338 resultados para tropical reservoirs


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Introduction Rabies is an important zoonosis that occurs in mammals, with bats acting as Lyssavirus reservoirs in urban, rural and natural areas. Rabies cases in bats have been recorded primarily in urban areas in Northwestern State of São Paulo since 1998. This study investigated the circulation of rabies virus by seeking to identify the virus in the brain in several species of bats in this region and by measuring rabies-virus neutralizing antibody levels in the hematophagous bat Desmodus rotundus. Methods From 2008 to 2012, 1,490 bat brain samples were sent to the Universidade Estadual Paulista (UNESP) Rabies Laboratory in Araçatuba, and 125 serum samples from vampire bats that were captured in this geographical region were analyzed. Results Rabies virus was detected in the brains of 26 (2%) of 1,314 non-hematophagous bats using the fluorescent antibody test (FAT) and the mouse inoculation test (MIT). None of the 176 hematophagous bat samples were positive for rabies virus when a virus detection test was utilized. Out of 125 vampire bat serum samples, 9 (7%) had levels of rabies virus neutralization antibodies (RVNAs) that were higher than 0.5IU/mL; 65% (81/125) had titers between 0.10IU/mL and 0.5IU/mL; and 28% (35/125) were negative for RVNAs using the simplified fluorescent inhibition microtest (SFIMT) in BHK21 cells. The observed positivity rate (1.7%) was higher than the average positivity rate of 1.3% that was previously found in this region. Conclusions The high percentage of vampire bats with neutralizing antibodies suggests that recent rabies virus exposure has occurred, indicating the necessity of surveillance measures in nearby regions that are at risk to avoid diffusion of the rabies virus and possible rabies occurrences.

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Introduction Hantavirus infections have been described in several regions in Brazil through seroepidemiological studies. Usually, populations are associated with rural and wild environment mainly due to close contact to species of Sigmodontinae rodents, considered hantavirus reservoirs. Methods A retrospective serosurvey was conducted to access the hantavirus seroprevalence in people living in regions affected by bovine vaccinia outbreaks. Results Sera from 53 patients were analyzed and none of them presented anti-hantavirus IgG antibodies. Conclusions This study presents an opportunity to analyze seronegativity despite close and recurrent contact with known hantavirus reservoirs. Aspects of hantavirus and bovine vaccinia emergence are also discussed.

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INTRODUCTION: Leptospirosis is a re-emerging zoonotic disease of humans and animals worldwide. The disease is caused by pathogenic species of the genus Leptospira. These organisms are maintained in nature via chronic renal infection of carrier animals, which excrete the organisms in their urine. Humans become infected through direct or indirect exposure to infected animals and their urine or through contact with contaminated water and soil. This study was conducted to investigate Leptospira infections as a re-emerging zoonosis that has been neglected in Egypt. METHODS: Samples from 1,250 animals (270 rats, 168 dogs, 625 cows, 26 buffaloes, 99 sheep, 14 horses, 26 donkeys and 22 camels), 175 human contacts and 45 water sources were collected from different governorates in Egypt. The samples were collected from different body sites and prepared for culture, PCR and the microscopic agglutination test (MAT). RESULTS: The isolation rates of Leptospira serovars were 6.9%, 11.3% and 1.1% for rats, dogs and cows, respectively, whereas the PCR results revealed respective detection rates of 24%, 11.3% and 1.1% for rats, dogs and cows. Neither the other examined animal species nor humans yielded positive results via these two techniques. Only six Leptospira serovars (Icterohaemorrhagiae, Pomona, Canicola, Grippotyphosa, Celledoni and Pyrogenes) could be isolated from rats, dogs and cows. Moreover, the seroprevalence of leptospiral antibodies among the examined humans determined using MAT was 49.7%. CONCLUSIONS: The obtained results revealed that rats, dogs and cows were the most important animal reservoirs for leptospirosis in Egypt, and the high seroprevalence among human contacts highlights the public health implications of this neglected zoonosis.

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AbstractINTRODUCTION: This study evaluated the effects of cattle removal on the Culicidae mosquito community structure in a tropical dry forest in Brazil.METHODS: Culicidae were collected during dry and wet seasons in cattle presence and absence between August 2008 and October 2010 and assessed using multivariate statistical models.RESULTS: Cattle removal did not significantly alter Culicidae species richness and abundance. However, alterations were noted in Culicidae community composition.CONCLUSIONS: This is the first study to evaluate the impact of cattle removal on Culicidae community structure in Brazil and demonstrates the importance of assessing ecological parameters such as community species composition.

