ABSTRACT
We analyzed the influence of time, tide and water depth on the activity and spatial distribution of estuarine dolphins Sotalia guianensis in Pontal Bay, Ilhéus, Brazil. Direct observations were carried out at four fixed points from January to December of 2006. Estuarine dolphins were sighted in 11 out of 12 months and in 30 percent of 181 sampling periods. The average group size, which was 3.75 ± 1.59 (n = 64), did not vary significantly by month (Kruskal-Wallis, H = 10.6729; p = 0.3836). Infants and adults represented 18 and 82 percent of the individuals whose age we were able to determine, respectively. Estuarine dolphins were more frequently present than expected in areas deeper than 3 m (regression GLM, z = 3.773; p = 0.0002). The animals were more frequently observed between 7:00 and 8:00 AM and between 3:00 and 5:00 PM (X² = 83.815; p < 0.0001). Their presence in the bay tripled between the fourth hour of the flood and high tide, remaining elevated during the ebb tide (X² = 22.152; p = 0.02). The tide also influenced the animals' feeding and travelling direction, mainly toward the open see during the flood and to the back of the bay during others stages. Further studies are necessary to analyze the influence of the hydrographic characteristics of Pontal Bay on the spatio-temporal distribution of estuarine dolphins and their prey.
Analisamos a influência do horário, da maré e da profundidade de água sobre a atividade e a distribuição espacial do boto-cinza Sotalia guianensis na Baía do Pontal, Ilhéus, Brasil. Observações diretas foram realizadas de quatro pontos fixos de janeiro a dezembro de 2006. Botos-cinza foram avistados em 11 dos 12 meses de observação e em 30 por cento dos períodos de amostragem. O tamanho médio dos grupos foi de 3,75 ± 1,59; (n = 64) e não variou significativamente em função do mês (Kruskal-Wallis, H = 10,6729; p = 0,3836). Infantes e adultos representaram respectivamente 18 e 82 por cento dos indivíduos cuja idade foi determinada. Os botos-cinza foram mais freqüentes em áreas com profundidade superior a 3 m do que esperado (regressão GLM, z = 3,773; p = 0,0002). Os animais foram mais observados entre 7 e 8 horas e entre 15 e 17 horas (X² = 83,815; p < 0.0001). A frequência do boto-cinza na baía triplicou entre a quarta hora de maré enchente e a preamar e sua presença se manteve alta durante a maré de vazante (X² = 22,152; p = 0,02). A maré influenciou também a direção de forrageamento e deslocamento dos botos-cinza, principalmente para o mar aberto durante o preamar e o fundo da baía em outras fases da maré. É necessário estudar a influência das características hidrográficas da Baía do Pontal sobre a distribuição spatio-temporal de S. guianensis e suas presas.
ABSTRACT
Las cepas clásicas del virus de la enfermedad infecciosa de la bolsa (por sus siglas en inglés IBDV) están presentes en la industria avícola venezolana desde el último tercio del siglo pasado, a pesar de la implementación de programas intensivos de vacunación. Recientemente, se ha reportado la presencia de cepas variantes del IBDV en varios países de Latinoamérica. El presente trabajo reporta la identificación, mediante técnicas moleculares, de cepas variantes en granjas avícolas venezolanas. En parvadas de pollos de engorde de cuatro semanas de edad se tomaron bolsas de Fabricio e improntas en la tarjeta Whatman Indicadora Clásica FTA® para evaluación histopatológica y detección molecular, respectivamente. Para la caracterización molecular se utilizó la prueba de reacción en cadena por la polimerasa-transcriptasa reversa (por sus siglas en inglés RT-PCR) acoplada a secuenciación directa de nucleótidos. El peso vivo del ave, el índice peso bolsa/peso corporal, así como el peso y diámetro de la bolsa se consideraron como indicadores de inmunocompetencia a la cuarta semana. Todas las aves muestreadas (n=113) resultaron positivas a IBDV. Los virus provenientes de 10 de las 13 granjas mostraron alta similitud con cepas variantes (A y E). En concordancia con los resultados de RT-PCR, los hallazgos histopatológicos mostraron lesiones relacionadas con IBDV. Los indicadores morfológicos de inmunocompetencia se afectaron significativamente en las granjas donde se detectaron cepas variantes. En Venezuela no se utiliza vacuna viva contra cepas variantes, lo que incrementa el riesgo de inmunosupresión, fallas en los programas de vacunación y la susceptibilidad a enfermedades endémicas.
Classical infectious bursa disease virus (IBDV) has been present in the Venezuelan poultry industry since the last quarter of the past century despite intensive vaccination programs applied to control the disease. Lately, the presence of variant strains has been reported in several Latin-American countries. This work reports the molecular identification of variant IBDV strains in poultry farms from Venezuela. Bursal imprints in Whatman classic indicator FTA® cards and bursa tissues for histopathological analysis were collected from 4-week old broiler flocks. Reverse transcriptase polymerase chain reaction (RT-PCR) and direct nucleotide sequence were used for the virus molecular characterization. The bird´s body weight, the bursal index, the bursa weight and diameter were used to assess the immune status at four weeks of age. All the birds sampled (n =113) were IBDV positive. Viruses from 10 out of 13 farms showed high similarity with the IBDV variant strains (variants A and E). Histopathological findings where consistent with the RT-PCR, results showing IBDV related bursa damage in the infected birds. The immune status indicators were significantly affected in the farms where variant strains were detected. No variant strain live vaccination is currently used in Venezuela, increasing the risk of immunossupression, vaccine failure and susceptibility to endemic diseases.
