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PubMed2002

HIV1 and the gut in the era of highly active antiretroviral therapy.

The gut and its gut-associated lymphoid tissue serve as a preferential site for HIV1 entry, active viral replication, reservoir, and HIV-mediated CD4 cell apoptosis. The widespread use of highly active antiretroviral therapy (HAART) has resulted in a significant decrease in the incidence of opportunistic enteric pathogens as a consequence of immune recovery. Nonetheless, patients with advanced HIV1 disease who were recently diagnosed or have poor response to HAART can still suffer from opportunistic infections with pathogens such as Cryptosporidium, microsporidia, Isospora belli, Cyclospora cayetanensis, Mycobacterium avium complex, and cytomegalovirus, among others. This review describes the impact of HIV1 infection on gut immune function, the salient features of the most common opportunistic enteric pathogens and HIV-associated enteropathy, and the effects of immune reconstitution after introduction of HAART.

AIDS-Related Opportunistic Infections↗
PubMed1988

Prevalence of enteric pathogens in homosexual men with and without acquired immunodeficiency syndrome.

We studied 388 homosexual or bisexual men from the Baltimore-Washington area to define the spectrum of enteric pathogen carriage in a population at high risk for "gay bowel syndrome" in association with human immunodeficiency virus infection. Seventy-seven patients with acquired immunodeficiency syndrome, 68 gay men with symptoms of acute diarrhea or proctitis, and 243 gay men without gastrointestinal symptoms and participating in a natural history study of human immunodeficiency virus infection were selected for study. Approximately 12% of the asymptomatic men harbored at least one enteric pathogen; the most frequently recovered were Chlamydia trachomatis, herpes simplex virus, and Giardia lamblia. Men carrying a pathogen were more likely to be human immunodeficiency virus seropositive (48%) than men without a pathogen (25%) (p = 0.018), more likely to have fewer T helper cells (p = 0.015), and more likely to have a mucopurulent exudate (p = 0.014). We recovered an agent of enteric disease from 68% of gay men presenting with diarrhea or proctitis. Campylobacter species, herpes simplex virus, Neisseria gonorrhoeae, C. trachomatis, G. lamblia, and Shigella species were identified most frequently. The most common pathogen associated with diarrhea in acquired immunodeficiency syndrome was Cryptosporidium (16% of 49 cases). Other agents identified were Clostridium difficile, Vibrio parahemolyticus, Campylobacter species, G. lamblia, Isospora, and cytomegalovirus. Approximately half of the identifiable etiologic agents of diarrhea in acquired immunodeficiency syndrome patients were treatable with antibiotics, but these agents required special culture procedures for detection.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Opportunistic infections in AIDS in developed and developing countries.

The acquired immune deficiency syndrome (AIDS) is fundamentally the same disease in all parts of the world, but the prevalence of microorganisms in an environment governs the patterns of disease arising from reactivated latent infections, invading pathogens and opportunistic infections. AIDS in Africa has certain characteristic presentations. Enteropathic AIDS is most common: Cryptosporidium and Isospora belli are identified in up to 60% of patients, but it is uncertain whether they are the causes of diarrhoea. Pneumocystis carinii pneumonia is rare. Tuberculosis, both pulmonary and extrapulmonary, is the supreme complicating infection. Herpes zoster is frequently the first clinical presentation, and has a 95% positive predictive value for HIV positivity. Measles may be more frequent in infants born to HIV-infected mothers, and appears to be worse in HIV-infected children. There is accelerated progress of both diseases in patients infected by HIV and Mycobacterium leprae. Salmonellosis is frequent. There is no direct interaction between malaria and HIV, but, by being a potent cause of anaemia, malaria enhances transmission of HIV to children through blood transfusion. HIV-positive subjects are liable to new or reactivated visceral leishmaniasis with dissemination to unusual sites. Cerebral toxoplasmosis is common. There are no apparent interactions between HIV and helminths, although there is one report of hyperinfection with Strongyloides stercoralis. Cryptococcal meningitis has high frequency. Infections with Histoplasma encapsulatum are common in tropical America, but there has been no increase of frequency of H. duboisii in Africa since the advent of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Intestinal parasites in Zambian patients with AIDS.

