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Biomedical subjects

H C Spencer

Publications and source records attributed to H C Spencer.

At least 19 recordsLinked to original sources
PubMed1995

Perspectives of public health and prevention.

The average life expectancy at birth of Americans has increased 30 years since the turn of the century and is mostly attributable to public health measures. Although death rates for cardiovascular diseases have declined in the past two decades, cardiovascular diseases still cause more deaths in the United States than all other causes combined. The major etiologies of heart disease, atherosclerosis and hypertension, are associated with modifiable risk factors--high blood cholesterol, high blood pressure, cigarette smoking, diet, and inactivity. Social status and access to medical care are also important contributors. Consequently, the greatest potential for reducing heart disease mortality and morbidity rests with prevention and public health practice. Recent directions in health-care reform emphasize fiscal management, medical care, and clinical medicine, and not general health. This emphasis exacerbates policy and financing imbalances between preventive and curative medicine. Consequently, the concept of a health system needs to be designed more rationally to allocate resources that include prevention and health promotion. The Bogalusa Heart Study provides understanding of the early origin of cardiovascular problems and the environmental and lifestyle factors that contribute to development of adult heart disease. To apply this information, public health models of intervention, like the school Health Ahead/Heart Smart program, are needed to address heart disease in the population. Changes in the true determinants of poor health, such as environmental factors and unhealthy behaviors, are the directions for prevention and future improvement in quality of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Intestinal parasitism in the United States: update on a continuing problem.

To document patterns of intestinal parasitism in the United States, we analyzed results of 216,275 stool specimens examined by the state diagnostic laboratories in 1987; parasites were found in 20.0%. Percentages were highest for protozoans: Giardia lamblia (7.2%), Entamoeba coli and Endolimax nana (4.2% each), Blastocystis hominis (2.6%), and Entamoeba histolytica (0.9%). The most commonly identified helminths were nematodes: hookworm (1.5%), Trichuris trichiura (1.2%), and Ascaris lumbricoides (0.8%). Identifications of G. lamblia increased broadly from the 4.0% average found in 1979, with 40 states reporting increases and seven reporting decreases. Seasonally, Giardia identifications increased in the summer and fall, especially in the Midwest. Nine states reported hookworms in more than 2% of specimens; none were states with indigenous transmission. We analyzed similar, but abbreviated, data for 1991; parasites were found in 19.7% of the 178,786 specimens and Giardia was found in 5.6%. States reporting percentages of Giardia identification in the highest quartile for both 1987 and 1991 were located in the Midwest or in the Northwest. Cryptosporidium was identified in both the 1987 and 1991 surveys; it had not been identified in a previous survey. For each year, Cryptosporidium was reported from 25 states across the country (for both years in 17 states). We conclude that intestinal parasitism should not be overlooked as a cause of gastrointestinal illness in the United States and that the prevalence of Giardia may be increasing.

Animals↗
PubMed1993

Comparative efficacy of clearing-dose and single high-dose ivermectin and diethylcarbamazine against Wuchereria bancrofti microfilaremia.

To compare the efficacy and tolerability of various combinations of low- and high-dose ivermectin and diethylcarbamazine (DEC), 59 persons with Wuchereria bancrofti microfilaremia were enrolled in a double-blinded six-arm clinical trial in Leogane, Haiti. On day 1, study participants were treated with low clearing doses of ivermectin, DEC, or placebo; on day 5 they received 200-400 micrograms/kg of ivermectin or 6 mg/kg of DEC. Adverse reactions, which were generally mild, occurred more frequently with ivermectin than with DEC. One year after treatment, the geometric mean microfilarial density returned to 0.9% of pretreatment levels for persons who received a total of 420 micrograms/kg of ivermectin. This rate was significantly lower than 5.6% for persons who were treated with 220 micrograms/kg of ivermectin (P = 0.02) and 9.3% for those receiving 6 or 7 mg/kg of DEC (P = 0.006). Persons treated with a clearing dose of ivermectin followed by 6 mg/kg of DEC also had low microfilarial densities (1.7% of pretreatment levels), suggesting an additive or synergistic effect of the two drugs. The addition of a clearing dose neither reduced the severity of adverse reactions nor improved the efficacy of high-dose ivermectin. Community-based intervention trials are now warranted to determine the feasibility and effectiveness of mass chemotherapy with single high-dose ivermectin for the prevention and control of lymphatic filariasis.

