Evaluation of a data-driven youngstock rearing quality system in Dutch dairy herds (2019-2022).

In recent years, the Netherlands exhibited an increased focus on improving youngstock rearing. Several data-driven tools were developed to assess and benchmark calf rearing practices based on key indicators, stimulate farmers to improve their youngstock rearing and reduce calf mortality. KalfOK is such a data-driven tool in which a farm-level overview with 15 indicators of youngstock rearing quality is communicated to participating farmers. In this study we assessed which farm characteristics are associated with A) a continuously high or low KalfOK score and B) frequent usage of KalfOK. Data from KalfOK and the identification and registration system were available for all participating herds over a period between 2019 and 2022 (Dataset A). Additionally, a sample of 324 dairy farmers, randomly selected from the entire Dutch dairy population (Dataset B), participated in a voluntary survey. Multivariable (logistic) regression models were used to A) identify differences in characteristics between farms with a continuously high- and farms with a continuously low KalfOK score and B) assess which farm characteristics were associated with frequent use of the KalfOK report. The results of analysis A showed multiple factors associated with having a low or high KalfOK score, including replacement rate, closed farming system, limited growth in herd size and the region where a farm was located. Sociological factors might also partly explain the difference between high and low scoring farms. Analysis B showed that approximately half of the surveyed farmers indicated that they do not frequently use their KalfOK overview in their calf rearing management. The KalfOK score of farmers who regularly use their KalfOK report was higher - and consequently better - compared to the KalfOK score of farmers who sometimes or never use KalfOK. Additionally, farmers using a milk robot and those discussing KalfOK regularly with their veterinarian, used KalfOK more often. Thirty four percent of the surveyed farmers made adjustments to their youngstock rearing management since the start of participation. The study's insights into patterns in KalfOK utilization and associations with farm characteristics provide valuable information for ongoing efforts to enhance calf rearing practices via the use of KalfOK. It is important to consider what is needed to convince farmers that do not use the KalfOK tool to frequently start using their KalfOK report. Future research incorporating sociological aspects can provide a more comprehensive understanding of other dynamics influencing calf rearing and contribute valuable insights for enhancing the effectiveness of programs like KalfOK in promoting calf health and welfare.

Bovine leukemia virus transmission rates in persistent lymphocytotic infected dairy cows.

Bovine leukemia virus (BLV) establishes a lifelong persistent infection in dairy cattle. White blood cell count (WBC) is correlated with proviral load in the blood and milk of BLV-infected cattle, and testing WBC can be used to assess both BLV infectiousness levels and risk of BLV transmission from different types of infected animals. The objective of the study was to compare effective transmission rates (ß) and the basic reproduction ratio (R o) among two types of BLV-infected dairy cows in Chile: those affected with persistent lymphocytosis (PL) vs. aleukemic (AL).The estimated (ß) coefficient was higher in PL cattle [1.1; 95% Confidence interval (CI) (-1.6, 3.8)], compared to AL cattle (-3.1; 95% CI = -3.7, -2.5). In addition, the R o was higher in PL cattle (60.4; 95% CI = 3.5; 820.6), compared to AL cattle (1.5; 95% CI = 0.7, 3.1). The ratio between PL/AL expected rate of cases was 73.9. The estimated effective transmission rate and the Ro were higher in PL cattle compared to AL cattle. The WBC test is a convenient alternative that can be considered for risk identification and risk management of BLV infection in dairy herds; particularly in livestock regions where laboratory capacity is limited (e.g., use of PCR or gene sequencing techniques) and/or molecular tests are not cost-effective. Therefore, when prevalence of infection is high, the removal of PL cattle should be engaged to control BLV within-herds.

Incidence and recurrence of bovine abortion in dairy cattle from Costa Rica.

