Current and future trends in transfusion therapy.

The increase in intensive treatment for cancer has impacted blood product transfusion practices. Transfusion guidelines are primarily institution specific, but the general concepts and theories are universal. Blood product screening has decreased the risk of transfusion-acquired infections; however, the risk is not obsolete. This article reviews current approaches to platelet, white blood cell, and red blood cell transfusions, as well as risks associated with these therapies (e.g., infection and transfusion-associated graft-versus-host disease). Pertinent laboratory studies, patient assessment, blood product administration, and patient education is discussed. The current approaches to platelet, white blood cell, and red blood cell transfusions are constantly changed and evaluated. Pediatric oncology nurses must stay up to date with these changes to provide optimal patient care.

Dog bite incidence in the city of Pittsburgh: a capture-recapture approach.

OBJECTIVES: The purpose of this study was to estimate the number of dog bite injuries occurring in the city of Pittsburgh in 1993. METHODS: The capture-recapture method was used, along with long-linear modeling. Three sources were used to identify victims hospital reports, animal control reports, and police/victim reports. RESULTS: In 1993, 790 dog bites were reported. The capture-recapture method estimated that there were 1388 unreported dog bites, with an estimated incidence rate of 58.9 per 10,000. CONCLUSIONS: Dog bite is a common our preventable injury. To improve surveillance, the focus should be on educating the general public about the serious consequences of dog bite injuries.

Isolation and in vitro translation of Onchocerca volvulus mRNA.

Adult Onchocerca volvulus recovered for excised nodules by dissection or treatment with collagenase have been used as a source of RNA for in vitro translation experiments. RNA was purified using either the hot phenol/SDS procedure or the guanidine isothiocyanate protocol. Immunoprecipitation experiments performed on in vitro products demonstrate a marked heterogeneity in responses by individed human infection sera. Further immunoprecipitation experiments demonstrate cross reactivity between O. volvulus and other filarial nematodes.

Onchocerciasis transmission levels and Simulium damnosum complex biting activity at riverside and rice field sites in Sierra Leone.

Biting densities of the Simulium damnosum Theobald complex of blackflies and their levels of parasitism by Onchocerca volvulus (Leuckart) were compared at two ecologically contrasted sites in the Southern Province of Sierre Leone, West Africa: by the Tabe riverside close to Gbaiima village where onchocerciasis is hyperendemic (63.1% positive skin-snips) and in open rice fields 2 km from the mesoendemic (54.9%) village of Senehun. Using a combination of morphometric and enzyme electrophoresis techniques, the primary vector was found to belong to the S.sanctipauli subcomplex and was most probably S.soubrense 'B' (sensu Post, 1986). In the wet season biting activity took place throughout the day at the village, but had morning and evening peaks in the rice fields. Transmission of O.volvulus was detected at the village in all months except February-April, while in the rice fields it was detected only during September-November and May at one tenth the level of the village. There was a significant difference between the two sites in the proportion of parous flies carrying third stage larvae in the head, but not of other larval stages.

Epidemiological studies of onchocerciasis in forest villages of Sierra Leone.

Results are presented for five villages in the forest zone of Sierra Leone in which forest onchocerciasis was considered to be a significant health problem. All five villages were found to be hyperendemic and 85% (682/803) of persons were found to have at least one sign of onchocerciasis. The emergence of microfilariae from skin snips (iliac crest and/or canthus) or the presence of nodules accounted for 96.5% of all persons positive for onchocerciasis. The prevalence of nodules from all body sites was 70.5% and of elephantiasis, hanging groin and skin lesions (moderate and severe) was 0.4%, 0.3% and 5.3% respectively. Analysis of eye lesions (the most serious clinical manifestation of the disease) was restricted to persons aged 30 years and over since this gives a better indication of the public health importance of onchocerciasis than analysis in the overall population. This gave prevalence rates of onchocercal blindness of 4.5% (both eyes) and 2.8% (one eye only). Rates for the four potentially blinding eye lesions were sclerosing keratitis (4.1%), iritis (16.5%), optic atrophy (13.8%) and choroidoretinitis (14.4%). Rates in males were approximately twice as high as those in females.

Epidemiological studies of onchocerciasis in savanna villages of Sierra Leone.

