CHANGING TRENDS IN THE DIAGNOSIS OF MALARIA AND TYPHOID FEVER

Malaria In tropical Africa, fever is commonly associated with malaria that was known variously as Roman fever,   marsh fever(Rocco 2003),  and whose name was derived from the Italian ‘Mal=bad, Aria=air.’(Prakash et al. 2013).    Malaria is caused by five species of the plasmodium parasite: P. falciparum, P. vivax, P.ovale, P. malariae and P. knowlesi all of which are transmitted by the female anopheles mosquito, which is the vector of the parasite. Over 2.4 billion people are at risk of P. falciparum infection, which results in about 300 to  500 million clinical episodes and 1million deaths annually (Bousema & Drakeley 2011). While about 2.9 billion persons are at risk for P. vivax infection with up to 300 million clinical episodes per year(Bousema & Drakeley 2011). A vast proportion of malaria morbidity occurs in sub-Saharan Africa, (SSA). However, there is substantial evidence that the intensity of malaria transmission in Africa is declining (Snow et al. 2012, Graz et al. 2011), and rapid malaria parasitemia tests are well distributed in endemic countries and easy to use (Graz et al. 2011).    Certain recent developments, however, are worth considering when assessing malaria burden and control.First, the discovery of Plasmodium falciparum with deleted histidine-rich repeat region of the histidine-rich-protein 2 and the evidence that parasites not detected by HRP2 lateral flow immunoassay(LFI) cause latent infection(Koita et al. 2012), is of extreme importance in endemic countries such as Sierra Leone, where HRP2  LFIs are predominantly used. LFIs have made malaria testing ubiquitous in sub-Saharan Africa, including in very remote areas. However, false negatives resulting from deleted hrp2 in certain P.falciparum may result in lower prevalence reports. The alternative dipstick to HRP2 LFIs is the Plasmodium lactate dehydrogenase (pLDH)-based LFI. However, in Sierra Leone, the use of pLDH LFIs is less common, and a similar trend exists in the other parts of Sub-Saharan Africa. LFIs were intended to be used primarily in resource-limited locations where expert microscopists are unavailable. So the use of LFIs is not routinely duplicated with smear results in many developing countries. This could be a setback for resource-poor settings.The use of point of care, multiplex molecular detection methods have been highlighted as a means of salvaging diagnosis in resource-poor countries, but cost remains a major limitation. Notwithstanding, PCR is emerging as most sensitive malaria diagnostic apart from rapid antigen tests. Antigens and DNA may persist in blood after parasite clearance through treatment.  A plausible alternative has sought sexual stages of malaria parasites representing a small fraction of parasites during infection(Tao et al. 2014), but which can also be detected in body fluids such as saliva. Prior evidence indicates that saliva is an excellent non-invasive candidate for rapid malaria testing (Fung et al. 2012), but this aspect of malaria diagnostics is still under development including rapid tests based on nano trap technology.There has been a renewed global commitment for malaria elimination and both symptomatic and asymptomatic malaria infections are critical for the elimination of malaria. Novel diagnosis of subclinical malaria targeting sexual stages of the parasite are emerging, but the best candidate for such diagnostics are those that could be adaptable to the resource-poor settings in Africa. One such candidate is the nano trap, saliva-based, malaria rapid test that is under development by Johns Hopkins(http://www.jhsph.edu/news/news-releases/2015/johns-hopkins-bloomberg-school-of-public-health-researchers-receive-grant-to-evaluate-malaria-detection-test.html). Typhoid Fever In the case of typhoid fever, there seems to be an over-diagnosis.  The gold standard for the diagnosis of typhoid is by blood culture, which has a sensitivity of 40-60%(Parry et al. 1999), but low-cost tests, mainly the widal test, are more adaptable to resource-poverty and are commonly used in resource-poor settings such as Sierra Leone. Widal tests have been in use for over 110 years, but the results are very controversial(Olopoenia & King 2000, Nga et al. 2012),  and the test suffers from low specificity in endemic countries probably as a result of an increase in population antibody levels (Clegg et al. 1994).A positive Widal test does not always denote the presence of typhoid fever. Apart from increased population antibody levels, there exist up to 40 cross-reacting antigens between Salmonella enterica serotype Typhi and other Enterobacteriaceae(Parry et al. 1999). Cross-reacting antigens could also be from malaria, brucellosis, dengue fever, chronic liver disease or endocarditis(Colle et al. 1996).Blood culture which is the gold standard is time-consuming and may delay treatment apart from its inherently low sensitivity.  Several typhoid dipsticks have been reported, but side-by-side independent assessments in endemic countries do not always yield the expected outcome.Polymerase chain reaction is currently a better option for diagnosing typhoid fever with same day result, but cost remains a big issue in countries that could be most in need. While suitable alternatives based on economic conditions of countries are sought, the cut-off value for the widal test requires evaluation and standardization. Having a wrong diagnosis at the point of care could lead to wrong clinical outcomes.

