Persistent diarrhoea in Zairian AIDS patients: an endoscopic and histological study

Cryptococcosis in the Democratic Republic of Congo from 1953 to 2021: a systematic review and meta-analysis

Cryptococcosis is a common opportunistic infection associated with HIV/AIDS. The present review systematically describes the clinical and biological aspects of cryptococcosis in the Democratic Republic of Congo (DRC) and estimates its 2020 burden in people living with HIV (PLHIV). Following PRISMA guidelines, we searched online databases for records of cryptococcosis/Cryptococcus spp. in the DRC. Meta-analysis was then performed to estimate summary statistics and the corresponding 95% confidence intervals (CI). A total of 30 studies were included. These included 1,018 cryptococcosis patients, including 80.8% with NMC and predominantly immunocompromised due to HIV/AIDS (97.6%). The NMC mean prevalence was estimated at 9.63% (95% CI: 5.99-14.07). More than one in two patients (52.7%) under treatment died. Monotherapy with fluconazole was the main treatment administered (80.6%). Furthermore, we estimate that about 9,265 (95% CI: 5,763-13,537) PLHIV had cryptococcosis in 2020, in DRC; of which about 4,883 (95% CI: 3,037-7,134) would have died in the same year. Among isolates in all included studies, 74 strains have been characterized. Of these, 82.4% concerned Cryptococcus neoformans sensu lato (s.l) (exclusively of serotype A and mostly of molecular types VNI and VNII) and 17.6% concerned Cryptotoccus gattii s.l (belonging to serotype B and molecular type VGI). Cryptococcosis remains common with an unacceptably high mortality rate. A large number of PLHIV affected by and dying from cryptococcosis in 2020 demonstrates its heavy burden among the Congolese PLHIV. To mitigate this burden, it is important to improve the quality and accessibility of care for all PLHIV.

Serious fungal diseases in Democratic Republic of Congo - Incidence and prevalence estimates

A literature review was conducted to assess the burden of serious fungal infections in the Democratic Republic of the Congo (DRC) (population 95,326,000). English and French publications were listed and analysed using PubMed/Medline, Google Scholar and the African Journals database. Publication dates spanning 1943-2020 were included in the scope of the review. From the analysis of published articles, we estimate a total of about 5,177,000 people (5.4%) suffer from serious fungal infections in the DRC annually. The incidence of cryptococcal meningitis, Pneumocystis jirovecii pneumonia in adults and invasive aspergillosis in AIDS patients was estimated at 6168, 2800 and 380 cases per year. Oral and oesophageal candidiasis represent 50,470 and 28,800 HIV-infected patients respectively. Chronic pulmonary aspergillosis post-tuberculosis incidence and prevalence was estimated to be 54,700. Fungal asthma (allergic bronchopulmonary aspergillosis and severe asthma with fungal sensitization) probably has a prevalence of 88,800 and 117,200. The estimated prevalence of recurrent vulvovaginal candidiasis and tinea capitis is 1,202,640 and 3,551,900 respectively.Further work is required to provide additional studies on opportunistic infections for improving diagnosis and the implementation of a national surveillance programme of fungal disease in the DRC.

Cystoisospora belli infections in humans: the past 100 years

Cystoisospora belli is a coccidian parasite of humans, with a direct fecal-oral transmission cycle. It is globally distributed, but mainly found in tropical and subtropical areas. Many cases of C. belli infections have been reported in patients with HIV, and in patients undergoing immunosuppressive therapy for organ transplants or those treated for tumours worldwide. Unsporulated or partially sporulated oocysts of C. belli are excreted in feces. When sporulated oocysts in contaminated water or food are ingested, asexual and sexual stages of C. belli are confined to the epithelium of intestines, bile ducts and gallbladder. Monozoic tissue cysts are present in extra-intestinal organs (lamina propria of the small and large intestine, lymph nodes, spleen, and liver) of immunosuppressed humans. However, a paratenic host has not been demonstrated. Cystoisospora belli infections can be persistent, lasting for months, and relapses are common; the mechanism of relapse is unknown. Recently, the endogenous stages of C. belli were re-examined and attention was drawn to cases of misidentification of non-protozoal structures in the gallbladder of patients as C. belli. Here, we review all aspects of the biology of C. belli, including morphology, endogenous stages, prevalence, epidemiology, symptoms, diagnosis and control.

Prevalence of Cryptosporidium, microsporidia and Isospora infection in HIV-infected people: a global systematic review and meta-analysis

BACKGROUND

Diarrhea caused by opportunistic intestinal protozoa is a common problem in HIV infection. We aimed to establish the prevalence of Cryptosporidium, misrosporidia, and Isospora in HIV-infected people using a systematic review and meta-analysis, which is central to developing public policy and clinical services.

METHODS

We searched PubMed, ScienceDirect, Google Scholar, Embase, Chinese Web of Knowledge, Wanfang, and Chongqing VIP databases for studies reporting Cryptosporidium, microsporidia, or Isospora infection in HIV-infected people. We extracted the numbers of people with HIV and protozoa infection, and estimated the pooled prevalence of parasite infection by a random effects model.

RESULTS

Our research identified 131 studies that reported Cryptosporidium, microsporidia, and Isospora infection in HIV-infected people. We estimated the pooled prevalence to be 14.0% (3283/43,218; 95% CI: 13.0-15.0%) for Cryptosporidium, 11.8% (1090/18,006; 95% CI: 10.1-13.4%) for microsporidia, and 2.5% (788/105,922; 95% CI: 2.1-2.9%) for Isospora. A low prevalence of microsporidia and Isospora infection was found in high-income countries, and a high prevalence of Cryptosporidium and Isospora infection was found in sub-Saharan Africa. We also detected a high prevalence of Cryptosporidium, microsporidia, and Isospora infection in patients with diarrhea. Sensitivity analysis showed that three studies significantly affect the prevalence of Isospora, which was adjusted to 5.0% (469/8570; 95% CI: 4.1-5.9%) by excluding these studies.

CONCLUSIONS

Our findings suggest that HIV-infected people have a high prevalence of Cryptosporidium, microsporidia, and Isospora infection in low-income countries and patients with diarrhea, especially in sub-Saharan Africa, reinforcing the importance of routine surveillance for opportunistic intestinal protozoa in HIV-infected people.

Intestinal tract and acquired immunodeficiency syndrome

The intestinal tract is closely associated with the transmission, disease progression and the prevention and control of acquired immune deficiency syndrome (AIDS). It has been noticed early in AIDS research that a large percent of AIDS patients presented abnormalities in their intestinal tract, such as diarrhea. Now it is known that the intestinal tract has close and complex relationships with AIDS: (1) the intestinal tract is directly involved in the transmission of human immunodeficiency virus-1 (HIV-1); (2) the damage of the intestinal barrier of HIV/AIDS patients directly promotes AIDS disease progression; and (3) most importantly, the intestinal tract is an important target for the treatment and prevention of HIV/AIDS. The author has previously reviewed the progress in understanding the roles of the intestinal tract in HIV-1 infection and the changes of the intestinal tract after HIV-1 infection. In the current review, I discuss the progress in understanding the roles of the damage of the intestinal mucosal immune system in AIDS disease progression, and the potential application value of the restoration of intestinal mucosal immunity in the treatment of AIDS.

