Chlamydia trachomatis conjunctivitis in the pre-pubertal child.

Much is reported in the literature about the transmission and presentation of Chlamydia trachomatis conjunctival infection in the neonate; however, there is a paucity of information available on infection in the older pre-pubertal child (>3 years of age). We present the case of a 7-year-old girl, referred for assessment at the sexual assault referral centre following the diagnosis of unilateral C. trachomatis conjunctivitis. This child underwent a rigorous multiagency child protection process, with input from medical professionals, social services and the police to investigate the possibility of child sexual abuse (CSA). However, a group consensus was reached that non-sexual close contact transfer of C. trachomatis from the mother was the most likely mode of transmission and cause of infection. We aim to take the reader through the complex path to this conclusion, the approach to sexually transmitted infections and potential CSA and what is currently known about chlamydial conjunctivitis in children beyond the neonatal period.

Risk behaviours of homeless people who inject drugs during an outbreak of hepatitis C, Northern Ireland, 2016-2017.

From July to August 2016, 4 homeless people who injected drugs (PWID) with acute or recent hepatitis C virus (HCV) infection were reported in Belfast. A multidisciplinary team including public health, homeless and addiction services undertook an investigation to identify risk behaviours and interrupt transmission chains. Recent HCV cases were defined as negative test within the previous year, or reported injecting for less than 1 year; acute cases had tested negative within the previous 6 months. Contacts in the injecting networks of cases were identified for testing. We undertook a cross-sectional survey using structured questionnaires to elicit risk behaviours for PWID and compare behaviours between self-reported hepatitis C positive and negative subjects. During the outbreak investigation until December 2017, 156 PWID were tested and 45 (29%) cases identified, including 7 (16%) recent and 13 (29%) acute infections. 68 PWID, including 12 cases, were interviewed. All respondents reported using heroin, with 76% injecting once or more daily. Sharing was reported for spoons (58%) and filters (53%), but also needles (27%) and syringes (29%). Hepatitis C positive individuals had higher odds to be injecting in public toilets (AOR 17, 95% CI 0.71-400, P < .05) when compared with hepatitis C negative individuals. Hepatitis C positive individuals were more likely to inject in public spaces, but all respondents indicated concerning risk behaviours. We recommend active surveillance with ongoing testing, expanding existing harm reduction programmes and access to bespoke services.

Metabolomics of cerebrospinal fluid from humans treated for rabies.

Rabies is a rapidly progressive lyssavirus encephalitis that is statistically 100% fatal. There are no clinically effective antiviral drugs for rabies. An immunologically naïve teenager survived rabies in 2004 through improvised supportive care; since then, 5 additional survivors have been associated with use of the so-called Milwaukee Protocol (MP). The MP applies critical care focused on the altered metabolic and physiologic states associated with rabies. The aim of this study was to examine the metabolic profile of cerebrospinal fluid (CSF) from rabies patients during clinical progression of rabies encephalitis in survivors and nonsurvivors and to compare these samples with control CSF samples. Unsupervised clustering algorithms distinguished three stages of rabies disease and identified several metabolites that differentiated rabies survivors from those who subsequently died, in particular, metabolites related to energy metabolism and cell volume control. Moreover, for those patients who survived, the trajectory of their metabolic profile tracked toward the control profile and away from the rabies profile. NMR metabolomics of human rabies CSF provide new insights into the mechanisms of rabies pathogenesis, which may guide future therapy of this disease.

Possible involvement of human bocavirus 1 in the death of a middle-aged immunosuppressed patient.

An immunosuppressed 61-year-old man went to the hospital with fever, nonproductive cough, and increasing shortness of breath. The subject died 8 days later of respiratory complications. PCR of respiratory samples as well as a blood sample revealed exceptionally high DNA levels of the emerging pathogen, human bocavirus 1 (HBoV1), a recently found pathogen associated with respiratory symptoms in young children. We describe the clinical progression of the case and discuss the potential role of HBoV1 in the outcome.

Reactivation of occult hepatitis B virus infection following cytotoxic lymphoma therapy in an anti-HBc negative patient.

