Diarrhea among African children born to human immunodeficiency virus 1-infected mothers: clinical, microbiologic and epidemiologic features.

Diarrhea and weight loss are common features of pediatric and adult human immunodeficiency type 1 (HIV-1) infection, particularly in developing countries. We studied prospectively episodes of diarrhea in 559 children, ages 10 to 15 months, participating in a longitudinal study of perinatal HIV-1 infection in Kinshasa, Zaire. Children with HIV-1 infection had more frequent episodes of diarrhea and were more likely to present with fever or moderate or severe dehydration and to have persistent or fatal diarrhea. Of 9 HIV-1-positive infants with diarrhea, 3 had enteroadherence factor-positive Escherichia coli, compared with 5 of 74 HIV-1-negative children with diarrhea (P = 0.04); no other pathogen was associated with HIV-1 infection. In a logistic regression model diarrhea was significantly associated with HIV-1 infection in the child, moderate or severe malnutrition and symptoms of acquired immunodeficiency syndrome in the mother. Diarrhea among children with perinatal HIV infection in Zaire is more severe than among uninfected children and is associated with malnutrition and advanced disease in the mother.

An alga-like organism associated with an outbreak of prolonged diarrhea among foreigners in Nepal.

An unidentified organism was found in the stools of 55 immunocompetent patients who presented to the CIWEC Clinic in Kathmandu, Nepal between June and November 1989. The microscopic features of the organism share characteristics of both coccidia and cyanobacteria species. From June 26, 1989 to November 17, 1989, 55 persons were identified as having the organism in at least one stool sample. The illness was characterized by prolonged watery diarrhea, anorexia, fatigue, and weight loss. The mean +/- SD duration of illness was 43 +/- 24 days (range 4-107). Thirty-four patients received a total of 78 courses of antimicrobial treatment (2.3 courses/patient). The mean +/- SD duration of illness in 34 treated patients was 46 +/- 24 days. In 14 untreated patients, the mean +/- SD duration of illness was 35 +/- 23 days. The organism is 8.0-9.0 microns in diameter, floats in Sheather's solution, and stains red with the modified acid-fast stain. Since the agent was closely associated with a prolonged, self-limited diarrheal illness, it could easily have been misdiagnosed as Cryptosporidium. The organism should be looked for in the stools of patients with persistent diarrhea and a history of foreign travel.

Chronic relapsing colitis due to Strongyloides stercoralis.

The small intestine is the usual site of chronic infection with Strongyloides stercoralis. Colonic involvement has generally been seen in the hyperinfection syndrome in immunosuppressed individuals. We describe an immunologically competent female who underwent multiple abdominal operations over a 5-year period for hematochezia and diffuse abdominal pain of obscure etiology. Eosinophilia had been present but never investigated until 1981, at which time stool examination revealed S. stercoralis larvae. Pathological specimens from operations in 1977 and 1981 demonstrated extensive colonic wall invasion with filariform larvae consistent with S. stercoralis. Involvement of other organs was never documented. We believe this case is consistent with chronic colitis due to strongyloidiasis. This entity has not been previously described, and expands the spectrum of this disease.

Changes in the virulence of Mycobacterium avium after passage through embryonated hens' eggs.

Eight-day-old embryonated hen's eggs were used as a model to study Mycobacterium avium virulence. Strains isolated from human patients caused 20-90% mortality when eggs were infected by injection of bacterial suspensions into the amniotic sac. Virulence of examined strains subsequently decreased with passage through eggs to between 0 and 40% mortality in four passages. Virulence of the egg-attenuated strains could be restored by passage through human peripheral blood mononuclear cells. The site of infection in the egg was usually the mesodermal layer of the chorioallantoic membrane. A few small granulomas containing acid-fast bacteria were seen in the liver, but not in other organs. Death of chicken embryos may have resulted from destruction of the mesodermal layer of the chorioallantoic membrane with consequent respiratory failure. PBMCs infected with less virulent egg-passaged strains of M. avium produced higher levels of tumor necrosis factor-alpha than did peripheral blood mononuclear cells infected with more virulent nonpassaged strains.

