Anaemia and Schistosoma haematobium infection in the North-Eastern Province of Kenya

The haemoglobin levels of 787 Somali people in north-eastern Kenya were measured. Severe anaemia was very common in both sexes of all ages. Possible causative factors are discussed. Adolescent boys had particularly low haemoglobin values (in one area 43% had levels below 8 g/dl) and this was related to Schistosoma haematobium infection. Such a clear relationshiop has not been shown before.     

Large scale irrigation and arbovirus epidemiology, Kano Plain, Kenya. II. Preliminary serological survey

1,844 of 4,109 sera collected from children in 26 schools on the Kano Plain, Nyanzo Province, Kenya during May and June 1969 were tested for antibodies to a variety of arboviruses. Over 60% of the children had HI antibodies against both Chikungunya and O'nyong-nyong viruses and 45% had antibody levels of 1 : 160 or greater against O'nyong-nyong suggesting recent infection with this virus. 35% of children aged less than 6 years had O'nyong-nyong virus antibodies and O'nyong-nyong was probably the virus responsible for most of the group A virus antibody. The average annual probability of infection with O'nyong-nyong virus was calculated at 9·6% and the virus is probably endemic in the area.Very few sera were found with group B virus antibodies but West Nile and probably Zika virus is thought to be endemic at a low level. Bunyarnwera group viruses are active in the area and Bwamba virus also appears to be endemic. Nyando virus antibodies were found in a considerable number of children aged 10 years or older and an epidemic probably occurred some 10–15 years previously; but there is no evidence that transmission is active at present.     

Arbovirus isolations from mosquitoes: Kano Plain, Kenya.

Arbovirus isolation attempts on 324,486 mosquitoes captured over a four-year period on the Kano Plain, Kenya, yielded 15 isolates including Pongola (six strains), Ilesha (three strains), Germiston (two strains), Sindbis (one strain), Barur (one strain) and two viruses which could not be characterized. Mansonia uniformis, Anopheles gambiae and Culex antennatus constituted 70% of the total collection and accounted for all of the isolates except one, which came from Anopheles funestus.     

The association between Schistosoma haematobium infection and heavy proteinuria

The prevalence of proteinuria was very much higher in 2 Egyptian villages infected with S. haematobium than in one that was not, though otherwise socially and economically very similar. In many inhabitants the proteinuria was heavy, suggesting nephritis rather than urological abnormality or pyelonephritis. Patients presenting with the nephrotic syndrome have a significantly higher incidence of schistosomiasis than matched controls. These studies support the view that schistosomiasis is a cause of nephritis.     

Egg output stability and the epidemiology of Schistosoma haematobium. II. An analysis of the epidemiology of endemic S. haematobium

On the basis of observations of school children described in Part I, a model for the infective process of S. haematobium in man in the Misungwi area of Tanzania is put forward. On the basis of steady challenge by cercariae, effective concomitant immunity, exponential death of worm pairs, the observed variance of egg output at age 10, and constant ranking by infection level in early life, the behaviour of egg output patterns with age in the community is predicted. Expected curves of output are compared with those observed in cross-sectional survey of over 4,000 people at Misungwi. Agreement is close. This provides additional evidence for the occurrence of concomitant immunity to S. haematobium in man and suggests that immunity cannot be disregarded in epidemiological models of the infection. It is suggested that there are 3 phases in an age-cohort's experience of endemic infection: acquisition and increase of infection, a phase of decreasing worm load combined with concomitant immunity, and a steady state phase, with loss of immunity and reinfection balancing, in later life. The need for better data on the nature of human immunity to schistosomiasis becomes apparent.     

The significance of proteinuria and haematuria in Schistosoma haematobium infection.

The intensity and prevalence of proteinuria and haematuria were studied with urinanalysis reagent strips in a Gambian community in which the intensity of infection with Schistosoma haematobium was high. The level of proteinuria present was shown to be related to the intensity of infection. Follow-up for 12 months showed that infected subjects with heavy proteinuria had a good prognosis. These findings suggest that the urinary protein in such subjects is likely to originate from lesions in the bladder and ureters and that advanced glomerular pathology is probably rare. The relationship of the levels of proteinuria and haematuria to the egg count suggests they may be parameters which could have value as indications for chemotherapy. Detailed study showed that the effect of treating all the subjects who had both 30 mg/100 ml or more of protein and at least a trace of haematuria would have been very similar to treating all those with an egg count of 200 ova/10 ml or more. Since urinalysis with reagent strips is very simple and rapid it could have a role in mass chemotherapy campaigns, particularly those aimed at the identification and treatment of heavily infected subjects.     

Evidence against rapid emergence of praziquantel resistance in Schistosoma haematobium, Kenya

We examined the long-term efficacy of praziquantel against Schistosoma haematobium, the causative agent of urinary schistosomiasis, during a school-based treatment program in the Msambweni area of Coast Province, Kenya, where the disease is highly endemic. Our results, derived from treating 4,031 of 7,641 children from 1984 to 1993, indicate substantial year-to- year variation in drug efficacy. However, the pattern of this variation was not consistent with primary or progressive emergence of praziquantel resistance. Mathematical modeling indicated that, at current treatment rates, praziquantel resistance will likely take 10 or more years to emerge.     

Arbovirus isolations from ixodid ticks infesting livestock,Kano Plain,Kenya

In a study conducted on the Kano Plain, Kenya, virus isolation attempts were made on ixodid ticks collected, over a 14-month period, from livestock held in family enclosures (bornas) before releasing the animals for daily foraging. 8735 Amblyomma variegatum (Fabricius) were tested, 98·6% of which were taken from cattle, yielding 36 strains of Dugbe (DUG), four strains of Nairobi sheep disease (NSD), three strains of Bhanja (BHA), one strain of Thogoto (THO) and five strains of virus which could not be characterized. 6549 Rhipicephalus spp. ticks were collected (60·3% from cattle). NSD, DUG and BHA viruses were each isolated twice from ticks taken from cattle. One BHA virus strain was recovered from ticks from a sheep. One strain recovered from ticks on cattle could not be characterized.     

Imported Schistosoma haematobium infection: report of 9 cases

BACKGROUND: Schistosomia haematobium infection has been eradicated from Tunisia since 1980. Only some imported cases are noted each year. AIM: The authors report nine cases of Schistosomia haematobium infection diagnosed. METHODS: The diagnosis was carried out within the framework of a survey carried out by the service of Pediatry of the hospital Mongi Slim of Tunis concerning 20 students of African extraction. RESULTS: Hematuria was found in all cases. Schistosomia haematobium infection is diagnosed in all patients by urinary parasitologic examination. Radiological evaluation had revealed mild uroradiologic abnormalities in five patients. All patients were treated by praziquantel. Remission was confirmed by urinary sterilization. Radiologic abnormilities persisted in 3 patients. CONCLUSION: Radiological evaluation and regular follow-up after treatment of students with Schistosomia haematobium infection is required.     

Water-contact patterns in relation to Schistosoma haematobium infection.

Water-contact observations were carried out on a population exposed to Schistosoma haematobium in a village situated on a man-made lake, Lake Volta, Ghana.