Wearable near-infrared spectroscopy: reliability and sensitivity among different endurance cycling exercise intensities.

The present study investigated the reliability and sensitivity of a wearable near-infrared spectroscopy (wNIRS) device in moderate and heavy exercise intensity domains. On three separate days, eleven males performed an incremental test to exhaustion, and in the following visits, four submaximal constant-load bouts (i.e., test and retest) were performed in the moderate-intensity domain (100 and 130 W) and heavy-intensity domain (160 and 190 W). The local tissue oxygen saturation index (SmO2) and pulmonary oxygen uptake (V̇O2) were measured continuously. The absolute SmO2 and V̇O2 values and the change (Δ) from the 3rd to 6th min of exercise were calculated. There was good reliability for SmO2 measurements, as indicated by the high intraclass correlation coefficient analysis (ICC ≥0.84 for all) and low coefficient of variation between the two trials (CV ≤4.1% for all). Steady-state responses were observed for SmO2 and V̇O2 from the 3rd to the 6th min in the two moderate-intensity bouts (P>0.05), whereas SmO2 decreased and V̇O2 increased from the 3rd to the 6th min in the two heavy-intensity bouts (P<0.05). Together, these findings suggested that the SmO2 measured with a wNIRS device is reliable and sensitive to track local metabolic changes provoked by slight increments in exercise intensity.

Wearable near-infrared spectroscopy: reliability and sensitivity among different endurance cycling exercise intensities

The present study investigated the reliability and sensitivity of a wearable near-infrared spectroscopy (wNIRS) device in moderate and heavy exercise intensity domains. On three separate days, eleven males performed an incremental test to exhaustion, and in the following visits, four submaximal constant-load bouts (i.e., test and retest) were performed in the moderate-intensity domain (100 and 130 W) and heavy-intensity domain (160 and 190 W). The local tissue oxygen saturation index (SmO2) and pulmonary oxygen uptake (V̇O2) were measured continuously. The absolute SmO2 and V̇O2 values and the change (Δ) from the 3rd to 6th min of exercise were calculated. There was good reliability for SmO2 measurements, as indicated by the high intraclass correlation coefficient analysis (ICC ≥0.84 for all) and low coefficient of variation between the two trials (CV ≤4.1% for all). Steady-state responses were observed for SmO2 and V̇O2 from the 3rd to the 6th min in the two moderate-intensity bouts (P>0.05), whereas SmO2 decreased and V̇O2 increased from the 3rd to the 6th min in the two heavy-intensity bouts (P<0.05). Together, these findings suggested that the SmO2 measured with a wNIRS device is reliable and sensitive to track local metabolic changes provoked by slight increments in exercise intensity.

Effect of ultrasonic activation on the reduction of bacteria and endotoxins in root canals: a randomized clinical trial.

AIM: This randomized clinical trial aimed to compare the effectiveness of ultrasonic activation with that of nonactivated irrigation on the removal of bacteria and endotoxin from root canals. METHODOLOGY: Fifty patients with necrotic pulps and asymptomatic apical periodontitis were randomly allocated into two groups according to the final irrigation protocol after root canal preparation: Group UI - ultrasonic irrigation (n = 25) and Group NI - needle irrigation (n = 25). The root canals were medicated with calcium hydroxide for 14 days. Microbiological sampling was performed before (S1) and after the root canal preparation (S2), after the irrigation protocols (S3) and after the removal of the intracanal medication (S4). Total bacteria counts were determined by qPCR and the endotoxin levels by the limulus amebocyte lysate assay. Intragroup analyses were performed using the Wilcoxon test for related samples, whereas intergroup analyses were performed using the Mann-Whitney U-test (P < 0.05). RESULTS: All S1 samples were positive for bacteria, with median numbers of 1.49 × 106 and 8.55 × 105 bacterial cells for the UI and NI groups, respectively. This number significantly decreased in S2 samples (UI: 1.41 × 104 ; NI: 3.53 × 104 ; both with P < 0.001). After final irrigation protocols, there was a significant decrease in bacterial load from S2 to S3 samples in both groups (UI: 4.29 × 103 ; NI: 1.08 × 104 ; P < 0.01). Intergroup analysis revealed a significant difference between irrigation methods regarding bacterial counts in S3 samples (P < 0.05). In contrast, no significant differences were observed between groups for endotoxin levels (P > 0.05). CONCLUSIONS: Ultrasonic activation was more effective than nonactivated irrigation for reducing the number of bacteria but not the endotoxin levels in root canals of teeth with apical periodontitis.