Previous studies have found a high prevalence of Isospora belli and Cryptosporidium parvum infections in African acquired immune deficiency syndrome (AIDS) patients with chronic diarrhoea. We aimed to determine the prevalence of gastrointestinal parasite in AIDS patients in hospital, not only those with diarrhoea, and to compare them with the general community. Clinically diagnosed AIDS patients in a Zambian teaching hospital were interviewed and examined, and stool specimens were studied for parasite infection. A control group was recruited from adults in a township near Lusaka. Of 90 AIDS patients (58% male), 50 (56%) had chronic diarrhoea and 9 (10%) had diarrhoea of shorter duration. In the control group (105 adults; 85% female), only one complained of diarrhoea. A variety of intestinal protozoa and helminths was found in 57% of AIDS patients and 88% of the community members. Isosporiasis was detected in 7, and cryptosporidiosis in 2, AIDS patients, all with diarrhoea, but not in any control. Strongyloides was found in 2 AIDS patients with diarrhoea and one community resident. Hospital patients with AIDS had fewer Entamoeba coli and E. histolytica infections, probably because of previous chemotherapy. We conclude that AIDS predisposes to isosporiasis and cryptosporidiosis, but not to infection with extracellular intestinal parasites, such as Entamoeba species, Blastocystis, Chilomastix, Endolimax, Ascaris and Necator.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

A field and laboratory evaluation of a commercial ELISA for the detection of Giardia coproantigens in humans and dogs.

A capture enzyme linked immunosorbent assay (CELISA) was evaluated for its ability to detect Giardia coproantigens in the faeces of humans and dogs in the Perth metropolitan area and Aboriginal communities in Fitzroy Crossing, Western Australia. Using zinc sulphate flotation and light microscopy, Giardia cysts and/or trophozoites were observed in 8 of 57 (14%) human stool samples from Perth and 21 of 55 (38%) stool samples from Fitzroy Crossing, after 2 separate examinations. Analysis of diagnostic sensitivity using the ELISA revealed that coproantigens were detected in all 29 human samples (100%) in which Giardia cysts and/or trophozoites were also present. Coproantigens were detected in one further sample from Perth and in 3 samples from Fitzroy Crossing in which no Giardia cyst or trophozoite was observed. The specificity of the test, as defined using Fitzroy Crossing samples free from Giardia, was 91%. The assay did not cross-react with Giardia-free stool samples containing Hymenolepis nana, Entamoeba coli, E. hartmanni, Chilomastix mesnili or Ancylostoma duodenale. Giardia cysts and/or trophozoites were also observed in 11 of 32 dog faecal samples (34%) in Perth and 11 of 29 dog samples (38%) in Fitzroy Crossing, after one zinc sulphate examination. The sensitivity of the ELISA for dogs was 64% and 55% for Perth and Fitzroy Crossing specimens respectively. The specificity was 95% when Fitzroy Crossing samples were used. Other parasites observed in Giardia-free faecal samples from dogs which did not produce a positive reaction with the kit were Ancylostoma caninum, Sarcocystis sp. and Isospora sp.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Gastrointestinal disease in the immunocompromised patient.

