Trypanosoma cruzi screening in people living with HIV in the UK.

People living with HIV (PLWH) are at higher risk of reactivation of Chagas disease, a neglected tropical disease, caused by Trypanosoma cruzi. There are no data from UK HIV clinics on the prevalence of T. cruzi. We implemented T. cruzi screening at our clinic as part of routine care for PLWH with epidemiological risk factors. Among 86 patients screened, none had positive serology: one seropositive patient was identified due to increased clinician awareness. Implementing T. cruzi screening as part of routine clinical care was feasible, though labour intensive and identified at-risk individuals.

Treatment Failure in a UK Malaria Patient Harboring Genetically Variant Plasmodium falciparum From Uganda With Reduced In Vitro Susceptibility to Artemisinin and Lumefantrine.

BACKGROUND: Recent cases of clinical failure in malaria patients in the United Kingdom (UK) treated with artemether-lumefantrine have implications for malaria chemotherapy worldwide. METHODS: Parasites were isolated from an index case of confirmed Plasmodium falciparum treatment failure after standard treatment, and from comparable travel-acquired UK malaria cases. Drug susceptibility in vitro and genotypes at 6 resistance-associated loci were determined for all parasite isolates and compared with clinical outcomes for each parasite donor. RESULTS: A traveler, who returned to the UK from Uganda in 2022 with Plasmodium falciparum malaria, twice failed treatment with full courses of artemether-lumefantrine. Parasites from the patient exhibited significantly reduced susceptibility to artemisinin (ring-stage survival, 17.3% [95% confidence interval {CI}, 13.6%-21.1%]; P < .0001) and lumefantrine (effective concentration preventing 50% of growth = 259.4 nM [95% CI, 130.6-388.2 nM]; P = .001). Parasite genotyping identified an allele of pfk13 encoding both the A675V variant in the Pfk13 propeller domain and a novel L145V nonpropeller variant. In vitro susceptibility testing of 6 other P. falciparum lines of Ugandan origin identified reduced susceptibility to artemisinin and lumefantrine in 1 additional line, also from a 2022 treatment failure case. These parasites did not harbor a pfk13 propeller domain variant but rather the novel nonpropeller variant T349I. Variant alleles of pfubp1, pfap2mu, and pfcoronin were also identified among the 7 parasite lines. CONCLUSIONS: We confirm, in a documented case of artemether-lumefantrine treatment failure imported from Uganda, the presence of pfk13 mutations encoding L145V and A675V. Parasites with reduced susceptibility to both artemisinin and lumefantrine may be emerging in Uganda.

Medical management of cystic echinococcosis.

PURPOSE OF REVIEW: Cystic echinococcosis is a neglected zoonosis for which humans are dead end hosts. It is not only widely distributed in sheep rearing areas of low-income and middle-income countries but also has a significant presence in wealthy countries, for example, in Europe. It results in considerable morbidity, and its current management is far from optimal. Medical management is with a benzimidazole, with the addition of praziquantel under some circumstances. RECENT FINDINGS: Interest in mebendazole as an anticancer drug has stimulated research into new drug formulations to improve bioavailability and possibly reduce inter-individual variability in in-vivo drug levels, which may help its activity against cystic echinococcosis. Further evidence to support administration of albendazole with a fatty meal has been provided. GlaxoSmithKilne (GSK) has agreed to extend its albendazole donation programme to include echinococcosis. The search for new drugs has focussed on natural products, such as essential oils and on repurposing of existing drugs licensed for human use against other conditions. SUMMARY: The medical treatment of cystic echinococcosis remains sorely neglected, with no new drugs for almost 40 years. We need a better understanding of how to use the drugs we do have, whilst seeking new ones. Drug repurposing may be the best pathway.

Diagnosis and Clinical Management of Chagas Disease: An Increasing Challenge in Non-Endemic Areas.

