Isolation and Identification of Pathogenic Acanthamoeba Species from Air Conditioning Systems, Egypt.

Acanthamoeba are free-living amoebae that cause granulomatous amoebic encephalitis and keratitis. In this study, we aimed to isolate and identify Acanthamoeba from air conditioning systems using in vitro cell culture and polymerase chain reaction assays. We also estimated the pathogenicity of the isolates by measuring their thermotolerance and studying mice models inoculated with these isolates. Of the 80 dust samples acquired, 41 (51.25%) were found to be positive for Acanthamoeba spp. using in vitro cell culture and the results were validated using PCR. Out of these 41 samples, 27 (65.9%) were thermotolerant and 16 (39%) samples could infect mice and cause histopathological effects. Highly pathogenic Acanthamoeba isolates were characterized by their thermotolerance and the ability to disseminate in all organs after infection, causing early death of infected animals. Our study thus validated the presence of pathogenic isolates of Acanthamoeba in air conditioners that may be potentially infectious to humans.

Polymerase Chain Reaction: A Better Method for Diagnosing Chronic Schistosoma mansoni Infections.

For more effective diagnosis of the acute and chronic stages of Schistosoma mansoni infection in humans, the polymerase chain reaction (PCR) technique was compared with the Kato-Katz method. A total of 150 stool samples were collected from inpatient and outpatient clinics at the Department of Tropical Medicine, Minia University Hospital, Egypt. Three groups of patients, 50 with acute intestinal schistosomiasis, 70 with chronic intestinal schistosomiasis and 30 normal healthy controls were studied. Stool samples were analyzed by PCR and the Kato-Katz method. The mean number of eggs per gram of feces was 4.6 when estimated by the Kato-Katz method in positive stool samples from acute schistosomiasis cases but only 1.7 in chronic cases. In acute intestinal schistosomiasis, 15 and 45 out of 50 cases were positive by Kato-Katz and PCR, respectively. In the chronic intestinal schistosomiasis cases, 6 and 68 out of 70 cases were positive by the Kato-Katz and PCR methods, respectively. We conclude that PCR appears to be an effective diagnostic technique for S. mansoni infection, especially where a low worm burden exists, such as in chronic cases.

PARASITES TRANSMITTED TO HUMAN BY INGESTION OF DIFFERENT TYPES OF MEAT, EL-MINIA CITY, EL-MINIA GOVERNORATE, EGYPT.

Meat-borne parasites are Sarcocystis species, Toxoplasma gondii, Taenia saginata, Taenia solium and Trichinella spiralis. A total of 300 animals including 100 cattle, 100 goat, and 100 pigs, slaughtered in El-Minia governmental slaughterhouses. From each animal, five samples were taken from different muscles (esophageal, tongue and cardiac) and different organs (liver and brain). Meat samples were examined macroscopic and microscopic (direct, homogenization and H&E staining) for detection of the above-mentioned parasites. Serum samples were subjected to IHA for detection of T gondii specific antibodies. This study revealed that Sarcocystis species were the highest parasites that could be detected, with overall prevalence of 80%, which was statistically significant (P < or = 0.001). The digestion method was more sensitive than direct method for detection of Sarcocystis species. On the other hand, T. gondii was only diagnosed by using IHA test as 50.9% serum samples were positive, which was statistically significant (P < or = 0.004). Besides, 20% of examined battle were infected by Cysticercus bovis, and 12% of pigs were infected with C. cellulosae, but without statistical significant (P < or = 0.5).

Pilot Study on Interferon-γ-producing T Cell Subsets after the Protective Vaccination with Radiation-attenuated Cercaria of Schistosoma japonicum in the Miniature Pig Model.

CLAWN miniature pig has been shown to serve as a suitable host for the experimental infection of Schistosoma japonicum. In this study, we found that radiation-attenuated cercaria (RAC) vaccine gave CLAWN miniature pigs protective immunity against subsequent challenge infection with S. japonicum cercaria. To characterize the protective immune response of the pig model vaccinated by attenuated cercaria, flow cytometric analysis of the reactive T cell subsets was performed. The intracellular interferon (IFN)-γ and the cell surface markers revealed the peripheral blood CD3+ T-lymphocytes produced significant amounts of IFN-γ during the immunization period and after the challenge infection. CD4+ αß-T cells as well as CD4+/CD8α(mid) double positive and/or CD8α(high) αß-T cells were the major IFN-γ-producing CD3+ T cells. On the contrary, γδ T cells did not produce intracellular IFN-γ. Our results suggested that RAC-vaccinated miniature pigs showed effective protective immunity through the activation of αß T cells bearing antigen specific T-cell receptors but not through the activation of γδ T cells.