Epidemiology and molecular characterization of Cryptosporidium spp. in humans, wild primates, and domesticated animals in the Greater Gombe Ecosystem, Tanzania

Cryptosporidium is an important zoonotic parasite globally. Few studies have examined the ecology and epidemiology of this pathogen in rural tropical systems characterized by high rates of overlap among humans, domesticated animals, and wildlife. We investigated risk factors for Cryptosporidium infection and assessed cross-species transmission potential among people, non-human primates, and domestic animals in the Gombe Ecosystem, Kigoma District, Tanzania. A cross-sectional survey was designed to determine the occurrence and risk factors for Cryptosporidium infection in humans, domestic animals and wildlife living in and around Gombe National Park. Diagnostic PCR revealed Cryptosporidium infection rates of 4.3% in humans, 16.0% in non-human primates, and 9.6% in livestock. Local streams sampled were negative. DNA sequencing uncovered a complex epidemiology for Cryptosporidium in this system, with humans, baboons and a subset of chimpanzees infected with C. hominis subtype IfA12G2; another subset of chimpanzees infected with C. suis; and all positive goats and sheep infected with C. xiaoi. For humans, residence location was associated with increased risk of infection in Mwamgongo village compared to one camp (Kasekela), and there was an increased odds for infection when living in a household with another positive person. Fecal consistency and other gastrointestinal signs did not predict Cryptosporidium infection. Despite a high degree of habitat overlap between village people and livestock, our results suggest that there are distinct Cryptosporidium transmission dynamics for humans and livestock in this system. The dominance of C. hominis subtype IfA12G2 among humans and non-human primates suggest cross-species transmission. Interestingly, a subset of chimpanzees was infected with C. suis. We hypothesize that there is cross-species transmission from bush pigs (Potaochoerus larvatus) to chimpanzees in Gombe forest, since domesticated pigs are regionally absent. Our findings demonstrate a complex nature of Cryptosporidium in sympatric primates, including humans, and stress the need for further studies.

Cryptosporidium is a common zoonotic gastrointestinal parasite. In a cross-sectional survey of humans, non-human primates (chimpanzees and baboons) and livestock in the Greater Gombe Ecosystem, Tanzania, Cryptosporidium infection rate was 4.3%, 16.0% and 9.6% respectively. Infection was not associated with clinical disease in people; however, living in a household with an infected person increased one’s risk of infection. Phylogenetic analyses identified clusters of Cryptosporidium with a mixed host background. Surprisingly, the Mitumba chimpanzee community, which shares a natural boundary with a human community, had a lower occurrence of C. hominis compared to the Kasakela chimpanzee community, which resides in the forest interior (less human exposure). However, Kasakela chimpanzees were also infected with C. suis, suggesting a transmission cycle linked to sympatric bush pigs. Our findings highlight the complex nature of zoonotic parasite transmission and stress the need for further studies in similar systems.

Prevalence of Cryptosporidium species among HIV positive asymptomatic and symptomatic immigrant population in Kashmir, India

BACKGROUND AND OBJECTIVES

Cryptosporidiosis has not been reported as an endemic disease in Kashmir, but high prevalence of Cryptosporidium sp. has been found among asymptomatic (non-diarrheic) HIV positive immigrants in present study. Due to increasing number of HIV positive immigrants in Kashmir, Cryptosporidium may become a public health problem in Kashmir.

MATERIALS AND METHODS

A total of 45 stool samples were obtained from symptomatic (diarrheic n = 9) and asymptomatic (non-diarrheic n = 36) patients infected with HIV. The stool samples were concentrated using formalin ethyl acetate concentration technique, stained with modified Kinyoun's cold stain and oocysts were identified by microscopy under 1000 x magnification. It was confirmed by detection of antigens in stool samples by ELISA.

RESULTS

It was established that all the patients studied were carriers of Cryptosporidium. In present study though 80% of patients were asymptomatic (non-diarrheic) and HIV positive which involved non-Kashmiri army personals and travelers (immigrants) but were carriers of Cryptosporidium and 20% of HIV positive patients were emigrants (local Kashmiri traders) who travelled different states of India were having diarrhea (symptomatic) as well as carrier of Cryptosporidium.

CONCLUSION

Though Cryptosporidium infection causes chronic diarrhea but in present study all HIV positive patients screened whether diarrheic or non-diarrheic were positive for Cryptosporidium. To prevent the transmission of Cryptosporidium oocyst in environment and endemic spread of cryptosporidiosis as non-diarrheic HIV positive population may be potential source of infection, obligatory laboratory testing for Cryptosporidium in HIV positive immigrant population like traders and travelers is highly recommended in order to have a better understanding of the cause of spread Cryptosporidium infection in Kashmir.

Opportunistic and other intestinal parasites among HIV/AIDS patients attending Gambi higher clinic in Bahir Dar city, North West Ethiopia

OBJECTIVE

To determine the magnitude of opportunistic and non-opportunistic intestinal parasitic infections among HIV/AIDS patients in Bahir Dar.

METHODS

Cross-sectional study was conducted among HIV/AIDS patients attending Gambi higher clinic from April1-May 30, 2009. Convenient sampling technique was employed to identify the study subjects and hence a total of 248 subjects were included. A pre-tested structured questionnaire was used to collect socio-demographic data of patients. Stool samples were examined by direct saline, iodine wet mount, formol-ether sedimentation concentration and modified Ziehl-Neelsen staining technique.

RESULTS

Out of 248 enrolled in the study, 171(69.0%) (90 males and 81 females) were infected with one or more intestinal parasites. The highest rate of intestinal parasites were observed among HIV/AIDS patients (80.3%, 151/188), and the infection rate of HIV negative individuals was 33.3% (20/60). Cryptosporidum parvum (43.6%), Isospora belli (15.5%) and Blastocystis hominis (10.5%) were opportunistic parasites that were found only in HIV/AIDS patients.

CONCLUSIONS

Opportunistic parasite infections are common health problem among HIV/AIDS patients in the study area. Therefore, early detection and treatment of these parasites are important to improve the quality of life of HIV/AIDS patients.

Cryptosporidiosis in rhesus macaques challenged during acute and chronic phases of SIV infection

The intestinal immune dysfunction due to loss of mucosal and peripheral CD4(+) T cells in individuals with HIV/AIDS is presumably responsible for the establishment of persistent cryptosporidiosis. Simian immunodeficiency virus (SIV)-infected macaques were used to investigate the phase/timing in SIV infection, which permits a self-limiting Cryptosporidium parvum infection to become persistent in immunodeficient hosts because of significant mucosal immune defects. Two groups of SIV-infected macaques were challenged with C. parvum; one was challenged during the acute SIV infection phase (2 weeks post-SIV infection) and the second was challenged during the chronic SIV phase (CD4 counts 200-500 cells/μl of blood). Samples (fecal, blood, biopsy, and necropsy) were collected at different time points after infection to correlate the progression of disease with the immune status of the animals. All seven SIV-infected macaques challenged during the acute phase of SIV infection became persistently infected and excreted oocysts for 1-4 months. However, four of the six in the chronic SIV phase became infected with cryptosporidiosis, of which one survived 2 weeks and one became naturally infected. Sequential analysis of CD4(+) in blood and intestines of coinfected macaques exhibited pronounced losses of CD4 T cells during the first 2 weeks after SIV infection, followed by transient rebound of CD4 T cells in the gut after C. parvum infection, and then a gradual loss over subsequent months. Persistent cryptosporidiosis was more consistently induced during the acute SIV phase indicating that profound viral damage to gut lymphoid tissue during the acute phase was more conducive, compared with the chronic phase, to establishing persistent cryptosporidiosis than low circulating CD4 T cells.