OSTEOPONTIN IN MIXED BENIGN AND MALIGNANT MAMMARY TUMORS OF BITCHES. IMMUNOHISTOCHEMICAL STUDY / Osteopontina em tumores mamários mistos benignos e malignos de cadelas. Estudo imuno-histoquímico.

A osteopontina (OPN) é uma glicoproteína fosforilada extracelular com importância em um grande número de eventos fisiológicos e patológicos. Seus níveis são elevados em tumores e no plasma de pacientes humanos com câncer de mama metastático, sendo considerada um marcador de prognóstico. Não há informações na literatura sobre os níveis plasmáticos de OPN em cães ou em neoplasias mamárias nessa espécie. Este trabalho teve como objetivo pesquisar a imunorreatividade em células de origem epitelial em neoplasias da glândula mamária de cadelas utilizando-se o anticorpo anti-osteopontina. Foram selecionados 10 casos de tumores mistos mamários caninos benignos e 10 malignos, ou seja, do tipo carcinoma em tumor misto. A técnica utilizada foi imuno-histoquímica, com desmascaramento de antígenos pelo calor, inibição de peroxidase endógena e emprego do complexo Avidina Biotina Peroxidase (ABC). A revelação da reação foi feita com DAB. A observação foi em microscopia de luz, com a contagem do nú

Influence of the halothane gene (HAL) on pork quality in two commercial crossbreeds.

We evaluated the effect of the halothane (HAL) gene on the quality of pork in domestic pigs. Half-carcasses from two different commercial pig (Sus domestica) crossbreeds were analyzed, 46 of which were homozygous dominant (HAL(NN)) and 69 of which were heterozygous (HAL(Nn)) for the halothane gene. The measures included backfat thickness, lean meat percentage, carcass weight, pH 24 h after slaughtering, color, and drip loss; DNA was extracted from the haunch muscle. Swine with the HAL(Nn) genotype had less backfat thickness and higher lean meat percentages than swine with the HAL(NN) genotype. Yet, swine with the HAL(Nn) genotype had lower quality meat than those with the HAL(NN) swine. The pH at 24 h was lower in HAL(Nn) swine. The meat color was paler in HAL(Nn) animals, the drip loss was greater in those animals bearing the n allele, and the amount of intramuscular fat was not related to the halothane genotype. We conclude that bearers of the recessive allele of the halothane gene produce more meat, but with quality parameters that are inferior to those sought by consumers and industry.

Influence of Chinese breeds on pork quality of commercial pig lines.

We compared carcass and meat quality of pigs from the same sire line and two different dam lines, one that included Chinese breeds and one that did not. Line A consisted of 1/4 Landrace, 1/2 Large White, 1/8 Chinese breeds (Meishan, Fengjing, Jiaxing), and 1/8 Large White, Duroc and Pietrain, and line B consisted of 1/2 Large White and 1/2 Pietrain. The animals (N = 144) were slaughtered at a live weight of 108 kg. Backfat thickness, percentage of lean meat, pH 24 h after slaughter, meat color, percentage of drip loss, and percentage of intramuscular fat were measured and compared using analysis of variance in a completely randomized design; the BioEstat 5.0 test was applied for the comparison of means at a significance level of 5% for all analyses. Backfat was significantly lower for line A (12.78 mm) than for line B (15.90 mm). The pH measured 24 h after slaughter was significantly lower in line A (5.68) compared to line B (5.84). Percent lean meat was significantly higher for line A (61.21%) compared to line B (59.72%). Percentage drip loss was significantly higher in line A (2.73%) than in line B (2.23%). Percentage intramuscular fat and meat color were not significantly different between the lines. The inclusion of Chinese breeds produced a higher percentage of lean meat and reduced fat thickness, along with increased heterosis, which are important characteristics for breeding programs.