Synthetic-fibre filters for preventing dracunculiasis: 100 versus 200 micrometres pore size.

Filtering of drinking water to remove the copepod intermediate hosts of Dracunculus medinensis is a primary strategy for control of guinea-worm disease. Since filters of different porosities are used, we tested the efficiency of synthetic-fibre filters of 100 microns and 200 microns pore size in removing the various stages of 3 species of copepods from water samples. The 200 microns mesh retained the larger copepodid stages including adults (C III-VI), but permitted passage of smaller copepodids and all naupliar stages. The 100 microns mesh retained all but the earliest naupliar stages (N I-II) which are unlikely to harbour guinea-worm larvae.

Application of the enzyme linked immunosorbent assay (ELISA) for the serodiagnosis of Schistosoma mansoni infections in St. Lucia.

As part of our search for a serodiagnostic assay to replace the expensive and tedious stool examination in the diagnosis of Schistosoma mansoni infection, we have studied the sensitivity, specificity and quantitative features of an enzyme linked immunoassay (ELISA) using crude S. mansoni egg antigen preparation. Results of studies carried out in both London and St. Lucia indicate that the assay can give useful serodiagnostic information ranging from 82 to 99.5% sensitivity, depending on level of infection intensity and method of blood collection and 100% specificity in St. Lucian/St. Vincent populations. The St. Lucia study also showed that the assay could be operated in a qualitative form in an endemic area.

Comparison of ELISA, radioimmunoassay and stool examination for Schistosoma mansoni infection.

A comparison was made of the sensitivity and specificity of four diagnostic tests for Schistosoma mansoni infection in a community of 516 untreated persons in St. Lucia, West Indies. Prevalence of infection as obtained by: (i) the Bell filtration technique was 44.4% (one filter) and 63.2% (three filters); (ii) the Kato thick smear, 60.2%; (iii) by radioimmunoassay (RIA), 73.3%; and (iv) enzyme-immunoassay (ELISA) 70.9%. The age distribution of persons serologically positive but parasitologically negative showed these to be mostly children and persons 40 years old and over. By means of a statistical test due to Cochrane, it was concluded that there was no evidence to indicate a difference between paired serological tests and paired parasitological tests in their diagnostic capability. There was a very significant difference between the Bell technique and the other three tests. The ELISA emerged as a less satisfactory test than the RIA or the Kato thick smear. The levels of sensitivity and specificity of each test were measured by Armitage's "J" index. The reliability of the Bell filtration technique was 64%, of the ELISA 68%, of the RIA 78% and of the Kato 85%.

The diagnosis of old and new gastrointestinal parasites.

For the foreseeable future, light microscopy will continue to be the method of choice for diagnosing gastrointestinal parasites. However, in selected circumstances, the use of commercially available immunofluorescent kits will supersede the use of routine light microscopy for diagnosis of Giardia lamblia and Cryptosporidium parvum. These techniques may used to diagnose invasive amebic infections caused by E. histolytica in the future. Pooling stool samples from the same or even different patients may offer a means to process specimens in a more efficient and cost-effective manner without lowering the predictive value of an ova and parasite examination. Although we suggest that, with some exceptions, stools for ova and parasite examination should not be accepted past the fourth day of hospitalization, we cannot recommend the use of a single stool sample for diagnosis without extensive studies in individual parasitology laboratories. Techniques have still not been developed for the optimum methods of concentration of stool for diagnosis of coccidian infections. For most laboratories, the diagnosis of microsporidian infections remains problematic because of the lack of a commercial source for oocysts to provide positive control material. (Note: There is now a commercial source for oocysts available.)

Phialophora verrucosa-induced subcutaneous phaeohyphomycosis. Fine needle aspiration findings.

