Medical examiner samples: a source for dengue surveillance

Post-mortem medical examiner samples may be useful for sentinel surveillance of disorders usually detected by antibody determinations on specimens from ill patients or from surveys. We found anti-dengue IgM positivity in 3(23/780) and anti-dengue IgG positivity in 77(597/777) of sera obtained at the Puerto Rico medical examiner (Institute of Forensic Sciences) in December 2000, April 2001, and October 2001. This approach may be a useful alternative for estimating the population prevalence of serologic markers for dengue and other infectious diseases.

Transmission thresholds for dengue in terms of Aedes aegypti pupae per person with discussion of their utility in source reduction efforts.

The expense and ineffectiveness of drift-based insecticide aerosols to control dengue epidemics has led to suppression strategies based on eliminating larval breeding sites. With the notable but short-lived exceptions of Cuba and Singapore, these source reduction efforts have met with little documented success; failure has chiefly been attributed to inadequate participation of the communities involved. The present work attempts to estimate transmission thresholds for dengue based on an easily-derived statistic, the standing crop of Aedes aegypti pupae per person in the environment. We have developed these thresholds for use in the assessment of risk of transmission and to provide targets for the actual degree of suppression required to prevent or eliminate transmission in source reduction programs. The notion of thresholds is based on 2 concepts: the mass action principal-the course of an epidemic is dependent on the rate of contact between susceptible hosts and infectious vectors, and threshold theory-the introduction of a few infectious individuals into a community of susceptible individuals will not give rise to an outbreak unless the density of vectors exceeds a certain critical level. We use validated transmission models to estimate thresholds as a function of levels of pre-existing antibody levels in human populations, ambient air temperatures, and size and frequency of viral introduction. Threshold levels were estimated to range between about 0.5 and 1.5 Ae. aegypti pupae per person for ambient air temperatures of 28 degrees C and initial seroprevalences ranging between 0% to 67%. Surprisingly, the size of the viral introduction used in these studies, ranging between 1 and 12 infectious individuals per year, was not seen to significantly influence the magnitude of the threshold. From a control perspective, these results are not particularly encouraging. The ratio of Ae. aegypti pupae to human density has been observed in limited field studies to range between 0.3 and >60 in 25 sites in dengue-endemic or dengue-susceptible areas in the Caribbean, Central America, and Southeast Asia. If, for purposes of illustration, we assume an initial seroprevalence of 33%, the degree of suppression required to essentially eliminate the possibility of summertime transmission in Puerto Rico, Honduras, and Bangkok, Thailand was estimated to range between 10% and 83%; however in Mexico and Trinidad, reductions of >90% would be required. A clearer picture of the actual magnitude of the reductions required to eliminate the threat of transmission is provided by the ratio of the observed standing crop of Ae. aegypti pupae per person and the threshold. For example, in a site in Mayaguez, Puerto Rico, the ratio of observed and threshold was 1.7, meaning roughly that about 7 of every 17 breeding containers would have to be eliminated. For Reynosa, Mexico, with a ratio of approximately 10, 9 of every 10 containers would have to be eliminated. For sites in Trinidad with ratios averaging approximately 25, the elimination of 24 of every 25 would be required. With the exceptions of Cuba and Singapore, no published reports of sustained source reduction efforts have achieved anything near these levels of reductions in breeding containers. Practical advice on the use of thresholds is provided for operational control projects.

Transmission thresholds for dengue in terms of Aedes aegypti pupae per person with discussion of their utility in source reduction efforts