The reproductive efficiency and milk yield of cows are crucial factors in a dairy farm's profitability. However, abortions can have a negative impact on these factors. While the morbidity of abortion has been estimated in many countries, information on the burden on dairy cattle in tropical conditions is limited, and Costa Rica is a good example. This study aims to assess the incidence and recurrence of bovine abortion in dairy cattle from Costa Rica. The study analysed the morbidity of abortion in Costa Rican dairy herds between 2010 and 2022. The incidence rate (IR) and the recurrence rate (ReR) were calculated per 100 cow-months at risk using data from the Veterinary Automated Management and Production Control Programme (VAMPP). The dataset comprised 1032,457 lactations from 330,265 cows in 1134 specialized dairy herds. Abortions were classified either as early foetal mortality (EFM) or late foetal mortality (LFM). Rates were estimated based on cow breed, lactation number, and ecological zone to which the farm belongs. The IR of general abortion, EFM, and LFM cases were 0.98, 0.41, and 0.57 per 100 cow-months at risk, respectively. No statistically significant differences were found in the IR between cow breed, lactation number, and ecological zone, nor for the trend of abortions over calving years. The first ReR (for cows that had one previous abortion during the lactation) was 0.95, and the second ReR (for cows that had two previous abortions during the lactation) was 1.41 per 100 cow-months at risk. These results suggest that bovine abortions are an important ongoing problem in dairy farms in Costa Rica with potentially detrimental effects on the reproductive and productive performance of cows and may be representative of other specialized tropical dairy systems in Latin America.

Bridging Food Systems and One Health: A key to preventing future pandemics?

Food Systems and One Health are two approaches increasingly known for the holistic perspective they bring when addressing the issues that concern them: food and health. This systematic literature review aims to explore the evidence for using these approaches in a concerted manner to better manage zoonoses. By zoonoses management, we refer to improving the ability to address current zoonoses as well as preventing future ones. A total of 98 scientific articles were screened, of which 29 were considered eligible due to their focus on operationalizing each approach to help address zoonoses, as well as a combination of the two. Most articles implement One Health to prevent zoonoses by guiding stakeholders in concerted and participatory decision-making processes. However, the One Health approach can also be adopted via data modelling. Several articles refer to the monitoring and evaluation process of One Health initiatives to prevent zoonoses and discuss best practices to successfully implement the approach. Contrastingly, only three studies adopt a Food System approach to manage zoonoses, despite the profound connections existing between our food systems and the emergence of zoonotic risks. We conclude that there is a lack of integration between the One Health and Food System approaches to manage zoonoses. We also show that experts call for integration, so that not only human, animal, plant, and environmental health are considered, but also the socio-economic trade-offs when monitoring and developing strategies to manage zoonoses. This can be reversed, enabling zoonotic risks to be addressed when planning for our food systems of tomorrow.

Seroprevalence of pathogenic Leptospira serogroups in asymptomatic domestic dogs and cats: systematic review and meta-analysis.

Leptospirosis is a neglected zoonotic disease transmitted by contact with the urine of animals infected with pathogenic species of the bacteria Leptospira or by contact with environments contaminated with the bacteria. Domestic dogs and cats may act as reservoirs or as sentinels of environmental contamination with leptospires, posing a public health concern. There is a great diversity of leptospires, and one common way to classify them is into serogroups that provide some information on the host species they are associated with. The aims of this study were: (1) to quantitatively summarize the overall prevalence and serogroup-specific prevalence of antibodies against pathogenic leptospires in asymptomatic dogs and cats and (2) to identify environmental and host characteristics that may affect the prevalence. Three electronic databases and the reference lists of eligible articles were screened, for epidemiological studies conducted between the years 2012-2022. We estimated overall and serogroup-specific prevalence using three-level meta-analysis models and assessed potential sources of heterogeneity by moderator analysis and meta-regression. Eighty-four studies met the inclusion criteria (dog studies 66.7%, cat studies 26.2%, and both species 7.1%). There were significant differences between dogs and cats in the overall prevalence model (P < 0.001), but not in the serogroup-specific model (P>0.05). In dogs, the prevalence of Leptospira interrogans serogroup Canicola was significantly higher than the other pathogenic serogroups (P < 0.001), while in cats there were no significant differences among serogroups (P = 0.373). Moderator analysis showed that the prevalence of L. kirschneri serogroup Grippotyphosa was significantly higher in stray/sheltered dogs than in domiciled dogs (P = 0.028). These results suggest that pathogenic serogroups associated with small mammals are circulating among asymptomatic pets and should be taken into account in the transmission cycle of leptospires, as well as in the standard MAT panel for diagnosis in dogs and cats. It also highlights the importance of including both dogs and cats as potential reservoirs when conducting eco-epidemiological studies in different geographical and ecological areas.