The overall prevalence of onchocerciasis was 78% and 73% in three villages of the woodland savanna of Koinadugu and four villages of the savanna-forest mosaic of Kambia respectively. The total number of persons examined was 611. In Koinadugu the prevalence of microfilariae of Onchocerca volvulus in skin snips from the iliac crest and canthus was 51.3% and 22.5% respectively while corresponding figures for Kambia were 52.2% and 19.3%. The pattern of clinical manifestations were similar in both districts, the overall rates for nodules, skin lesions (moderate and severe) and leg elephantiasis being 53.2%, 12.5% and 0.3% respectively. No cases of hanging groin were seen. The prevalence of onchocercal eye lesions was lower in the present surveys than in our own findings in Guinea or the findings of other investigators in the Guinea or Sudan savanna of West Africa. In the present study prevalences of the fourmain blinding eye lesions in persons aged 30 years or more were sclerosing keratitis (3.7%), iritis (8.7%), optic atrophy (14.2%) and choroidoretinitis (11.3%), and the prevalence of blindness was 4.2% (both eyes) and 2.0% (one eye). Males were more commonly affected than females. Further entomological studies are needed to elucidate the relative role played by the different cytospecies of Simulium damnosum s.l. in the transmission of onchocerciasis in the savanna of Sierra Leone.

Onchocerciasis in Sierra Leone.2: A comparison of forest and savanna villages.

Very little of the original primary forest remains in Sierra Leone and the savanna is mainly woodland or a forest-savanna mosaic. The prevalence of microfilariae of Onchocerca volvulus, nodules and moderate or severe skin lesions was higher in forest than savanna villages. In forest villages the prevalence of microfilariae was 71.8% at the iliac crest, 36.6% (outer canthus), 12.8% (cornea) and 34.1% in the anterior chamber of the eye. Corresponding figures for the savanna villages were 51.9%, 20.5%, 5.6% and 21.8%. The overall prevalence of nodules in the forest and savanna was 70.5% and 53.2% respectively, while the prevalence of head and upper body nodules was 14.8% (forest) and 11.0% (savanna). The prevalence of moderate or severe skin lesions was 17.7% in forest and 13.0% in savanna villages. Lesions of the groin and scrotum were few in both zones. In persons aged 30 years or more the prevalence rates of severe eye lesions--sclerosing keratitis, iritis, optic atrophy and choroidoretinitis--were 4.3%, 16.1%, 13.9% and 14.8% respectively in forest villages. Corresponding figures for the savanna villages were 3.7%, 8.7%, 14.2% and 11.3%. Males were more commonly affected than females. At least one of these lesions was found in 32% persons in forest and 24% in savanna villages.

Onchocerciasis in Sierra Leone 3: Relationships between eye lesions and microfilarial prevalence and intensity.

The relationship between severe onchocercal eye lesions (iritis, sclerosing keratitis, optic atrophy and choroidoretinitis) and (i) the prevalence and intensity of microfilariae (mf) of Onchocerca volvulus in skin snips from the iliac crest and outer canthus, and (ii) the prevalence of mf in the cornea and anterior chamber of the eye, was studied in 1414 persons from forest and savanna villages and 312 attenders at eye clinics. Ecologically the savanna of Sierra Leone more closely resembles the forest than the dry Sudan-savanna areas of West Africa, and in persons aged 30 years or more the combined prevalence of anterior segment lesions (iritis and sclerosing keratitis) was higher in the forest villages (20.6%) than in the savanna (12.7%). The higher loads of mf found in the forest compared to savanna villages could explain these results. Prevalence rates for posterior segment lesions (optic atrophy and choroidoretinitis) were 28.1% and 22.6% in the forest and savanna respectively. Although in villages from both zones there was a close association between mf in the anterior chamber and optic atrophy, other associations between posterior segment lesions and mf were either not significant or weak. In contrast, there was a strong association between anterior segment lesions and mf in the eye and the concentration of mf at the outer canthus. This association was stronger for iritis than for sclerosing keratitis.

A histocytochemical study of the macrophages present in tissue responses to adult Onchocerca volvulus.

Immunocytochemical and histochemical properties of macrophages present in the subcutaneous chronic inflammatory responses surrounding adult Onchocerca volvulus (nodules) in human tissues were examined. Macrophages with strong non-specific esterase (NSE) and acid phosphatase (AcPase) activities but weak adenosine triphosphatase (ATPase) activity and HLA-DR expression (NSE+++, AcPase+++, ATPase-/+, HLA-DR-/+) were present in the centre of nodules. Many of the cells adhering to the surface of worms were NSE+++, AcPase+++, ATPase-, HLA-DR+++. The inner zone of the fibrous capsule of nodules contained macrophages with the profile NSE+++, AcPase-, ATPase-/+, HLA-DR-/+. A fourth type, NSE+++, AcPase-/+, ATPase-/+, HLA-DR+++, was located in the outer zone of the capsule, frequently within perivascular accumulations of macrophages, lymphocytes and plasma cells. Active fibroblasts were identified at the inner edge of the fibrous capsule by alkaline phosphatase staining. A feature of all nodules examined was the presence of lipid-filled macrophages, demonstrated by Oil Red O stain; these cells were usually situated in zones adjacent to the centre of nodules, and were of the NSE++, AcPase++, ATPase-/+, HLA-DR-/+ type. Lipid accumulation was not found to be related to the clinical status of the patients studied. The origin and functional significance of this lipid is unknown.