The expense and ineffectiveness of drift-based insecticide aerosols to control dengue epidemics has led to suppression strategies based on eliminating larval breeding sites. With the notable but short-lived exceptions of Cuba and Singapore, these source reduction efforts have met with little documented success; failure has chiefly been attributed to inadequate participation of the communities involved. The present work attempts to estimate transmission thresholds for dengue based on an easily-derived statistic, the standing crop of Aedes aegypti pupae per person in the environment. We have developed these thresholds for use in the assessment of risk of transmission and to provide targets for the actual degree of suppression required to prevent or eliminate transmission in source reduction programs. The notion of thresholds is based on 2 concepts: the mass action principal-the course of an epidemic is dependent on the rate of contact between susceptible hosts and infectious vectors, and threshold theory-the introduction of a few infectious individuals into a community of susceptible individuals will not give rise to an outbreak unless the density of vectors exceeds a certain critical level. We use validated transmission models to estimate thresholds as a function of levels of pre-existing antibody levels in human populations, ambient air temperatures, and size and frequency of viral introduction. Threshold levels were estimated to range between about 0.5 and 1.5 Ae. aegypti pupae per person for ambient air temperatures of 28 degrees C and initial seroprevalences ranging between 0% to 67%. Surprisingly, the size of the viral introduction used in these studies, ranging between 1 and 12 infectious individuals per year, was not seen to significantly influence the magnitude of the threshold. From a control perspective, these results are not particularly encouraging. The ratio of Ae. aegypti pupae to human density has been observed in limited field studies to range between 0.3 and >60 in 25 sites in dengue-endemic or dengue-susceptible areas in the Caribbean, Central America, and Southeast Asia. If, for purposes of illustration, we assume an initial seroprevalence of 33%, the degree of suppression required to essentially eliminate the possibility of summertime transmission in Puerto Rico, Honduras, and Bangkok, Thailand was estimated to range between 10% and 83%; however in Mexico and Trinidad, reductions of >90% would be required. A clearer picture of the actual magnitude of the reductions required to eliminate the threat of transmission is provided by the ratio of the observed standing crop of Ae. aegypti pupae per person and the threshold. For example, in a site in Mayaguez, Puerto Rico, the ratio of observed and threshold was 1.7, meaning roughly that about 7 of every 17 breeding containers would have to be eliminated. For Reynosa, Mexico, with a ratio of approximately 10, 9 of every 10 containers would have to be eliminated. For sites in Trinidad with ratios averaging approximately 25, the elimination of 24 of every 25 would be required. With the exceptions of Cuba and Singapore, no published reports of sustained source reduction efforts have achieved anything near these levels of reductions in breeding containers. Practical advice on the use of thresholds is provided for operational control projects.

Is cyclic vomiting syndrome related to migraine?

OBJECTIVE: To examine the overlap between cyclic vomiting syndrome (CVS) and migraine by comparing 2 subsets of children with migraine-associated and non-migraine-associated CVS. METHODS: We studied all children <18 years of age who met the consensus criteria for CVS after presentation to our pediatric gastroenterology service from 1986 to 1998. The clinical patterns and responses to treatment were obtained from a combination of chart reviews and structured interviews. RESULTS: Among 214 children identified as having CVS, 82% were classified as having migraine-associated CVS based on 1 of 2 criteria either a family history of migraines or subsequent development of migraine headaches. Compared with the non-migraine CVS subgroup, the migraine subset had milder episodes (20.7 27.3 SD vs 39.5 66.5 emeses/episode, P =.006); more symptoms of abdominal pain (83% vs 66%), headache (41% vs 24%), social withdrawal (40% vs 22%), photophobia (36% vs 16%, all P <.05); more frequent triggering events (70% vs 49%, P =.013) including psychologic stress (39% vs 22%), physical exhaustion (23% vs 3%), and motion sickness (10% vs 0%); and a higher positive response rate to anti-migraine therapy (79% vs 36%, P =.002). CONCLUSIONS: The majority of children with CVS were subclassified as having migraine-associated CVS. The migraine-associated subgroup had less severe vomiting, manifested symptoms typical of migraine headaches, and had higher response rates to anti-migraine therapy. These findings strengthen the relationship between migraine and CVS.

Insecticide susceptibility of Aedes aegypti and Aedes albopictus in the Lower Rio Grande Valley of Texas and Mexico.

In response to a potential dengue fever outbreak in south Texas during 1995, the susceptibilities of Aedes aegypti and Aedes albopictus to commonly used mosquito adulticides were assessed. Larvae collected from the Lower Rio Grande Valley of Texas and Mexico were reared to adults and tested against susceptible laboratory strains at Texas A&M University. Resistance ratios at both the LC50 and LC95 rates were all less than 10, indicating that adult populations of both species are still susceptible to malathion, chlorpyrifos, resmethrin, and permethrin.

[Advances in the treatment of tachiarrhythmias: role of nonpharmacological methods]. / Avances en el tratamiento de las taquiarritmias: rol de los métodos no farmacológicos.