Adolescent↗
PubMed1993

Recent trends in the prevalence and distribution of schistosomiasis in the Nile delta region.

In 1983, a survey of 71 villages in the Nile delta demonstrated that the overall prevalence of Schistosoma mansoni and S. haematobium infections was 39% and 5%, respectively. Recent increased availability of praziquantel, combined with Egyptian Ministry of Health-sponsored media efforts to educate the public about schistosomiasis, prompted us to determine the current status of S. mansoni and S. haematobium infections in the delta and evaluate any changes that may have occurred since the previous survey. The same villages that participated in the 1983 survey were resampled in 1990. Stool and urine samples were requested from all occupants over the age of two years in a 5% sample of houses within each village. Stool (Kato) thick smears and urine sediments were read qualitatively at the rural health station. Field-prepared Kato smears and a 20% sample of urine specimens were forwarded to the Ministry of Health Laboratory, where quantitative readings were also performed. Analysis of samples obtained from 17,310 persons revealed that S. mansoni prevalence had decreased to 23% and that S. haematobium prevalence had decreased to 3% (P < 0.001). The highest levels of schistosome infection were found in governates located in the eastern section of the delta. The observed changes in the prevalence of S. mansoni and S. haematobium suggest that control measures are having a favorable impact on schistosomiasis transmission in this region.

Adolescent↗
PubMed1992

Infectious diseases and injuries in child day care. Opportunities for healthier children.

OBJECTIVE: To provide pertinent background information on infectious diseases and injury in child day care and outline measures to address these health care needs. DESIGN: We reviewed published English-language literature identified through a MEDLINE bibliographic search, major literature summaries, and bibliographies from identified articles. SETTING: Child day-care settings reviewed included family child care homes, centers, special facilities for ill children, and facilities for children with special needs. PATIENTS OR OTHER PARTICIPANTS: Primarily children in a variety of day-care settings, often compared with children cared for at home. MAIN OUTCOMES: The occurrence of outbreaks and illness related to infectious disease and injury. RESULTS: Compared with preschool-aged children reared at home, among children in day care the risk of some infectious diseases was two to four times greater. Rates of both intentional and unintentional injuries in day-care settings were somewhat lower than those for children cared for at home. CONCLUSIONS: Because preschool-aged children spend increasing time in structured day-care settings, the risk for some infectious diseases has increased. At the same time, child day-care settings present opportunities for ensuring healthier children through enhanced development, safer environments, better nutrition, increased vaccination coverage, and health promotion.

Child Abuse↗
PubMed1992

Alterations in filarial antigen-specific immunologic reactivity following treatment with ivermectin and diethylcarbamazine.

The presence of circulating microfilariae has been associated with alterations in B and T cell functions. In this study, we compared the influence of diethylcarbamazine (DEC) and ivermectin on filarial antigen-specific immune responses in a Haitian population. Both drugs were effective at reducing microfilaremia levels to less than 10% of pretreatment levels for up to one year. This reduction in microfilaremia was associated with two phases of altered cellular responsiveness monitored with in vitro assays. Five days post-treatment, cellular proliferation in response to both filarial and nonfilarial antigens was significantly increased, as was the background response in the absence of any antigen. At both nine months and one year post-treatment, the filarial antigen-specific reactivity of both DEC- and ivermectin-treated patients was significantly increased over baseline levels. No differences were observed between the two treatment groups in terms of humoral or cellular reactivity to filarial antigens, despite evidence suggesting a role for DEC in adult worm killing. These results provide additional evidence that microfilariae modulate antifilarial immune reactivity.

Animals↗
PubMed1991

Giardia lamblia and Cryptosporidium infections in child day-care centers in Fulton County, Georgia.

