Ecosystem impacts of three sequential hurricanes (Dennis, Floyd, and Irene) on the United States' largest lagoonal estuary, Pamlico Sound, NC.

Three sequential hurricanes, Dennis, Floyd, and Irene, affected coastal North Carolina in September and October 1999. These hurricanes inundated the region with up to 1 m of rainfall, causing 50- to 500-year flooding in the watershed of the Pamlico Sound, the largest lagoonal estuary in the United States and a key West Atlantic fisheries nursery. We investigated the ecosystem-level impacts on and responses of the Sound to the floodwater discharge. Floodwaters displaced three-fourths of the volume of the Sound, depressed salinity by a similar amount, and delivered at least half of the typical annual nitrogen load to this nitrogen-sensitive ecosystem. Organic carbon concentrations in floodwaters entering Pamlico Sound via a major tributary (the Neuse River Estuary) were at least 2-fold higher than concentrations under prefloodwater conditions. A cascading set of physical, chemical, and ecological impacts followed, including strong vertical stratification, bottom water hypoxia, a sustained increase in algal biomass, displacement of many marine organisms, and a rise in fish disease. Because of the Sound's long residence time ( approximately 1 year), we hypothesize that the effects of the short-term nutrient enrichment could prove to be multiannual. A predicted increase in the frequency of hurricane activity over the next few decades may cause longer-term biogeochemical and trophic changes in this and other estuarine and coastal habitats.

Variables affecting Army physical disability processing.

This research identifies variables affecting the length of time to process a soldier through the U.S. Army Physical Disability Evaluation System (PDES). The subjects are 8,301 soldiers whose disability records were processed in fiscal year 1996. The dependent variable examined was the average number of days a soldier remains in the disability processing system. Independent variables included age, component, compensation award, Congressional involvement, gender, grade, retirement eligibility, race, length of service, formal Physical Evaluation Board (PEB), and regional PEB. Statistical analysis using linear regression and SPSS yielded an average length of stay (ALOS) of 155 days and a range of 1 to 2,052 days. The research shows that the most significant variables affecting ALOS are Congressional involvement, component, compensation, formal PEB, and regional PEB. The authors recommend a program of disability case management and increasing emphasis on transition assistance programs to reduce ALOS in the PDES.

Attempt to correlate urine arsenic excretion with clinical course during melarsoprol therapy of patients with Rhodesian trypanosomiasis.

This study enrolled 28 CNS-involved patients with Trypanosoma brucei rhodesiense at the Kenya Trypanosomiasis Research Institute (Alupe, Kenya) to examine treatment efficacy and toxicity of melarsoprol in relation to renal excretion/dose relationships. This study complied with World Health Organization treatment recommendations, initially treating with suramin followed by three courses of melarsoprol. Traced study patients had a relapse rate of 4.1%. The toxicity and crude death rate was 7.1%. Total urine arsenic output was measured between 24 and 48 hr after the last dose for each course. The range of means of total urine arsenic output between the three treatment courses was 356-511 micrograms. There was no correlation comparing melarsoprol dose, estimated creatine clearance, or urine arsenic output. Urinary pharmacokinetic parameters are not predictive of toxicity or therapeutic efficacy.

Plasmodium falciparum circumsporozoite vaccine immunogenicity and efficacy trial with natural challenge quantitation in an area of endemic human malaria of Kenya.

It has been hypothesized that antibody induced by Plasmodium falciparum circumsporozoite protein vaccine would be effective against endemic human malaria. In a malaria endemic region of Kenya, 76 volunteers, in 38 pairs sleeping adjacently, were immunized with subunit circumsporozoite protein Asn-Ala-Asn-Pro tetrapeptide repeat-pseudomonas toxin A, or hepatitis B vaccine. After quinine and doxcycycline, volunteers were followed for illness daily, parasitemia weekly, antibody, T-lymphocyte responses, and treated if indicated. Anopheles mosquitoes resting in houses were collected, and tested for P. falciparum antigen, or dissected for sporozoites and tested for blood meal ABO type and P. falciparum antigen. Vaccine was safe, with side-effects similar in both groups, and immunogenic, engendering IgG antibody as high as 600 micrograms ml-1, but did not increase the proportion of volunteers with T-lymphocyte responses. Estimation of P. falciparum challenge averaged 0.194 potentially infective Anopheles bites/volunteer/ day. Mosquito blood meals showed no difference in biting intensity between vaccine and control groups. Both groups had similar malaria-free survival curves, cumulative positive blood slides, cumulative parasites mm-3, and numbers of parasites mm-3 on first positive blood slide, during three post-vaccination observation periods. Every volunteer had P. falciparum parastemia at least once. Vaccinees had 82% and controls 89% incidences of symptomatic parasitemia (P = 0.514, efficacy 9%, statistical power 95% probability of efficacy < 50%). Vaccine-induced anti-sporozoite antibody was not protective in this study. Within designed statistical precisions the present study is in agreement with efficacy studies in Colombia, Venezuela and Tanzania.

Impact of transmission intensity and age on Plasmodium falciparum density and associated fever: implications for malaria vaccine trial design.

