Spatial clusters, temporal behavior, and risk factors analysis of rabies in livestock in Ecuador.

Rabies, a globally distributed and highly lethal zoonotic neglected tropical disease, has a significant impact in South America. In Ecuador, animal rabies cases are primarily linked to livestock, and hematophagous bats play a crucial role in disease transmission. This study aims to identify temporal trends, spatial patterns, and risk factors for animal rabies in Ecuador between 2014 and 2019. Epidemiological survey reports from the official Animal Rabies Surveillance Program of the Phyto and Zoosanitary Regulation and Control Agency of Ecuador (AGROCALIDAD) were used. The Animal Rabies Surveillance Program from AGROCALIDAD consists of an official passive surveillance program that receives reports from farmers or individuals (both trained or untrained) who have observed animals with neurological clinical signs and lesions compatible with bat bites, or who have seen or captured bats on their farms or houses. Once this report is made, AGROCALIDAD personnel is sent for field inspection, having to confirm the suspicion of rabies based on farm conditions and compatibility of signs. AGROCALIDAD personnel collect samples from all suspicious animals, which are further processed and analyzed using the Direct Fluorescent Antibody (DFA) test for rabies confirmatory diagnosis. In this case, study data comprised 846 bovine farms (with intra-farm sample sizes ranging from 1 to 16 samples) located in different ecoregions of Ecuador; out of these, 397 (46.93%) farms tested positive for animal rabies, revealing six statistically significant spatial clusters. Among these clusters, three high-risk areas were identified in the southeast of Ecuador. Seasonality was confirmed by the Ljung-Box test for both the number of cases (p < 0.001) and the positivity rate (p < 0.001). The Pacific Coastal lowlands and Sierra regions showed a lower risk of positivity compared to Amazonia (OR = 0.529; 95% CI = 0.318 - 0.883; p = 0.015 and OR = 0.633; 95% CI = 0.410 - 0.977; p = 0.039, respectively). The breeding of non-bovine animal species demonstrated a lower risk of positivity to animal rabies when compared to bovine (OR = 0.145; 95% CI = 0.062 - 0.339; p < 0.001). Similarly, older animals exhibited a lower risk (OR = 0.974; 95% CI = 0.967 - 0.981; p < 0.001). Rainfall during the rainy season was also found to decrease the risk of positivity to animal rabies (OR = 0.996; 95% CI = 0.995 - 0.998; p < 0.001). This study underscores the significance of strengthening the national surveillance program for the prevention and control of animal rabies in Ecuador and other countries facing similar epidemiological, social, and geographical circumstances.

High Exposure to Livestock Pathogens in Southern Pudu (Pudu puda) from Chile.

A significant gap in exposure data for most livestock and zoonotic pathogens is common for several Latin America deer species. This study examined the seroprevalence against 13 pathogens in 164 wild and captive southern pudu from Chile between 2011 and 2023. Livestock and zoonotic pathogen antibodies were detected in 22 of 109 wild pudus (20.18%; 95% CI: 13.34-29.18) and 17 of 55 captive pudus (30.91%; 95% CI: 19.52-44.96), including five Leptospira interrogans serovars (15.38% and 10.71%), Toxoplasma gondii (8.57% and 37.50%), Chlamydia abortus (3.03% and 12.82%), Neospora caninum (0.00% and 9.52%), and Pestivirus (8.00% and 6.67%). Risk factors were detected for Leptospira spp., showing that fawn pudu have statistically significantly higher risk of positivity than adults. In the case of T. gondii, pudu living in "free-range" have a lower risk of being positive for this parasite. In under-human-care pudu, a Pestivirus outbreak is the most strongly suspected as the cause of abortions in a zoo in the past. This study presents the first evidence of Chlamydia abortus in wildlife in South America and exposure to T. gondii, L. interrogans, and N. caninum in wild ungulate species in Chile. High seroprevalence of livestock pathogens such as Pestivirus and Leptospira Hardjo in wild animals suggests a livestock transmission in Chilean template forest.

Specific and non-specific effects of Mycobacterium bovis BCG vaccination in dairy calves.