Genetic diversity of Bartonella rpoB haplotypes in domestic cats from Chile.

The study aimed to determine the inter and intra-host Bartonella spp. genetic diversity in cats from Chile. 'Seventy-nine cats' blood DNA samples qPCR Bartonella spp. positive were subjected to T-A cloning of Bartonella spp. rpoB partial gene (825 bp), and sequencing by Sanger method. The sequences were submitted to phylogenetic and polymorphism analysis. Thirty-six (45.6%) samples were successfully cloned, generating 118 clones of which 109 showed 99.6%-100% identity with Bartonella henselae whereas 9 showed 99.8-100% identity with Bartonella koehlerae. Haplotype analysis yielded 29 different rpoB-B. henselae haplotypes, one (hap#2) overrepresented in 31 out of 33 cats, and 4 rpoB-B. koehlerae haplotypes, with hap#2 represented in all 3 B. koehlerae infected cats. More than one rpoB -B. henselae and B. koehlerae haplotypes were identified in individual cats, reporting by first time coinfection by different B. henselae/B. koehlerae rpoB variants in cats from Chile.

Draft genomes of 16 Bartonella henselae strains from cats in Valdivia, Chile.

Bartonella henselae is a primary zoonotic agent, having cats as asymptomatic reservoirs. In humans, it causes cat scratch disease. Here, we report the whole genome sequences of 16 strains isolated from cats in Valdivia city, Southern Chile. Strains showed little variability in the multilocus sequence typing profiles.

Uso de barreras primarias en función del ángulo del gantry en búnker de radioterapia / Uso de barreiras primárias em função do ângulo do gantry em bunkers de radioterapia / Use of primary barriers as a function of gantry angle in radiotherapy bunker

Introducción: el diseño de los búnkeres de radioterapia es de vital importancia no solo por la seguridad radiológica, sino también por el costo que implican. Los cálculos de blindaje de las paredes primarias de los búnkeres de los aceleradores lineales de radioterapia se determinan a partir del factor de uso de estas paredes. Los documentos internacionales como el NCRP 151 utilizan para el cálculo de estas barreras un factor de uso igual a 0.25. Objetivo: estudiar la distribución del uso de las barreras primarias en función de los tratamientos realizados buscando contrastar la homogeneidad en el uso de las barreras. Material y Métodos: con los datos de pacientes realizados durante un año (2021) en dos aceleradores lineales, uno dual y otro monoenergético, se generó una base de datos con la que se calculó la frecuencia de uso de las paredes primarias. En el presente trabajo se evalúa la diferencia entre el uso dado de las barreras y las estimaciones de uso internacional. Resultados: se encuentra que en el acelerador dual en la energía de 15X los campos más usados tienen ángulos de gantry 0º, 90º, 180º, 270º, teniendo un peso acumulado aproximado al 65% al igual que la carga de trabajo para esos ángulos, esto implica que los ángulos diferentes a estos tienen un uso muy inferior al previsto por el cálculo inicial. En el acelerador dual en la energía de 6X el campo más usado es a 0º teniendo un peso aproximado al 14%, pero la carga de trabajo a 0º no se diferencia apreciablemente del resto de los ángulos ya que la distribución no tiene direcciones preferenciales, ninguno de los valores llega a 10% que concuerda con el uso homogéneo de la barrera. En el acelerador monoenergético el peso relativo de los ángulos de 90º y 270º en el uso de las barreras es aproximadamente 34% para cada una, superior al 25% estimado inicialmente. Conclusiones: las barreras primarias de los búnkeres de radioterapia tienen espesores marcados por el cálculo de blindaje, los cuales se pueden hacer basados en documentos internacionales que son referencia del tema. Se considera en las referencias para la barrera primaria un factor de uso igual para las mismas, sin embargo en la práctica clínica se pueden tener un factor de uso no uniforme respondiendo a los tipos de tratamientos que se designen realizar en el equipo. Esta realidad abre la puerta para plantear blindajes optimizados que podrían generar búnkeres más económicos y mejor utilización del espacio de acuerdo a las condiciones dadas para cada caso en particular.

