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D M Thea

Publications and source records attributed to D M Thea.

2 recordsLinked to original sources

Persistent diarrhea associated with AIDS.

Chronic diarrhea and wasting are very common manifestations of AIDS in adults in developing countries. Etiologic studies show that protozoa (including Cryptosporidium parvum, Isospora belli, and Enterocytozoon bieniusi) and Mycobacterium avium-intracellulara are the most frequently identified pathogens. Limited data in children suggest that common enteric pathogens are equally as likely in HIV+ and HIV- babies. Preliminary analysis of an ongoing longitudinal study of 469 babies born to mothers with known HIV serostatus in Kinshasa, Zaire, reveals progression of acute to persistent diarrhea is six times greater in HIV+ compared to HIV- babies, and 3.5 times greater in HIV- babies born of HIV+ mothers in comparison to HIV- babies with HIV- mothers. HIV+ babies were also at greater risk than HIV- babies to have recurrent episodes of diarrhea (RR = 2.3). Fifty percent of the deaths were due to acute or persistent diarrhea, and were strongly associated with HIV infection. Efforts to improve child survival in AIDS infected populations will need to address HIV infections in both mothers and infants.

Acquired Immunodeficiency Syndrome

Identification and partial purification of a lectin on the surface of the sporozoite of Cryptosporidium parvum.

A human-derived isolate of Cryptosporidium parvum from a symptomatic patient with the acquired immunodeficiency syndrome was expanded in vivo by infecting a neonatal calf with 10(8) oocysts. Sporozoites were isolated from 4 x 10(10) oocysts harvested from this single infection, and the characteristics of mixed hemagglutination (HA) with rabbit erythrocytes were determined. Sporozoite HA was inhibited by bovine submaxillary mucin (BSM), hog gastric mucin, and orosomucoid, but not by simple sugars, including sialic acid. Carbohydrate-inhibitable HA (lectin) activity increased with sporozoite lysis and was associated with the sporozoite membrane fractions. The ability of intact sporozoites to form rosettes around erythrocytes indicates that the HA (lectin) is, at least in part, present on the parasite surface. Hemagglutination (lectin) activity was partially purified from sporozoite lysates by affinity chromatography with BSM coupled to Sepharose-4B. Best elution was obtained with ethylene glycol and NaCl, which resulted in enrichment of 6 bands compared to the crude starting lysate (Mr = 60, 24, 22, 20, and 15 kDa and a 40-kDa doublet). Our results indicate that an HA (lectin) activity is present on the surface of intact sporozoites where it could play a role in cell-to-cell interactions with eukaryotic targets.

Acquired Immunodeficiency Syndrome