Synergistic Antibacterial Effects of Amoxicillin and Gold Nanoparticles: A Therapeutic Option to Combat Antibiotic Resistance.

Compacted Au@16-mph-16/DNA-AMOX (NSi) nanosystems were prepared from amoxicillin (AMOX) and precursor Au@16-mph-16 gold nanoparticles (Ni) using a Deoxyribonucleic acid (DNA) biopolymer as a glue. The synthesized nanocarrier was tested on different bacterial strains of Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae to evaluate its effectiveness as an antibiotic as well as its internalization. Synthesis of the nanosystems required previous structural and thermodynamic studies using circular dichroism (CD) and UV-visible techniques to guarantee optimal complex formation and maximal DNA compaction, characteristics which facilitate the correct uptake of the nanocarrier. Two nanocomplexes with different compositions and structures, denoted NS1 and NS2, were prepared, the first involving external Au@16-mph-16 binding and the second partial intercalation. The Ni and NSi nanosystems obtained were characterized via transmission electron microscopy (TEM), zeta potential, and dynamic light scattering (DLS) techniques to measure their charge, aggregation state and hydrodynamic size, and to verify their presence inside the bacteria. From these studies, it was concluded that the zeta potential values for gold nanoparticles, NS1, and NS2 nanosystems were 67.8, -36.7, and -45.1 mV. Moreover, the particle size distribution of the Au@16-mph-16 gold nanoparticles and NS2 nanoformulation was found to be 2.6 nm and 69.0 nm, respectively. However, for NS1 nanoformulation, a bimodal size distribution of 44 nm (95.5%) and 205 nm (4.5%) was found. Minimal inhibitory concentration (MIC) values were determined for the bacteria studied using a microdilution plates assay. The effect on Escherichia coli bacteria was notable, with MIC values of 17 µM for both the NS1 and NS2 nanosystems. The Staphylococcus aureus chart shows a greater inhibition effect of NS2 and NP2 in non-diluted wells, and clearly reveals a great effect on Streptococcus pneumoniae, reaching MIC values of 0.53 µM in more diluted wells. These results are in good agreement with TEM internalization studies of bacteria that reveal significant internalization and damage in Streptococcus pneumoniae. In all the treatments carried out, the antibiotic capacity of gold nanosystems as enhancers of amoxicillin was demonstrated, causing both the precursors and the nanosystems to act very quickly, and thus favoring microbial death with a small amount of antibiotic. Therefore, these gold nanosystems may constitute an effective therapy to combat resistance to antibiotics, in addition to avoiding the secondary effects derived from the administration of high doses of antibiotics.

Use of Nanoparticles to Prevent Resistance to Antibiotics-Synthesis and Characterization of Gold Nanosystems Based on Tetracycline.

Antimicrobial resistance (AMR) is a serious public health problem worldwide which, according to the World Health Organization (WHO), requires research into new and more effective drugs. In this work, both gold nanoparticles covered with 16-3-16 cationic gemini surfactant (Au@16-3-16) and DNA/tetracycline (DNA/TC) intercalated complexes were prepared to effectively transport tetracycline (TC). Synthesis of the Au@16-3-16 precursor was carried out by using trihydrated gold, adding sodium borohydride as a reducing agent and the gemini surfactant 16-3-16 as stabilizing agent. Circular dichroism and atomic force microscopy techniques were then used to ascertain the optimal R range of the relationship between the concentrations of Au@16-3-16 and the DNA/TC complex (R = CAu@16-3-16/CDNA) that allow the obtainment of stable and compact nanosystems, these characteristics being fundamental for their use as antibiotic transporters. Stability studies over time were carried out for distinct selected Au@16-3-16 and Au@16-3-16/DNA-TC nanoformulations using the ultraviolet−visible spectrophotometry technique, checking their stability for at least one month. In addition, in order to know the charge and size distribution of the nanocomplexes, DLS and zeta potential measurements were performed in the solution. The results showed that the characterized nanosystems were highly charged, stable and of a reduced size (<100 nm) that allows them to cross bacterial membranes effectively (>1 µm). Once the different physicochemical characteristics of the gold nanosystems were measured, Au@16-3-16 and Au@16-3-16/DNA-TC were tested on Escherichia coli and Staphylococcus aureus to study their antibacterial properties and internalization capacity in microbes. Differences in the interaction of the precursors and the compacted nanosystems generated were observed in Gram-positive and Gram-negative bacteria, possibly due to membrane damage or electrostatic interaction with internalization by endocytosis. In the internalization experiments, depending on the treatment application time, the greatest bacterial destruction was observed for all nanoformulations explored at 18 h of incubation. Importantly, the results obtained demonstrate that both new nanosystems based on TC and Au@16-3-16 precursors have optimal antimicrobial properties and would be beneficial for use in patients, avoiding possible side effects.