Introduction: The design of radiotherapy bunkers is of vital importance not only for radiation safety, but also for the cost involved. The shielding calculations of the primary walls of radiotherapy linear accelerator bunkers are determined from the use factor of these walls. International documents such as NCRP 151 use for the calculation of these barriers a usage factor equal to 0.25. Objective: to study the distribution of the use of primary barriers according to the treatments performed, seeking to contrast the homogeneity in the use of the barriers. Material and Methods: with the data of patients performed during one year (2021) in two linear accelerators, one dual and the other monoenergetic, a database was generated with which the frequency of use of the primary walls was calculated. The present work evaluates the difference between the given use of the barriers and the estimates of international use. Results: it is found that in the dual accelerator at 15X energy the most used fields have gantry angles 0º, 90º, 180º, 270º, having an accumulated weight of approximately 65% as well as the workload for those angles, this implies that the angles different from these have a use much lower than the one foreseen by the initial calculation. In the dual accelerator at 6X energy the most used field is at 0º having an approximate weight of 14%, but the workload at 0º is not appreciably different from the rest of the angles since the distribution does not have preferential directions, none of the values reaches 10% which is consistent with the homogeneous use of the barrier. In the monoenergetic accelerator, the relative weight of the 90º and 270º angles in the use of the barriers is approximately 34% for each one, higher than the 25% initially estimated. Conclusions: the primary barriers of radiotherapy bunkers have thicknesses marked by the shielding calculation, which can be made based on international documents that are a reference on the subject. It is considered in the references for the primary barrier an equal use factor for them, however in clinical practice they can have a non-uniform use factor responding to the types of treatments that are designed to be performed in the equipment. This reality opens the door to propose optimized shielding that could generate more economical bunkers and better use of space according to the conditions given for each particular case.

Introdução: O projeto de bunkers de radioterapia é de vital importância não apenas para a segurança da radiação, mas também para o custo envolvido. Os cálculos de blindagem para as paredes primárias dos bunkers de aceleradores lineares de radioterapia são determinados com base no fator de uso dessas paredes. Documentos internacionais, como o NCRP 151, usam um fator de uso igual a 0,25 para o cálculo dessas barreiras. Objetivo: estudar a distribuição do uso de barreiras primárias de acordo com os tratamentos realizados, buscando contrastar a homogeneidade no uso das barreiras. Material e métodos: com os dados de pacientes tratados durante um ano (2021) em dois aceleradores lineares, um dual e outro monoenergético, foi gerado um banco de dados com o qual foi calculada a frequência de uso das paredes primárias. Este artigo avalia a diferença entre o uso determinado de barreiras e as estimativas internacionais de uso. Resultados: verifica-se que no acelerador duplo com energia de 15X os campos mais utilizados são os ângulos de pórtico 0º, 90º, 180º, 270º, com um peso acumulado de aproximadamente 65%, assim como a carga de trabalho para esses ângulos, o que implica que os ângulos diferentes desses têm um uso muito menor do que o previsto pelo cálculo inicial. No acelerador duplo a 6X de energia, o campo mais utilizado é o de 0º com um peso aproximado de 14%, mas a carga de trabalho em 0º não é sensivelmente diferente do resto dos ângulos, já que a distribuição não tem direções preferenciais, nenhum dos valores chega a 10%, o que é consistente com o uso homogêneo da barreira. No acelerador de monoenergia, o peso relativo dos ângulos de 90º e 270º no uso das barreiras é de aproximadamente 34% para cada um, superior aos 25% estimados inicialmente. Conclusões: as barreiras primárias dos bunkers de radioterapia têm espessuras balizadas pelo cálculo de blindagem, que pode ser feito com base em documentos internacionais que são referência no assunto. As referências para a barreira primária consideram um fator de uso igual para elas, mas na prática clínica elas podem ter um fator de uso não uniforme, dependendo do tipo de tratamento que o equipamento foi projetado para realizar. Essa realidade abre as portas para uma blindagem otimizada que poderia gerar bunkers mais econômicos e melhor uso do espaço de acordo com as condições dadas para cada caso específico.

