Epidemiological studies on jute diseases

Summary Hyphae of M. phaseoli failed to grow on unsterilized natural soil and were completely lysed within 4 days of exposure. Germination of sclerotia in natural soil was inhibited indicating soil fungistasis. Lysis of mycelium and inhibition of germination of sclerotia could be annulled by addition of various organic nutrients and fertilizers to natural soil or by autoclaving the soil. Germination of dormant sclerotia in natural soil was stimulated by root-exudates of host and non-host plants. Population of sclerotia buried in unsterilized natural soil gradually declined and after 15 months only 35 per cent of the initial number could be recovered; more than 80 per cent of these germinated when nutrients were added. Data suggest poor saprophytic ability of M. phaseoli in mycelial form and the involvement of dormant sclerotia in the survival of the organism in soil.     

Epidemiological prenatal ultrasound studies

Epidemiological studies have indicated no association between diagnostic ultrasound exposure during pregnancy and childhood malignancies. Diagnostic ultrasound imaging does not seem to influence birth weight, whereas frequent Doppler ultrasound was associated with reduced birth weight in one study. Most experts do not believe that ultrasound exposure during pregnancy is associated with reduced birth weight. There are no confirmed statistically significant associations between ultrasound and dyslexia and neurological development during childhood. However, two randomised controlled trials and two cohort studies have been unable to rule out a possible association between ultrasound and left-handedness among males.     

Epidemiological studies on caprine arthritis-encephalitis virus infection in Jordan

To investigate the seroprevalence of, and risk factors for, caprine arthritis-encephalitis virus (CAEV) infection in different breeds of goats in Jordan, sera from 1100 goats from three different geographical regions in Jordan were analyzed. Prevalence of antibodies to CAEV was determined using a competitive ELISA test. A semi-structured questionnaire was used to collect information on herd health and management. Questionnaire data were tested in a multivariable logistic regression model to elucidate risk factors associated with CAEV seropositivity. In addition, the incidence of CAEV antibodies was investigated in six goat herds located in the northern part of Jordan. Out of the 69 goat herds investigated, 16 (23.2%) had antibodies against CAEV. Individual goat true seroprevalence to CAEV was 8.9%. The highest CAEV seroprevalence was observed in goats older than 3-years and younger than 6-years of age. The seroprevalence of CAEV in goats was significantly higher (P < 0.05) in the northern part of Jordan than that in central or southern parts of Jordan. The multivariable logistic regression model identified large herd size (OD = 2.0; 95% CI: 1.1, 2.7), addition of new animals to the herd (OD = 1.3; 95% CI: 0.3, 1.6) and contact with other goat herds (OD = 1.1; 95% CI: 0.9, 2.0) as risk factors for CAEV seropositivity. The incidence of CAEV seropositivity in the six herds monitored in the northern part of Jordan ranged from 2.4 to 5.3%.     

Epidemiological and clinical studies on optimal nutrition in diabetes

There would seem to be little doubt that a diet high in fiber-rich carbohydrate can improve diabetic control and reduce levels of LDL cholesterol when compared with the more traditional low carbohydrate-high fat diabetic diet. The abnormalities of platelet function in diabetes and their association with certain essential fatty acids suggest that attention to the nature of the fat composition of the diet may be equally relevant in attempts to reduce the frequency of both micro- and macrovascular complications of diabetes. Only a very limited number of intervention studies have been carried out. More information is urgently required concerning the effects of modifying the fatty acid composition of the diabetic diet.     

Epidemiological and linkage studies on Huntington's disease in Italy

Summary The results of an epidemiological survey on Huntington's disease in the Lazio Region, Central Italy, and of linkage studies in a subset of families are reported. From a total of 99 ascertained families and 491 patients, a prevalence of 25.6 × 10–6 was obtained, with distributions of age at onset and age at death similar to those described in the literature. No relationship with the sex of the transmitting parent was observed. Analysis of 10 chromosome 4 restriction fragment length polymorphisms in 11 families showed consistent linkage between the genetic loci D4S10, D4S43 and D4S95, and the disease. A recombination rate of 0.08 for D4S10 markers was obtained in this sample. Allelic frequencies of DNA markers in the general population are also reported.     