A 34-year-old woman on immunosuppressive therapy presented with a subcutaneous, cystic lesion on the dorsum of the right foot. Cytologic examination of material obtained by fine needle aspiration (FNA) revealed a mixture of acute and granulomatous inflammation as well as brown-pigmented fungi in the form of budding yeast, pseudohyphae and septate hyphae. The findings suggested subcutaneous phaeohyphomycosis (phaeomycotic cyst). Culture grew Phialophora verrucosa. The cytologic, histologic and cultural findings are given. This case demonstrates that phaeohyphomycosis can be diagnosed by FNA but that fungal culture is necessary to establish the identity of the etiologic agent. This appears to be the first case of P. verrucosa-induced subcutaneous phaeohyphomycosis reported in the Western Hemisphere.

Attachment of Pneumocystis carinii to rat pneumocytes.

Male Sprague-Dawley rats were immunosuppressed by subcutaneous injections of cortisone acetate for 8 weeks to induce Pneumocystis carinii pneumonia. Rats were killed with ether, their lungs were filled in situ with cold glutaraldehyde, and sections were examined by transmission electron microscopy. P. carinii trophozoites were observed in lungs for as long as 6 weeks after cessation of corticosteroid injections. Trophozoites were attached most frequently to type I pneumocytes but were seen on several occasions to be attached to type II pneumocytes. In attachment, trophozoites in contact with alveolar epithelial cells produced cytoplasmic modifications of three basic forms: one was an invagination of parasite surface to pinch cytoplasmic extensions on the surface of the epithelial cells. A second was an extension that was inserted into a crevice of the host surface and enlarged at the tip to form an anchor. The third was an extension that remained pointed at the tip and was recurved to form a hook. None of these modifications was seen on the surface of the trophozoites. Filopodia did not appear to be involved in attachment but were seen on both attached and lumenal surfaces of the trophozoites. Trophozoites and cysts were also observed to be partially or completely enveloped by extensions of the host cell's cytoplasm. In these instances, parasites had rounded surfaces but appeared viable. No fusion of cell membranes between parasite and host cells was ever seen. These observations may help explain why P. carinii can attach tenaciously to lung epithelium without cell-membrane fusion, production of a glycocalyx, or invasion of host cells.

Comparison of the FeKal CON-Trate system with the formalin-ethyl acetate technique for detection of intestinal parasites.

The ability of the FeKal CON-Trate system (Trend Scientific, Minneapolis, Minn.) to recover parasite ova, cysts, or larvae from 300 fecal specimens was compared with that of the Formalin-ethyl acetate sedimentation technique. One hundred stool samples had previously been determined to contain 129 parasite forms. The FeKal system detected 127 parasites (sensitivity, 98.4%), and the Formalin-ethyl acetate sedimentation technique detected 125 parasites (sensitivity, 96.9%). Higher counts of parasite forms were obtained for 11 of 14 species of parasites in specimens prepared by the FeKal system. Four specimens were negative by the Formalin-ethyl acetate method and two by the FeKal system. These false-negative observations occurred in specimens with low counts of parasites. There were no false-positive results.

Monofilament nylon filters for preventing dracunculiasis: Durability and copepod retention after long term field use in Pakistan.

Filtration of drinking water to remove the cyclopoid copepod intermediate hosts of guinea worm. Dracunculus medinensis, is one of the primary intervention strategies for preventing dracunculiasis. In early 1987, monofilament nylon filters with 200 microns pore size were distributed to households in selected guinea worm-infected villages in Pakistan. The filters proved popular with the villagers, although reports of "loss of filters" could diminish the community-wide effectiveness of this control measure. After 12 to 15 months of usage a sample of these filters was collected and examined for damage or impairment which would decrease their use or their capacity to retain potentially infective copepods. Although all naupliar stages and early copepodids (Stages CI-II) passed through these used filters, the larger copepodids including adults (Stages CIII-VI) were retained despite small tears in the fabric. This field trial showed that after 12 to 15 months of regular use, monofilament nylon filters of 200 microns pore size remained effective in removing copepodid stages capable of supporting development of D. medinensis larvae. Considering the ease of use, popularity and effective filtration of potentially infective copepods following prolonged field use, we recommend that monofilament filters be considered in any program of guinea worm elimination.