Urine shedding patterns of pathogenic Leptospira spp. in dairy cows.

Pathogenic Leptospira spp. are zoonotic bacteria that infect wild and domestic animals. Humans contract leptospirosis directly through contact with infected animals or indirectly from contaminated water or soil. In mammalian reservoirs, the pathogen can colonize renal tubules for lengthy periods and persistently contaminate the environment through urine. Cattle have been reported to shed several serovars; with Hardjo the most common serovar found in cattle. Without clinical manifestations, the infection can spread within a herd, impairing productivity, and putting workers like farmers, abattoir operators and veterinarians at risk. The dynamics of pathogenic Leptospira shedding was studied in six dairy herds in southern Chile. Various intermittent urine shedding patterns were found, with elimination periods between 79 and 259 days and bacterial loads ranging from 3 × 104 to 4.4 × 104 bacteria/mL. The current study was the first to assess the various urine shedding patterns and loads of pathogenic leptospires shed through urine of naturally-infected dairy cows. In addition, the study suggests that vaccination does not prevent cattle infection, although it influences loads of pathogenic leptospires excreted in urine. Our study provides a great awareness of asymptomatic animal carriers in an endemic area and will contribute to improving disease control and designing better prevention strategies.

Bartonella spp. in households with cats: Risk factors for infection in cats and human exposure.

The aim of this study was to estimate the occurrence of Bartonella spp. per household in cats and the risk factors for Bartonella spp. positivity in cats and their owners from Valdivia, Chile. A total of 464 cats (distributed within 324 households) and 326 humans (control group [n = 112] and cat owner [n = 214]) distributed in 262 households were sampled. From the cat owners (n = 214), 128 humans were in households where the cat was also sampled, totaling 84 households with dual sampling. Real-time PCR (qPCR) was used for Bartonella spp. detection in blood from cats and humans, and immunofluorescent immunoassay (IFA) anti-Bartonella henselae was performed in human serum samples. Out of the total of 324 households, 20.43% presented at least one Bartonella positive cat. From the households with dual sampling, 29.7% (25/84) presented at least one qPCR-Bartonella spp. positive cat. However, Bartonella DNA was not amplified in humans, and in 7.3% (6/82) of the households was found at least one of the cat's owners exposed to B. henselae. Cats younger than one year (Odds Ratio (OR) = 5.3), non-neutered (OR 3.46), sampled at home (OR 5.82), and with improper application of tick/flea control products (OR 3.13) showed a higher risk for Bartonella spp. presence. Humans with occupational exposure involving animal contact, were more likely to exhibit B. henselae seropositivity (OR 7.5). Bartonella spp. was present in the cats a moderate number of households, but Bartonella DNA was not detected in owners' blood, inferring that there is a low risk of recent human infection in the studied population.

Diagnostic accuracy of an immunomagnetic separation-PCR assay to detect pathogenic Leptospira spp. in urine from dairy cattle, using a Bayesian latent class model.

Leptospirosis is a zoonotic disease that has spread worldwide and causes significant economic losses in the dairy industry. The causal agents of this infectious disease are members of the genus Leptospira, known as pathogenic Leptospira spp. Specific clinical signs of the infection are difficult to detect. Therefore, the disease is normally under-diagnosed, mostly due to the lack of a cost-effective technique for diagnosing animals with a low bacterial load in their urine. The aim of this study was to assess the diagnostic accuracy of a qPCR coupled with a previous Immunomagnetic separation (IMS) step (IMS-qPCR) against a qPCR without using IMS, using a Bayesian latent class model (2 tests, 3 populations) to determine the leptospirosis infectious status in naturally infected dairy cattle. The results revealed that IMS qPCR had a sensitivity (Se) of 95.7% (95% Probability Interval (PI) = 85.0; 99.4%) and a specificity (Sp) of 98% (95% PI = 96.1; 99.4%), indicating that it is more sensitive than conventional qPCR (Se = 69.7% (95% PI = 59.2; 79.0%); median difference = 25.2% (Monte Carlo Error = 10.2%); and the Sp = 98.8% (95% PI = 97.6; 99.5%), median difference = 0.8% (Monte Carlo Error = 2.1%). Therefore, results shows that IMS-qPCR is a more useful diagnostic tool in terms of accuracy for detecting infectious animals with pathogenic Leptospira in their urine.

