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Vaccination remains the primary preventive strategy in the elderly against Streptococcus pneumoniae and influenza infections. However, the effectiveness of vaccines decreases with increasing age and among patients. This study evaluated the opportunistic parasites infecting vaccinated and non-vaccinated pneumococcal children. The result showed that Invasive children (4%) had bacternrmid, septicemid and pneumococcal but no meningitis while the non-invasive ones (86%) had community acquired freunonia and otitis media. The non-vaccinated children were at risk of Ascaris lumbricoides, Ancylostoma duodenale, Trichuris trichura, Schistosoma mansoni, S. haematobium, bancroftian microfilaria, Enterobius vermicularis, Hymenolepis nana, Giadia lamblia, Entaemeba histolytica and Trichomonas vaginalis.

Parasitic infections might become life threatening in immuno-compromised children' The study assessed the parasites' prevalence in different groups of immuno-compromised children. It was conducted on 120 children of whom 90 were inpatients in Tanta University Pediatric Hospital and were divided into 6 groups. GI: malignant diseases, GII: renal diseases, GIII: aggressive corticosteroid therapy, GIV: malnourished, GV: diabetic & GVI: miscellaneous. GVII comprised healthy children as control. Each child was subjected to history taking, clinical examination and examination of 3 stool samples by direct wet smear and a concentration technique. Coproculture and smear staining by a special stain, as well as examination of one blood sample for anti-Toxoplasma antibodies were done. The diagnostic efficacy of an immuno-chromatographic test for Giardia/ Cryptosporidium coproantigen was also assessed. The results revealed parasitic infections in 62.2% of the children in the test groups. Cryptosporidium was the most prevalent (33.3%). Cryptosporidium and Microsporidia were significantly prevalent in GI, Giardia was significantly high in GII, and Strongyloides stercoralis was detected in GIII. Coproantigen detection test showed 100% sensitivity, 87.5% specificity and 95% accuracy for Giardia; and 13.3%, 100%, 35% for Cryptosporidium respectively.

Three hundred children with hepatomegaly were selected. They were subjected to full clinical and laboratory examinations. Also serum samples were examined to detect IgG using ELISA against SEA, chromatography purified hydatid cyst antigen, commercially available Toxoplasma antigen, partially purified adult Fasciola antigen and second-stage larvae Toxocara canis antigen. IFAT was used to detect IgG against Toxoplasma and T. canis. A commercially available IHAT kit for leishmaniasis was used. Based on immunological assays, 125 cases were suffering from various parasitic infections. Thirty cases with schistosomiasis (10%), 26 cases fascioliasis (8.7%), 18 toxocariasis (6%), 35 toxoplasmosis (11.7%), 3 cases hydatidosis (1%) and 13 cases mixed parasitic infections. No parasitic causes could be found in 175 cases (58.3%). Moderate or marked hepatomegaly favours the presence of schistosomiasis. Whereas, most cases with other parasites and those with non-parasitic infections fall in the category of mild hepatic enlargement. There was no associated splenomegaly in cases with Fasciola, Toxocara, hydatid disease and/or the non-parasitic group. Most of hepatomegalic cases with non-parasitic causes were found to be associated with fever (88.5%). Fever was found in nearly 50% of cases with either Toxoplasma or Toxocara infections. Mild eosinophilia was found in all cases with parasitic causes. Only 24 cases of non-parasitic group (13.7%) had easinophilia. Moderate and high eosinophilia were found in cases with fascioliasis and toxocariasis. Cases with fascioliasis had a statistically significant increase in enzymes activities specially alkaline phosphatase. It was concluded that parasitic infections should be considered as an important cause of liver enlargement in children. Serological methods using purified antigenic fractions are an important tool for diagnosis.

The relationship between asthma, IgE and parasite infection was compared in 68 randomly selected patients with asthma and 37 nonasthmatic controls living in Tanta, Egypt. Sera were assayed for total IgE and for IgE antibodies to inhaled allergens (mite, cat, cockroach, ryegrass, ragweed and 3 fungi) and to parasite antigens (Schistosoma mansoni and Brugia malayi). Parasite infection was determined by microscopic examination of stool specimens. Total IgE levels were significantly higher in patients with asthma (geometric mean 909 IU/ml), than in controls (geometric mean 145 IU/ml, p less than 0.001). The high IgE levels correlated with parasite infection and the presence of IgE antibodies to S. mansoni antigens, which were also elevated compared to controls. The prevalence of allergen-specific IgE antibodies among Egyptian asthmatics was low by comparison with 'Western' asthmatics, but nonetheless higher than among Egyptian controls. A radioallergosorbent test (RAST) values of greater than 40 U/ml to any allergen was found in 19/68 (28%) sera from the asthma group, as compared to only 1/37 (3%) sera from controls (p less than 0.001). The highest RAST values were to dust mite (Dermatophagoides pteronyssinus and D. farinae) allergens, followed by rye grass and ragweed allergens. The results suggest that in this area of Egypt, several factors may influence the development of asthma, including nonspecific activation of IgE and/or inflammatory mechanisms by helminth parasites and sensitisation to environmental allergens.