Zoonosis and veterinary waste disposal in rural practice.

The objectives of this study were to estimate: (a) the frequency of zoonoses in large animal veterinarians from rural areas of the province of Buenos Aires, Argentina, and (b) to describe the use and disposal of personal protective equipment (PPE) and selective veterinary clinical waste. A cross-sectional study was carried out on large animal veterinary practitioners in the Province of Buenos Aires (n=106). One third (29.2%) of them had been diagnosed with a zoonosis by laboratory-methods, being brucellosis the most frequent (22.6%). The more years passed since their graduation, the greater the chances of becoming ill (p<0.001). Gloves were the most adopted PPE; however, other elements had little or no use at all. Older and experienced professionals used PPE less frequently than young inexperienced practitioners. Some PPE was frequently reused and the final disposal of veterinary waste was often inappropriate. A change in behavior is an urgent need to preserve not only the veterinarians' health but also their families' wellbeing and to ensure proper disposal of potentially hazardous waste.

[Mycobacterium bovis in wildlife of the dairy regions of Santa Fe (Argentina)]. / Mycobacterium bovis en fauna silvestre de la cuenca lechera de Santa Fe, Argentina.

Control eradication campaigns of bovine tuberculosis based on the «test and slaughter¼ approach were successful in many countries and regions; however, in some areas the infection persists and one of the main reasons is Mycobacterium bovis infection in wild life species. Argentina has applied the same approach since 1999, achieving progress in dairy cattle herds. Nonetheless, the wildlife role has never been investigated. The objective of this study was to determine if wildlife from the Santa Fe dairy area is infected with M. bovis. Wildlife species having a positive tuberculin skin test were captured in five dairy farms. Ninety five wildlife mammals were captured; M. bovis was recovered from 7 possums (Didelphys albiventris), from one fox (Lycolapex gimnocercus) and from one rat (Rattus norvegicus). None of the animals exhibited macroscopic lesions. The most frequently isolated M. bovis spoligotypes were types 34 (4 isolates) and 12 (3 isolates). Spoligotype 34 is the most frequently isolated type in Argentine cattle. The role of D. albiventris as spillover host of M. bovis is discussed in this study.

[Knowledge of zoonoses transmission routes and of the species concerned among rural workers]. / Conocimiento de las vías de transmisión de las zoonosis y de las especies afectadas entre los trabajadores rurales.

The aim of this study was to evaluate the level of awareness of zoonoses among rural workers and their potential associations with socio-demographic factors. A cross-sectional study was performed by holding personal interviews (N=110, n=94) using a structured questionnaire. The statistical analysis included the χ(2) test, the Student's t test and Pearson and Spearman correlations. The highest level of awareness was found for trichinosis, rabies and scabies. Species transmitting brucellosis, tuberculosis and anthrax were well known, but not their modes of transmission. The least known diseases were toxocariasis and hydatidosis, followed by leptospirosis and toxoplasmosis. Significant associations were found (p<0.001) between the knowledge of transmitting species and the modes of transmission. Senior male owners, married, and living in urban areas showed the highest overall knowledge of zoonoses. Awareness of zoonoses among rural workers is inadequate. Veterinarians in conjunction with risk insurers may play a key role in providing information to people at risk.

Zoonoses in rural veterinarians in the central region of Argentina.

OBJECTIVE: To estimate the frequency of zoonoses in rural veterinarians and to search for risk factors. DESIGN: Cross-sectional study based on an anonymously answered structured questionnaire. SETTING: The interviewees participated in mandatory continuing education classes scheduled throughout the province by the College of Veterinary Surgeons. PARTICIPANTS: Overall, 741 professionals were surveyed, and 75.8% (n = 562) of them completed the structured questionnaire. MAIN OUTCOME MEASURES: Cumulative incidence (CIR) and incidence density (IDR) rates, standardised rates, χ(2) , Student's t-test, Pearson's correlation coefficient and logistic regression. RESULTS: The CIR for all zoonoses was 34.1% (brucellosis, 29.1%; toxoplasmosis, 2.1%; leptospirosis, 0.6%; tuberculosis, 0.6%; anthrax, 0.6%; ringworm, 0.4%; other, 0.6%). The IDR for the period 1964-2008 was estimated to be 20.7% (19.5% for brucellosis). The brucellosis IDR decreased between 1964 and 2008 and was higher during early post-graduation. The risk of brucellosis was associated with the number of years of practice and the geographical area. Sixty-nine respondents had at least one day of absence from work (24.0 ± 27.8 days). CONCLUSIONS: A high frequency of zoonoses was reported by veterinarians with a large animal practice. Although the rate of zoonoses may be decreasing, further studies are needed to confirm this finding. A joint effort of all institutions is needed to prevent zoonoses among private practitioners.

