Tuberculosis among Pennsylvania migrant farm workers.

The purpose of this study was to determine the tuberculin positivity rates and the incidence of sexually transmitted diseases (STDs) among a population of seasonal, nonmigrating farm workers. Participants were tested for tuberculosis (TB) sensitivity, syphilis, gonorrhea, and chlamydia. Patients were afforded follow-up even if they returned home to Mexico during the course of their treatment. We found that the TB rate (15%) and the incidence of STDs to be significantly lower than in other studies of migrant populations. We hypothesize that exposure to urban commercial sex workers who frequent many migrant camps may be involved in the transmission of TB. Further research is needed to determine the incidence of TB among commercial sex workers and the extent to which transmission occurs between these two populations. We also describe our follow-up program and recommend a closer adherence to the Centers for Disease Control and Prevention guidelines with respect to adequate health education and disease prevention.

Prevalence of Chlamydia trachomatis infection in pregnant patients.

Chlamydia is a sexually transmitted disease of epidemic proportions, infecting an estimated 4 million people a year. It results not only in infertility and ectopic pregnancy but also in infant morbidity and mortality. Ectopic pregnancy is responsible for 11 percent of maternal deaths. About 60 percent of infected women can transmit the bacteria at birth to their infants. Early detection and treatment of chlamydia in both men and women, especially prenatal women, is critical. Chlamydia trachomatis infection of the cervix was found in 8.1 percent of a group of 1,004 pregnant women at a hospital prenatal clinic by means of a direct fluorescent antibody test. The prevalence of C. trachomatis was only 0.7 percent in 277 pregnant women receiving prenatal care from private practitioners. All patients between 27 and 30 weeks gestation who tested positive were treated with oral erythromycin. Their partners were treated with tetracycline. The outcome of pregnancy in patients treated for chlamydial infection was compared with a control group of noninfected mothers from the same population. The frequency of premature rupture of the membranes, prematurity, and low Apgar scores among the treated women were not significantly different from those in the control group. There was a significant difference, however, between the two groups in the incidence of low mean birth weight infants and the presence of meconium. Children can acquire a chlamydial infection at birth from contact with infected cervico-vaginal secretions. If not detected and treated, these infected infants may develop conjunctivitis, bronchiolitis, and pneumonia. It is suggested, therefore, that all patients at prenatal clinics be screened for chlamydial cervicitis. Those testing positive and their partners should be treated.

Purification and characterization of epizootic diarrhea of infant mice virus.

Epizootic diarrhea of infant mice virus has been purified from the intestines of infected mice using enzymatic digestion, precipitation with polyethylene glycol, extraction with Genesolv-D, and sucrose step-gradient centrifugation. The purified virus was found to be stable at -70 C or when treated with ether, chloroform, or sodium deoxycholate. Biochemical analysis of purified virions has suggested that the nucleic acid type of epizootic diarrhea of infant mice virus was of the ribonucleic acid type. Preparations of purified virions stained with phosphotungstic acid showed a particle with icosahedral symmetry, 54 +/- 2 nm in diameter and probably composed of 32 hollow capsomeres.