Prevalence of Giardia infection in households of Giardia cases and risk factors for household transmission.

BACKGROUND: Giardia is a leading but neglected cause of infectious gastroenteritis worldwide and is treatable. There is a substantial burden of undetected Giardia in the UK and for every one case of Giardia reported to national surveillance there are 14 cases in the community. We aimed to ascertain the prevalence of, and risk factors associated with secondary household Giardia infections to assess the burden of infection and inform control measures. METHODS: We identified all giardiasis cases notified in nine local authorities in Lancashire between June 2014 and June 2015, and invited their household contacts to submit faecal specimens for Giardia testing and complete a risk factor questionnaire. We estimated the proportion of households with additional Giardia infection. We compared household risk factors between households with and without additional Giardia using Fisher's exact test. We used multivariable logistic regression to identify independent risk factors for additional Giardia infections. RESULTS: We identified additional Giardia infections in 30% (27/91) of included households. A total of 41 infections were found from 212 household members, of which 37 were asymptomatic. The majority of infections were assemblage B (57%) but there were also a high number of mixed infections (20%). Risk factors significantly associated with additional household infections were; having children under 5 years in the household (odds ratio 42; 95% confidence intervals 10-178) and the presence of gastrointestinal illness in the household before the onset of the index case (odds ratio 9; 95% confidence intervals 1.5-48). CONCLUSIONS: Our finding of a high household prevalence of asymptomatic infection has raised the public health question of whether treatment of asymptomatic household contacts may be justified in preventing Giardia re-infection of the index case or in preventing secondary cases and household clusters. We recommend the communication of this risk in household contacts of Giardia and reinforcement of standard hygiene controls.

Determination of Giardia duodenalis assemblages and multi-locus genotypes in patients with sporadic giardiasis from England.

BACKGROUND: The protozoan Giardia duodenalis is a common but highly diverse human parasite that comprises a complex of seven morphologically identical genetic assemblages, further divided into sub-assemblages. There is very little information available on the diversity of Giardia sub-assemblages and multi-locus genotypes infecting people in the United Kingdom. In this study we studied the molecular epidemiology of Giardia in symptomatic patients from North West England. METHODS: Whole faecal DNA was extracted from the faecal samples of 406 Giardia cases and the parasites assemblage, sub-assemblage and multi-locus genotype were determined using PCR amplification, DNA sequencing and phylogenetic analysis of the beta-giardin, glutamate dehydrogenase, triose-phosphate isomerase and small-subunit ribosomal RNA genes. Information about age, gender and self-reported clinical outcomes was also collected from the patients to check for differences associated with the infecting Giardia assemblage. RESULTS: Our results showed a difference in the age prevalence of the two assemblages, with assemblage A being more common in older cases. Cases infected with assemblage B more often reported vomiting and a longer illness than cases infected with assemblage A. The majority of infections (64%) were caused by assemblage B followed by assemblage A (33%), while mixed-assemblage infections were rare (3%). Assemblage A isolates mostly belonged to the sub-assemblage AII and showed completed identity with previously described isolates. The level of genetic sub-structuring was significantly higher in assemblage B isolates, since a higher proportion of novel assemblage B sequences was detected compared to assemblage A. A high number of assemblage B sequences showed heterogeneous nucleotide positions that prevented the unambiguous assignment to a specific sub-assemblage. Both previously described and novel multi-locus genotypes were described in both assemblages, and up to 17 different assemblage B multi-locus genotypes were found. CONCLUSIONS: We have produced the first data on the parasite multi-locus genotypes in the UK and have demonstrated that the molecular diversity of Giardia is similar to other developed countries. Furthermore, we showed that the parasite assemblages infecting humans may be associated with patients of different ages and with different clinical outcomes.

Investigation of Volatile Organic Compounds Emitted from Faeces for the Diagnosis of Giardiasis.

