Chlamydia trachomatis infection among Hispanic women in the California-Mexico border area, 1993: establishing screening criteria in a primary care setting.

BACKGROUND: Chlamydia prevalence and transmission patterns in California-Mexico border communities are unknown, and selective screening strategies for Hispanic populations have not been evaluated. GOAL OF THIS STUDY: To determine chlamydia prevalence among Hispanic women in the California-Mexico border area and established screening criteria. STUDY DESIGN: This was a cross-sectional prevalence survey of family planning/prenatal Hispanic clients (n = 2378) in San Diego and Imperial Counties, California, and Tijuana, Mexico. RESULTS: Overall, chlamydia prevalence was 3.2% (3.3% in California; 2.1% in Mexico). Women born in Mexico or those who visited Mexico for at least 1 week in the recent past had a prevalence rate similar to women without those characteristics. Multivariate analysis showed that young age (less than 25 years old), unmarried status, or having clinical signs of a chlamydia syndrome (primarily cervicitis) or vaginosis independently predicted chlamydia infection. Applying minimum screening criteria recommended by the Centers for Disease Control would require screening less than half of the clients. However, only 69% of infections would be identified. Using survey-based criteria (less than 25 years old, unmarried, and clinical signs of a chlamydia syndrome) would require screening 64% of clients, but would identify 92% of those infected. CONCLUSION: Chlamydia prevalence among Hispanic women seeking reproductive healthcare was similar (< 5%) on both sides of the California-Mexico border. Among Hispanic women, using easily obtained demographic data (age and marital status) and clinical signs (primarily cervicitis), an effective selective screening strategy can be implemented.

PIP: During January 1-October 15, 1993, three clinics in Imperial County, California, located east of the coastal mountain range which borders Baja California; a large community health center in San Diego County, California; and a public health/family planning clinic in Tijuana in Baja California, Mexico, successfully screened 2378 Hispanic women for Chlamydia trachomatis. The overall chlamydia prevalence was 3.2% (2.1% in Tijuana; 3.3% in California). Chlamydia was more common among the prenatal clients than family planning clients (4.7% vs. 2.6%; p 0.02). Adolescents had the highest chlamydia infection rate (7.5%). Women born in Mexico or those who visited Mexico for at least one week during the last three months had a similar chlamydia prevalence rate as those born in the US or those who had not visited Mexico recently. The multivariate analysis revealed that significant independent predictors of chlamydia infection included young age (25 years) (prevalence ratio [PR] = 4.5 for 20 years and 2.5 for 20-24 years), unmarried status (PR = 2), high risk sex behavior (PR = 1.1), exposure to a sexually transmitted disease (PR = 2.6), discharge/bleeding (PR = 1.4), vaginosis (PR = 3.6), and cervicitis (i.e., chlamydia syndrome) (PR = 6). If the clinics had applied the minimum screening criteria recommended by the US Centers for Disease Control, less than 50% of the clients would have been screened. Yet it would have identified only 69% of chlamydia infections. If clinics would apply the criteria identified in this survey, they would need to screen 64% of their clients, which would identify 92% of clients infected with chlamydia. These findings indicate that, in the California-Mexico border region, chlamydia prevalence among Hispanic women seeking reproductive health care was comparable. They also show that clinics can implement an effective selective screening strategy.

Epidemic dengue 1 in Brazil, 1986: evaluation of a clinically based dengue surveillance system.

In the last 15 years, dengue fever has emerged as a major health problem in tropical America. Prevention and control of epidemic disease are enhanced by the rapid identification of new or increased dengue activity. Most surveillance systems, however, identify cases by clinical case reports and, therefore, lack the sensitivity needed for early detection. During the 1986 dengue 1 epidemic in Rio de Janeiro, Brazil, the authors evaluated the usefulness of a clinical case definition by comparing it with laboratory-confirmed infection status of residents in two cities. The case definition had a sensitivity of 64% and a false-positive rate of 57%. Thus, for every 100 laboratory-confirmed dengue infections, 230 cases were reported. Both infected and noninfected residents who used medical services and who lived in the city with the highest transmission were more likely to meet the case definition. Thus, factors unrelated to actual infection influenced the sensitivity. With the use of stepwise logistic regression, the authors analyzed combinations of patient symptoms and produced nine new hypothetical case definitions. However, none of the new definitions had a false-positive rate lower than 38%. This study emphasizes the need for laboratory-based dengue surveillance systems.

