ABSTRACT Most studies regarding the impacts of agricultural systems on soils of the Amazon region of Brazil have been carried out on upland soil, locally known as terra firme. Information regarding the impacts of different land-use systems on floodplain soil properties is still scarce. There is a need to broaden this knowledge to understand this Amazonian ecosystem better, especially how its soils respond to human interventions. This study aimed to describe the major chemical features of floodplain soils along the Solimões-Amazon Rivers and the effects of different land-use systems on soil nutrient levels. Sixty-two different land-use systems were sampled in 15 communities located in three different regions of the Solimões/Amazonas River floodplain complex: Upper and Middle Solimões (UMS), Lower Solimões and Middle Amazon (LSMA), and Lower Amazon (LA). Soils under cultivation showed a high availability of Ca2+, Mg2+, and P and low levels of exchangeable Al, in contrast to soils under forest and secondary vegetation, which were more acid and showed higher levels of exchangeable Al. Although most of the samples showed high contents of K+, for some areas, the low level (K+ <0.15 cmolc kg-1) of this nutrient can become limiting to crop production. The low levels of N found in most of the analyzed samples confirm that this element may be the limiting nutrient for agriculture in floodplain ecosystems. The use of legumes and other nutrient-rich plants, which naturally occur in the Amazon floodplain environments, could potentially address this N deficiency in these soils.

Carrapatos e as doenças por eles transmitidas causam grandes perdas econômicas ao gado dos países tropicais. Alternativas não-químicas incluem o uso de raças de gado que sejam resistentes, controle biológico e vacinas. No entanto, o método mais utilizado é a aplicação de diferentes classes químicas de acaricidas e lactonas macrocíclicas. Populações de piolhos de gado, Rhipicephalus (Boophilus) microplus, resistentes aos organofosfatos (OP), piretoides sintéticos (SP), amitraz e fipronil, foram descritas no México. Lactonas macrocíclicas são as drogas antiparasitárias mais vendidas no mercado veterinário mexicano. Populações de R. (B.) microplus resistentes à irvemectina foram relatadas no Brasil, Uruguai e especialmente no México (Veracruz e Yucatan). Embora os níveis de resistência à ivermectina no R. (B.) microplus do México tenha sido relativamente baixa, na maioria dos casos, algumas populações campestres de R. (B.) microplus mostraram altos níveis de resistência à ivermectina. A população CHPAT mostrou uma razão de resistência de 10,23 e 79,6 na concentração letal de 50% e 99%, respectivamente. Muitas populações campestres de R. (B.) microplussão resistentes a múltiplas classes de drogas antiparasitárias, incluindo organofosfatos (clorpirifós, coumafos e diazinon), piretoides (flumetrina, deltametrina e cipermetrina), amitraz e ivermectina. Este artigo relata o estado atual de resistência do R. (B.) microplus aos acaricidas, especialmente ivermectina, no gado mexicano.

Ticks and the diseases they transmit cause great economic losses to livestock in tropical countries. Non-chemical control alternatives include the use of resistant cattle breeds, biological control and vaccines. However, the most widely used method is the application of different chemical classes of acaricides and macrocyclic lactones. Populations of the cattle tick, Rhipicephalus (Boophilus) microplus, resistant to organophosphates (OP), synthetic pyrethroids (SP), amitraz and fipronil have been reported in Mexico. Macrocyclic lactones are the most sold antiparasitic drug in the Mexican veterinary market. Ivermectin-resistant populations of R. (B.) microplus have been reported in Brazil, Uruguay and especially in Mexico (Veracruz and Yucatan). Although ivermectin resistance levels in R. (B.) microplus from Mexico were generally low in most cases, some field populations of R. (B.) microplus exhibited high levels of ivermectin resistance. The CHPAT population showed a resistance ratio of 10.23 and 79.6 at lethal concentration of 50% and 99%, respectively. Many field populations of R. (B.) microplus are resistant to multiple classes of antiparasitic drugs, including organophosphates (chlorpyrifos, coumaphos and diazinon), pyrethroids (flumethrin, deltamethrin and cypermethrin), amitraz and ivermectin. This paper reports the current status of the resistance of R. (B.) microplus to acaricides, especially ivermectin, in Mexican cattle.