Bovine tuberculosis (bTB) is a chronic disease mainly caused by Mycobacterium bovis, a zoonotic pathogen with economic significance as it leads to reduced milk and meat production, and high costs for control measures. The Bacillus Calmette-Guérin (BCG) vaccine, primarily used to prevent tuberculosis in humans, has also been studied for controlling bTB. While showing effectiveness in preventing M. bovis infection and disease in cattle, the BCG vaccine can induce non-specific effects on the immune system, enhancing responses to infections caused by unrelated pathogens, and also having non-specific effects on lactation. The aim of this study is to describe both the specific and non-specific effects of BCG vaccination in calves from a commercial dairy herd in central Chile. Diagnosis of M. bovis infection was performed through the IFNγ release assay (IGRA) using ESAT6/CFP-10 and Rv3615c antigens. The records of milk production, somatic cell count (SCC), clinical mastitis (CM) and retained placenta (RP) during the first lactation were compared between vaccinated and non-vaccinated animals. The breed (Holstein Friesian [HF] v/s HF × Swedish Red crossbred [HFSR]) and the season (warm v/s cold) were also analyzed as categorical explanatory variables. Results of IGRA showed significant differences between vaccinated and control groups, indicating a vaccine efficacy of 58.5% at 18 months post vaccination in HFSR crossbred animals. Although milk production did not vary, SCC and CM showed differences between groups, associated to the breed and the season, respectively. When analyzing CM and RP as a whole entity of disease, BCG showed protection in all but the cold season variables. Overall, the BCG vaccine induced protective specific and non-specific effects on health parameters, which may be influenced by the breed of animals and the season. These results provide new features of BCG protection, supporting initiatives for its implementation as a complementary tool in bTB control.

Antimicrobial susceptibility of Rhodococcus equi strains isolated from foals in Chile.

Rhodococcus equi is responsible for foal pneumonia worldwide, with a significant economic impact on the production and breeding of horses. In Chile, the first case was reported in 2000, and since then, its incidence has been increasing. Distinctive characteristics of R. equi as an intracellular pathogen in macrophages, emergence of virulence plasmids encoding surface lipoprotein antigens, and appearance of antibiotic resistance against macrolides and rifampicin have significantly complicated the treatment of R. equi pneumonia in foals. Therefore, in vitro susceptibility studies of first-line and newer antibiotics against R. equi are the first step to establishing effective treatments and optimizing new therapeutic options. The aim of the present study is to determine the susceptibility profile of fourteen strains of R. equi isolated from foals in Chile to several antibiotics of the macrolide group including azithromycin, amikacin, tildipirosin and gamithromycin as well as others such as rifampicin, doxycycline and ceftiofur. Identification of R. equi in collected isolates from foals in Chile has been performed by CAMP test and PCR based on detecting of the gene encoding the 16 S rRNA. The presence of genes encoding virulence plasmids was also determined using PCR. Results obtained have demonstrated presence of virulent R. equi strains in Chile. In vitro susceptibility pattern to different antibiotics has shown better results for doxycycline and rifampicin similar to previous studies performed. Current macrolides have been evaluated in order to consider alternative treatment options in a context of emerging resistance to classic macrolides and rifampicin, obtaining better results with gamithromycin (MIC range of 0.125 to 128 mg/ml) than with tildipirosin (MIC range of 16 to 128 mg/ml). An adequate diagnosis of bacterial susceptibility based on antibiograms is necessary to treat the Rhodococcus equi infection in foals.

Vaccination of Calves with the Mycobacterium bovis BCG Strain Induces Protection against Bovine Tuberculosis in Dairy Herds under a Natural Transmission Setting.

Bovine tuberculosis (bTB) is a zoonotic disease caused mainly by Mycobacterium bovis, which is associated with major economic losses for milk and meat producers. The objective of this trial was to assess the efficacy of the BCG Russia strain in a cohort study performed under field conditions, with the vaccination of calves in seven dairy farms from a high prevalence area in central Chile. The trial was performed with 501 animals, subcutaneously vaccinated with 2-8 × 105 colony-forming units of BCG, whilst 441 matched control animals received a saline placebo. Peripheral blood was collected at 6, 12 and 18 months post-vaccination, and infection status was determined using the IFNγ release assay in conjunction with the DIVA (Detecting Infected amongst Vaccinated Animals) antigens ESAT-6, CFP-10 and Rv3615c. The BCG vaccine showed a low but significant level of protection of 22.4% (95% CI 4.0 to 36.4) at the end of the trial. However, diverse levels of protection and a variable duration of immunity were observed between trial herds. This diverse outcome could be influenced by the general health condition of calves and their exposition to non-tuberculous mycobacteria. These results suggest that BCG vaccination of dairy calves in a natural transmission setting confers variable protection to animals against bTB in a high prevalence area.

