Independent evaluation of the Nigrosin-Eosin modification of the Kato-Katz technique.
(1/190)
A new modified quantitative Kato-Katz thick-smear technique for the detection of helminth eggs in faeces preserves hookworm eggs unaltered for a long time, while with the classic Kato-Katz technique, they disappear after approximately 2 h in tropical climates and thus slides must be read within hours after sample collection. For an independent comparison of these two laboratory techniques, faecal smears from 263 school children were examined in two surveys and prevalence, intensity of infection and costs of surveys calculated. There was no statistical difference between the methods in detecting prevalence and stratification of the sample in different classes of intensity. While there was no statistical difference for the arithmetic mean of the epg for T. trichiura and only a small difference for A. lumbricoides (P=0.04), we observed a highly significant difference for hookworm mean intensities of infections (P<0.001). From the public health viewpoint both methods provided similar results, but due to its simplicity and widespread use the classical Kato-Katz technique remains first choice for community investigation of soil-transmitted nematodes. However, the Nigrosin-Eosin approach has several advantages and can be a valuable alternative in certain circumstances. (+info)
Developmental regulation of SR protein phosphorylation and activity.
(2/190)
Serine/arginine-rich splicing factors (SR proteins) are substrates for serine phosphorylation that can regulate SR protein function. We have observed gross changes in SR protein phosphorylation during early development coincident with major zygotic gene activation in the nematode Ascaris lumbricoides. These differences correlate with large-scale changes in SR protein activity in promoting both trans- and cis-splicing. Importantly, inactive early stage extracts can be made splicing competent on addition of later stage SR proteins. These data suggest that changes in SR protein phosphorylation have a role in the activation of pre-mRNA splicing during early development. (+info)
Genetic analysis of susceptibility to infection with Ascaris lumbricoides.
(3/190)
Epidemiologic studies of helminthic infections have shown that susceptibility to these parasites frequently aggregates in families, suggesting the possible involvement of genetic factors. This paper presents a genetic epidemiologic analysis of Ascaris lumbricoides infection in the Jirel population of eastern Nepal. A total of 1,261 individuals belonging to a single pedigree were assessed for intensity of Ascaris infection at two time points. Following an initial assessment in which all individuals were treated with albendazole, a follow-up examination was performed one year later to evaluate reinfection patterns. Three measures of worm burden were analyzed, including eggs per gram of feces, direct worm counts, and worm biomass (weight). For all traits, variance component analysis of the familial data provided unequivocal evidence for a strong genetic component accounting for between 30% and 50% of the variation in worm burden. Shared environmental (i.e., common household) effects account for between 3% and 13% of the total phenotypic variance. (+info)
A controlled evaluation of two school-based anthelminthic chemotherapy regimens on intensity of intestinal helminth infections.
(4/190)
BACKGROUND: School-based deworming programmes have been promoted as a cost-effective strategy for control of nematode infection in developing countries. While numerous efficacy studies have been conducted, there is little information on actual programme effectiveness in areas of intense transmission. METHODS: A randomized trial of a school-based deworming programme was conducted in 12 primary schools on Pemba Island, Zanzibar. Four schools each were randomized to control, twice a year deworming with single dose mebendazole or three times a year deworming. Baseline and 12-month follow-up data on helminth infection using the Kato-Katz technique, demographic information and nutritional status were collected on 3028 children from March 1994 to May 1995. RESULTS: Intensity of infection measured as eggs per gram of faeces (epg) declined significantly for Ascaris lumbricoides, Trichuris trichiura and hookworm infections in both treatment groups. A. lumbricoides infection intensity declined 63.1% and 96.7% in the twice and three times per year treatment groups compared to the controls. T. trichiura infection intensity declined 40.4% and 75.9% respectively and hookworm intensity declined 35.3% and 57.2% respectively compared to control schools. CONCLUSIONS: These results suggest that school-based programmes can be a cost-effective approach for controlling the intensity of intestinal helminth infection even in environments where transmission is high. (+info)
SR proteins are required for nematode trans-splicing in vitro.
