Toxoplasma gondii: virulence of tachyzoites in serum free media at different temperatures.

Highly virulent Toxoplasma gondii tachyzoite multiplication was recorded on the 4th and 5th days post cultivation (dpc) in seven selected cell lines either with or without fetal calf serum (FCS) in the maintenance media. The multiplication rate was slightly lower in the absence of FCS. The cell line mono-layers collapsed dying by the 6th day of infection both in presence or absence of FCS at 37 degrees C. Carcinoma of human larynx (Hep2) and Madian Darby Bovine Kidney (MDBK) cell lines were the most suitable for in vitro multiplication, followed by that of African green monkey kidney cells (VERO), pooled kidney from 1-day-old hamster (BHK), rabbit kidney cells (RK13) and human rhabdomyosarcoma (RDA), while Chicken embryo cells (CER) were the least suitable. In absence of FCS, CER, BHK, Hep2, RDA and MDBK were able to maintain virulent tachyzoites at +4 degrees C for 14 days. The infectivity of the tachyzoites was however lower, killing 40% of the inoculated mice. Tachyzoites survived at room temperature, in the dark, for 14 days in Hep2, RDA and MDBK. However, Hep2 was the only one able to keep virulent tachyzoites until 21 dpc at room temperature and at +4 degrees C. Hep2 propagated tachyzoites were still alive but with low infectivity up to 28 dpc. The cell-lines failed to support the development of tachyzoites after 7 dpc at 37 degrees C and after the 35 dpc at lower temperatures.

Value of Haemonchus longistipes purified antigens in diagnosis of gastro-intestinal nematodes infection in camels.

Fractionated Haemonchus longistipes crude antigen revealed 7 protein fractions at molecular weights of 93, 74, 67, 56, 32, 26 and 16 kDa. The bands at 56, 32 and 26 kDa reacted specifically with H. longistipes hyperimmune sera prepared in rabbit (1:100 dilution) using EITB technique. The eluted concentrated fractions as well as crude worm antigens were used in diagnosis of natural infection of Gastro-Intestinal Nematodes (GIN) only or associated with other parasites in camels using ELISA technique. H. longistipes crude antigen and fraction of 26 kDa induced high sensitivity in diagnosis of infection in animals harboring GIN only (sensitivity was 95-100%), while it was 85.0-93.3% with 32 kDa fraction and 55.5-73.3% with that of 56 kDa using ELISA technique. The two H. longistipes eluted protein fractions of 26 and 32 kDa showed higher sensitivity than their crude antigens in diagnosis of GIN infection mixed with other parasites. While, Protein bands of 26 kDa appeared more sensitive than the other protein bands in detection of anti- H. longistipes antibodies at higher serum dilution. With special superiority for fraction of 26 kDa, in comparison with the other antigens, sharp specificity or sensitivity in diagnosis, could not be achieved in this study especially in case of mixed infection with other parasites, where these animals might be immune-compromised.

Anticoccidial efficacy of drinking water soluble diclazuril on experimental and field coccidiosis in broiler chickens.

Prophylactic and curative capacity of water soluble formulation of Diclazuril (Diclosol 1%) and feed additive form (Clinacox, 0.5%) were tested against Eimeria infection in broiler chickens. Such testing was performed both experimentally and in the field. Toltrazuril (Baycox, 2.5%) was used as reference control drug. Water soluble formulation of Diclazuril induced a marked inhibitory effect on the different stages of the parasite life cycle in experimentally infected treated birds especially when applied on the day when blood first appeared in the faeces [fifth day post-infection (d.p.i.)] as well as on the second day of blood dropping (6 d.p.i.). Both tested dosage levels of Diclazuril water soluble formulation in drinking water (5 and 10 ppm) showed the same effect in controlling coccidial infection and reducing the total oocyst numbers, lesion and faecal scores. Moreover, there was no significant difference in the efficacy of water soluble form of Diclazuril and the reference control drug (Toltrazuril, 25 ppm). In addition, testing the water soluble formulation (5 ppm) in naturally infected poultry farm (20,000 birds), showed the same anticoccidial effect observed when using Toltrazuril, as a treatment for coccidiosis. In conclusion, addition of Diclazuril at the dose of 5 ppm in the drinking water of naturally coccidia infected bird induced the same effect as 25 ppm of Toltrazuril as a treatment for coccidiosis in chickens.