Chagas disease (CD) is caused by the parasite Trypanosoma cruzi, and it is endemic in Central, South America, Mexico and the South of the United States. It is an important cause of early mortality and morbidity, and it is associated with poverty and stigma. A third of the cases evolve into chronic cardiomyopathy and gastrointestinal disease. The infection is transmitted vertically and by blood/organ donation and can reactivate with immunosuppression. Case identification requires awareness and screening programmes targeting the population at risk (women in reproductive age, donors, immunocompromised patients). Treatment with benznidazole or nifurtimox is most effective in the acute phase and prevents progression to chronic phase when given to children. Treating women antenatally reduces but does not eliminate vertical transmission. Treatment is poorly tolerated, contraindicated during pregnancy, and has little effect modifying the disease in the chronic phase. Screening is easily performed with serology. Migration has brought the disease outside of the endemic countries, where the transmission continues vertically and via blood and tissue/organ donations. There are more than 32 million migrants from Latin America living in non-endemic countries. However, the infection is massively underdiagnosed in this setting due to the lack of awareness by patients, health authorities and professionals. Blood and tissue donation screening policies have significantly reduced transmission in endemic countries but are not universally established in the non-endemic setting. Antenatal screening is not commonly done. Other challenges include difficulties accessing and retaining patients in the healthcare system and lack of specific funding for the interventions. Any strategy must be accompanied by education and awareness campaigns directed to patients, professionals and policy makers. The involvement of patients and their communities is central and key for success and must be sought early and actively. This review proposes strategies to address challenges faced by non-endemic countries.

A Rapid FRET Real-Time PCR Protocol for Simultaneous Quantitative Detection and Discrimination of Human Plasmodium Parasites.

Malaria is the most important parasitic disease worldwide, and accurate diagnosis and treatment without delay are essential for reducing morbidity and mortality, especially in P. falciparum malaria. Real-time PCR is highly sensitive and highly specific, therefore an excellent diagnostic tool for laboratory detection and species-specific diagnosis of malaria, especially in non-endemic regions where experience in microscopic malaria diagnostics is limited. In contrast to many other real-time PCR protocols, our new fluorescence resonance energy transfer-based real-time PCR (FRET-qPCR) allows the quantitative and species-specific detection of all human Plasmodium spp. in one run. Species identification is based on single nucleotide polymorphisms (SNPs) within the MalFL probe, detectable by melting curve analysis. A significant advantage of our FRET-qPCR is the short turn-around time of less than two hours, including DNA extraction, which qualifies it for routine diagnostics. Rapid and reliable species-specific malaria diagnosis is important, because treatment is species-dependent. Apart from first-line diagnosis, the quantitative results of our new FRET-qPCR can be helpful in therapy control, to detect early treatment failure. Graphic abstract.

British Society for Haematology guidelines for the laboratory diagnosis of malaria.

The laboratory diagnosis of malaria depends on skilled examination of well-stained thick and thin blood films. Rapid diagnostic tests are a useful supplement and the use of nucleic acid-based testing in diagnostic laboratories should also be considered. These British Society for Haematology guidelines update the 2003 guidelines for malaria diagnosis. Training, quality control, incidental diagnosis, differential diagnosis and reference laboratory referral are considered.

Surveillance of leishmaniasis cases from 15 European centres, 2014 to 2019: a retrospective analysis.

BackgroundSurveillance of human leishmaniasis in Europe is mostly limited to country-specific information from autochthonous infections in the southern part. As at the end of 2021, no integrated analysis has been performed for cases seen across centres in different European countries.AimTo provide a broad perspective on autochthonous and imported leishmaniasis cases in endemic and non-endemic countries in Europe.MethodsWe retrospectively collected records from cutaneous, mucosal and visceral leishmaniasis cases diagnosed in 15 centres between 2014 and 2019. Centres were located in 11 countries: Belgium, France, Germany, Italy, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Data on country of infection, reason for travelling, infecting species, age and sex were analysed.ResultsWe obtained diagnostic files from 1,142 cases, of which 76%, 21% and 3% had cutaneous, visceral, and mucosal disease, respectively. Of these, 68% were men, and 32% women, with the median age of 37 years (range: 0-90) at diagnosis. Visceral leishmaniasis was mainly acquired in Europe (88%; 167/190), while cutaneous leishmaniasis was primarily imported from outside Europe (77%; 575/749). Sixty-two percent of cutaneous leishmaniasis cases from outside Europe were from the Old World, and 38% from the New World. Geographic species distribution largely confirmed known epidemiology, with notable exceptions.ConclusionsOur study confirms previous reports regarding geographic origin, species, and traveller subgroups importing leishmaniasis into Europe. We demonstrate the importance of pooling species typing data from many centres, even from areas where the aetiology is presumably known, to monitor changing epidemiology.