Green AOT reverse micelles as nanoreactors for alkaline phosphatase. The hydrogen bond "dances" between water and the enzyme, the reaction product, and the reverse micelles interface.

In this work, we present an investigation of the influence of water encapsulated in 1,4-bis-2-ethylhexylsulfosuccinate/methyl laurate and 1,4-bis-2-ethylhexylsulfosuccinate/isopropyl myristate reverse micelles on the enzymatic hydrolysis of 1-naphthyl phosphate by alkaline phosphatase. Our results show that the enzyme is active in the biocompatible reverse micelles studied and that the Michaelis-Menten kinetic model is valid in all systems. We found that both micellar systems studied have a particular behavior toward pH and that the penetration of external solvents into the interfaces is crucial to understanding the effect. Methyl laurate does not disrupt the interface and is not necessary to control the pH value since alkaline phosphatase in the center of the micelles is always solvated similarly. In contrast, isopropyl myristate disrupts the interfaces so that the water and 1-naphthol molecules cannot form hydrogen bond interactions with the polar head of the surfactant. Then, when the water is at pH = 7, the 1-naphthol moves away to the interfaces inhibiting alkaline phosphatase which is not observable when the water is at pH = 10. Our study shows that the concept of pH cannot be used directly in a confined environment. In addition, our research is of great importance in the field of reactions that occur in reverse micelles, catalyzed by enzymes.

Bartonella spp. and Typhus Group Rickettsiae among Persons Experiencing Homelessness, São Paulo, Brazil.

Persons experiencing homelessness in São Paulo, Brazil, were seropositive for Bartonella spp. (79/109, 72.5%) and typhus group rickettsiae (40/109, 36.7%). Bartonella quintana DNA was detected in 17.1% (14/82) body louse pools and 0.9% (1/114) blood samples. Clinicians should consider vectorborne agents as potential causes of febrile syndromes in this population.

A safe and effective vaccine against bovine leukemia virus.

Previous attempts to develop a vaccine against bovine leukemia virus (BLV) have not been successful because of inadequate or short-lived stimulation of all immunity components. In this study, we designed an approach based on an attenuated BLV provirus by deleting genes dispensable for infectivity but required for efficient replication. The ability of the vaccine to protect from natural BLV infection was investigated in the context of dairy productive conditions in an endemic region. The attenuated vaccine was tested in a farm in which the prevalence rose from 16.7% in young cattle at the beginning of the study to more than 90% in adult individuals. Sterilizing immunity was obtained in 28 out of 29 vaccinated heifers over a period of 48 months, demonstrating the effectiveness of the vaccine. As indicated by the antiviral antibody titers, the humoral response was slightly reduced compared to wild-type infection. After initial post-vaccination bursts, the proviral loads of the attenuated vaccine remained most frequently undetectable. During the first dairy cycle, proviral DNA was not detected by nested-PCR in milk samples from vaccinated cows. During the second dairy cycle, provirus was sporadically detected in milk of two vaccinated cows. Forty-two calves born from vaccinated cows were negative for proviral DNA but had antiviral antibodies in their peripheral blood. The attenuated strain was not transmitted to sentinels, further supporting the safety of the vaccine. Altogether, these data thus demonstrate that the vaccine against BLV is safe and effective in herd conditions characterized by a very high incidence. This cost-effective approach will thus decrease the prevalence of BLV without modification of production practices. After facing a series of challenges pertaining to effectiveness and biosafety, the vaccine is now available for further large-scale delivery. The different challenges and hurdles that were bypassed may be informative for the development of a vaccine against HTLV-1.

Seroprevalence of pathogenic Leptospira spp. in domestic dogs from southern Chile and risk factors associated with different environments.

