The prevalence of invasive amebiasis is not increased in patients with AIDS

Tissue Parasites in HIV Infection

PURPOSE OF REVIEW

The purpose of this review is to discuss the current knowledge of HIV and tissue parasite co-infection in the context of transmission enhancement, clinical characteristics, treatment, relapse, and clinical outcomes.

RECENT FINDINGS

The pathophysiology and clinical sequelae of tissue parasites in people living with HIV (PLWH) have been well described for only a handful of organisms, primarily protozoa such as malaria and leishmaniasis. Available published data indicate that the interactions between HIV and tissue parasites are highly variable depending on the infecting organism and the degree of host immunosuppression. Some tissue parasites, such as Schistosoma species, are known to facilitate the transmission of HIV. Conversely, uncontrolled HIV infection can lead to the earlier and more severe presentation of a variety of tissue parasites and can make treatment more challenging. Although much investigation remains to be done to better understand the interactions between consequences of HIV and tissue parasite co-infection, it is important to disseminate the current knowledge on this topic to health care providers in order to prevent, treat, and control infections in PLWH.

Neurocysticercosis and HIV Infection: what can we learn from the published literature?

OBJECTIVE

Infections caused by the human immunodeficiency virus (HIV) and by the larvae of Taenia solium (i.e., cysticercosis) are still widespread in many developing countries. Both pathologies modify host immune status and it is possible that HIV infection may modulate the frequency and pathogeny of cysticercosis of the central nervous system (i.e., neurocysticercosis [NCC]). To describe published cases of NCC among HIV-positive patients and to evaluate whether the characteristics of NCC, including frequency, symptoms, radiological appearance, and response to treatment differed between HIV-positive and HIV-negative patients.

METHODS

Forty cases of NCC/HIV co-infected patients were identified in the literature. Clinical and radiological characteristics, as well as response to treatment, were compared with non-matching historical series of NCC patients without HIV infection.

RESULTS

Most of these patients had seizures and multiple vesicular parasites located in parenchyma. Clinical and radiological characteristics were similar between HIV-positive and HIV-negative patients with NCC, as well as between immunocompromised and non-immunocompromised HIV-positive patients.

CONCLUSION

Our review did not reveal clear interactions between HIV and NCC. This may be partially due to the small number of cases and reliance on published research. A systematic, multi-institutional effort aiming to report all the cases of this dual pathology is needed to confirm this finding and to clarify the possible relationship between both pathogens.

Underestimated Amoebic Appendicitis among HIV-1-Infected Individuals in Japan

Entamoeba histolytica is not a common causative agent of acute appendicitis. However, amoebic appendicitis can sometimes be severe and life threatening, mainly due to a lack of awareness. Also, its frequency, clinical features, and pathogenesis remain unclear. The study subjects were HIV-1-infected individuals who presented with acute appendicitis and later underwent appendectomy at our hospital between 1996 and 2014. Formalin-fixed paraffin-embedded preserved appendix specimens were reexamined by periodic acid-Schiff (PAS) staining and PCR to identify undiagnosed amoebic appendicitis. Appendectomies were performed in 57 patients with acute appendicitis. The seroprevalence of E. histolytica was 33% (14/43) from the available stored sera. Based on the medical records, only 3 cases were clinically diagnosed as amoebic appendicitis, including 2 diagnosed at the time of appendectomy and 1 case diagnosed by rereview of the appendix after the development of postoperative complications. Retrospective analyses using PAS staining and PCR identified 3 and 3 more cases, respectively. Thus, E. histolytica infection was confirmed in 9 cases (15.8%) in the present study. Apart from a significantly higher leukocyte count in E. histolytica-positive patients than in negative patients (median, 13,760 versus 10,385 cells/μl, respectively, P = 0.02), there were no other differences in the clinical features of the PCR-positive and -negative groups. In conclusion, E. histolytica infection was confirmed in 9 (15.8%) of the appendicitis cases. However, only 3, including one diagnosed after intestinal perforation, were diagnosed before the present analyses. These results strongly suggest there is frequently a failure to detect trophozoites in routine examination, resulting in an underestimation of the incidence of amoebic appendicitis.

Association between Taenia solium infection and HIV/AIDS in northern Tanzania: a matched cross sectional-study

BACKGROUND

The frequency of Taenia solium, a zoonotic helminth, is increasing in many countries of sub-Saharan Africa, where the prevalence of the human immunodeficiency virus (HIV) is also high. However, little is known about how these two infections interact. The aim of this study was to compare the proportion of HIV positive (+) and negative (-) individuals who are infected with Taenia solium (TSOL) and who present with clinical and neurological manifestations of cysticercosis (CC).

