PubMed Health⌕ Search

Biomedical subjects

D L Heymann

Publications and source records attributed to D L Heymann.

At least 55 records · Page 3Linked to original sources
PubMed1992

HIV infection and breast-feeding: policy implications through a decision analysis model.

OBJECTIVES: (1) To develop a comprehensive decision analysis model to compare mortality associated with HIV transmission from breast-feeding with the mortality from not breast-feeding in different populations and (2) to perform sensitivity analyses to illustrate critical boundaries for guiding research and policy. METHODS: Using a decision tree, mortality rates were estimated for all children, children born to mothers infected during pregnancy, and children born to mothers who were uninfected at delivery. Given various assumptions about child mortality rates, relative risks of mortality among children who are not breast-fed compared with those who are (R), rates of HIV transmission from breast-feeding, HIV prevalence, and HIV incidence, scenarios were created and sensitivity analysis used to delineate critical boundaries. RESULTS: Our model shows that only in situations where R is approximately < or = 1.5 and HIV incidence/prevalence is high (prevalence > 10%, incidence > 5%) would universal breast-feeding result in equal or higher mortality compared with non-breast-feeding. Among populations in many developing countries, where there is a high relative risk of mortality if breast-feeding is not practiced, if R > 3, overall mortality is almost always lower among children who are breast-fed, even by HIV-infected mothers. In situations where maternal HIV status is known, the decision whether to breast-feed is largely dependent on the magnitude of additional mortality risk if the child is not breast-fed. The model illustrates the importance of distinguishing between population and individual recommendations. CONCLUSIONS: Based on available data, the model supports current World Health Organization and Centers for Disease Control recommendations on HIV infection and breast-feeding. Given the importance of breast-feeding and the global impact of HIV infection, more research is needed, especially to clarify the range of HIV transmission rates from breast-feeding and to expand specific assessments of relative risks for different areas of the world.

Breast Feeding↗
PubMed1991

Acquired immunodeficiency syndrome in Romania.

After the initial description of acquired immunodeficiency syndrome (AIDS) in Romania in late 1989, national AIDS case surveillance was established with a modified version of the World Health Organisation (WHO) clinical case definition. This modified case definition requires that AIDS cases have both clinical and serological evidence of human immunodeficiency virus (HIV) infection. Before December, 1989, Romania had reported 13 AIDS cases to WHO. By Dec 31, 1990, 1168 AIDS cases were reported to Romania's Ministry of Health, of which 1094 (93.7%) occurred in children less than 13 years of age at diagnosis. Of these, 1086 (99.3%) were in infants and children less than 4 years of age, and 683 (62.4%) in abandoned children living in public institutions at the time of diagnosis. By Dec 31, 1990, 493 (45.1%) mothers of children with AIDS had been located and tested, and 37 (7.5%) were positive for HIV; 423 (38.7%) cases were in children who had received transfusions of unscreened blood, and 6 (0.5%) were in children with clotting disorders. HIV transmission through the improper use of needles and syringes is strongly suspected in most of the remaining 628 (57.4%) children with AIDS, most of whom had received multiple therapeutic injections. This outbreak demonstrates the serious potential for HIV transmission in medical facilities that intensively and improperly use parenteral therapy and have poor sterilisation technique.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Transmission of HIV, hepatitis B virus, and other bloodborne pathogens in health care settings: a review of risk factors and guidelines for prevention. World Health Organization.

Recent reports of the transmission of human immunodeficiency virus (HIV) in health care settings have caused considerable public health concern. HIV as well as hepatitis B virus (HBV) and other bloodborne pathogens do constitute infectious hazards in certain settings. Transmission has been reported from patient to patient, patient to health care workers, and rarely, from health care worker to patient. Although the risk of bloodborne pathogen transmission is largely preventable, it may occur due to the use of infected blood for transfusion, the use of improperly sterilized medical or dental equipment, and accidental punctures with contaminated instruments. The risk of transmission of bloodborne pathogens is dependent on a number of factors and appears to be greater for HBV than for HIV. General guidelines for the prevention of transmission in health care settings are given, including the concept of "universal precautions", the need for adequate supplies of sterile equipment, the reduction of unnecessary injections and transfusions, and the appropriate use of hepatitis B vaccine. In addition, areas for research are highlighted that could improve understanding of transmission risks in different health situations and provide the information necessary to develop more effective measures to protect both care providers and patients.

