Viral etiologies of lower respiratory tract infections among Egyptian children under five years of age.

BACKGROUND: Lower respiratory tract infections (LRTI) are responsible for a considerable number of deaths among children, particularly in developing countries. In Egypt and the Middle East region, there is a lack of data regarding the viral causes of LRTI. In this study, we aimed to identify the relative prevalence of various respiratory viruses that contribute to LRTIs in young children. Although, nucleic acid-based methods have gained importance as a sensitive tool to determine the viral infections, their use is limited because of their prohibitive cost in low-income countries. Therefore, we applied three different laboratory methods, and presented the different virus prevalence patterns detected by each method. METHODS: We collected nasopharyngeal aspirate samples, demographic data and, clinical data from 450 children under five years of age who presented with LRTI at Abou El Reesh hospital in Cairo during a one-year period. To identify the viral causes of the LRTI we used direct fluorescence assay, real-time reverse-transcriptase polymerase chain reaction (rt-RT-PCR), and shell vial culture. We tested for eight major respiratory viruses. RESULTS: Two hundred sixty-nine patients (59.9%) had a viral infection, among which 10.8% had a co-infection with two or more viruses. By all three methods, respiratory syncytial virus (RSV) was the most predominant, and parainfluenza virus type 2 (HPIV-2), influenza B virus (FLUBV) were the least predominant. Other viral prevalence patterns differed according to the detection method used. The distribution of various viruses among different age groups and seasonal distribution of the viruses were also determined. CONCLUSIONS: RSV and human adenovirus were the most common respiratory viruses detected by rt-RT-PCR. Co-infections were found to be frequent among children and the vast majority of co-infections were detected by nucleic acid-based detection assays.

Comparison of direct fluorescence assay and real-time rt-PCR as diagnostics for respiratory syncytial virus in young children.

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infections in children worldwide. Early detection of RSV is critical to initiate proper care. Two methods, the direct fluorescence assay (DFA) and the real-time reverse-transcription polymerase chain reaction (rt-RT-PCR), that are used for RSV detection were compared. A total of 451 nasopharyngeal aspirates from children 5 years of age or less were tested for RSV using both methods. The overall prevalence rate of the RSV among the children was 23.7% with a significantly higher prevalence among children under the age of 6 months of age when compared to other age groups. The sensitivity of DFA in comparison to rt-RT-PCR was highest (86%) during the first 3 days of symptoms onset and decreased gradually till it reached 65% after the first week. The specificity of DFA in comparison to rt-RT-PCR ranged between 99 and 100% irrespective of the date of collection. We concluded that, although the rt-RT-PCR is more sensitive for RSV detection, the DFA offers a reliable point-of-care alternative detection method especially during the first few days of illness.

A review of cryptosporidiosis in Egypt.

Cryptosporidiosis, a parasitic zoonosis, while typically a short-term infection, has a global distribution and can cause severe illness in children and other vulnerable populations. In order to inform local and regional public health personnel and providers, the authors conducted a comprehensive review of Cryptosporidium parvum (Cp) epidemiology in Egypt to establish what is known, identify critical knowledge gaps, and develop a basis for future directions in mitigating the burden associated with this illness among Egyptians and similar countries. A total of 61 published studies between 1985 & 2006 were reviewed. Nineteen studies examined immunocompetent individuals with diarrhea presenting to inpatient or outpatient clinics with a Cp prevalence ranging from 0% - 47% (median 9%, IQR 3-15%). Identified risk factors, at risk populations, ecology, environmental findings, as well as a quality assessment of the published literature are discussed. The building blocks are in place to design studies aimed at defining the disease, societal burden and evaluating public health interventions aimed at disrupting water and zoonotic transmission modalities using the most current molecular techniques. Cp diarrhea is but one of the many causes of diarrhea among Egyptians, but efforts to control this disease should also serve well to mitigate a number of infectious causes of diarrhea and given the track record of previous work hopping to see advances in the near future.

Enteric pathogens associated with diarrhea in children in Fayoum, Egypt.

In a cross-sectional study of children <60 months old from Fayoum, Egypt, presenting with diarrhea, 46% (162/356) had detectable enteric pathogens. Bacterial pathogens were identified in 25% (89/356), whereas rotavirus and Cryptosporidium were detected in 21% (54/253) and 15% (39/253), respectively. Cryptosporidium is an important pathogen in this region.

Differentiation of tuberculous meningitis from acute bacterial meningitis using simple clinical and laboratory parameters.

Tuberculous meningitis (TBM) is still a major cause of serious illness in many parts of the world. The newer diagnostic tests and neuroimaging methods are unlikely to be available in many developing countries. We attempt to identify simple parameters for early diagnosis. A retrospective study was performed to compare the clinical and laboratory features of cultured-confirmed, TBM (134) and other bacterial meningitis (709). Features independently predictive of TBM were studied by multivariate logistic regression to develop a diagnostic rule. Six features were found predictive: length of clinical history >5 days, headache, total cerebrospinal fluid (CSF) white blood cell count of <1000/mm3, clear appearance of CSF, lymphocyte proportion of >30%, and protein content of >100 mg/dL. Application of 3 or more parameters revealed 93% sensitivity and 77% specificity. Applying this diagnostic rule can help in the early diagnosis of TBM, in both children and adults.

