Estatística espacial de varredura na detecção de áreas de risco para a cisticercose bovina no estado da Bahia / Spatial scan statistic in the detection of risk areas for bovine cysticercosis in the state of Bahia

No intuito de classificar a distribuição geográfica da procedência dos animais infectados e mensurar as áreas quanto ao risco de se contrair a cisticercose bovina, foi utilizada a análise espacial de varredura para identificação de aglomerados de risco a partir dos casos positivos para o Cysticercus bovis registrados no período de 2006 a 2007, provenientes de seis matadouros frigoríficos do Serviço de Inspeção Federal, distribuídos para fins administrativos em Territórios de Identidade do estado da Bahia. O número de bovinos abatidos foi de 825.951, dentre os quais (0,7%) 5.395 foram diagnosticados positivos para a doença, mediante a inspeção post mortem dos animais. A análise espacial de varredura, por meio do teste da razão de verossimilhança, demonstrou que a distribuição da cisticercose bovina se concentra, com menor probabilidade de ter ocorrido ao acaso, em área geográfica definida, com risco estimado em 13,6, englobando 101 municípios do estado pertencentes aos territórios de Itapetinga, Litoral Sul, Médio Rio de Contas, Vitória da Conquista e Extremo Sul.

In order to identify the spatial geographical distribution of the infected animals and measure the areas under risk of contracting bovine cysticercosis, spatial scan analysis was used to identify clusters of positive bovine for Cysticercus bovis recorded in the period from 2006 to 2007, from six slaughterhouses under the Federal Inspection Service. The number of slaughtered cattle was 825,951, of which (0.7%) 5,395 were diagnosed as positive for the disease, through post-mortem inspection. The spatial scan analysis through the likelihood ratio showed the spatial distribution of bovine cysticercosis concentrated in defined a geographic area less likely to have occurred by chance, with an estimated risk of 13.6. This specific area encompasses 101 municipalities that belong to Itapetinga, Litoral Sul, Médio Rio de Contas, Vitória da Conquista and Extremo Sul Territories of Identification in Bahia State.

An essential need: creating opportunities for veterinary students and graduates to gain an appreciation of responsibilities and opportunities in global veterinary issues.

Globalisation trends and bioterrorism issues have led to new concerns relating to public health, animal health, international trade and food security. There is an imperative to internationalise and strengthen global public health capacity by renewed emphasis on veterinary public health in veterinary education and increasing opportunities for elective experiential learning in public practice programmes for veterinary students. Recent experience with a US-Brazil Higher Education Consortia Program is used as an example of potential ways in which veterinary students can gain an appreciation for global veterinary issues.

Effect of homeopathic medicines on helminth parasitism and resistance of Haemonchus contortus infected sheep.

This study evaluated the effects of homeopathic treatment on control of Haemonchus contortus infection in sheep. Twenty lambs were randomized to three treatments: treated with the homeopathic medicines, Ferrum phosphoricum, Arsenicum album and Calcarea carbonica; treated with a conventional antihelminthic, doramectin, and an untreated control group. Fecal and blood samples were taken from each animal on days 18, 38 and 68 after start of treatment. A significant reduction in number of H. contortus larvae (p<0.01) was observed for animals in the homeopathic treatment group compared to the control group. Fecal egg counts showed negative correlation between haematocrit and haemoglobin concentrations in the homeopathic treatment group (p<0.01); however, the biochemical and immunological parameters showed better correlation, indicating that the homeopathic medicine improved vital functions. Daily weight gain in the homeopathic treatment group was superior to the control and to the antihelminthic groups, 31 and 6.5%, respectively. The cost benefit analysis confirmed that homeopathy group increases economic trend when compared with the other groups.

Remote Sensing and Geographic Information Systems and risk of American visceral leishmaniasis in Bahia, Brazil.

The spatial distribution of American visceral leishmaniasis (VL) was studied within the context of the environmental characteristics of northwest Bahia State in Brazil during an epidemic year. Geographic Information Systems (GIS) and Remote Sensing (RS) were used to characterize the landscape epidemiology of VL in order to identify and map high risk areas and endemic zones in a northwestern Bahia study area. Normalized Difference Vegetation Index (NDVI) was shown to be one of the most important risk factors in the area of study. Low NDVI values were related to high numbers of sand flies and high numbers of human and canine VL positive cases. Caatinga vegetation type was the dominant vegetation type in the endemic area. The use of RS and GIS allowed the identification of classes of VL risk that may be useful information to guide control program interventions.

