In vitro development of murine embryos in presence of campylobacter fetus / Desarrollo de embriones murinos in vitro en presencia de campylobacter fetus

Bovine campylobacteriosis caused by Campylobacter fetus is associated with reproductive losses. The knowledge about the mechanisms of bacterial pathogenesis is limited, then a murine experimental model is proposed. BALB/c females and males were used. Two-cell embryos were cultured in Ham-F10 as control group (CG). Treatment groups were constituted by the addition of Cfv 1 and 3, or Cff 2 and 5. Morulae were placed in Ham-F10 (CG); treatment groups were constituted by the addition of Cfv27, CFF (cell-free filtrate) and Brucella broth (BB). Blastocysts were cultured in MEM (CG); challenge group were constituted by the addition of Cfv 27. Differentiation, hatching, hatched, adhesion and expansion were evaluated. Results were analyzed by Chi2 test. In two-cell embryo, the differentiation rate was not modified when the study strains were added (p > 0.05). The differentiation rate at 24 h for embryos at the morula stage was lower for BB, Cfv, and CFF, compared with CG (p < 0.05). After 48 h culture, no differences were observed in blastocyst formation for Cfv and BB, compared to CG (p > 0.05). However, the differentiation rate for the CFF group was lower than for CG (p < 0.05). At 48 and 72 h, the hatching rate was higher in CFF and Cfv groups than in CG (p < 0.05). Differences were not detected in blastocyst cultures. In conclusion, under these experimental conditions, Cf was not detrimental to the development of murine embryos. Efforts will be intensified to establish in vitro infection models that reproduce their pathogenicity.

La campilobacteriosis bovina caudada por Campylobacter fetus produce pérdidas reproductivas existiendo poca información de los mecanismos de patogenicidad de dicha bacteria, por lo cual se propone un modelo utilizando ratones BALC/c. Embriones de dos células fueron cultivados en Ham-F10: grupo control (GC), los grupos experimentales fueron adicionados con las cepas Cfv 1, Cfv 3, Cff 2 y Cff 5. Mórulas fueron cultivadas en Ham-F10 (GC); los grupos tratados recibieron Cfv27, CFF (filtrado libre de células) y caldo Brucella (BB). Blastocistos fueron cultivados en MEM (GC) y MEM más Cfv 27 (grupo desafiado). Se evaluó: diferenciación, "hatching", "hatched", adhesión y expansión. Los resultados fueron analizados por Chi2. En embriones de dos células, la diferenciación no fue modificada por acción de las cepas evaluadas (p > 0,05). Para embriones en estadío de mórula, la diferenciación a las 24 h de cultivo fue menor para BB, Cfv, y CFF, comparado con el GC (p < 0,05). Luego de 48 h de cultivo, no hubo diferencias entre Cfv, BB, y CG (p > 0,05), no obstante para el grupo CFF la diferenciación fue menor al CG (p < 0,05). El porcentaje de "hatching" (48 y 72 h de cultivo), fue mayor en los grupos CFF y Cfv comparado con el GC (p < 0,05). La adición de Cfv 27 no modificó el desarrollo de blastocistos. En el modelo propuesto, Cf no afectó negativamente el desarrollo embrionario. Futuros trabajos serán necesarios para establecer un modelo de infección in vitro en pos de reproducir su patogenicidad.

Search for the genome of bovine herpesvirus types 1, 4 and 5 in bovine semen.

Bovine herpesvirus type 1 (BoHV-1) causes respiratory and reproductive disorders in cattle. Recently, bovine herpesvirus type 5 (BoHV-5) and bovine herpesvirus type 4 (BoHV-4) have been identified to be associated with genital disease. In this study, the presence of the genome of BoHV-1, BoHV-4 and BoHV-5 in bovine semen of Argentinean and international origin was analyzed by PCR assays. The most important finding of this study is the detection of the genome of BoHV-1 and BoHV-4 in semen of bulls maintained at artificial insemination centers. It is particularly relevant that BoHV-1 DNA was also identified in one sample of international origin suggesting the need for extensive quality control measures on international transport of bovine semen.

Histological and lectin binding changes in the genital tract of mice infected with Tritrichomonas foetus.

