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.

A quantitative ultrastructural study of the liver and the spleen in fatal falciparum malaria.

We performed a retrospective study of 25 patients who died of severe falciparum malaria in Thailand and Vietnam using electron microscopy. The aims of the study were: to determine if there was any significant association between parasitized red blood cells (PRBC) sequestered in liver and spleen and particular pre-mortem clinical complications, and to compare the degree of parasite load between the liver and spleen within the same patients. PRBC sequestrations in each organ were compared with the pre-mortem parasitemia, to calculate the sequestration index (S.I.). The S.I. showed that the degree of PRBC sequestration in the spleen was higher than the liver (S.I. median = 3.13, 0.87, respectively) (p < 0.05). The results of quantitative ultrastructural study showed a significantly high parasite load in the liver of patients with jaundice, hepatomegaly and liver enzyme elevation (p < 0.05). We found a significant correlation between PRBC sequestration in the liver and a high serum bilirubin level, a high aspartate aminotransferase (AST) level and an increase in the size of the liver (Spearman's correlation coefficient = 0.688, 0.572, 0.736, respectively). Furthermore, a higher parasite load was found in the liver of patients with acute renal failure (ARF) compared to patients without ARF (p < 0.05). These findings suggest that PRBC sequestration in the liver is quantitatively associated with pre-mortem hepatic dysfunction and renal impairment. There was no significant difference between splenomegaly and PRBC sequestration. The size of a palpable spleen was not correlated with parasite load in the spleen. When ultrastructural features were compared between the two reticuloendothelial organs, we found that the spleen had more PRBC and phagocytes than the liver. The spleen of non-cerebral malaria (NCM) patients had more phagocytes than cerebral malaria (CM) patients. This observation reveals that the spleen plays a major role in malaria parasite clearance, and is associated with host defence mechanisms against malaria.

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.