Risk factors for the introduction, spread and persistence of Cryptosporidium and Giardia lamblia infections in child day-care centers are not well understood. In 1989 and 1990 stool specimens were obtained from 292 diapered children attending 17 randomly selected day-care centers in Fulton County, GA; 8 (2.7%) children in 2 centers were infected with Cryptosporidium and 21 (7.2%) children in 7 centers were infected with Giardia. In 1986 the prevalence of Cryptosporidium and Giardia in these same centers had been 0.4 and 11.0%, respectively; the prevalence of Cryptosporidium, but not Giardia, increased significantly (P = 0.04) between 1986 and 1989 to 1990. Risk factors for Giardia infection included day-care attendance for greater than 3 months, the presence of toddlers in the classroom and the presence of other children in the household. Day-care centers with a Giardia-positive child in 1986 were not more likely to have an infected child in 1989 to 1990. Cryptosporidium, like Giardia, may be endemic in day-care centers in Fulton County.

Child Day Care Centers↗
PubMed1991

Evaluation of a commercially available enzyme-linked immunosorbent assay for Giardia lamblia antigen in stool.

The lack of a quick, simple, and inexpensive diagnostic test has limited the ability of public health officials to rapidly assess and control outbreaks of Giardia lamblia in child day-care centers. We evaluated the performance of a commercially available enzyme-linked immunosorbent assay (ELISA) for the detection of a G. lamblia-associated antigen in stool. Stool specimens were collected from the diapers of 426 children attending 20 day-care centers, fixed in 10% Formalin and polyvinyl alcohol, and examined by microscopy by Formalin concentration and trichrome staining techniques. Specimens were also tested visually and spectrophotometrically by ELISA. Of 99 tests positive by microscopy, 93 were visually positive by ELISA (sensitivity, 93.9%). Of 534 tests negative for G. lamblia by microscopy, 32 (6.0%) were ELISA positive. However, on the basis of examination of multiple specimens from the same child, none of these could be considered false-positive ELISAs; the specificity of the ELISA was therefore 100%. The sensitivity of both microscopy and ELISA improved as the number of specimens per child increased. An optical density value of greater than 0.040 was 98.0% sensitive and 100% specific for G. lamblia. This ELISA, which appeared to be more sensitive for G. lamblia than did microscopic examination of stool, should be useful as an epidemiologic tool, particularly in day-care settings, and may also have a role in confirming clinical diagnoses of giardiasis.

Animals↗
PubMed1991

Comparison of high dose ivermectin and diethylcarbamazine for activity against bancroftian filariasis in Haiti.

This three-phase study was designed to compare high dose ivermectin with a standard diethylcarbamazine (DEC) regimen for patient tolerability, potential to kill adult filaria, and duration of microfilarial suppression in 30 Haitian subjects with Wuchereria bancrofti microfilaremia. All were first given a 1-mg oral dose of ivermectin (phase 1) to reduce microfilaria densities. Participants were randomized into three groups: Group 1 received DEC (6mg/kg per day for 12 days), Group 2 received 200 mcg/kg of ivermectin, and Group 3 received 400 mcg/kg of ivermectin (200 mcg/kg per day for 2 days). All drug regimens were well tolerated with few adverse reactions. Most reactions occurred during phase I and consisted primarily of headache, fever, and myalgia. At the end of phase 1, 27 of 30 (90%) patients were microfilaria negative. During phase 2, four of the six men receiving DEC developed scrotal reactions suggesting killing adult worms; no such reactions were noted in 10 men receiving ivermectin (p less than 0.05). At one-year follow up (phase 3), all treatment groups had less than 10% return to pretreatment microfilaria levels. The mean percent of baseline microfilaria counts were for Group 1, 0.9% (range 0-5%); Group 2, 8.2% (range 0-31%); and Group 3, 3.8% (range 0-25%). Seven individuals in Group 1 were microfilaria-negative, while only one and three individuals were microfilaria-negative in Groups 2 and 3, respectively. These results suggest that DEC causes more damage to the adult worms and greater reduction in microfilaria densities than ivermectin, but that high doses of ivermectin may suppress microfilaremia in lymphatic filariasis for periods much longer than previously reported.