Reactivity of p53 protein in canine transmissible venereal tumor / Reatividade da proteína P53 no tumor venéreo transmissível canino

The expression of p53 protein was evaluated in canine transmissible venereal tumor (CTVT), as following: natural occurrence (n=8); resistant to chemotherapy (n=4); and allogeneic transplanted in progression (n=8), stable (n=8), and regression (n=8)stages. The collected specimens were submitted to GM1 immunohistochemical reaction. Results showed a mean percentage of immunomarked cells around 18.6 percent in CTVT of natural occurrence, 23.8 percent in CTVT resistant to chemotherapy, 22.9 percent in allogeneic transplanted CTVT in both progression and stable stages, and 35.8 percent in transplanted CTVT in regression stage. The results suggest that there is a functional abnormality in p53 gene and its products in the studied tumors; although, it is not possible to correlate the percentage of cells marked by p53 and a prognosis.(AU)

A expressão da proteína p53 foi avaliada em espécimes de tumor venéreo transmissível canino (TVT) de ocorrência natural (n=8); resistente à quimioterapia (n=4) e transplantado em cão nas fases de progressão tumoral (n=8), de latência (n=8) e de regressão (n=8). Os espécimes foram submetidos à reação de imunoistoquímica. Os resultados mostraram porcentagem média de células imunomarcadas de 18,6 por cento no TVT de ocorrência natural, de 23,8 por cento no TVT refratário, 22,9 por cento nos TVTs transplantados nas fases de progressão e latência e de 35,8 por cento na fase de regressão. Os resultados sugerem que há uma anormalidade funcional no gene P53 e seus produtos nos tumores estudados, apesar de não ser possível correlacionar a porcentagem de células marcadas pelo p53 ao prognóstico.(AU)

Reactivity of p53 protein in canine transmissible venereal tumor / Reatividade da proteína P53 no tumor venéreo transmissível canino

The expression of p53 protein was evaluated in canine transmissible venereal tumor (CTVT), as following: natural occurrence (n=8); resistant to chemotherapy (n=4); and allogeneic transplanted in progression (n=8), stable (n=8), and regression (n=8)stages. The collected specimens were submitted to GM1 immunohistochemical reaction. Results showed a mean percentage of immunomarked cells around 18.6 percent in CTVT of natural occurrence, 23.8 percent in CTVT resistant to chemotherapy, 22.9 percent in allogeneic transplanted CTVT in both progression and stable stages, and 35.8 percent in transplanted CTVT in regression stage. The results suggest that there is a functional abnormality in p53 gene and its products in the studied tumors; although, it is not possible to correlate the percentage of cells marked by p53 and a prognosis.

A expressão da proteína p53 foi avaliada em espécimes de tumor venéreo transmissível canino (TVT) de ocorrência natural (n=8); resistente à quimioterapia (n=4) e transplantado em cão nas fases de progressão tumoral (n=8), de latência (n=8) e de regressão (n=8). Os espécimes foram submetidos à reação de imunoistoquímica. Os resultados mostraram porcentagem média de células imunomarcadas de 18,6 por cento no TVT de ocorrência natural, de 23,8 por cento no TVT refratário, 22,9 por cento nos TVTs transplantados nas fases de progressão e latência e de 35,8 por cento na fase de regressão. Os resultados sugerem que há uma anormalidade funcional no gene P53 e seus produtos nos tumores estudados, apesar de não ser possível correlacionar a porcentagem de células marcadas pelo p53 ao prognóstico.