Cross Infection↗
PubMed1990

In vivo efficacy of quinine treatment for Plasmodium falciparum malaria in Malawian children.

Twenty-five Malwaian children with Plasmodium falciparum infection were studied for response to quinine in an eight-hourly dosage of 10 mg salt kg-1 body weight. The mean parasite clearance time, defined as the time after initiation of treatment when the first of two consecutive 12-hourly smears was negative for P. falciparum parasites, was 67 hours. The mean fever clearance time, defined as the time after initiation of treatment when the axillary temperature first fell below 37.5 degrees C and remained below this level for 48 hours, was 36 hours. Twenty-four hours after the first dose of quinine, the geometric mean parasite density among the children studied had decreased by 84%, from 41 357-6586 parasites mm-3, and all children cleared their parasitaemia within 108 hours. Results of this study confirm that quinine remains effective in rapidly controlling P. falciparum parasitaemias in Malawi, where resistance to the 4-aminoquinolines is highly prevalent.

Administration, Oral↗
PubMed1990

Mefloquine therapy for Plasmodium falciparum malaria in children under 5 years of age in Malawi: in vivo/in vitro efficacy and correlation of drug concentration with parasitological outcome.

The in vivo and in vitro response of Plasmodium falciparum to a single oral dose of mefloquine (25 mg/kg body weight (M25) or 15 mg/kg (M15] was studied in children under 5 years of age in Malawi. Of the children who received mefloquine, 35% vomited at least once, and 10% did not tolerate the drug because of vomiting. The therapy failure rates for the M25 group on day 7, 14, and 28 were 15%, 18%, and 42%, respectively, and these did not differ significantly from those for the M15 group (4%, 18%, and 59%). In contrast, 34 in vitro microtests (17 per group) showed schizont inhibition at less than or equal to 32 pmol mefloquine per test well. On day 7, the concentration of mefloquine in samples of blood was significantly lower in both the M25 and M15 groups for children who were parasitaemic on day 7 than in samples from those who were aparasitaemic. A positive blood smear on day 7 was strongly associated with a mefloquine concentration of less than 500 ng/ml blood on day 2 or day 7 (P less than 0.0003). Vomiting was associated with a low mefloquine concentration on day 2 but not day 7. These results suggest that mefloquine is effective against P. falciparum in Malawi but that for young children the therapy appears to be complicated by frequent vomiting.

Animals↗
PubMed1990

Oral rehydration therapy in Malawi: impact on the severity of disease and on hospital admissions, treatment practices, and recurrent costs.

In the first 2 years following refresher training of paediatric staff in oral rehydration therapy (ORT) and the establishment of an oral rehydration unit at the Kamuzu Central Hospital, Lilongwe, Malawi, there was a 50% decrease in the number of children admitted to the paediatric ward with the diagnosis of diarrhoeal diseases, a 56% decrease in the use of intravenous fluid to rehydrate such children, a threefold increase in the use of oral rehydration salts (ORS) exclusively to rehydrate children with mild or moderate dehydration, and a 39% decrease in the number of paediatric deaths associated with diarrhoeal diseases. Over the same period, there was a 32% decrease in recurrent hospital costs attributable to paediatric diarrhoeal diseases. As use of ORT continues to increase in Malawi, where diarrhoeal diseases account for 9% of paediatric hospital admissions, there should be considerable decreases in mortality from such diseases and concomitant increases in cost savings attributable to them.

Child, Preschool↗
PubMed1988

Efficacy of chemoprophylaxis in preventing Plasmodium falciparum parasitaemia and placental infection in pregnant women in Malawi.