Screening hepatitis B virus (HBV) surface antigen (HBsAg) and HBV core antibody (anti-HBc) is recommended prior to cytotoxic or immunosuppressive therapy. This case describes an anti-HBc negative, DNA positive occult HBV infection in a 71-year-old Caucasian male following rituximab-based treatment for follicular lymphoma. Pre-screening serology indicated negative HBsAg and anti-HBc. However, following sequential treatment cycles the patient developed weak HBsAg with a low HBV DNA load (<1,000 IU/ml), but remained anti-HBc negative. The DNA load peaked 5 months later (>1 × 10(6) IU/ml) and he was subsequently treated with Tenofovir. Currently the patient remains anti-HBc negative, and is anti-HBe negative, anti-HBs negative, HBeAg positive. No clinical or biochemical evidence of hepatitis has occurred. Sequencing and phylogenetic analysis identified the HBV genosubtype as D4, most probably acquired some years ago during a stay in Papua New Guinea, in spite of prior hepatitis B vaccination. Four amino acid substitutions were detected within the HBsAg loop yet none in the core protein. This case questions the dependability of anti-HBc testing and highlights the role of HBV DNA testing prior to and throughout cytotoxic or immunosuppressive regimes. As this case exemplifies, vaccination protects against clinical infection but may not exclude seronegative occult infection with the possibility of reactivation.

An endogenously activated antiviral state restricts SARS-CoV-2 infection in differentiated primary airway epithelial cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the coronavirus disease-19 (COVID-19) pandemic, was identified in late 2019 and caused >5 million deaths by February 2022. To date, targeted antiviral interventions against COVID-19 are limited. The spectrum of SARS-CoV-2 infection ranges from asymptomatic to fatal disease. However, the reasons for varying outcomes to SARS-CoV-2 infection are yet to be elucidated. Here we show that an endogenously activated interferon lambda (IFNλ1) pathway leads to resistance against SARS-CoV-2 infection. Using a well-differentiated primary nasal epithelial cell (WD-PNEC) culture model derived from multiple adult donors, we discovered that susceptibility to SARS-CoV-2 infection, but not respiratory syncytial virus (RSV) infection, varied. One of four donors was resistant to SARS-CoV-2 infection. High baseline IFNλ1 expression levels and associated interferon stimulated genes correlated with resistance to SARS-CoV-2 infection. Inhibition of the JAK/STAT pathway in WD-PNECs with high endogenous IFNλ1 secretion resulted in higher SARS-CoV-2 titres. Conversely, prophylactic IFNλ treatment of WD-PNECs susceptible to infection resulted in reduced viral titres. An endogenously activated IFNλ response, possibly due to genetic differences, may be one explanation for the differences in susceptibility to SARS-CoV-2 infection in humans. Importantly, our work supports the continued exploration of IFNλ as a potential pharmaceutical against SARS-CoV-2 infection.

Comparison of SARS-CoV-2 Evolution in Paediatric Primary Airway Epithelial Cell Cultures Compared with Vero-Derived Cell Lines.

SARS-CoV-2 can efficiently infect both children and adults, albeit with morbidity and mortality positively associated with increasing host age and presence of co-morbidities. SARS-CoV-2 continues to adapt to the human population, resulting in several variants of concern (VOC) with novel properties, such as Alpha and Delta. However, factors driving SARS-CoV-2 fitness and evolution in paediatric cohorts remain poorly explored. Here, we provide evidence that both viral and host factors co-operate to shape SARS-CoV-2 genotypic and phenotypic change in primary airway cell cultures derived from children. Through viral whole-genome sequencing, we explored changes in genetic diversity over time of two pre-VOC clinical isolates of SARS-CoV-2 during passage in paediatric well-differentiated primary nasal epithelial cell (WD-PNEC) cultures and in parallel, in unmodified Vero-derived cell lines. We identified a consistent, rich genetic diversity arising in vitro, variants of which could rapidly rise to near fixation within two passages. Within isolates, SARS-CoV-2 evolution was dependent on host cells, with paediatric WD-PNECs showing a reduced diversity compared to Vero (E6) cells. However, mutations were not shared between strains. Furthermore, comparison of both Vero-grown isolates on WD-PNECs disclosed marked growth attenuation mapping to the loss of the polybasic cleavage site (PBCS) in Spike, while the strain with mutations in Nsp12 (T293I), Spike (P812R) and a truncation of Orf7a remained viable in WD-PNECs. Altogether, our work demonstrates that pre-VOC SARS-CoV-2 efficiently infects paediatric respiratory epithelial cells, and its evolution is restrained compared to Vero (E6) cells, similar to the case of adult cells. We highlight the significant genetic plasticity of SARS-CoV-2 while uncovering an influential role for collaboration between viral and host cell factors in shaping viral evolution and ultimately fitness in human respiratory epithelium.

