112 research outputs found
Odyssean malaria outbreaks in Gauteng Province, South Africa, 2007 - 2013
Background. Odyssean malaria refers to malaria transmitted by translocated mosquitoes and is a diagnosis of exclusion, as the probability of finding the responsible vector is miniscule. We believe that road traffic from endemic areas in and around South Africa is the source of most of the infected mosquitoes. Because of the unexpected nature of the disease, diagnosis is often delayed and severe and complicated malaria is common.Objectives. To describe outbreaks of odyssean malaria during the period 2007 through 2013 in Gauteng Province, South Africa, and to educate healthcare workers about this form of malaria.Methods. Site visits, environmental hygiene inspections, patient interviews, and entomological investigations for adult mosquitoes and larvae in potential breeding sites were done in each identified outbreak.Results. Over the period, 14 laboratory-proven and 7 probable cases of odyssean malaria were investigated. There were 2 deaths (9.5% case fatality rate, approximately 10 times higher than the national fatality rate for malaria). We describe two recent clusters of cases in detail, and emphasise the importance of clinician awareness of this rare but frequently severe form of malaria.Conclusion. Odyssean malaria cases are inevitable in South Africa, given the volume of road, rail and air traffic from malaria risk areas into Gauteng and other non-endemic provinces. It is likely that many cases are missed, owing to the rare and sporadic nature of the condition. Malaria should always be kept in mind as a cause of unexplained fever and thrombocytopenia, even in the absence of a travel history.
Diagnostic testing practices for diarrhoeal cases in South African public hospitals
BACKGROUND : Stool samples submitted for diagnostic testing represent a proportion of diarrhoeal cases seeking
healthcare, and an even smaller proportion of diarrhoeal cases in the community. Despite this, surveillance relies
heavily on these laboratory results. This study described diarrhoeal diagnostic practices and aetiological agents of
diarrhoea in patients admitted to three South African public hospitals in order to understand biases in surveillance
data, and inform guidelines, diagnostic and laboratory practices to improve clinical management.
METHODS : A doctors’ survey was conducted to determine sample submission, diarrhoeal treatment and barriers to
submitting samples for testing. Results for all samples submitted for routine diagnostics were obtained from the NHLS
Central Data Warehouse. An enhanced surveillance study enrolled patients with acute diarrhoea at the same hospitals
over the same period. Differences between routine culture results and molecular testing from the surveillance study
were described.
RESULTS : Stool samples were seldom submitted for diagnostic testing (median of 10% of admitted cases). Current
diagnostic guidelines were not useful, hence most doctors (75.1%) relied on their own clinical judgement or judgement
of a senior clinician. Although most doctors (90.3%) agreed that diagnostics were helpful for clinical management,
they reported patients being unwilling to provide samples and long laboratory turnaround times. Routine
diagnostic data represent cases with chronic diarrhoea and dysentery since doctors are most likely to submit specimens
for these cases. Pathogen yield (number of pathogens detected for samples tested for specific pathogens)
was significantly higher in the surveillance study, which used molecular methods, than through routine diagnostic
services (73.3% versus 8.2%, p < 0.001), including for viruses (48.9% versus 2.6%, p < 0.001), bacteria (40.1% versus 2.2%,
p < 0.001) and parasites (16.2% versus 3.6%, p < 0.001). Despite viruses being commonly detected in the surveillance
study, viral testing was seldom requested in routine diagnostic investigations.