BACKGROUND: Giardiasis is a common intestinal infection caused by the flagellated intestinal protozoan Giardia duodenalis. Several methods are available for the laboratory diagnosis of Giardia, ranging from the microscopic identification of the parasite trophozoite and cyst stages, to immunodiagnosis and PCR. Giardia has unique metabolic pathways resulting from its lack of mitochondria, making it an ideal target for volatile organic compound (VOC) profiling. AIM: To characterise the VOC profile of stool infected with Giardia to detect differences from those found in samples of diarrhoea without Giardia or other infections. METHOD: Stool was obtained from patients with confirmed Giardia infection and controls with diarrhoea but no identifiable infection. Faecal headspace gas extraction and gas chromatography-mass spectrometry were used to extract and identify VOCs. RESULTS: More than 100 VOCs were identified when control and Giardia groups were combined, of which 24 showed significant differences between the two groups (p<0.05). Three VOCs had a significantly greater prevalence amongst Giardia cases (p<0.0001) and 9 VOCs showed a significant difference in terms of abundance (p<0.05). AUROC analysis demonstrated a value of 0.902. CONCLUSION: There is a significant difference in the VOC profile of stool from subjects infected with Giardia spp, when compared with non-infected controls. These findings can be explained by the unique metabolism of Giardia.

Case-Control Study of Risk Factors for Sporadic Giardiasis and Parasite Assemblages in North West England.

Giardia duodenalis is a major cause of infectious gastroenteritis worldwide, and it is diversified into eight genetic assemblages (A to H), which are distinguishable only by molecular typing. There is some evidence that the assemblages infecting humans (assemblages A and B) may have different transmission routes, but systematically acquired data, combining epidemiological and molecular findings, are required. We undertook a case-control study with Giardia genotyping in North West England, to determine general and parasite assemblage-specific risk factors. For people without a history of foreign travel, swimming in swimming pools and changing diapers were the most important risk factors for the disease. People infected with assemblage B reported a greater number of symptoms and higher frequencies of vomiting, abdominal pain, swollen stomach, and loss of appetite, compared with people infected with assemblage A. More importantly, keeping a dog was associated only with assemblage A infections, suggesting the presence of a potential zoonotic reservoir for this assemblage. This is the first case-control study to combine epidemiological data with Giardia genotyping, and it shows the importance of integrating these two levels of information for better understanding of the epidemiology of this pathogen.

Immune response to pneumococcal conjugate vaccination in asplenic individuals.

Asplenic individuals are at increased risk of infection with Streptococcus pneumoniae. The immune response to pneumococcal conjugate vaccine has not been investigated in this clinical risk group. We investigated immune responses to pneumococcal vaccination in asplenic individuals. Eligible subjects aged > or =4 years received one dose 7-valent pneumococcal conjugate vaccine (PCV7) and, if no prior 23-valent polysaccharide vaccine (PPV23) had been received within previous 5 years, one dose was given 6 months following PCV7. Pre- and post-vaccination blood samples were taken. Pneumococcal serotype-specific IgG levels were determined for 9 serotypes; the 7 in PCV7 plus serotypes1 and by standardized ELISA. One hundred and eleven asplenic individuals were recruited [median age 54.8 years, (18.1-81.8)]. Median age at splenectomy was 29.6 years (3.6-78.3); 108 (97.3%) individuals had previously received PPV23. Compliance with UK recommendations on immunization and prophylaxis in this group was poor, 91 (82%) subjects had received Haemophilus influenzae type b conjugate vaccine and only 68 (62%) had received meningococcal serogroup C conjugate vaccine. In total 61 (55%) subjects were taking antibiotic prophylaxis and 12 subjects had reported previous invasive pneumococcal disease, five episodes of which occurred post-splenectomy. High serotype-specific IgG concentrations were observed pre-PCV7, with significant increases (p < 0.01) in geometric mean concentrations pre- to post-PCV7 for the PCV7 serotypes. Post-PCV7, between 27% (serotype 14) and 69% (serotype 23F) of subjects had a > or =2-fold rise in IgG. Pre-PCV7, the percentage of individuals with levels > or =0.35 microg/mL ranged between 77% (serotype 4) and 97% (serotypes 14, 19F), whilst post-PCV7 this was 90% (serotype 6B) and 99% (serotype 14). No significant increases were observed post-PPV23. Asplenic individuals responded well to PCV7, though protective levels were demonstrated pre-PCV7 in majority of participants due to prior PPV23. Although immunogenic, there is insufficient evidence here to recommend routine PCV7 immunization over PPV23 immunization in adult asplenic individuals.