Progression from acute to chronic hepatitis B is more common in older adults.

PURPOSE: The rate of progression of acute Hepatitis B (HBV) to chronic disease is quoted as <10%. The purpose of this study was to determine the rate of progression from acute to chronic HBV in Northern Ireland (NI), assessing the influence of age, gender and biochemical parameters. METHODS: All "acute" HBV cases diagnosed in NI between 2011 and 2015 were reviewed. Inclusion criteria: 1). positive HBsAg and positive HBV core IgM; 2). in the absence of positive HBV core IgM, positive HBsAg with a recent negative HBsAg. Patient age, HBsAg, HBV core IgM, peak bilirubin and peak ALT were recorded, along with date and result of repeat HbsAg testing. Mann-Whitney U test was used to compare mean age, peak ALT and bilirubin between clearing and non-clearing groups. Fisher's exact test was used to compare progression to chronicity according to gender and age less than or greater than 50yrs. RESULTS: Of 80 identified cases, 4 incorrectly categorised cases were excluded. Of the remaining 76, (15 female (mean age 37.27yr), 61 male (mean age 47.39yr)) follow-up data was available for 71 patients (15 female (mean age 37.27yr), 56 male (48.59yr)). All female patients cleared HBV. 42 of 61 males cleared HBV (p=0.0313).Overall the chronicity rate was 18.42% The mean age of those clearing the virus was 43.88 years, versus 55.64 years for those going on to develop chronic HBV (Mann-Whitney U test, z= -2.68, p=0.0037). Clearance rate was 83.72% in patients aged <50yrs and 63.64% in patients 50yrs (p=0.0068).Mean peak ALT (U/L) and peak bilirubin (µmol/L) for the clearing group were 2130 and 174 respectively compared to 656 and 100 for the non-clearing group (z= -3.51, p=0.0002, z= -2.35, p=0.009). CONCLUSION: Our results suggest a higher than expected rate of progression from acute to chronic HBV with a significantly higher risk for those over 50yrs. This suggests a need to revise information provided to older patients with acute HBV regarding the likelihood of progression.

Socio-economic status and lifestyle factors are associated with achalasia risk: A population-based case-control study.

AIM: To evaluate the association between various lifestyle factors and achalasia risk. METHODS: A population-based case-control study was conducted in Northern Ireland, including n = 151 achalasia cases and n = 117 age- and sex-matched controls. Lifestyle factors were assessed via a face-to-face structured interview. The association between achalasia and lifestyle factors was assessed by unconditional logistic regression, to produce odds ratios (OR) and 95% confidence interval (CI). RESULTS: Individuals who had low-class occupations were at the highest risk of achalasia (OR = 1.88, 95%CI: 1.02-3.45), inferring that high-class occupation holders have a reduced risk of achalasia. A history of foreign travel, a lifestyle factor linked to upper socio-economic class, was also associated with a reduced risk of achalasia (OR = 0.59, 95%CI: 0.35-0.99). Smoking and alcohol consumption carried significantly reduced risks of achalasia, even after adjustment for socio-economic status. The presence of pets in the house was associated with a two-fold increased risk of achalasia (OR = 2.00, 95%CI: 1.17-3.42). No childhood household factors were associated with achalasia risk. CONCLUSION: Achalasia is a disease of inequality, and individuals from low socio-economic backgrounds are at highest risk. This does not appear to be due to corresponding alcohol and smoking behaviours. An observed positive association between pet ownership and achalasia risk suggests an interaction between endotoxin and viral infection exposure in achalasia aetiology.

