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Traveller’s Diarrhoea and Intestinal Protozoal Diarrhoeal Disease

Blastocystis is a polymorphic intestinal parasite that is common in humans. A total of 51 asymptomatic and symptomatic patients positive for Blastocystis only were included in the study. Symptoms were mainly nonspecific gastrointestinal symptoms. Blastocystis isolates were xenically cultured and subtyped Blastocystis species subtype 3 was the predominant subtype. Intrasubtype differences (vacuolar/amoeboid presence) in subtype 3 morphotypes were observed in 32 asymptomatic and symptomatic subtype 3 cases and could possibly be related to Blastocystis pathogenic potential. Diverse morphologic features (vacuolar transiting to amoeboid), probably reflecting the progression from an asymptomatic to a symptomatic state, were observed in an asymptomatic subtype 3 carrier who later had symptoms. Searching for amoeboid forms might be helpful to presumptively screen symptomatic patients with subtype 3 or to follow up an asymptomatic subtype 3 carrier in case symptoms become evident before antiprotozoal treatment was attempted. Further studies on the roles of morphologic features and variation within Blastocystis species subtypes as predictors of symptoms are encouraged.

Brucella spp. are small, slow-growing, Gram-negative coccobacilli that are responsible for brucellosis, the most common zoonotic disease worldwide. Brucellosis is a notifiable disease in most countries. Brucellosis is also considered as an occupational, laboratory and travel-acquired disease. Brucella spp. are transmitted through consumption of raw animal products (food-borne brucellosis) and animal contact. They may be spread through droplets in the air; they are traditionally classified as a class B bioterrorism agent. Brucellosis incidents have been reported in relation to domestic animals. Brucella strains have been isolated from terrestrial and marine mammals. Brucella melitensis, B. suis and B. abortus differ in host range, pathogenicity and virulence. B. canis infections have rarely been reported. Current global trends on the incidence of brucellosis are reviewed. Brucellosis is often overlooked and can mimic other conditions; it may be acute, subacute or chronic in presentation, and may involve various body sites. Recent studies on endocarditis, osteoarticular, haematological, neurological and other involvements are reviewed. Relapses in brucellosis should also be considered. Collaboration between the microbiologist and the clinician is important for diagnosis, since diagnosis of brucellosis is based on laboratory testing by serology and, ultimately by culture, in the context of clinical presentation and history of recent or past exposure. Advanced PCR-based techniques may also be used to diagnose brucellosis. Today a combination of antibiotics are recommended in treatment, whereas further therapeutic approaches are possible. New challenges posed by international travel, animal trade, animal movement, and occupational migration to/from endemic countries may increase incidence of human cases and the risk of re-emergence of brucellosis in previously brucellosis free regions such as Northern and Central Europe. Animals are considered to be lifelong carriers of Brucella spp. providing a large continuous source of human infection. A lower incidence of human brucellosis is likely to result from a decrease in incidence of animal brucellosis. Control and surveillance strategies may depend on the level of healthcare development and the prevalence of reservoir hosts in the affected region. (C) 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins

Blastocystis is an anaerobic parasitic microorganism, which has been found in the intestinal tract of many vertebrates including humans. Recently, members of Blastocystis sp. were classified into nine subtypes, based on phylogenetic trees derived from sequence analysis of the small subunit ribosomal RNA (SSU rRNA) gene. The role of Blastocystis in human disease remains uncertain and the existence of pathogenic and non-pathogenic subtypes is under investigation. We report the development of a polymerase chain reaction (PCR)-based assay that is able to detect Blastocystis directly from human faeces. Furthermore, combined with single strand conformational polymorphism (SSCP) analysis and/or sequencing of the respective PCR product, the protocol can classify Blastocystis among the nine established subtypes. The method was applied to 45-positive and 30-negative faecal samples and proved to be highly sensitive and specific. Genotyping using SSCP analysis and sequencing revealed that subtype 3 is the most frequent in Greece, while subtypes 1, 2, 4, 6 and 7 are also present but in lower frequencies. Hopefully, the simplicity of the proposed method will contribute toward large-scale epidemiological studies for prompt clarification of the role of the parasite. (C) 2007 Elsevier Ltd. All rights reserved.