METHODS

In northern Tanzania, 170 HIV+ individuals and 170 HIV- controls matched for gender, age and village of origin were recruited. HIV staging and serological tests for TSOL antibodies (Ab) and antigen (Ag) were performed. Neurocysticercosis (NCC) was determined by computed tomography (CT) using standard diagnostic criteria. Neurological manifestations were confirmed by a standard neurological examination. In addition, demographic, clinical and neuroimaging data were collected. Further, CD4⁺ cell counts as well as information on highly active antiretroviral treatment (HAART) were noted.

RESULTS

No significant differences between HIV+ and HIV- individuals regarding the sero-prevalence of taeniosis-Ab (0.6% vs 1.2%), CC-Ab (2.4% vs 2.4%) and CC-Ag (0.6% vs 0.0%) were detected. A total of six NCC cases (3 HIV+ and 3 HIV-) were detected in the group of matched participants. Two individuals (1 HIV+ and 1 HIV-) presented with headaches as the main symptom for NCC, and four with asymptomatic NCC. Among the HIV+ group, TSOL was not associated with CD4⁺ cell counts, HAART duration or HIV stage.

CONCLUSIONS

This study found lower prevalence of taeniosis, CC and NCC than had been reported in the region to date. This low level of infection may have resulted in an inability to find cross-sectional associations between HIV status and TSOL infection or NCC. Larger sample sizes will be required in future studies conducted in that area to conclude if HIV influences the way NCC manifests itself.

Ultrasound for patients in a high HIV/tuberculosis prevalence setting: a needs assessment and review of focused applications for Sub-Saharan Africa

Ultrasound is increasingly used in point-of-care applications and has great potential to support the diagnosis of infectious diseases, especially in resource-limited settings. A cross-sectional study was performed involving 100 Malawian patients with a clinical indication for ultrasound. Furthermore, the literature on point-of-care ultrasound (POCUS) in Sub-Saharan Africa was reviewed to establish its applicability, most frequent indications, findings, and implications for treatment, and therefore relevance in POCUS curricula, with a main focus on infectious diseases. In Malawi, the main indications for ultrasound were weight loss, abdominal pain, and shortness of breath. Abnormal findings were observed in 77% of patients, the most common being enlarged abdominal lymph nodes (n=17), pericardial effusion (n=15), splenic microabscesses (n=15), and pleural effusion (n=14). POCUS led to a change in treatment in 72% of patients. The literature on the various POCUS applications used in Malawi was reviewed, including focused assessment with sonography for HIV-associated TB (FASH), heart, liver, kidney, deep venous thrombosis (DVT), and gynaecology. Based on disease prevalence, impact of POCUS on treatment, and technical difficulty, it is proposed that FASH, heart, and DVT are the most relevant POCUS applications in comparable Sub-Saharan African settings and should be incorporated in POCUS curricula.

Multiple Amoebic Liver Abscess As Initial Manifestation in Hiv Sero-Positive Male

Amoebic liver abscess is the most frequent extra-intestinal manifestation of Entamoeba histolytica infection. Immunosuppression is known to predispose to amoebic liver abscess. Although amoebic liver abscess is seen more commonly in patients of Human-Immunodeficiency virus (HIV), first presentation of HIV sero-positive patient as multiple liver abscess is quite uncommon.The author reports an unusual case of multiple liver abscesses in an HIV seropositive patient. This middle aged male with history of multiple unprotected sexual encounters presented with spasmodic abdominal pain, fever, diarrhoea and weight loss along with generalised ill-health and painful liver enlargement. HIV-1 serology was found to be reactive. Imaging revealed an enlarged liver with multiple, irregular, hypoechoic foci characteristic of abscesses. Amoebic aetiology was later confirmed by percutaneous aspiration and microscopy. Administration of appropriate chemotherapeutics along with institution of antiretroviral therapy led to both clinical resolution as well as disappearance of lesions.

Management of protozoa-related diarrhea in HIV infection

Protozoa infections are an important cause of chronic diarrhea in patients infected with HIV. The introduction of highly active antiretroviral treatment to the management of HIV in the mid 1990s has led to a dramatic reduction in the incidence of these opportunistic infections in Europe and America. In contrast, in the developing world where such treatments are not readily affordable, protozoa-related diarrhea remains a major cause of morbidity and mortality in HIV-infected individuals. In this review, the optimum investigations required to diagnose these pathogens in HIV-related diarrhea, as well as current treatment options, will be discussed.