Epidemiological studies on the stunt disease of highbush blueberry

Population levels of Scaphytopius spp., possible sharpnosed leafhopper vectors of blueberry stunt disease (BBSD), were monitored during 1989,1990 and 1991, using yellow sticky traps and a D-Vac power aspirator. Scaphytopius magdalensis (Prov.), S. frontalis (Van D.) and 5. acutus (Say) had two population peaks, one after the petal fall stage and a larger second peak in late Summer to early Autumn. Healthy cv. Bluecrop highbush blueberry (Vaccinium corymbosum L.) plants were placed under stunt-diseased bushes in the field for 2-wk periods during 1989 and 1990. These plants and some of the leafhoppers trapped during 1990 and 1991 were tested for mycoplasma-like organism (MLO) infection with a DNA probe that detected BBSD-associated MLO. The percentage of plants and the number of Scaphytopius spp. that were MLO-positive tended to follow the same bimodal distribution found in the population studies. BBSD transmission tests were performed with Scaphytopius spp. collected from the field. Stunt-related MLO transmission was achieved with S. magdalensis, S. acutus and 5. frontalis.     

Therapeutic studies in hyperthyroidism; use of radioactive iodine

Of 112 patients with hyperthyroidism who were treated with radioactive iodine, 110 were relieved of the disease. Nine had transient hypothyroidism. Twelve had permanent hypothyroidism. No other adverse effects that could be attributed to radioactive iodine were noted.     

Epidemiological studies on echovirus type 18 infection in Toyama Prefecture

Echovirus type 18 (echo 18) was isolated from six aseptic meningitis children in Fukumitsu-machi, Toyama Prefecture, from July to August, 1980. This was the first virologically-confirmed epidemic of aseptic meningitis due to echo 18 in Japan. Epidemiological studies on the prevalence of this virus among the inhabitants in Toyama Prefecture were also performed. The results are summarized as follows. (1) Significant increases in neutralizing antibody titers against echo 18 were observed in all the paired sera of aseptic meningitis patients from whom echo 18 was isolated. (2) In October, 1980, echo 18 was also isolated from healthy children or from infants suffering from gastroenteritis in other areas of Toyama Prefecture. (3) Among the sera collected from 50 children (aged smaller than or equal to 12) in Fukumitsumachi in December, 1980, neutralizing antibodies against echo 18 were detected only in the younger groups (aged smaller than or equal to 8), 58.9% of these age groups showing a titer of 4 or higher. (4) Another epidemic around 1963 by echo 18 in Toyama Prefecture was retrospectively suggested by the examinations of sera collected in 1978 and 1981 from inhabitants in various areas of Toyama Prefecture. (5) Neutralizing antibody titers against the strain isolated, No. 35'80, were significantly higher than those against strain 'Metcalf,' the prototype of echo 18, in most sera including both aseptic meningitis patients and healthy inhabitants.     

Epidemiological studies on host animals of tsutsugamushi disease in Korea

Epidemiological studies on host rodents of tsutsugamushi disease were carried out during the period of July-September 1990 at nine localities of central Korea. Among total 111 wild rodents trapped by the modified Sherman live traps, 103 were Apodemus agrarius (92.8%), seven were Crocidura lasiura (6.3%) and one was Microtus fortis (0.9%), showing 24.0% of trapping rate in winter, 11.7% in spring, 11.2% in summer and 12.0% in autumn. Out of 103 A. agrarius 84 were parasitized by chiggers, showing 81.6% of the infestation rate and 43.0 of the chigger index. The antibody positive rate of A. agrarius sera to Rickettsia tsutsugamushi was significantly variable by locality, being in the range of 0-78.6%. The seasonal change of the antibody positive rate at Dorai 5-ri, Goyang-gun was 75.8% in average during November-March, decreased to 30.3% in April and further decreased to 13.3% in average during May-August. Among 33 antibody positives, 31 were Karp strain and two were Gilliam. Seven Crocidura lasiura sera showed all negative. R. tsutsugamushi organisms were isolated from three A. agrarius out of 94 mice tested, showing 3.2% of the infection rate.     