Seroprevalence and risk factors associated with bovine leukemia virus (BLV) seropositivity in cattle herds from Ecuador / Seroprevalencia y factores de riesgo asociados a la seropositividad al virus de la leucemia bovina (BLV) en explotaciones de producción bovina en Ecuador / Seroprevalência e fatores de risco associados à soropositividade do vírus da leucemia bovina (BLV) em rebanhos bovinos do Equador

Abstract Background: Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). This disease mainly affects cattle, causing severe economic losses to producers. Objective: To establish individual and herd seroprevalence and determine the risk factors associated with BLV seropositivity for dairy and dual-purpose cattle herds in Ecuador. Methods: A total of 2,668 serum samples from 386 herds were collected. A questionnaire, including variables related to cattle health, management and the environment was completed by each herd. A commercial blocking enzyme-linked immunosorbent assay (ELISA) test was used to determine seropositivity. A generalized estimating equation model (GEE) was developed to determine the factors associated with BLV seropositivity. Results: Individual seroprevalence of BLV infection in Ecuador was 17.3% (CI95% = 15.86-18.74%). Herd prevalence was 37.8% (CI95% = 33.0-42.6%), and intra-herd prevalence ranged between 12.5 and 100% (median: 37.5%). The risk factors associated with BLV seropositivity were artificial insemination (OR: 2,215; CI95% =1.402-3.501), concrete floors (OR: 2.178; CI95% = 1.217-3.889), presence of wild ruminants (OR: 2.998; CI95% = 1.788-5.027), and sampling season (wet; OR: 1.996; CI95% = 1.140-3.497). Conclusions: Results indicate that BLV is widespread in cattle herds in Ecuador. In addition, the study suggests that a control program to fight BLV infection should focus on controlling the risk factors identified.

Resumen Antecedentes: El virus de la leucosis bovina (BLV) es el principal agente etiológico causante de la leucosis enzoótica bovina (EBL). Esta enfermedad afecta a los bovinos causando grandes pérdidas económicas a los productores. Objetivo: Establecer la seroprevalencia y dispersión del BLV, así como los factores de riesgo asociados a la seropositividad en explotaciones lecheras y de doble propósito en Ecuador. Métodos: Se recolectó un total de 2.668 muestras de suero de 386 explotaciones. Se aplicó un cuestionario que incluyó variables relacionadas con la salud del hato, medidas de manejo, y características ambientales de cada explotación. Para los análisis serológicos se utilizó un test inmunológico ligado a enzimas (ELISA). Para definir los factores de riesgo asociados a la seropositividad a BLV se desarrolló un modelo utilizando ecuaciones de estimación generalizadas (GEE). Resultados: La seroprevalencia de BLV en Ecuador fue de 17,3% (IC95% = 15,86-18,74%). La dispersión fue de 37,8% (IC95%= 33,0-42,6%), y la prevalencia intra-hato alcanzó rangos entre 12,5-100% (media: 37,5%). Los factores de riesgo asociados a la seropositividad a BLV fueron: inseminación artificial (OR: 2,215; IC95% = 1,402-3,501), piso de concreto (OR: 2,178; IC95% = 1,217-3,889), presencia de rumiantes salvajes (OR: 2,998; IC95% = 1,788-5,027), y temporada de muestreo (húmeda; OR: 1,996; IC95% = 1,140-3,497). Conclusiones: Los resultados indican que el BLV se encuentra disperso en las explotaciones de Ecuador. Adicionalmente, se sugiere la implementación de un programa de control para la lucha contra el BLV, debiéndose considerar medidas que se enfoquen al control de los factores de riesgo identificados en esta investigación.

