The epidemiology of schistosomiasis in Egypt: patterns of Schistosoma mansoni infection and morbidity in Kafer El-Sheikh.

This is a descriptive report of the Epidemiology 1, 2, 3 project in Egypt that made use of large probability sampling methods. These results focus on Schistosoma mansoni infection in the northern Nile Delta governorate of Kafr El Sheikh. A probability sample of 18,777 persons, representing the rural population of the entire governorate, was drawn. The sample was designed not to exclude villages based on location or presence of health care facilities and to include representation of the smaller ezbas or hamlets. The objective was to obtain detailed estimates on age- and sex-specific patterns of S. mansoni infection, and to provide a baseline for prospective studies. Stool specimens were examined by the Kato method. The estimated mean +/- SE prevalence of S. mansoni infection in the rural population was 39.3 +/- 3.3% in 44 villages and ezbas after weighing for the effects of the sample design. The estimated mean +/- SE geometric mean egg count per gram of stool (GMEC) was 72.9 +/- 7.3. Prevalence and GMEC varied considerably by village and ezba, with ezbas having a significantly higher prevalence. Villages and ezba-specific prevalence was strongly associated with GMEC (r2 = 0.61, P < 0.001). The prevalence of S. mansoni infection increased by age to 55.4 +/- 3.2% at age 16 without a significant change in the adult ages. There were no gender differences until age 6, after which males were consistently higher until middle age, when the differences converged. The age- and sex-specific pattern of GMEC varied widely; however, when the GMEC data were collapsed into 5-year age groups, the GMEC peaked at 81.5 +/- 12.1 eggs/g in the 10-14-year-old age group. These estimates provide the basis for evaluating control measures for reducing prevalence, intensity of infection, and transmission.

Study on rodents infestation in Alexandria and prevalence of Trichinella spiralis infection among them.

Rodents were monthly collected from the six districts of Alexandria all year round using live traps. The 1025 collected rodents were divided according to species, gender, age, and weight El-Amryia and El-Montaza were the most infested districts, while West, East, Middle and El-Gomrok Districts were the lowest infested ones. Rallus norvegicus was the highest abundant species in the city (41.9%) followed by R. rattus (37.2%), then Mus musculus (20.9%). There was no difference in abundance of rodents during summer compared with winter. Meanwhile, males represented 57.6% of the total collected rodents. Most of the collected rodents were < or = 2 months old (63.8%) or light weighed (61.6%) however, number of caught rodents became less and less as age or weight increased. Concerning El-Amryia and El-Montaza Districts where abattoirs are located, number of collected rodents from and around the abattoirs represented 70.4% of the total collected rodents compared with 29.6% collected from and around the houses of the same districts. The total prevalence of T. spiralis infection among collected rodents using digestion technique was 13.3%. El-Amryia, El-Montaza, West and El-Gomrok Districts were, in order, the only infected districts. Neither gender nor season of collection has influence on the prevalence of infection. The present study proved the role of abattoirs in the prevalence of T. spiralis infection. However, high prevalence of T. spiralis infection was detected among higher age or higher body weight groups of rodents. Sensitivity of the digestion diagnostic technique is proved compared with compressorium diagnostic technique. Nevertheless, diaphragm was the most sensitive site for detection of light infection in all studied rodents followed by thigh then tongue; expressed as number of larvae per gram tissue.

Schistosoma mansoni in the Nile Delta, Egypt. A large scale epidemiological study in Kafr El Sheikh Governorate.

