Showing papers by "Fernando Ferreira published in 2013"
TL;DR: It is concluded that the preferred source of food of the stray dogs on the University of São Paulo campus was leftover food deliberately offered by restaurant users, which was the main reason to retain this population within the campus.
41 citations
TL;DR: Targeted investigations should be carried out in areas of the state where brucellosis risk was not well explained by the predictors included in the final logistic regression model to determine more precisely the reasons for the unexplained disease excess.
41 citations
TL;DR: Assessment of seroprevalence of orthopoxviruses in domestic and wild animals and farmers from 47 farms in three cities in the southwest region of the state of São Paulo with or without official reports of outbreaks in cattle or humans indicates a low serop revalence in wild animals, suggesting other routes through which VACV can be spread.
Abstract: Vaccinia virus (VACV), the etiological agent of an exanthematic disease, has been associated with several bovine outbreaks in Brazil since the end of the global vaccination campaign against smallpox. It was previously believed that the vaccine virus used for the WHO global campaign had adapted to an unknown wild reservoir and was sporadically re-emerging in outbreaks in cattle and milkers. At present, it is known that Brazilian VACV is phylogenetically different from the vaccinia virus vaccinal strain, but its origin remains unknown. This study assessed the seroprevalence of orthopoxviruses in domestic and wild animals and farmers from 47 farms in three cities in the southwest region of the state of Sao Paulo with or without official reports of outbreaks in cattle or humans. Our data indicate a low seroprevalence of antibodies in wild animals and raise interesting questions about the real potential of wild rodents and marsupials as VACV reservoirs, suggesting other routes through which VACV can be spread.
38 citations
TL;DR: The results of this work reveal a high prevalence of EIAV in the Pantanal area of Brazil demonstrating that equids reared in this region are at great risk of infection.
27 citations
TL;DR: A community detection algorithm was implemented to find livestock communities, which is consistent with the definition of a livestock production zone, assuming that a community is a group of farm premises in which an animal is more likely to stay during its lifetime than expected by chance.
21 citations
TL;DR: It is found that age but not household income is associated with the number of dogs or cats in households that have pets; higher income households were more likely to have dogs when compared to low-income households, contradicting a common belief that the poorer the family, the more likely they have pets.
19 citations
TL;DR: In these areas, dog and cat emergency vaccination (vaccination blockage) was recommended after the halt of the massive vaccination campaign in 2010 and this control strategy was able to increase the proportion of vaccinated animals around a critical value of 50% and even with a higher probability of infectious contact between bats and dogs or cats in the vaccination blockage areas, no dog or cat rabies case was observed.
16 citations
TL;DR: It is found that different networks with the same degree distribution may have distinct structural properties, which means that the dynamics of different phenomena on these networks may differ considerably.
Abstract: We have analysed some structural properties of scale-free networks with the same degree distribution. Departing from a degree distribution obtained from the Barabasi-Albert (BA) algorithm, networks were generated using four additional different algorithms a (Molloy-Reed, Kalisky, and two new models named A and B) besides the BA algorithm itself. For each network, we have calculated the following structural measures: average degree of the nearest neighbours, central point dominance, clustering coefficient, the Pearson correlation coefficient, and global efficiency. We found that different networks with the same degree distribution may have distinct structural properties. In particular, model B generates decentralized networks with a larger number of components, a smaller giant component size, and a low global efficiency when compared to the other algorithms, especially compared to the centralized BA networks that have all vertices in a single component, with a medium to high global efficiency. The other three models generate networks with intermediate characteristics between B and BA models. A consequence of this finding is that the dynamics of different phenomena on these networks may differ considerably.
11 citations
TL;DR: In this paper, the same dogs in southern Brazil were sampled over two years to determine the prevalence, incidence and association of canine leptospirosis with various risk factors, including instability in the dog population and age.
Abstract: Introduction The incidence of canine leptospirosis in Brazil needs to be assessed Methods The same dogs in southern Brazil were sampled over two years to determine the prevalence, incidence and association of canine leptospirosis with various risk factors. Results In 2009, the prevalence was 33 (14.4%) of 228 dogs, with a predominance of serovar Canicola (33.4%). In 2010, 90 dogs were re-evaluated (the remaining dogs were lost to deaths, address changes and donations), and the prevalence was found to be 35 (38.9%) of 90, with the predominant serovar being Icterohaemorrhagiae (51.4%). Moreover, the incidence was 26 of 90 (28.9%), and the disease was statistically associated with age (2009) and street access (2010). Conclusions Our findings revealed instability in the dog population and age to be relevant risk factors for canine leptospirosis.
10 citations
TL;DR: In this paper, the structural properties of scale-free networks with the same degree distribution were analyzed and four additional different algorithms (Molloy-Reed, Kalisky, and two new models named A and B) besides the BA algorithm itself.