General practice factors and MMR vaccine uptake: structure, process and demography.

BACKGROUND: Despite the fall in MMR uptake between 1998 and 2004, some general practices managed to sustain remarkably high MMR coverage. METHODS: The aim of the study was to identify general practice factors associated with high MMR vaccine coverage. The study population included 257 general practices in Cumbria and Lancashire in 2005. Practice level MMR coverage data for 2002-04 were obtained from the child health information systems of eight Primary Care Trusts (PCTs) and linked to information on practice structure, census indicators for deprivation and ethnicity data at lower level super output area and information from a questionnaire survey of practice nurses. RESULTS: Mean MMR uptake was 86.4% with a range from 59 to 98%. Twenty-eight per cent (74/257) practices achieved the Department of Health higher target payment level of 90%. The uptake was not associated with practice size, the number of general practitioners (GPs) or practice nurses. There was no correlation between uptake and deprivation or the percentage of non-white population. There was a strong negative association between MMR uptake and barriers to housing and services (r = -0.230, P < 0.001). On the basis of a questionnaire response rate of 75.9%, having a strategic approach to MMR with clear objectives was associated with MMR uptake of 90% or above (odds ratio, 3.76, 1.26-12.04). There was no association between immunization by GP, practice nurse or health visitor. CONCLUSIONS: There are no easily identifiable characteristics of high-uptake MMR practices although having a strategic approach to MMR is important. Practices in rural areas should endeavour to ensure easy access to child vaccination. High uptake can be achieved by practices in deprived areas. Further research is needed to identify practice system factors associated with high MMR uptake.

Multiple norovirus genotypes characterised from an oyster-associated outbreak of gastroenteritis.

The diversity of norovirus (NV) genotypes was investigated in persons who were ill with acute gastroenteritis associated with the consumption of oysters. Initial results from a commercial enzyme immunoassay (EIA) indicated a mixed NV genogroup I (GI) and II (GII) outbreak. A reverse-transcriptase (RT)-PCR for NVs was applied to nucleic acid extracted from faecal specimens collected from symptomatic cases. Using primers that amplified contiguous sequences in the ORF1/2 region of the NV genome and a hemi-nested PCR derived from this assay, three different GII and two GI NV genotypes were detected and the strains were characterised by DNA sequencing. Using this approach a recombinant NV genotype, rGII-3a (recombinant Harrow/Mexico) the predominant strain identified in several symptomatic cases from the outbreak, was detected and characterised. No other gastroenteric viruses, including rotavirus, astrovirus, sapovirus and adenovirus 40/41 were detected by RT-PCR and PCR.

Lip and tongue piercing: experiences and views of general dental practitioners in South lancashire.

PURPOSE OF THE STUDY: To ascertain the numbers of patients with pierced lips or tongues seen by dentists during routine consultations. The study also examined the provision of advice by dentists, and the nature of piercing-related complications. BASIC PROCEDURE: A postal questionnaire was sent to dentists in two Primary Care Trust areas in South Lancashire. MAIN FINDINGS: Sixty-four of the 106 questionnaires were returned, giving a response rate of 60%. Sixty-two dentists (96.9%) reported that they had seen patients with lip or tongue piercings during the previous 12 months and that they had seen a mean number of 2.8 patients with lip piercing and a mean of 9.0 patients with tongue piercing. A total of 56.5% of the dentists gave advice on oral hygiene and 79.0% on possible damage to the oral structures. Twenty-seven dentists (43.5%) said that their patients had oral health problems as a result of lip or tongue piercing. PRINCIPAL CONCLUSIONS: The dentists who responded to the questionnaire commonly saw lip and tongue piercings. All dentists should therefore be prepared to offer appropriate advice. A public health information leaflet available in all medical and dental practices would help to ensure that patients were better informed about body piercing and its complications.