Validation of a novel FRET real-time PCR assay for simultaneous quantitative detection and discrimination of human Plasmodium parasites.

Increasing numbers of travelers returning from endemic areas, migrants, and refugees have led to a significant rise in the number of imported malaria cases in non-endemic countries. Real- time PCR serves as an excellent diagnostic tool, especially in regions where experience in microscopy is limited. A novel fluorescence resonance energy transfer-based real-time PCR (FRET-qPCR) was developed and evaluated using 56 reference samples of the United Kingdom National External Quality Assessment Service (UK NEQAS) for molecular detection of malaria, including P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi. Species identification is based on single nucleotide polymorphisms (SNPs) within the genome where the MalLC640 probe binds, lowering the melting temperature in the melting curve analysis. The novel FRET-qPCR achieved 100% (n = 56) correct results, compared to 96.43% performing nested PCR. The high sensitivity, with a calculated limit of detection of 199.97 parasites/mL blood for P. falciparum, is a significant advantage, especially if low-level parasitemia has to be ruled out. Even mixed infections of P. falciparum with P. vivax or P. ovale, respectively, were detected. In contrast to many other real-time PCR protocols, this novel FRET-qPCR allows the quantitative and species-specific detection of Plasmodium spp. in one single run. Solely, P. knowlesi was detected but could not be differentiated from P. vivax. The turnaround time of this novel FRET-qPCR including DNA extraction is less than two hours, qualifying it for routine clinical applications, including treatment monitoring.

Predictors of aetiology and outcomes of acute gastrointestinal illness in returning travellers: a retrospective cohort analysis.

BACKGROUND: Gastrointestinal illness is a major cause of morbidity in travellers and is a common reason for presentation to healthcare services on return. Whilst the aetiology of imported gastrointestinal disease is predominantly infectious, outcomes are variable due to a range of phenomena such as post-infectious irritable bowel syndrome, drug resistance and occult pathology (both infectious and non-infectious). Previous studies have focussed on predictors of aetiology of gastrointestinal disease in travellers; we present a retrospective study combining both aetiological and early outcome data in a large cohort of returned travellers. METHOD: We identified 1450 patients who attended our post-travel walk-in clinic with gastrointestinal symptoms between 2010 and 2016. Demographic, travel, clinical and laboratory data was collected through case note review. Logistic regression analysis to examine correlates of aetiology and outcome were performed in R (CRAN Project 2017). RESULTS: Of 1450 patients in our cohort 153 reported bloody diarrhoea and 1081 (74.6%) reported non-bloody diarrhoea. A definitive microbiological diagnosis was made in 310 (20.8%) of which 137 (9.4%) had a parasite identified and 111 (7.7%) had a bacterial cause identified. Factors associated with a parasitological diagnosis included history of travel to South Asia (aOR = 2.55; 95%CI 1.75-3.70, p < 0.0001) and absence of bloody diarrhoea (aOR = 0.22; 95%CI 0.066-0.53, p < 0.005). Factors associated with a bacteriological diagnosis included male gender (aOR = 1.69; 95%CI 1.10-2.62, p < 0.05), an age < 37 years on presentation (aOR = 2.04; 95%CI 1.25-3.43, p < 0.01), white cells on stool microscopy (aOR = 3.52; 95%CI 2.09-5.86, p < 0.0001) and a C-reactive protein level of >5iu/dL (aOR = 4.68; 95%CI 2.91-7.72, p < 0.0001). The majority (1235/1450, 82.6%) reported full symptomatic resolution by the first follow up visit; factors associated with lack of symptomatic resolution included female gender (aOR = 1.45 95%CI 1.06-1.99, p < 0.05), dysenteric diarrhoea (aOR = 2.14 (95%CI 1.38-3.25, p < 0.0005) and elevated peripheral leukocyte count (aOR = 1.58 95%CI 1.02-2.40, p < 0.05). CONCLUSIONS: In a cohort of returned travellers, we were able to identify multiple factors that are correlated with both aetiology and outcome of imported gastrointestinal syndromes. We predict these data will be valuable in the development of diagnostic and therapeutic pathways for patients with imported gastrointestinal infections.

