Cristobal Verdugo

Cristobal Verdugo
Universidad Austral de Chile · Instituto de Medicina Preventiva Veterinaria

Bachelor of Veterinary Science, MPVM, PhD

About

33
Publications
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Introduction
Associated Professor at the Preventive Veterinary Medicine Department of the Universidad Austral de Chile, Valdivia, Chile. His research has focused on the transmission dynamics of infectious pathogens in livestock and the assessment of diagnostic tests and surveillance systems for the detection of transmissible diseases.

Publications

Publications (33)
Article
Full-text available
Although a lack of diversity in genetic studies is an acknowledged obstacle for personalized medicine and precision public health, Latin American populations remain particularly understudied despite their heterogeneity and mixed ancestry. This gap extends to COVID-19 despite its variability in susceptibility and clinical course, where ethnic backgr...
Preprint
Full-text available
PURPOSE: Molecular mechanisms underlying COVID-19 susceptibility and severity are still poorly understood. The presence of genetic risk factors associated with ethnic background has been suggested, highlighting non-European ancestry as a risk factor for hospitalization in the United States. However, the representation of non-European populations in...
Article
Full-text available
The main objective of this study was to estimate the performance, under local epidemiological conditions, of two in-house ELISA assays for the combined detection of anti-SARS-CoV-2 IgA, IgM, and IgG immunoglobulins. A total of 94 serum samples were used for the assessment, where 44 corresponded to sera collected before the pandemic (free of SARS-Co...
Article
Full-text available
The objective was to evaluate the association between the severity of histopathological lesions caused by Mycobacterium avium subspecies paratuberculosis (MAP) infection and the molecular diversity of this pathogen. Blood, ileum, and mesenteric lymph node samples were collected at slaughter, from 1,352 adult cattle [source population 1 (SP1)]. In a...
Preprint
The main objective of this study was to estimate the performance, under local epidemiological conditions, of two in-house ELISA assays for the combined detection of anti-SARS-CoV-2 IgA, IgM, and IgG immunoglobulins. A total of 94 serum samples were used for the assessment, where 44 corresponded to sera collected before the pandemic (free SARS-CoV-2...
Article
Full-text available
One of the important routes of Mycobacterium avium subsp. paratuberculosis (MAP) transmission in dairy calves is milk. The aim of the present study was to assess the efficacy of milk treatments to prevent MAP infection transmission to calves. A one-year longitudinal study was carried out. Newborn calves were assigned to one of four experimental gro...
Article
Full-text available
Vibrio parahaemolyticus is the leading cause of seafood-associated bacterial gastroenteritis worldwide. Although different studies have focused on its pattern of variation over time, knowledge about the environmental factors driving the dynamics of this pathogen, within the Chilean territory, is still lacking. This study determined the prevalence o...
Article
Aims To estimate animal-level seroprevalence of Leptospira interrogans serovar Copenhageni and L. borgpetersenii serovars Ballum and Tarassovi, in beef cattle, sheep and deer on New Zealand farms, and herd/flock-level seroprevalence of any serovar when existing same-sera data for serovars Hardjobovis and Pomona were included, and to determine assoc...
Preprint
Full-text available
Background: The most important route of Mycobacterium avium subsp. paratuberculosis (MAP) transmission is fecal-oral and milk is an important vehicle for MAP transmission to dairy calves. The aim of the present study was to assess the efficacy of treatments for milk being fed to calves as a means of preventing MAP infection transmission. A one-year...
Preprint
Full-text available
Effective interventions are mandatory to control the transmission and spread of SARS-CoV-2, a highly contagious virus causing devastating effects worldwide. Cost-effective approaches are pivotal tools required to increase the detection rates and escalate further in massive surveillance programs, especially in countries with limited resources that m...
Article
The objective of this study was to estimate the performance of the peptide magnetic separation PCR test (PMS-PCR) for the diagnosis of Mycobacterium avium subsp. paratuberculosis (MAP) in sub-clinically infected dairy cattle. Twenty-one herds were randomly selected from a source population of 131 commercial dairy herds with a known history of MAP i...
Article
The objective of this study was to obtain diagnostic performance estimates for immunofluorescence antibody test (IFAT) and quantitative polymerase chain reaction (qPCR) tests, for Bacterial Kidney Disease (BKD) surveillance in farmed Atlantic salmon (Salmo salar) broodstock without signs compatible with the disease in Chile. To obtain diagnostic se...
Article
The study objective was to identify risk factors associated to: i) the infection by Mycobacterium avium subsp. paratuberculosis (MAP), and ii) paratuberculosis clinical incidence in Chilean dairy herds. A random sample of forty herds with previous history of MAP infection was selected. At herd level, all lactating cows were tested using a commercia...
Article
Full-text available
