[Visitor returning from the tropics 1991].
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Humans↗
Biomedical subjects
C Hatz
Publications and source records attributed to C Hatz.
Community-based questionnaires and health statistics as tools for the cost-efficient identification of communities at risk of urinary schistosomiasis.
Self-administered questionnaires, distributed by existing administrative channels to village party chairmen, head-teachers and schoolchildren, showed good diagnostic performance for the qualitative assessment of urinary schistosomiasis endemicity. At a cost 34 times below that of the WHO-recommended parasitological screening strategy, the schoolchildren's questionnaire allowed the screening of 75 out of 77 schools of a rural Tanzanian district in six weeks, and the exclusion of schools not at high risk for urinary schistosomiasis with over 90% confidence. The headteacher and party questionnaires made it possible to assess the perceived importance of a spectrum of diseases and symptoms, among which was schistosomiasis. The priority rank of schistosomiasis control was strongly correlated with the prevalence rate of the disease in the community. The questionnaires also looked for the prioritization of health among other community issues and thus contributed important information for planning at district level. Standardized monthly disease reports, sent by all primary health services, were also analysed. They allowed a zonal schistosomiasis endemicity classification.
Adolescent↗
Rapid, low-cost, two-step method to screen for urinary schistosomiasis at the district level: the Kilosa experience.
The operational and diagnostic performance of a two-step method for the cost-effective screening of urinary schistosomiasis was investigated in the Kilosa District of east-central Tanzania. In the first step a simple questionnaire was administered to 15,073 primary schoolchildren by their class teachers over a 4-week period. The answers to the questionnaires had a high negative predictive value for schistosomiasis, and this permitted the safe exclusion of schools where the risk of the disease was low. In the second step, the head-teachers of the 49 high-risk schools and of 26 low-risk schools were instructed on the use of reagent sticks to detect haematuria. Each head-teacher then performed this test on 80 children selected at random in their schools (5750 children were screened within 6 weeks). Crosschecks of the results in 18 schools confirmed the reliability of the head-teachers' testing and their findings were therefore used to prepare an epidemiological map of the district and to arrange for treatment of positive children. This two-step approach relied entirely on the existing school system and permitted screening of a rural district of area 15,000 km2 (population, 350,000) over a 4-month period at a cost of only US$3000.
Child↗
Control of morbidity due to Schistosoma haematobium on Pemba Island: egg excretion and hematuria as indicators of infection.
The variability of Schistosoma haematobium egg excretion using a quantitative syringe filtration technique and the variability of hematuria detected visually and by reagent strips were studied in a population of 520 subjects from the village of Pujini (Pemba Island, Zanzibar, Tanzania) for 6 consecutive days. A high degree of day-to-day variability of egg excretion within subjects was found both in the whole population and in the 5-19 year age group. Subjects with 1 urinary egg count of greater than or equal to 50 eggs/10 ml urine were not similarly classified in 36-61% of the other 5 examinations and 4-16% of their other examinations were negative. Gross hematuria had a specificity of almost 100%, when related to a positive filtration on any day, and was closely related to egg counts of greater than or equal to 50 eggs/10 ml urine. The finding of a strongly positive reaction for hematuria on a given single day was closely associated with the subject having a high egg count (greater than or equal to 50 eggs/10 ml urine) on at least one of the 6 days of the study. At the primary health care level, single highly positive semiquantitative values for hematuria were a more useful diagnostic indicator than a single egg count to select patients with heavy infections for selective population chemotherapy.
Adolescent↗
Measurement of schistosomiasis-related morbidity at community level in areas of different endemicity.
