Cryoglobulins in Schistosoma haematobium infection

The sera of school children with Schistosoma haematobium infection were tested for the presence of cold-insoluble immune complexes "the cryoglobulins". Two different methods were used: the standard macro-technique and the micro-adaptation technique. On using the standard macro-technique, 40 (32.8%) out of 122 schistosomiasis patients and 6 (7.5%) out of 80 control children were positive for cryoglobulins. Using the micro-adaptation technique, the corresponding numbers were 47 (38.5%) and 8 (10%), respectively. A comprehensive medical examination was carried out before treatment. After treatment with metrifonate (Bilarcil) the quantity of cryoglobulins and the number of children with cryoglobulins were significantly reduced to 12 (9.8%) when using macro-technique, and to 15 (12.3%) with micro-adaptation technique, thus suggesting a possible relationship of cryoglobulinaemia with urinary schistosomiasis. There was a significant difference in the number of sera found positive by the two techniques (X2 = 0.875, P less than 0.1).     

在安哥拉感染埃及血吸虫的输入性病例1例

患者男性,37岁,陕西省人,于2005年3月-2006年1月在非洲安哥拉从事铁路建设后勤工作,期间曾在当地湖中游泳及垂钓。回国后,于2006年3月开始出现无痛性血尿,尿线流畅,为终末血尿。血尿量约2～3 ml,无尿频、尿急、尿痛等。上述血尿间断出现,无明显规律,共发生10余次。病初曾用消炎药等输液治疗,效果不佳。于4月曾行膀胱镜检查,未明确诊断。5月初入西安市西京医院泌尿外科,膀胱镜检查并行活检查见虫卵。根据流行病学史,怀疑为埃及血吸虫卵,遂转入西安市唐都医院传染科。体查:体温36.7℃,全身未见皮疹及出血点,肝脾肋下未触及,肝肾区无叩痛。血常规检查:白细胞为7.11×109/L,中性粒细胞为0.47。嗜酸粒细胞为0.132(绝对值为0.94×109/L),均明显偏高。尿液检查,尿酸为368μmol/L,尿素为5.22 mmol/L,肌酐为91μmol/L,均属正常范围。粪便检查,未发现埃及血吸虫卵。收集50 ml尿     

Schistosoma haematobium infection and haemoglobin concentrations in a Gambian community

Specimens of urine and blood were collected from as many members as possible of a community living in an area of urinary schistosomiasis in The Gambia. The light infections found in many of the subjects appeared to have little or no effect of haemoglobin levels, but some of the intense infections were associated with reduced haemoglobin levels. Significant differences in haemoglobin levels between ova-positive and ova-negative subjects were apparent only in males aged from 15 to 44 years, and significant differences in the prevalence of anaemia between groups with different egg counts were apparent only in children aged from five to seven years and from eight to 14 years.     

Daily urinary protein loss in Schistosoma haematobium infection

Proteinuria was studied in 128 children aged 6 to 18 years with Schistosoma haematobium infection in the People's Republic of Congo. Urinary protein concentration in spontaneously voided midday urine of patients with greater than 100 ova/10 ml was significantly higher than in 24-hr urine specimens. Median daily urinary protein loss in patients with moderate intensity of infection (100-350 ova/10 ml) was 300 mg and 584 mg/1.73 m2 body surface in heavily infected patients (greater than 350 ova/10 ml). A significant correlation existed between egg excretion at noon and protein concentration in spontaneous urine samples as well as daily urinary protein loss (r = 0.76 and r = 0.68, respectively). Heavily infected patients had a daily protein loss of up to 3.3 g/1.73 m2, total serum protein and albumin concentration, however, were within normal limits. This may indicate adaptive mechanisms in patients with urinary schistosomiasis and high proteinuria which maintain a balanced serum protein concentration.     

Bulinus nyassanus is an intermediate host for Schistosoma haematobium in Lake Malawi.

At Cape Maclear on the Nankumba Peninsula, close to the southern end of Lake Malawi, Schistosoma haematobium is highly prevalent in the local people and many tourists become infected with this parasite each year. A 'Bilharzia Control Programme' was initiated in this area in August 1998, as a development collaboration between the Government of Malawi, the Danish Agency for Development Assistance (Danida), and the Danish Bilharziasis Laboratory. Although Bulinus globosus is a known host for S. haematobium, B. nyassanus has not previously been incriminated as an intermediate host. However, schistosome-infected B. nyassanus were discovered in surveys to identify transmission sites on the peninsula. Experimental infections of wild-caught B. nyassanus with S. haematobium proved successful and S. haematobium eggs were found in hamsters experimentally exposed to cercariae retrieved from schistosome-infected, field-collected B. nyassanus. These are remarkable observations since, although there are very few reports of diploid members of this species group being experimentally infected with S. haematobium, B. nyassanus is a diploid member (2n = 36) of the truncatus/tropicus group. Bulinus nyassanus is probably responsible for transmission in Lake Malawi, along rather exposed shorelines, devoid of aquatic macrophytes, with a substrate of sand or gravel.     

Efficacy of praziquantel against Schistosoma haematobium infection in children

A study was performed to determine the efficacy of praziquantel (PZQ) against Schistosoma haematobium. Children (n = 592) infected with S. haematobium received either a single treatment with PZQ (40 mg/kg) or two or three treatments with PZQ at three-week intervals after the initial treatment and efficacy was monitored for nine weeks. Cure rates at three-weeks post-treatment were low (< 50%), suggesting either that worms are killed very slowly or, more likely, that eggs continue to be released from tissues after worm death. Interestingly, a single dose of PZQ showed high efficacy (cure rate > 83% and egg reduction rate > 98%) when assessed from six weeks post-treatment onward. There were no significant differences in cure rates or intensity of infection between the three cohorts at any point in the study, despite the different treatment regimens. Since children were in contact with transmission sites during the study period, the results suggest good efficacy of PZQ against all stages of S. haematobium, including the immature worms.     