73 pregnant women in Malawi were given weekly antimalarial chemoprophylaxis under observation and were monitored for Plasmodium falciparum parasitaemia and placental infection. 3 of 19 women (16%) who were parasitaemic at the time they began chemoprophylaxis were infected with chloroquine-resistant P. falciparum. After clearance of initial infections, 25% of the 73 women became parasitaemic while taking prophylaxis and 56% had evidence of active or past placental infection at the time of delivery. None of the women who were parasitaemic at the time of enrollment, and only 11% of those who had breakthrough parasitaemias while taking prophylaxis, had a history of fever and signs or symptoms that they recognized as malaria. Although the density of P. falciparum infection and rates of placental infection appeared to be lower among women taking regular chloroquine prophylaxis, this drug did not prevent P. falciparum infection among pregnant women.

Amodiaquine↗
PubMed1987

Comparative efficacy of alternative primary therapies for Plasmodium falciparum infections in Malawi.

In Malawi, where high levels of chloroquine resistance were shown using a modified 7-day in vivo test, amodiaquine and pyrimethamine-sulfadoxine were evaluated as alternative initial therapies for Plasmodium falciparum infections in children under 5 years old. Therapy success rates, judged by parasite clearance by day 7 after initiation of therapy, were significantly greater among 39 children treated with amodiaquine at 10 mg/kg (90%), 37 receiving amodiaquine at 25 mg/kg (97%), and 34 receiving pyrimethamine-sulfadoxine (100%) at a dose of 25 mg sulfadoxine/kg, than among those treated with chloroquine at a dose of 25 mg/kg (59%) (P = 0.01). Extension of the follow-up period of those receiving amodiaquine (25 mg/kg) and pyrimethamine-sulfadoxine to 21 d revealed a progressively increasing rate of parasite recrudescence in the amodiaquine group (34%), but no recrudescence in the pyrimethamine-sulfadoxine group. These results suggest that, in Malawi, amodiaquine and pyrimethamine-sulfadoxine are superior to chloroquine in producing prompt clearance of P. falciparum parasites among young children, and that pyrimethamine-sulfadoxine alone is superior to the 4-aminoquinolines in sustaining P. falciparum clearance.

Amodiaquine↗
PubMed1987

Oral poliovirus vaccine in tropical Africa: greater impact on incidence of paralytic disease than expected from coverage surveys and seroconversion rates.

During the first 5 years of a poliomyelitis control programme in Yaounde, Cameroon, a maximum of 35% of children aged 12-23 months were estimated to have received three doses of trivalent oral vaccine. Despite this low immunization coverage and low seroconversion rates, which were determined concurrently, the estimated incidence of paralytic poliomyelitis decreased by 85%.A detailed study of immunized children and of children living in the same households suggests that community spread of the vaccine virus and cross-immunity may have partly been responsible for the dramatic decrease in the incidence of paralytic disease, and that competing non-polio enterovirus infection was not a cause for the low seroconversion rates. These results suggest that immunization coverage and seroconversion rates alone are not sufficient criteria for determining the effectiveness of control programmes that use oral poliovirus vaccine in tropical Africa; surveillance of the incidence of paralytic disease must also be carried out.

Antibody Formation↗
PubMed1986

In vivo efficacy of chloroquine treatment for Plasmodium falciparum in Malawian children under five years of age.

In 1984 the government of Malawi instituted a program to reduce malaria mortality and morbidity in children less than 5 years of age as a part of the Combatting Childhood Communicable Diseases (CCCD) program. To define the appropriate malaria therapy regimen, investigators used a quality assurance design in a simplified 7-day in vivo drug response study with follow-up observations on day 2 (D2), D3, and D7 after the initial day of the study (D0). The efficacy of oral chloroquine was assessed in 224 children who were enrolled at 6 sites, 2 in each of the 3 administrative regions of Malawi. Parasitological failure, defined as failure of parasitemia to decrease by 75% of the value by D3 or presence of any detectable parasitemia on D7, ranged from 41%-65% following administration of chloroquine 25 mg (base)/kg. However, only 8% of children who were parasitemic on D7 were febrile or judged to be ill. Considering these therapeutic results and the higher cost and limited availability of alternative therapies, chloroquine 25 mg/kg therapy was adopted as the primary therapy for malaria.