An experimental murine model of bovine genital tritrichomonosis is described. Female mice were inoculated per vaginam with Tritrichomonas foetus and a sample of the study population was killed every 3 days up to 60 days post-infection. Microscopical changes in the reproductive organs were assessed and immunohistochemistry was used to detect T. foetus within these tissues. Lectin histochemistry was used to determine changes in the expression of carbohydrates within the reproductive mucosa. A range of microscopical changes were detected in the uterine endometrium by 10 days post-inoculation and these were associated with the presence of the protozoan. The endometrial changes included endometritis and ulceration, mucosal atrophy and glandular metaplasia, and were similar to those reported in naturally infected cows. Changes in lectin binding were recognized first in the vagina where there was increased binding of Ulex europaeus agglutinin-1 (UEA-1) which was maximal on day 16 post-inoculation. Within the uterus, there was increased binding of soy bean agglutinin (SBA) which was maximal on day 19 post-inoculation, and of peanut agglutinin (PNA) which was maximal on day 16 post-inoculation. These changes in carbohydrate expression parallel the infection kinetics, since they appeared first in the vagina and later in the uterus. The changes may reflect either a host reaction against the infection or the production of enzymes by T. foetus, which act to enhance adhesion and colonization of the genital organs by the organism. The kinetics and pathogenesis of this murine infection are similar to those of the natural bovine disease, suggesting that this model system may be valuable for further studies of this disease.

Interaction of Tritrichomonas foetus with the reproductive tract of experimentally infected female BALB/c mice: ultrastructural evaluation.

The interaction of Tritrichomonas foetus with its host is a complex process that involves colonisation, attachment and persistence. The goal of the present study was to describe the interaction of T. foetus with the genital tract using a model of non-oestrogenised female BALB/c mice which had been intravaginally infected with a suspension of T. foetus during oestrus. Animals were sacrificed after 10 weeks and the uteri fixed and processed for light and electron microscopy. Ultrastructural analysis showed that the attached protozoa interacted with the mucosa through a somal projection. With an amorphous secretion at the protozoa-host cell interface. There was no direct contact between the protozoal plasma membrane and the epithelial cell membrane. Our results demonstrated the participation of an active phagocytosis and the destruction of T. foetus by eosinophils.

[Presentation of salmonellosis in the Tandil district, Argentina]. / Presentación de salmonelosis en el partido de Tandil, Argentina.

From January 1990 to July 1992 a prospective study on the salmonellosis form of presentation, reservoirs and transmission in Tandil was carried out. Forty strains of Salmonella enterica were isolated with the following distribution: 28 humans (17 children and 11 adults), 6 in foods (1 in raw milk, 3 in well water, 1 in home made mayonnaise and 1 in chicken salad) and 6 in animals (1 in cow, 2 in chicken and 2 in calves). Salmonella Enteritidis was the most frequent isolate. Disease was evident only in a few susceptible hosts and the epidemiological chain could not be determined in all the cases.

Presentación de salmonelosis en el partido de Tandil, Argentina / [Presentation of salmonellosis in the Tandil district, Argentina]

From January 1990 to July 1992 a prospective study on the salmonellosis form of presentation, reservoirs and transmission in Tandil was carried out. Forty strains of Salmonella enterica were isolated with the following distribution: 28 humans (17 children and 11 adults), 6 in foods (1 in raw milk, 3 in well water, 1 in home made mayonnaise and 1 in chicken salad) and 6 in animals (1 in cow, 2 in chicken and 2 in calves). Salmonella Enteritidis was the most frequent isolate. Disease was evident only in a few susceptible hosts and the epidemiological chain could not be determined in all the cases.

Presentación de salmonelosis en el partido de Tandil, Argentina. / [Presentation of salmonellosis in the Tandil district, Argentina]

From January 1990 to July 1992 a prospective study on the salmonellosis form of presentation, reservoirs and transmission in Tandil was carried out. Forty strains of Salmonella enterica were isolated with the following distribution: 28 humans (17 children and 11 adults), 6 in foods (1 in raw milk, 3 in well water, 1 in home made mayonnaise and 1 in chicken salad) and 6 in animals (1 in cow, 2 in chicken and 2 in calves). Salmonella Enteritidis was the most frequent isolate. Disease was evident only in a few susceptible hosts and the epidemiological chain could not be determined in all the cases.