[Epidemiology of hemolytic uremic syndrome in two regions of Buenos Aires Province]. / Epidemiología del síndrome urémico hemolítico en dos regiones de la Provincia de Buenos Aires.

The objectives of this study were (a) to describe and estimate the frequency of hemolytic uremic syndrome (HUS) in rural and urban populations in two regions of Buenos Aires Province, and (b) to compare the presentation and distribution of factors hypothetically associated with HUS. A total of 82 HUS cases, recorded during the years 2005-2010 in rural and urban areas of the south-central region of Buenos Aires Province, were clinically and epidemiologically characterized. Statistical data analysis included Chi square or Fisher test and median test. The incidence rate of HUS was significantly higher in the rural population, being 12.7 cases per 100 000 (CI 0-23.5) in rural inhabitants vs. 7.1 cases per 100 000 (CI 0-9.5) in urban inhabitants. The median age of the patients was 27 months (5-139 months), significantly lower in children from the rural area. This could be explained by a more frequent contact with bovine feces, the consumption of raw milk and a higher proportion of relatives who work in risk labors found in the rural population. Although HUS is often associated with the consumption of undercooked minced meat, most of the children cases here included did not present this antecedent. Clinical manifestations were similar in both subpopulations. One-third of urban patients had received antibiotics prior to HUS development.

Detection of Mycobacterium bovis-infected dairy herds using PCR in bulk tank milk samples.

Bovine tuberculosis (bTB) is a chronic and zoonotic disease due to Mycobacterium bovis. The tuberculosis eradication campaign carried out in Argentina has considerably improved the health situation of the herds. Here we evaluated a strategy to detect M. bovis-infected herds by Touch-Down IS6110 polymerase chain reaction (PCR) in bulk tank raw milk from dairy farms. We evaluated 177 samples from herds with the official tuberculosis free certificate (TFC) and 80 from herds without the certificate, non-tuberculosis-free certificate (NTFC), from 10 departments of Santa Fe province, Argentina. To avoid the effect of Taq polymerase inhibitors, a dilution of DNA template was performed. Positive PCR results were obtained in 102 (40%) of the samples, whereas negative ones were obtained in 155 (60%) of the samples. Importantly, 44% of NTFC and 38% of TFC samples were positive. All samples were subjected to culture in Löwenstein Jensen and Stonebrink media with no positive isolation. The negative predictive value (NPV) of PCR in the TFC group was 95%, while the positive predictive value (PPV) of PCR in the NTFC group was 51%. Based on these results, this work proposes a method that should be applied regularly to detect M. bovis--infected dairy herds, complementary to the official test of tuberculin, or purifed protein derivative (PPD), to control dairy herds, especially those free of tuberculosis.

[Human leptospirosis diagnosis:macroscopic agglutination test evaluation in different stages of the disease]. / Diagnóstico de leptospirosis humana: evaluación de la aglutinación macroscópica en diferentes etapas de la enfermedad.

OBJECTIVE: To evaluate the macroscopic agglutination test using Temperature Resistant (TR) antigen as a screening test for the diagnosis of human leptospirosis in different stages of the disease. MATERIALS AND METHODS: The criteria for case definition were based on the results of the microscopic agglutination test (MAT), leukocyte counts and neutrophilia, resulting 218 confirmed cases and 242 non- cases. Each sample was classified according to the days of the disease progression in three stages: first (<10 days), second (10 - 25 days) and third (> 25 days). The design was cross-sectional observational. RESULTS: TR sensitivity was 71,1% on stage 1. 93.4% on stage 2 and 95.6% on stage 3. The specificity at different stages ranged from 79.0 to 69.2%. Intra and inter-operator variability was moderate. CONCLUSION: TR variability, low sensitivity in the first stage and low specificity found in all stages of the disease, suggest that it is essential to incorporate new diagnostic methods to screen for early detection of cases in our country and in countries that still apply such methods.

Factors associated with sporadic verotoxigenic Escherichia coli infection in children with diarrhea from the Central Eastern Area of Argentina.

