Serum copper and haematological values of sheep of different physiological stages in the dry and wet seasons of central trinidad.

A study was conducted to determine serum copper (Cu) concentrations and hematological values of 174 sheep from four medium sized farms, pertaining to physiological stage, in the late dry and late wet seasons of Central Trinidad. Serum Cu was significantly lower in the dry than in the wet season (P < 0.001) with a corresponding high percentage of samples with low Cu levels in the former. 31% of dry nonpregnant sheep exhibited a nonregenerative anaemia. Also, hemoglobin and packed cell volume values varied (P < 0.001) including lymphocyte (P < 0.01) counts, among growing animals compared with other physiological stages. Significant variations also occurred among neutrophil (P < 0.05) and eosinophil (P < 0.05) values in sheep. Highest haemoglobin and packed cell volume, white blood cell counts, and lymphocyte values in growing sheep compared with other stages were probably age related.

Sentinel surveillance for patients with acute hepatitis in Egypt, 2001-04.

Viral hepatitis is a major problem in Egypt. To define the epidemiology of the disease, sentinel surveillance was established in 5 hospitals in diverse areas of the country in 2001. Data were completed for patients meeting the case definition for viral hepatitis. Of a total of 5909 patients evaluated, 4189 (70.9%) showed positive antibody markers for hepatitis. Out of those, 40.2% had evidence of hepatitis A virus (HAV) infection, 30.0% hepatitis B virus (HBV) and 29.8% hepatitis C virus (HCV) infection. This surveillance system was useful in identifying the variable endemicity of acute HAV infection in different regions and for better understanding the epidemiology of HBV and HCV infection.

Sentinel surveillance for patients with acute hepatitis in Egypt, 2001-04

Viral hepatitis is a major problem in Egypt. To define the epidemiology of the disease, sentinel surveillance was established in 5 hospitals in diverse areas of the country in 2001. Data were completed for patients meeting the case definition for viral hepatitis. Of a total of 5909 patients evaluated, 4189 [70.9%] showed positive antibody markers for hepatitis. Out of those, 40.2% had evidence of hepatitis A virus [HAV] infection, 30.0% hepatitis B virus [HBV] and 29.8% hepatitis C virus [HCV] infection. This surveillance system was useful in identifying the variable endemicity of acute HAV infection in different regions and for better understanding the epidemiology of HBV and HCV infection

Laboratory-based surveillance of patients with bacterial meningitis in Egypt (1998-2004).

Laboratory-based surveillance for bacterial meningitis was conducted in a network of infectious disease hospitals in Egypt to better understand the epidemiology of this infection. Healthcare and laboratory personnel were trained in basic surveillance and microbiologic processing of cerebrospinal fluid (CSF) specimens. All bacterial isolates from CSF were confirmed and tested for antimicrobial susceptibility. PCR testing was performed on a random subset of purulent, culture-negative CSF specimens. Of 11,070 patients who met criteria for the case definition, 843 (8%) were culture positive (42% positive for Streptococcus pneumoniae, 20% for Haemophilus influenzae serotype b, 17% for each of Neisseria meningitidis and Mycobacterium tuberculosis, and 6% for other bacteria). Of 1,784 (46%) CSF specimens tested by PCR, 232 (13%) were positive for the first three major pathogens. Of N. meningitidis isolates, 52% belonged to serogroup A, 35% to serogroup B, and 4% to serogroup W135. S. pneumoniae isolates comprised 46 different serotypes, of which 6B, 1, 19A, 23F, and 6A were the most predominant. The overall case-fatality rate for culture-positive cases was 26% and was highest among patients with M. tuberculosis (47%). Factors significantly associated with death (p < 0.05) included admission to rural hospitals, long prodromal period, referral from other hospitals, antibiotic treatment prior to admission, and clear CSF (<100 cells/mm3). Susceptibility to ampicillin and ceftriaxone was observed in 44 and 100% of H. influenzae serotype b isolates and in 52 and 94% of S. pneumoniae isolates, respectively. This surveillance highlights the significant mortality and morbidity associated with bacterial meningitis in Egypt. Decision makers need to review current treatment guidelines and introduce appropriate vaccines for prevention and control of the disease.