ABSTRACT
En el presente estudio se analizaron los resultados de sueros de bovinos procesados en la Unidad de Investigación y Diagnóstico de Leptospirosis de la Universidad del Zulia durante el período 1998-2001. De un total de 819 muestras provenientes de la región occidental de Venezuela, procesadas mediante la Técnica de Microaglutinación (MAT), se observó que 38 por ciento animales fueron seropositivos a uno o más serovares. Los serovares icterohaemorrhagiae (49 por ciento), hardjo (45 por ciento) y hebdomadis (44 por ciento) fueron los más frecuentes, sin evidenciar diferencias estadísticamente significativas entre si. En cuanto a la vacunación, se observó un 56 por ciento de seropositividad en animales no vacunados y 26 por ciento en animales vacunados. En relación a la edad, se obtuvo un 46 por ciento de seropositividad en animales mayores de 48 meses de edad, 35 por ciento en animales entre 12 y 48 meses de edad y 100 por ciento en bovinos menores de 12 meses de edad. De 270 animales con registros clínicos completos, 99 por ciento reportaron abortos como signo clínico más relevante, de los cuales el 49 por ciento fueron realmente positivos a leptospirosis. Se concluye que L. icterohaemorrhagiae y L. hardjo, fueron los serovares que circularon mayormente en el ganado bovino en la región occidental de Venezuela desde 1998 hasta 2001, siendo asociados en varias oportunidades a problemas abortivos. También se observó que los animales no vacunados presentaron una mayor seropositividad que los vacunados. Este estudio permitirá establecer una línea base para comparar las seroprevalencias actuales y futuras de la leptospirosis bovina en esta región, aportando información epidemiológica importante que permita el mejoramiento de medidas de prevención y control en contra de esta enfermedad.
Results from bovine serum samples processed at the Unit of Investigation and Diagnose of Leptospirosis of Zulia University, during the period 1998-2001 were analyzed in the present study. From a total of 819 samples submitted across the Western region in Venezuela, 38 percent were positive to one or more serovars by the Microagglutination Test (MAT). The most frequent serovars observed were icterohaemorrhagiae (49 percent), hardjo (45 percent) and hebdomadis (44 percent), however, no statistical significant differences were found between them. In regards to vaccination, 56 percent of the non-vaccinated animals and 26 percent of the vaccinated were seropositive. The age distribution showed that 46 percent of the animals older than 48 months, 35 percent of the animals between 12 and 48 months-old, and 100 percent of the animals younger than 12 months-old were positive to leptospira. From 270 animals with complete clinical records, 99 percent reported abortion as the main clinical sign, and 49 percent of them were indeed positives to leptospirosis. In conclusion, L. icterohaemorrhagiae and L. hardjo were the most common serovars circulating in the cattle population in the Western region in Venezuela between 1998 and 2001, in which several cases were associated with reproductive problems. It was also observed that non-vaccinated animals presented a higher seropositivity than animals that were vaccinated. This study will allow the establishment of a baseline to compare present and future studies on Bovine Leptospirosis in this region, providing important epidemiological information to be used in improving preventive and control measures against this disease.
Subject(s)
Cattle , Animals , Leptospirosis/diagnosis , Leptospirosis/veterinary , Risk Factors , Seroepidemiologic Studies , Veterinary MedicineABSTRACT
Avaliou-se a eficiência de isolados do fungo Metarhizium anisopliae no controle da cigarrinha-das-raízes em cana-de-açúcar, aplicados em quatro doses, uma ou duas vezes ao longo do período de ocorrência da praga. Os ensaios foram conduzidos em três municípios do estado de São Paulo: Guaíra, Iracemápolis e Tarumã. Somente no ensaio conduzido em Tarumã, o fungo mostrou-se eficiente no controle da cigarrinha-das-raízes, reduzindo as populações em até 91,2 por cento, quando aplicado em duas ocasiões, utilizando em cada uma a dose de 1kg/ha de arroz esporulado, na concentração aproximada de 9.10(8)conídeos/g de arroz. A eficiência do fungo em Tarumã foi atribuída às temperaturas mais amenas da região, permitindo o desenvolvimento do ciclo das relações parasito/hospedeiro.
The efficiency of isolates of the fungus Metarhizium anisopliae was evaluated on sugarcane root froghopper, applied at four doses, once or twice during the pest infestation period. The experiments were carried out in three São Paulo State regions: Guaíra, Iracemápolis and Tarumã. Only in the experiment conducted at Tarumã, the fungus was efficient for root froghopper control, reducing the pest population in 91.2 percent, when it was applied twice, using in each application the conidia obtained on 1 kg/ha of rice (9.10(8) conidia/g of rice). The fungus efficiency in Tarumã was attributed to the lower temperatures, favoring the development of the cycle of the relation parasite/host.