Abstract: We have analysed some structural properties of scale-free networks with the same degree distribution. Departing from a degree distribution obtained from the Barabasi-Albert (BA) algorithm, networks were generated using four additional different algorithms (Molloy-Reed, Kalisky, and two new models named A and B) besides the BA algorithm itself. For each network, we have calculated the following structural measures: average degree of the nearest neighbours, central point dominance, clustering coefficient, the Pearson correlation coefficient, and global efficiency. We found that different networks with the same degree distribution may have distinct structural properties. In particular, model B generates decentralized networks with a larger number of components, a smaller giant component size, and a low global efficiency when compared to the other algorithms, especially compared to the centralized BA networks that have all vertices in a single component, with a medium to high global efficiency. The other three models generate networks with intermediate characteristics between B and BA models. A consequence of this finding is that the dynamics of different phenomena on these networks may differ considerably.
9 citations
TL;DR: The best approach for direct diagnosis of B. abortus in organs of infected cows includes the isolation associated with PCR of DNA extracted from the cotyledon by the Santos or PK methods, despite the disadvantages of classical bacteriological methods.
Abstract: This study compared 4 protocols for DNA extraction from homogenates of 6 different organs of cows infected with the Brucella abortus 2308 strain. The extraction protocols compared were as follows: GT (guanidine isothiocyanate lysis), Boom (GT lysis with the carrying suspension diatomaceous earth), PK (proteinase K lysis), and Santos (lysis by boiling and freezing with liquid nitrogen). Positive and negative gold standard reference groups were generated by classical bacteriological methods. All samples were processed with the 4 DNA extraction protocols and amplified with the B4 and B5 primers. The number of positive samples in the placental cotyledons was higher than that in the other organs. The cumulated results showed that the Santos protocol was more sensitive than the Boom (p=0.003) and GT (p=0.0506) methods and was similar to the PK method (p=0.2969). All of the DNA extraction protocols resulted in false-negative results for PCR. In conclusion, despite the disadvantages of classical bacteriological methods, the best approach for direct diagnosis of B. abortus in organs of infected cows includes the isolation associated with PCR of DNA extracted from the cotyledon by the Santos or PK methods.
TL;DR: Results here suggest that BTB is low prevalent in the State of Bahia and that under these conditions epidemiological outbreaks found cannot be explained by spatially-structured factors.
Abstract: A tuberculose bovina (BTB) e uma enfermidade causada pela infeccao pelo Mycobacterium bovis que acomete o homem e diversas especies de mamiferos. A BTB tem grande importância por causar prejuizos economicos nas regioes infectadas e por seu impacto na saude publica. Foi realizado inquerito epidemiologico no Estado da Bahia, entre 2008 e 2010, com o objetivo de estimar a prevalencia e conhecer a distribuicao espaco temporal da enfermidade. O Estado foi estratificado em quatro regioes, cada uma com caracteristicas epidemiologicas e demograficas homogeneas representativas de formas de producao pecuaria. Um total de 18.810 cabecas com idade superior a 2 anos foi amostrado em 1350 propriedades. O teste cervical comparativo foi aplicado em cada animal selecionado, sendo considerados positivos os animais reagentes positivos ou duas vezes inconclusivos. Latitude e Longitude foram tomadas para cada propriedade amostrada com o auxilio do aparelho de Global Positioning System (GPS). O teste de Cuzick-and-Edwards e a analise de rastreio espacial (spatial scan statistic) foram utilizados para identificar qualquer agrupamento espacial de BTB. A prevalencia de rebanho na Bahia, indicando a proporcao de propriedades foco, foi de 1,6% (IC 95%: 1,0% - 2,69% por regiao). Nenhuma evidencia significativa (P<0.05) de aglomeracao espacial ou clustering foi detectada, possivelmente devido a baixa prevalencia da doenca. Estes resultados sugerem que a BTB tem baixa prevalencia no estado da Bahia e que, nestas condicoes epidemiologicas, os focos encontrados nao podem ser explicados por fatores espacialmente estruturados.
TL;DR: In this paper, the authors used five algorithms to generate contact networks with different topological structure but with the same scale-free degree distribution, and simulated the spread of acute and chronic infectious diseases on these networks.
Abstract: The transmission dynamics of some infectious diseases is related to the contact structure between individuals in a network. We used five algorithms to generate contact networks with different topological structure but with the same scale-free degree distribution. We simulated the spread of acute and chronic infectious diseases on these networks, using SI (Susceptible – Infected) and SIS (Susceptible – Infected – Susceptible) epidemic models. In the simulations, our objective was to observe the effects of the topological structure of the networks on the dynamics and prevalence of the simulated diseases. We found that the dynamics of spread of an infectious disease on different networks with the same degree distribution may be considerably different.
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TL;DR: Five algorithms are used to generate contact networks with different topological structure but with the same scale-free degree distribution to simulate the spread of acute and chronic infectious diseases on SI and SIS epidemic models.
Abstract: The transmission dynamics of some infectious diseases is related to the contact structure between individuals in a network. We used five algorithms to generate contact networks with different topological structure but with the same scale-free degree distribution. We simulated the spread of acute and chronic infectious diseases on these networks, using SI (Susceptible - Infected) and SIS (Susceptible - Infected - Susceptible) epidemic models. In the simulations, our objective was to observe the effects of the topological structure of the networks on the dynamics and prevalence of the simulated diseases. We found that the dynamics of spread of an infectious disease on different networks with the same degree distribution may be considerably different.