Soja semi-integral extrusada sobre o desempenho de leitões na fase inicial e efeitos residuais nas fases de crescimento e terminação / Levels of extruded semi-integral soybean on the performance of piglets in the initial phase and the residual effects in the growing and finishing phases

Com o objetivo de avaliar os efeitos da substituição da proteína do farelo de soja (FS), pela proteína da soja semi-integral extrusada (SSIE), sobre o desempenho de leitões na fase inicial e a existência ou não de efeitos residuais nas fases de crescimento e terminação, foram conduzidos dois experimentos. No Experimento 1, as porcas lactantes e os leitões lactentes, receberam rações contendo FS, enquanto que no Experimento 2, as porcas, a partir de 109 dias de gestação e na lactação, e os leitões lactentes, consumiram rações sem FS. Os tratamentos experimentais foram: SSIE 0 -dieta controle, composta principalmente por milho e FS, sem inclusão de SSIE, e SSIE 25, 50, 75 e 100, com substituição da proteína do FS pela proteína da SSIE nas concentrações de 25, 50, 75 e 100%, respectivamente. Utilizou-se o delineamento em blocos casualizados, com cinco tratamentos, seis repetições e um animal constituindo a unidade experimental. Observou-se diminuição no ganho diário de peso dos leitões na fase total, desta forma não é recomendada a substituição da proteína do FS pela proteína da SSIE, quando os animais têm contato com o FS na fase de aleitamento. Por outro lado, quando as porcas lactantes e os leitões recebem ração sem FS, observa-se melhor conversão alimentar e recomenda-se 49,03% de substituição, em virtude de determinar o menor consumo diário de ração, sem efeitos sobre o ganho diário de peso.

Two experiments were conducted to evaluate the effects of soybean meal (SM) protein replacement with extruded semi-integral soybean (SSIE) protein on piglet performance in the starter phase and residual effects on the growth and finishing phases. In the first experiment, lactating sows and weaning pigs were fed diets containing SM. In the second experiment, sows (from 109 d of gestation and during lactation) and weaning piglets were fed diets without SM. The treatments were 0%, 25%, 50%, 75% and 100% SSIE of replacement of the SM protein. A randomized block design was used with five treatments and six replicates, and one animal was considered an experimental unit for each experiment. A lower daily weight gain average observed during the total phase suggests that replacing SM protein with SSIE protein when animals come into contact with SM in the weaning phase, is not recommended; moreover, better feed conversion was observed when lactating sows and weaning piglets received diets without SM. A 49.03% replacement of SM protein with SSIE protein is recommended, due to the smaller daily feed intake and no change in daily weight gain in these phase.

SOJA SEMI-INTEGRAL EXTRUSADA SOBRE O DESEMPENHO DE LEITÕES NA FASE INICIAL E EFEITOS RESIDUAIS NAS FASES DE CRESCIMENTO E TERMINAÇÃO

Com o objetivo de avaliar os efeitos da substituição da proteína do farelo de soja (FS), pela proteína da soja semi-integral extrusada (SSIE), sobre o desempenho de leitões na fase inicial e a existência ou não de efeitos residuais nas fases de crescimento e terminação, foram conduzidos dois experimentos, sendo que no Exp. 1, as porcas lactantes e os leitões lactentes, receberam rações contendo farelo de soja, enquanto que no Exp 2, as porcas, a partir de 109 dias de gestação e na lactação, e os leitões lactentes, consumiram rações sem farelo de soja. Os tratamentos experimentais foram: SSIE 0 - dieta controle, composta principalmente por milho e farelo de soja, sem inclusão de SSIE, e SSIE 25, 50, 75 e 100, com substituição da proteína do FS pela proteína da SSIE nas concentrações de 25, 50, 75 e 100%, respectivamente. Utilizou-se o delineamento em blocos casualizados, com cinco tratamentos, seis repetições e um animal constituindo a unidade experimental. Conclui-se que com a queda observada no ganho diário de peso dos leitões na fase total, não é recomendada a substituição da proteína do FS pela proteína da SSIE, quando os animais têm contato com o farelo de soja na fase de aleitamento. Por outro lado, quando as porcas lactantes e os leitões recebem ração sem farelo de soja, observa-se melhor conversão alimentar e recomenda-se 49,03% de substituição, em virtude de determinar

PIT1 gene polymorphism in Pietrain and Large White pigs after divergent selection.