Gastrointestinal (GI) disease is frequent in all types of immunocompromised patients but occurs with greatest frequency in patients with acquired immunodeficiency syndrome (AIDS). Thus, much of this review deals with human immunodeficiency virus (HIV)-related GI diseases. Gastrointestinal diseases in other immunocompromised patients are compared with those in patients with AIDS. Conditions unique to transplant recipients, such as graft-versus-host disease (GVHD) and posttransplant lymphoproliferative disorders (PTLDs), are discussed separately. We have divided these GI diseases into four main categories: (1) HIV-related inflammatory conditions other than opportunistic infections (HIV-related enteropathy, proctocolitis, and CD8 lymphocytosis); (2) inflammatory conditions unrelated to HIV or opportunistic infections (neutropenic enterocolitis, regional enteritislike enteropathy, and GVHD); (3) opportunistic infections (illnesses caused by herpesvirus, cytomegalovirus, and miscellaneous other viruses; Mycobacterium, Candida, Histoplasma, Cryptococcus, Cryptosporidium, Microsporida, Isospora, Leishmania, Toxoplasma and Strongyloides organisms as well as Pneumocystitis carinii; and (4) neoplasias (Kaposi's sarcoma [KS], AIDS-related non-Hodgkin's lymphoma [NHL], HIV-related Hodgkin's disease [HD], PTLDs, and miscellaneous neoplasms). The prevalence, pathogenesis, clinical manifestations, gross pathological findings, and microscopic features of each disease entity are discussed.

AIDS-Related Opportunistic Infections↗
PubMed1990

Ileal and jejunal absorptive function in patients with AIDS and enterococcidial infection.

Small intestinal absorptive function was investigated in six patients with the acquired immunodeficiency syndrome (AIDS) who had diarrhoea and weight loss. Proximal function was assessed by [14C]Triolein test of fat absorption. Distal function was determined by a test of bile acid absorption in which the loss of radio-labelled synthetic bile acid, 75seleno-23-homocholic acid-taurine ([75Se]HCAT), from the enterohepatic circulation was quantified by abdominal gamma-scanning and by a vitamin B12-intrinsic factor absorption test. Concurrently indirect tests of small intestinal bacterial overgrowth ([14C]glycocholate and breath hydrogen) were carried out. In addition, jejunal histological examination and stool microscopy and culture for enteropathogens were performed. Fat absorption was reduced in all six patients, four of whom had jejunal villous atrophy. Bile acid and vitamin B12 absorption were normal in four subjects. Enteropathogens were not detected in any of the four subjects with normal terminal ileal absorptive function. In contrast, reduced bile acid and vitamin B12 absorption were detected in two of six subjects. Both patients had an enteropathogen (Cryptosporidium spp. and Isospora belli) present on stool and jejunal histological examination. Neither subject had evidence of small-intestinal bacterial overgrowth. AIDS patients therefore may have normal ileal absorptive function in the presence of jejunal disease. Infection with Cryptosporidium spp. or I. belli may however, be associated with severe ileal dysfunction.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Endoparasites of birds of paradise in Papua New Guinea.

General endoparasitiasis in 16 species of captive birds of paradise (BOP) in Papua New Guinea ranged from 60.0 to 79.6% during 1977, 1978, 1981, 1983 and 1984. Percent prevalence of the three major groups of parasites during the five survey years was as follows: haematozoa, 36.7-53.0%; coccidia, 42.2-63.3% and helminths, 35.6-67.3%. Percent prevalence of blood parasites in the years 1977 and 1984 was: Haemoproteus 14.3, 20.0; Plasmodium 10.2, 4.5; Haemoproteus or Plasmodium 18.4, 8.9; Leucocytozoon 6.1, 6.7; Trypanosoma 8.2, 6.7; microfilaria 10.2, 4.5. Oocysts of Eimeria paradisaeai, Isospora raggianai and I. volki were common, as were oocysts morphologically distinct from these three species. The most frequently observed cestode eggs belonged to Raillietina and Biuterina species. Eggs of Strongyloides, Capillaria, Syngamus and Trichuris species of nematodes were also recovered. The Magnificent Bird of Paradise (Diphyllodes magnificus) had the highest mean eggs per gram (EPG) during the five survey years, except in 1978 when the highest mean was recorded from the Lesser Bird of Paradise (Paradisaea minor). Highest mean oocysts per gram (OPG) for the first 3 years were also recorded from D. magnificus, but Paradisaea raggiana had the highest mean OPG in 1983 and 1984. Possible causes for the greatest prevalence of endoparasites in the birds during 1977 and 1984, despite their having been regularly treated prophylactically, are considered.

Animals↗
PubMed1991

Helminth and protozoan parasites in dogs and cats in Belgium.

