Public service deficiencies and Aedes aegypti breeding sites in Venezuela.

The 1992 study reported here assessed relationships between potable water supply and trash collection practices and the prevalence of dengue vector mosquito (Aedes aegypti) breeding sites in 30 towns located along the north coast of Venezuela. Within each study town, 100 homes were chosen. At each of these homes the number of water-bearing containers and containers harboring A. aegypti were determined and interviews were conducted to obtain information about the local water supply, trash collection services, and excreta disposal. In general, A. aegypti breeding indexes were high: 55% of the residences were found to harbor A. aegypti immature forms; there was an average of 118 breeding sites per 100 residences; and 24% of the water-bearing receptacles were observed to contain the mosquito. The statistical method of principal component analysis was employed to rank the 30 towns in terms of variables describing public service deficiencies, and correlations existing between the variables studied were determined. Direct correlations were found between two water supply variables (frequency and duration of water supply interruptions), between the excreta disposal and trash collection variables, between the duration of water supply interruptions and the Aedes breeding indexes, and between the duration of water supply interruptions and the mean number of A. aegypti breeding sites found in water storage containers. Overall, the towns with the poorest services were found to have the highest breeding indexes and the greatest numbers of water storage containers harboring the mosquito. It is concluded that public service (water supply and waste disposal) deficiencies were largely responsible for A. aegypti propagation in the study towns. Accordingly, it is recommended that local programs be implemented for recycling containers, constructing water storage tanks that cannot harbor Aedes larvae, and conducting health education and community participation campaigns directed against the mosquito.

Antenatal diagnosis of urinary tract abnormalities by ultrasonography after 28 weeks' gestation: incidence and outcome.

OBJECTIVE: The objective was to establish the likelihood that antenatal upper urinary tract dilatation identified after 28 weeks of gestation will progress to significant postnatal uropathy. STUDY DESIGN: In 5 years, 3856 fetuses had ultrasonography after 28 weeks of gestation when the mothers were first seen in advanced pregnancy for delivery appointments or for other obstetric indications. Fetuses with urinary tract anomalies had ultrasonographic surveillance after 6 days and 6 weeks of life with further evaluation as necessary. RESULTS: Renal tract anomalies were identified in 313 fetuses, and 55 infants had significant renal tract abnormalities. There were 7 deaths; 2 infants were anephric and 5 with hydronephrosis had lethal congenital abnormalities. Dilatation of the upper urinary tract was identified in 7.7% of the fetuses (298/3856) but was transient in 216 of them (72%). Follow-up of children with transient renal pelvis dilatation found only one with a history of urinary tract infection. Obstruction occurred in 23 infants (6.0/1000) and 16 required surgical correction. Vesicoureteric reflux was identified in 14 infants (3.6/1000) and resolved by age 2 years in 64%. Unilateral multicystic renal dysplasia occurred in 8 and posterior urethral valves occurred in 3 infants. CONCLUSION: Antenatal ultrasonography after 28 weeks' gestation identified significant renal tract abnormalities with a frequency of 14.3 per 1000 births, permitting early treatment of the asymptomatic newborn and reducing later renal damage.

Outcome after antenatal diagnosis of upper urinary tract dilatation by ultrasonography.

A prospective study was carried out during 1986 to find out the incidence of fetal renal tract anomalies in 3228 pregnant mothers delivered in one hospital. Ultrasound examination of the fetus was performed as part of the routine antenatal assessment at 16-20 weeks' gestation, and later examinations were done if there were obstetric indications. Fetuses with any degree of dilatation of the renal pelvis or other renal tract anomalies were followed up with serial ultrasound examinations in utero and then postnatally at 6 days and 6 weeks of age, or earlier if indicated. No renal tract anomalies were detected before 28 weeks' gestation, but of 761 fetuses examined later, 62 had dilatation of the renal pelvis not associated with overdistended bladders, and one fetus was anephric. After birth 10 of these infants (16%) were found to have pronounced renal tract abnormalities. Three who had associated serious congenital abnormalities died, five infants had obstruction of the pelviureteric junction, and two infants had vesicoureteric reflux. Antenatal ultrasonographic examination after 28 weeks identifed pronounced renal tract abnormalities in asymptomatic infants with a frequency of 9.2/1000 births (seven of 761) thus permitting early treatment and reducing the incidence of late complications.

Congenital hydrocephalus secondary to prenatal intracranial haemorrhage.

A high incidence of intracranial haemorrhage in utero of uncertain aetiology has been previously identified as an important cause of stillbirth in infants of immigrant Pacific Islanders in New Zealand. Congenital hydrocephalus is now described as a consequence of intracranial haemorrhage in 2 stillborn Pacific Islander infants. A large intracerebral haemorrhage, hydrocephalus and hydrops in one infant was first recognized prenatally by ultrasonography and caused intrauterine death at 26 weeks' gestation. Severe hydrocephalus in the other infant was first identified just before labour at term but the pathological findings were of old intraventricular haemorrhage with narrowing of the aqueduct of Sylvius as a reaction to the haemorrhage. Prior intracranial haemorrhage may be the cause of an increased incidence of hydrocephalus in Pacific Islander stillbirths and of some otherwise unexplained cases of congenital hydrocephalus in other races.

The effect of mild hyperventilation on red cell sodium.

Control subjects voluntarily overbreathed to produce end-tidal PCO2 levels similar to those found in patients suffering from neurotic or endogenous non-retarded depression. Red cell sodium content was found to decrease during overbreathing in all the subjects. The changes were similar to those usually reported for depressed patients. The results imply that red cell sodium levels are in part dependent on respiratory behaviour. They suggest a need for considerable caution in interpreting red cell sodium values from psychiatric patients.

Respiratory ventilation and carbon dioxide levels in syndromes of depression.

The breathing rate and PCO2 in end-tidal air have been studied in controls and in patients with endogenous depression (retarded and non-retarded), with neurotic depression, and with schizophrenia. It has been shown that breathing rate goes up and PCO2 down in non-retarded and neurotic depression. Schizophrenia gives more anomalous results. The fact is emphasized that such changes must lead to alterations in pH and other variables. Studies showing some small chemical differences between these clinical entities and control subjects might therefore be explained by these findings.