Este estudo foi realizado com o objetivo de se obter uma visão epidemiológica da resistência aos acaricidas nas populações de Rhipicephalus (Boophilus) microplus no Estado de Mato Grosso do Sul. Vinte e quatro amostras de carrapatos foram coletadas em cidades do estado onde os fazendeiros relataram preocupação com resistência ou falha no controle dos carrapatos. Estes carrapatos foram submetidos a testes de detecção de resistência in vitro usando o teste de imersão de adultos (TIA). A eficácia do tratamento com alfa-cipermetrina, cipermetrina e amitraz foi geralmente pobre nas amostras coletadas em todo o Estado. Obteve-se eficácia de >90% no TIA com o DDVP + chlorfenvinphos (20 das 21 cidades), Diclorvós + Cipermetrina (10 das 16 cidades), e Cipermetrina + Citronela + Clorpirifós + Butóxido de piperonila (20 das 21 cidades). O ensaio da PCR foi utilizado para detectar a presença de mutação do gene do canal de sódio associado à resistência a piretróide. Avaliaram-se larvas de três diferentes populações onde anteriormente foi diagnosticada à resistência por TIA. Os ensaios da PCR mostraram que a mutação no gene associado à resistência ao piretróide estava ausente nessas três populações. Esse estudo confirma que o surgimento da resistência é um constante desafio para a pecuária e o desenvolvimento de resistência continua a ser um importante estímulo para o desenvolvimento de novas drogas antiparasitárias.

This study was conducted to obtain an epidemiological view of acaricide resistance in populations of Rhipicephalus (Boophilus) microplus in the State of Mato Grosso do Sul. Twenty-four tick samples were collected from municipalities in the State where farmers had reported concerns about resistance to or failure of tick control. These ticks were subjected to in vitro resistance detection assays using the adult immersion test (AIT). The efficacy of alpha-cypermethrin, cypermethrin and amitraz treatments on samples collected throughout the State was generally poor. AIT showed efficacy > 90% from the use of DDVP + chlorfenvinphos) (20 out of 21 municipalities), dichlorvos + cypermethrin (10 out of 16 municipalities) and cypermethrin + citronella + chlorpyrifos + piperonyl butoxide (20 out of 21 municipalities). PCR assays were used to detect the presence of pyrethroid resistance-associated sodium channel gene mutation. Larvae from three different populations that had previously been diagnosed as pyrethroid-resistant, through AIT, were evaluated. The PCR assays showed that the pyrethroid resistance-associated gene mutation was absent from these three populations. This study confirms that the emergence of resistance is a constant challenge for the livestock industry, and that development of resistance continues to be a major driver for new antiparasitic drugs to be developed.

A variabilidade genética de isolados de Verticillium dahliae oriundos de oliveira (Olea europaea) e de outros hospedeiros na Argentina e Brasil foi estimada através de PCR, usando primers específicos para a amplificação da região espaçadora intergênica do DNA ribossomal (IGS) e de uma porção do gene codificante para a subunidade menor do RNA ribossomal do DNA mitocondrial (mtDNA SSU rRNA). Os fenogramas gerados usando UPGMA, baseados em perfis de restrição da região IGS do rDNA revelaram diferenças genéticas, correlacionadas ao hospedeiro de origem, com isolados originados de oliveira geneticamente distintos daqueles que infetam cacau (Theobroma cacao) e girassol (Helianthus annuus). A digestão dos produtos de PCR do SSU rRNA do DNA mitocondrial revelou menor variabilidade, distinguindo somente um isolado de girassol dos demais. Padrões de restrição da região ITS do rDNA nuclear apresentaram-se idênticos para todos os isolados de V. dahliae, independente de hospedeiro de origem. Estes resultados preliminares podem ter relevância para o desenvolvimento de estratégias de controle das murchas causadas por V. dahliae, possivelmente refletindo uma origem evolucionária diferente, ou isolamento reprodutivo do patógeno causador da murcha em oliveira, que se apresentou distinto de populações originárias de outros hospedeiros.