Lack of association between serological evidence of past Coxiella burnetii infection and incident ischaemic heart disease: nested case-control study.

BACKGROUND: Coxiella burnetii causes the common worldwide zoonotic infection, Q fever. It has been previously suggested that patients who had recovered from acute Q fever (whether symptomatic or otherwise) may be at increased risk of ischaemic heart disease. We undertook this study to determine if past infection with Coxiella burnetii, the aetiological agent of Q fever, is a risk factor for the subsequent development of ischaemic heart disease. METHODS: A nested case-control study within the Prospective Epidemiological Study of Myocardial Infarction (PRIME). The PRIME study is a cohort study of 10,593 middle-aged men undertaken in France and Northern Ireland in the 1990s. A total of 335 incident cases of ischaemic heart disease (IHD) were identified and each case was matched to 2 IHD free controls. Q fever seropositivity was determined using a commercial IgG ELISA method. RESULTS: Seroprevalence of Q fever in the controls from Northern Ireland and France were 7.8% and 9.0% respectively. No association was seen between seropositivity and age, smoking, lipid levels, or inflammatory markers. The unadjusted odds ratio (95% CI) for Q fever seropositivity in cases compared to controls was 0.95 (0.59, 1.57). The relationship was substantially unaltered following adjustment for cardiovascular risk factors and potential confounders. CONCLUSION: Serological evidence of past infection with C. burnetii was not found to be associated with an increased risk of IHD.

A touchdown nucleic acid amplification protocol as an alternative to culture backup for immunofluorescence in the routine diagnosis of acute viral respiratory tract infections.

BACKGROUND: Immunofluorescence and virus culture are the main methods used to diagnose acute respiratory virus infections. Diagnosing these infections using nucleic acid amplification presents technical challenges, one of which is facilitating the different optimal annealing temperatures needed for each virus. To overcome this problem we developed a diagnostic molecular strip which combined a generic nested touchdown protocol with in-house primer master-mixes that could recognise 12 common respiratory viruses. RESULTS: Over an 18 month period a total of 222 specimens were tested by both immunofluorescence and the molecular strip. The specimens came from 103 males (median age 3.5 y), 80 females (median age 9 y) and 5 quality assurance scheme specimens. Viruses were recovered from a number of specimen types including broncho-alveolar lavage, nasopharyngeal secretions, sputa, post-mortem lung tissue and combined throat and nasal swabs. Viral detection by IF was poor in sputa and respiratory swabs. A total of 99 viruses were detected in the study from 79 patients and 4 quality control specimens: 31 by immunofluorescence and 99 using the molecular strip. The strip consistently out-performed immunofluorescence with no loss of diagnostic specificity. CONCLUSIONS: The touchdown protocol with pre-dispensed primer master-mixes was suitable for replacing virus culture for the diagnosis of respiratory viruses which were negative by immunofluorescence. Results by immunofluorescence were available after an average of 4-12 hours while molecular strip results were available within 24 hours, considerably faster than viral culture. The combined strip and touchdown protocol proved to be a convenient and reliable method of testing for multiple viruses in a routine setting.

Pneumocystis jirovecii multilocus genotyping profiles in Northern Ireland.

Pneumocystis jirovecii causes pneumonia, a severe opportunistic infection in immunosuppressed patients that has both person-to-person airborne transmission and environmental transmission as important routes of infection. An increasing incidence of P. jirovecii in Northern Ireland prompted a detailed epidemiological and molecular review that included enhanced surveillance on all lower respiratory specimens. Genotyping of these P. jirovecii positive specimens was undertaken using multiple locus sequence typing (MLST) targeting known variable regions of the P. jirovecii genome. Multiple circulating types were found among all patient risk categories. However, a predominance of one MLST type was found in a P. jirovecii outbreak amongst the renal transplant population. Our results demonstrate the diversity of P. jirovecii strains amongst the local immunosuppressed cohort and highlight the importance of genotyping in the investigation of common sources of P. jirovecii amongst immunosuppressed patients.

Acute respiratory distress syndrome caused by Mycoplasma pneumoniae diagnosed by polymerase chain reaction.