Resumo Antecedentes: O vírus da leucemia bovina (BLV) é o principal agente causador da leucose enzoótica bovina (EBL). Esta doença afeta o gado causando graves prejuízos econômicos aos produtores. Objetivo: Estabelecer a soroprevalência e dispersão do BLV, assim como os fatores de risco associados à soropositividade nas produções leiteiras e de duplo propósito no Equador. Métodos: Um total de 2.668 amostras de soro de 386 explorações foram coletadas. Foi aplicado um questionário que incluía variáveis relacionadas à saúde do rebanho, medidas de manejo e ambiente para cada exploração. Para a análise sorológica foi utilizado um teste imunológico sobre enzimas (ELISA) para determinação da soropositividade. Para definir os fatores de risco associados à soropositividade a BLV, foi utilizado um modelo de equações estimativas generalizadas (GEE). Resultados: A soroprevalência de BLVno Equador é de 17,3% (IC95% = 15,86-18,74%). La dispersão de 37,8% (IC95% = 33,0-42,6%), e a prevalência intra-rebanho alcançou entre 12,5-100% (media: 37,5%). Os fatores de risco associados à soropositividade a BLV foram inseminação artificial (OR: 2,215; IC95% = 1,402-3,501), chão de concreto (OR: 2,178; IC95% = 1,217-3,889), presença de ruminantes selvagens (OR: 2,998; IC95% = 1,788-5,027) e época da amostragem (úmida; OR: 1,996; IC95% = 1,140-3,497). Conclusões: Os resultados indicam que o BLV se encontra disseminado nas explorações no Equador. Adicionalmente, o estudo pode contribuir para a implementação de um programa de controle para a luta contra o BLV, devendo-se considerar ações de controle dos fatores de risco identificados nesta investigação.

Bovine Coronavirus Immune Milk Against COVID-19.

After a year of evolution of the SARS-CoV-2 epidemic, there is still no specific effective treatment for the disease. Although the majority of infected people experience mild disease, some patients develop a serious disease, especially when other pathologies concur. For this reason, it would be very convenient to find pharmacological and immunological mechanisms that help control SARS-CoV-2 infection. Since the COVID-19 and BCoV viruses are very close phylogenetically, different studies demonstrate the existence of cross-immunity as they retain shared epitopes in their structure. As a possible control measure against COVID-19, we propose the use of cow's milk immune to BCoV. Thus, the antigenic recognition of some highly conserved structures of viral proteins, particularly M and S2, by anti-BCoV antibodies present in milk would cause a total or partial inactivation of SARS-COV-2 (acting as a particular vaccine) and be addressed more easily by GALT's highly specialized antigen-presenting cells, thus helping the specific immune response.

Antimicrobial resistance of Pasteurella multocida type B isolates associated with acute septicemia in pigs and cattle in Spain.

