Summary: Blastocystis is an unusual enteric protozoan parasite of humans and many animals. It has a worldwide distribution and is often the most commonly isolated organism in parasitological surveys. The parasite has been described since the early 1900s, but only in the last decade or so have there been significant advances in our understanding of Blastocystis biology. However, the pleomorphic nature of the parasite and the lack of standardization in techniques have led to confusion and, in some cases, misinterpretation of data. This has hindered laboratory diagnosis and efforts to understand its mode of reproduction, life cycle, prevalence, and pathogenesis. Accumulating epidemiological, in vivo, and in vitro data strongly suggest that Blastocystis is a pathogen. Many genotypes exist in nature, and recent observations indicate that humans are, in reality, hosts to numerous zoonotic genotypes. Such genetic diversity has led to a suggestion that previously conflicting observations on the pathogenesis of Blastocystis are due to pathogenic and nonpathogenic genotypes. Recent epidemiological, animal infection, and in vitro host-Blastocystis interaction studies suggest that this may indeed be the case. This review focuses on such recent advances and also provides updates on laboratory and clinical aspects of Blastocystis spp.

New insights on classification, identification, and clinical relevance of Blastocystis spp.

Few data sources are available to assess the global and regional risk of sequelae from bacterial meningitis. We aimed to estimate the risks of major and minor sequelae caused by bacterial meningitis, estimate the distribution of the different types of sequelae, and compare risk by region and income. We systematically reviewed published papers from 1980 to 2008. Standard global burden of disease categories (cognitive deficit, bilateral hearing loss, motor deficit, seizures, visual impairment, hydrocephalus) were labelled as major sequelae. Less severe, minor sequelae (behavioural problems, learning difficulties, unilateral hearing loss, hypotonia, diplopia), and multiple impairments were also included. 132 papers were selected for inclusion. The median (IQR) risk of at least one major or minor sequela after hospital discharge was 19.9% (12.3-35.3%). The risk of at least one major sequela was 12.8% (7.2-21.1%) and of at least one minor sequela was 8.6% (4.4-15.3%). The median (IQR) risk of at least one major sequela was 24.7% (16.2-35.3%) in pneumococcal meningitis; 9.5% (7.1-15.3%) in Haemophilus influenzae type b (Hib), and 7.2% (4.3-11.2%) in meningococcal meningitis. The most common major sequela was hearing loss (33.9%), and 19.7% had multiple impairments. In the random-effects meta-analysis, all-cause risk of a major sequela was twice as high in the African (pooled risk estimate 25.1% [95% CI 18.9-32.0%]) and southeast Asian regions (21.6% [95% CI 13.1-31.5%]) as in the European region (9.4% [95% CI 7.0-12.3%]; overall I(2)=89.5%, p<0.0001). Risks of long-term disabling sequelae were highest in low-income countries, where the burden of bacterial meningitis is greatest. Most reported sequelae could have been averted by vaccination with Hib, pneumococcal, and meningococcal vaccines.

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Global and regional risk of disabling sequelae from bacterial meningitis: a systematic review and meta-analysis

Despite economic and medical advances, acute rheumatic fever and consequent rheumatic heart disease remain a major public health burden in low and middle-income countries, and a designated priority for the World Health Organisation. The clinical consequences are major and enduring, particularly for women of child-bearing age, and access to diagnosis, preventive therapy and transcatheter or surgical interventions remains a challenge. Herein, we provide a summary of key aspects of the condition, with particular focus on epidemiology, pathogenesis and immune mechanisms, diagnosis and clinical manifestations, contemporary management and preventive strategies.

/pdf/acute-rheumatic-fever-and-rheumatic-heart-disease-51xnxwizit.pdf

Acute rheumatic fever and rheumatic heart disease

Blastocystis hominis is a unicellular organism found commonly in the intestinal tract of humans and many other animals. Very little is known of the basic biology of the organism, and controversy surrounds its taxonomy and pathogenicity. There morphological forms (vacuolar, granular, and ameboid) have been recognized, but recent studies have revealed several additional forms (cyst, avacuolar, and multivacuolar). The biochemistry of the organism has not been studied to any extent, and organelles and structures of unknown function and composition are present in the cells. Several life cycles have been proposed but not experimentally validated. The form used for transmission has not been defined. Infections with the organism are worldwide and appear in both immunocompetent and immunodeficient individuals. Symptoms generally attributed to B. hominis infection are nonspecific, and the need for treatment is debated. If treatment appears warranted, metronidazole is suggested as the drug of choice, although failures of this drug in eradicating the organism have been reported. Infection is diagnosed by light microscopic examination of stained smears or wet mounts of fecal material. Most laboratories identify B. hominis by observing the vacuolar form, although morphological studies indicate that other forms, such as the cyst form and multivacuolar form, also should be sought for diagnosis.