Vaccination of Holstein heifers with Mycobacterium bovis BCG strain induces protection against bovine tuberculosis and higher milk production yields in a natural transmission setting.

Bovine tuberculosis (TB) is a chronic disease caused mainly by Mycobacterium bovis, a zoonotic pathogen that has a worldwide distribution causing serious economic losses for milk and meat producers. In Chile, the disease in dairy cattle has a heterogeneous distribution, where the Metropolitan Region concentrates the highest animal prevalence and the main challenge for the national control and eradication programme. In this epidemiological context, vaccination with the M. bovis Bacillus Calmette-Guerin (BCG) vaccine might be a useful strategy for disease prevention and control. The objective of this study was to assess the efficacy and impacts on productivity and fertility of vaccination with the BCG Russia strain in 11 month-old heifers from a dairy farm, under a natural transmission condition. Sixty-two animals were vaccinated via the subcutaneous route with the equivalent of one human dose of BCG, and 60 control animals received saline. Subsequently, blood sampling was performed at 3, 6, 9, 12, 15 and 18 months post-inoculation, and infection status was determined using the IFNγ release assay (IGRA) with the DIVA (differentiate infected from vaccinated animals) antigens ESAT-6, CFP-10 and Rv3615c. Efficacy was calculated as the percentage of reduction in the incidence of infection attributable to vaccination, which showed a statistically significant level of overall protection of 66.5%. No adverse effects on fertility and production were recorded. In contrast, we observed beneficial effects of vaccination on several milk production parameters, with the milk yield in the first 100 days after calving in the BCG group significantly higher compared to unvaccinated heifers (p < .05). These results suggest that BCG vaccination of heifers in a natural transmission setting might result in both sanitary and productive benefits, supporting its implementation as a new strategy for TB prevention in a high prevalence area of Chile.

SEROSURVEY FOR SELECTED PARASITIC AND BACTERIAL PATHOGENS IN DARWIN'S FOX (LYCALOPEX FULVIPES): NOT ONLY DOG DISEASES ARE A THREAT.

The Darwin's fox (Lycalopex fulvipes) is one of the most endangered carnivores worldwide, with the risk of disease spillover from domestic dogs being a major conservation threat. However, lack of epidemiologic information about generalist, non-dog-transmission-dependent protozoal and bacterial pathogens may be a barrier for disease prevention and management. To determine the exposure of some of these agents in Darwin's fox populations, 54 serum samples were collected from 47 Darwin's foxes in Southern Chile during 2013-18 and assessed for the presence of antibodies against Brucella abortus, Brucella canis, Coxiella burnetii, pathogenic Leptospira (serovars Grippotyphosa, Pomona, Canicola, Hardjo, and Copehageni), Toxoplasma gondii, and Neospora caninum. The highest seroprevalence was detected for T. gondii (78%), followed by pathogenic Leptospira (14%). All the studied Leptospira serovars were confirmed in at least one animal. Two foxes seroconverted to Leptospira and one to T. gondii during the study period. No seroconversions were observed for the other pathogens. No risk factors, either intrinsic (sex, age) or extrinsic (season, year, and degree of landscape anthropization), were associated with the probability of being exposed to T. gondii. Our results indicate that T. gondii exposure is widespread in the Darwin's fox population, including in areas with minimal anthropization, and that T. gondii and pathogenic Leptospira might be neglected threats to the species. Further studies identifying the causes of morbidity and mortality in Darwin's fox are needed to determine if these or other pathogens are having individual or population-wide effects in this species.

Survey of Zoonotic Bacterial Pathogens in Native Foxes in Central Chile: First Record of Brucella canis Exposure.