We examined the polymorphisms in the PIT1 gene of 103 pigs and compared their frequencies in the maternal and paternal lineages of the Pietrain and Large White breeds, which have undergone divergent selection for over 30 years. DNA samples extracted from the blood of these animals were amplified by PCR and genotyped by RFLP, using the restriction enzyme RsaI. The data were analyzed with the chi-square test. We found that 57.3% of the animals were genotype AB, among which 26.2% were of the Large White paternal lineage, 18.5% the Pietrain paternal lineage and 12.6% the Pietrain maternal lineage. The AA genotype appeared in 20.4%, of which 7.8% were Large White, 4.8% the Pietrain paternal lineage and 7.8% the Pietrain maternal lineage. BB was observed in 22.3% (6.8% were of the Large White paternal lineage, 9.7% of the Pietrain paternal lineage and 5.8% of the Pietrain maternal lineage). The allele frequencies were 49.0% A and 51.0% B allele. When we examined the Pietrain maternal and paternal lineages, we found that the PIT1 gene had been fixed in the paternal lineage, suggesting that the B allele is associated with low body fat and improved muscle development when compared to the maternal lineage. However, no significant differences were found between the Pietrain and Large White paternal lineages.

Effect of single nucleotide polymorphisms of CAPN1 and CAST genes on meat traits in Nellore beef cattle (Bos indicus) and in their crosses with Bos taurus.

The objectives of this work were to study the segregation of single nucleotide polymorphisms of the calpain 1, large subunit (CAPN1) and calpastatin (CAST) genes in Nellore (Bos indicus) and Nellore xBos taurus beef cattle, as well as to evaluate their effects on meat traits. For this, 300 animals, including 114 Nellore, 67 Angus x Nellore, 44 Rubia Gallega x Nellore, 41 Canchim, 19 Brangus three-way crosses and 15 Braunvieh three-way crosses, were genotyped for the CAPN4751 [AF_248054.2:g.6545C>T (GenBank accession AF248054.2)] and CAST/DdeI [AF_159246.1:g.2959A>G (GenBank accession AF159246.1)] polymorphisms and phenotyped for Ribeye Area, Backfat Thickness, Intramuscular Fat, Shear Force (SF) and Myofibrillar Fragmentation Index (MFI). In relation to the CAPN4751 polymorphism, a frequency of 10.5% was observed for the C allele in the Nellore breed. In the total sample of studied animals, a significant association was found between genotypes and meat tenderness, assessed by SF (P = 0.005) and MFI (P = 0.008), with genotype CT being more favourable than TT. For the CAST/DdeI polymorphism, a frequency of 55.7% was found for the A allele in the Nellore breed. In the total sample, a significant association was observed between genotypes and meat tenderness - SF (P = 0.004) and MFI (P = 0.006), with genotype AA being more favourable than AG. The relationship between genotypes and aged meat tenderness in confluence with the distribution of favourable alleles shows great potential for application of the CAPN4751 and CAST/DdeI polymorphisms in the genetic improvement of the Nellore breed, whilst contributing to the validation, in this breed and in its crosses with B. taurus, of the association results previously described in the literature.

Analysis of 724 cases of primary head and neck squamous cell carcinoma (HNSCC) with a focus on young patients and p53 immunolocalization.

This study evaluated 724 primary head and neck squamous cell carcinoma (HNSCC) in young and old patients, with regard to clinical profile and immunohistochemical expression of p53 protein. Associations among age, epidemiological and clinicopathological parameters, and survival analysis were evaluated. HNSCC in young people occurred in 14.5% (median age 40.7years; male-to-female ratio 5.9:1). A statistical association was demonstrated between age and family history of cancer, and between age and anatomical site. Among older patients, a higher presence of disease was noted in posterior sites. Expression of p53 was found in 71.7% of the samples and a higher expression was noted in lesions of young patients. Survival analysis showed that the age parameter is not a reliable prognostic factor for HNSCC. Among young patients, cervical metastasis was associated with worse survival. The presence of a family history of cancer in young patients could indicate genetic susceptibility and molecular disturbances in the p53 pathway in HNSCC of young and older patients seem to be distinct.

Obese gene polymorphism in Pietrain and Large White pigs after a divergent selection.