CONCLUSIONS : Comprehensive diagnostic and treatment guidelines are required for diarrhoeal diseases. These guidelines
should be informed by local epidemiological data, where diagnostic testing is reserved for cases most likely to
benefit from specific treatment. Optimisation of current diagnostic processes and methods are required for these
cases, specifically in terms of minimising turnaround times while maximising diagnostic acumen.The ANDEMIA study was supported by the German Federal Ministry of Education and Research.http://www.biomedcentral.com/bmcinfectdisam2023Medical VirologyPaediatrics and Child Healt
State-Level Policy Environments, Discrimination, and Victimization among Sexual and Gender Minority People
Legislation has been passed in some states to reduce discrimination and victimization toward sexual and gender minority people (SGM; people who are not solely heterosexual and/or whose gender identity is not equal to what is socially associated with sex assigned at birth). The purpose of these analyses is to test whether state-level policy environments are associated with past-year discrimination and victimization among SGM people. Cross-sectional data from The Population Research in Identity and Disparities for Equality (PRIDE) Study annual questionnaire (collected 2018–2019), a national study of the health of SGM adults in the USA, were used for these analyses. Measures included related to discrimination, victimization, and demographic characteristics. State-level policy environments were measured using data from the Movement Advancement Project. Logistic regression analyses evaluated state-level policy environment scores and past-year discrimination and victimization among gender identity categories. In this sample, 7044 people (gender minority n = 2530) were included. Cisgender sexual minority (odds ratio [OR] = 1.007, p = 0.041) and the gender expansive subgroup of gender minority people (OR = 1.010, p = 0.047) in states with more protective policy environments had greater odds of discrimination. The gender expansive subgroup was found to have greater odds of victimization in states with more protective policy environments (OR = 1.003, p \u3c 0.05). There was no relationship between state-level policy environments and victimization among any other study groups. SGM people may experience increased risk for discrimination and victimization despite legislative protections, posing continued risks for poor health outcomes and marginalization. Evaluation of factors (e.g., implementation strategies, systems of accountability) that influence the effectiveness of state-level polices on the reported experiences of discrimination and victimization among SGM people is needed
Identifying gaps in hand hygiene practice to support tailored target audience messaging in Soweto : a cross-sectional community survey
Effective risk communication is essential for outbreak mitigation, as recently highlighted
during the coronavirus disease 2019 (COVID-19) pandemic. Hand hygiene is one of the
proposed public health interventions to protect against severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2) acquisition and transmission along with social distancing,
improved ventilation, environmental cleaning, and wearing of masks. Improving hand
hygiene practices in the community requires an understanding of the socio-behavioural
context. This cross-sectional community survey in Soweto identified gaps in hand hygiene,
which can inform appropriate messaging at the community level. Only 42% of survey
respondents practiced adequate hand hygiene. Tailored educational messaging should be
targeted at young adults in particular, and the importance of soap for hand hygiene must be
emphasised for all age groups. Risk communication should expand to focus on preventing
multiple infectious diseases during and beyond the COVID-19 pandemic.GlaxoSmithKline and the German Federal Ministry of Education and Research. The CHAMPS programme is funded by the Bill & Melinda Gates Foundation.https://sajid.co.za/index.php/sajiddm2022Medical Virolog
Diarrhoeal diseases in Soweto, South Africa, 2020 : a cross-sectional community survey
BACKGROUND : In South Africa, there are limited data on the burden of diarrhoea at a community level, specifically in
older children and adults. This community survey estimated rates of and factors associated with diarrhoea across all
ages and determined the proportion of cases presenting to healthcare facilities.
METHODS : Households were enrolled from an existing urban health and demographic surveillance site. A household
representative was interviewed to determine associated factors and occurrence of diarrhoea in the household, for
all household members, in the past 2 weeks (including symptoms and health seeking behaviour). Diarrhoeal rate of
any severity was calculated for 15 years age groups. Factors associated with diarrhoea
and health seeking behaviour were investigated using binomial logistic regression.
RESULTS : Diarrhoeal rate among respondents (2.5 episodes/person-year (95% CI, 1.8–3.5)) was significantly higher
than for other household members (1.0 episodes/person-year (95% CI, 0.8–1.4); IRR = 2.4 (95% CI, 1.5–3.7) p < 0.001).
Diarrhoeal rates were similar between age groups, however younger children (< 5 years) were more likely to
present to healthcare facilities than adults (OR = 5.9 (95% CI, 1.1–31.4), p = 0.039). Oral rehydration solution was used
in 44.8% of cases. Having a child between 5 and 15 years in the household was associated with diarrhoea (OR = 2.3
(95% CI, 1.3–3.9), p = 0.003) and, while 26.4% of cases sought healthcare, only 4.6% were hospitalised and only 3.4%
of cases had a stool specimen collected. While the majority of cases were mild, 13.8% of cases felt they required
healthcare but were unable to access it.