Leptospirosis is a neglected and severe zoonotic bacterial disease that affects canine populations worldwide, and it is present in animals from different settings, such as urban and rural environments. Therefore, a cross-sectional study was conducted on owned domestic dogs from urban and rural origins in southern Chile. The study aimed: 1) to estimate the true prevalence of pathogenic Leptospira in dogs from urban and rural environments in southern Chile, 2) to determine the serovars circulating in an endemic area of Chile, 3) to assess potential risk factors associated with seropositivity in dogs from urban and rural environments. Blood samples from 706 canines were collected, and the serum was tested with Micro-Agglutination-Test (MAT), using a panel of 13 serovars. A Bayesian approach was applied to estimate True prevalence (TP). In addition, dog owners answered a questionnaire that had prompts regarding dog characteristics and potential risk factors. The effect of these factors on the risk of being infected was analysed using a logistic regression model. The TP for urban dogs was 9.4% and 9.1% for rural animals. However, seroprevalence was higher in dogs with different individual, lifestyle, and habitat characteristics regarding their origin. For example, in urban animals, those living in places with rodents roaming near houses and dogs with rodent hunting habits had decreased risk for the seropositivity in MAT. On the other hand, in rural dogs, those of a recognized breed, with contact with cattle and sheep, living with more than one cat at home and living in places close to natural water sources have more risk to seropositivity in MAT. The presence of anti-Leptospira antibodies is widespread in pet dogs in urban and rural environments in southern Chile, and individual, lifestyle and habitat characteristics of the animals, according to the origin, are associated with the seropositivity in MAT. Therefore, the adoption of preventive measures is urgent, in addition to increase the awareness either in public health institutions, practitioners and companion animals' owners, considering the zoonotic potential of Leptospira infection and the close contact between people and their pets.

Assessment of Natural Transmission of Bovine Leukemia Virus in Dairies from Southern Chile.

Bovine leukemia virus (BLV) is a retrovirus that affects cattle worldwide. A longitudinal study was conducted with the aim to (a) estimate the incidence rate of the BLV infection of dairy farms in the regions of Los Ríos and Los Lagos (Chile), and (b) describe the frequency and epidemiological association of risk management practices related to new cases in cattle on dairy farms in Southern Chile. Infection status was based on commercial blocking ELISA results, on serum and milk. Individual information on animals and management practices was extracted from farm records, and then the most likely date of infection for new cases was estimated. The number of new infections was used to calculate the within-herd incidence rate. Adult animals had an incidence rate of 1.16 (95% CI 0.96; 1.20) cases per 100 cow-months at risk, while for young animals it was 0.64 (95% CI 0.44; 1.00) cases per 100 animal-months at risk. Rectal palpation, artificial insemination, and injections were the most common practices related to infection. Further studies are needed to determine if these are the only practices that facilitate spreading or if there are other practices that can be handled better in order to reduce the spread of BLV.

Speciation and Proton Conductivity of Phosphoric Acid Confined in Mesoporous Silica.

Phosphoric acid (PA) confined in a commercial mesoporous silica (CARIACT G) with porous size in the range of 3 to 10 nm was studied in relation to its coordination with the silanol groups on the silica surface as a function of temperature, up to 180 °C, using 31P and 29Si MAS NMR spectroscopy. As the temperature increases, the coordination of Si and P in the mesopores depends on the pore size, that is, on the area/volume ratio of the silica matrix. In the mesoporous silica with the higher pore size (10 nm), a considerable fraction of PA is nonbonded to the silanol groups on the surface, and it seems to be responsible for its higher conductivity at temperatures above 120 °C as compared to the samples with a smaller pore size. The electrical conductivity of the functionalized mesoporous silica was higher than that reported for other silico-phosphoric composites synthesized by sol-gel methods using soft templates, which require high-temperature calcination and high-cost reagents and are close to that of the best PA-doped polybenzimidazole membranes used in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). The rate of PA release from the mesoporous silica matrix when the system is exposed to water has been measured, and it was found to be strongly dependent on the pore size. The low cost and simplicity of the PA-functionalized mesoporous silica preparation method makes this material a promising candidate to be used as an electrolyte in HT-PEMFCs.