Treatment of symptomatic amebic colitis in human immunodeficiency virus-infected persons

While most Entamoeba histolytica appearing in male homosexuals infected with human immunodeficiency virus (HIV) is considered non-invasive in Western countries, and treatment of amebiasis in these persons has received very little attention, in Japan some male homosexual amebiasis patients infected with HIV complain of symptoms attributable to E. histolytica infection. We investigated whether symptomatic E histolytica amebic colitis in HIV-infected persons requires higher doses or longer duration of antiamebic drug therapy than in non HIV-infected patients. Four symptomatic amebic colitis patients infected with HIV-1, three of them severely immunocompromised, with CD4 cell counts <200/mm(3), were treated with oral metronidazole: 1500 mg a day for 10 days in 2 patients, 1000 mg a day for 10 days in 1 patient, and 1000 mg a day for 6 days and then 750 mg for 4 days in 1 patient, and good therapeutic results with no side effects were obtained. This indicates that symptomatic amebic colitis in HIV-infected persons can be successfully treated with metronidazole at the same dose and duration of treatment used in non-HIV-infected persons.

A serological study of cysticercosis in patients with HIV

Neurocysticercosis (NCC) has attained the importance of one of the most common cause of focal brain lesions in patients infected with HIV (human immunodeficiency virus). Adequate data regarding the rate of this co-infection is lacking. Therefore, the present study was carried out to determine the prevalence of cysticercosis among HIV patients residing in Puducherry or its neighboring districts of Tamil Nadu State, India. A total of one hundred blood samples were collected from HIV seropositive cases visiting JIPMER hospital, Puducherry, between June 2007 and May 2008. Enzyme immunotransfer blot (EITB) and enzyme linked immunosorbent assay (ELISA) were used to demonstrate anti- T. solium larval stage antibodies and Co-agglutination (Co-A) test was used to detect T. solium larval stage antigens in sera. Two HIV seropositive cases were found positive for anti-T. solium larval stage antibody by EITB and four were positive by ELISA. Only one sample was positive by both EITB and ELISA. No serum sample was found positive for T. solium larval stage antigen by Co-A test. The overall seropositivity detected by all the methods was 5% in this study group. The accurate clinical diagnosis of NCC in HIV is difficult due to deranged immunological parameters in the HIV infected patients. The results of this study provides important data on the prevalence of cysticercosis in HIV positive patients in Puducherry and neighboring areas which was previously unknown. This study will also increase awareness among physicians and public health agencies about T. solium cysticercosis in the selected group.

Advances in sexually transmitted infections of the gastrointestinal tract

The gastrointestinal mucosa is a target of many sexually transmitted infections, and major advances have increased our understanding of the consequences of such infections within the gastrointestinal system. HIV-1 is associated with a marked loss of mucosal CD4(+) T cells that express CC-chemokine receptor 5. This process seems to be more rapid and more severe in mucosa-associated lymphoid tissue than in the peripheral blood. Mechanistic insights into the underlying cause of acute and chronic gastrointestinal damage with HIV infection-microbial translocation, defects in intestinal epithelial barrier function and activation of a systemic immune response-have also been achieved. Increased understanding of the pathogenesis of mucosal HIV-1 infection may identify therapeutic targets to restore immunological function and the integrity of the intestinal mucosal epithelial barrier. The increasing prevalence of lymphogranuloma venereum in Europe, mostly in HIV-positive men who have sex with men, suggests a change in the epidemiology of what was previously considered to be a 'tropical' disease. The increasing incidence of acute HCV infection transmitted via sexual contact has also been fueled by high-risk sexual behaviors among men who have sex with men, many of whom are also HIV-positive. The first part of this Review discusses the pathogenesis and gastrointestinal complications of HIV infection, and the second part summarizes advances in our understanding of other sexually transmitted infections of the gastrointestinal system.

Management of Potential Neurocysticercosis in Patients with HIV Infection

In patients with human immunodeficiency virus, the diagnosis of neurocysticercosis can be complex, and the current diagnostic criteria may not apply. We report 3 cases and suggest including the CD4+ T lymphocyte count as an important factor in the proper diagnosis and treatment of patients with human immunodeficiency virus and potential neurocysticercosis.