This study investigates the level of helminthic and protozoal infestation over the last 10 years in strays, well-cared-for dogs and cats. Determination of the prevalence of infections was based either on faecal examination or on worm counts at necropsy. Of 2324 faecal flotations (NaCl sp.gr. 1.20) of stray dogs, 34.2% had eggs or proglottids of one or more worm species consisting of Toxocara canis (17.4%), Toxascaris leonina (10.1%), Uncinaria stenocephala (11.4%), Trichuris vulpis (7.0%) and cestodes (2.1%). Isospora oocysts were observed in 5.2% of the dogs. The data on the distribution of the various worm species in the positive dogs indicate that T. canis eggs were by far the most common (50.9%). Necropsy data from 212 infected dogs indicate that 38.9% were infected with T. canis and 33.7% with T. leonina. The overall prevalence of worm infestation of 246 well-cared-for kennel dogs, based on worm egg counts by the McMaster technique, was 36.1%. Of 30 feline faecal samples examined by flotation, 83.3% were positive for parasites, including Toxocara cati (60%), Ancylostoma tubaeformae (36.6%), Taenia (Hydatigera) taeniaeformis (20%) and coccidia (30%). Toxocara cati was the most frequently found worm species at the necropsy of 25 cats (52%). Toxoplasma was not observed.

Animals↗
PubMed1992

Development and characterization of monoclonal antibodies to first-generation merozoites of Eimeria bovis.

Merozoites of Eimeria bovis were harvested from bovine monocyte cell cultures and used to immunize BALB/C mice. Spleens from immunized mice were removed and the cells fused with mouse myeloma cells. Supernates from resulting hybridoma cell lines were examined for antibodies to first-generation E. bovis merozoites using an indirect immunofluorescent antibody (IFA) assay. Three positive cell lines were identified and cloned by limiting dilution. All three cell lines produced immunoglobulins of the IgG1 isotype that recognized antigens in the anterior half to two-thirds of the merozoites. Specificity of the monoclonal antibodies was examined with the IFA assay against sporozoites of E. bovis, sporozoites and merozoites of Eimeria papillata from mice and Eimeria tenella from chickens, sporozoites of Isospora suis from pigs, and tachyzoites of Toxoplasma gondii and Neospora caninum from cell cultures. Monoclonal antibodies from the three clones reacted with the anterior end of E. bovis sporozoites, but did not react with the other parasites examined. None of the monoclonal antibodies reacted with merozoite antigens in immunoblots.

Animals↗
PubMed1990

Gastroenterological aspects of AIDS in the Third World.

Gastrointestinal disease is the commonest presentation of AIDS in the Third World. Diarrhoea and weight loss are particularly common. Although many pathogens may be found, chronic cryptosporidiosis is the most frequent and there remains no specific effective therapy. Isospora belli is found in less than 10% of cases, but may be treated with cotrimoxazole, and long-term maintenance treatment to prevent relapse is effective. Oral disease, especially with candidiasis, is increasingly recognized and may be controlled with topical antifungal agents. The outlook for patients in the Third World who present with gastrointestinal opportunistic infections associated with HIV infection is particularly dismal. Specific antiviral therapy, which has at least brought some hope and longer survival to patients in developed countries, remains largely unavailable in the Third World.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Effects of toltrazuril on the growth of piglets in herds without clinical isosporosis.

Isospora suis is a widely prevalent and economically important parasite. The antiprotozoal compound, toltrazuril, was given as a single treatment to piglets without clinical signs in 10 herds. The daily weight gain (DWG) and mortality between the treatment date and weaning was compared on each herd in 10 treated and 10 control litters. The faeces of control litters were examined for oocyst excretion. In six herds, no oocysts were detected and treatment had no effect on DWG or mortality. In four pig herds, oocysts were detected and toltrazuril treatment significantly improved DWG by 25 g (P=0.003). Mortality rate was not affected. The partial economic benefit of toltrazuril treatment in positive herds was 0.20 euros per piglet. A single toltrazuril treatment of piglets in herds without clinical signs of isosporosis but with oocysts detected significantly improved DWG and was considered economically justified on each farm.