The aim of the present study was to identify polymorphisms in the leptin gene of 112 pigs and compare the maternal and paternal lineage of Pietrain and Large White breeds that underwent a divergent selection for over 30 years. DNA samples extracted from the blood of these animals were amplified by polymerase chain reaction and genotyped by restriction fragment length polymorphism using the restriction enzyme HinfI. The data were statistically analyzed by the chi-square test. The results showed that 87.5% of the animals were genotype TT, where 31.25% were Large White paternal lineage, 31.25% were Pietrain paternal lineage and 25% were Pietrain maternal lineage. The TC genotype appeared in 12.5%, where 10% were Large White, 0.5% were Pietrain paternal lineage and 2% were of the same maternal lineage breed; CC was not observed. As for the allele frequency, 93.75% of the T and 6.25% of the C allele were found. In Pietrain maternal and paternal lineages, it could not be determined that the Obese gene had been fixed in the maternal lineage. However, in the Pietrain and Large White paternal lineages there was a statistically significant difference, suggesting that the C allele is associated with growth and daily weight gain and that the low frequency of C in the Pietrain lineage is related to low rate of body fat, a typical feature of this breed.

Neurogenesis of GABAergic cells in the retina of malnourished rats.

The present study investigated how prenatal protein malnutrition affects the neurogenesis of GABAergic cells in the retina. Rats were treated with a multi-deficient diet, with only 8% of protein that was administered during the gestational and suckling periods. Pregnant mothers and pups from malnourished and control (fed with 22% protein) groups received a single intra-peritoneal injection of [3H]-thymidine at six developmental ages, from E14 to PN4, and the pups were sacrificed at PN18. Eyes were enucleated and cryosections of the retina were double labeled for GABA-immunocytochemistry and for autoradiography. The percentage of double labeled cells, in the retinal inner nuclear and ganglion cell layers, was determined for both groups. Qualitative and quantitative results showed that double labeled cells [GABA+/thymidine+] were present since E14, when mitotic activity for GABAergic cells starts, in both GCL and INL layers. The peak rate of GABAergic cell generation was reached in control animals injected with [3H]-thymidine at E18 in both central and peripheral sectors of the retina, but only at E20 in the malnourished group. The generation of cells of GABA phenotype showed a significant delay in both layers of the retina in the malnourished group. At PN4, close to the age that GABAergic mitotic activity ends in the control group, double labeled cells were significantly higher in the malnourished group. Our data showed a delay in GABAergic cell generation in the malnourished group when compared to the control group that might result in significant functional consequences in the developing retina.

Quantitative ultrastructural evidence of myelin malformation in optic nerves of rats submitted to a multideficient diet.

Pups were subjected to malnutrition by feeding the lactating mothers a multi-deficient (8% protein content) diet, known as regional basic diet (RBD), from birth up to weaning. The weanings were fed the same diet until 60 days of age. Ultrastructure of the optic nerve was analyzed at postnatal (P) day P8, P13, P21, P30 and P60. Electron microscopy revealed that at P8 the process of myelination has not started yet in neither groups. At P 13 different stages of myelination were observed and, in the experimental group, the optic nerve showed non-organized axon bundles and empty spaces. Control optic nerve at P21 exhibited axons with fully developed myelin sheath; whereas malnourished group had many axons being enveloped by myelin with anomalous alteration. These alterations were present in malnourished group at P30 and P60. Quantitative analysis showed statistically significant difference between control and malnourished groups when compared to the percentage of myelinated axons, axons with myelin anomalous alterations (MAA) and non-myelinated axons. Also, the myelin area was significantly smaller in malnourished groups when compared to control group. Finally, a high percentage of large non-myelinated fibers were found in the malnourished group. In conclusion, our results show that early malnutrition by a multideficient diet (RBD) affects permanently the optic nerve organization and myelination, indicating an impairment of nerve transmission and a probable dysfunction in the visual ability.

The impact of Chagas disease control in Latin America: a review.