The pathogenicity of Entamoeba histolytica is related to the capacity of evading innate immunity

The host and parasite factors that influence susceptibility to Entamoeba histolytica infection and disease are not well understood. Entamoeba histolytica pathogenicity has been considered by focusing principally on parasite rather than host factors. Thus, research has concentrated on explaining the molecular differences between pathogenic E. histolytica and non-pathogenic E. dispar. However, the amoeba molecules considered most important for host tissue destruction (amoebapore, galactose/N-acetyl galactosamine inhibitable lectin, and cysteine proteinases) are present in both pathogenic E. histolytica and non-pathogenic E. dispar. In addition, the genetic differences in pathogenicity among E. histolytica isolates are unlikely to completely explain the different outcomes of infection. Considering that the principal difference between pathogenic and non-pathogenic amoebas lies in their surface coats, we propose that pathogenicity of the amoebas is related to the composition and properties of the surface coat components (or pathogen-associated molecular patterns, PAMPs), and the ability of innate immune response to recognize these components and eliminate the parasite. According to this hypothesis, a key feature that may distinguish pathogenic (E. histolytica) from non-pathogenic (E. dispar) strains is whether or not they can overcome innate immune defences. A corollary of this hypothesis is that in susceptible individuals the PAMPs are either not recognized or they are recognized by a set of Toll-like receptors (TLRs) that leads to an inflammatory response. In both cases, the result is tissue damage. On the contrary, in resistant individuals the innate/inflammatory response, induced through the activation of a different set of TLRs, eliminates the parasite.

Enteric parasites and AIDS

OBJECTIVE

To report on the importance of intestinal parasites in patients with AIDS, showing relevant data in the medical literature, with special emphasis on epidemiology, diagnosis and treatment of enteroparasitosis, especially cryptosporidiosis, isosporiasis, microsporidiasis and strongyloidiasis.

DESIGN

Narrative review.

[An evaluation of the relationship between intestinal parasitoses and the risk factors for HIV in AIDS patients]

We conducted a cohort survey on 200 AIDS patients in São Paulo, SP, Brazil, to verify if the presence of enteroparasites is associated with the various risk factors for HIV infection. Diarrhea was significantly more frequent in the group of patients presenting enteroparasitosis (p < 0.00001). Giardia lamblia, found in 32 (16%) cases, was the most prevalent parasite. The presence of parasites in the stool samples was not significantly associated with risk factors for HIV infection, mainly when considering Giardia lamblia and Cryptosporidium parvum (p = 0.99 and 0.69, respectively). The controversy found in the literature indicates that additional studies should be done in the different geographical regions of the country.

Diagnosis and treatment of colonic disease in AIDS

The colon is a frequent site of gastrointestinal complications in patients with HIV infection, and these colonic disorders increase in frequency as immunodeficiency worsens. The most common clinical manifestations of colonic disease in AIDS are diarrhea, lower gastrointestinal bleeding, and abdominal pain. Toxic megacolon, intussuseption, typhlitis, idiopathic colonic ulcer, and pneumatosis intestinalis also have been described. In the HIV-infected patient with preserved immunity, the most common cause of colitis is bacterial, but as the degree of immunodeficiency worsens, opportunistic pathogens (CMV, protozoa, mycobacteria, fungi) and neoplasms become more frequent. The frequent use of antibiotics, chemotherapeutic agents, and frequent hospitalization increase the susceptibility to cf2Clostridium difficule cf1colitis. Endoscopy plays an integral role in the management of many colonic disorders in AIDS.

Invasive amoebiasis in two patients with AIDS and cytomegalovirus colitis

Homosexual persons or human immunodeficiency virus (HIV)-infected patients frequently excrete cysts of nonpathogenic strains of Entamoeba histolytica ("Entamoeba dispar"). However, invasive amoebiasis is rare. We report two patients with AIDS and cytomegalovirus colitis in whom invasive amoebiasis was histologically diagnosed. It is concluded that E. histolytica has to be considered in HIV-infected patients with colitis.

Review article: the therapy of gastrointestinal infections associated with the acquired immunodeficiency syndrome

Although there have been dramatic strides in the therapy of human immunodeficiency virus infection over the last few years, the number of infected people world-wide is tremendous and, at least in developing countries, continues to expand. Complications which involve the gastrointestinal tract are common in these patients, because the gut is a major site for involvement by opportunistic infections and neoplasms in patients with the acquired immunodeficiency syndrome. It is important to recognize the clinical spectrum of gastrointestinal diseases, as well as the appropriate and most cost-effective diagnostic strategies, as therapies for a number of these disorders are both widely available and high effective. This review summarizes the major gastrointestinal infections which are seen in patients with the acquired immunodeficiency syndrome, and their treatment.