Among the indicators of schistosomiasis morbidity currently used in control programmes, ultrasound has been found to be a safe, non-invasive and efficient technique for detecting schistosomiasis-related lesions and for assessing the effect of treatment on their resolution. Three case-studies from East Africa, in areas of different endemicity for Schistosoma haematobium, using ultrasound are described and their results related to indirect measurements of the disease (e.g., haematuria, egg counts). This review reveals that cross-sectional ultrasound surveys can be used to quickly assess subsamples of populations in areas of different endemicity, in order to make decisions about sampling strategies in control programmes. The association between the intensity of infection and urinary tract abnormalities is reviewed and evaluated. One case study provides information on the resolution of S. haematobium-related uropathy after treatment; this information is crucial in order to maintain low levels of morbidity in a community. The role of ultrasound is further discussed, particularly as a tool to complement and validate indirect morbidity control measurements. The validation of such indirect measurements for use as a basis for public health decisions is important because they can be carried out by existing health care services in many areas.
Adolescent↗
Field diagnosis of urinary schistosomiasis by multiple use of nuclepore urine filters.
It has been recognized recently that the standard field technique for the diagnosis of urinary schistosomiasis, urine filtration using reusable polyamide mesh filters, may give false-positive findings because filters cannot be washed adequately in all circumstances. In this study the alternative filtration method using polycarbonate membrane filters was tested, and the same problem existed. A variety of more vigorous washing procedures was field tested with the conclusion that polycarbonate filters can be washed adequately for reuse by a simple procedure that includes boiling for 5 min in tap water prior to washing with detergent.
Animals↗
[Etiology of atypical pneumonias. A serological study on 1494 patients].
In a retrospective study the serological results from 1494 patients with community-acquired pneumonia were evaluated. An infectious etiology was found in about 40% of the cases. The majority of pneumonias was caused by Mycoplasma pneumoniae and by influenza virus type A, whereas Legionella pneumophila was the fifth most frequent pathogen. In the second part of the study, 13 hospitalized patients with community-acquired pneumonia were investigated by the whole panel of routinely used microbial methods. The etiological agent was found serologically in 3 cases and in one case by cultivation. These results suggest that the determination of serum antibodies against pathogens is frequently more useful than is generally assumed, although the yield of positive results is dependent on the epidemiological situation. The detection of elevated complement-fixing titers or specific IgM antibodies often leads to diagnosis from the first serum examined.
Adolescent↗
Isolation and characterization of fructose diphosphate aldolase from Pisum sativum.
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Aldehyde-Lyases↗
Aldolase activity in chloroplasts of Spinacia oleracea.
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Chloroplasts↗
In vitro resistance patterns of Plasmodium falciparum to chloroquine--a reflection of strain-specific immunity?
Studies in vitro among children on the response of Plasmodium falciparum to chloroquine were conducted as part of the national long-term monitoring of drug resistance in a holo- to hyperendemic malarious area of Tanzania between 1983 and 1989. Overall, no significant increase in chloroquine resistance was observed. However, in children under 5 years old resistance increased during this period, whereas in schoolchildren resistance decreased from 1986 to 1989. A hypothesis based on antigenic differences between resistant and sensitive strains is proposed to explain this age-specific pattern. If immunity develops principally against the most frequent parasite strains, then as it develops the numbers of the most frequent strains will be reduced, whilst, the rare strains may become predominant and thus be detected in the blood of immune patients. Thus, in an endemic area, the observed resistance pattern in non-immune infants will differ from that in immune schoolchildren, as was observed in the present study. These findings may have important implications for the control of malaria and the development of vaccines.
Adolescent↗
A stable, oligosymptomatic malaria focus in Thailand.
