Asymptomatic carriers of Babesia canis in an enzootic area. / Etude du portage asymptomatique de Babesia canis en zone d'enzootie.

Dogs latently infected with Babesia canis were systematically detected amongst a population kept in an enzootic area over a year. Detection of parasite was carried out on 43 healthy dogs and identified by two blood cultures in an interval of a few months. A serological study was performed using indirect immunofluorescence and Western blot. This study distinguished two distinct groups: asymptomatic carrier dogs (latently infected or premunised-33%) and non-carrier dogs with sterilising immunity. There is no difference between carrier and non-carrier dogs concerning age, breed or history of babesial infection and 36 out of the 43 dogs studied are seropositive. The antibody titer did not completely correlate with the detection of parasitaemia. All carrier dogs are seropositive to Babesia canis, but half of the seropositive dogs are not carriers. This study confirms that serological detection is not a good indicator of latent babesial infection. This study did not detect any difference between antibody responses (quantitative response (IIF) or qualitative response (WB)), related to latent parasitaemia.

Babesia canis: evidence for genetic diversity among isolates revealed by restriction fragment length polymorphism analysis.

The genetic diversity of B. canis was investigated by restriction fragment length polymorphism analysis. For this purpose, we identified a Babesia canis specific DNA probe named pS8. This 1.2 kbp probe can detect as low as 20 pg of B. canis DNA. Results suggest that the pS8 probe is distributed in multiple copies throughout the genome though is probably not itself internally repetitious, i.e. not structured into blocks of tandem units. This probe reveals discrete hybridizing fragments in B. canis enzyme-digested genomic DNA. RFLP patterns obtained with the pS8 probe revealed a large genetic diversity between various isolates and led us to distinguish several clones derived from a single isolate. Results suggest that for a single isolate, the fingerprints obtained reflect those of a few quantitatively dominant clones. This technique can now be routinely applied and provides a convenient tool for the characterization and the identification of B. canis isolates, strains and clones.

Prediction of preterm delivery: is it substantially improved by routine vaginal examinations?

The ability of routine vaginal examinations to improve the prediction of preterm delivery was assessed in a group of 6909 women who were registered at each prenatal visit and on whom this examination had been carried out. We compared two risk scores, one including known risk factors (maternal characteristics and symptoms reported by women), and the other including these factors and the findings of vaginal examination. These risk scores were computed by multiplying the adjusted odds ratio estimations obtained by logistic regressions. The prediction of preterm delivery was improved significantly by vaginal examination at 25 to 28 weeks' and 29 to 31 weeks' gestation. However, the improvement was not very large: when 30% of nulliparous women were classified as high risk at 29 to 31 weeks, the sensitivity was 55% when considering only the risk factors and 63% when adding the findings of vaginal examination; the percentages were 52% and 55%, respectively, for parous women. These results partially explain why the medical practice of routine vaginal examinations varies from country to country.

Can the number of cesarean sections be reduced without risk? An analysis of rates and indications in a university clinic.

This study concerns women followed from the first trimester of pregnancy, in a university clinic in Paris in 1977, 1979 and 1981. The cesarean section rate was separately analysed for primiparas, and multiparas with and without previous cesarean section. The overall rate of cesarean section was 11.4% in 1977, 17.2% in 1979 and 21.1% in 1981. The 9.6% increase observed between 1977 and 1981 is mainly attributable to an increase in primary cesarean section, particularly among primiparas, between 1977 and 1979. This does not seem to have arisen from sample variations. There is a change in obstetrical attitude and more cesarean sections are performed in cases of hypertension, breech presentation or intrauterine growth retardation. The greater number of previously sectioned women explains the increase in the rate between 1979 and 1981. The main fact among primiparas is the 18.8% increase in diagnosis of dynamic dystocia between 1979 and 1981. Three key areas allow us to envisage a reduction in cesarean section rate: obstetrical attitude towards previous cesarean section, breech presentation, and management of labor, whose perturbations lead to diagnosis of dynamic dystocia.

A comparison of two policies of ante-natal supervision for the prevention of prematurity.

The performance of 2 maternity units is compared. In comparable groups of average risk the prematurity rate was significantly lower in the unit practising intensive supervision during pregnancy.

A comparative study of the efficiency of hydroxyprogesterone caproate and of chlormadinone acetate in the prevention of premature labor.

The efficacy of caproate of hydroxyprogesterone and acetate of chlormadinone in preventing premature labore was compared in a controlled trial. The survey was based on 211 pregnant women with a high risk of premature delivery discovered during clinical examination. There are no significant differences between the two groups in either length of gestation, delay between the beginning of treatment and delivery or other parameters related to prematurity. The absence of evidence suggesting any significant difference between the two treatments can have three possible causes (which are discussed): the methodology, the inefficacy of the two products or the equivalent efficacy of the two products.