Nonpharmacological methods are a novel therapeutic option for tachiarrhythmias. Transcatheter ablation or surgery can cure many arrhythmias, avoiding the collateral effects of antiarrhythmic drugs. Likewise, implantable defibrillators, have changed life expectancy of patients with high risk arrhythmias or sudden death survivors. However, the high cost and sophistication of these methods, preclude their widespread use, thus limiting the number of patients that can be benefited. This article reviews the main nonpharmacological techniques for treatment of arrhythmias, their results and complications.

Triangulation in cross-cultural research of child development in Jamaica.

PIP: Triangulation is the use of multiple concepts and methods to study a single phenomenon. Ethnographic field studies and standardized measures of development were used in a study of long-term effects of perinatal cannabis (marijuana) use in Jamaica. The study was launched in 1983 in order to evaluate the effects of cannabis (or ganja, as it is called in Jamaica) consumption during pregnancy and lactation on infants from birth to school age in rural communities. Some researchers reported symptoms such as increased startles, high-pitched cry in the newborn, shortened gestation, and low birth weight. The project was based in St. Thomas, where ganja use is widespread. The ethnographic part involved home observations and interviews of each child in selected communities. The clinical component included monitoring 60 pregnant women (30 users and 30 nonusers) and their offspring from birth through age 5. The instruments for evaluation included the Brazelton Neonatal Assessment Scale (BNAS), the Bayley Scales of Infant Development (BSID), the McCarthy Scales of Children's Abilities (MSCA, for children aged 2 years 6 months to 8 years 6 months), and the Behavioral Style Questionnaire (BSQ, for temperament in 3 to 7 year olds). The MSCA and BSQ had to be adapted to local culture, partly because of different uses of words in the rural dialect and cultural experience. The MSCA modifications included the elimination of time limits, changes in language, and culturally correct alternative responses. Five of 72 items on the BSQ were modified. Most scores fell in the middle range of about 4, similar to the North American scores, except for the lower mean in the category of Threshold of Responsiveness, because of an unanticipated cultural difference. The adjustments made did not compromise the comparability of the findings.^ieng

Five-year follow-up of rural Jamaican children whose mothers used marijuana during pregnancy.

This research provides data on the development of 59 Jamaican children, from birth to age 5 years, whose mothers used marijuana during pregnancy. Approximately one-half of the sample used marijuana during pregnancy and were matched with non-users according to age, parity, and socioeconomic status. Testing of the children was done at 1, 3, and 30 days of age with the Brazelton Neonatal Behavioral Assessment Scales and at ages 4 and 5 years with the McCarthy Scales of Children's Abilities. Data about the child's home environment and temperament were collected from direct observations as well as from standardized questionnaires. The results show no significant differences in developmental testing outcomes between children of marijuana-using and non-using mothers except at 30 days of age when the babies of users had more favourable scores on two clusters of the Brazelton Scales: autonomic stability and reflexes. The developmental scores at ages 4 and 5 years were significantly correlated to certain aspects of the home environment and to regularity of basic school (preschool) attendance.

Five-year follow-up of rural Jamaican children whose mothers used marijuana during pregnancy

This research provides data on the development of 59 Jamaican children, from birth to age 5 years, whose mothers used marijuana during pregnancy. Approximately one-half of the sample used marijuana during pregnancy and were matched with non-users according to age, parity, and socioeconomic status. Testing of the children was done at 1, 3, and 30 days of age with the Brazelton Neonatal Behavioral Assessment Scales and at ages 3 and 5 years with the McCarthy Scales of Children's Abilities. Data about the child's home environment and temperament were collected from direct observations as well as from standardized questionnaires. The results show no significant differences in developmental testing outcomes between children of marijuana-using and non-using mothers except at 30 days of age when the babies of users had more favourable scores on two clusters of the Brazelton Scales: autonomic stability and reflexes. The developmental scores at ages 4 and 5 were significantly correlated to certain aspects of the home environment and to regularity of basic school (preschool) attendance.

Newly incriminated anopheline vectors of human malaria parasites in Junin Department, Peru.

Sporozoite data from salivary gland dissections are presented that clearly incriminate Anopheles trinkae, An. pseudopunctipennis, An. sp. near fluminensis, An. oswaldoi, An. nuneztovari and An. rangeli as vectors of malaria parasites in the Rio Ene Valley, a hyperendemic malarious area in Junin Department, eastern Peru. Anopheles trinkae is considered the most important vector based on dissections, abundance and man-vector contact. Other notes are presented on the relative abundance, bionomics and previous records of these species in Peru and in the study sites.