A global network for the control of snail-borne disease using satellite surveillance and geographic information systems.

At a team residency sponsored by the Rockefeller Foundation in Bellagio, Italy, 10-14 April 2000 an organizational plan was conceived to create a global network of collaborating health workers and earth scientists dedicated to the development of computer-based models that can be used for improved control programs for schistosomiasis and other snail-borne diseases of medical and veterinary importance. The models will be assembled using GIS methods, global climate model data, sensor data from earth observing satellites, disease prevalence data, the distribution and abundance of snail hosts, and digital maps of key environmental factors that affect development and propagation of snail-borne disease agents. A work plan was developed for research collaboration and data sharing, recruitment of new contributing researchers, and means of access of other medical scientists and national control program managers to GIS models that may be used for more effective control of snail-borne disease. Agreement was reached on the use of compatible GIS formats, software, methods and data resources, including the definition of a 'minimum medical database' to enable seamless incorporation of results from each regional GIS project into a global model. The collaboration plan calls for linking a 'central resource group' at the World Health Organization, the Food and Agriculture Organization, Louisiana State University and the Danish Bilharziasis Laboratory with regional GIS networks to be initiated in Eastern Africa, Southern Africa, West Africa, Latin America and Southern Asia. An Internet site, www.gnosisGIS.org, (GIS Network On Snail-borne Infections with special reference to Schistosomiasis), has been initiated to allow interaction of team members as a 'virtual research group'. When completed, the site will point users to a toolbox of common resources resident on computers at member organizations, provide assistance on routine use of GIS health maps in selected national disease control programs and provide a forum for development of GIS models to predict the health impacts of water development projects and climate variation.

Geographic information systems as a tool for control program management for schistosomiasis in Egypt.

During a 4-year study a geographic information system (GIS) risk model was constructed for predicting the relative risk of schistosomiasis in Kafr El-Sheikh governorate, Egypt. A 1-year 1990-1991 time series on diurnal temperature difference (dT) prepared from the advanced very high resolution radiometer (AVHRR) sensor on the NOAA-11 satellite was used to develop a regional risk model for the Nile delta based on thermal-hydrological domains. A May 15, 1990 Landsat TM scene (path 177, Row 38) was used to develop a local 'village-scale' environmental risk model based on higher resolution satellite sensor data (30 m picture element size at earth surface). Four of ten classes derived from a tasseled cap (Tcap) transformation of the Landsat TM scene were shown to be significantly related to a 5-year Schistosoma mansoni prevalence database from the Ministry of Health. A risk model was developed based on dT and the proportional area of the four Tcap classes in 5 km(2) buffer zones centered on rural health unit (RHU) reporting units. Available historical data on S. mansoni and its snail host Biomphalaria alexandrina, as well as recent field collected data were gathered and incorporated as separate themes. Model validation was done using data collected on snail population bionomics-infection rates, water quality, underground water table and cercariometry at 13 hydrologically representative sites. The role of soil type, water table and water quality was studied at 79 of 154 rural health unit sites. The model permitted retrieval of relevant data by RHU point location. For the first time in Egypt, the Kafr El-Sheikh GIS schistosoma prediction model can support MOH efforts to make more accurate control program decisions based on environmental predilection sites of endemic Schistosomiasis mansoni.

Development and validation of a satellites based geographic information system (GIS) model for epidemiology of Schistosoma risk assessment on snail level in Kafr El-Sheikh Governorate.

The aim of the present study was to test the accuracy of Advanced Very High Resolution Radiometer (AVHRR) satellite derived temperature difference (dT) maps as a guide for the suitability of the environment for local snail hosts and Schistosoma development-transmission at the village level. The study provided field validation data from 13 villages in Kafr El Sheikh in the Nile Delta that sites present in wet zones of low dT value have more abundant snail populations than that present in the drier zones with high dT values. Results suggest that lower dT values were associated with wetter hydrologic regimes related to the level of underground water table and that this is reflected in the abundance of snail populations and Schistosoma snail infection rates at the village level. Water quality parameters on pH salinity and dissolved oxygen were not correlated with presence of Schistosoma infected snails. Results indicate that abundance of snails and S. mansoni prevalence are related to thermal-hydrology domains associated with surface water, that habitat suitability is related to depth to water table and that regional hydrology characteristics that affect snail host habitat suitability (ie. wet, moist, dry or very dry) can be evaluated using AVHRR dT maps.