Review article: the aetiology, investigation and management of diarrhoea in the HIV-positive patient

BACKGROUND

Diarrhoea is a common presentation throughout the course of HIV disease.

AIM

To review the literature relating to aetiology, investigation and management of diarrhoea in the HIV-infected adult.

METHODS

The PubMed database was searched using major subject headings 'AIDS' or 'HIV' and 'diarrhoea' or 'intestinal parasite'. The search was limited to adults and to studies with >10 patients.

RESULTS

Diarrhoea affects 40-80% of HIV-infected adults untreated with antiretroviral therapy (ART). First-line investigation is by stool microbiology. Reported yield varies with geography and methodology. Molecular and immunological methods and special stains have improved diagnostic yield. Endoscopy is diagnostic in 30-70% of cases of pathogen-negative diarrhoea and evidence supports flexible sigmoidoscopy as a first line screening procedure (80-95% sensitive for CMV colitis), followed by colonoscopy and terminal ileoscopy. Radiology is useful to assess severity, distribution, complications and to diagnose HIV-related malignancies. Side effects and compliance with ART are important considerations in assessment. There is a good evidence base for many specific therapies, but optimal treatment of cryptosporidiosis is unclear and only limited data support symptomatic treatments.

CONCLUSIONS

The immunological response to HIV infection and Antiretroviral therapy remains incompletely understood. Antiretroviral therapy regimens need to be optimised to suppress HIV while minimising side effects. Effective agents for management of cryptosporidiosis are lacking. There is an urgent need for enhanced regional diagnostic facilities in countries with a high prevalence of HIV. The ongoing roll-out of Antiretroviral therapy in low-resource settings will continue to change the aetiology and management of this problem, necessitating ongoing surveillance and study.

Enteric Pathogens in HIV/AIDS from a Tertiary Care Hospital

BACKGROUND

Patterns of enteric infections in HIV in developing countries may differ in several important ways from developed countries, the knowledge of which can often guide therapy when resource limitations hamper the exact diagnosis of the etiological agent in HIV-associated diarrhea.

OBJECTIVES

The primary objective of this study was to define and compare the microbial etiologies of diarrhea in HIV-1 infected and non infected patients and in HIV infected non diarrheal patients.

MATERIALS AND METHODS

This study was conducted between April 2007 and July 2007 at the Department of Microbiology, Maulana Azad Medical College, New Delhi. Stool samples from 50 HIV seropositive cases with diarrhea (study group), 50 HIV seropositive cases without diarrhea (control group I), and 50 HIV seronegative cases with diarrhea (control group II) were examined. After the diagnosis of HIV infection was made, routine parasitological and bacteriological detection was done. An ELISA was used for the detection of Clostridium difficile toxin and Cryptosporidium antigen in stool samples.

RESULTS

The overall prevalence of enteric parasitosis in the study group was 20% and the bacteria identified were Escherischia coli in 24% of the case, Clostridium difficile in 10% of the cases, Salmonella species and Vibrio cholerae in 4% of the cases, and Shigella species in 2% of the cases. Candida species was identified in 36% of the cases.

CONCLUSIONS

Identification of the etiological agent of diarrhea in a patient with AIDS is very important as it can help in the institution of appropriate therapy and the reduction of morbidity and mortality in these patients.

Tropical malabsorption

Malabsorption is an important clinical problem both in visitors to the tropics and in native residents of tropical countries. Infections of the small intestine are the most important cause of tropical malabsorption. Protozoal infections cause malabsorption in immunocompetent hosts, but do so more commonly in the setting of immune deficiency. Helminth infections occasionally cause malabsorption or protein-losing enteropathy. Intestinal tuberculosis, chronic pancreatitis and small-bowel bacterial overgrowth are important causes of tropical malabsorption. In recent years, inflammatory bowel disease and coeliac disease have become major causes of malabsorption in the tropics. Sporadic tropical sprue is still an important cause of malabsorption in adults and in children in South Asia. Investigations to exclude specific infective, immunological or inflammatory causes are important before considering tropical sprue as a diagnosis. This article briefly reviews the management of tropical sprue and presents an algorithm for its investigation and management.

Etiology of chronic diarrhea in antiretroviral-naive patients with HIV infection admitted to Norodom Sihanouk Hospital, Phnom Penh, Cambodia

BACKGROUND

Although both human immunodeficiency virus (HIV) infection and diarrhea are considerable problems in Cambodia, there have not been any studies to determine the history, clinical presentation, and etiology of chronic diarrhea in patients with HIV infection in Cambodia. In this article, we present a case-control study involving 40 HIV-infected patients with chronic diarrhea and 40 HIV-infected patients without diarrhea.

METHODS

Clinical, demographic, and laboratory data were collected. Stool samples were examined for parasites, including Cryptosporidium species (by partial acid-fast stain), bacterial pathogens, and rotavirus. Samples from 10 case patients and 10 control subjects were also analyzed for Cryptosporidium species by polymerase chain reaction-restriction fragment-length polymorphism.

RESULTS

The median CD4(+) cell count was 11.5 cells/mm(3). A potential pathogen was found in 30 case patients (75%) and 29 control subjects (72.5%). Cryptosporidium was the most common pathogen, present in 16 case patients (40%) and 20 control subjects (53.3%). The presence of Cryptosporidium was confirmed by polymerase chain reaction-restriction fragment-length polymorphism, with a prevalence of 40% in each of the 2 groups of 10 subjects who were enrolled for Cryptosporidium evaluation.

CONCLUSIONS

Subjects in this cohort had severe immunosuppression. The prevalence of pathogens, including Cryptosporidium, was extremely high but did not differ significantly between the case patients with diarrhea and the control subjects without diarrhea. Further studies are needed to examine factors associated with Cryptosporidium carriage and the natural history of asymptomatic infection.

Prevalence of Intestinal Parasites In HIV-Positive/AIDS Patients

The aim of this study was to assess the prevalence of intestinal parasites among HIV-positive/AIDS patients. A control group comprising 30 apparently healthy HIV-negative individuals was included. Of the 60 samples collected from the patients and examined, 34 (56.7%) presented with diarrhoea, while 26 (43.3%) had no reported cases of diarrhoea at the time of study. Seventeen (50%) of the parasites detected in the 34 patients (those with history of diarrhoea) were diarrhoea-related causative agents. However, 17 (50%) of the parasites detected were not diarrhoea-related causative agents. In relation to diarrhoea, Cryptosporidium parvum had the highest prevalence (10%), followed by Giardia intestinalis (8.3%), Entamoeba histolytica (6.7%), Isospora belli (3.3%) and Blastocystis hominis (3.3%) in that order. This study showed a significant prevalence (P<0.05) of intestinal parasites in HIV-positive/AIDS patient. Also, the prevalence of intestinal parasites was higher (P<0.05) in HIV-positive/AIDS patients than in HIV-negative subjects. Although the study is limited in scope, however, it does reflect the importance of evaluating the prevalence of intestinal parasites in HIV-positive/AIDS patients especially at the local level where antiretroviral therapy is not available. The results of this study thus provide vital information for health professionals who are managing these patients. This could lead to improvement in patients' management and care.