Surface components of Onchocerca volvulus.

A technique employing Sephadex G25 gel filtration has been developed for the rapid isolation and purification of live microfilariae of Onchocerca volvulus from subcutaneous nodules and skin samples. Microfilariae, adult worms and L3 larvae have been surface radiolabelled using the Iodogen technique. Two proteins have been characterised on the surface of uterine microfilariae: these have apparent molecular weights of 14,800 and 15,000. A MW 15,000 protein was the only molecule labelled on the surface of skin microfilariae. Ten proteins were labelled on adult male worms: these have molecular weights of 15,000, 17,500, 20,000, 22,000, 24,000, 29,000, 32,000, 37,000, 42,000, and 50,000. Some, if not all, of these proteins were also identified on female worms. Seven proteins were labelled on the surface of L3 larvae: these have molecular weights of 17,500, 48,000, 50,000, 52,000, 54,000, 57,000, and 105,000. Three of the adult surface proteins were precipitated by selected human infection serum: these are the MW 17,500, 32,000 and 42,000 molecules. The microfilarial surface proteins were not precipitated by human infection serum. The antiserum used in these experiments was shown by Western blot analysis to contain high levels of antibody with specificity for microfilarial and adult antigens. Indirect immunofluorescent assays showed these sera to contain antibody which bound to the surface of adult worms and eggs but not microfilariae. The possibility that skin microfilariae absorb host serum albumin was investigated: Western blot analysis and surface immunofluorescence assays using a specific anti-human albumin serum gave negative results. Fluorescent lectin binding studies revealed the presence of stage-specific carbohydrate moieties exposed on the surface of adult worms and eggs. Microfilariae do not have surface carbohydrate determinants.

Onchocerciasis in Sierra Leone. I. Studies on the prevalence and transmission at Gbaiima village.

A longitudinal survey--parasitological, clinical, immunological and entomological--of onchocerciasis is being conducted in Gbaiima village in Sierra Leone. The estimated Annual Transmission Potential (ATP) is 5863. More than 80% of the annual transmission occurs between October and December. Four species of the Simulium damnosum complex are known to breed in a nearby river. The relative role of these species as vectors has yet to be determined. The total population (598 persons) aged one year and over were examined. Based on microfilarial and nodular rates the prevalence of onchocerciasis was 68.6%. In persons above 15 years of age this prevalence was 88.9%. Microfilarial and nodular rates were related to age. Severe skin lesions occurred in 1.0% of persons. 24 adults (7.5%) were blind (but the cause of the blindness was not determined).

A comparative trial of praziquantel, metrifonate and niridazole against Schistosoma haematobium.

Praziquantel administered in a single oral dose of 30 mg kg-1 to subjects infected with Schistosoma haematobium produced minimal side effects and was more effective than established regimes of niridazole and metrifonate. Praziquantel should prove a major tool in schistosomiasis control programmes.

The examination--time/dose interval in the provocation of nocturnally periodic microfilariae of Wuchereria bancrofti with diethylcarbamazine and the practical uses of the test.

The administration of diethylcarbamazine (DEC) in the daytime in areas where microfilariae (mf) of Wuchereria bancrofti and Brugia malayi exhibit nocturnal periodicity provokes mf to enter the peripheral blood. The importance of relating the dose of DEC and time when the blood specimen is taken is emphasized. The main practical uses of this provocative day test are as a routine diagnostic tool, in estimating prevalence and density of mf in a community, as a preliminary screening method for assessing potential filaricides nd in evaluating the parasitological response to mass chemotherapy.

Chemotherapy with diethylcarbamazine and levamisole in Bancroftian filariasis.

Field trials in which spaced doses of DEC were given once weekly, monthly or bi-monthly (or combinations of these intervals) cleared microfilariae (mf) of Wuchereria bancrofti from the blood in 78% if persons examined at six months. This reduction of microfilaraemia was maintained at a four years follow up examination. All regimens were well tolerated. In areas where mf rates were less than 12% a total dose of 36-48 mg/kg of DEC was effective. Higher doses (72 mg/kg) are required where mf rates are greater than 20%. The results of administering an oral dose of levamisole (3 mg/kg) prior to daily doses of DEC (6 mg/kg/day/7) were no better at the 2 month examination compared to the results following a similar regimen of DEC without prior administration of levamisole. Retreatment with DEC (6 mg/kg/day/7) of persons having microfilaraemia four years after initial treatment with this drug resulted in mf clearance in 94% of subjects.

A note on drug trials in schistosomiasis.

In schistosomiasis, if the subjects of drug trials are in contact with potentially contaminated water, then differences in the chemotherapeutic response to the same dose of a drug given in the same endemic area in different seasons, may be related to different levels of transmission. Because a reduction in egg excretion may occur from causes other than chemotherapy, moderate antischistosomal activity of a drug cannot be concluded in the absence of a control group.