Evaluation of a rapid-format antibody test and the tuberculin skin test for diagnosis of tuberculosis in two contrasting endemic settings.

OBJECTIVE AND SETTING: We evaluated a rapid-format antibody card test and the tuberculin skin test for diagnosis of active tuberculosis (TB) in high (Cairo, Egypt) and low (St. Louis, USA) prevalence areas. DESIGN: Prospective study of hospitalized TB patients and controls with other chest diseases. RESULTS: Test performance varied significantly in the two study sites. The antibody test detected 87% of 71 smear-positive pulmonary TB cases (86% of smear-negative pulmonary cases and 48% of TB meningitis cases) in Egypt; specificity was 82%. The tuberculin test was highly sensitive in Egypt in subjects with pulmonary TB (100%) but not in those with meningitis (23%); specificity was 70%. The sensitivity and specificity of the antibody test in St. Louis were 29% and 79%, respectively; 50% of St. Louis TB cases and 15% of controls had positive tuberculin tests. CONCLUSIONS: This convenient antibody card test may have value for diagnosis of patients suspected of having TB in high prevalence areas like Egypt. However, the specificity of the test is too low for it to be useful as a screening test. Our results suggest that neither the antibody test nor the tuberculin test have much diagnostic utility in low prevalence settings like St. Louis.

Seasonality as a determinant of the efficacy of praziquantel in population-based chemotherapy: lessons from the practice.

During October-November 1991, 1356 male farmers, 18-40 years old from a village in Fayoum Governorate, Egypt, were examined for Schistosoma haematobium infection. The prevalence of infection was 22.2%. Infected farmers were treated immediately with praziquantel at the recommended dose of 40 mg/kg body weight in a single, oral dose. Twelve weeks after treatment 86/262 (32.8%) infected farmers were negative for S. haematobium eggs in urine. In another study conducted in a satellite village in the Nile Delta (Beheira Governorate) where S. mansoni infection is prevalent, all residents of both sexes between 5 and 50 years of age (n = 858) were examined for S. mansoni. The prevalence of S. mansoni was 69.0%. Infected subjects were treated with the same dose of praziquantel during January-February 94, with an overall resultant efficacy of 85.5% (471/551) and 97.2% (103/106) in 18-40 years old males 8-10 weeks post treatment. The high cure rate in the second study was probably because treatment took place 2 months after the end of the high transmission season.

Immunogenicity of recombinant hepatitis B vaccine among infants of mothers with active schistosomiasis.

A study of the immunogenicity of a recombinant hepatitis B vaccine was conducted among 385 Egyptian infants, 191 (49.6%) of whom were born to mothers with moderately active Schistosoma mansoni infection (mean egg count = 224 eggs/g of feces). All mothers were seronegative for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen. Infants were vaccinated with a 2.5-microg dose of this vaccine, given along with diphtheria, tetanus, and pertussis (DTP) vaccine, at the ages of two, four, and six months. Serum samples taken from each infant at nine months of age were tested for HBsAg, antibody to hepatitis B core antigen, and quantitatively for antibody to hepatitis B surface antigen (anti-HBs). There was no significant difference (P = 0.1) between anti-HBs titers in infants of S. mansoni-infected mothers (mean = 539 mIU/ml) and in infants of noninfected mothers (mean = 377 mIU/ml). This study shows that there was no apparent effect of maternal schistosomiasis infection on the immune response of these infants to vaccination.

Praziquantel in the treatment of Schistosoma mansoni infection: comparison of 40 and 60 mg/kg bodyweight regimens.

Two different regimens of praziquantel, 40 mg/kg in a single dose and 60 mg/kg in two divided doses administered 6 hr apart, for the treatment of Schistosoma mansoni infection were compared in Abu Homos, Egypt. Participants in this study included 1,588 subjects of both sexes between five and 50 years old from two rural communities; 730 from Farshout and 858 from Om El-Laban. The prevalence of S. mansoni infection was 57.9% in Farshout and 69.0% in Om El-Laban. Infected subjects received 60 mg/kg of praziquantel in two divided doses 6 hr apart at Farshout and 40 mg/kg in a single dose at Om El-Laban. Eight to ten weeks after treatment, three stool samples were collected from each treated subject on three consecutive days and evaluated quantitatively by the modified Kato technique. The failure rate was significantly higher at Om El-Laban than at Farshout (14.5% versus 4.1% (odds ratio [OR] = 3.95, P < 0.0001). A significantly higher failure rate was consistent after adjustment for age and number of excreted S. mansoni eggs per gram of feces before treatment (OR = 3.75, P < 0.0001). In spite of differences among cure rates between the two regimens, we recommend 60 mg/kg on an individual basis but not for population treatment, since administration of a single dose of a drug is more practical than two doses given 6 hr apart.