Epidemiological and clinical studies of ovine caseous lymphadenitis

A field survey was undertaken, to determine epidemiological, clinical and biological data on Ovine Caseous Lymphadenitis disease in 54 flocks originated from Sfax area in Tunisia. The mean morbidity rate of the cutaneous form was 5.1%. This form affected sheep over 3 months and under 2 years old. On the other hand, the mean morbidity rate of the visceral form, encountered in abattoirs, was 11.02%. The clinical aspect of the superficial (or cutaneous) form was often corresponding to one abscess, located particularly in the lymphatic nodes of the animal's head; while visceral (or internal) form of the disease was represented by the presence of a unique abscess found in the pulmonary lymphatic nodes. The macroscopic aspect of lesions showed that the size of abscess was comprised between 4 and 10 cm in diameter. At the cut, colour of the pus was white yellowish to yellow greyish with a fluid or a thick aspect like onion peels; pus was microscopic. Lesions were characterised by a fibrous shell, a pyogenic membrane and a necrotic center. Bacteriological research revealed that Corynebacterium pseudotuberculosis was the pathogen the most frequently isolated, followed by Staphylococcus aureus subsp anaerobius which was particularly found in sheep aged between 3 months and 2 years old.     

Epidemiological studies of Colletotrichum gloeosporioides disease of cocoa

The intensities of foliar infection (leaf blight and shot hole) and pod rot, caused by Colletotrichum gloeosporioides, were recorded from a cocoa-areca mixed garden and a cocoa-monocrop garden during 2 years. The intensity of pod rot was recorded from both the gardens. The intensities of leaf blight and shot hole gradually increased from July, reached a peak during September-November, decreased thereafter and reached the lowest level during April-June. Increase in leaf infection was associated in both plantings and in both years with the period of rain (June-November). The phylloplane population of C. gloeosporioides also increased during June-November when the temperature tended to be low and constant with high rainfall and relative humidity. During this period there were few susceptible stages of pods (cherelles and young pods) and pod infection was very low. Nearly mature pods were free from infection. I n both years, pod infection was more in the cocoaareca mixed garden than' in the cocoa-monocrop; it was observed during January-May, when the susceptible stages were mostly prevalent but when the C. gloeosporioides population was low and the climatic factors appeared to be relatively unfavourable. This may be one reason for the lesser incidence of pod rot when compared to foliar disease.     

Epidemiological studies of neural tube defects in Newfoundland

A 9-year survey of neural tube defects in Newfoundland showed (1) evidence for secular variation, with a peak in 1980, but no general downward trend as seen in some other populations; (2) significant geographic variation which did not correlate with hardness or nitrate content of the lake water; (3) a tendency for the proportion of females among anencephalic births to increase with increasing frequency of anencephaly among geographic regions. This supports previous evidence for a female-specific contribution to the causes of increased liability to neural tube defect.     

Epidemiological studies regarding the effects of air pollution

Studies on large samples of the population are an indispensable prerequisite for investigations into the validity and reliability of threshold levels stipulated for atmospheric pollutants purity under real conditions. Children represent suitable groups for such studies, also in the context of meaningful and effective prophylaxis. Epidemiological studies conducted over several years show that there are differences between the anthropometric, hematological and immunological parameters of subjects living in regions with major pollution loads and in so-called "clean air" regions. Conclusions are drawn regarding the work performed by national hygiene authorities, and a method is proposed for the continuation of epidemiological studies in qualitatively and quantitatively differently loaded regions as a contribution to establishing a uniform register of effects.