Alga associated with diarrhea in patients with acquired immunodeficiency syndrome and in travelers.

Spherical bodies resembling coccidian oocysts and measuring 8.0 to 9.0 microns in diameter were seen in the stools of eight persons with explosive, watery diarrhea. Seven had recently traveled to tropical countries, mostly in the Caribbean, and four had acquired immunodeficiency syndrome. The structures were easily discernible in wet mounts by light microscopy and contained variable numbers of granular inclusions, but were refractory to, or stained partially with, 12 commonly used laboratory stains. Electron microscopy revealed an outer fibrillar coat, a thin cell wall, granules, and organelles which were not surrounded by membranes. One type of organelle was similar to the thylakoid photosynthesizing organelles of blue-green algae (cyanobacteria). These findings indicate that the bodies may be a species of blue-green algae.

Comparative study with in situ hybridization and immunocytochemistry in detection of HIV-1 in formalin-fixed paraffin-embedded cell cultures.

The sensitivities of three immunohistological techniques were compared in this study for detecting human immunodeficiency virus (HIV-1) in infected cultured human lymphocytes that had been formalin-fixed and paraffin-embedded. The techniques included in situ hybridization (ISH) with HIV-1 cDNA; immunocytochemistry with HIV-1 p24 monoclonal antibody (ICC-m); and immunocytochemistry with HIV-1 polyclonal antibody from a patient with acquired immunodeficiency syndrome (AIDS) (ICC-p). Procedures were optimized for enzyme digestion and for antibody reaction conditions. HIV-1--infected cells and noninfected control cells were tested. Noninfected controls were uniformally negative by all three methods. Infected cells had the highest positivity rate by the ISH method (p less than or equal to 0.0001), and the ICC-p method was more positive than the ICC-m (p less than or equal to 0.0001). Both the ICC-p and the ICC-m techniques were more positive with the cocultivated cell cultures than the ISH, which was more sensitive with the infected continuous cell line (P less than or equal to 0.0001). The ICC-p method had a lower standard deviation on positive results than either the ICC-m or ISH method. The variability observed with these test procedures, reagents, and specimens suggests that these are important technological parameters in detecting p24, with implications for detecting other HIV-1 markers in infected tissues.

A tissue culture bilayer model to study the passage of Neisseria meningitidis.

A tissue culture bilayer system has been developed as a model to study the mechanisms of attachment and invasion involved in the pathogenesis of Neisseria meningitidis. The model incorporates epithelial and endothelial cell layers separated by a microporous membrane and makes it possible to observe and quantify the passage of bacteria through the multiple layers and to study the mechanisms by which they make this passage. This model is adaptable to a wide variety of microbial pathogens and can be modified by substituting any physiologically relevant eucaryotic cells for the component layers. The system's makeup of cells of human origin and its reproducibility give it advantages over animal and primary organ culture models, while the added complexity of multiple layers allowing cell-to-cell communication makes it a more realistic human tissue model than standard cell monolayers.

Recovery of Cyclospora organisms from patients with prolonged diarrhea.

A newly recognized protozoan human parasite, Cyclospora has been incriminated as the cause of prolonged diarrhea. Five patients had episodes of diarrhea accompanied by nausea, weight loss, and/or low-grade fever for 10-45 days. Multiple fecal samples fixed in sodium acetate-acetic acid-formalin contained spherical organisms measuring 8-10 microns in diameter; a modified concentration technique was used to detect them. The sediment was examined by direct microscopy and autofluorescence, and the identification was confirmed by acid-fast stain. All patients had visited either Mexico or Thailand. The presence of Cyclospora organisms in these patients shows that these can be etiologic agents of traveler's diarrhea in both immunocompetent and immunocompromised hosts. Fecal specimens from patients with unexplained diarrhea should be routinely examined for their presence.