Prevalence and spatial distribution of bovine brucellosis in San Luis and La Pampa, Argentina.

BACKGROUND: Bovine brucellosis (BB) is a zoonotic disease caused by Brucella abortus. BB is endemic in Argentina, where vaccination with Brucella abortus strain 19 is compulsory for 3-to-8 month-old heifers. The objectives of this study were to quantify the prevalence of BB and to identify factors associated with its occurrence, along with the spatial distribution of the disease, in the provinces of La Pampa and San Luis. A two-stage random sampling design was used to sample 8,965 cows (3,513 in La Pampa and 5,452 in San Luis) from 451 farms (187 in La Pampa and 264 in San Luis). RESULTS: Cow and herd prevalence were 1.8 % (95 % CI: 1.3-2.2; n = 157) and 19.7 % (95 % CI: 17.0-22.4; n = 89), respectively. Both cow-level and herd-level prevalence in La Pampa (2.4 and 26.0 %, respectively) were significantly higher than in San Luis (1.4 and 15.5 %, respectively). There were not differences between the proportions of reactive cattle compared to that obtained in a survey conducted in 2005. However, herd prevalence in La Pampa was significantly (P < 0.05) higher compared to that study. Disease was found to be spatially clustered in west La Pampa. The lower the bovine density and the calf/cow ratio, the higher odds of belonging to the cluster. CONCLUSIONS: The increase of farm prevalence in the last five years suggests that the disease is spreading and that control measures should be applied in the region. The cluster of infected farms was located in the west region of La Pampa. There, farms have lower animal densities and smaller cow/calf indices compared to the rest of the province. Although western La Pampa has more infected herds, within-farm prevalence was not higher, which suggests that the control program has been relatively successful in controlling the disease at the farm level, and/or that low animal density inherently results in low disease prevalence. Our results provide baseline information on the epidemiology of BB and its potential pattern of transmission in Argentina, which will ultimately help to improve BB control programs in the country.

Importance of foot and mouth disease vaccine purity in interpreting serological surveys.

The aim of this study was to determine whether the degree of purity achieved in conventional vaccines against the foot and mouth disease virus in Argentina interferes with the interpretation of seroepidemiological surveys for confirming the absence of viral activity, which are performed to support the recognition of free zones practising vaccination. The evaluation of 168 vaccine series due to be marketed in Argentina (2006-2012) and subjected to official control testing in cattle, as well as repeated vaccination of cattle and other species using vaccines with high antigen concentrations, demonstrated that they did not induce antibodies to non-structural proteins (NSPs). The results show clearly that vaccines with satisfactory potency do not induce a response to NSPs, even by forcing the immune response through more concentrated doses with multiple valences and revaccination protocols at shorter irtervals than in vaccination campaigns. These results confirm that the vaccines used in routine vaccination programmes have a degree of antigen purification consistent with the needs observed on the basis of sampling for serological surveillance. Moreover, serological surveys conducted in 2006-2011 by Argentina's official Veterinary Services--the National Health and Agrifood Quality Service (SENASA)--on more than 23,000 sera per year from cattle included in the vaccination programme, in order to confirm the absence of virus circulation, revealed an average 0.05% of reactive results, consistent with the specificity of the tests. In conclusion, the vaccines produced by conventional methods and with proven potencythat are available in Argentina are sufficiently purified to ensure thatthey do not interfere with the interpretation of sampling for serological surveillance performed to support the recognition of FMD-free zones practising vaccination.

Effectiveness of systematic foot and mouth disease mass vaccination campaigns in Argentina.

The objective of this paper is to evaluate the effectiveness of systematic mass vaccination campaigns against foot and mouth disease in Argentina. The analysis was based on an estimation of the proportion of protected animals and protected farms in vaccinated populations, as reflected by levels of antibodies measured in liquid-phase enzyme-linked immunosorbent assay. The analysis was carried out in 49 animal health districts in Buenos Aires province, using data collected from four cross-sectional studies, in 2004, 2007, 2008 and 2011. Cattle were assigned to one of two categories on the basis of correlation between serological titres and expected percentage protection: non-adequately protected (expected protection < 75%) and adequately protected (expected protection ≥ 75%). The proportions of adequately protected cattle and significantly non-adequately protected farms were estimated and compared among sampled locations. Protection was variable among the districts; cattle aged one to two years showed higher levels of protection than cattle six to 12 months old, and the proportion of protected cattle was higher in the more recent studies. The results of the analysis will allow the national animal health service to investigate in depth those districts where protection was lower than the regional background protection. The authors propose that this methodology could be used to evaluate the effectiveness of vaccination campaigns in other countries or zones where systematic foot and mouth disease mass vaccination campaigns are undertaken.

Factors associated with within-herd transmission of serotype A foot-and-mouth disease virus in cattle, during the 2001 outbreak in Argentina: a protective effect of vaccination.