CONCLUSION : Diarrhoeal rate was high across all age groups in this community; however, older children and adults
were less likely to present to healthcare, and are therefore underrepresented through facility-based clinical
surveillance. Current diarrhoeal surveillance represents a fraction of the overall cases occurring in the community.SUPPLEMENTARY MATERIAL: FIGURE S1. Health seeking for reported diarrhoeal episodes. TABLE S1. Factors associated with ORS knowledge.This work was supported by GlaxoSmithKline [E-Track 200238] and the
German Federal Ministry of Education and Research [grant number
81203616] to SLJ. The CHAMPS program is funded by the Bill & Melinda
Gates Foundation (Grant OPP1126780).http://www.biomedcentral.com/bmcpublichealtham2022Medical Virolog
Serum levels of inflammatory cytokines in Rift Valley fever patients are indicative of severe disease
BACKGROUND : Rift Valley fever (RVF) is a mosquito-borne viral zoonosis affecting domestic and wild ruminants,
camels and humans. Outbreaks of RVF are characterized by a sudden onset of abortions and high mortality
amongst domestic ruminants. Humans develop disease ranging from a mild flu-like illness to more severe
complications including hemorrhagic syndrome, ocular and neurological lesions and death. During the RVF
outbreak in South Africa in 2010/11, a total of 278 human cases were laboratory confirmed, including 25 deaths.
The role of the host inflammatory response to RVF pathogenesis is not completely understood.
METHODS : Virus load in serum from human fatal and non-fatal cases was determined by standard tissue culture
infective dose 50 (TCID50) titration on Vero cells. Patient serum concentration of chemokines and cytokines involved
in inflammatory responses (IL-8, RANTES, CXCL9, MCP-1, IP-10, IL-1β, IL-6, IL-10, TNF and IL-12p70) was determined
using cytometric bead assays and flow cytometry.
RESULTS : Fatal cases had a 1-log10 higher TCID50/ml serum concentration of RVF virus (RVFV) than survivors (p < 0.05).
There were no significant sequence differences between isolates recovered from fatal and non-fatal cases. Chemokines
and pro- and anti-inflammatory cytokines were detected at significantly increased (IL-8, CXCL9, MCP-1, IP-10, IL-10) or
decreased (RANTES) levels when comparing fatal cases to infected survivors and uninfected controls, or when
comparing combined infected patients to uninfected controls.
CONCLUSIONS : The results suggest that regulation of the host inflammatory responses plays an important role in the
outcome of RVFV infection in humans. Dysregulation of the inflammatory response contributes to a fatal outcome. The
cytokines and chemokines identified in this study that correlate with fatal outcomes warrant further investigation as
markers for disease severity.The Poliomyelitis Research Foundation (PRF),
grant number 12/10. PJvV is further supported by a grant from the Incentive
Funding for Rated Researchers program of the National Research Foundation
(NRF), South Africa.
This work is based on the research supported in part by the National
Research Foundation of South Africa (Grant specific unique reference
number UID 85544).http://www.virologyj.comam201
An outbreak of lymphocutaneous sporotrichosis among mine-workers in South Africa
BACKGROUND
The largest outbreak of sporotrichosis occurred between 1938 and 1947 in the gold mines
of Witwatersrand in South Africa. Here, we describe an outbreak of lymphocutaneous sporotrichosis
that was investigated in a South African gold mine in 2011.
METHODOLOGY
Employees working at a reopened section of the mine were recruited for a descriptive
cross-sectional study. Informed consent was sought for interview, clinical examination and
medical record review. Specimens were collected from participants with active or partiallyhealed
lymphocutaneous lesions. Environmental samples were collected from underground
mine levels. Sporothrix isolates were identified by sequencing of the internal transcribed
spacer region of the ribosomal gene and the nuclear calmodulin gene.
