indicated a possibly better level of control by householders applying insecticide every 3 months, than by spraymen every 6 months. In both trials, no adverse effects of spraying on householders were noted. The community participation approach represents a new method for the control of the vectors of Chagas'disease. It is likely to be much less expensive than conventional systems and would integrate very well in a primary health care programe.

Foram comparados quatro métodos para detectar a infestação dos domicílios por triatomíneos: 1) coleta manual; 2) coleta manual após a aplicação depiretro; 3)procura de ovos viáveis; e 4) caixas de Gomez-Nuñez. A coleta manual foi o método mais sensível (23% de infestação), seguido da aplicação de piretro (21%), das caixas de Gomez-Nuñez (15%) e finalmente dos ovos viáveis (12%). Cerca de 10% das casas infestadas foram exclusivamente positivas no teste das caixas de Gomez-Nuñez. Ainda mais, 6 das 7 casas positivas exclusivamente pelo método de Gomez-Nuñez estavam localizadas numa área recentemente borrifada, onde a densidade de Pans-trongylus megistus era muito baixa. A inspeção das caixas de Gomez-Nuñez 12 semanas após a aplicação de inseticida foi duas vezes mais efetiva do que a inspeção 6 semanas após a aplicação de inseticida. As manchas de fezes eram as evidências mais comuns para indicar a presença de P. megistus dentro da caixa de Gomez-Nuñez. A caixa de Gomez-Nuñez é um complemento útil da coleta manual para detectar a infestação domiciliar pelo P. megistus, especialmente nas áreas onde a densidade de triatomíneos é baixa. Contudo, a utilidade das caixas de Gomez- Nunez deve ser levada em consideração com re-ferência ao tempo e trabalho que requerem.

Four methods for detecting household infestations with Panstrongylus megistus were compared: 1) manual collection; 2) collection after pyrethrum application; 3) search viable eggs; and 4) Gomez-Nuñez boxes. Manual collection was the most sensitive method (23% infested), followed by pyrethrum (21%), Gomez-Nuñez boxes (15%) and viable eggs (12%). About 10% of infested houses were positive exclusively on the Gomez-Nuñez box test. More over, 6 out of the 7 houses positive exclusively on the Gomez-Nuñez method were located in a recently sprayed area, where P. megistus density was low. Inspection of Gomez-Nuñez boxes at 12 weekspost-application was twice as effective as inspection at 6 weekspost-application. Triatomine feces was the most common evidencefor thepresence of P. megistus found within Gomez-Nuñez boxes. Gomez-Nuñez boxes area a useful adjunct to manual collection in detecting domestic infestations with P. megistus, especially in areas where bug densities are low. However, the utility of Gomez-Nuhez boxes must be weighed against the time and labor they require.