Malassezia furfur skin colonization of infants hospitalized in intensive care units.

We studied the prevalence of Malassezia furfur skin colonization of infants hospitalized in our neonatal and infant cardiac and surgical intensive care units by culturing at monthly intervals. Of 361 infants studied over 1 year, 133 (36.8%) had at least one positive culture for M. furfur. Colonized infants, compared with noncolonized infants, had younger mean gestational age (32.4 vs 35.2 weeks, P less than 0.01), lower mean birth weight (1.76 vs 2.31 kg, P less than 0.01), a longer stay in hospital (Wilcoxon P less than 0.01), and more mean days use of an incubator (12.7 vs 7.6 days, P less than 0.01), lamb wool (12.9 vs 8.2 days, P less than 0.01), paper tape (10.8 vs 8.2 days, P less than 0.01), and Op-Site tape (14.1 vs 10.1 days, P less than 0.01). These data suggest that hospitalization in an infant intensive care unit often leads to M. furfur colonization. Although frequent adult handling may be a source, other aspects of intensive care will require careful scrutiny to define more completely the risk factors leading to M. furfur colonization of ill infants.

Prevalence of chloroquine-resistant falciparum malaria in the Brazilian Amazon.

The prevalence of chloroquine-resistant falciparum malaria was determined for humans living at 28 different sites in the Brazilian Amazon. Blood samples obtained from each patient were defibrinated, placed in vials containing 0.5% glucose and or chloroquine and incubated for 24 hours at 39-40 degrees C without agitation. In vitro sensitivity of the parasite to four different concentrations of chloroquine was determined for each sample. After 24 hours of incubation, trophozoites of Plasmodium falciparum developed to schizonts in all control cultures (no chloroquine) as well as in 80.6, 48.4, 11.8 and 7.5% of the cultures containing 0.5, 1.0, 2.0, and 3.0 nmol chloroquine/ml blood, respectively. Chloroquine-resistant P. falciparum was found in blood samples from all 28 locations, indicating that such resistance is widely spread in the Brazilian Amazon.

Drug-resistant falciparum malaria among the Mayongong Indians in the Brazilian Amazon.

In April of 1977 an outbreak of falciparum malaria occurred among the Mayongong Indians, located at Uauaris in the Territory of Roraima, Brazil. Blood specimens from 157 Indians were examined for Plasmodium; 62 were found to be infected. In three cases the infection was not cured with chloroquine but responded favorably to the drug combination of sulfadoxine and pyrimethamine (Fansidar).

Galactorrhea in a 12-year-old boy with a chromophobe adenoma.

A 12-year-old with galactorrhea is presented. He was in early puberty, had gynecomastia, and was markedly obese. Roentgenograms of the skull showed an asymmetrically enlarged sella trucica, but pneumoencephalography did not indicate suprasellar extension of the pituitary tumor. Preoperative studies of anterior pituitary function were normal except for persistent hyperprolactinemia. By transsphenoidal approach, a microadenoma of the pituitary was removed. Lactation ceased within a week, and four months postoperatively the patient had normal anterior pituitary function studies. A review of the literature indicates that galactorrhea in males is very rare. The most frequently documented cause, excluding drug ingestion, is a pituitary tumor.

Hereditary nephritis (with unusual renal histology): report of a first case from the West Indies.

A 21-year-old Grenadian girl undergoing investigation in Trinidad for anaemia was diagnosed as a case of hereditary nephritis. She had the clinical features of a nephropathy, nerve deafness and an ocular defect. Renal histology was exceptional in that in addition to the typical findings of a hereditary nephritis, cystic areas generally associated with medullary cystic disease were noted. Several members of the patient's maternal family were afflicted with either deafness visual distrubances or renal disease.

Post-streptococcal glomerulonephritis in North Trinidad.

A retrospective study of the admissions of cases of acute post streptococcal glomerulonephritis to the main hospital serving North Trinidad over a five-year period was made. Follow-up examination suggests that there is an initially good prognosis for those afflicted in early childhood whilst adolescents manifest effects of permanent renal damage at a much earlier stage after the acute attack.