Paratuberculosis, a chronic disease affecting ruminant livestock, is caused by Mycobacterium avium subsp. paratuberculosis (MAP). It has direct and indirect economic costs, impacts animal welfare and arouses public health concerns. In a survey of 48 countries we found paratuberculosis to be very common in livestock. In about half the countries more...
Article
Full-text available
Aims: A major drawback of using dairy slurry as fertilizer is that it may contains pathogens such as Mycobacterium avium subsp. paratuberculosis (MAP), and it could represent a risk to animal and public health. Thus, the aim of this study was to evaluate the fate of MAP and bacterial communities in dairy slurry after chemical treatments. Methods...
Article
Estimation of the true prevalence of infected individuals involves the application of a diagnostic test to a population and adjusting according to test performance, sensitivity and specificity. Bayesian latent class analysis for the estimation of herd and animal-level true prevalence, has become increasingly used in veterinary epidemiology and is p...
Article
AIMS: To determine seroprevalence of Leptospira borgpetersenii serovar Hardjo and L. interrogans serovar Pomona in beef cattle, sheep and deer in New Zealand and the association between farm-level risk factors and seroprevalence. METHODS: Between June 2009 and July 2010, 20 serum samples per flock or herd were collected from 162 sheep flocks, and 1...
Article
This study aimed to estimate the distributions of the within-herd true prevalence (TP) and the annual clinical incidence proportion (CIp) of Mycobacterium avium subsp. paratuberculosis (MAP) infection in dairy cattle herds in Chile. Forty two commercial herds with antecedents of MAP infection were randomly selected to participate in the study. In s...
Article
Full-text available
In the Chilean coastal Patagonia, fourteen wild deer huemul faecal pellet samples were collected and cultured for Mycobacterium avium subsp. paratuberculosis detection. Six samples were positive, but only one was able to show a molecular type similar to the most common strain reported for cattle in Chile.
Article
Many developing countries lack sufficient resources to conduct animal disease surveillance. In recent years, participatory epidemiology has been used to increase the cover and decrease the costs of surveillance. However, few diagnostic performance assessments have been carried out on participatory methods. The objective of the present study was to...
Article
We examine two widely used treatment strategies for African animal trypanosomosis in West Africa: preventive drug control ex-ante trypanosomosis infection and curative drug control ex-post trypanosomosis infection. We investigate which combination of these alternative strategies is economically optimal for cattle farmers. We apply a dynamic optimis...
Article
A meta-analysis was performed to derive prevalence estimates for Brucella spp., Mycobacterium spp. and Trypanosoma spp. in cattle in Tanzania using data derived from a systematic review of zoonotic hazards in cattle production systems. Articles published before 2012 reporting prevalence and considered at least moderate in quality were included in t...
Article
The use of slurry as a fertilizer on grassland efficiently spreads infectious agents. Among those using the fecal– oral way of transmission, Mycobacterium avium subsp. Para tuberculosis (MAP) represents an interesting pathogen model to be studied in slurry management systems. In order to fulfill the requirements of a practical control implementatio...
Article
This study aimed to estimate the between- (HTP) and within- (TP) herd true prevalence distribution of Mycobacterium avium subsp. paratuberculosis (MAP) infection in dairy cattle herds participating in the Danish MAP control programme. All herds enrolled in the programme between 2011 and 2013 were included in the analysis, and one annual milk-ELISA...
Article
The study aimed to estimate the national- and island-level flock/herd true prevalence (HTP) of Mycobacterium avium subsp. paratuberculosis (MAP) infection in pastoral farmed sheep, beef cattle and deer in New Zealand. A random sample of 238 single- or multi-species farms was selected from a postal surveyed population of 1940 farms. The sample inclu...
Article
Full-text available
PCR represents a highly accurate means of confirming Mycobacterium avium subsp. paratuberculosis (Map) in broth culture. This study proposes a simple, efficient and low-cost method of harvesting DNA from Map cultured in liquid medium. The proposed method (UACH) was evaluated by comparing its performance against two traditional protocols (QIAamp and...
Article
Aim: To estimate the prevalence of Mycobacterium avium subsp. paratuberculosis (Map) in farmed deer with no gross post-mortem evidence of Map infection slaughtered in New Zealand, and to assess predictors of infection. Methods: Mesenteric lymph node (MLN) samples (n = 251) were collected from 60 lines of deer presented at two slaughterhouses in...
Article
This study aimed to develop a mathematical model describing the dynamics of paratuberculosis (PTB) in red deer (Cervus elaphus) under pastoral farming conditions in New Zealand. The model examined infectivity differences between ovine and bovine strains of Mycobacterium avium subspecies paratuberculosis (MAP) and seasonality of MAP survival. We als...
Article
The placement of sentinel birds in a commercial poultry flock infected with low pathogenic avian influenza virus (LPAIV) may be an effective way of detecting subsequent change in the isolate to a high pathogenic avian influenza virus (HPAIV). Data collected from the 2002 Chilean HPAIV outbreak, along with information from a literature review of lab...

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