HIV, 'an evolving species'. Roles of cellular activation and co-infections

Each small variation of the genome of a species can be preserved if it is useful for the survival of the species in a given environment. Within this framework, the finality of the biological cycle of HIV consists in a search for harmony (biological coherence) with man, which is to say a stable condition. Cellular activation appears to be the strategy developed by HIV in order to achieve this coherence. The price of this strategy is the AIDS. The first contact between HIV and immune system appears to determine the subsequent clinical outcome and the future of HIV. Lymphocytic activation varies during the course of the vital cycle of HIV. For each individual, this lymphocytic activation depends on both the HLA repertoire acquired during thymic ontogenesis and the antigenic experience before and after HIV infection. Thus intercurrent infections alter the immune condition of the organism and influence the outcome of HIV. We described a synthetic analysis of the effects of HIV on the surface protein expression and the cellular activation pathways which should provide insights in the evolutionary relationship between HIV and man and should permit to do a more physiological therapeutic approach.

Chronic diarrhoea caused by Cryptococcus neoformans in a non-human immunodeficiency virus-infected patient

A 43-y-old woman with underlying cervix carcinoma stage IIIB, status postirradiation, and diabetes mellitus with tripathy suffered from chronic diarrhoea for more than 6 months. Stool examination showed few white blood cells and red blood cells. Rectal swab cultures disclosed Cryptococcus neoformans in 2 samples obtained 2 weeks apart. The diarrhoea responded to treatment with oral fluconazole for 4 weeks. Repeated rectal swabs revealed no yeast growth. During follow-up for 4 y, she had no problems with diarrhoea. Chronic diarrhoea caused by C. neoformans is rare and clinical suspicion is needed.

Supernatants of HIV-infected immune cells affect the barrier function of human HT-29/B6 intestinal epithelial cells

OBJECTIVES

Characterization of the diarrhoea-inducing effect of altered cytokine production in HIV infection.

METHODS

Monocyte-derived macrophages (MDM) were infected with macrophagetropic (SF162) and lymphocytotropic (IIIB) HIV-1 strains and cocultured with autologous peripheral blood mononuclear cells (PBMC). After 24 h the supernatants were collected and tested for their immunoreactive levels of cytokines by enzyme-linked immunosorbent assay. The effects of the supernatants and the respective recombinant human cytokines on barrier function of HT-29/B6 cells were determined.

RESULTS

Infection of MDM with HIV-1 SF162 or IIIB led to increased production of tumour necrosis factor-alpha (TNFalpha), interleukin-1-beta, interferon-alpha and interferon-gamma after cell-cell contact with PBMC. Supernatants of infected cells decreased transepithelial resistance (R(t)), with higher effects on R(t) in HIV IIIB infection, which was due to higher cytokine concentrations. The effect was not due to cytotoxicity (negative LDH assay) or epithelial monolayer disruption [zonula occludens protein-1 (ZO-1) immunofluorescence staining]. The effect of HIV-1 IIIB coculture supernatants could be mimicked by the respective recombinant human cytokines. TNFalpha is an effector cytokine, because inhibition of TNFalpha by its soluble receptor decreased the effect of the supernatants on transepithelial resistance. Conductance scanning indicated the cytokine-induced barrier defect to be due to both, induction of epithelial apoptoses and tight junction alterations.

CONCLUSIONS

Cell-cell interaction of HIV-infected macrophages with PBMC leads to a release of cytokines sufficient to alter intestinal epithelial barrier function. The main effect was mediated by TNFalpha inducing a leak-flux which may contribute to the diarrhoea by HIV per se (HIV-enteropathy).

Albendazole chemotherapy for AIDS-related diarrhoea in Zambia--clinical, parasitological and mucosal responses

BACKGROUND

Albendazole reduces diarrhoea in African AIDS patients, but it is unclear if the clinical response to treatment reflects pathogen eradication and/or mucosal recovery.

METHODS

Adults with HIV-related persistent diarrhoea were treated with albendazole 800 mg twice daily for 14 days. Clearance of parasites was evaluated at 3 and 6 weeks by stool microscopy. At baseline and at 6 weeks duodenal biopsies were taken for electron microscopy (EM) and morphometry.

RESULTS

Ten (7%) of 153 patients had cryptosporidiosis, 54 (37%) had isosporiasis and 23 (16%) had microsporidiosis. By 3 weeks, these protozoa were cleared in 27 (46%) of 59 patients initially positive. By 6 weeks, 34 (39%) of 87 patients experienced complete clinical response, 18 (21%) partial response and 35 (40%) no response. Crypt depth increased by 15% over 6 weeks (P < 0.001), but villous height increased only in patients with complete response (median + 50 microm, interquartile range (IQR) 2-90, compared to patients with partial (+ 4 microm, IQR -15,41) or no response (-13 microm, IQR -2,12; P=0.008)). Fifteen patients died: body mass index < 17.5 kg/m(2) and crypt depth < 180 microm independently predicted death.

CONCLUSIONS

Albendazole therapy reduced the burden of protozoal infection and promoted mucosal recovery in patients with a complete clinical response.

The mucosal immune system: primary target for HIV infection and AIDS

Despite intensive research, several questions remain regarding the pathogenesis of infection with HIV-1. Recently, it has been shown that simian immunodeficiency virus (SIV) selectively targets and destroys specific subsets of CD4+ T cells that are abundant in mucosal tissues but rare in peripheral lymphoid tissues. This finding could be highly relevant in explaining a major paradox in the infection and elimination of CD4+ T cells during HIV infection: the progressive decline in the number of CD4+ T cells in the blood, despite the paucity of HIV-infected cells in this tissue. This article discusses the hypothesis that infection with HIV and SIV, and the resulting disease, is governed by the state of cellular activation and the expression of chemokine receptors by specific subsets of CD4+ T cells residing in mucosal lymphoid tissues, rather than those found in the peripheral blood or lymph nodes.

Immunocompromised host: from the early events until the impact of acquired immunodeficiency syndrome

The concept that microorganisms can modulate the host resistance was historically reviewed in the present article. The importance of African trypanosomiasis in the development of the research on immunosuppression as well as the impact of human immunodeficiency virus infection are discussed. Each day new opportunistic organisms establish a constant challenge for the correct diagnosis of concomitant infections in acquired immunodeficiency syndrome. The importance of parasite infection in the balance of host resistance in the third world was emphasized. Finally, some aspects of Leishmania as opportunistic organisms were presented.

Invasive amoebiasis: an emerging parasitic disease in patients infected with HIV in an area endemic for amoebic infection

OBJECTIVES

To describe the incidence and presentations of invasive amoebiasis (IA) in patients with HIV infection in an area endemic for amoebic infection and to assess the role of the indirect haemagglutination (IHA) assay in the diagnosis of IA in HIV-infected patients.

DESIGN

Retrospective study of 18 cases of IA and HIV infection.

SETTING

A university hospital, the largest centre for management of HIV-associated complications in Taiwan.

METHODS

Medical, microbiological and histopathological records of 296 HIV-infected patients and serological data of IHA assay of 126 HIV-infected patients were reviewed to identify cases of IA from 23 June 1994 to 31 March 1999. An IHA titre > or = 1 : 128 was considered positive. Clinical characteristics of HIV-infected patients with IA and without IA were compared.