Anticoccidial efficacy of toltrazuril and halofuginone against Eimeria tenella infection in broiler chickens in Egypt.

The anticoccidial activities of toltrazuril and halofuginone against Eimeria tenella were tested in broiler chickens. Comparisons were made between ummedicated infected and uninfected control birds in addition to infected groups given either toltrazuril at 37.5, 75 and 150 ppm in the drinking water, or halofuginone at 1.5, 3 and 6 ppm in the feed. Both drugs were highly efficacious against E tenella. Treatment improved the bodyweight gain and survival percentage in comparison with the unmedicated, infected group. Intestinal lesions, faecal and oocyst scores and oocyst shedding in dropping were significantly reduced by both drugs. Toltrazuril gave better protection than halofuginone; 75 and 150 ppm toltrazuril in drinking water gave good protection when administered four and five days after inoculation.

Geographic information systems and the distribution of Schistosoma mansoni in the Nile delta.

New computer-based sensor technology and geographic methods have led to emerging interest in use of satellite environmental assessment tools for design of disease control programs, especially for those that are vector borne. The long-range goal of work reported here by John Malone and colleagues on behalf of this Egyptian Ministry of Health-USAID Schistosomiasis Research Project team (Box 1) is to utilize data from sensor systems on board earth-observing satellites to develop more-sensitive disease-prediction and -control models. If successful, methods developed may provide a potentially vital capability for use by disease control program managers, particularly in less-developed countries, where mapping resources are not well advanced. Longer term, broader basic questions on the interaction of environment and disease in anticipation of predicted global climate change may be addressed. These studies focused on the lower Nile river basin of Egypt. The specific objective was to link data on environmental requirements for propagation and transmission of schistosomiasis with parameters measurable from space.

Perinatal mortality in an Egyptian maternity hospital.

The factors affecting perinatal mortality during a period of 21 months were studied at Al-Galaa Teaching Hospital, using the International Fertility Research Program's Maternity Record 903 to collect the data. There were 6990 deliveries during the 21 months and 580 hospital perinatal deaths. Certain high-risk factors associated with perinatal mortality were identified including both biosocial and biomedical factors. The biosocial factors affecting perinatal mortality in this study are discussed, including maternal education, marital status, residence, hospital status as paying or non-paying patient, maternal age, registration status, outcome of last pregnancy, parity/family size, antenatal care, maternal hemoglobin, and the weight and sex of the baby.

Pregnancy wastage.

PIP: This study of early and late pregnancy wastage performed at 3 Egyptian teaching hospitals to assess the magnitude of the problem, detect its causes and recommend measures that will eliminate such causes and reduce pregnancy wastage. As defined here, pregnancy wastage includes abortion and perinatal mortality. In Egypt early pregnancy wastage varies between 23.8%-36.57%, and late pregnancy wastage between 15.3%-88%. The results of these studies show that spontaneous abortion is high among low socio-economic class and high parity groups. The incidence of spontaneous abortion is found to vary with wife's education, husband's education, wife's age, age at marriage, parity and order of living children. The perinatal mortality rate (PNMR) showed variation with socioeconomic factors, biomedical factors, primary antenatal condition of expectant mothers and manpower training. Results indicate a high PNMR among mothers who were not booked at a hospital and only came to the hospital for the 1st time in labour, among those patients in labour who were referred to the hospital by traidtional birth attendants, as opposed to a general practitioner, and among non-paying patients. Moreover, the PNMR was high for non-educated mothers and for those who had never received any antenatal care. The highest PNMR was among those women who had received 8 or more antenatal visits as they represent the high risk patients. With respect to biomedical factors, the PNMR was found to vary with the maternal age groups, parity, outcome of the last pregnancy and gestational age. Additional contributing factors were pre-existing maternal diseases like anemia, toxemia of pregnancy, diabetes mellitus and antepartum hemorrhage. Finally, analysis of PNMR in this study shows that PNMR varies with the degree of skill of the birth attendant and his/her awareness of the problem of PNMR and the hospital's recording system. The analysis of perinatal mortality cases revealed that most of the underlying causes are preventable. The analysis also showed that 45% of the cases occured in the antepartum period, 30% in the intrapartum period and 25% in the postpartum period. The significant loss in the postpartum period is a strong reason for the obstetrician to work in close contact with the neonatologist to reduce the PNMR. The pregnancy wastage rate in Egypt and other developing countries can be markedly reduced by bettering socioeconomic standards, promoting the use of effective contraception, improving health services, health education obstetric practice, and manpower training, and by establishing neonatal units and a proper recording system.^ieng