This is an early descriptive report of the 'Epidemiology 123' project in Egypt which makes use of large probability sampling methods. These results focus on Schistosoma mansoni infection in the northern Nile Delta Governorate of Kafr El Sheikh. A probability sample of 18,777 persons, representing the rural population of the entire Governorate, was drawn. The sample was designed not to exclude villages based on location or presence of health care facilities and to include representation of the smaller ezbas or hamlets. The objective was to obtain detailed estimates on age and sex specific patterns of S. mansoni infection, and to provide a baseline for prospective studies. Stool specimens were examined by the Kato method. The estimated prevalence of S. monsoni infection in the rural population was 39.3% (SE +/- 3.3) in 44 villages and ezbas after weighing for the effects of the sample design. The estimated geometric mean egg count per gram stool (GMEC) was 72.9 (SE +/- 7.3). Prevalence and GMEC varied considerably by village and ezba, with ezbas having a significantly higher prevalence. Villages and ezba specific prevalence was strongly associated with GMEC (r2 = 0.61, p < 0.001). The prevalence of S. mansoni infection increased by age to 55.4% (SE +/- 3.2) at age 16, without significant change in the adult ages. There was no gender difference until age six, after which males were consistently higher until middle age, when the differences converged. The age and sex specific pattern of GMEC varied widely, however, when the GMEC data were collapsed into five year age groups, GMEC peaked at 81.5 (SE / + - 12.1) epg in the 10 to 14 year age group. These estimates provide the basis for evaluating control measures for reducing prevalence, intensity of infection, and transmission.

Impact of population-based selective chemotherapy on prevalence and intensity of Schistosoma mansoni infections in the Nile Delta: Kafr El Sheikh.

The impact of selective treatment with praziquantel (40 mg/kg) on Schistosoma mansoni prevalence and intensity of infection in two annual follow-up examinations was measured. The target population was the entire rural area of the northern Nile Delta Governorate, Kafr El Sheikh, from which a probability sample was drawn. The sample included 44 villages and hamlets (ezba). Baseline prevalence was determined by the examination of stool by two Kato slides and all infected persons treated and reexamined one year later. Those found infected in the second round were treated and examined again one year later. The prevalence and geometric mean egg count declined across all ages in each follow-up (prevalence: 39.3% (SE +/- 3.3), 28.4% (SE +/- 2.6), and 22.4% (SE +/- 2.3), respectively; and GMEC: 72.9 (SE +/- 7.3), 52.5 (SE +/- 4.5), and 41.9 (SE +/- 2.4), respectively). Reduction in prevalence varied considerably by village and ezba and was strongly related to the proportion of the village or ezba population that was infected and treated (r2 = 0.29). This latter observation provides a rationale for the maximum application of chemotherapy in the endemic Nile Delta community.

The epidemiology of Schistosoma mansoni, hepatitis B and hepatitis C infection in Egypt.

There appears to be no epidemiological association between Schistosoma mansoni infection, the intensity of S. mansoni infection or S. mansoni infection complicated by schistosome hepatic fibrosis and the presence of antibody to hepatitis B virus core antigen (anti-HBc), hepatitis B surface antigen (HBsAg), antibody to hepatitis C virus (anti-HCV) or antibody to both agents. This was the main conclusion of a population-based study of an entire village in the northern Egyptian Nile Delta. All 1850 villagers were invited to participate and serological, parasitological and ultrasound examinations were completed on a high proportion of the total population (68% provided sera and higher percentages provided stool specimens and were subjected to ultrasound examinations). Testing with dual Kato slides indicated a high prevalence of S. mansoni infection in the village (49.1%), typical of the area. Hepatitis B virus (HBV) markers (presence of either anti-HBc and/or HBsAg) and anti-HCV were also found to be prevalent, present in 24% and 15.9% of the villagers, respectively. The age-adjusted odds ratios (OR) for infection with S. mansoni and HBV [1.13; 95% confidence interval (CI) = 0.87-1.48], HBsAg (1.11; CI = 0.47-2.58), or anti-HCV (1.02; CI = 0.7-1.37) were not significantly greater than unity. Similarly low and non-significant OR estimates were observed with those positive for both HBV and anti-HCV. No other outcome measures of S. mansoni infection (i.e. intensity of infection or ultrasonographically-determined schistosomal hepatic fibrosis) were found to be associated with HBV, HBsAg or anti-HCV.(ABSTRACT TRUNCATED AT 250 WORDS)