RESULTS

Eighteen of the 296 patients (6.1%) with HIV infection were diagnosed with IA: 12 patients were diagnosed with definite IA and six with probable IA. The clinical manifestations included amoebic colitis (13 patients), amoebic liver abscess (nine), both colitis and abscess (four), and pleural effusion (two). IA was the initial presentation of HIV infection in nine patients. Co-infection with other enteric pathogens was diagnosed in six patients with IA. Compared with the 161 patients without IA who were newly diagnosed with HIV infection, the nine patients with IA had a higher median CD4+ lymphocyte count (202 x 10(6)/l versus 33 x 10(6)/l; P = 0.0017), were less likely to be diagnosed with AIDS (55.6% versus 85.4%; P = 0.039), and had fewer concurrent AIDS-defining illnesses (median number 0 versus 2; P = 0.003). Estimated mean survival duration was not significantly different between the two groups (597 days versus 611 days). Fourteen out of 126 patients (11.1%) had an IHA titre > or = 1 : 128. Of the 18 patients diagnosed with IA, 13 had a titre > or = 1 : 128. The sensitivity of IHA assay in the diagnosis of IA was 72.2% (13 out of 18) and the specificity was 99.1% (107 out of 108). The positive predictive value of IHA test for IA of this patient population was 92.9% (13 out of 14) whereas the negative predictive value was 95.5% (107 out of 112).

CONCLUSION

IA is an increasingly important parasitic disease among patients with HIV infection in Taiwan. IHA assay has a good specificity and high negative predictive value in diagnosis of IA.

Epidemiology and management of diarrheal disease in HIV-infected patients

Diarrhea is the most common gastrointestinal symptom in human immunodeficiency virus (HIV) infection. It affects up to 90% of patients, becoming more frequent and severe as the immune system deteriorates. It often is associated with significant morbidity and mortality particularly in the developing countries. Gastrointestinal infections, some of which are attributable to inadequate sanitation and poor hygiene are the predominant cause of diarrhea, although multiple medications, including traditional herbs, also may be causes. The basic principles of management include detection of treatable causes, relief of symptoms, prevention of malnutrition, and psychosocial support. In up to 60% of cases, no cause can be identified, partly because of inadequate investigative facilities. Symptomatic treatment is the mainstay of management particularly when no cause can be identified. Unfortunately this can be extremely difficult when the patient is severely immune-suppressed. There is poor response to motility control drugs, such as loperamide, and others, such as octreotide, are too expensive. Fluid replacement should be started early to prevent excessive dehydration. This should be combined with nutritional support to prevent malnutrition. Psychosocial support, including counselling, for both the patient and the caring relatives, is required to alleviate anxiety, particularly when the diarrhea becomes intractable.

Intestinal parasites in patients with diarrhea and human immunodeficiency virus infection in Zimbabwe

OBJECTIVES

To determine the prevalence of intestinal parasites and risk factors for infection associated with diarrhea in HIV-infected patients in Harare, Zimbabwe.

DESIGN

Prospective observational study.

METHODS

Single stool samples were collected from 88 HIV-infected individuals presenting with diarrhea of greater than 1 week duration. Stools were examined for intestinal parasites using modified acid fast stain, fluorescence- labeled monoclonal antibody for Cryptosporidium parvum, as well as a modified trichrome stain and a PCR-based protocol for Enterocytozoon bieneusi.

RESULTS

C. parvum was detected in 9% (seven out of 82) of samples evaluated, but no Cyclospora was detected. E. bieneusi was detected in 18% (10 out of 55) of stool by trichrome staining and in 51% (28 out of 55) of stool examined by PCR. Risk factors for E. bieneusi infection were: living in rural areas, consumption of nonpiped water, contact with cow dung and household contact with an individual with diarrhea.

CONCLUSION

E. bieneusi infection was common in HIV-infected patients with diarrhea in Zimbabwe and may be acquired through person-to-person and fecal-oral transmission.

Prevalence of enteric pathogens in HIV-related diarrhea in the midwest

HIV disease is often associated with the condition of diarrhea, which may be accompanied by enteric infection or gastrointestinal tumor. This study prospectively investigated 27 episodes of chronic diarrhea in 24 patients with HIV infection. Upper endoscopy and sigmoidoscopy with biopsies at three sites (distal duodenum, sigmoid colon, and rectum) and viral and mycobacterial blood cultures were performed. Stool specimens were sent for standard tests. A primary infectious diagnosis was found in 10 (37%) of 27 episodes: cytomegalovirus (CMV) colitis (n = 4), 3 microsporidiosis (n = 3), cryptosporidiosis (n = 2), and colonic histoplasmosis (n = 1). Patients with CD4 counts of less than 50 cells/mm3 and with lower albumin levels were more likely to have a primary infectious diagnosis. Adenovirus was found in 7 cases but was often associated with another organism; these were not considered to be primary diagnoses. Blood cultures for viruses were not useful, and all mycobacterial cultures were negative. A flexible sigmoidoscopy with histologic examination and culture of biopsy samples were the diagnostic tools that yielded most infectious diagnoses. Follow-up showed that two thirds of patients improved with nonspecific antidiarrheal medications regardless of diagnosis. The study supports a minimalistic approach to the problem of diarrhea in patients with HIV infection. Upper and lower endoscopy lead to a precise diagnosis in a minority of cases, and the outcome was similar in patients with or without a primary infectious diagnosis.

Declining CD4+ T-lymphocyte counts are associated with increased risk of enteric parasitosis and chronic diarrhea: results of a 3-year longitudinal study

From January 1991 through September 1994, we observed people who were infected with HIV to assess the impact of enteric parasite-associated diarrhea. Respondents answered comprehensive questionnaires covering clinical and epidemiologic information and provided stool specimens monthly, which were examined unstained as well as stained with trichrome, chromotrope 2R, and with Kinyoun carbol-fuchsin, and with indirect immunofluorescence for Cryptosporidium. In all, 602 participants, who were interviewed, provided stool specimens at 3254 monthly visits. Parasites were associated with 50 of 354 (14.1%) acute diarrheal episodes (lasting < or = 28 days) and with 97 of 279 (34.8%) chronic episodes (lasting > 28 days). A parasite was associated with 31 of 222 (14.0%) episodes that occurred when CD4+ counts were > or = 200 cells/microl and with 150 of 566 (26.5%) episodes that occurred when CD4+ counts were < 200 cells/microl. The most commonly identified parasite was C. parvum, which was associated with 18 of 354 (5.1%) acute episodes and 36 (12.9%) of the 279 chronic episodes of diarrhea. In this patient population, enteric protozoan parasites were commonly associated with illness, particularly as immunosuppression worsened, and were more likely to be associated with chronic rather than acute diarrhea.