PRINCIPAL FINDINGS
Of 87 male miners, 81 (93%) were interviewed and examined, of whom 29 (36%) had skin
lesions; specimens were collected from 17 (59%). Sporotrichosis was laboratory-confirmed
among 10 patients and seven had clinically-compatible lesions. Of 42miners with known HIV
status, 11 (26%) were HIV-infected. No cases of disseminated disease were detected. Participants
with 3 years’ mining experience had a four times greater odds of developing sporotrichosis
than those who had been employed for >3 years (adjusted OR 4.0, 95%CI 1.2–13.1). Isolates from 8 patients were identified as Sporothrix schenckii sensu stricto by calmodulin
gene sequencing while environmental isolates were identified as Sporothrix mexicana.
CONCLUSIONS/SIGNIFICANCE
S. schenckii sensu stricto was identified as the causative pathogen. Although genetically
distinct species were isolated from clinical and environmental sources, it is likely that the source was contaminated soil and untreated wood underground. No cases occurred following
recommendations to close sections of the mine, treat timber and encourage consistent
use of personal protective equipment. Sporotrichosis is a potentially re-emerging disease
where traditional, rather than heavily mechanised, mining techniques are used. Surveillance
should be instituted at sentinel locations.http://www.plosntds.orgam201
Antibody stabilization for thermally accelerated deep immunostaining
Antibodies have diverse applications due to their high reaction specificities but are sensitive to denaturation when a higher working temperature is required. We have developed a simple, highly scalable and generalizable chemical approach for stabilizing off-the-shelf antibodies against thermal and chemical denaturation. We demonstrate that the stabilized antibodies (termed SPEARs) can withstand up to 4 weeks of continuous heating at 55 °C and harsh denaturants, and apply our method to 33 tested antibodies. SPEARs enable flexible applications of thermocycling and denaturants to dynamically modulate their binding kinetics, reaction equilibrium, macromolecular diffusivity and aggregation propensity. In particular, we show that SPEARs permit the use of a thermally facilitated three-dimensional immunolabeling strategy (termed ThICK staining), achieving whole mouse brain immunolabeling within 72 h, as well as nearly fourfold deeper penetration with threefold less antibodies in human brain tissue. With faster deep-tissue immunolabeling and broad compatibility with tissue processing and clearing methods without the need for any specialized equipment, we anticipate the wide applicability of ThICK staining with SPEARs for deep immunostaining
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TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution
The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a
satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A
ton-level liquid scintillator detector will be placed at about 30 m from a core
of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be
measured with sub-percent energy resolution, to provide a reference spectrum
for future reactor neutrino experiments, and to provide a benchmark measurement
to test nuclear databases. A spherical acrylic vessel containing 2.8 ton
gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon
Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full
coverage. The photoelectron yield is about 4500 per MeV, an order higher than
any existing large-scale liquid scintillator detectors. The detector operates
at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The
detector will measure about 2000 reactor antineutrinos per day, and is designed
to be well shielded from cosmogenic backgrounds and ambient radioactivities to
have about 10% background-to-signal ratio. The experiment is expected to start
operation in 2022
A point-of-care lateral flow assay for neutralising antibodies against SARS-CoV-2
Background: As vaccines against SARS-CoV-2 are now being rolled out, a better understanding of immunity to the virus, whether from infection, or passive or active immunisation, and the durability of this protection is required. This will benefit from the ability to measure antibody-based protection to SARS-CoV-2, ideally with rapid turnaround and without the need for laboratory-based testing.
Methods: We have developed a lateral flow POC test that can measure levels of RBD-ACE2 neutralising antibody (NAb) from whole blood, with a result that can be determined by eye or quantitatively on a small instrument. We compared our lateral flow test with the gold-standard microneutralisation assay, using samples from convalescent and vaccinated donors, as well as immunised macaques.
Findings: We show a high correlation between our lateral flow test with conventional neutralisation and that this test is applicable with animal samples. We also show that this assay is readily adaptable to test for protection to newly emerging SARS-CoV-2 variants, including the beta variant which revealed a marked reduction in NAb activity. Lastly, using a cohort of vaccinated humans, we demonstrate that our whole-blood test correlates closely with microneutralisation assay data (specificity 100% and sensitivity 96% at a microneutralisation cutoff of 1:40) and that fingerprick whole blood samples are sufficient for this test.
Interpretation: Taken together, the COVID-19 NAb-testTM device described here provides a rapid readout of NAb based protection to SARS-CoV-2 at the point of care
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