To facilitate design of vaccine trials, malaria was studied in 6-month- to 6-year-old Kenyans during high (HI) and low intensity transmission seasons. During 84 days after cure, exposure to infected mosquitoes was 9-fold greater in the HI group, yet incidence of P. falciparum infection was increased only 2-fold, with no age effect. The density of recurrent P. falciparum was 14-fold greater in the HI group, and there was a striking association between age and parasitemia > or = 5000/microL. Fever was the only clinical manifestation attributable to parasitemia and only when the parasite density was > or = 5000/microL. Sixty-four percent of children with > or = 20,000 parasites/microL versus 10% with 1-4999/microL were febrile when parasitemic. Recurrent P. falciparum infection as a vaccine trial end point can be studied year-round among children < or = 6 years [corrected] in western Kenya. However, high-grade parasitemia (> or = 5000 or 20,000/microL) with or without elevated temperature will be optimally studied in the high transmission season among children < 2 years.

Plasmodium falciparum incidence relative to entomologic inoculation rates at a site proposed for testing malaria vaccines in western Kenya.

Relationships between Plasmodium falciparum incidence and entomologic inoculation rates (EIRs) were determined for a 21-month period in Saradidi, western Kenya, in preparation for malaria vaccine field trials. Children, ranging in age from six months to six years and treated to clear malaria parasites, were monitored daily for up to 12 weeks to detect new malaria infections. Overall, new P. falciparum infections were detected in 77% of 809 children. The percentage of children that developed infections per two-week period averaged 34.7%, ranging from 7.3% to 90.9%. Transmission by vector populations was detected in 86.4% (38 of 44) of the two-week periods, with daily EIRs averaging 0.75 infective bites per person. Periods of intense transmission during April to August, and from November to January, coincided with seasonal rains. Relationships between daily malaria attack rates and EIRs indicated that an average of only 7.5% (1 in 13) of the sporozoite inoculations produced new infections in children. Regression analysis demonstrated that EIRs accounted for 74% of the variation in attack rates. One of the components of the EIR, the human-biting rate, alone accounted for 68% of the variation in attack rates. Thus, measurements of either the EIR or the human-biting rate can be used to predict corresponding attack rates in children. These baseline epidemiologic studies indicate that the intense transmission patterns of P. falciparum in Saradidi will provide excellent conditions for evaluating malaria vaccine efficacy.

Preparing for the downsizing and closure of Letterman Army Medical Center: a case study.

Letterman Army Medical Center (LAMC) began a phased downsizing in July 1991 which will lead to closure by June 30, 1994. An analysis of the downsizing and closure process has yielded information which can be valuable to medical treatment facility managers faced with similar challenges in the future. By review and analysis of documentation, this case study extracted and interpreted pertinent information from historical records and from personnel involved in planning for the downsizing and closure of LAMC. This study provides managers of military hospitals that are downsizing or closing with a summary of issues for planning, compiled by their relative importance, and a description of methods employed by LAMC for managing these issues.

Prevalence of serum antibody to the type-specific glycopeptidolipid antigens of Mycobacterium avium in human immunodeficiency virus-positive and -negative individuals.

An enzyme-linked immunosorbent assay was constructed by using as antigens the type-specific immunodominant glycopeptidolipids of selected serotypes of Mycobacterium avium. This assay system was used to determine the prevalence of raised antibody levels to these antigens in groups of controls, human immunodeficiency (HIV)-negative and -positive homosexual men, and HIV-negative patients with active M. avium infections as a possible indicator of potential exposure and/or colonization by M. avium in these individuals. The results indicate that while antibody levels were raised in only 2.4% of control individuals, 33% of HIV-negative homosexual men and 44% of HIV-positive patients exhibited raised levels. Moreover, further examination of the HIV-positive group revealed no correlation between antiglycopeptidolipid antibody activity and helper T cell numbers. These data indicate that exposure to M. avium is prevalent among the homosexual male population, regardless of their HIV status. Moreover, the data are suggestive that the emergence of disseminated M. avium disease in HIV-positive patients may sometimes arise from earlier colonization, rather than as a newly acquired infection during terminal immunodeficiency.

Treatment of arsenical refractory Rhodesian sleeping sickness in Kenya.

Case histories of three Rhodesian sleeping sickness patients who relapsed after Mel-B therapy are presented. Repeated Mel-B therapy was clinically effective but not curative, and all three patients subsequently relapsed again and required further treatment.

Reversible sensorineural hearing loss in a stroke patient.

A case is presented of a patient with lateral pontine stroke which resulted in a moderate unilateral sensorineural hearing loss. ABR, word recognition scores, acoustic reflexes, neurological evaluation, and CT scan were consistent with brain stem lesion. Recovery of hearing, including acoustic reflexes and word recognition ability, occurred 2 months after the stroke.

Recurrent meningococcal meningitis with occult CSF leak.

Recurrent meningococcal meningitis was associated with a slow CSF leak in a 24-year-old man. Unique features of the case included isolation of meningococcal group 29E. We speculate that an association exists between subclinical CSF leaks and sporadic cases of meningitis.