(5/190)
SR (ser/arg) proteins have been shown to play roles in numerous aspects of pre-mRNA splicing, including modulation of alternative splicing, commitment of substrates to the splicing pathway, and splice site communication. The last of these, splice site communication, is particularly relevant to trans-splicing in which the 5' and 3' exons originate on separate molecules. The participation of SR proteins in naturally occurring, spliced leader RNA-dependent transsplicing has not been examined. Here, we have isolated SR proteins from an organism that performs both trans- and cis-splicing, the nematode Ascaris lumbricoides. To examine their activity in in vitro splicing reactions, we have also developed and characterized an SR protein-depleted whole-cell extract. When tested in this extract, the nematode SR proteins are required for both trans- and cis-splicing. In addition, the state of phosphorylation of the nematode SR proteins is critical to their activity in vitro. Interestingly, mammalian (HeLa) and A. lumbricoides SR proteins exhibit equivalent activities in cis-splicing, while the nematode SR proteins are much more active in trans-splicing. Thus, it appears that SR proteins purified from an organism that naturally trans-splices its pre-mRNAs promote this reaction to a greater extent than do their mammalian counterparts. (+info)
Immunochemical characterization and diagnostic potential of a 63-kilodalton Schistosoma antigen.
(6/190)
Schistosoma circulating antigens were used for the detection of active infection. Anti-S. mansoni IgG2a monoclonal antibody (MAb) designated C5C4 was generated. The target epitope of this MAb was detected in adult worms, eggs, and cercariae antigenic extracts of S. mansoni and S. haematobium, had a molecular size of 63 kD, and was not detected in Fasciola hepatica and Ascaris. In addition, a 50-kD degradation product was identified only in the urine of infected individuals. Analysis by high-performance liquid chromatography of the purified antigen demonstrated only one peak. The 63-kD antigen was characterized as a protein containing 40.4% hydrophobic, 7.5% acidic, and 8.8% basic amino acids. The C5C4 MAb was used in a Fast Dot-ELISA for rapid and simple diagnosis of human schistosomiasis. The 63-kD circulating antigen was detected in 92% of urine samples from 330 S. mansoni-infected individuals, with 16% false-positive results among 130 noninfected individuals. (+info)
Clinical features and management of biliary ascariasis in a non-endemic area.
(7/190)
Biliary ascariasis is common in certain geographical areas of the world. In India, it is common in the Kashmir valley and only stray cases have been reported from other parts of the country. Between January 1995 and May 1997, 14 patients with biliary ascariasis were seen at our centre, which is more than 1000 km from the Kashmir valley. The mean (+/- SD) age of the patients was 31.7 (+/- 6.1) years and all were females. None of them had been to a place known to be endemic for biliary ascariasis. Four patients presented with acute cholangitis, eight with acute abdominal pain and vomiting, and the remaining two were diagnosed incidentally during surgery for gallstone disease. Barring these two patients, ultrasound examination of the abdomen diagnosed the condition accurately. In 10 patients, a part of the worm was visible outside the papilla of Vater. The roundworm was caught in a Dormia basket and could be extracted in nine patients. In one patient the worm migrated inside the bile duct while it was being caught in a Dormia basket. In this and two other patients, in whom the worm had migrated completely inside the bile duct, worms were removed with the help of a Dormia basket after endoscopic sphincterotomy. There were no complications of endoscopic therapy. In the two patients in whom biliary ascariasis was detected during surgery, the worms were removed after choledocholithotomy. On a mean follow-up of 13.8 months, only one patient had a recurrence of biliary ascariasis. It is concluded that biliary ascariasis is not an uncommon disease and must be considered as a possibility in patients presenting with acute cholangitis and biliary pain even in a non-endemic area. Ultrasonography is an excellent diagnostic tool and endoscopic management is very effective and safe in the treatment of these patients. (+info)
A 74-year-old man was admitted to our hospital with frequent right flank pain. The multiple multilocular hepatic abscesses were revealed by computed tomography. Radiographs following a barium meal showed a linear filling defect in the ileum consistent with ascariasis. One day after treatment with pyrantel pamoate, an Ascaris was passed in the stool. The pyogenic hepatic abscesses gradually healed with both antibiotics and continuous drainage. After 2 months, he was discharged. In this case, the pyogenic hepatic abscesses were thus considered to have been caused by an inflammation which spread through the portal vein. (+info)