Brucella abortus, B. canis, and pathogenic Leptospira are zoonotic pathogens that infect humans, as well as domestic and wild animals. In wild canids, they may affect their fertility and reproduction, threatening their conservation. Wild canids play a crucial role in the environment as meso- and top-predators and environmental sentinels for zoonotic pathogens. In Chile, three species of wild canids are present, and due to changes in land use and environmental dynamics, it is of utmost relevance to determine the role of these species in the epidemiology of brucellosis and leptospirosis. This study aimed to detect the exposure to B. abortus, B. canis, and pathogenic Leptospira by serologic, bacteriologic, and molecular techniques in native foxes from rehabilitation and exhibition centers in Central Chile. Forty-six blood samples were obtained from Lycalopex culpaeus and L. griseus, detecting 10.9% of seropositivity to B. canis and 7.7% to L. Javanica. No seropositivity was seen for B. abortus. Exposure was not registered by culture and qPCR in any of the sampled animals. Our findings are the first register of exposure to any Brucella species in wild canids in Chile and highlight the need to establish surveillance programs of these emerging pathogens.

Health policy and systems research publications in Latin America warrant the launching of a new specialised regional journal.

BACKGROUND: Scientific journals play a critical role in research validation and dissemination and are increasingly vocal about the identification of research priorities and the targeting of research results to key audiences. No new journals specialising in health policy and systems research (HPSR) and focusing in the developing world or in a specific developing world region have been established since the early 1980s. This paper compares the growth of publications on HPSR across Latin America and the world and explores the potential, feasibility and challenges of innovative publication strategies. METHODS: A bibliometric analysis was undertaken using HPSR MeSH terms with journals indexed in Medline. A survey was undertaken among 2500 authors publishing on HPSR in Latin America (LA) through an online survey, with a 13.1% response rate. Aggregate indicators were constructed and validated, and two-way ANOVA tests were performed on key variables. RESULTS: HPSR publications on LA observed an average annual growth of 27.5% from the years 2000 to 2018, as against 11.4% worldwide and yet a lag on papers published per capita. A total of 48 journals with an Impact Factor publish HPSR on LA, of which 5 non-specialised journals are published in the region and are ranked in the bottom quintile of Impact Factor. While the majority of HPSR papers worldwide is published in specialised HPSR journals, in LA this is the minority. Very few researchers from LA sit in the Editorial Board of international journals. Researchers highly support strengthening quality HPSR publications through publishing in open access, on-line journals with a focus on the LA region and with peer reviewers specialized on the region. Researchers would support a new open access journal specializing in the LA region and in HPSR, publishing in English. Open access up-front costs and disincentives while waiting for an Impact Factor can be overcome. CONCLUSION: Researchers publishing on HPSR in LA widely support the launching of a new specialised journal for the region with a vigorous editorial policy focusing on regional and country priorities. Strategies should be in place to support English-language publishing and to develop a community of practice around the publication process. In the first years, special issues should be promoted through a priority-setting process to attract prominent authors, develop the audience and attain an Impact Factor.

Serologic Survey of Brucella canis and Leptospira spp. in Free-Ranging Wild and Domestic Canids from Tierra del Fuego, Chile.

We investigated exposure to Brucella canis and Leptospira spp. in sera from 56 canids sampled between 2008 and 2012 in Tierra del Fuego, Chile. No seropositives to B. canis were found. We detected antibodies against Leptospira spp. in Fuegian culpeo fox (Pseudalopex culpaeus lycoides; 20%), chilla foxes (Pseudalopex griseus; 8%), and dogs (Canis lupus familiaris; 3%).

Corynebacterium pseudotuberculosis Infection in Patagonian Huemul ( Hippocamelus bisulcus ).

Corynebacterium pseudotuberculosis is an intracellular bacteria and the etiologic agent of caseous lymphadenitis in domestic and wildlife species. We report C. pseudotuberculosis infection in Patagonian huemul ( Hippocamelus bisulcus ) from the Cerro Castillo National Reserve, Region of Aysen, Chile. Subcutaneous abscesses in the abdominal and pectoral regions from two animals were sampled and bacteriologic isolation was performed. In both cases, we isolated a C. pseudotuberculosis strain belonging to the ovine genotype. In addition, one isolate was resistant to ciprofloxacin and streptomycin. We report that H. bisulcus is a susceptible species to this bacterium, which is transmitted by direct or indirect contact with domestic sheep ( Ovis aries ) and which represents a potential conservation threat to populations of H. bisulcus . Additional research and prevention efforts should be addressed.