The effectiveness of anti-inflammatory and anti-seizure medication for individuals with single enhancing lesion neurocysticercosis: A meta-analysis and expert group-based consensus recommendations.

Single brain enhancing lesions (SEL) are the most common presentation of neurocysticercosis (NCC) observed on neuroimaging in people presenting with epileptic seizures not only on the Indian sub-continent and in travelers returning from cysticercosis-endemic regions, but are also present in other parts of the world. The aim of this study, which consisted of a systematic review (CRD42019087665), a meta-analysis and an expert group consultation, was to reach consensus on the best anti-seizure medication and anti-inflammatory treatment for individuals with SEL NCC. Standard literature review methods were used. The Cochrane risk of bias tool was used and random effects model meta-analyses were performed. The quality of the body of evidence was rated using GRADE tables. The expert committee included 12 gender and geographically balanced members and recommendations were reached by applying the GRADE framework for guideline development. The 1-1.5-year cumulative incidence of seizure recurrence, cyst resolution or calcification following anti-seizure medication (ASM) withdrawal was not statistically different between ASM of 6, 12 or 24 months. In contrast, in persons whose cyst calcified post treatment, longer ASM decreased seizure recurrence. The cumulative incidence ratio (CIR) 1-1.5 years after stopping ASM was 1.79 95% CI: (1.00, 3.20) for patients given 6 versus 24 months treatment. Anti-inflammatory treatment with corticosteroids in patients treated with ASM compared to patients treated with ASM only showed a statistically significant beneficial effect on seizure reduction (CIR 0.44, 95% CI 0.23, 0.85) and cyst resolution (CIR 1.37, 95%CI: 1.07, 1.75). Our results indicate that ASM in patients with SEL NCC whose cysts resolved can be withdrawn, while patients whose cysts calcified seem to benefit from prolonged anti-seizure medication. Additional corticosteroid treatment was found to have a beneficial effect both on seizure reduction and cyst resolution.

Performance of a fully-automated system on a WHO malaria microscopy evaluation slide set.

BACKGROUND: Manual microscopy remains a widely-used tool for malaria diagnosis and clinical studies, but it has inconsistent quality in the field due to variability in training and field practices. Automated diagnostic systems based on machine learning hold promise to improve quality and reproducibility of field microscopy. The World Health Organization (WHO) has designed a 55-slide set (WHO 55) for their External Competence Assessment of Malaria Microscopists (ECAMM) programme, which can also serve as a valuable benchmark for automated systems. The performance of a fully-automated malaria diagnostic system, EasyScan GO, on a WHO 55 slide set was evaluated. METHODS: The WHO 55 slide set is designed to evaluate microscopist competence in three areas of malaria diagnosis using Giemsa-stained blood films, focused on crucial field needs: malaria parasite detection, malaria parasite species identification (ID), and malaria parasite quantitation. The EasyScan GO is a fully-automated system that combines scanning of Giemsa-stained blood films with assessment algorithms to deliver malaria diagnoses. This system was tested on a WHO 55 slide set. RESULTS: The EasyScan GO achieved 94.3 % detection accuracy, 82.9 % species ID accuracy, and 50 % quantitation accuracy, corresponding to WHO microscopy competence Levels 1, 2, and 1, respectively. This is, to our knowledge, the best performance of a fully-automated system on a WHO 55 set. CONCLUSIONS: EasyScan GO's expert ratings in detection and quantitation on the WHO 55 slide set point towards its potential value in drug efficacy use-cases, as well as in some case management situations with less stringent species ID needs. Improved runtime may enable use in general case management settings.

Delayed diagnosis of spinal cord schistosomiasis in a non-endemic country: A tertiary referral centre experience.

