Novel Tools for Lassa Virus Surveillance in Peri-domestic Rodents

Background

Lassa fever (LF) is a rodent-borne disease endemic to West Africa. In the absence of licensed therapeutics or vaccines, rodent exclusion from living spaces remains the primary method of preventing LF. Zoonotic surveillance of Lassa virus (LASV), the etiologic agent of LF, can assess the burden of LASV in a region and guide public health measures against LF.

Methods

In this study, we adapted commercially available LASV human diagnostics to assess the prevalence of LASV in peri-domestic rodents in Eastern Sierra Leone. Small mammal trapping was conducted in Kenema district, Sierra Leone between November 2018-July 2019. LASV antigen was detected using a commercially available LASV NP antigen rapid diagnostic test. LASV IgG antibodies against LASV nucleoprotein (NP) and glycoprotein (GP) were tested by adapting a commercially available semi-quantitative enzyme linked immunosorbent assay (ELISA) for detection of mouse-related and rat-related species IgG.

Findings

Of the 373 tested specimens, 74 (20%) tested positive for LASV antigen. 40 (11%) specimens tested positive for LASV NP IgG, while an additional 12 (3%) specimens only tested positive for LASV GP IgG. Simultaneous antigen presence and IgG antibody presence was linked in Mastomys sp. specimens (p < 0.01), but not Rattus sp. specimens (p = 1). Despite the link between antigen presence and IgG antibody presence in Mastomys sp., the strength of antigen response did not correlate with the strength of IgG response to either GP IgG or NP IgG.

Interpretation

The tools developed in this study can aid in the generation of valuable public health data for rapid field assessment of LASV burden during outbreak investigations and general LASV surveillance.

Funding

Funding for this work was supported by the National Institute of Allergy and Infectious Diseases National Institute of Health, Department of Health and Human Services under the following grants: International Collaboration in Infectious Disease Research on Lassa fever and Ebola - ICIDR - U19 AI115589, Consortium for Viral Systems Biology - CViSB - 5U19AI135995, West African Emerging Infectious Disease Research Center - WARN-ID - U01AI151812, West African Center for Emerging Infectious Diseases: U01AI151801.

Exposure modality influences viral kinetics but not respiratory outcome of COVID-19 in multiple nonhuman primate species

The novel coronavirus SARS-CoV-2 emerged in late 2019, rapidly reached pandemic status, and has maintained global ubiquity through the emergence of variants of concern. Efforts to develop animal models have mostly fallen short of recapitulating severe disease, diminishing their utility for research focusing on severe disease pathogenesis and life-saving medical countermeasures. We tested whether route of experimental infection substantially changes COVID-19 disease characteristics in two species of nonhuman primates (Macaca mulatta; rhesus macaques; RM, Chlorocebus atheiops; African green monkeys; AGM). Species-specific cohorts were experimentally infected with SARS-CoV-2 by either direct mucosal (intratracheal + intranasal) instillation or small particle aerosol in route-discrete subcohorts. Both species demonstrated analogous viral loads in all compartments by either exposure route although the magnitude and duration of viral loading was marginally greater in AGMs than RMs. Clinical onset was nearly immediate (+1dpi) in the mucosal exposure cohort whereas clinical signs and cytokine responses in aerosol exposure animals began +7dpi. Pathologies conserved in both species and both exposure modalities include pulmonary myeloid cell influx, development of pleuritis, and extended lack of regenerative capacity in the pulmonary compartment. Demonstration of conserved pulmonary pathology regardless of species and exposure route expands our understanding of how SARS-CoV-2 infection may lead to ARDS and/or functional lung damage and demonstrates the near clinical response of the nonhuman primate model for anti-fibrotic therapeutic evaluation studies.

Cross-Reactive Antibodies to SARS-CoV-2 and MERS-CoV in Pre-COVID-19 Blood Samples from Sierra Leoneans

Many countries in sub-Saharan Africa have experienced lower COVID-19 caseloads and fewer deaths than countries in other regions worldwide. Under-reporting of cases and a younger population could partly account for these differences, but pre-existing immunity to coronaviruses is another potential factor. Blood samples from Sierra Leonean Lassa fever and Ebola survivors and their contacts collected before the first reported COVID-19 cases were assessed using enzyme-linked immunosorbent assays for the presence of antibodies binding to proteins of coronaviruses that infect humans. Results were compared to COVID-19 subjects and healthy blood donors from the United States. Prior to the pandemic, Sierra Leoneans had more frequent exposures than Americans to coronaviruses with epitopes that cross-react with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), SARS-CoV, and Middle Eastern respiratory syndrome coronavirus (MERS-CoV). The percentage of Sierra Leoneans with antibodies reacting to seasonal coronaviruses was also higher than for American blood donors. Serological responses to coronaviruses by Sierra Leoneans did not differ by age or sex. Approximately a quarter of Sierra Leonian pre-pandemic blood samples had neutralizing antibodies against SARS-CoV-2 pseudovirus, while about a third neutralized MERS-CoV pseudovirus. Prior exposures to coronaviruses that induce cross-protective immunity may contribute to reduced COVID-19 cases and deaths in Sierra Leone.

