High prevalence of Microsporidium infection in HIV-infected patients.

Sixty-four patients infected with human immunodeficiency virus (HIV) participated in a study to determine opportunistic enteric pathogens and compare them with the patients' clinical status. The most frequently found pathogens were microsporidium (81.2%), Cryptosporidium parvum (20.3%), Candida albicans (12.5%) and Blastocystis hominis (10.9%). Less frequently found pathogens were Giardia intestinalis (6.2%), Cyclospora (4.7%), Opishorchis viverrini ova (3.1%), Strongyloides stercoralis larvae (3.1%) and hookworm ova (1.6%). The presence of enteric pathogens was not significantly associated with sex, length of HIV seropositivity and diarrheal symptoms. A high prevalence of microsporidium, based on microscopic examination, was found in Thai HIV-infected patients. This confirms the importance of microsporidium in HIV-infected/AIDS patients and the necessity for stool evaluation in all HIV-infected patients.

Early detection and identification of amphizoic amoebae from nasal exudates of a symptomatic case.

A man visited the Out Patient Department of the hospital for Tropical Diseases in February 2004 with low grade fever and severe headache for a week. He had the history of diving in a natural pond 2-3 days before the onset of the disease. A thick bloody mucous was observed from the nasal discharge. Fresh microscopic observation of the exudates in 0.85% sodium chloride revealed numerous active amoeba trophozoites. Two groups of the trophozoites were observed The first group was 10 micro sized amoeba with active directional movement by lobopodia and the second group was 15-30 micro sized amoeba with active multiprogressive movement by filopodia. Few flagellate forms were observed after exflagellation in distilled water and some polygonal cysts were also found. Giemsa' stain was used to differentiate the amoeba trophozoites from the leukocytes. It was concluded that this patient was infected by both Naegleria spp. and Acanthamoeba spp. This is the first report of double infection of free-living amoeba in a symptomatic and non-fatal patient.

Development of Isospora belli in Hct-8, Hep-2, human fibroblast, BEK and Vero culture cells.

The development of Isospora belli, a human coccidian parasite, was studied in different cell lines. Merozoites were observed in all kinds of cells, whereas sporogony was demonstrated only in Hct-8. This implied that not only the human cell line can be infected, but also some animal cell lines. Unizoites could be found in Vero cells. The merozoites were transferred to a new culture cell for three passages and maintained for two weeks, but no oocyst production was observed in any culture cells during cultivation.

Comparison of Cryptosporidium parvum development in various cell lines for screening in vitro drug testing.

This study describes the development of Cryptosporidium parvum in MDCK, MA-104, Hep-2 and Vero cell lines. Differences in susceptibility, infectivity, and the methodology of excystation were determined. Various solutions were considered to determine the factors which enhanced the excystation (eg with and without sodium hypochlorite, trypsin or sodium taurocholate). It was shown that the sporozoites could be excysted in media either with or without trypsin and sodium taurocholate, but the number of sporozoites in the latter solution was less than the former one. Only oocysts digested by sodium hypochlorite and trypsin can enter the culture cells. Numerous meronts and oocysts were demonstrated and persisted for 9 days. Asexual stages were not observed in MA-104. Only few oocysts could be detected 1-3 days post-inoculation. There was a significant difference between the number of oocysts, which invaded MDCK, MA-104, and Hep-2 cells. MDCK gave the highest susceptibility to oocyst invasion among the three cell lines and asexual stages were also found. Among the 25 isolates, which had been cultivated, 23 isolates could infect MDCK and Hep-2. Only 2 isolates could not infect the MDCK cell. These 2 isolates could infect the Vero cell and yielded high numbers of trophozoites. Praziquantel (PZQ), doxycycline, and paromomycin (PRM) were tested on the infecting parasites. The drugs were added either with the inoculum or 24 hours after inoculation. None of them was effective, including PRM, which had been previously reported as effective.

Case report: intraocular gnathostomiasis in Vietnam.

This is the report of the first case of intraocular gnathostomiasis diagnosed in Vietnam. The disease progressed in two months in two distinct phases: in the first phase, the patient had swellings, which appeared at different times and in different locations, on his face--this phase lasted around one month; the second phase was the embedding of the parasite in the vitreous cavity of the right eye and uveitis. Surgical extraction of a living Gnathostoma larva was carried out. Based on morphological, histological criteria, the larva may have been an atypical third-stage of Gnathostoma spinigerum.

Necropsy in HIV-infected patients.

Human immunodeficiency virus (HIV)infection is usually followed by opportunistic infections, especially in the full-blown acquired immunodeficiency syndrome (AIDS). This study details the histopathological changes of different organs in relation to HIV infection, with particular emphasis on the opportunistic infections. Various organs from seventeen HIV-infected patients were collected by necropsy and analyzed for histopathological changes. The major histopathological changes included cytomegalovirus infection, cryptococcosis, penicilliosis, bacterial pneumonia, cryptosporidiosis, pneumocystosis, candidiasis, tuberculosis, granulomatosis of unknown etiology, early cirrhosis and chronic active hepatitis. General organ changes from seventeen cases of HIV-infected patients were described and discussed.