BACKGROUND: Pasteurella multocida is the etiological agent responsible for several diseases in a wide range of hosts around the world and thus, causes serious economic losses. Acute septicemia associated with capsular type B P. multocida has recently emerged in Europe and continuous outbreaks of these acute processes have been described in Spain since they were first detected in pigs in 2009 and cattle in 2015. The scarcity of studies on the antimicrobial susceptibility of this capsular type of P. multocida and growing concern about the general increase of antimicrobial resistance mean that studies related to the performance of type B P. multocida against antibiotics are necessary to establish accurate treatments and to monitor antimicrobial resistances. RESULTS: Seventy-six isolates of P. multocida type B from pigs and cattle with acute septicemia were tested for susceptibility to 10 different antimicrobials. Bovine isolates were susceptible to all the antibiotics we tested except for lincomycin (94.4% of isolates were resistant). However, the antimicrobials we tested were less effective against swine isolates, of which none were susceptible to lincomycin. Furthermore, 29.3% swine isolates were resistant to tetracycline, 27.6% to penicillin, 20.7% to oxytetracycline, 17.3% to chloramphenicol, 15.5% to gentamicin, and 3.4% to enrofloxacin; no resistance to ceftiofur was detected. No multidrug resistant isolates were detected from cattle, while 25.86% of swine isolates were resistant to three or more antibiotic classes. CONCLUSIONS: In this study, the lower resistance rates and multidrug resistant isolates reported for P. multocida type B derived from cattle compared to those isolated from pigs may be related to the increased use of antibiotics in the porcine industry in Spain. Lincomycin is not recommended for the treatment of acute septicemia in pigs or cattle, rather, the use of ceftiofur, enrofloxacin, or gentamicin is indicated as an emergency treatment in the early stages of disease; once the susceptibility results are known, the use of tetracyclines, penicillin, or chloramphenicol should be prioritized. The increase in multidrug resistant isolates and antimicrobial resistance rates indicates that more attention should be paid to prevention as well as the responsible use of antibiotics.

First outbreak of bovine haemorrhagic septicaemia caused by Pasteurella multocida type B in Spain - Short communication.

This paper describes the first documented outbreak of haemorrhagic septicaemia (HS) caused by Pasteurella multocida type B in cattle in Spain. This acute, highly fatal septicaemia causes major economic losses in cattle and buffaloes in many areas of Asia and Africa. In other species and in European countries it is an infrequently reported disease. Acute septicaemic pasteurellosis occurred in a free-range farm of 150 cattle and 70 beef calves in Southern Spain. Twenty-one calves and one cow were affected, of which three calves and the adult cow died. Postmortem examination revealed characteristic oedema in the ventral area of the neck and the brisket region, and widespread haemorrhages in all organs. Pure cultures of P. multocida were obtained from all tissues and organs studied. The aetiological agent was further confirmed by molecular and biochemical analysis as P. multocida capsular type B, biovar 3. Although the source of infection could not be determined, wildlife may play an important role. The use of tulathromycin in the initial stage of the disease might be related to the low morbidity and mortality of this outbreak. After using an autogenous vaccine no more cases of HS were observed.

Epizootic Situation of Feline Bartonella Infection in Eastern Poland.

INTRODUCTION: The aim of the study was to establish the prevalence of Bartonella spp. in cats in eastern Poland, and to determine the factors associated with the infection. MATERIAL AND METHODS: PCRs were performed to detect Bartonella DNA in the whole blood of 672 cats from four regions in eastern Poland (the Lublin, Podlasie, Masovian, and Subcarpathian provinces). The association between the previously selected variables and the dependent variable (presence of Bartonella DNA) was investigated using a logistic regression model. RESULTS: The overall prevalence of infection was 40.48%. All PCR positive cats were infected with B. henselae. The living conditions of the animals (free outdoor roaming), mixed breed cats, Subcarpathian region, and absence of tick control were significant risk factors associated with Bartonella infection at a 95% confidence level. CONCLUSION: Cats in eastern Poland appear to be at risk of a bartonellosis epizootic. Factors which seem to impact the likelihood of infection in cats and factors which seem not to impact it have been suggested. We advocate additional research into the ways bartonellosis spreads, its geographical scope, and the factors that favour its development.

Detection of canine vector-borne diseases in eastern Poland by ELISA and PCR.