Discovered in 1909, Chagas disease was progressively shown to be widespread throughout Latin America, affecting millions of rural people with a high impact on morbidity and mortality. With no vaccine or specific treatment available for large-scale public health interventions, the main control strategy relies on prevention of transmission, principally by eliminating the domestic insect vectors and control of transmission by blood transfusion. Vector control activities began in the 1940s, initially by means of housing improvement and then through insecticide spraying following successful field trials in Brazil (Bambui Research Centre), with similar results soon reproduced in São Paulo, Argentina, Venezuela and Chile. But national control programmes only began to be implemented after the 1970s, when technical questions were overcome and the scientific demonstration of the high social impact of Chagas disease was used to encourage political determination in favour of national campaigns (mainly in Brazil). Similarly, large-scale screening of infected blood donors in Latin America only began in the 1980s following the emergence of AIDS. By the end of the last century it became clear that continuous control in contiguous endemic areas could lead to the elimination of the most highly domestic vector populations - especially Triatoma infestans and Rhodnius prolixus - as well as substantial reductions of other widespread species such as T. brasiliensis, T. sordida, and T. dimidiata, leading in turn to interruption of disease transmission to rural people. The social impact of Chagas disease control can now be readily demonstrated by the disappearance of acute cases and of new infections in younger age groups, as well as progressive reductions of mortality and morbidity rates in controlled areas. In economic terms, the cost-benefit relationship between intervention (insecticide spraying, serology in blood banks) and the reduction of Chagas disease (in terms of medical and social care and improved productivity) is highly positive. Effective control of Chagas disease is now seen as an attainable goal that depends primarily on maintaining political will, so that the major constraints involve problems associated with the decentralisation of public health services and the progressive political disinterest in Chagas disease. Counterbalancing this are the political and technical cooperation strategies such as the "Southern Cone Initiative" launched in 1991. This international approach, coordinated by PAHO, has been highly successful, already reaching elimination of Chagas disease transmission in Uruguay, Chile, and large parts of Brazil and Argentina. The Southern Cone Initiative also helped to stimulate control campaigns in other countries of the region (Paraguay, Bolivia, Peru) which have also reached tangible regional successes. This model of international activity has been shown to be feasible and effective, with similar initiatives developed since 1997 in the Andean Region and in Central America. At present, Mexico and the Amazon Region remain as the next major challenges. With consolidation of operational programmes in all endemic countries, the future focus will be on epidemiological surveillance and care of those people already infected. In political terms, the control of Chagas disease in Latin America can be considered, so far, as a victory for international scientific cooperation, but will require continuing political commitment for sustained success.

The impact of Chagas disease control in Latin America: a review

Discovered in 1909, Chagas disease was progressively shown to be widespread throughout Latin America, affecting millions of rural people with a high impact on morbidity and mortality. With no vaccine or specific treatment available for large-scale public health interventions, the main control strategy relies on prevention of transmission, principally by eliminating the domestic insect vectors and control of transmission by blood transfusion. Vector control activities began in the 1940s, initially by means of housing improvement and then through insecticide spraying following successful field trials in Brazil (Bambui Research Centre), with similar results soon reproduced in Säo Paulo, Argentina, Venezuela and Chile. But national control programmes only began to be implemented after the 1970s, when technical questions were overcome and the scientific demonstration of the high social impact of Chagas disease was used to encourage political determination in favour of national campaigns (mainly in Brazil). Similarly, large-scale screening of infected blood donors in Latin America only began in the 1980s following the emergence of AIDS. By the end of the last century it became clear that continuous control in contiguous endemic areas could lead to the elimination of the most highly domestic vector populations - especially Triatoma infestans and Rhodnius prolixus - as well as substantial reductions of other widespread species such as T. brasiliensis, T. sordida, and T. dimidiata, leading in turn to interruption of disease transmission to rural people. The social impact of Chagas disease control can now be readily demonstrated by the disappearance of acute cases and of new infections in younger age groups, as well as progressive reductions of mortality and morbidity rates in controlled areas. In economic terms, the cost-benefit relationship between intervention (insecticide spraying, serology in blood banks) and the reduction of Chagas disease (in terms of medical and social care and improved productivity) is highly positive. Effective control of Chagas disease is now seen as an attainable goal that depends primarily on maintaining political will, so that the major constraints involve problems associated with the decentralisation of public health services and the progressive political disinterest in Chagas disease. Counterbalancing this are the political and technical cooperation strategies such as the "Southern Cone Initiative" launched in 1991...