Network analysis of cattle movements in Chile: Implications for pathogen spread and control.

Livestock movement between herds is one of the main routes for a pathogen to spread between herds. Understanding the contact structure, patterns and importance of specific individuals and classes can help assess dissemination risk, control, and surveillance measures. In this study, the cattle herd's contact structure in southern Chile was characterized based on the study of movement within one of the most important geographical regions for livestock production. Using Social Network Analysis, network measures of centrality, network cohesion and contact chains were estimated to identify essential features that can influence disease transmission among premises. Static and disaggregated by season networks were built for the entire set of nodes and for the Los Rios region animal flow only. For all networks, it was found that most nodes had a few movements; meanwhile, a small number of them were highly connected. Livestock markets have a powerful influence over the networks, being the most connected and central nodes, appearing as candidates for surveillance because of their possible role as super spreaders. Nodes attributes were associated with the likelihood of having high contact chains measures, such as herd class, location, and presence of markets anywhere on the contact chain. This work is the first deep analysis in livestock flows in Chile and shows the importance of animal movement data interpretation to assess pathogen risk spread in the country.

Assessment of the Current Surveillance System for Human Leptospirosis in Ecuador by Decision Analytic Modeling.

Leptospirosis is a globally disseminated zoonotic disease with no national surveillance systems. On the other hand, surveillance is crucial for improving population health, and surveillance systems produce data that motivates action. Unfortunately, like many other countries, Ecuador put in place a monitoring system that has never been tested. The goal of this study was to use scenario tree modeling to assess the sensitivity of Ecuador's current national surveillance system to human leptospirosis as the basis for an economic assessment of the system. We created a decision-tree model to analyze the current system's sensitivity. The inputs were described as probabilities distributions, and the model assessed the program's sensitivity as an output. The model also considers the geographical and weather variations across Ecuador's three continental regions: Andean, Amazonia, and the Coast. Several data sources were used to create the model, including leptospirosis records from Ecuador's Ministry of Public Health, national and international literature, and expert elicitation, all of which were incorporated in a Bayesian framework. We were able to determine the most critical parameters influencing each scenario's output (CSU) sensitivity through sensitivity analysis. The Coast region had the best sensitivity scenario, with a median of 0.85% (IC 95% 0.41-0.99), followed by the Amazonia with a median of 0.54% (CI 95% 0.18-0.99) and the Andes with a median of 0.29% (CI 95% 0.02-0.89). As per the sensitivity study, the most influential criteria on the system's sensitivity were "Attendance or probability of going to a health center" and "probability of having symptoms," notably for the Coast and Amazonia Regions.

Bovine Viral Diarrhea Virus within and herd prevalence on pasture-based dairy systems, in southern Chile dairy farms.

Bovine Viral Diarrhea (BVD) is a ubiquitous endemic disease in most bovine populations that causes a negative economic impact on cattle production systems. However, true herd and individual prevalence in Chile have not been estimated based on statistical and epidemiological considerations and uncertainty regarding the infection's extension at animal and herd levels. In addition, the risk factors that can influence how the infection has spread among the cattle premises have not been assessed yet. Therefore, the study aimed to estimate true herd and animal prevalence of active BVDV infection in pasture-based dairy herds and to evaluate risk factors potentially associated with the status of herds and the within-herd prevalence, using a Bayesian approach. A cross-sectional study was performed over a random stratified (proportional to herd size) sample of one-hundred and fifty dairy herds selected in Chile's two leading dairy regions (Region de Los Ríos and Region de Los Lagos). We obtained 12.311 blood samples from lactating cows, but 4.998 randomly selected samples were processed due to budget constraints. For estimating BVDV Herd Prevalence (HP), a herd was considered infected if at least one positive animal to Ag-ELISA was found. In addition, a survey was completed on each farm, aiming to collect information to assess the influence of some variables over the state of the herds; both estimations were obtained using a Bayesian approach. True herd prevalence and true individual prevalence of BVDV active infection were estimated at 77 % and 3.5 % respectively, no significant differences were found between characteristics like herd size, location, vaccination, etc. Open herds and herds that mix herd categories are more likely to have higher BVDV prevalence.