Gustavo Monti

European Hares in Chile: A Different Lagomorph Reservoir for Mycobacterium avium subsp. paratuberculosis?

Ruminants are the principal host for infection by Mycobacterium avium subsp. paratuberculosis (Map), the cause of Johnes disease. Based on studies of a Map-infected population of European rabbits (Oryctolagus cuniculus) in Scotland, lagomorphs as a broad taxonomic order were proposed as potential nonruminant reservoirs for Map. To determine whether a different lagomorph species may serve as a wildlife reservoir, we investigated Map infection in European hares (Lepus europaeus) sharing habitat with known Map-infected dairy cattle in southern Chile. Fecal, mesenteric lymph node, and ileal samples were aseptically collected from 385 wild hares for liquid culture and real-time polymerase chain reaction identification of acid-fast isolates. All tissue samples were also acid-fast stained and examined microscopically. We isolated Map from at least one tissue from 48 hares (12.6%) and fecal samples from 16 hares (4.2%). No Map was found in tissues of eight of the fecal-culture–positive hares. Histologically, all tissues from all hares were within normal limits, and no acid-fast organisms were observed in any sample. Active infection, implying amplification of the organism secondary to resultant disease, was not evident. With this report Map isolations on a population versus incidental detection have now been made from two lagomorph species. However, although the rabbit population studied in Scotland appears to function as a Map reservoir, the hares studied in Chile appear to be a dead-end host, serving only as potential mechanical vectors for the organism.

Herd-level prevalence of Map infection in dairy herds of southern Chile determined by culture of environmental fecal samples and bulk-tank milk qPCR.

Paratuberculosis, an infectious disease of domestic and wild ruminants caused by Mycobacterium avium subsp. paratuberculosis (Map), is an economically important disease in dairy herds worldwide. In Chile the disease has been reported in domestic and wildlife animals. However, accurate and updated estimations of the herd-prevalence in cattle at national or regional level are not available. The objectives of this study were to determine the herd-level prevalence of dairy herds with Map infected animals of Southern Chile, based on two diagnostic tests: culture of environmental fecal samples and bulk-tank milk qPCR. Two composite environmental fecal samples and one bulk-tank milk sample were collected during September 2010 and September 2011 from 150 dairy farms in Southern Chile. Isolation of Map from environmental fecal samples was done by culture of decontaminated samples on a commercial Herrolds Egg Yolk Medium (HEYM) with and without mycobactin J. Suspicious colonies were confirmed to be Map by conventional IS900 PCR. Map detection in bulk-tank milk samples was done by real time IS900 PCR assay. PCR-confirmed Map was isolated from 58 (19.3%) of 300 environmental fecal samples. Holding pens and manure storage lagoons were the two more frequent sites found positive for Map, representing 35% and 33% of total positive samples, respectively. However, parlor exits and cow alleyways were the two sites with the highest proportion of positive samples (40% and 32%, respectively). Herd prevalence based on environmental fecal culture was 27% (true prevalence 44%) compared to 49% (true prevalence 87%) based on bulk-tank milk real time IS900 PC. In both cases herd prevalence was higher in large herds (>200 cows). These results confirm that Map infection is wide spread in dairy herds in Southern Chile with a rough herd-level prevalence of 28-100% depending on the herd size, and that IS900 PCR on bulk-tank milk samples is more sensitive than environmental fecal culture to detect Map-infected dairy herds.

Economic effect of bovine abortion syndrome in commercial dairy herds in Southern Chile.

Bovine abortion is a limiting factor for dairy business, as it decreases milk production and the potential, number of herd replacements, increases feeding and medical treatment costs, increases the number of artificial inseminations to obtain a calf as well as culling rates of cows. An estimation of the economic impact of abortion in dairy farms in Chile is not available yet. The aim of this study was to estimate the economic consequences of bovine abortion syndrome (BAS) in dairy cows from Chile. A stochastic model was proposed to evaluate the cost of an abortion on a yearly basis to include variability in cost and income by dairy and by year. The marginal total net revenue (ΔTNR) for a typical, lactation was obtained by the calculating the difference between total revenues (retail milk and calf sales) and total expenses (production cost (cows, feeding, labor, health) plus administrative and, general costs) for lactation with and without abortion. Production data were obtained from a retrospective study of 127 dairy herds located in southern Chile between 2000 and 2006. Milk production from cows with and without abortion was estimated by a mixed model using milk test day data. Production cost and prices paid to farmers were obtained from service company records (TODOAGRO S.A.). Cost and income value was corrected for inflation and expressed in the values from 2006. In addition, a separate analysis for different parities (1, 2, 3 or more) was performed. Distributions for the stochastic variables were obtained by fitting distributions from our database using @Risk. The stochastic variables included in the analysis were all related to income, feeding, depreciation, health, Artificial Insemination and general costs like fuel, salaries, taxes, etc. There was a high probability (89.20%) of a negative ΔTNR in lactations with abortion for overall, parities, with a mean loss of