Using PCR-based assays with specific primers for amplification of the ribosomal DNA intergenic spacer region (IGS) and a portion of the mitochondrial DNA small subunit ribosomal RNA gene (mtDNA SSU rRNA), the genetic variability among Verticillium dahliae isolates from olive (Olea europaea) and other host species from Argentina and Brazil was estimated. The derived UPGMA-generated phenograms based upon the restriction fingerprinting data of rDNA IGS products revealed genetic differences, correlating with the host of origin. Isolates infecting olive genetically distinct from those from cocoa (Theobroma cacao) and sunflower (Helianthus annuus). Digestion of mitochondrial DNA SSU rRNA PCR products revealed less variability, distinguishing only one isolate from sunflower. Ribosomal DNA ITS restriction patterns were identical for all isolates of V. dahliae, irrespective of host of origin. These preliminary results may have relevance for Verticillium wilt control practices, possibly reflecting a different evolutionary origin, or reproductive isolation of the pathogen in olive, distinct from populations of other hosts.

A 1% (W/V) formulation of Niclosamide (2', 5-Dichloro-4-nitrosalicylanilide) (TAP) was tested on Cebus apella monkeys as a topical prophylatic against schistosomiasis mansoni. Two experiments were conducted using the same formulation. In the first experiment, the TAP provided complete protection against schistosomiasis for 3 days. Of the 4 monkeys treated with TAP 7 days before exposure to Schistosoma mansoni cercariae, 2 were completely protected. The remaining 2 monkeys of the 7 day treatment group had a 78% or greater reduction in adult worm buderns when compared to the placebo treated monkeys. The second experiment was designed determine the time between day 3 and 7 when the TAP no longer provided complete protection. However, all of the TAP treated monkeys in this experiment were completely protected, even the monkeys treated 7 days earlier. In both experiments, all monkeys used as infection controls and those receiving only the placebo became infected and showed typical experimental schistosomiasis. These results demonstrate that the TAP could provide fast acting, short-term protection to people who must enter cercariae infested water.

Os índios Waimiri Atroari têm hábitos e costumes bastantes intactos e retiram da floresta, roça e rio os materiais necessários para a alimentação, utensílios e moradia. Este trabalho objetivou fazer um levantamento preliminar do conheciamento e utilização da floresta pelos índios. Foram inventariados todas as árvores com DAP > 6cm em cinco parcelas de 10 x 20m, localizadas 0,5km da aldeia, ao longo de um transecto abrangendo um gradiente de terra firme - baixio. Foram coletadas amostras para herbário e anotadas informações sobre uso e nome indígena. Em 0.1 hectare foram encontradas 135 árvores de 60 espécies, sendo as famílias mais comuns: Lecythidaceae, Leguminosae sensu latu, Burseraceae, Bombacaceae e Lauraceae. Noventa e cinco por cento dessas espécies eram identificadas com um nome específico na língua Waimiri Atroari e as demais receberam um nome genérico ("wiwe ') que quer dizer árvore. De uma amostra de 34 espécies sessenta e cinco por cento tinham algum uso específico. Estes dados demonstram um alto grau de conhecimento e utilização da floresta pelos Waimiri Atroari.

The Waimiri Atroari retain much of their original culture and take from the forest, river, and plantations their food and most of the materials necessary fpr construction, craft, and medicines. This study attempted to quantify their knowledge and use of forest. Five quadrats of 10 x 20m (total = 0,1 hectare) were located along a transition from "terra firme" (upland) to "baixio" (stream valley). Herbarium specimens were collected from trees above 6cm DBH, and Indian names and uses were recorded. In 0,1 hectare, 135 trees belonging to 60 species were found. Lecythidaceae, Leguminosae (sensu latu), Burseraceae, Lauraceae and Bombacaceae were the commonest families. Ninety-five percent of the species received a Waimiri Atroari name, and in a smller sample (n = 34), sixty-five percent of the species had some specific use. These results show a high degree of knowledge and utilization of the forest by the Wairniri Atroari.