Administration, Oral↗
PubMed1983

Estimation of incidence of poliomyelitis by three survey methods in different regions of the United Republic of Cameroon.

Surveys were conducted in one urban and two rural regions of the United Republic of Cameroon to estimate the annual incidence of paralytic poliomyelitis. Three different survey methods were used: a review of hospital and clinic registers, a school survey, and a house-to-house survey. The house-to-house survey identified the highest number of lame children and gave estimates of incidence of between 18.8 and 32.6 per 100 000 population in the three regions. The estimates of incidence obtained by the two other survey methods in the urban region did not differ significantly from that obtained by house-to-house survey but, in the rural regions, were significantly lower. It is concluded that house-to-house surveys are a sensitive method of identifying lame children in both urban and rural regions. School surveys and review of hospital and clinic registers, while equally sensitive in urban regions, are less sensitive in rural regions and may significantly underestimate the annual incidence of paralytic poliomyelitis. These limitations should be borne in mind when using the survey methods.

Cameroon↗
PubMed1982

Further field testing of the more heat-stable measles vaccines in Cameroon.

Two of the more heat-stable measles vaccines were field tested in Cameroon. Both maintained the minimum required infectivity titre and the ability to induce seroconversion after storage unreconstituted at 37 degrees C for 14 days. One of the vaccines, studied after reconstitution, maintained its ability to induce seroconversion after reconstitution and storage at 25 degrees C for 48 hours and at 37 degrees C for at least four hours. The increased heat stability of the studied vaccines will not eliminate the need for a well-monitored system of vaccine conservation and distribution but will ease the rigid cold-storage requirements of conventional measles vaccines.

Antibodies, Viral↗
PubMed1981

Prophylaxis of varicella in high-risk children: dose-response effect of zoster immune globulin.

Immunodeficient patients who were presumed to be susceptible received zoster immune globulin prophylaxis after exposure to varicella. The highest clinical attack rate (35.9%) was seen in household contacts; the lowest attack rate (0%) was observed in children exposed at school. Among household contacts, 48 of 100 patients who received high titer ZIG (reciprocal complement fixation titer greater than or equal to 2,560) developed fourfold rises in serum CF antibody between pre- and 48-hour post-treatment specimens, compared to only one of 34 patients treated with lower titer ZIG lots (P less than 0.001). Patients who developed fourfold antibody rises were significantly less likely to contract clinical varicella (P less than 0.01). Patients who received high titer ZIG also had significantly lower risks of death (P = 0.025) and complications (P = 0.006). Among ZIG-treated patients who contracted clinical varicella, 80% developed mild disease (less than 100 pox), and the median incubation period was prolonged. Immunodeficient children exposed to varicella benefit from ZIG prophylaxis and higher titer ZIG is of greatest benefit.

Adolescent↗
PubMed1981

Preparation of polyvalent viral immunofluorescent intracellular antigens and use in human serosurveys.

A method is described for preparation of polyvalent antigens for use in rapid screening for immunofluorescent antibodies to Lassa, Marburg, and Ebola viruses. The technique uses mixtures of specifically infected Vero cells placed on Teflon-templated microscopy slides. It was found to be as sensitive as the use of monovalent antigens for detection and quantitation of antibodies to these highly hazardous human pathogens.

Animals↗
PubMed1980

Ebola hemorrhagic fever: Tandala, Zaire, 1977-1978.

Ebola virus was recovered from a nine-year-old girl who died of acute hemorrhagic fever in June 1977 at Tandala Hospital in northwestern Zaire, in the first reported recognized case of this disease since the discovery epidemics of 1976 in Zaire and Sudan. Investigations undertaken in the Tandala region revealed that two previous clinical infections with Ebola virus had occurred in 1972 and that about 7% of the residents had immunofluorescent antibodies to the virus. Females younger than 30 years of age had a higher prevalence of antibodies than males of comparable age, but above the age of 30 years there was no sex difference. No other clues to the still-mysterious natural reservoir of Ebola virus were uncovered.

Adolescent↗