Prevalence of intestinal pathogens in HIV patients with diarrhea: implications for treatment

Patients infected with the human immunodeficiency virus (HIV) commonly experience diarrhea at some time during their illness. A variety of enteric pathogens are identified in 50-80% of these patients, depending on the intensity of the diagnostic work-up that is done. In addition to the common enteric pathogens, several unusual enteric pathogens are recognized to cause diarrhea especially in HIV patients. These include protozoan parasites such as Cryptosporidia, Isospora belli, Cyclospora cayatenensis and Microsporidium species bacteria such as enteropathogenic Escherichia coli and Mycobacterium avium-intracellulare, fungi including Candida albicans and Histoplasma capsulatum, and viruses such as astroviruses and caliciviruses. Diagnosis of these infections sometimes involves special procedures not readily available every where, and empiric therapy based on knowledge of the likely pathogens has been advocated for developing countries. This article reviews the currently available data on geographic variation of enteric pathogens in HIV patients with diarrhea and outlines a rational strategy for empiric therapy of these patients.

HIV/SIV enteropathy

Evidence is increasing that HIV/SIV-induced changes in the highly differentiated gut-associated immune system play a central role in the pathogenesis of gastrointestinal manifestations in HIV/SIV infection. It has been shown in both humans infected with HIV and in nonhuman primates infected with SIV that a rapid, very early, and more pronounced loss of CD4+ T-cells occurs in the mucosa in comparison to the peripheral blood. The loss of this important regulatory T-cell subset might explain mucosal immunodeficiency with the consequence of opportunistic mucosal infections. In addition, there is evidence that small intestinal damage occurs independently of secondary infections (HIV/SIV enteropathy). In late-stage human disease, HIV enteropathy is characterized by villous atrophy with hyporegeneration and dysmaturation of intestinal epithelial cells. In SIV infection of macaques, villous atrophy is a very early event; however, it is accompanied by crypt cell hyperproliferation. Early- and late-stage enteropathy in immunodeficiency virus infection may represent two types of immunologically mediated mucosal transformation in which the number and state of activation of regulatory T cells determine whether hypo- or hyperproliferative villous atrophy occurs.

Chronic diarrhoea among HIV-infected adult patients in Nairobi, Kenya

OBJECTIVES

Chronic diarrhoea and wasting are well recognized features of AIDS in Africa. However, because of resource constraints few comprehensive aetiological studies have been conducted in sub-Saharan Africa which have included a broad range of microbiological investigations. We undertook a prospective cross-sectional study of adult patients admitted to a government hospital in Nairobi, Kenya, to determine possible bacterial, mycobacterial, parasitic and viral causes of diarrhoea; to consider which may be treatable; and to relate microbiological findings to clinical outcome.

METHODS

Stool specimens from 75 consecutive HIV-seropositive patients with chronic diarrhoea admitted to a Nairobi hospital were subjected to microbiological investigation and results were compared with clinical findings and outcome. Stool samples were cultured for bacteria and mycobacteria and underwent light and electron microscopy; lawns of Escherichia coli were probed for pathogenic types and aliquots were tested for the presence of Clostridium difficile cytotoxin. Blood cultures for mycobacteria and other bacterial pathogens were performed as clinically indicated.

RESULTS

Thirty-nine (52%) patients yielded putative pathogens, the most common being Cryptosporidium sp. (17%), Salmonella typhimurium (13%), and Mycobacterium tuberculosis (13%). Of 41 patients investigated for pathogenic Escherichia coli, enteroaggregative E. coli and diffusely adherent E. coli were each found in four patients. Thirty-one (41%) patients died. Detection of cryptosporidium cysts was the single most significant predictor of death (X2 = 5.2, P<0.05). Many patients did not improve (21; 28%) or self-discharged whilst still sick (5; 7%) but five (7%) were diagnosed ante mortem with tuberculosis and treated and a further 13 (17%) showed improvement by time of discharge.

CONCLUSIONS

HIV-infected patients with chronic diarrhoea in Nairobi have a poor outcome overall, and even with extensive investigation a putative pathogen was identified in only just over half the patients. The most important step is to exclude tuberculosis; and the most useful investigation appears to be Ziehl-Neelsen staining. Other potentially treatable gram-negative bacterial pathogens, S. typhimurium, Shigella sp. and adherent E. coli were, however, common but require culture facilities which are not widely accessible for definitive identification. Further studies focussing on simple ways to identify sub-groups of patients with treatable infections are warranted.

Strongyloides stercoralis infection in AIDS

Strongyloides stercoralis infection in humans continues to be a subject that has frequently inspired reviews and papers. Within the AIDS epidemic, interest gathered momentum with the inclusion of this infection in the indicator diseases list, and its subsequent removal 5 years later by the CDC. These actions have prompted a debate as to whether this infection has special significance in patients with AIDS and whether its exclusion from the CDC criteria is justified. A detailed review of the world literature reveals an increased awareness and diagnosis of this infection in patients with AIDS which takes the form of dissemination, a rapid course, and a usually fatal outcome.

Enteropathy in Zambians with HIV related diarrhoea: regression modelling of potential determinants of mucosal damage

BACKGROUND

AIDS is characterised by small intestinal mucosal damage, but its aetiopathogenesis is poorly understood. Enteric infections in Africa differ from those in northern countries, where protozoan infections have been associated with severe enteropathy in AIDS patients.

AIMS

To characterise enteropathy in Zambian AIDS patients compared with local controls, and to assess relative contributions of enteric infection, nutritional impairment, and immune dysfunction.

METHODS

Computer aided mucosal morphometry of small intestinal biopsy specimens from 56 HIV infected Zambians with persistent diarrhoea and 26 diarrhoea free controls, followed by regression modelling.

RESULTS

Patients with HIV related diarrhoea had reduced villous height and increased crypt depth compared with controls. There was no difference between HIV positive and negative controls. In regression models applied to AIDS mucosal measurements, villous height and crypt depth were related to nutritional parameters and to serum soluble tumour necrosis factor receptor p55 concentration. Crypt depth was also related to lamina propria plasma cell count. Intestinal infection was found in 79%, which consisted predominantly of microsporidia in 34%, Isospora belli in 24%, and Cryptosporidium parvum in 21%, but detection of these enteropathogens was not related to severity of enteropathy.

CONCLUSIONS

Nutritional and immune disturbances were associated with enteropathy, accounting for over one third of the variation in mucosal morphometric parameters.

Gastrointestinal pathology in HIV-infected patients

Specific pathologic processes, particularly oral, esophageal, and intestinal infections, are common in the alimentary tract of AIDS patients. Many of these diseases are adequately assessed only by biopsy with histologic examination. Most are rare or unreported in immunocompetent hosts and are easily missed by those not familiar with them. This article describes the gross or endoscopic and histologic appearances and the diagnostic criteria for enteric pathologic processes seen in HIV-infected individuals.

Cryptosporidiosis in Houston, Texas. A report of 95 cases

Cryptosporidiosis is an important cause of diarrhea. We identified 95 patients with cryptosporidiosis over a 6-year period in our county hospital system, including 9 children and 86 adults infected with the human immunodeficiency virus (HIV). Risk factors included male-to-male sexual practices and Hispanic race. Diarrhea, weight loss, and gastrointestinal complaints were the most common symptoms at presentation. Among the HIV-infected adults, 20 (23%) developed biliary tract disease. Biliary involvement was associated with low CD4 counts. Treatment with paromomycin and antimotility agents was effective in reducing diarrheal symptoms in 54 of 70 (77%) patients with the acquired immunodeficiency syndrome (AIDS), although there was a high rate of relapse. Paromomycin did not prevent the development of biliary disease. Biliary disease responded to cholecystectomy or sphincterotomy with stent placement. Though often a cause of morbidity, cryptosporidiosis was only rarely the cause of death, even among patients with HIV. Cryptosporidiosis continues to be an important medical problem even in developed-countries. Current methods of prevention and treatment are suboptimal.