Animals↗
PubMed2004

Prevalence of intestinal parasites in dogs under veterinary care in Maracaibo, Venezuela.

The prevalence of intestinal parasites in dogs presented to the Veterinary Policlinic of the University of Zulia (PVU) was measured between January and December 2001. A total of 614 fecal samples were evaluated by the fecal flotation method. One or more species of parasites was identified in 218 (35.5%) dogs. The parasites most frequently detected were: Ancylostoma spp. (24.5%), Toxocara canis (11.4%) and Isospora spp. (8.1%). Single parasitic infections were present in 149 (24.3%) dogs. The age distribution of intestinal parasites in dogs less than 1 year old had a higher overall prevalence than those dogs over 12 months of age. There was no significant difference in the prevalence between male (38.9%) and female (31.7%) dogs. There was a significantly (P < 0.05) greater prevalence of parasites in mixed-breed dogs (40.3%) as compared with pure-breed dogs (30.8%). A significant difference (P < 0.05) was detected between the general prevalence of January and December compared to August.

Age Factors↗
PubMed2004

Cyclospora cayetanensis, a food- and waterborne coccidian parasite.

Food- and waterborne coccidia including Cryptosporidium parvum, Cyclospora cayetanensis, Sarcocystis hominis and Sarcocystis suihominis, and Isospora belli are cyst-forming apicomplexan protozoa that cause intracellular infections, predominantly in the epithelial cells of the intestine. They are transmitted by oocysts from person-to-person by the fecal-oral route or via contaminated water or food. The most common symptom of infection is diarrhea, however, asymptomatic infections occur. Infections are associated with intestinal inflammation, with pathological lesions such as villus blunting, and abnormal function such as malabsorption. Mild-to-moderate, self-limiting diarrhea is common in healthy individuals ingesting infective stages of these organisms. However, patients with immune dysfunction can have severe intestinal injury and prolonged diarrhea. Diagnosis in many cases is made by a microscopic examination of the stool, and the use of appropriate staining techniques, but more recently molecular methods for detection are used increasingly. Effective antimicrobial treatment for prolonged infection in immunocompromised patients is available for most of these infections. These gastrointestinal coccidial pathogens have important similarities in epidemiology, disease pathogenesis, clinical manifestations, diagnosis, and treatment. Although there are many other cyst-forming coccidia of public health, veterinary and/or economic importance, discussion in this chapter will be limited to C. cayetanensis, as an important example of the group. Aspects of the biology, epidemiology, diagnosis, disease, treatment and control are considered. This parasite is considered to be an emerging pathogen. From 1990 to 2000, there were 11 foodborne outbreaks of cyclosporosis in North America that affected at least 3600 people. There are many outstanding questions regarding this parasite and under-reporting is common because general diagnostic methods for intestinal parasites are inadequate for detection of Cyclospora.

Animals↗
PubMed2004

Survey of intestinal parasites in pigs from intensive farms in Guangdong Province, People's Republic of China.

The prevalence of intestinal parasites was investigated in intensive pig farms in Guangdong Province, China between July 2000 and July 2002. Faecal samples from 3636 pigs (both sexes and five age groups) from 38 representative intensive pig farms employing different parasite control strategies were examined for the presence of helminth ova and protozoan oocysts, cysts and/or trophozoites using standard techniques. Of the 3636 pigs sampled, 209 (5.7%) were infected with Trichuris suis, 189 (5.2%) with Ascaris, 91 (2.5%) with Oesophagostomum spp., 905 (24.9%) with coccidia (Eimeria spp. and/or Isospora suis) and 1716 (47.2%) with Balantidium coli. These infected pigs were mainly from farms without a strategic anti-parasite treatment regime. Concurrent infection of multiple parasites was common, and T. suis was the most common nematode infecting breeding, young and mature pigs. The results of the present investigation provide relevant 'base-line' data for assessing the effectiveness of control strategies against intestinal parasitism in intensively raised pigs in Guangdong Province, China.