The aim of the study was to establish the prevalence of Ehrlichia canis, Anaplasma phagocytophilum and Borrelia burgdorferi in dogs in eastern Poland and to determine the factors associated with exposure (seroposity) or infection (PCR). Anti-A. phagocytophilum, anti-B. burgdorferi and anti-E. canis antibodies were determined in 400 dogs, using the SNAP 4Dx ® test (IDEXX Laboratories). In addition, PCRs were performed for the detection of E. canis, A. phagocytophilum and B. burgdorferi DNA. In reference to the risk factor analysis, a regression logistic model was determined for each aetiological agent. The overall seroprevalence was highest for B. burgdorferi (11.0 %), followed by A. phagocytophilum (8.0 %) and E. canis (1.5 %). Eleven healthy dogs were found to be infected with A. phagocytophilum, as determined by PCR, while the remainder were seronegative. For B. burgdorferi, the DNA of the spirochetes was detected in the blood of 20 dogs, while the presence of anti-B. burgdorferi IgG was detected in the sera of ten of these. For E. canis, none of the dogs tested positive by PCR. Tick control was included as a protective factor for A. phagocytophilum and B. burgdorferi, while the origin (rural) was included as a risk factor for B. burgdorferi and A. phagocytophilum infection. In addition, breed (pure) was a risk factor for B. burgdorferi infection, and sex (female) was a risk factor for E. canis.

Higher resistance of Campylobacter coli compared to Campylobacter jejuni at chicken slaughterhouse.

In order to compare the prevalence of Campylobacter coli and Campylobacter jejuni during the processing of broilers at slaughterhouse a total of 848 samples were analyzed during 2012 in southern Spain. Four hundred and seventy six samples were collected from cloaca, carcass surfaces and quartered carcasses. Moreover, 372 environmental swabs from equipment and scalding water were collected. Minimum inhibitory concentration (MIC) to ciprofloxacin, erythromycin, streptomycin, tetracycline and gentamicin was determined for isolates from chicken meat. The general prevalence of Campylobacter was 68.8% (40.2% of C. coli and 28.5% of C. jejuni). The relative prevalence of C. coli increased from loading dock area (41.5%) to packing area (64.6%). In contrast, the relative prevalence of C. jejuni decreased from 58.5% to 35.4%. These differences between species from initial to final area were significant (p=0.02). The highest antimicrobial resistance for C. jejuni and C. coli was detected to tetracycline (100%) and ciprofloxacin (100%), respectively. Campylobacter coli showed an antimicrobial resistance significantly higher than C. jejuni to streptomycin (p=0.002) and erythromycin (p<0.0001).

Coxiella burnetii seroprevalence and associated risk factors in dairy and mixed cattle farms from Ecuador.

Q fever is a zoonotic disease caused by Coxiella burnetii, a bacterial agent for which ruminants are the main reservoir. An extensive cross-sectional study to determine the seroprevalence of and associated risk factors for Q fever was performed in dairy and mixed (dairy-beef) cattle herds in Ecuador. A total of 2668 serum samples from 386 herds were analyzed using an ELISA. In addition, a questionnaire with 57 variables related to management, feeding, facilities, biosecurity and animal health was completed for every cattle farm. A Generalized Estimating Equations model was used to determine the factors associated with C. burnetii seropositivity. The true prevalence of C. burnetii seropositivity in dairy and mixed cattle from Ecuador reached 12.6% (CI95%: 11.3-13.9%). The herd prevalence was 46.9% (181/386) (CI95%: 41.9-51.9%), and the within herd prevalence ranged between 8% and 100% (mean: 25.0%; Q1: 12.5%, Q2: 25.0%, Q3: 37.5%). Four factors were included in the GEE model for C. burnetii seropositivity: age of the cattle (OR: 1.01; CI95%: 1.006-1.014), feeding of calves with milk replacers (OR: 1.94; CI95%: 1.1-3.3), bovine respiratory syncytial virus seropositivity (OR: 1.54; CI95%: 1.1-2.3), and disinfection of the umbilical cord (OR: 0.60; CI95%: 0.4-0.9).

Prevalence and risk factors of Campylobacter infection in broiler flocks from southern Spain.