SEROPREVALENCE OF NINE LEPTOSPIRA INTERROGANS SEROVARS IN WILD CARNIVORES, UNGULATES, AND PRIMATES FROM A ZOO POPULATION IN A METROPOLITAN REGION OF CHILE.

Serum samples from 130 individuals representing 42 species of carnivores, ungulates, and primates from a population of captive mammals in Metropolitan Region in Chile were tested for antibodies against nine serovars of Leptospira interrogans using the microscopic agglutination test. Ten percent of the animals were seropositive to one or more serovars. Seroprevalence was significantly higher in ungulates (20.4%) compared to carnivores (3.8%) and primates (3.4%). There were no significant differences in seroprevalence among sex and age ranges. The most frequent serovar detected was Autumnalis, present in 53.4% of antibody-positive animals. Most positive animals had titers of ≤1 : 200, except for a maned wolf ( Chrysocyon brachyurus ) with titers of 1 : 400 against serovar Hardjo. To the authors' knowledge, this is the first report of Leptospira exposure detected in native endangered pudu ( Pudu puda ) and the first confirmation of exposure to L. interrogans in captive wild mammals in Chile. Leptospirosis should be considered as a differential diagnosis in future disease presentation for hepatitis or abortions in captive mammals in Chile.

Genetic and phenotypic evidence of the Salmonella enterica serotype Enteritidis human-animal interface in Chile.

Salmonella enterica serotype Enteritidis is a worldwide zoonotic agent that has been recognized as a very important food-borne bacterial pathogen, mainly associated with consumption of poultry products. The aim of this work was to determine genotypic and phenotypic evidence of S. Enteritidis transmission among seabirds, poultry and humans in Chile. Genotyping was performed using PCR-based virulotyping, pulse-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Pathogenicity-associated phenotypes were determined with survival to free radicals, acidic pH, starvation, antimicrobial resistance, and survival within human dendritic cells. As result of PCR and PFGE assays, some isolates from the three hosts showed identical genotypic patterns, and through MLST it was determined that all of them belong to sequence type 11. Phenotypic assays show diversity of bacterial responses among isolates. When results were analyzed according to bacterial host, statistical differences were identified in starvation and dendritic cells survival assays. In addition, isolates from seabirds showed the highest rates of resistance to gentamycin, tetracycline, and ampicillin. Overall, the very close genetic and phenotypic traits shown by isolates from humans, poultry, and seabirds suggest the inter-species transmission of S. Enteritidis bacteria between hosts, likely through anthropogenic environmental contamination that determines infection of seabirds with bacteria that are potentially pathogenic for other susceptible organism, including humans.

Serotype-associated polymorphisms in a partial rpoB gene sequence of Salmonella enterica.

Salmonella enterica is a zoonotic bacterium with more than 2500 serotypes, which affect a wide range of hosts and produce diverse clinical outcomes. Strain identification usually involves costly and time-demanding procedures. This paper describes the sequencing of a rpoB hypervariable gene segment (847 bp) that allows identification of serotypes in S. enterica strains isolated from several hosts. The nucleotide similarity values among S. enterica serotypes ranged from 98.23% to 99.88%, with potential usefulness for devising a simple one-step sequencing as a first approach for identification of S. enterica strains. In conclusion, the analysis of polymorphisms in the partial rpoB sequence can discriminate S. enterica strains at the subspecies level.

Identification of diverse Salmonella serotypes, virulotypes, and antimicrobial resistance phenotypes in waterfowl from Chile.

Salmonella enterica is a pathogen with a wide host-range that presents great concern in developed and developing countries. To determine and characterize Salmonella strains found in Chile's waterfowl, we sampled 758 birds along 2000 km of the Chilean coast. In this sample, 46 isolates from 10 serotypes were detected, several with multidrug resistance phenotypes and different combinations of virulence-associated genes (virulotypes). These results suggest that Salmonella infection in waterfowl in Chile could have impacts on public and animal health.