Association between cattle herd Mycobacterium avium subsp. paratuberculosis (MAP) infection and infection of a hare population

-143.32. Stratifying by parity, the predicted mean of the distribution for ΔTNR in each parity (1, 2, 3 or more) was also negative and the probability of a negative ΔTNR was 89.40%, 95.30% and 97.00%, respectively, but differs between them (p<0.05). For parity 1, mean ΔTNR was

Leptospirosis in dogs and cats: epidemiology, clinical disease, zoonotic implications and prevention

-120.92, parity 2

Risk factors for Mycobacterium avium subsp. paratuberculosis (MAP) and Mycobacterium bovis coinfection at individual animal level in southern Chile cattle populations

-116.35 and for parities ≥3 it was

Effect of Mycobacterium avium subsp. paratuberculosis (MAP) infection on the diagnostic accuracy for Mycobacterium bovis ( M. bovis ) infection under field conditions in cattle belonging to low M. bovis prevalence herds

-132.26 and the mean was statistically different from the others (p<0.05). The age of culled cows was the input variable most correlated with TNR and dairy production was the second. However, the sale price of milk resulted in a low correlation with abortion cost.

Risk factors for infectious pancreatic necrosis in farmed Chilean Atlantic salmon ( Salmo salar L.) from 2010 to 2013

Paratuberculosis has long been considered a disease of domestic and wild ruminants only. The known host range of Mycobacterium avium subsp. paratuberculosis (MAP) was recently extended to include non-ruminant wildlife species believed to be exposed to spillover of MAP from infected domestic cattle herds. The aim of the present study was to assess the association between cattle herd MAP infection pressure level and the infection level of a hare population in two dairy farms of southern Chile. Fifty hares from a herd A and 42 hares from herd B were captured and sampled for MAP culture. The results showed a statistically significant association between the cattle herds’ infection prevalence and the hare infection prevalence.

Evidence of interspecies transmission of pathogenic Leptospira between livestock and a domestic cat dwelling in a dairy cattle farm

La leptospirosis es una enfermedad zoonotica de distribucion mundial causada por espiroquetas del genero Leptospira . Este genero incluye numerosos serovares que pueden ser eliminados en grandes cantidades en la orina de los animales infectados formando una importante fuente de infeccion. Muchas especies de mamiferos domesticos y silvestres son hospedadores de mantencion constituyendo los reservorios de la bacteria y otras especies actuan como hospedadores incidentales que pueden desarrollar la enfermedad. En caninos y felinos la enfermedad es causada por diferentes serovares y los caninos actuan como hospedadores de mantencion para algunos serovares y ambas especies son huespedes incidentales para otros. Como perros y gatos pueden tener contacto frecuente con animales silvestres y de granja, constituyen una importante conexion en la transmision. Las leptospiras pueden sobrevivir en el ambiente, lo que agrega complejidad a la epidemiologia de la infeccion. La presentacion de la enfermedad es muy variable y en particular la informacion sobre leptospirosis en felinos es limitada. Las pruebas de laboratorio son esenciales para el diagnostico de la enfermedad, pero existen dificultades para discriminar entre la infeccion por Leptospira en pacientes con enfermedad clinica de la respuesta inmune especifica de anticuerpos leptospirales tanto en los hospedadores de mantencion como en animales con infeccion subclinica. La infeccion en mascotas puede tener importantes implicaciones economicas y de salud publica y debido al riesgo de transmision de la enfermedad hacia los propietarios y otros animales, es necesario aplicar medidas de prevencion

Comparison of common tests performance for Mycobacterium bovis infection diagnosis in low prevalence dairy cattle herds of southern Chile

Mycobacterium avium subsp. paratuberculosis (MAP) causes a chronic intestinal infection mainly in domestic and wild ruminants and is transmitted primarily by the fecal-oral route. Mycobacterium bovis (M. bovis) produces a chronic infection principally of the respiratory system. It affects most domestic mammals, wild species, and humans and is spread via the respiratory or oral route. It is important to note that M. bovis is considered a major zoonotic agent. The term coinfection refers to the coexistence of two or more infectious agents in the same host. The goal of the present study was to assess management factors that may favor coinfection with MAP and M. bovis in cattle at an individual level. A cross-sectional study was conducted including 366 cattle from 11 herds. Diagnostic information for both pathogens and individual characteristics of the animals and management practices applied on them was collected from each herd. The results indicated a set of variables being more frequent in the coinfected group of animals and mainly related with biosecurity measures. This study provided regionally based data that may be used to design future control plans for both cattle infections in southern Chile.