Hospital-based surveillance for acute febrile illness in Egypt: a focus on community-acquired bloodstream infections.

Acute febrile illness (AFI) is a common syndrome in Egypt. However its etiologies are not well characterized. To determine the relative frequency of pathogen etiologies and possibly improve diagnostic, clinical management and public health measures, we implemented laboratory-based surveillance in a network of infectious disease hospitals throughout Egypt. Admitted patients with AFI provided background details and a blood sample for bacterial culture and serologic analysis. Case definitions were based on laboratory results. Of 10,130 patients evaluated between 1999 and 2003, 5% were culture positive for Salmonella enterica serogroup Typhi, 3% for Brucella, and 2% for other pathogens. An additional 18% of patients had positive serologic results for typhoid and 11% for brucellosis. Risk factor analysis identified availability of municipal water to be significantly (P < 0.05) associated with protection against typhoid. Animal contact and consumption of raw dairy products were significantly associated with brucellosis. The surveillance network identified typhoid fever and brucellosis as the most common bacterial causes of AFI in Egypt, allowed better description of their epidemiology, and may lead to the development of targeted prevention strategies.

Etiology, antimicrobial susceptibility profiles, and mortality associated with bacterial meningitis among children in Egypt.

PURPOSE: Surveillance for patients with meningitis is a high priority in order to determine the etiology of disease and design prevention strategies. This study presents data on the causes of bacterial meningitis among children <6 years of age treated in a network of hospitals throughout Egypt. METHODS: Training was provided to standardize the collection of clinical information and optimize recovery of bacterial pathogens. Bacterial isolates were tested for antimicrobial resistance patterns using Kirby Bauer disk diffusion, E-test and/or Beta-lactamase (BL) testing methods. RESULTS: Patients with culture-confirmed bacterial meningitis (228 children<6 years) were identified including 89 (39%) patients with H. influenzae (HI), 68 (30%) with Streptococcus pneumoniae (SP), 30 (13%) with N. meningitidis (NM), 18 (8%) with Mycobacterium tuberculosis (MTB) and 23 (10%) with other bacteria. The overall case fatality ratio was high (24%) and increased among children with TB meningitis (56%). The susceptibility for HI to ampicillin (AMP), chloramphenicol (C) and ceftriaxone (CRO) was 21%, 13%, and 100% respectively. The susceptibility for SP to C and CRO was 79% and 100%, respectively. CONCLUSIONS: HI and SP are the leading causes of bacterial meningitis among children in Egypt. The majority of HI strains tested were resistant to AMP or C suggesting the need for routine use of CRO as first line therapy. Among older children TB emerges as a significant cause of bacterial meningitis in Egypt.

Estimating the incidence of typhoid fever and other febrile illnesses in developing countries.

To measure the incidence of typhoid fever and other febrile illnesses in Bilbeis District, Egypt, we conducted a household survey to determine patterns of health seeking among persons with fever. Then we established surveillance for 4 months among a representative sample of health providers who saw febrile patients. Health providers collected epidemiologic information and blood (for culture and serologic testing) from eligible patients. After adjusting for the provider sampling scheme, test sensitivity, and seasonality, we estimated that the incidence of typhoid fever was 13/100,000 persons per year, and the incidence of brucellosis was 18/100,000 persons per year in the district. This surveillance tool could have wide applications for surveillance for febrile illness in developing countries.

Introductory evaluation of an oral, killed whole cell enterotoxigenic Escherichia coli plus cholera toxin B subunit vaccine in Egyptian infants.

BACKGROUND: We conducted the first trial to assess the safety and immunogenicity of an oral, killed enterotoxigenic Escherichia coli plus cholera toxin B-subunit vaccine in children <2 years old. METHODS: Three doses of vaccine or killed E. coli K-12 control were given at 2-week intervals to 64 Egyptian infants, 6 to 18 months old, in a randomized, double blind manner. Adverse events were monitored for 3 days after each dose. Blood was collected before immunization and 7 to 10 days after each dose to assess vaccine-specific serologic responses. RESULTS: There was no statistically significant intergroup difference in the percentage of subjects reporting the primary safety endpoint (diarrhea or vomiting) after the first (31%, vaccine; 30%, control) or third (14%, vaccine; 18%, control) dose, whereas there was a trend toward greater reporting in the vaccine group after Dose 2 (36%, vaccine; 18%, control; P = 0.052). The percentage of children showing IgA seroconversion after any dose was higher in the vaccine than the control group for recombinant cholera toxin B-subunit (97% vs. 46%), colonization factor antigen I (61% vs. 18%) and coli surface antigen 4 (39% vs. 4%) (P < 0.001 for each comparison). IgG seroconversion rates in the vaccine and control groups were 97 and 21% to recombinant cholera toxin B-subunit (P < 0.001), 64 and 29% for colonization factor antigen I (P < 0.01), 53 and 21% for coli surface antigen 2 (P < 0.05) and 58 and 4% for coli surface antigen 4 (P < 0.001), respectively. The third vaccine dose was followed by augmented IgG antitoxin titers. CONCLUSION: The oral enterotoxigenic E. coli vaccine was safe and immunogenic in this setting in Egyptian infants.