Ultrasonographic changes of the liver in Schistosoma haematobium infection.

Abdominal ultrasonographic examination was performed in 61 hospitalized patients with chronic liver diseases and 253 school children from a village endemic for Schistosoma haematobium and were compared with 142 urban children without exposure to Schistosoma. The prevalence of ultrasound-detectable hepatomegaly and splenomegaly and the degree of periportal fibrosis was compared between those with and without S. haematobium infection. Among 13 patients with biopsy-proven schistosomal hepatic fibrosis, three with coarse changes secondary to S. mansoni infection showed grade III periportal fibrosis, while 10 patients with fine schistosomal hepatic fibrosis due to S. haematobium had borderline (two) or grade I (eight) changes. Ultrasound evidence of periportal fibrosis was not detected in patients with hepatic cirrhosis, chronic active hepatitis, or fatty infiltration. However, three of 14 patients with chronic persistent hepatitis had grade I periportal fibrosis and two had borderline changes. The frequency of ultrasound-detected hepatomegaly and splenomegaly was greater among rural S. haematobium-infected children (35.2% and 22.4%, respectively) than among noninfected rural (21.1% and 13.3%) and urban (16.9% and 4.9%) children. Also, the frequency of grade I periportal fibrosis was significantly greater (P less than 0.01) in S. haematobium-infected children (22.4%) than in noninfected rural (11.7%) and urban (0.7%) children. No patients with S. haematobium infections, either in the hospital or the village, had grade II or III periportal fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Predisposition to urinary tract epithelial metaplasia in Schistosoma haematobium infection

Although there is strong epidemiologic evidence linking Schistosoma haematobium infection with carcinoma of the bladder, the utility of cytologic screening for urinary tract cancer has not been critically evaluated in S. haematobium-endemic populations. The present cross-sectional study examined urine cytology findings among 1,014 residents (ages 1 to 91) of the S. haematobium-endemic Msambweni area of Coast Province, Kenya. Among 705 evaluable cytology specimens, prevalence of inflammation (39%), hyperkeratosis (30%), metaplasia (33%), and frank atypia (0.4%) was notably higher than in previously studied, non-endemic populations. Overall, S. haematobium infection was strongly associated with increased risk for cytologic abnormality (> 2.8-fold relative risk of metaplasia or hyperkeratosis; P < 0.001). Age-group analysis confirmed parallel increases in metaplasia and S. haematobium infection prevalence early in life (from age I to 15 for both boys and girls). However, above age 20, metaplasia prevalence persisted at 33-45% prevalence despite a decline in infection prevalence and intensity. Prevalence of advanced (moderate or severe) metaplasia showed two age-related peaks: the first at 10-14 years of age (at the time of peak infection), and the second among subjects > or = 60 years old. No cancers were detected in the study population either on cytology or on follow-up ultrasound examination. These data suggest an age-dependent progression of cellular abnormalities in the urinary epithelium that is associated with chronic S. haematobium infection, which becomes independent of concurrent infection intensity as subjects grow older. Implications for cancer screening are discussed.     

Studies on experimental mixed infection of Schistosoma haematobium and Schistosoma mansoni in the albino mouse

Swiss albino mice have been infected with S. haematobium and challenged with S. mansoni. No apparent disturbances as regards worm load and oviposition were observed. Yet certain deviations in the egg-distribution sites for both species were found. They were attributed to the possibility of earlier de-development of collateral circulation. Cross-pairing between the two species was met with, which might explain the extra number of S. haematobium eggs found in the small intestine. Although no major effect has been revealed, no conclusion at this stage could be put forward as regards complete absence of cross-immunity.     

Leukocyte adherence to Schistosoma haematobium eggs from children

The pattern of leukocyte adherence to voided Schistosoma haematobium eggs was compared in children 7-16 years old. A method enabling the measurement of the intensity of adherence was first developed by means of scanning electron microscopy, after which it was adapted for light microscopy. The intensity of adherence decreased from younger to older age groups. This result was unexpected, and has bearing on contemporary views on immunity to human schistosomiasis, particularly the blocking antibody theory.     

Simple clinical manifestations of genital Schistosoma haematobium infection in rural Zimbabwean women

Up to 75% of women with urinary schistosomiasis have Schistosoma haematobium ova in the genitals. This study aimed to describe the prevalence of gynecologic S. haematobium infection and to differentiate the disease from sexually transmitted infections (STIs). Gynecologic and laboratory investigations for S. haematobium and STIs were performed in 527 women between the ages of 20 and 49 in rural Zimbabwe. Genital homogenous yellow and/or grainy sandy patches, the commonest type of genital pathology, were identified in 243 (46%) women. Grainy sandy patches were significantly associated with S. haematobium ova only. Genital S. haematobium ova was also significantly associated with homogenous yellow sandy patches, mucosal bleeding, and abnormal blood vessels. The presence of ova was not a predictor for ulcers, papillomata, leukoplakia, polyps, or cell atypia. Mucosal sandy patches seem to be pathognomonic for S. haematobium infection in the female genitals. Coexistence of ova and other lesions may not be causal.     

Granuloma size in the liver of mice with Schistosoma haematobium infection and Schistosoma mansoni challenge.

Swiss albino mice have been infected with S. haematobium and challenged with S. mansoni. S. haematobium infection in the mouse runs a course more or less parallel to that of S. mansoni infection. Granuloma has reached a maximal size at 135 days post infection and has regressed thereafter. Suppression of S. mansoni granuloma was observed in mice previously infected with S. haematobium. This manifests the presence of cross immunization.