ABSTRACT
A field survey of resistance was conducted based on the larval packet test technique with synthetic pyrethroids (cypermethrin and deltamethrin) and organophosphates (chlorpyriphos) in Rhipicephalus (Boophilus) microplus field populations from six different regions of the State of São Paulo (Brazil). 82.6% of the populations showed resistance to cypermethrin, 86.36% to deltamethrin and 65.25% to chlorpyriphos, with 50% presenting resistance to both SP and OP acaricide. According to the questionnaires completed by the producers, OP+SP mixtures followed by SP-only formulations were the products most commonly used for controlling the cattle tick in the surveyed areas. The present study showed high occurrence of resistance to SP and OP in the State of São Paulo, Brazil and revealed the type of strategy adopted by small dairy farms in this state. This information is fundamental in order to establish the monitoring of resistance on each farm individually, contributing to the rational use of acaricides for the control of R. (B.) microplus.
Subject(s)
Cattle Diseases/parasitology , Insecticides , Rhipicephalus/growth & development , Tick Infestations/veterinary , Animals , Cattle , Cattle Diseases/prevention & control , Chlorpyrifos , Female , Insecticide Resistance , Male , Nitriles , Pyrethrins , Surveys and Questionnaires , Tick Infestations/prevention & controlABSTRACT
Leptospiras excretadas pela urina podem sobreviver por longos períodos em águas de superfície e solos, na dependência do pH e teor de umidade e de matéria orgânica. Investigou-se a influência do meio ambiente na transmissão da leptospirose em dois rebanhos exclusivos de ovinos (A e C) e dois de ovinos consorciados com bovinos (F e H) da região de Sorocaba, SP, no período de dezembro de 2007 a setembro de 2008. Foram examinadas amostras de soro pela reação de soroaglutinação microscópica; de urina, água e solo pelo cultivo para leptospiras e urina de ovinos pela PCR. Condições edafoclimáticas, pH das águas de superfície e solo, granulometria e permeabilidade do solo foram analisadas. Todos os rebanhos apresentaram pelo menos um animal sororeagente para Leptospira spp. Apenas a PCR de um pool de urina de ovinos (H) foi positiva. Leptospira spp. foi isolada do lago de F. O pH das águas de superfície variou entre 6,0-7,0; e nos solos entre 4,5 e 6,8. Os índices de matéria orgânica em A, C e H variaram de 24 a 35 g/dm3, e 63 g/dm3 em F. A composição do solo de A e F mostrou-se franco-argiloarenosa, C argilosa e H franco-siltosa; como texturas mistas são capazes de manter a umidade, principalmente devido a argila. Diante da presença de animais sororeatores e portanto da circulação de Leptospira spp. nos rebanhos, conclui-se que o ciclo de transmissão é dependente da interação sinérgica e antagônica de muitas variáveis; onde o pastejo num habitat com alto teor de umidade parece ser limitante.
Leptospires excreted by urine are able to survive for long periods in surface water and soil depending on the pH, humidity and organic matter presence. This paper reported the influence of environment conditions on the transmission of leptospirosis in two sheep-only farms (A and C) and two cattle-sheep farms (F and H) from December 2007 to September 2008. Serum samples were examined by microscopic agglutination test; urine, surface water and soil samples were cultured for leptospires, and ovine urine pools were analyzed by PCR. Regional edaphoclimatic conditions, pH of surface water and soil, granulometry and permeability of soil were analyzed. All herds presented at least one reactor to Leptospira spp. Only the PCR of an ovine urine pool of herd H was positive and Leptospira spp. was isolated from the F lake. The pH of water samples ranged from 6.0 to 7.0; while in soil it was around from 4.5 to 6.8. Soil organic matter were 24 to 35 g/dm3 in A, C e H, and 63 g/dm3 in F. Soil samples of A and F showed loamy-clay texture; C had clay soil, and H loamy-silt soil; as mixed compositions are able to maintain the humidity, mainly where clay is present. As the presence of reactors in all herds indicated the contact with Leptospira spp., it was concluded that the cycle of transmission is dependent on the synergistic and antagonistic interaction of many variables; but the close contact of animals grazing in a high humidity habitat seems to be limiting.