An outbreak of influenza A/Taiwan/1/86 (H1N1) infections at a naval base and its association with airplane travel.

In late October 1986, an outbreak of influenza-like illness was detected at the Naval Air Station in Key West, Florida. Between October 10 and November 7, 1986, 60 active duty personnel reported experiencing a respiratory illness characterized by fever, cough, sore throat, and myalgia. Influenza A/Taiwan/1/86 (H1N1) virus was recovered from three symptomatic patients. Forty-one (68%) of 60 case-patients belonged to a 114-person squadron that had traveled to Puerto Rico for a temporary assignment from October 17-28, 1986. Among squadron members, the attack rate for persons previously vaccinated with the 1986-1987 trivalent influenza vaccine and for those unvaccinated was the same (37%). Transmission of infection among squadron personnel appeared to have commenced in Key West and continued in a barracks in Puerto Rico and aboard two DC-9 aircraft that transported the squadron back to Key West on October 28. There was no evidence that the outbreak spread to the surrounding civilian communities in Puerto Rico or Key West. This was the first reported outbreak of respiratory illness due to influenza A/Taiwan/1/86 (H1N1) in the continental United States in the 1986-1987 influenza season.

Hemolytic uremic syndrome and diarrhea associated with Escherichia coli O157:H7 in a day care center.

Three cases of hemolytic uremic syndrome with bloody diarrhea occurred during an outbreak of diarrheal illness in children aged 4 months to 9 years who attended a day care center. Thirty-six (34%) of 107 had diarrhea (three or more loose or watery stools in 24 hours) lasting greater than or equal to 3 days. Thirty-one (48%) of 64 children younger than 4 years of age but only (12%) of 43 in the older classes became ill (relative risk 4.0, P less than 0.001). Eleven (31%) of the 36 children with diarrhea had blood in their stools. Sequential movement of illness from class to class was consistent with person-to-person spread. Ten (18%) of 56 family members of ill children but only one of 45 family members of well children younger than 4 years of age developed a diarrheal illness (P less than 0.05). Escherichia coli O157:H7 was detected in two of eight stool specimens from children who had bloody diarrhea (one with hemolytic uremic syndrome), two of seven with nonbloody diarrhea, and none of nine who remained well. All three stool specimens obtained at less than or equal to 6 days compared with one of nine obtained at greater than 6 days after onset yielded this organism (P less than 0.02). E. coli O157:H7 can cause hemolytic uremic syndrome and both nonbloody and bloody diarrhea, and can spread within families and through modes other than foodborne transmission.

Imported measles outbreak in a university.

In 1981, a measles outbreak in an Arkansas university involved 16 students and four persons who were contacts of these students. The first two cases were in students who recently returned from Honduras. Of the 16 students with measles, 12 had significant gastrointestinal symptoms; five had elevated liver transaminase, and eight were hospitalized. Only two of the students were considered adequately immunized. A voluntary immunization clinic held on the university campus resulted in 67 per cent of 3,076 students being vaccinated.

Mitochondrial DNA variation in races of maize indigenous to Mexico.

Mitochondrial DNAs have been examined in accessions of 25 Mexican races of maize and compared with the mitochondrial DNAs previously found in inbred lines from the USA. Many variants were found. Low molecular weight DNA components, not previously found in US lines, were found in many of the accessions. Accessions classified as belonging to the same race, and plants from a single accession, sometimes had different mitochondrial genomes. Mitochondrial genomes similar to those in T and S cytoplasms were found in Mexican accessions.A low molecular weight linear DNA species has partial homology with a sequence in the high molecular weight mitochondrial genome. All plants with a shorter version of the linear molecule had a correspondingly altered region of homology in the high molecular weight genome.There is evidence that the geographical distribution of mitochondrial DNA types within Mexico is not random. One type, found in the oldest races, appears to be widely dispersed but another less common type appears to be confined largely to coastal regions. The potential value of these findings in maize breeding and for evolutionary studies is discussed.