Effect of two single doses of ivermectin in treatment of asymptomatic bancroftian filariasis in two villages in the Nile Delta, Egypt.

To evaluate the efficacy and longitudinal effect of two single (100 micrograms/kg) doses of ivermectin, 3 months apart, 240 asymptomatic male subjects from 2 endemic Egyptian villages were enrolled in a one-year double-blind study. Subjects aged 15-55 years were randomly assigned placebo (40) or ivermectin (200). Microfilaria (MF) density in 1 ml blood was measured by membrane filtration before and every 3 months after treatment. Initial mean MF density was 462 (range 14-2869/ml). Clinical examination performed daily for 3 days after each treatment revealed brief, mild side effects: fever, headache, weakness, nausea, and epigastric pain, with no adverse physical or laboratory findings. Three months after initial dose, 31% of MF counts had completely cleared; in the remainder, mean MF density was 11.0 (2.4% of pretreatment level). At 3, 6 and 9 months after the second dose there was complete MF clearance in 60%, 45% and 47%; in those still infected, MF densities were 1.7, 4.6 and 6.1% of the pretreatment level. Therefore, treatment with two doses of ivermectin reduced microfilaremia, without inducing severe side effects. Prolonged suppression of microfilaremia may indicate an effect of ivermectin on the adult worms and may reduce the potential for MF acquisition by mosquitoes, reducing transmission of lymphatic filariasis. It was concluded that ivermectin is a useful drug for public health measure, including asymptomatic filariasis patients.

Prevalence of intestinal parasites in filariasis endemic areas in Egypt.

Stool and blood specimens were collected from 230 individuals of both sexes at 2 villages (Qualyubia Governorate) where filariasis is endemic. The overall prevalence of parasites was 81%, while it was higher (92.4%) among filariasis patients than non infected individuals (50%). On the other hand, the level of microfilaria (MF) in the blood apparently showed an influence on the prevalence of parasitic infection in the infected individuals. However, in all groups, E. histolytica was the commonest protozoal parasite followed by G. lamblia. As regard helminthic infections, S. mansoni was the commonest followed by E. vermicularis. These data suggest that filariasis as an endemic disease may suppress the immune response of the host and under such circumstances, the susceptibility for other infections become higher.

Vector-host-parasite inter-relationships in leishmaniasis. I. The effect of Leishmania parasites on rate of digestion of blood proteins from various vertebrate hosts by the sand fly Phlebotomus langeroni (Diptera: Psychodidae).

Protein digestion in the gut of Phlebotomus langeroni (Nitzulescu) was studied at four subsequent 24 hour intervals post feeding on human, dog (Canis familiaris), rat (Rattus rattus) and turkey (Melagris gallopava) bloods with and without Leishmania infantum or L. major promastigotes. Most of the proteins of the studied blood meals were digested within 96 hours. The percent of blood proteins digested in the first 48 hours was higher than in the second 48 hours in all cases of the studied blood meals except the normal blood of the turkey in which the ratio of the digested blood proteins in the two periods was 1:1. During the first 48 hours, the percent of the digested blood proteins was lower than normal in the presence of L. infantum in case of human and dog blood meals. The reverse was true in case of the rat and turkey blood meals in the presence of L. infantum and in the blood meals from each of the four vertebrate hosts in the presence of L. major. The significance of these findings in considering L. infantum as a natural parasite of P. langeroni in El Agamy focus was discussed.

Vector-host-parasite inter-relationships in leishmaniasis. II. Influence of blood meal from natural vertebrate hosts with and without Leishmania infantum and L. major on the proteolytic activity in the gut of Phlebotomus langeroni (Diptera: Psychodidae).