Blood from most of the 250 residents of a non-migratory farming village in south-eastern Thailand was visually examined for malaria parasites monthly for 2 years. Nearly 97% of the population had at least one (median = 5) patent Plasmodium falciparum infection per year; 72% had one due to P. vivax (median = 1). This contrasted with a slide positivity rate of 17% calculated from 12 months of passive case detection before the study began. Children 1-9 years old had the highest mean monthly prevalence (51%) and highest geometric mean density (10/500 white blood cells) of P. falciparum. Fewer than half the expected number of mixed infections were found but these were more common at high densities of P. falciparum. Individuals over 19 years old comprised 52% of the population but accounted for only 18% of P. vivax and 32% of P. falciparum gametocytaemias. Fever rates were marginally higher in those below 10 years old (8%) but occurred with equal frequency in those with patent infections or negative. The spleen rate (89% stage 1) was 24% in those under 15 years old and 7% in those older. No malaria mortality was seen P. falciparum cases treated for 10 d with quinine+tetracycline (QT) cleared the infection as often as those given one dose of mefloquine+sulfadoxine+pyrimethamine (MSP); both treatments reduced densities in cases not cured. Apparently unsupervised compliance was no better with MSP than with QT. The role played by hyperendemic, cryptic foci in Asian epidemics of malaria may have been underestimated.
Age Factors↗
Ultrasound scanning for detecting morbidity due to Schistosoma haematobium and its resolution following treatment with different doses of praziquantel.
A study to assess the resolution of urinary tract morbidity due to Schistosoma haematobium was conducted on 2 cohorts of schoolchildren attending neighbouring schools in Kilombero District, southern Tanzania. Schoolchildren were screened for S. haematobium infection using the standard World Health Organization filtration technique and subsequently examined for urinary tract pathology using a portable 3.0 MHz sector scanner (Siemens Sonoline 1300). Treatment with praziquantel was given to all infected children. Children with observed urinary tract pathology received either 20 (n = 52) or 40 (n = 79) mg/kg body weight and were sonographically re-examined one, 2, 3 and 6 months following treatment. Geometric mean outputs of 21 and 19 eggs/ml of urine were detected in the 2 cohorts before treatment. Urinary tract pathology correlated positively with egg output (chi 2, P = 0.02) and microhaematuria (P = 0.0001). Bladder (wall irregularities and polyps) and kidney (congestive changes) pathologies were found in 81% and 36%, respectively, of the group that received 20 mg/kg of praziquantel, and in 78% and 46% of the group that received 40 mg/kg. Six months after treatment, 90.4% and 88.0% parasitological cure rates were obtained using 20 or 40 mg praziquantel/kg body weight. The respective pathology clearances were 88% and 91%. 20 mg/kg of praziquantel was as effective with regard to cure rates and reversibility of morbidity as 40 mg/kg.
Adolescent↗
Imported schistosomiasis in Europe: sentinel surveillance data from TropNetEurop.
BACKGROUND: Schistosomiasis is a major parasitic disease, increasingly imported into temperate climates by immigrants from and travelers to endemic areas. METHOD: To generate valid data on imported infectious diseases to Europe and to recognize trends over time, the European Network on Imported Infectious Diseases Surveillance (TropNetEurop) was founded in 1999. Three hundred and thirty-three reports of schistosomiasis were analyzed for epidemiologic and clinical features. RESULTS: Male patients accounted for 64% of all cases. The average age of all patients was 29.5 years. The majority of patients were of European origin (53%). Europeans traveled predominantly for tourism (52%). Main reasons for travel for people from endemic areas were immigration and refuge (51%) and visits to relatives and friends (28%). The majority of infections were acquired in Africa; 92 infections were clearly attributable to Schistosoma haematobium, 130 to Schistosoma mansoni, and 4 to Schistosoma intercalatum. Praziquantel was the only treatment used. No deaths were recorded. CONCLUSION: TropNetEurop sentinel provides valuable epidemiologic and clinical data on imported schistosomiasis to Europe.
Adolescent↗
[Vulvar lesion in urogenital schistosomiasis (S. haematobium)].
Genital schistosomiasis must be considered in women from endemic areas presenting with the following signs and symptoms: Vulvar papules, swelling or tumour irregular vaginal bleeding infertility, ectopic pregnancy Urinary tract schistosomiasis can affect the lower and upper female genital tract.
Adult↗