Rat-atouille: A Mixed Method Study to Characterize Rodent Hunting and Consumption in the Context of Lassa Fever

Lassa fever is a zoonotic hemorrhagic illness predominant in areas across Nigeria, Sierra Leone, Guinea, Liberia, and southern Mali. The reservoir of Lassa virus is the multimammate mouse (Mastomys natalensis), a highly commensal species in West Africa. Primary transmission to humans occurs through direct or indirect contact with rodent body fluids such as urine, feces, saliva, or blood. Our research draws together qualitative and quantitative methods to provide a fuller and more nuanced perspective on these varied points of human–animal contact. In this article, we focus on the hunting, preparation, and consumption of rodents as possible routes of exposure in Bo, Sierra Leone. We found that the consumption of rodents, including the reservoir species, is widespread and does not neatly tally against generational or gender lines. Further, we found that the reasons for rodent consumption are multifactorial, including taste preferences, food security, and opportunistic behavior. We argue that on certain topics, such as rodent consumption, establishing trust with communities, and using qualitative research methods, is key to investigate sensitive issues and situate them in their wider context. To conclude, we recommend ways to refine sensitization campaigns to account for these socio-cultural contexts

Extending the ‘social’: Anthropological contributions to the study of viral haemorrhagic fevers

Anthropology and the One-Health Agenda for VHF Emerging Viral Haemorrhagic Fevers (VHFs) offer a frontier for a “One-Health ” research agenda; the joined-up, or collaborative, effort of multiple disciplines to attain optimal health for people, animals, and the environment (e.g.

Multimodal imaging and spatial analysis of Ebola retinal lesions in 14 survivors of Ebola virus disease

Importance: Differentiation between Ebola retinal lesions and other retinal pathologies in West Africa is important, and the pathogenesis of Ebola retinal disease remains poorly understood. Objective: To describe the appearance of Ebola virus disease (EVD) retinal lesions using multimodal imaging to enable inferences on potential pathogenesis. Design, Setting, and Participants: This prospective case series study was carried out at 34 Military Hospital in Freetown, Sierra Leone. Ophthalmological images were analyzed from 14 consecutively identified survivors of EVD of Sierra Leonean origin who had identified Ebola retinal lesions. Main Outcomes and Measures: Multimodal imaging findings including ultra-widefield scanning laser ophthalmoscopy, fundus autofluorescence, swept-source optical coherence tomography (OCT), Humphrey visual field analysis, and spatial analysis. Results: The 14 study participants had a mean (SD) age of 37.1 (8.8) years; 6 (43%) were women. A total of 141 Ebola retinal lesions were observed in 22 of 27 eyes (81%) of these 14 survivors on ultra-widefield imaging. Of these, 41 lesions (29.1%) were accessible to OCT imaging. Retinal lesions were predominantly nonpigmented with a pale-gray appearance. Peripapillary lesions exhibited variable curvatures in keeping with the retinal nerve fiber layer projections. All lesions respected the horizontal raphe and spared the fovea. The OCT imaging demonstrated a V-shaped hyperreflectivity of the outer nuclear layer overlying discontinuities of the ellipsoid zone and interdigitation zone in the smaller lesions. Larger lesions caused a collapse of the retinal layers and loss of retinal thickness. Lesion shapes were variable, but sharp angulations were characteristic. Perilesional areas of dark without pressure (thinned ellipsoid zone hyporeflectivity) accompanied 125 of the 141 lesions (88.7%) to varying extents. Conclusions and Relevance: We demonstrate OCT evidence of localized pathological changes at the level of the photoreceptors in small lesions among survivors of EVD with retinal lesions. The relevance of associated areas of dark without pressure remains undetermined