Proteolytic activity in the gut of Phlebotomus langeroni (Nitzulescu) was studied at four subsequent 24 hours intervals post feeding on human, dog (Canis familiaris), rat (Rattus rattus) and turkey (Melagris gallopava) bloods with and without Leishmania infantum or L. major promastigotes. The gut proteolytic activity increased gradually after feeding to reach a maximum at 48 hours post feeding on any of the 12 studied blood meals. In all cases, the activity declined after 48 hours and almost terminated by 96 hours. In case of normal bloods, the proteolytic activity, at 48 hours post feeding, was the highest in case of dog followed by human, rat and turkey respectively. At this time interval the activity was relatively lower in case of human and dog blood mixed with L. infantum promastigotes than in their respective normal blood. The reverse was true in all other blood meal combinations. Promastigotes were alive and active in fresh gut smears of P. langeroni fed on human, dog and rat bloods mixed with either L. infantum or L. major, throughout the digestion period (1-4 days). They were arrested in P. langeroni within the first day post feeding on turkey blood mixed with either Leishmania species. The results of the present study indicate that the kind of blood meal and the Leishmania species affect the proteolytic activity of P. langeroni. The decrease or increase of the proteolytic activity of P. langeroni has no effect on the survival of Leishmania parasites present in the gut and the kind of blood meal is responsible for their development.

Vector-host-parasite inter-relationships in leishmaniasis. III. Impact of blood meal from natural vertebrate hosts on the survival and the development of Leishmania infantum and L. major in Phlebotomus langeroni (Diptera: Psychodidae).

Phlebotomus langeroni collected from a leishmaniasis endemic focus at Et Agamy, Alexandria, Egypt, were found to have fed on blood from man, dogs (Canis familiaris) and rats (Rattus rattus). The effect of the kind of blood meal on the development and the life-cycle of L. infantum and L. major in laboratory reared P. langeroni was therefore investigated. A membrane feeding technique was used to infect sand flies. Gut smears of infected females were examined immediately after feeding and daily for 16 days. Nectomonads and short promastigote forms of L. infantum or L. major were detected in females fed on human, dog and rat bloods at all intervals. Paramastigotes (infective stage) were present only in females fed on dog blood containing L. infantum or L. major and in those fed on rat blood containing L. major. It is concluded that among the factors influencing the Leishmania-phlebotomus relationship is the natural medium in which the parasite is present in vivo. The blood of the natural reservoir host(s) is the key factor for the development of the infective parasite form in the sand fly and P. langeroni could be considered a potential vector for transmitting L. infantum from dogs and L. major from rats and dogs but not from man. This investigation offers a new concept for the study of interactions among vector, host and parasites in Leishmania transmission.

Vector-host-parasite inter-relationships in leishmaniasis. IV. Electrophoretic studies on proteins of four vertebrate bloods with and without Leishmania infantum or L. major.

Fifty five protein bands with relative mobilities of 8,954 to 245,471 kilo Daltons (kD) were electrophoretically separated from 12 feeding media of blood from 4 natural vertebrate hosts of Phlebotomus langeroni. The feeding media included human, dog (Canis familiaris), rat (Rattus rattus) and turkey (Melagris gallopava) bloods without or with Leishmania infantum or L. major promastigotes. Protein bands were identical among the feeding media of one host's blood but varied in number (24-28 bands) and relative mobilities among the various hosts' blood. Some protein fractions were common among the various hosts blood, others were only present in two or three hosts' blood and some were restricted to one host blood and were unique for each host. This study provides data which may help in understanding why blood from different natural hosts may variably influence the life cycle of Leishmania parasite in the sand fly gut.

Amebiasis in schistosomiasis endemic and non-endemic areas in Egypt.