Verotoxigenic Escherichia coli (VTEC) are one of the most important emerging foodborne pathogens and the principal cause of hemolytic uremic syndrome (HUS). This entity has been recognized worldwide as a priority issue in the field of zoonoses and public health, and Argentina is the country with the highest incidence of HUS in children less than 5 years of age.The lack of specific treatment, combined with the high morbidity rate of VTEC infection, makes prevention the main tool for reducing the incidence of HUS. The current work aimed at assessing the factors associated with sporadic VTEC infection in children with acute diarrhea from the Central Eastern area of Argentina where the incidence rate of HUS in children under 5 is the highest worldwide. A univariate analysis was performed to identify potential factors associated with VTEC infection by calculating odds ratios (OR) with 95% confidence intervals (CI). Then, a multivariate logistic regression model was performed. Interaction and association between significant factors were checked. "Recent consumption of food prepared outside home" (OR: 2.4, 95% CI 1.05-5.7) and "recent vegetables consumption" (OR=0.4; 0.2-0.8) were identified as independent factors associated with VTEC infection. We believe that the data obtained from this study further the current knowledge about the epidemiology of VTEC infection in Argentina and could be considered when planning strategies for the prevention of the disease.

[Verotoxin-producing Escherichia coli: quantitative model of exposure and risk scenarios in cattle carcasses in Argentina]. / Escherichia coli verotoxigénica: modelo cuantitativo de exposición y escenarios de riesgos en canales bovinas en Argentina.

OBJECTIVES: Quantify contamination by verotoxin-producing Escherichia coli associated with hemolytic uremic syndrome (VTEC-HUS) in cattle carcasses and generate estimates of exposure in three likely scenarios. METHODS: A model was constructed of the frequency and magnitude of VTEC-HUS contamination from primary production to the removal of the carcasses from cold storage, based on the published scientific information, epidemiological data, and information from local experts. The probability distributions that best described each step in the process and scenarios were input to the @Risk program with multiple simulations using Monte Carlo analysis. Pearson s correlation test was used for the sensitivity analysis. RESULTS: The estimated frequency of carcasses with VTEC-HUS was 0.37 (95% CI: 0.26 to 0.58) and the final load of VTEC-HUS was 0.47 log CFU/carcass (95% CI: -2.46 to 3.62). The most closely related variables were the fattening system (r = -0.681) and the theoretical concentration of VTEC-HUS on the cattle's skin (r = 0.702). Vaccinating the animals reduced the frequency of VTEC-HUS in the carcasses by 54.1%, although there were no significant changes in the final VTEC-HUS load. Washing the carcasses reduced the final load by 0.42 log CFU/carcass compared with the baseline model, without any change in the frequency. A 50%-60% increase in the percentage of animals fattened in pens would increase the frequency of carcasses contaminated with VTEC-HUS by 15%-23%. CONCLUSIONS: Vaccinating the animals was the most effective scenario for reducing introduction of the bacteria in the beef production chain. Intensifying livestock production will increase the public health risk due to greater exposure to VTEC-HUS.

Epitope mapping of pathogenic Leptospira LipL32.

AIMS: To identify LipL32 epitopes and to evaluate their capability to recognize specific antibodies using ELISA. METHODS AND RESULTS: Epitope mapping by means of a library of overlapping peptide fragments prepared by simultaneous and parallel solid phase peptide synthesis on derivatized cellulose membranes (SPOT synthesis) was carried out. Eighty-seven overlapping decapentapeptides corresponding to the complete sequence of LipL32 were synthesized. According to spot-image intensities, the most reactive sequences were localized in regions 151-177 (sequence AAKAKPVQKLDDDDDGDDTYKEERHNK) and 181-204 (sequence LTRIKIPNPPKSFDDLKNIDTKKL). Two peptides (P1 and P2) corresponding to these sequences were synthesized, and their reactivity evaluated using ELISA test. CONCLUSIONS: Epitope identification and analysis suggested the existence of two antigenic regions within LipL32. These LipL32 reactive regions were highly conserved among antigenically variants of Leptospira spp. isolates. Peptides containing these regions (P1 and P2) showed a good capability for anti-leptospiral antibody recognition. SIGNIFICANCE AND IMPACT OF THE STUDY: This finding could have potential relevance not only for serodiagnosis but also as a starting point for the characterization of targets for vaccine design.