Investigation of chronic diarrhoea in acquired immunodeficiency syndrome. A prospective study of 155 patients

BACKGROUND AND AIMS

The optimum diagnostic investigation for patients with acquired immunodeficiency syndrome (AIDS) and diarrhoea is not known. Often no pathogen is detected and it is unclear whether this is because pathogens are absent in some patients or the investigations used fail to detect them. The hypothesis that AIDS related diarrhoea is usually due to an infection, which can be identified by a simple diagnostic strategy based on the results of intensive investigation of a cohort of such patients, was investigated.

METHODS

155 patients with AIDS and chronic diarrhoea underwent contemporaneous examination of stools, duodenal, jejunal, and rectal biopsy specimens and duodenal aspirate for bacterial, protozoal, and viral pathogens. A decision tree analysis was used to determine the best sequential diagnostic strategy for clinicians.

RESULTS

128 of 155 patients investigated (83%) had at least one potential pathogen. The presenting clinical features could not predict the presence or site of the pathogens. Stool analysis identified the most pathogens (93 of 199, 47%). Rectal biopsy was essential for the diagnosis of cytomegalovirus and adenovirus. Duodenal biopsy was as helpful as jejunal biopsy and detected some treatable pathogens missed by other methods. Electron microscopy, impression smears, and duodenal aspirate yielded little extra information. If gut biopsy was reserved for patients without a stool pathogen, some treatable pathogens would have been missed.

CONCLUSION

Most patients with AIDS and chronic diarrhoea have at least one gut pathogen, which can be identified by stool analysis and light microscopic examination of duodenal and rectal biopsies. Some pathogens will be missed unless all these investigations are done on all such patients.

Causes of chronic diarrhea in patients with AIDS in Thailand: a prospective clinical and microbiological study

A prospective study was designed to investigate the causes of chronic diarrhea in AIDS patients in Thailand. Forty-five patients from Bamrasnaradura Infectious Diseases Hospital were enrolled. Extensive investigations included multiple stool examinations for ova and parasites, using the stool formalin-ether concentration method, stool culture, stool acid-fast bacilli (AFB) stain, stool modified AFB stain, esophagogastroduoscopy with duodenal aspirate and biopsy, and colonoscopy with biopsy. Biopsied specimens were examined with H&E, Giemsa, Gram, Periodic acid Schiff, and AFB stains. Definitive causes were found in 29 patients (64.4%). Of these 29, 7 patients were found to habor more than 1 pathogen (15.5%). The most commonly found enteric pathogen was Cryptosporidium parvum (20.0%). Less frequently found pathogens were Mycobacterium tuberculosis (17.8%), Salmonella spp. (15.5%), Cytomegalovirus (11.1%), Mycobacterium avium intracellulare (6.6%), Strongyloides stercoralis (4.4%), Giardia lamblia (4.4%), Cryptococcus neoformans (2.2%), Histoplasma capsulatum (2.2%), Campylobacter jejun (2.2%), and Cyclospora cayetanensis (2.2%). Salmonella spp., Mycobacterium tuberculosis, and Mycobacterium avium intracellulare infections were shown to be more common in Thailand than in African countries.

The prevalence and aetiology of persistent diarrhoea in adults in urban Zambia

As the AIDS pandemic has spread, diarrhoea in adults has become a major burden on health care institutions in central Africa and on the families of sufferers. In order to assess the magnitude of the problem, we carried out a survey of households in a high population density township of Lusaka to determine the prevalence of persistent diarrhoea in adults. We also carried out a study of the causes of persistent diarrhoea in patients attending the University Teaching Hospital, Lusaka. The community survey assessed 460 households, representing a sample of 1440 adults. 94 adults were reported as having had diarrhoea in the 2 weeks prior to the survey, implying an attack rate of 1.74 per adult per year. Of these 94 cases, six had diarrhoea of between 2 and 4 weeks duration, and ten had diarrhoea of over 4 weeks duration. In the hospital study, 75 (97%) out of 77 patients with diarrhoea of over 1 months' duration were HIV seropositive; potentially pathogenic parasites were found in 61/75 (81%) of seropositives. This information indicates that persistent diarrhoea in adults, mostly related to HIV infection, is likely to be an important and growing reservoir of enteric pathogens and represents a significant burden on hospitals and relatives. This emerging problem in sub-Saharan Africa may foreshadow developments in other continents.

Epidemiology of cryptosporidiosis among European AIDS patients

OBJECTIVE

To study epidemiology and possible risk factors associated with the development of cryptosporidiosis among European patients with AIDS.

METHODS

An inception cohort of 6548 patients with AIDS, consecutively diagnosed from 1979 to 1989, from 52 centres in 17 European countries was studied. Data on all AIDS defining events were collected retrospectively from patients' clinical records. Kaplan-Meier estimates, log rank tests and Cox proportional hazard models were used to examine for possible risk factors associated with cryptosporidiosis.

RESULTS

Cryptosporidiosis was diagnosed in 432 (6.6%) patients, 216 at time of the AIDS diagnosis and 216 during follow-up. The probability of being diagnosed with cryptosporidiosis at AIDS diagnosis was significantly lower for intravenous drug users (1.3%) than for homosexual men (4.1%) and for patients belonging to other transmission categories (4.0%) (p < 0.001). The probability was also higher for patients from Central Europe compared with patients from South Europe (4.1% versus 2.5%, p = 0.005). The rate of developing cryptosporidiosis after the diagnosis of AIDS was 3 per 100 patient years of follow-up. The rate was significantly lower for intravenous drug users than for homosexual men (relative risk 0.34, 95% confidence limits 0.22-0.54) and for women compared with men (RR 0.43 (0.21-0.87)). The risk was higher in North Europe than in South and Central Europe. In a multivariate analysis only transmission category remained a significant predictor for the development of cryptosporidiosis.

CONCLUSION

The development of cryptosporidiosis in AIDS patients may be associated with sexual risk behaviour.

Diarrheogenic bacterial enteritis in acquired immune deficiency syndrome: a light and electron microscopy study of 52 cases

Diarrhea, the etiology of which often is obscure, is a major complication of human immunodeficiency virus (HIV) disease. Diarrheogenic bacterial infections (eg, enteropathogenic Escherichia coli) are diagnosed traditionally by stool analysis rather than by examination of endoscopic biopsy specimens. Although E coli rarely have been associated with diarrhea in HIV/acquired immunodeficiency syndrome (AIDS) patients, neither have they routinely been sought. Endoscopic ileal and colorectal biopsy specimens from AIDS-positive patients with chronic diarrhea were analyzed by light and transmission electron microscopy (TEM). The surface epithelium of many large intestinal biopsy specimens previously diagnosed with, for example, nonspecific colitis, regularly showed disarray, degeneration, and necrosis, often with polymorphonuclear neutrophils (PMNs) and eosinophils, irregular cell aggregates, cell shedding, and defects. The crypts were not involved nor were consistent changes noted in the lamina propria. Closer scrutiny of 52 of these biopsy specimens showed gram-negative coliform bacteria intimately associated with histopathology in four distinct patterns. In 22 biopsy specimens, including two from infants, four morphological types of bacilli were observed that adhered to and effaced the brush border in the classic manner with cytoskeletal rearrangement and pedestals. Other bacterial morphologies and/or patterns of epithelial interaction also were observed (ie, thin bacilli intercalated between microvilli [n = 7], loosely associated bacilli [n = 21], and enterocyte invasion by long rods [n = 2]). Three patients also had minor ileal involvement. Infection was greatest in the right colon and coinfections (eg, microsporidia, Mycobacterium avium complex, adenovirus, and especially cytomegalovirus) were documented in 37% (19 of 52) of specimens. Diarrheogenic bacterial infections, some of the E coli type, may be an important cause of diarrhea in HIV disease. Their precise characterization is needed so that stool samples, not endoscopic biopsy specimens, can be used for diagnosis.