Blastocystis hominis revisited.

Although case histories of depression preceding Parkinson's disease (PD) point to a possible pathophysiological relationship between these two disorders, there is as yet no epidemiological evidence to support this view. We compared the incidence of depression in patients later diagnosed with PD with that of a matched control population. Using data from an ongoing general practice-based register study, the lifetime incidence of depressive disorder was calculated for patients until their diagnosis of PD and compared with that of a matched control population from the same register. At the time of analysis, the register held information on 105,416 people. At the time of their diagnosis of PD, 9.2% of the patients had a history of depression, compared with 4.0% of the control population (χ2 = 22.388, df = 1, P < 0.001). The odds ratio for a history of depression for these patients was 2.4 (95% CI: 2.1–2.7). We concluded that the higher incidence of depression in patients who were later diagnosed with PD supports the hypothesis of there being a biological risk factor for depression in these patients. © 2003 Movement Disorder Society

Higher incidence of depression preceding the onset of Parkinson's disease: A register study

We treated 15 children with Sydenham's chorea with sodium valproate at a dose of 15 to 20 mg/kg/d. In 13 of them the chorieform movements disappeared within 1 week of therapy. The remaining 2 had incomplete response. Two patients relapsed; 1 of them responded to the reintroduction of valproate. The mean duration of treatment was 6.7 weeks. We observed no major side effects. This study strongly suggests that valproate is an effective drug in the treatment of Sydenham's chorea.

Effectiveness of sodium valproate in the treatment of Sydenham's chorea

During a 9-month hospital-based survey, the intestinal parasite Blastocystis hominis was detected in high numbers (five or more organisms per oil immersion field) in faecal specimens from 39 (2%) of 1960 children under 13 years old. Abdominal pain or discomfort with or without diarrhoea was present in 32 children categorized as acute (14), subacute (7) or chronic (11) cases with respective mean ages of 6.4, 7.3 and 8.7 years. They included three with other enteropathogens (Giardia lamblia, Cryptosporidium sp. or Hymenolepis nana). The remaining seven children had no gastrointestinal symptoms. The 14 acute cases (symptoms duration 1-11 days) were characterized by cramp-like abdominal pain, watery diarrhoea and vomiting. The seven subacute (3-4 weeks) and 11 chronic (3-12 months) cases presented with abdominal discomfort and/or loose non-watery stools. Four complained of flatus and eosinophilia was noted in six. All symptoms resolved with eradication of B. hominis or reduction to low numbers after metronidazole chemotherapy (28 cases) or with no treatment (four cases). This study would appear to support the role of the parasite as an enteropathogen in some children. A case control study is clearly needed to clarify the status of B. hominis as a pathogen.

Clinical report of Blastocystis hominis infection in children.

Forty-five neonates with bacterial meningitis admitted to a regional hospital in Kuwait over a 5-year period are reported. The attack rate was 6.7/10,000 live births. Listeria monocytogenes was the most common bacteria isolated (31 per cent), followed by Streptococcus agalactiae (15 per cent), and Escherichia coli (11 per cent). Gram negative pathogens constituted 38 per cent of the total. Ten patients died (22 per cent) and 10 (28 per cent of the survivors) developed severe neurological sequelae.

Bacterial meningitis in the newborn: a Kuwaiti experience.

Forty-eight Arab patients with steroid-responsive childhood nephrotic syndrome were studied for the frequency of HLA-A,-B,-C and-DR antigens. HLA-DR7 was significantly increased in the patient group (63% vs. 28%,P=0.0002) confirming reports of a DR7 association in other ethnic groups and indicating a universal association with this antigen. HLA-CW6 was also significantly increased (44% vs. 21%,P corr.=0.042). HLA-DQW1 was significantly reduced in the patients (29% vs. 57%,P corr.=0.012) as was HLA-CW4 (6% vs. 24%,P corr.=0.042).

HLA antigens in Arab children with steroid-responsive nephrotic syndrome.

SummaryLaron dwarfism is a rare inherited form of short stature. Most cases reported have been in people of Mediterranean origin, particularly Oriental Jews. We describe the first sibship in an Ara...

Laron dwarfism in the Arabian Gulf : a report of a sibship

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