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Abstract: We herein report human dermatitis caused by the tropical fowl mite Ornithonyssus bursa (Berlese). The cases occurred in an apartment in a residential district of Porto Alegre City, State of Rio Grande do Sul, Brazil, where three members of the same family presented with pruritic lesions on the arms and legs. On inspecting the bathroom, several mites measuring approximately 1.0mm in length were observed coming from a nest of Rufous Hornero, Furnarius rufus (Gmelin). This is the first report of O. bursa in the urban area of Porto Alegre City, from a nest of F. rufus that bites humans.

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In Brazil, more than 99% of malaria cases are reported in the Amazon, and the State of Amazonas accounts for 40% of this total. However, the accumulated experience and challenges in controlling malaria in this region in recent decades have not been reported. Throughout the first economic cycle during the rubber boom (1879 to 1912), malaria was recorded in the entire state, with the highest incidence in the villages near the Madeira River in the Southern part of the State of Amazonas. In the 1970s, during the second economic development cycle, the economy turned to the industrial sector and demanded a large labor force, resulting in a large migratory influx to the capital Manaus. Over time, a gradual increase in malaria transmission was observed in peri-urban areas. In the 1990s, the stimulation of agroforestry, particularly fish farming, led to the formation of permanent Anopheline breeding sites and increased malaria in settlements. The estimation of environmental impacts and the planning of measures to mitigate them, as seen in the construction of the Coari-Manaus gas pipeline, proved effective. Considering the changes occurred since the Amsterdam Conference in 1992, disease control has been based on early diagnosis and treatment, but the development of parasites that are resistant to major antimalarial drugs in Brazilian Amazon has posed a new challenge. Despite the decreased lethality and the gradual decrease in the number of malaria cases, disease elimination, which should be associated with government programs for economic development in the region, continues to be a challenge.

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Discussed are the taxonomy of the Scleria arundinacea-latifoliacomplex, S. mitis, and S. myricocarpa, all controversial and widespread taxa in tropical America. Scleria cerradicola is described as new in the section Hymenolytrum and a range extension of a rare species, Scleria neogranatensis, is noted.

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Some of the trends and characteristics of the isotopic composition oh precipitation in tropical stations are discussed. Stations in small Pacific islands show a variation with latitude, with lower 8-values between 15°N and 1S°S and higher values at higher. Inland stations are depleted in heavy isotopes with respect to coastal stations but sometimes this continental effect is rather complex, as f,or instance in África. Mean monthly 8-values show a remarkable correlation with the amount of precipitation, but the slope variations do not show a clear dependence on the mean long term 8-value,as should be expected theoretically. In Southern American stations the seasonal variations of the meanmonthly 5-values are correlated and they are greater in inland stations due to con-tinentaly. The possible effects of recycling of water vapour by evapotranspiration are also discussed.

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Calyptothecium planifrons (Ren. & Par.) Argent is reported new to the Western Hemisphere based on two recent collections from Brazilian Amazonia, in Pará and Rondônia; C. planifrons was originally described from Madagascar. Forteen Other species of mosses with apparently disjunct distributions between tropical Africa and tropical America are also discussed. It is likely that mos or all of this species discussed will prove to have wider distributions in the tropics when world-wide revisions are carried out.

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A review of the literature on measurements of rain water interception processes by forests is made. Information on Africa, Central and South America, and Asia is given. A general analysis is made and the need to further the measurements under field conditions is stressed.

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Avaliação da precisão da amostragem sistemática em relação a amostragem aleatória, ambas utilizadas em inventários florestais, com base no erro padrão estimado e tendo como parâmetro de comparação, a área basal. Os dois tipos de amostragem foram aplicados em uma população florestal, 100% inventariada (DAP maior ou igual a 25 cm), constituída de 4 blocos experimentais de 24 hectares cada e distribuídos aleatoriamente sobre uma bacia hidrográfica de aproximadamente 600 hectares. Essa área experimental faz parte do projeto de Manejo Ecológico (Bacia 3). O menor erro padrão estimado foi obtido através da amostragem sistemática, mesmo considerando que na amostragem aleatória foram feitos 5 sorteios diferentes para a tomada das unidades amostrais do inventário simulado.

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Apresenta um modelo matemático para expressar a taxa de regeneração natural em florestas tropicais, através dos valores de abundância. 0 modelo proposto e. o seguinte-.tr = { (A1/A0)- 1 }. 100, onde:tr = taxa de regeneração natural em percentagem;A = abundância absoluta = número de indivíduos por unidade de área;A1 = A0 + ne - ns = abundância absoluta final;ne = número de indivíduos que ingressaram no estudo, por germinação ou mudança de categoria de tamanho (in-put)) ;ns = número de indivíduos que saíram do estudo, por morte ou mudança de categoria de tamanho (out-put).-1 = constante que indica a mortalidade.Os resultados demonstram que a floresta está em equilíbrio dinâmico, uma vez que, apresentou um valor de + 0,10% para a taxa de regeneração natural, a qual pode ser utilizada para espécies, grupos de espécies ou para o total da floresta.