Mycoplasma pneumoniae (M. pneumoniae) is a common pathogen in cases of atypical pneumonia. Most individuals with Mycoplasma pneumonia run a benign course, with non-specific symptoms of malaise, fever and non-productive cough that usually resolve with no long-term sequelae. Acute lung injury is not commonly seen in Mycoplasma pneumonia. We report a case of acute respiratory distress syndrome cause by M. pneumoniae diagnosed by quantitative real-time polymerase chain reaction (RT-PCR).

Rising incidence of Pneumocystis jirovecii pneumonia suggests iatrogenic exposure of immune-compromised patients may be becoming a significant problem.

Against a background of point-source outbreaks of Pneumocystis pneumonia (PCP) in renal transplant units in Europe, we undertook a retrospective 3 year observational review of PCP in Northern Ireland. This showed an unexpected increase in incidence, with a mortality rate of 30 %. Fifty-one cases were confirmed compared to 10 cases confirmed in the preceding 7 years. Where undiagnosed HIV infection had previously been the main risk factor for PCP, this was now equally matched by chemotherapy for haematological and non-haematological malignancy and immune suppression for a range of autoimmune conditions. Congenital immunodeficiency and transplantation were less common predisposing factors, but renal grafts also showed a rising incidence. Asymptomatic carriage was uncommon. At presentation both upper and lower respiratory samples were of equal use in establishing the diagnosis, and treatment resulted in rapid clearance. These data suggest the need for considering PCP in at-risk patients, reviewing its mode of acquisition and whether iatrogenic colonization is a treatable pre-condition.

Development and clinical validation of a loop-mediated isothermal amplification method for the rapid detection of Neisseria meningitidis.

Loop-mediated isothermal amplification (LAMP) is an innovative technique that allows the rapid detection of target nucleic acid sequences under isothermal conditions without the need for complex instrumentation. The development, optimization, and clinical validation of a LAMP assay targeting the ctrA gene for the rapid detection of capsular Neisseria meningitidis were described. Highly specific detection of capsular N. meningitidis type strains and clinical isolates was demonstrated, with no cross-reactivity with other Neisseria spp. or with a comprehensive panel of other common human pathogens. The lower limit of detection was 6 ctrA gene copies detectable in 48 min, with positive reactions readily identifiable visually via a simple color change. Higher copy numbers could be detected in as little as 16 min. When applied to a total of 394 clinical specimens, the LAMP assay in comparison to a conventional TaqMan® based real-time polymerase chain reaction system demonstrated a sensitivity of 100% and a specificity of 98.9% with a κ coefficient of 0.942. The LAMP method represents a rapid, sensitive, and highly specific technique for the detection of N. meningitidis and has the potential to be used as a point-of-care molecular test and in resource-poor settings.

Interlaboratory comparison of real-time polymerase chain reaction methods to detect Coxiella burnetii, the causative agent of Q fever.

The bacterium Coxiella burnetii, which has a wide host range, causes Q fever. Infection with C. burnetii can cause abortions, stillbirth, and the delivery of weak offspring in ruminants. Coxiella burnetii infection is zoonotic, and in human beings it can cause chronic, potentially fatal disease. Real-time polymerase chain reaction (PCR) is increasingly being used to detect the organism and to aid in diagnosis both in human and animal cases. Many different real-time PCR methods, which target different genes, have been described. To assess the comparability of the C. burnetii real-time PCR assays in use in different European laboratories, a panel of nucleic acid extracts was dispatched to 7 separate testing centers. The testing centers included laboratories from both human and animal health agencies. Each laboratory tested the samples using their in-house real-time PCR methods. The results of this comparison show that the most common target gene for real-time PCR assays is the IS1111 repeat element that is present in multiple copies in the C. burnetii genome. Many laboratories also use additional real-time PCR tests that target single-copy genes. The results of the current study demonstrate that the assays in use in the different laboratories are comparable, with general agreement of results for the panel of samples.

Influenza: a virus of our times.

Viruses are successful and omnipresent. Influenza A is a particularly important virus of humans. The article reviews the 2009 emergence of the pandemic influenza A virus, focusing on the potential origin of the virus and the distinctive clinical and epidemiological impact of the 2009 pandemic.