Diagnosis of intestinal microsporidiosis by examination of stool and duodenal aspirate with Weber's modified trichrome and Uvitex 2B strains

Severe, chronic diarrhea is a frequent complication of human immunodeficiency virus disease, and intestinal microsporidiosis is being recognized with increasing frequency in patients with AIDS. Noninvasive, cost-effective techniques are needed to optimize its diagnosis. Weber's modified trichrome stain (MTS) and the fluorochrome Uvitex 2B stain were used to detect microsporidial spores in smears of stool and duodenal aspirate (DA) samples received from human immunodeficiency virus-infected patients for examination for ova and parasites. Of 305 samples (292 stool and 13 DA samples) from 140 patients examined by MTS, 83 samples from 26 (18.6%) of the patients were positive for microsporidia (23 patients diagnosed initially and 3 diagnosed upon review). A subset of the samples studied by MTS consisting of 108 smears of stool and DA specimens from 60 patients was examined by Uvitex 2B. All 44 samples positive by MTS were also positive by Uvitex 2B. In addition, seven specimens and three patients were initially detected as positive by Uvitex 2B only (all three patients were positive also by MTS upon review). Confirmation of the diagnosis was obtained for 24 of 26 smear-positive patients by duodenal biopsy and/or stool transmission electron microscopy. Of 114 patients with stained smears negative for microsporidia, 23 had duodenal biopsies which showed no microsporidia. For the 43 patients who underwent duodenal biopsy, the sensitivity of both the MTS and the Uvitex 2B methods compared with biopsy results was 100%. Of six patients with negative duodenal biopsies and positive stained smears, four had microsporidia demonstrated by stool transmission electron microscopy. The examination of stool and DA smears stained by Uvitex 2B and/or MTS is a sensitive, noninvasive test for diagnosis of intestinal microsporidiosis which can be successfully implemented in a clinical laboratory. Strict adherence to precise diagnostic criteria is necessary to avoid incorrect results. The simultaneous use of both staining methods enhances performance and may provide greater accuracy, especially for patients with light infections.

Natural history and prognosis of diarrhoea of unknown cause in patients with acquired immunodeficiency syndrome (AIDS)

This paper is a prospective study of patients with advanced human immunodeficiency virus infection and chronic diarrhoea for which no cause could be found after extensive investigations, including examination of multiple stool specimens for all known faecal pathogens and the histological examination of small and large bowel biopsy specimens. Of 39 such patients recruited from 155 prospectively investigated patients, eight had a possible cause of diarrhoea identified on follow up investigations, including small bowel neoplasms in three and cytomegalovirus in two. In 17 of the remaining 31 the diarrhoea resolved completely in a mean of seven months from its onset. Eleven had continuing mild or intermittent diarrhoea and three had more than 1 litre of diarrhoea daily for which no cause could be found. The median survival for patients with 'pathogen negative' diarrhoea was 48.7 months, which is similar to that of control patients with no diarrhoea and significantly longer than that of matched patients with a gastrointestinal pathogen (9.6 months).

Submicroscopic profile of Isospora belli enteritis in a patient with acquired immune deficiency syndrome

Small bowel mucosal fragments from a human immunodeficiency virus-positive female patient with chronic diarrhea were investigated by transmission electron microscopy, and Isospora belli enteritis was documented. The submicroscopic profile was characterized by a moderate abnormality of mucosal architecture with reduction in height of villi and hypertrophy of crypts. Stages of both asexual (trophozoite, schizont and merozoite) and sexual (macrogametocyte) phases of the life cycle of the parasite were identified in the epithelium, always enclosed within a parasitophorous vacuole. Moreover, the presence of occasional extracellular merozoites in the intestinal lumen and in the lamina propria near or within lymphatic vessels was documented. These findings expand the current knowledge of this parasite regarding its capacity to survive in an extracellular environment and document a possible mechanism by which extraintestinal infection can take place.

Contribution of tuberculosis to slim disease in Africa

OBJECTIVES

To assess the contribution of tuberculosis to the aetiology of the HIV wasting syndrome (slim) in Africa, a condition usually considered an enteropathy.

METHODS

Clinical examination and representative necropsy study of adult patients positive for HIV.

SETTING

Hospital medical wards in Abidjan, Ivory Coast.

SUBJECTS

Adults positive for HIV.

MAIN OUTCOME MEASURES

CD4 T lymphocyte counts before death, clinical and anthropometric data, and gross and microscopic pathology.

RESULTS

Necropsy was done on 212 HIV positive adults. Tuberculosis was found in 41 of 93 with the clinical HIV wasting syndrome and in 32 of 119 without (odds ratio 2.1, 95% confidence interval 1.2 to 4.0). A significant association existed between the prevalence of tuberculosis at necropsy and the degree of cadaveric wasting (no wasting 25% (15/59); moderate wasting 40% (23/58); skeletal wasting 44% (42/95); P = 0.02). Wasting was also associated with a history of chronic diarrhoea, but no association existed between diarrhoea and tuberculosis. Median CD4 T lymphocyte counts were lowest in wasted patients irrespective of findings at necropsy and in those with chronic diarrhoea (< 60 x 10(6)/l).

CONCLUSION

Wasting and chronic diarrhoea are late stage manifestations of HIV disease in Africa. The importance of tuberculosis as a contributing factor in the pathogenesis of the slim syndrome has been underestimated. In nearly half of patients dying with severe wasting, tuberculosis was the dominant pathological finding.

Intestinal mucosal inflammation associated with human immunodeficiency virus infection

The role of the human immunodeficiency virus type-1 (HIV) in producing intestinal disease was studied prospectively in 74 HIV-infected individuals with (43) or without (31) the acquired immunodeficiency syndrome (AIDS). Thirty-one subjects had enteric infections; all but one had AIDS. Alteration in bowel habits was the most common symptom and occurred independently of enteric infections. Abnormal histopathology was present in 69% of cases, and the finding was associated with altered bowel habits. An HIV-associated protein, p24, was detected in 71% of biopsies by ELISA assay. Tissue p24 contents varied with disease stage and were highest in HIV-infected individuals without AIDS (Walter Reed classes 3 and 4). Tissue p24 detection was associated with both altered bowel habits and histologic mucosal abnormalities. Tissue contents of the cytokines, tumor necrosis factor-alpha and interleukin-1 beta, were higher in HIV-infected individuals than in controls and their elevations were independent of enteric infection. We conclude that HIV reactivation in the intestinal mucosa may be associated with an inflammatory bowel syndrome in the absence of other enteric pathogens.