An extensive epidemiological study was performed to determine the prevalence and risk factors of Campylobacter infection in broiler farms in Andalusia (southern Spain). A total of 2221 cloacal swabs and 747 environmental swabs from 291 broiler flocks were screened between April 2010 and May 2012. The prevalence of Campylobacter in individual animals was 38.1%, and the flock prevalence was 62.9%. Flocks were predominantly infected by C. jejuni and C. coli but were also infected by untyped Campylobacter spp., and mixed-species infection could be found. Risk factors for Campylobacter infection were assessed from direct interview of the farmers. The number of positive samples by flock was modelled assuming a binomial distribution. Analysis indicated five factors associated with increased intra-flock prevalence: presence of dogs or cats on the farm, older age of the broiler flock, the application of thinning of flocks, the presence of windows with canvas blinds, and the presence of rodents in the poultry house. Two factors were associated with decreased intra-flock prevalence: the treatment of drinking water and having an entrance room for access into the poultry house. This is the first study performed on broilers farms from Spain reporting the risk factors of Campylobacter infection and is the largest study on the prevalence of Campylobacter infection.

Comparative analysis of 16S RNA nucleotide sequences of Anaplasma phagocytophilum detected in the blood of horses from various parts of Europe.

The aim of this study was to conduct a comparative analysis of the 16S rRNA gene fragment nucleotide sequences for Anaplasma phagocytophilum strains detected in the blood of horses from various parts of Europe. The study comprised 234 horses that had had contact with ticks. Using PCR, the genetic material of A. phagocytophilum was identified in the blood of 42 animals. The sequences of the 16S RNA gene amplicons that were obtained from our A. phagocytophilum isolates had 100 % similarity with each other and 96.4-100 % similarity with Anaplasma spp. sequences selected from those available in GenBank. Nucleotide substitutions at positions 248 and 249 were demonstrated in all the 16S RNA gene sequences of Anaplasma obtained in our study. This may indicate the emergence of a new rickettsial genotype that is the cause of equine granulocytic anaplasmosis in southern and eastern Europe. These results add new information on the epidemiology and genetic diversity of A. phagocytophilum detected in the blood of horses from southern and eastern Europe.

Seroprevalence and risk factors associated with Babesia caballi and Theileria equi infection in equids.

A cross-sectional study was carried out on equids (horses, mules and donkeys) in Andalusia, Southern Spain, to assess the level of exposure to equine piroplasmosis and to investigate risk factors associated with these infections. At least one animal seropositive for Theileria equi and/or Babesia caballi was detected in 222/380 (58.4%) herds sampled by competitive inhibition ELISAs. The seroprevalences for B. caballi and T. equi were 13.2% and 56.1%, respectively; there was serological evidence of co-circulation of both piroplasms in 10.8% of herds. Antibodies against equine piroplasms were detected in 286/537 (53.3%) animals; 61 (11.4%) were seropositive for B. caballi, 270 (50.3%) were seropositive for T. equi and 24 (8.4%) were seropositive for both T. equi and B. caballi. There was a significantly higher seroprevalence of B. caballi in mules (32.1%) compared with donkeys (17.0%) and horses (7.9%), and a significantly higher seroprevalence of T. equi in mules (66.1%) in comparison with horses (48.6%), but not donkeys (47.2%). There were significant differences in prevalence of both piroplasms among locations; the seroprevalence of B. caballi ranged from 0 to 22.5%, while the seropositivity to T. equi ranged from 26.7 to 63.3%. A multiple logistic regression model indicated that the risk factors associated with a higher T. equi seroprevalence were increased age, presence of ticks and vaccination against other diseases. Risk factors associated with a higher seroprevalence of B. caballi were species (mules compared to horses), entry of horses in the last 6months, presence of ticks and presence of shelter. The findings indicate widespread exposure to equine piroplasmosis in Southern Spain.

Identification of piroplasms isolated from asymptomatic equine species from southern Spain.

The aim of the study was to detect the presence of genetic material of equine piroplasmas and to determine the species isolates from apparently healthy equids, including horses, donkeys and mules, in southern Spain. Blood samples were collected from 135 animals to assess the presence of DNA from equine piroplasmas using PCR. Babesia (B.) caballi DNA was detected in blood samples of three horses and one donkey, while Theileria (T.) equi DNA was confirmed in blood of 19 horses, three mules and one donkey. All B. caballi isolates showed a 100% homology of the nucleotide sequence of the 18S RNA gene fragment with the Spanish isolate AY534883. T. equi isolates had a 99.8% homology with the Spanish isolate T. equi AY 534882 and a 98.2% homology with the sequence of the Spanish isolate T. equi DQ287951. The differences in the nucleotide sequence of 18S RNA gene between T. equi isolates in the present study and the above mentioned Spanish isolates suggest the circulation of different genotypes in this country. The presence of genetic material of these parasites in 20% of the examined animals indicates a widespread exposure to equine piroplasmosis in southern Spain, therefore, a monitoring program in this country is needed.