BACKGROUND: Neuroschistosomiasis is a severe complication of schistosomiasis, triggered by the local immune reaction to egg deposition, with spinal cord involvement the most well recognised form. Early treatment with praziquantel and high dose steroids leads to a reduction of neurological sequelae. The rarity of this condition in returning travellers to high income countries can result in delayed diagnosis and treatment. We aimed to evaluate the diagnosis and management of neuroschistosomiasis in a UK national referral centre. MATERIALS/METHODS: A retrospective review of confirmed clinical cases of spinal schistosomiasis referred to the Hospital for Tropical Diseases, UK, between January 2016 and January 2020 was undertaken. Electronic referral records were interrogated and patient demographic, clinical, laboratory, and radiological data collected. RESULTS: Four cases of neuroschistosomiasis were identified. The median age at diagnosis was 28 (range 21 to 50) with three male patients. All patients had epidemiological risk factors for schistosomiasis based on travel history and freshwater exposure; two in Uganda (River Nile), one in Malawi and one in Nigeria. All patients presented with features of transverse myelitis including back pain, leg weakness, paraesthesia and urinary dysfunction. The mean time from presentation to health services to definitive treatment was 42.5 days (range 16-74 days). Diagnosis was confirmed with CSF serology for schistosomiasis in all cases. Radiological features on MRI spine included enhancement focused predominantly in the lower thoracic spinal cord in three cases and the conus in one patient. All patients received a minimum of three days of oral praziquantel and high dose steroids. At three-month follow-up, one patient had complete resolution of symptoms and three had residual deficit; one patient was left with urinary and faecal incontinence, another had urinary retention, and the final patient has persistent leg pains and constipation. CONCLUSION: We observed a marked delay in diagnosis of neuroschistosomiasis in a non-endemic country. We advocate undertaking a thorough travel history, early use of imaging and CSF schistosomal serology to ensure early diagnosis of neuroschistosomiasis in patients presenting with consistent symptoms. If schistosomal diagnostics are not immediately available, presumptive treatment under the guidance of a tropical medicine specialist should be considered to minimize the risk of residual disability. We advocate for consensus guidelines to be produced and reporting to be performed in a uniform way for patients with spinal schistosomiasis.

Utility of an infectious and tropical disease histopathology diagnostic review service.

AIM: To assess the utility of a London-based infectious and tropical disease histopathology diagnostic review service. METHODS: The original and specialist review histopathology reports of 457 samples from over 3 years of referrals were compared retrospectively. RESULTS: Overall 329 (72.0%) showed no significant difference; 34 (7.4%) showed a non-clinically significant difference; and 94 (20.6%) showed a clinically significant difference. Of the 94 clinically significant discrepancies, 46 (48.9%) were incorrectly suspected infections; 19 (20.2%) were missed infections; 8 (8.5%) were different infections; and in 20 (21.3%), the specialist review yielded more specific identification of an organism or a more correct assessment of its viability. CONCLUSIONS: A review of histopathology cases by an infectious disease (ID) histopathology referral centre has yielded a 20.6% clinically significant error rate. Measures to improve training in ID histopathology in the UK are discussed.

Chagas disease in the United Kingdom: A review of cases at the Hospital for Tropical Diseases London 1995-2018. The current state of detection of Chagas disease in the UK.

BACKGROUND: Chagas disease (CD), is a parasitic disease endemic in Latin America. Presentation in non-endemic areas is either in the asymptomatic indeterminate phase or the chronic phase with cardiac and/or gastrointestinal complications. METHODS: The Hospital for Tropical Diseases (HTD) based in central London, provides tertiary care for the management of CD. We reviewed all cases managed at this centre between 1995 and 2018. RESULTS: Sixty patients with serologically proven CD were identified. Most were female (70%), with a median age at diagnosis of 41 years. Three quarters of the patients were originally from Bolivia. 62% of all patients were referred to the HTD by their GP. Nearly half of the patients were asymptomatic (47%). Twelve patients had signs of cardiac involvement secondary to CD. Evidence of gastrointestinal damage was established in three patients. Treatment was provided at HTD for 31 patients (47%). Most patients (29) received benznidazole, five of them did not tolerate the course and were switched to nifurtimox. Of the seven patients receiving this second line drug, five completed treatment, whilst two interrupted it due to side effects. CONCLUSIONS: Despite the UK health system having all the resources required to diagnose, treat and follow up cases, there is lack of awareness of CD, such that the vast majority of cases remain undiagnosed and therefore do not receive treatment. We propose key interventions to improve the detection and management of this condition in the UK, especially in pregnant women and neonates.