Characterizing HIV-1 genetic subtypes and drug resistance mutations among children, adolescents and pregnant women in Sierra Leone

Human immunodeficiency virus (HIV) drug resistance (HIVDR) is widespread in sub-Saharan Africa. Children and pregnant women are particularly vulnerable, and laboratory testing capacity remains limited. We, therefore, used a cross-sectional design and convenience sampling to characterize HIV subtypes and resistance-associated mutations (RAMs) in these groups in Sierra Leone. In total, 96 children (age 2–9 years, 100% ART-experienced), 47 adolescents (age 10–18 years, 100% ART-experienced), and 54 pregnant women (>18 years, 72% ART-experienced) were enrolled. Median treatment durations were 36, 84, and 3 months, respectively, while the sequencing success rates were 45%, 70%, and 59%, respectively, among children, adolescents, and pregnant women. Overall, the predominant HIV-1 subtype was CRF02_AG (87.9%, 95/108), with minority variants constituting 12%. Among children and adolescents, the most common RAMs were M184V (76.6%, n = 49/64), K103N (45.3%, n = 29/64), Y181C/V/I (28.1%, n = 18/64), T215F/Y (25.0%, n = 16/64), and V108I (18.8%, n = 12/64). Among pregnant women, the most frequent RAMs were K103N (20.6%, n = 7/34), M184V (11.8%, n = 4/34), Y181C/V/I (5.9%, n = 2/34), P225H (8.8%, n = 3/34), and K219N/E/Q/R (5.9%, n = 2/34). Protease and integrase inhibitor-RAMs were relatively few or absent. Based on the genotype susceptibility score distributions, 73%, 88%, and 14% of children, adolescents, and pregnant women, respectively, were not susceptible to all three drug components of the WHO preferred first-line regimens per 2018 guidelines. These findings suggest that routine HIVDR surveillance and access to better ART choices may improve treatment outcomes in Sierra Leone.This research was funded by the Roe Green Travel Medicine and Global Health Award 2019 (Award Number J0628), University Hospitals Cleveland Medical Center (G.A.Y.), Instituto de Salud Carlos III and Fondo Europeo de Desarrollo Regional-FEDER, Red Española de Investigación en SIDA (RD16/0025/0026) (E.P.), Xunta Galicia-Fondo Social Europeo (IN606A-2016/023) (E.P.) and Fundación Biomédica Galicia Sur (E.P.)

The Ministry of Health and Sanitation, Sierra Leone - Public Health England (MOHS-PHE) Ebola Biobank.

During the Ebola outbreak in 2014-2015 in Sierra Leone, residual clinical specimens and accompanying data were collected from routine diagnostic testing in Public Health England (PHE) led laboratories. Most of the samples with all the accompanying data were transferred to PHE laboratories in the UK for curation by PHE.  The remainder have been kept securely in Sierra Leone. The biobank holds approximately 9955 samples of which 1108 tested positive for Ebola virus. Researchers from the UK and overseas, from academia, government other research organisations and commercial companies can submit proposals to the biobank to access and use the samples. The Ministry of Health and Sanitation in Sierra Leone (MOHS) retains ownership of the data and materials and is working with PHE and other researchers to develop and conduct a series of research projects that will inform future healthcare and public health strategies relating to Ebola.  The Ebola Biobank Governance Group (EBGG) was established to guarantee equality of access to the biobank for the most scientifically valuable research including by researchers from low and middle-income countries. Ensuring benefit to the people of Sierra Leone is an over-arching principle for decisions of the EBGG.  Four ongoing research collaborations are based on the first wave of biobank proposals approved by EBGG.  Whilst the biobank is a valuable resource its completeness and sample quality are consistent with the outbreak conditions under which they were collected