Argentina suffered an extensive foot-and-mouth disease (FMD) epidemic between July 2000 and January 2002, 3 months after obtaining the official FMD-free without vaccination status conferred by the World Organization for Animal Health. This is one of the largest FMD epidemics controlled by implementation of a systematic mass vaccination campaign in an FMD-free country. In 2000, 124 herds were reported as FMD positive, 2394 herds in 2001 and one in January 2002; the total number of cattle herds in the country at that time was approximately 230 000. Estimates of FMD transmission are important to understand the dynamics of disease spread and for estimating the value for the parameterization of disease transmission models, with the ultimate goals of predicting its spread, assessing and designing control strategies, conducting economic analyses and supporting the decision-making process. In this study, the within-herd coefficient of transmission, ß, was computed for herds affected in the 2001 FMD epidemic and categorized as low or high based on the median value of ß. A logistic regression model was fitted to identify factors significantly associated with high values of ß. Results suggested that the odds of having a high within-herd transmission were significantly associated with time from initial herd infection to disease detection, date of report, vaccination, and time from initial herd infection to herd vaccination. Results presented in this study demonstrate, in quantifiable terms, the protective impact of vaccination in reducing FMD transmission in infected herds. These results will be useful for the parameterization of epidemiological models aimed at quantifying the impact of vaccination and for the design and implementation of FMD emergency vaccination strategies in face of an epidemic.

[Pancreaticoduodenectomy in the era of evidence based medicine]. / La duodénopancréatectomie céphalique à l'ère de la médecine factuelle.

The aim of this comprehensive literature review was to analyse evidence based data in the field of pancreaticoduodenectomy. Pylorus preserving does reduce mortality or morbidity of the standard procedure and could increase the risk of delayed gastric emptying. Pancreaticogastrostomy does not decrease the rate of postoperative pancreatic fistula and is not superior to the pancreaticojejunal anastomosis which is more physiological. No other procedure (chemical occlusion, octreotide, stenting) has been demonstrated to prevent pancreatic fistula. Octreotide injection could be advocated in centres where there is a high rate of pancreatic fistula, when pancreatic parenchyma is soft and the main pancreatic duct thin. Intra-abdominal drainage is not beneficial and could be associated with some morbidity. Its use needs to be further evaluated. When a resection is done for pancreatic cancer, less than 5% of patients are a live five years after surgery with postoperative mortality rate of 5% in expert centres and a high morbidity rate (25-50%). Extended lymphadenectomy does not increase survival. The first trials showed that adjuvant therapies could be beneficial for pancreatic cancers, but further trials did not confirm these findings. Adjuvant therapy is not validated for pancreatic cancers and needs to be considered only in the settings of clinical trials.

Experimental toxicity of verbesina encelioides in sheep and isolation of galegine.

Verbesina encelioides is a widely distributed weed in Argentina. Although it has been suspected as poisonous, there seem to be no previous reports of its toxicity in this country. Its biological activity was evaluated through an experiment in sheep. Four 5-y-old sheep, averaging 33 kg in body weight, were given a single dose of 1.0, 3.2, 5.0 or 6.3 g of dried plant material (17.9% dry matter)/kg body weight orally in a water suspension. Forty-eight hours later, the animals given 5.0 g or 6.3 g showed dullness and lack of appetite. The higher dosed sheep became recumbent a few hours later and died 60 h after dosing without showing further signs. The other animals showed no signs. Necropsy of the dead sheep showed severe lesions in different organs: liver, kidneys, lungs, lymph nodes and digestive tract. Hydrothorax was also observed. The animal receiving 5.0 g/kg was sacrificed after 72 h to determine the degree of recovery or lesions. Microscopically, severe glomerulonephrosis and congestion in the liver, with cellular degeneration and fatty changes were observed. Additionally, hemorrhagic lymph nodes, and hemorrhagic and edematous lungs were noted. No gross nor microscopic lesions were found in the sheep receiving 5.0 g/kg. Mice injected ip with the chromatographic extract died in less than 15 min. Galegine was identified in the plant material. The minimum toxic dose of 5-6 g/kg indicates a high toxicity when compared to other poisonous plants of the southeastern area of Buenos Aires province, Argentina.

The third molar question: report of cases.

Clinical observations for the past 30 years have stimulated a strong recommendation for removal of impacted third molars at an early age.

Oral leiomyomas. Review of the literature and report of a case of palatal angioleiomyoma.

A rare case of angioleiomyoma of the palate is reported. A review of the literature shows that of a total of 116 previously reported cases of oral leiomyomas, only 19 were palatal angioleiomyomas.

Sialadenoma papilliferum.

The twelfth case of intraoral sialadenoma papilliferum is reported. The tumor appeared on the left faucial pillar of a 76-year-old white woman and is the second lesion reported to have occurred in a woman.