A global network for the control of snail-borne disease using satellite surveillance and geographic information systems.

At a team residency sponsored by the Rockefeller Foundation in Bellagio, Italy, 10-14 April 2000 an organizational plan was conceived to create a global network of collaborating health workers and earth scientists dedicated to the development of computer-based models that can be used for improved control programs for schistosomiasis and other snail-borne diseases of medical and veterinary importance. The models will be assembled using GIS methods, global climate model data, sensor data from earth observing satellites, disease prevalence data, the distribution and abundance of snail hosts, and digital maps of key environmental factors that affect development and propagation of snail-borne disease agents. A work plan was developed for research collaboration and data sharing, recruitment of new contributing researchers, and means of access of other medical scientists and national control program managers to GIS models that may be used for more effective control of snail-borne disease. Agreement was reached on the use of compatible GIS formats, software, methods and data resources, including the definition of a 'minimum medical database' to enable seamless incorporation of results from each regional GIS project into a global model. The collaboration plan calls for linking a 'central resource group' at the World Health Organization, the Food and Agriculture Organization, Louisiana State University and the Danish Bilharziasis Laboratory with regional GIS networks to be initiated in Eastern Africa, Southern Africa, West Africa, Latin America and Southern Asia. An Internet site, www.gnosisGIS.org, (GIS Network On Snail-borne Infections with special reference to Schistosomiasis), has been initiated to allow interaction of team members as a 'virtual research group'. When completed, the site will point users to a toolbox of common resources resident on computers at member organizations, provide assistance on routine use of GIS health maps in selected national disease control programs and provide a forum for development of GIS models to predict the health impacts of water development projects and climate variation.

Use of thermal and vegetation index data from earth observing satellites to evaluate the risk of schistosomiasis in Bahia, Brazil.

A geographic information system (GIS) was constructed using maps of regional agroclimatic features, vegetation indices and earth surface temperature data from environmental satellites, together with Schistosoma mansoni prevalence records from 270 municipalities including snail host distributions in Bahia, Brazil to study the spatial and temporal dynamics of infection and to identify environmental factors that influence the distribution of schistosomiasis. In an initial analysis, population density and duration (months) of the annual dry period were shown to be important determinants of disease. In cooperation with the National Institute of Spatial Research in Brazil (INPE), day and night imagery data covering the state of Bahia were selected at approximately bimonthly intervals in 1994 (six day-night pairs) from the data archives of the advanced very high resolution radiometer (AVHRR) sensor of the National Oceanic and Atmospheric Administration (NOAA)-11 satellite. A composite mosaic of these images was created to produce maps of: (1) average values between 0 and +1 of the normalized difference vegetation index (NDVI); and (2) average diurnal temperature differences (dT) on a scale of values between 0 and 15 degrees C. For each municipality, NDVI and dT were calculated for a 3x3 pixel (9 km(2) area) grid and analyzed for relationships to prevalence of schistosomiasis. Results showed a statistically significant relationship of prevalence to dT (rho=-0.218) and NDVI (rho=0.384) at the 95% level of confidence by the Spearman rank correlation coefficient. Results support use of NDVI, dT, dry period climatic stress factors and human population density for development of a GIS environmental risk assessment model for schistosomiasis in Brazil.

Geographic information systems and the environmental risk of schistosomiasis in Bahia, Brazil.

A geographic information system was constructed using maps of regional environmental features, Schistosoma mansoni prevalence in 30 representative municipalities, and snail distribution in Bahia, Brazil to study the spatial and temporal dynamics of infection and to identify environmental factors that influence the distribution of schistosomiasis. Results indicate that population density and the duration of annual dry period are the most important determinants of prevalence of schistosomiasis in the areas selected for study. Maximum rainfall, total precipitation during three consecutive months, annual maximum or minimum temperatures, and diurnal temperature difference were not shown to be significant factors influencing S. mansoni prevalence in local populations or distribution of snail hosts. Prevalence of the disease was highest in the coastal areas of the state. Higher prevalence tended to occur in areas with latossolo soil type and transitional vegetation.