ABSTRACT
Spotted fever illness caused by the tick-borne pathogen Rickettsia parkeri has emerged in the Pampa biome in southern Brazil, where the tick Amblyomma tigrinum is implicated as the main vector. Because domestic dogs are commonly parasitized by A. tigrinum, this canid is also a suitable sentinel for R. parkeri-associated spotted fever. Herein, we investigate rickettsial infection in ticks, domestic dogs and small mammals in a natural reserve of the Pampa biome in southern Brazil. The ticks A. tigrinum, Amblyomma aureolatum and Rhipicephalus sanguineus were collected from dogs. Molecular analyses of ticks did not detect R. parkeri; however, at least 34% (21/61) of the A. tigrinum ticks were infected by the non-pathogenic agent 'Candidatus Rickettsia andeanae'. Serological analyses revealed that only 14% and 3% of 36 dogs and 34 small mammals, respectively, were exposed to rickettsial antigens. These results indicate that the study area is not endemic for R. parkeri rickettsiosis. We tabulated 10 studies that reported rickettsial infection in A. tigrinum populations from South America. There was a strong negative correlation between the infection rates by R. parkeri and 'Candidatus R. andeanae' in A. tigrinum populations. We propose that high infection rates by 'Candidatus R. andeanae' might promote the exclusion of R. parkeri from A. tigrinum populations. The mechanisms for such exclusion are yet to be elucidated.
ABSTRACT
From June 2013 to January 2014, blood sera samples and ticks were collected from domestic dogs and wild small mammals, and ticks from the vegetation in a preservation area of the Atlantic Forest biome (Turvo State Park), and the rural area surrounding the Park in Derrubadas municipality, state of Rio Grande do Sul, southern Brazil. Dogs were infested by Amblyomma ovale and Amblyomma aureolatum adult ticks, whereas small mammals were infested by immature stages of A. ovale, Amblyomma yucumense, Amblyomma brasiliense, Ixodes loricatus, and adults of I. loricatus. Ticks collected on vegetation were A. brasiliense, A. ovale, A. yucumense, Amblyomma incisum, and Haemaphysalis juxtakochi. Three Rickettsia species were molecularly detected in ticks: Rickettsia bellii in I. loricatus (also isolated through cell culture inoculation), Rickettsia amblyommatis in A. brasiliense, and Rickettsia rhipicephali in A. yucumense. The latter two are tick-rickettsia associations reported for the first time. Seroreactivity to Rickettsia antigens were detected in 33.5% (55/164) small mammals and 8.3% (3/36) canine sera. The present study reveals a richness of ticks and associated-rickettsiae in the largest Atlantic Forest Reserve of the state of Rio Grande do Sul, which is characterized by a rich fauna of wild mammals, typical of more preserved areas of this biome. Noteworthy, none of the detected Rickettsia species have been associated to human or animal diseases. This result contrasts to other areas of this biome in Brazil, which are endemic for tick-borne spotted fever caused by Rickettsia rickettsii or Rickettsia parkeri.
Subject(s)
Ticks , Humans , Dogs , Animals , Brazil , MammalsABSTRACT
Background: broilers spend most of their lives in contact with litter; litter quality can affect their health and performance. Objective: the effects of litter treatment on performance and carcass lesions were evaluated in five consecutive flocks with 640 male broilers each. Methods: a completely randomized model was used comprising eight treatments and four replicates. The treatments included (1) untreated litter, (2) litter subjected to in-house composting, (3) litter treated (LT) with aluminum sulfate, (4) LT with gypsum, (5) LT with quicklime, (6) LT with dolomitic limestone, (7) LT with zeolite, and (8) LT with charcoal. Chopped elephant-grass hay was used as poultry litter in all flocks. Results: none of the litter treatments were found to influence the performance and carcass lesions of the male broilers in all five flocks. Furthermore, poultry litter treatments were not economically viable. Conclusion: poultry litter treatments did not affect the performance and scores of carcass lesions of male broilers, but increased the cost of poultry production.
Antecedentes: los pollos de engorde pasan la mayoría de su vida en contacto con la cama; la calidad de la cama puede afectar la salud y desempeño del ave. Objetivo: fueron evaluados los efectos de diferentes tratamientos de la cama sobre el desempeño y lesiones en la canal de pollos de engorde durante cinco lotes consecutivos con 640 aves cada uno. Métodos: se empleó un modelo completamente aleatorizado con ocho tratamientos y cuatro repeticiones. Los tratamientos incluyeron (1) cama no tratada, (2) cama sometida a compostaje en el galpón, (3) cama tratada (CT) con sulfato de aluminio, (4) CT con yeso agrícola, (5) CT con cal, (6) CT con calcáreo dolomítico, (7) CT con zeolita y (8) CT con carbón vegetal. Heno de pasto elefante picado fue usado como cama en todos los lotes. Resultado: los tratamientos no influenciaron el desempeño ni las lesiones en la canal de los pollos en ningún lote. Además, ninguno de los tratamientos de las camas fue económicamente viables. Conclusión: el tratamiento de la cama de pollo no solo no afecta el desempeño ni las lesiones en la canal de los pollos sino que eleva los costos de producción de las aves.
Antecedentes: os frangos de corte passam a maioria de suas vidas em contato com a cama e a qualidade desta pode afetar a saúde e o desempenho produtivo da ave. Objetivo: Avaliou-se os efeitos dos tratamentos da cama de frango sobre o desempenho no crescimento e lesões na carcaça de frangos de corte. Métodos: avaliaram-se 640 aves por lote, durante cinco lotes consecutivos, analisaram-se empregando um modelo completamente casualizado com oito tratamentos e quatro repetições. Os tratamentos consistiram de (1) cama não tratada, (2) cama submetida a compostagem no galpão, (3) cama tratada (CT) com sulfato de alumínio, (4) CT com gesso agrícola, (5) CT com cal virgem, (6) CT com calcário dolomítico, (7) CT com zeolita e (8) CT com carvão vegetal. Feno de capim elefante picado foi usado como cama em todos os lotes. Resultado: os diferentes tratamentos não influenciaram o desempenho na produção e as lesões na carcaça dos frangos em nenhum lote, entretanto, os tratamentos da cama foram economicamente inviáveis. Conclusão: o tratamento da cama de frango não afeta o desempenho produtivo e os escores de lesões na carcaça dos frangos de corte, além, eleva os custos da produção avícola.