Breast-feeding protects infantile diarrhea caused by intestinal protozoan infections.

This study investigated the effect of breast-feeding in protection against protozoan infection in infants with persistent diarrhea. Infants were classified into 2 groups; 161 breast-fed infants and the same number of non-breast-fed infants. Microscopic examinations of stool were done for detection of parasites and measuring the intensity of infection. Moreover, serum levels of IgE and TNF-α were measured by ELISA. Cryptosporidium spp., Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, and Blastocystis sp. were demonstrated in infants with persistent diarrhea. The percentage of protozoan infections was significantly lower in breast-fed infants than that in the non-breast-fed infants. The levels of IgE and TNF-α were significantly lower in the breast-fed group than in the non-breast-fed group. There were significant positive associations between the serum levels of IgE and TNF-α and the intensity of parasite infection in the breast-fed group. It is suggested that breast-feeding has an attenuating effect on the rate and intensity of parasite infection.

Cutaneous leishmaniasis in the Nalut District, Libyan Arab Jamahiriya: a clinico-epidemiologic study and Leishmania species identification.

Cutaneous leishmaniasis (CL), an endemic disease in the littoral zones of the Mediterranean area, the Middle East, East Africa, and especially in Libya, has not been fully documented. The present study clarifies the clinico-epidemiologic profile of CL and the molecular genotyping of the Leishmania spp. in the Nalut district, Libya. Two hundred and twenty-three CL patients were examined at the out-patient clinics of Nalut Hospital from March 2006 to February 2007. CL was diagnosed by clinical, microscopic, culture, polymerase chain reaction (PCR), and PCR-restriction fragment length polymorphism (RFLP) analyses. The disease was observed year-round, with the highest prevalence between November and February. Fifty-nine percent of patients were younger than 20 yr. Nodulo-ulcerative lesions, indurated ulcers, papulo-ulcerative lesions, and subcutaneous nodular lesions were observed in 170, 25, 15, and 13 patients, respectively. Two hundred patients (89.7%) had dry type of lesions, whereas 23 patients (10.3%) presented a wet type of lesion. One hundred and fifty-nine (71.3%) of 223 patients were confirmed positive for CL by the presence of the amastigote form of Leishmania by stained Giemsa smear, and 170 (76.2%) were positive according to the presence of the promastigote form of Leishmania by culture in RPMI 1640 medium supplemented with 10% fetal bovine serum (FBS). PCR confirmed 203 (91.0%) positive cases. Genotyping of Leishmania spp. by RFLP analysis revealed that L. tropica was the most common species at all ages, and L . infantum was second under 20 yr of age. In summary, CL is endemic in the Nalut district, Libya; PCR was the most sensitive parasite diagnostic test, and L. tropica was the most common species.

Proteome approach for identification of schistosomiasis japonica vaccine candidate antigen.

Experimental vaccination with radiation-attenuated cercariae (RAC) confers possible practical levels of resistance to challenge infection by humoral and by cellular mechanism. Here, we aimed to identify possible vaccine antigens by using specific IgG antibody from RAC vaccinated miniature pig. Two milligrams of soluble egg antigen (SEA) or schistosomal worm antigen preparation (SWAP) was fractionated using two dimensional liquid chromatography (proteome PF 2D) consisted of high performance chromatofocusing (HPCF) and high resolution reversed phase chromatography (HPRP). Of the 42 HPCF fractions of SEA or SWAP, 26 (61.9%) or 15 (35.7%) showed positive dot blot reaction with RAC vaccinated serum respectively. The dot blot positive fractions were applied to the second HPRP column. One hundred and seven out of 26 x 96 of SEA fractions and 18 out of 15 x 96 SWAP fractions reacted with RAC vaccinated serum. From the positive fractions we chose 17 of SEA and 10 of SWAP that had no reactivity with normal cercariae infected (NCI) sera and had single peak of 214 nm; and automated N-terminal amino acid sequence based on in situ Edman Reaction was conducted. Four sequences were obtained and applied to the homology search in NCBI database. A total of eight candidate genes were listed up and their cDNA clones from schistosomula stage were obtained. Two of the recombinant proteins (AAW27472.1 and AXX25883.1) showed strong reactivity with the RAC vaccinated serum but marginal with NCI serum. This protocol using proteome PF 2D could be applicable in identifying immunoreactive proteins from crude extract for the development of vaccines or for diagnostics.