Adolescent↗
PubMed1990

Evaluation of UNICEF/Arab Republic of Egypt/WHO schistosomiasis Control Project in Beheira Governorate.

We evaluated the UNICEF/Government of Egypt/WHO Schistosomiasis Control project in 2 districts of Beheira Governorate of the Nile Delta during 3 weeks in February 1988. The project, begun in 1983, was focused on reducing prevalence, intensity, and morbidity due to schistosomiasis by providing diagnosis and treatment with praziquantel to schoolchildren. Schools were visited twice. Following the completion of the school surveys, the program was extended into the community. Chemotherapy was delivered by mobile and static teams. The evaluation indicated that, with respect to accuracy of diagnosis, record-keeping, and coverage of targeted populations, project tasks were performed exceedingly well by highly motivated, well-supervised mobile teams. Static teams in rural health centers were less successful in providing diagnosis and chemotherapy to village populations. We resurveyed 6 randomly selected schools to assess the impact of chemotherapy. Overall, the prevalence of Schistosoma mansoni infection was reduced from 60.3% to 24.8% between the first and second surveys (approximately 1 year apart) and was still lower (41.1%) than initial levels up to 3 years after the last treatment with praziquantel. The percentages of those with greater than or equal to 34 S. mansoni eggs/slide using the Kato-Katz technique showed a marked and prolonged decrease (17.1% to 0.3% to 2.2%). The prevalence of S. haematobium infection dropped from 37.6% to 5.5% and was still 9.9% at the time of the evaluation. The percentages of those with greater than or equal to 50 S. haematobium eggs/10 ml urine dropped less dramatically (17% to 4.4% to 11.9%). Mobile teams conducting vigorous chemotherapy programs targeted at schoolchildren can have long-lasting benefits in terms of prevalence and intensity.

Child↗
PubMed1987

The Saradidi, Kenya, rural health development programme.

A primary health care community development programme was initiated in 1979 by people living in Saradidi, Kenya. The community was involved in planning, organization, setting of priorities and objectives, implementation, evaluation and benefits. This paper describes the developmental process that occurred including how the programme began, how it was organized and what it attempted to accomplish.

Community Health Services↗
PubMed1987

Community-based malaria control in Saradidi, Kenya: description of the programme and impact on parasitaemia rates and antimalarial antibodies.

A community-based malaria control programme initiated in Saradidi, Kenya in 1982 is described. Antimalarial treatment provided by volunteer community health workers was made available in each village. Malaria was holoendemic. Parasitaemia rates by age were high and did not change after the control programme began. Plasmodium falciparum was the most common species and was present alone or mixed in 98.2% of 8105 infections. Virtually all (98.5%) of 2040 blood samples collected in May 1981 were positive (reciprocal titre greater than or equal to 80) to P. falciparum by the indirect fluorescent antibody (IFA) test. Seropositivity rates to P. falciparum in the IFA test or the enzyme-linked immunosorbent assay (ELISA) were high in all age groups and did not change significantly in longitudinal surveys or in a cohort of children zero to nine years old followed at intervals. While the malaria control programme was successful in bringing treatment to each village, malaria prevalence was not reduced. Parasitologic and serologic studies alone were not adequate to describe the impact of the community-based malaria control programme in Saradidi. Morbidity and mortality rates caused by malaria can decline, significantly improving the health of the population, in the absence of any decrease in parasitaemia rates.

Animals↗
PubMed1987

The Saradidi, Kenya, rural health development programme: retrospective demographic analysis.