Stool and blood specimens were collected from each of 404 and 576 individuals at Sindbis village (Qualiubia Governorate) in the Nile Delta where schistosomiasis is endemic and El-Rashda village (New Valley Governorate) in the Western Desert of Egypt where there is no schistosomiasis; respectively. Based on the microscopical examination of stool specimens, the prevalence of infection with Entamoeba (E. histolytica and/or E. dispar which are morphologically indistinguishable) was higher at Sindbis than at El Rashda village (29.3% and 20%, respectively). At Sindbis, the prevalence of Entamoeba (both species) was 35.2% (50/142) in S. mansoni infected individuals versus 26.3% (69/262) in S. mansoni negative individuals. Serum antibodies develop only against E. histolytica but not against E. dispar infection. When serological results were considered, the prevalence of E. histolytica was 4.7% in Sindbis and 3.4% at El Rashda based on those who were positive microscopically and serologically in the two villages, respectively. In other words, only 16-17% of those who were positive microscopically can be considered infected with E. histolytica as determined serologically. However, the prevalence of E. histolytica (present or past) based on those who were positive serologically whether positive or negative microscopically was 13.4% and 12.7% at the two villages, respectively. At Sindbis, the prevalence of E. histolytica infection was lower in S. mansoni negative (8.5%) than in S. mansoni positive (16.0%) individuals. These epidemiologic data suggest that: (1) S. mansoni infection may suppress the immune response of the host and therefore, the prevalence of E. histolytica based on serological testing is probably underestimated in the S. mansoni infected people and it may be higher than in the S. mansoni negative people. (2) Serological examinations can be used in determining the true prevalence of E. histolytica (present or past infections) until a routine test for detecting E. histolytica specific antigen in stool becomes available to differentiate E. histolytica from E. dispar infections.

Studies on the most reactive purified antigen for immuno-diagnosis of hydatid disease.

Fourty hydatidosis patients and 36 patients with various parasitic diseases taken from Ain Shams University Hospitals and 15 normal controls as well were subjected to clinical examination, stool and urine examination, serological examination using indirect hemagglutination (IHA), counterimmunoelectrophoresis (CIEP) and enzyme-linked immunosorbent assay (ELISA) tests with crude and partially antigens for hydatidosis. Partial purification of crude hydatid fluid antigen abolished reactions in IHA test, reduced in ELISA or had no effect on cross reactions in the CIEP test. The crude antigen was more sensitive than the purified antigen in all tests applied. Using crude antigen, IHA (83%) was the most sensitive test followed by ELISA (68%) and then CIEP (60%) tests. In case of partially purified hydatid fluid antigen, CIEP was the most sensitive (58%) test with the purified peak I antigen followed by IHA test with peak III (48%) then ELISA with purified peak I (45%). In all serological tests applied, hepatic hydatidosis cases gave the highest reactions followed by cases of combined hepatic and pulmonary infections and then pulmonary cases alone.

Leishmania tropica in Egypt: an undesirable import.

Cutaneous as well as visceral leishmaniasis has been previously reported in Egypt. The former clinical manifestation is attributed to Leishmania major, the latter to L. infantum. In this study, L. tropica was isolated from an Egyptian labourer returning from Saudi Arabia. Amastigotes were detected by both Giemsa staining and indirect immunofluorescence using rabbit anti-gp63. Promastigotes from Schneider's medium were typed isoenzymatically as L. tropica. In view of the emerging threat of visceralization of L. tropica, the potential risk for its transmission in Egypt is discussed.

Evaluation of crude and purified Toxocara canis antigens in serodiagnosis of human toxocariasis.

Three serological tests: Immunodiffusion (ID), Counterimmunoelectrophoresis (CIEP) and Enzyme-linked immunosorbent assay (ELISA) were used to study the role of crude adult worm antigen (CAWA) of Toxocara canis and each of its purified fractions in the serodiagnosis of human toxocariasis. Sensitivities of the three tests were lower in the ocular than in the visceral group, using different antigens. Purified fraction 1 showed more sensitive and specific reactions in the three tests, compared to CAWA or purified fraction 2 (P-F2) antigen. The other purified fractions (P-F3, P-F4 and P-F5) gave no positive reactions in any of the three tests. Using P-F1 antigen, ELISA was the most sensitive technique for diagnosis of both visceral and ocular toxocariasis followed by CIEP and then ID and the difference was statistically significant. However, CIEP was the most specific test followed by ELISA and lastly ID test. The ELISA test using Excretory-Secretory (E-S) larval antigen of Toxocara canis was less sensitive than the ELISA test using P-F1, although it was 100% specific. Thus, ELISA test using P-F1 is the test of choice for diagnosis of human toxocariasis, but when the specificity of a reaction is in doubt, CIEP test using the same antigen can be of value.