The epidemiology of schistosomiasis in Egypt: Assiut governorate.

In the Assiut, Egypt Epidemiology 1, 2, 3 investigation, a sample of 14,204 persons in 10 villages, 31 ezbas (satellite communities), and 2,286 households was drawn from a rural population of 1,598,607. Parasitologic examination of urine and stool were made for Schistosoma haematobium and S. mansoni, and physical and ultrasound examinations were made on a 20% subsample. The overall estimated prevalence of S. haematobium was 5.2 +/- 0.5 (+/- SE). This varied considerably by village and ezba, ranging from 1.5% to 20.9%, with ezbas having a slightly higher overall prevalence than villages. The overall estimated geometric mean egg count was 6.6 +/- 0.5 eggs per 10 ml of urine and was consistently low throughout the communities. Infection with S. haematobium was associated with age (peak prevalence of 10.6 +/- 1.5% in 15-19-year-old age group) males, children playing in the canals, a history of blood in the urine, and reagent strip positivity for hematuria and proteinuria. The prevalence of either hepatomegaly or splenomegaly detected by physical examination was low (4.0% and 1.5%, respectively). The prevalence of hepatomegaly determined by ultrasonography was substantially higher, 24.1%. The prevalence of periportal fibrosis (PPF) was 12.0%, but grade II or III PPF was present in less than 1%. Ultrasonography-determined hepatomegaly, in both the midclavicular line and the midsternal line, increased by age to more than 30%. Periportal fibrosis was more common in the age groups in which infection rates were the highest. At the village and ezba level of analysis, the prevalence of hepatomegaly, splenomegaly, and PPF tended to be higher in communities having the highest prevalence of infection with S. haematobium.

Relationship between pure Schistosoma haematobium infection in Upper Egypt and irrigation systems. Part 1: methods of study.

Four villages in Assiut Governorate were studied. They were matched for availability and time of introduction of medical services, the size of population and the socioeconomic status. One village had a basin system of irrigation. The other three villages had perennial irrigation introduced at different dates. A sketch map of each village was made showing the location of every house and the irrigation channels. Total coverage was intended in Gezirat El-Maabda (with basin irrigation) and Nazza Karar (with perennial irrigation-recently introduced). In El-Ghorayeb and Garf Sarhan (with older systems of perennial irrigation) systematic random samples were studied. The Study included a full, double check clinical examination of urine and stools samples and a social study. Data about educational level and activities that bring the individual in contact with canal water were recorded. Tables showing the age and sex distribution of the total population and the population studied in each village are presented and show validity of the samples taken from the population.

Relationship between pure Schistosoma haematobium infection in Upper Egypt and irrigation systems. Part II: Host characteristics. The general prevalence of Schistosoma haematobium, age and sex distribution.

The epidemiology of bilharziasis was studied in four villages in Assiut Governorate. These villages were almost similar with respect to their socioeconomic conditions, modes of living, availability and date of introduction of medical services. The first village, Gezirat El-Maabda, has a basin system of irrigation. The other three villages had shifted to the perennial system of irrigation for three years in Nazza Karrar, 26 years in El-Ghorayeb and 95 years in Garf Sarhan and were similar with respect to proximity to water courses. So the only variable of importance between the four villages was the mode of irrigation. Bilharziasis was diagnosed by detection of eggs in urine or faeces. A definitive relationship between the prevalence of S. haematobium infection and the type of irrigation system was further documented. A low prevalence was found in Gezirat El-Maabda (2.95%). In the other three villages a much higher prevalence existed (31.9%, 46.2% & 38.9% in Nazza Karar, El-Ghorayeb and Garf Sarhan respectively). The higher prevalence of S. haematobium in Nazza Karar (31.9%) only three years after introduction of perennial irrigation was a disappointing finding. It can be considered as an evidence against the elaborate measures and precautions planned and incompletely implemented before or after the establishment of Aswan High Dam. Not a single case of S. mansoni was encountered during this study. As regards the age and sex distribution of S. haematobium in the three villages irrigated perennially, a steep rise started at the age group 5-9 years reaching a peak at the age group 10-14 years. In Gezirat El-Maabda the peak was reached at later age (15-19 years). The cause of this difference was explained. Males showed a higher rate of infection than females in almost all age groups of the four village studied.

Relationship between pure schistosoma haematobium infection in Upper Egypt and irrigation systems. Part III: Host characteristics. The prevalence of S. haematobium in relation to religon, occupation, and habits.

Study of the effect of religion on the prevalence of S. haematobium infection revealed that ablution and other Muslims rituals do not represent an important factor in the prevalence of S. haematobium. Data concerning the effect of education on the prevalence of S. haematobium show that it has no significant role when similar age groups were compared. Farming was shown to be the occupation of leading importance with rest to exposure to S. haematobium infection, as farmers and farm labourer constitute a large sector of our rural population. Finishing, although forming a greater danger in this respect, is not a common occupation in the studied villages with the exception of El-Ghorayeb. The study showed that swimming in canal water is one of the most important activities causing infection with bilharziasis.

Study of the pattern of Widal test in infants and children; II. Pattern of Widal test in children with enteric fevers. An attempt to define the diagnostic titer for upper Egypt.

The study embodied 45 children with enteric fevers proved by bacteriological culture of blood, stools and urine and 20 children with rheumatic fever. Widal test was done for the rheumatic fever cases and was done repeatedly at weekly intervals for the enteric fever cases. The clinical features of children with enteric fevers was discussed. By contrasting the results of Widal test in children with enteric fever with the results in apparently normal infants and children from the same locality, a minimal diagnostic dual Widal titer was suggested. This combines "O" agglutinin in a titer of 1/160 provided that the other "H" agglutinins are at a lower titer. This suggested diagnostic titer improved the specificity of Widal test. This titer is encountered only in 0.58% of normal individuals and in none of 20 children with rheumatic fever. This titer also yielded an excellent sensitivity to diagnose actual enteric fever cases reaching up to 93.3%. Bacterial isolates from enteric fever cases were S. typhi in 55.5%, S. paratyphi A in 33.3% and S. paratyphi B in 11.1%. Chloramphenicol therapy resulted in a higher cure rate and a more rapid defervescence than ampicillin therapy. Regarding the effect of these antibiotic therapies on the rise of Widal agglutinin titers in children with enteric fevers there are two observations : 1--A four fold rise, is uncommon. A two fold rise is the common finding. 2--There is no consistent difference between chloramphenicol and ampicillin as regards their effect on the rise of agglutinin titers.