Prevalence of and risk factors for bovine respiratory syncytial virus (BRSV) infection in non-vaccinated dairy and dual-purpose cattle herds in Ecuador.

A cross-sectional study was carried out to determine the seroprevalence and risk factors associated with bovine respiratory syncytial virus (BRSV) infection in non-vaccinated dairy and dual-purpose cattle herds from Ecuador. A total of 2,367 serum samples from 346 herds were collected from June 2008 to February 2009. A questionnaire, which included variables related to cattle, health, management measures, and the environment, was filled out in each herd. Presence of antibodies against BRSV was analyzed using a commercial indirect ELISA test. A logistic regression model was used to determine risk factors associated with BRSV at herd level. The individual seroprevalence against BRSV in non-vaccinated herds in Ecuador was 80.48% [1,905/2,367; 95% confidence interval (CI) = 78.9-82.1]. The herd prevalence was 91.3% (316/346; 95% CI = 88.3-94.3), and the intra-herd prevalence ranged between 25% and 100% (mean, 90.47%). The logistic regression model showed that the existence of bordering cattle farms, the dual-purpose farms, and the altitude of the farm (more than 2,338 m above sea level) were risk factors associated with BRSV infection. This is the first study about BRSV prevalence in Ecuador. It shows the wide spread of the BRSV infection in the country. The risk factors found will help to design effective control strategies.

Seroprevalence and risk factors associated with bovine viral diarrhea virus (BVDV) infection in non-vaccinated dairy and dual purpose cattle herds in Ecuador.

A cross-sectional study was carried out to determine the seroprevalence and risk factors associated with Bovine viral diarrhea virus (BVDV) infection in non-vaccinated dairy and dual-purpose cattle herds from Ecuador. A total of 2,367 serum samples from 346 herds were collected from June 2008 through February 2009. A questionnaire, which included variables related to cattle, health, management measures, and the environment, was filled out in each herd. A commercial indirect enzyme-linked immunosorbent assay test was used to determine the seropositivity. A logistic regression model was used to determine risk factors at herd level. The individual seroprevalence for BVDV in non-vaccinated herds in Ecuador was 36.2% (857/2,367; CI(95%), 34.3-38.1%). The herd prevalence was 74% (256/346; CI(95%), 69.4-78.6%) and the intra-herd prevalence ranged between 11.1% and 100% (mean = 51.6%). The logistic regression model showed that the density of cattle farms in the area (more than 70%; OR, 1.94; CI(95%), 1.21-3.2) and the altitude (higher than 2,338 m above sea level; 2.33; CI(95%), 1.4-3.9) are potential risk factors associated with BVDV infection.

Factors affecting the seroprevalence of lagovirus infection in wild rabbits (Oryctolagus cuniculus) in Southern Spain.

Cross-sectional studies were carried out on wild rabbit (Oryctolagus cuniculus) populations in Southern Spain to assess the prevalence of lagovirus infection and to identify potentially associated risk factors. A total of 619 blood and 487 liver samples from wild rabbits were collected from seven hunting areas with different Mediterranean ecosystems. Logistic regression analysis was used to assess associations between seropositivity and an extensive set of variables. The seroprevalence was 29.2% (95% CI: 25.6-32.8) and lagoviruses were not detected in liver samples. Logistic regression indicated that seropositivity to lagoviruses was associated with seropositivity to myxomatosis, wild rabbit density, the existence of artificial feeding sites, mean maximum monthly temperatures of 20-30 °C, and annual accumulated rainfall of >600 mm.