Prevalence of drug resistance mutations among ART-naive and -experienced HIV-infected patients in Sierra Leone

Objectives: The aim of this study was to assess the prevalence of HIV drug resistance (HIVDR) in HIV-infected ART-naive and -experienced patients in Sierra Leone. Patients and methods: We conducted a cross-sectional study of HIV-positive adults aged 18 years at Connaught Hospital in Freetown, Sierra Leone in November 2017. Sequencing was performed in the reverse transcriptase, protease and integrase regions, and interpreted using the Stanford HIVDR database andWHO 2009mutation list. Results: Two hundred and fifteen HIV-infected patients were included (64 ART naive and 151 ART experienced). The majority (66%) were female, the median age was 36 years and the median ART exposure was 48months. The majority (83%) were infected with HIV-1 subtype CRF02_AG. In the ART-naive group, the pretreatment drug resistance (PDR) prevalence was 36.7% (14.2% to NRTIs and 22.4% to NNRTIs). The most prevalent PDR mutations were K103N (14.3%), M184V (8.2%) and Y181C (4.1%). In the ART-experienced group, 64.4% harboured resistance-associated mutations (RAMs) and the overall prevalence of RAMs to NRTIs and NNRTIs was 85.2% (52/61) and 96.7% (59/61), respectively. The most prevalent RAMs were K103N (40.7%), M184V (28.8%), D67N (15.3%) and T215I/F/Y (15.3%). Based on the genotypic susceptibility score estimates, 22.4% of ART-naive patients and 56% of ART-experienced patients were not susceptible to first-line ART used in Sierra Leone. Conclusions: A high prevalence of circulating NRTI- and NNRTI-resistant variants was observed in ART-naive and -experienced HIV-1-infected patients in Sierra Leone. This necessitates the implementation of HIVDR surveillance programmes to inform national ART guidelines for the treatment and monitoring of HIV-infected patients in Sierra Leone.Xunta Galicia-Fondo Social Europeo | Ref. IN606A-2016/023Case Western Reserve University | Ref. NIH NIAID T32 AI07024Instituto de Salud Carlos III and Fondo Europeo de Desarrollo Regional-FEDER | Ref. RD16/0025/002

Lassa Virus Circulation in Small Mammal Populations in Bo District, Sierra Leone.

Lassa fever is a viral hemorrhagic fever caused by the Lassa virus LASV, which was first isolated in the rodent Mastomys natalensis in 1974 in Kenema, Sierra Leone. As little is known about the abundance and the presence of LASV in rodents living in the Bo area, we carried out a small mammal longitudinal population survey. A standardized trapping session was performed in various habitats and seasons in six villages over two years (2014-2016) and samples collected were tested for arenavirus IgG and LASV. A Bayesian phylogenetic analysis was performed on sequences identified by PCR. A total of 1490 small mammals were collected, and 16 rodent species were identified, with M. natalensis (355, 24%) found to be the most prevalent species. Forty-one (2.8%) samples were IgG positive, and 31 of these were trapped in homes and 10 in surrounding vegetation. Twenty-nine of 41 seropositive rodents were M. natalensis. We detected four LASV by PCR in two villages, all found in M. natalensis. Phylogenetic analysis showed that the sequences were distributed within the Sierra Leonean clade within lineage IV, distinguishing a Bo sub-clade older than a Kenema sub-clade. Compared to other settings, we found a low abundance of M. natalensis and a low circulation of LASV in rodents in villages around Bo district