A census was done in Saradidi, Kenya from 1980 to 1982 as part of a community-based health development programme. The population was 42,755 (excluding 39 persons of unknown age or sex); 17.1% were less than five years old, 46.9% were below age 15, 4.7% were age 65 years or older and 19.7% were women in the reproductive years (age 15 to 44 years). The sex ratio was 86 males per 100 females due principally to migration of adult males for work. The mean number of persons per household was 4.0 and the mean village population was 764. The singulate mean age of marriage for men was 27.0 years and for women 19.9 years; 0.8% of adult men had never married. Only 0.1% of women by age 50 had never been married. Men were significantly more likely than women to be married to more than one spouse, divorce and separation was higher among men, and by age 50 about one-third of women were widows. Men had more years of formal education than women and young people of both sexes more than older people; 73.1% of men and 96.1% of women 60 years and more had never attended school. Infant mortality rates estimated indirectly ranged between 139 and 155 by area. A strong association was found between increasing education of the mother and decreased reported mortality of children. The total fertility of 6.2 was high but lower than the national average possibly because of the high rates of polygamy and primary infertility and the long periods of amenorrhoea and breast feeding which occurred after delivery. This area continues to have one of the highest levels of infant and child mortality in Kenya as well as relatively high fertility and a population with a very young age structure. This implies a continued very rapid rate of population growth which will make more difficult in the future the problems of delivering effective health services and overcoming poverty. A vigorous programme directed toward improving health is indicated which must include family planning.

Community Health Services↗
PubMed1987

Impact on mortality and fertility of a community-based malaria control programme in Saradidi, Kenya.

Mortality and fertility rates were measured from 1981 to 1983 by prospective registration of vital events as part of a community-based malaria control and health development programme in Saradidi, Kenya. There was no obvious effect of providing chloroquine phosphate for treatment of malaria in each village on mortality or fertility rates. Crude death rates were 13.1 in the year before intervention (1 May 1981 to 30 April 1982) and 12.3 after intervention (1 September 1982 to 31 August 1983). Neonatal mortality increased from 36.8 per 1000 live births pre-intervention to 49.1 during intervention. There was a slight decline in post-neonatal (one to 12 months) mortality (72.8 to 67.0) and a significant drop in early childhood mortality (25.2 to 18.2). The change in mortality rates in these two age groups were fully explained by a high rate of measles mortality in the pre-intervention period. Measles accounted for 35.7% of 284 reported deaths in infants one to 12 months of age and for 40.9% of 230 deaths in children one to four years old. There was little change in reported malaria-specific mortality rates in infants and young children most likely because of a high level of chloroquine use for treatment of presumptive illness. Perinatal mortality by area ranged between 60.4 and 81.3 pre-intervention to 79.5 to 97.2 after the control programme was instituted. Crude birth rates by area remained stable at about 40 and general fertility rates were about 200. Both pre-intervention and during intervention infants were significantly more likely to have died without medical consultation than children one to four years. However, 79.2% of 284 infants and 90.7% of 193 children died in spite of having consulted a health worker prior to death. The data suggest that a measles vaccine programme would significantly reduce mortality rates in infants and young children. The fact that the majority of infants and young children died in spite of receiving medical attention indicates both the inadequacy of curative medical services in this high mortality setting as well as the necessity for promoting preventive health measures.

Adolescent↗
PubMed1987

Community leadership and participation in the Saradidi, Kenya, rural health development programme.

Community participation and leadership in initiating and implementing a health development programme in Saradidi, Kenya were examined. Organization of the area into villages had to be sensitive to existing community organizational structures such as geography, religion, kinship and administrative boundaries. The lowest level government leaders did not always have the support of the community. Some groups such as women and those who were not wealthy were not always included in leadership positions; these people, however, were often most aware of certain village problems. In Saradidi, women's groups were important for community development; they supported the volunteer community health workers and carried out many village health activities. Many village health committees did not function effectively. Village health workers were supported principally by the programme centre. Village income-generating activities were not very successful. Group involvement in income raising ventures proved to be inefficient; many ended up as income draining activities. Village group income projects must be well selected relative to the skills and resources available and the ability of the product to be marketed; only exceptional ones should be encouraged. Those based at the programme's centre were more successful perhaps because of a greater investment in skills, money and marketing. Age was an important factor in accepted leadership roles in Saradidi; most effective leaders were more than 45 years of age. Village health helpers volunteered a significant proportion of their time despite poor support by village health committees and no financial remuneration. The central project structure and the training they received compensated for the lack of guidance by village health committees.

Community Health Services↗