[Possible association between Mycobacterium avium subsp paratuberculosis infection and Crohn's disease]. / Mycobacterium avium subsp paratuberculosis y enfermedad de Crohn: evidencias de una zoonosis.

Paratuberculosis is a chronic intestinal disease of animals caused by Mycobacterium avium subsp. paratuberculosis (MAP), which has some pathological features similar to Crohn's disease (CD) in humans. The presence of MAP in food for human consumption and in affected tissues of patients with CD has been detected. Therefore, a causal association between this microorganism and the disease in humans, has been postulated. However, several related studies have failed to confirm this hypothesis and the scientific acceptance of MAP as a zoonotic agent remains controversial. This review presents the main findings related to this issue, contrasting evidences for and against an association between MAP and CD. The need to promote national studies focusing on this area is suggested.

Host associated polymorphisms in the Corynebacterium pseudotuberculosis rpoB gene sequence.

Corynebacterium pseudotuberculosis is a widespread facultative intracellular pathogen that causes caseous lymphadenitis disease in sheep and goats, and generates cutaneous abscesses and granulomas in horses and cattle. Although some genes have been studied for diagnostic and phylogenetic analysis within the genus Corynebacterium, at subspecies level the pathogen has been poorly analyzed. The aim of this study was to characterize C. pseudotuberculosis strains isolated from domestic animals, through the sequencing of a hypervariable rpoB gene segment. As result, there were identified host associated rpoB polymorphisms in strains infecting sheep, goats and horses from Chile. These differences suggest the existence of bacterial genotypes, in which the nucleotide similarity values were ranging from 98.8 to 99.8%. In conclusion, the analysis of polymorphisms in the partial rpoB sequence can be used as a diagnostic tool that differentiates C. pseudotuberculosis strains at subspecies level.

Comparación del ensayo de interferón gamma bovino con técnicas tradicionales para el diagnóstico de infección con Mycobacterium bovis en la Región Metropolitana de Chile / Comparison of the bovine gamma-interferon assay with traditional techniques for detecting infection with Mycobacterium bovis

La tuberculosis bovina es una enfermedad infectocontagiosa de importancia económica y sanitaria en los planteles bovinos de países en desarrollo. La prueba cutánea de hipersensibilidad con derivadoproteico purificado (PPD) de M. bovis ha sido la técnica más ampliamente utilizada para su diagnóstico, aunque presenta deficiencias en sensibilidad y especificidad, además de requerir una segunda inspección del animal para su interpretación. Con el fin de superar estos problemas se ha desarrollado el ensayo de IFNγ bovino, que detecta la producción de esta citoquina por linfocitos del propio animal infectado. Diversos estudios han determinado que su eficiencia diagnóstica es similar a la prueba de tuberculina, pero ofrece la ventaja de requerir una sola manipulación del animal. El objetivo de este trabajo es comparar los resultados de un ensayo de IFNγ bovino (Bovigam® , CSL Ltd.,Melbourne, Australia) con tres técnicas tradicionales de diagnóstico, aplicadas generalmente en tejidos de animales beneficiados: examen post-mortem, tinción de Ziehl Neelsen y cultivo bacteriológico. Para ello, se eligieron un total de 142 muestras desde dos mataderos de la Región Metropolitana de Chile, consistentes en un trozo de ganglio mediastinal (20-40 gr) y sangre entera. Para confirmar el cultivo primario, se realizó una reacción en cadena de la polimerasa (PCR) para la amplificación de la secuencia de inserción (IS)1081, específica de las bacterias del complejo M. tuberculosis. Los resultados de las comparaciones solo indicaron diferencias significativas (p<0.01) entre las técnicas de cultivo bacteriológico y baciloscopía. En cuanto al nivel de concordancia, todas las pruebas demostraron valores significativos (p<0.01), aunque las mejores comparaciones se observaron entre las técnicas tradicionales. El ensayo de IFNγ detectó a solo cinco de nueve individuos con infección confirmada por bacterias del complejo M. tuberculosis y mostró reactividad con otros nueve animales....