WHO malaria nucleic acid amplification test external quality assessment scheme: results of distribution programmes one to three.

BACKGROUND: The World Health Organization (WHO) recommends parasite-based diagnosis of malaria. In recent years, there has been surge in the use of various kinds of nucleic-acid amplification based tests (NAATs) for detection and identification of Plasmodium spp. to support clinical care in high-resource settings and clinical and epidemiological research worldwide. However, these tests are not without challenges, including lack (or limited use) of standards and lack of reproducibility, due in part to variation in protocols amongst laboratories. Therefore, there is a need for rigorous quality control, including a robust external quality assessment (EQA) scheme targeted towards malaria NAATs. To this effect, the WHO Global Malaria Programme worked with the UK National External Quality Assessment Scheme (UK NEQAS) Parasitology and with technical experts to launch a global NAAT EQA scheme in January 2017. METHODS: Panels of NAAT EQA specimens containing five major species of human-infecting Plasmodium at various parasite concentrations and negative samples were created in lyophilized blood (LB) and dried blood spot (DBS) formats. Two distributions per year were sent, containing five LB and five DBS specimens. Samples were tested and validated by six expert referee laboratories prior to distribution. Between 37 and 45 laboratories participated in each distribution and submitted results using the online submission portal of UK NEQAS. Participants were scored based on their laboratory's stated capacity to identify Plasmodium species, and individual laboratory reports were sent which included performance comparison with anonymized peers. RESULTS: Analysis of the first three distributions revealed that the factors that most significantly affected performance were sample format (DBS vs LB), species and parasite density, while laboratory location and the reported methodology used (type of nucleic acid extraction, amplification, or DNA vs RNA target) did not significantly affect performance. Referee laboratories performed better than non-referee laboratories. CONCLUSIONS: Globally, malaria NAAT assays now inform a range of clinical, epidemiological and research investigations. EQA schemes offer a way for laboratories to assess and improve their performance, which is critical to safeguarding the reliability of data and diagnoses especially in situations where various NAAT methodologies and protocols are in use.

High Prevalence of Strongyloides among South Asian Migrants in Primary Care-Associations with Eosinophilia and Gastrointestinal Symptoms.

Gastrointestinal (GI) symptoms are a frequent reason for primary care consultation, and common amongst patients with strongyloidiasis. We conducted a prospective cohort and nested case control study in East London to examine the predictive value of a raised eosinophil count or of GI symptoms, for Strongyloides infection in South Asian migrants. We included 503 patients in the final analyses and all underwent a standardised GI symptom questionnaire, eosinophil count and Strongyloides serology testing. Positive Strongyloides serology was found in 33.6% in the eosinophilia cohort against 12.5% in the phlebotomy controls, with adjusted odds ratio of 3.54 (95% CI 1.88-6.67). In the GI symptoms cohort, 16.4% were seropositive but this was not significantly different compared with controls, nor were there associations between particular symptoms and Strongyloidiasis. Almost a third (35/115) of patients with a positive Strongyloides serology did not have eosinophilia at time of testing. Median eosinophil count declined post-treatment from 0.5 cells × 109/L (IQR 0.3-0.7) to 0.3 (0.1-0.5), p < 0.001. We conclude Strongyloides infection is common in this setting, and the true symptom burden remains unclear. Availability of ivermectin in primary care would improve access to treatment. Further work should clarify cost-effectiveness of screening strategies for Strongyloides infection in UK migrant populations.

Strongyloides, HTLV-1 and small bowel obstruction.

An 81-year-old Jamaican man who has been resident in the UK for many years presented with one week history of generalised abdominal pain, postprandial vomiting, anorexia, weight loss and abdominal distension. He was managed conservatively for acute small bowel obstruction. Investigations revealed a duodenal stricture. Live Strongyloides stercoralis larvae were observed in stool samples and duodenal biopsy confirmed the presence of the parasite at multiple life cycle stages within the lamina propria. He was diagnosed with Strongyloides hyperinfection with underlying human T-cell lymphotropic virus type 1 and treated with a prolonged course of ivermectin with ongoing monitoring for relapse. This case demonstrates a rare but potentially fatal cause of small bowel obstruction.