Animals↗
PubMed2006

Incidence of Neospora caninum and other intestinal protozoan parasites in populations of Swiss dogs.

The protozoan parasite Neospora caninum is one of the most important abortifacient organisms in cattle worldwide. The dog is known to act as definitive host although its potential role as infection source for bovines still remains unelucidated. The aim of the present study was to compile initial epidemiological data on the prevalence and incidence of N. caninum in Swiss dogs acting as definitive hosts. Thus, 249 Swiss dogs were investigated coproscopically in monthly intervals over a period of 1 year. A total of 3289 fecal samples was tested by the flotation technique. Among these, 202 were shown to contain Sarcocystis sp. (6.1%), 149 Cystoisospora sp. (=Isospora sp.; 4.5%) and 25 Hammondia/Neospora-like oocysts (HNlO) (0.7%). All but one sample containing HNlO were from different dogs; one dog shed HNlO at two subsequent time points. Calculation of the yearly incidence for HNlO resulted in the surprisingly high value of 9.2%. Farm dogs exhibited a higher incidence for HNlO than urban family dogs. Thirteen out of the 25 HNlO-samples showed sporulation after 5 days incubation at room temperature. HNlO were further differentiated by species-specific PCR. However, all HNlO-samples were negative for N. caninum, Hammondia heydorni and Toxoplasma gondii. One reason may be the low oocyst density found in most fecal samples, which did not permit us to carry out PCR under optimal conditions. Three out of the 25 HNlO-cases contained enough oocysts to allow further enrichment and purification by the flotation technique. Subsequently, twenty to fifty sporulated HNlO-oocysts were orally administered to Meriones unguiculatus. All gerbils were seronegative for N. caninum at 5 weeks p.i. A N. caninum-seroprevalence of 7.8% was determined by ELISA upon 1132 serum samples collected from dogs randomly selected by veterinarians among their clinical patients.

Animals↗
PubMed1986

New developments in infectious diarrhea.

The past decade has produced exciting advances in our knowledge of infectious diarrhea. The list of potential enteric pathogens continues to grow with both the identification of new organisms, e.g., E. coli serotype O157:H7, and the recognition that previously characterized microorganisms, e.g., M. avium-intracellulare, can also cause gastrointestinal disease in immunosuppressed patients. Multiple investigations have led to a greater understanding of the epidemiology and clinical features of these illnesses. Application of modern biological techniques has yielded a number of diagnostic assays that are just now becoming clinically relevant. New drugs and treatment modalities for enteric infections have been developed and are now being evaluated in clinical trials. Despite these advancements, however, many questions still remain unanswered. For example, the etiology of the debilitating diarrhea in AIDS patients in whom no known intestinal pathogen can be identified remains unknown. The mechanism of diarrhea due to Cryptosporidium, Isospora, and Giardia remains elusive. And last, will new intestinal vaccines be effective in preventing diarrheal disease? Certainly, the next decade of research in enteric diseases should prove to be even more interesting than the last.

Adolescent↗
PubMed1999

Phylogenetic analysis of Sarcocystis spp. of mammals and reptiles supports the coevolution of Sarcocystis spp. with their final hosts.

Sequences of the small subunit rRNA genes were obtained for two coccidians, Sarcocystis dispersa and an unnamed Sarcocystis sp. which parasitise the European barn owl and an African viperid snake as their final host, respectively, and share mouse as their intermediate host. Phylogenetic analysis of the sequence data showed that Sarcocystis sp. from the viperid snake is most closely related to another Sarcocystis sp. isolated from an American crotalid snake, while S. dispersa grouped with other bird-transmitted species. The available dataset failed to resolve the evolutionary relationships among four major branches into which all Sarcocystidae and Isospora spp. were split. However, within these branches, the phylogenetic relationships of the majority of analysed members of the genus Sarcocystis reflected coevolution with their final, rather than intermediate hosts.

Animals↗