Giardia duodenalis : New Research Developments in Pathophysiology, Pathogenesis, and Virulence Factors
Abstract
Giardia duodenalis is a very common, ubiquitous, intestinal protozoan parasite infecting animals and humans. Of the eight distinct genetic assemblages known to date, assemblages A and B are infectious to humans. Giardia is the most commonly recognized cause of traveller’s diarrhea. Giardiasis impairs weight gain and is responsible for a variety of extra-intestinal and post-infectious complications, including post-infectious irritable bowel syndrome, chronic fatigue, failure to thrive, and cognitive impairment. Giardiasis occurs in the absence of invasion of the intes...
Source: Current Tropical Medicine Reports - July 11, 2015 Category: Tropical Medicine Source Type: research
Sphingolipids, Lipid Rafts, and Giardial Encystation: The Show Must Go On
Abstract
Sphingolipids are sphingosine-based phospholipids, which are present in the plasma and endomembranes of many eukaryotic cells. These lipids are involved in various cellular functions, including cell growth, differentiation, and apoptosis. In addition, sphingolipid and cholesterol-enriched membrane microdomains (also called “lipid rafts”) contain a set of proteins and lipids, which take part in the signaling process in response to intra- or extracellular stimuli. Recent findings suggest that sphingolipids, especially glucosylceramide, play a critical role in inducing encystation and maintainin...
Source: Current Tropical Medicine Reports - July 11, 2015 Category: Tropical Medicine Source Type: research
Encystation of Giardia intestinalis— a Journey from the Duodenum to the Colon
Abstract
The intestinal protozoan parasite Giardia intestinalis has a simple life cycle consisting of disease-causing trophozoites and infectious cysts. The parasite differentiates into the cyst stage (encystation) when duodenal trophozoites are swept further down in the small intestine. The encystation process can be divided into an early and a late phase. Expressions of cyst wall sugars and proteins are induced early during encystation, and Giardia has developed special transport systems for cyst wall material. This is combined with disassembly of the flagella and adhesive disc. In the later phase of en...
Source: Current Tropical Medicine Reports - July 7, 2015 Category: Tropical Medicine Source Type: research
Drug Resistance in the Microaerophilic Parasite Giardia lamblia
Abstract
The microaerophilic parasite Giardia lamblia is a causative agent of dysentery affecting hundreds of millions of people around the globe every year. The symptoms of the disease, commonly referred to as giardiasis, are diarrhea, nausea, and malabsorption. Treatment of giardiasis is exclusively based on chemotherapy with antigiardial drugs, including metronidazole, albendazole, and nitazoxanide. In this review, all drugs currently used in the treatment of Giardia infections are discussed with a special emphasis on treatment failure and drug resistance. (Source: Current Tropical Medicine Reports)
Source: Current Tropical Medicine Reports - July 7, 2015 Category: Tropical Medicine Source Type: research
The Immunological Enigma of Human Giardiasis
Abstract
Giardiasis is a major cause of enteritis in humans worldwide. The disease is caused by two very distinct genetic groups (referred to as assemblages A and B) of the species complex Giardia duodenalis. The trophozoites stage colonizes the duodenum and jejunum of the small intestine and may cause a broad variety of disease outcomes that reach from asymptomatic carriers to patients with acute or chronic severe gastrointestinal complaints. Studies in immunocompromised patients imply that antibody-mediated acquired immune responses and a minimal T cell availability are of major importance for parasite ...
Source: Current Tropical Medicine Reports - July 4, 2015 Category: Tropical Medicine Source Type: research
Cryptococcal Meningitis: Diagnosis and Management Update
Abstract
Recent advances in the diagnosis and management of cryptococcal meningitis are promising and have been improving long-term survival. Point of care testing has made diagnosing cryptococcal meningitis rapid, practical, and affordable. Targeted screening and treatment programs for cryptococcal antigenemia are a cost-effective method for reducing early mortality on antiretroviral therapy (ART). Optimal initial management with amphotericin and flucytosine improves survival against alternative therapies, although amphotericin is difficult to administer and flucytosine is not available in middle- or low...
Source: Current Tropical Medicine Reports - April 22, 2015 Category: Tropical Medicine Source Type: research
The Lung Immune Niche in Tuberculosis: Insights from Studies on Human Alveolar Macrophages
Abstract
Tuberculosis (TB) is a disease that continues to cause global mortality and morbidity. Transmission of Mycobacterium tuberculosis (Mtb) occurs by aerosol transmission from an infected case, making the lung the primary portal of entry for the bacterium. Alveolar macrophages are the frontline cells involved in the control of subsequent replication and spread of disease. Although animal models have provided important information in the field of macrophage immunology and cell biology, human TB disease has several unique features. Therefore, an understanding of human alveolar macrophage biology and th...
Source: Current Tropical Medicine Reports - April 22, 2015 Category: Tropical Medicine Source Type: research
Advances in Tuberculosis Diagnostics
Abstract
Accurate and timely diagnosis is the first step for initiating effective treatment for tuberculosis (TB) and interrupting transmission. Worldwide, nearly one third of all TB cases go undetected or unreported each year. The emergence of extensively drug-resistant TB, in addition to challenges in detecting TB among children and people living with HIV has created an urgent need for better technologies. In the past 5 years, Xpert MTB/RIF has proved to be pathfinder for improved diagnosis. However, gaps remain. Currently, there is no molecular replacement for sputum smear microscopy at the level of ...
Source: Current Tropical Medicine Reports - April 20, 2015 Category: Tropical Medicine Source Type: research
Preventing Cryptococcosis—Shifting the Paradigm in the Era of Highly Active Antiretroviral Therapy
Abstract
Cryptococcosis remains a significant cause of morbidity and mortality among HIV-infected patients, especially in sub-Saharan Africa where it causes up to 20 % of AIDS-related deaths in HIV programs. A new, highly sensitive, and affordable point of care diagnostic test for cryptococcal infection, the lateral flow assay, can detect early sub-clinical cryptococcosis especially in areas with limited laboratory infrastructure. With a prevalence of detectable sub-clinical cryptococcal infection averaging 7.2 % (95 % CI 6.8–7.6 %) among 36 cohorts with CD4 <100 cells/μL in Africa, together wit...
Source: Current Tropical Medicine Reports - April 20, 2015 Category: Tropical Medicine Source Type: research
Histoplasmosis Infections Worldwide: Thinking Outside of the Ohio River Valley
Abstract
In the USA, histoplasmosis is generally thought to occur mainly in the Ohio and Mississippi river valleys, and the classic map of histoplasmosis distribution reflecting this is second nature to many US physicians. With the advent of the HIV pandemic, reports of patients with progressive disseminated histoplasmosis and AIDS came from regions of known endemicity, as well as from regions not thought to be endemic for histoplasmosis throughout the world. In addition, our expanding armamentarium of immunosuppressive medications and biologics has increased the diagnosis of histoplasmosis worldwide. Whi...
Source: Current Tropical Medicine Reports - April 10, 2015 Category: Tropical Medicine Source Type: research
Recent Advances in Burkholderia mallei and B. pseudomallei Research
This article summarizes the latest research progress in the fields of B. mallei and B. pseudomallei pathogenesis, vaccines, and diagnostics. (Source: Current Tropical Medicine Reports)
Source: Current Tropical Medicine Reports - March 24, 2015 Category: Tropical Medicine Source Type: research