A study of the biosocial factors affecting perinatal mortality in an Egyptian maternity hospital.

PIP: This article reports on a retrospective study of perinatal deaths in an Egyptian maternity hospital during a 21 month period from March 1977 to November 1978. 6990 babies were delivered in the hospital during the study period. A special precoded maternity record was filled in for each mother. It included detailed information on the social and medical aspects of the mother and the delivery. Another form was filled in for all the perinatal deaths and included a detailed description of possible causes of death together with results of post-mortem examinations when available. The perinatal mortality rates reported in this study are quite high, particularly among patients who start labor at home and come the the hospital when labor is prolonged or complicated. Moreover, 62% of these patients were non-literate and 71.2% had received no antenatal care. Among the various biosocial factors studied, maternal age and education are found to have the most impact on the prevalence of perinatal deaths. Incidence of perinatal mortality was nearly doubled in the cases referred by the Dayas (traditional birth attendants) when compared with booked cases; and 1 1/2 times that of cases referred by a physician. The availability of antenatal care and the hemoglobin % were found to affect perinatal mortality. A higher rate of perinatal mortality was found in women with previous still births, 2 or more spontaneous abortions, a perterm delivery or more than 3 deliveries. The study confirms the findings of other researchers that duration of pregnancy is an important factor in deciding perinatal outcome. Higher mortality rates occurred in preterm and post-term deliveries. In addition, duration of labor and type of delivery together with the time of rupture of membranes are found to affect perinatal outcomes.^ieng

[Level of SO2 pollution and the prevalence of bronchitis]. / Niveau de pollution par le SO2 et prévalence de la bronchite.

The prevalence of chronic bronchitis (according to the BMRC questionnaire on respiratory symptoms) for 1182 male smokers, as well as their peak flow rate, are related to age (18-65 years), cagarette consumption (1-55 cig./day) and exposure to atmospheric SO2 pollution (20-65 microgram/m3).

[The importance of bacterial exposure in sanitation employees when collecting refuse]. / Importance de l'exposition bactérienne chez les employés de la voirie chargés de la levée des ordures

During their Work, Dustmen are exposed to important and various microbiological Aerosols, which, according to the Granulometry, could have an Influence on the Start and the Progress of chronic Bronchitis.

[Chronic bronchitis and risk factors in employees of the sanitation départment, city of Geneva]. / Bronchite chronique et facteurs de risque chez les employés de la voirie à Genève

The MRC questionnaire on respiratory symptoms was applied to 429 employees of the sanitation department of the city of Geneva. At the same time, the PFR was determined. The prevalence of the chronic bronchitis was shown to be three times as high in this sample as in the active population of Geneva from the same age group. According to our results, the severity of the respiratory symptoms as well as the level of the respiratory function depended, besides age, on the three risk factors which had been taken into account: cigarette smoking, a history of broncho-pulmonary disease and occupational exposure to weather conditions and air pollution. In the absence of these factors, the severity of symptoms was the lowest and the respiratory function the highest. With all these factors combined, the severity of symptoms was the most pronounced and the function the worst, particularly in bronchitics. It seems that prevention of chronic bronchitis should not rely only upon antismoking propaganda but that the combination of several risks factors should be avoided.