Space-Time Trends in Lassa Fever in Sierra Leone by ELISA Serostatus, 2012-2019

Lassa fever (LF) is a viral hemorrhagic disease found in Sub-Saharan Africa and is responsible for up to 300,000 cases and 5000 deaths annually. LF is highly endemic in Sierra Leone, particularly in its Eastern Province. Kenema Government Hospital (KGH) maintains one of only a few LF isolation facilities in the world with year-round diagnostic testing. Here we focus on space-time trends for LF occurring in Sierra Leone between 2012 and 2019 to provide a current account of LF in the wake of the 2014–2016 Ebola epidemic. Data were analyzed for 3277 suspected LF cases and classified as acute, recent, and non-LF or prior LF exposure using enzyme-linked immunosorbent assays (ELISAs). Presentation rates for acute, recent, and non-LF or prior LF exposure were 6.0% (195/3277), 25.6% (838/3277), and 68.4% (2244/3277), respectively. Among 2051 non-LF or prior LF exposures, 33.2% (682/2051) tested positive for convalescent LF exposure. The overall LF case-fatality rate (CFR) was 78.5% (106/135). Both clinical presentations and confirmed LF cases declined following the Ebola epidemic. These declines coincided with an increased duration between illness onset and clinical presentation, perhaps suggesting more severe disease or presentation at later stages of illness. Acute LF cases and their corresponding CFRs peaked during the dry season (November to April). Subjects with recent (but not acute) LF exposure were more likely to present during the rainy season (May to October) than the dry season (p < 0.001). The findings here suggest that LF remains endemic in Sierra Leone and that caseloads are likely to resume at levels observed prior to the Ebola epidemic. The results provide insight on the current epidemiological profile of LF in Sierra Leone to facilitate LF vaccine studies and accentuate the need for LF cohort studies and continued advancements in LF diagnostics.

Field evaluation of a Pan-Lassa rapid diagnostic test during the 2018 Nigerian Lassa fever outbreak

Lassa virus (LASV) is the causative agent of Lassa fever (LF), an often-fatal hemorrhagic disease. LF is endemic in Nigeria, Sierra Leone and other West African countries. Diagnosis of LASV infection is challenged by the genetic diversity of the virus, which is greatest in Nigeria. The ReLASV Pan-Lassa Antigen Rapid Test (Pan-Lassa RDT) is a point-of-care, in vitro diagnostic test that utilizes a mixture of polyclonal antibodies raised against recombinant nucleoproteins of representative strains from the three most prevalent LASV lineages (II, III and IV). We compared the performance of the Pan-LASV RDT to available quantitative PCR (qPCR) assays during the 2018 LF outbreak in Nigeria. For patients with acute LF (RDT positive, IgG/IgM negative) during initial screening, RDT performance was 83.3% sensitivity and 92.8% specificity when compared to composite results of two qPCR assays. 100% of samples that gave Ct values below 22 on both qPCR assays were positive on the Pan-Lassa RDT. There were significantly elevated case fatality rates and elevated liver transaminase levels in subjects whose samples were RDT positive compared to RDT negative.

Effect of testing temperature on internal egg quality measurements

The objective of this study was to determine the effect of egg testing temperature on quality measurements of shell eggs. The quality measurements compared included 3 Haugh unit (HU) devices (electronic Haugh, tripod Haugh, and Haugh meter), egg weight, albumen height, albumen width, albumen index, yolk width, yolk height, yolk index, percentage of thin albumen, and vitelline membrane strength at 3 temperatures of 5, 13, and 23 degrees C from 2 strains of laying hens (Hyline W36 and Bovans White) at 2 storage times. The HU measurements averaged 72.44 at time zero and 59.99 at 7 wk. At 7 wk for all devices, HU values decreased 6 units with increased temperature (P < 0.05). The electronic Haugh and tripod Haugh devices gave equal measurements for all testing conditions. The Haugh meter gave equal values at 5 degrees C for fresh eggs but lower HU at higher temperatures and 7 wk storage. Thus, it is recommended that egg testing temperature be reported when HU are measured. Coefficient of variation generally increased for all HU methods with increasing temperature. Although there was a proportionately different amount of thin albumen detected between the strains of laying hens, no significant difference was seen in HU. From the evaluated methods for measuring quality, the electronic Haugh, which electronically measures albumen height and calculates HU, provided the lowest coefficient of variation, was sensitive to quality loss, and gave the highest quality measurement (5 degrees C).

A comparison of 1% prilocaine with 0.5% ropivacaine for outpatient-based surgery under axillary brachial plexus block

We compared the use of 1% prilocaine with 0.5% ropivacaine for axillary brachial plexus anesthesia in a double-blinded manner in day-stay patients to determine the better of the two local anesthetics in terms of onset time and duration of motor block. Sixty patients scheduled for outpatient upper-limb surgery were allocated randomly to receive either prilocaine (28 patients) or ropivacaine (32 patients) at a volume of 0.7 mL/kg. The brachial plexus was located with a plexus needle and nerve stimulator. By 20 min after injection of prilocaine or ropivacaine, there was no difference in analgesic effect. By this time, it was apparent whether or not a block was going to be adequate for surgery. Pain returned after a mean of 278 min (SD 111 min; range, 160-630 min) with prilocaine as compared with 636 min (SD 284 min; range, 210-1440 min) with ropivacaine. Analgesia use was similar in both groups. Duration of motor block with prilocaine was a mean of 254 min (SD 62 min; range, 130-385 min), as compared with 642 min (SD 199 min; range, 350-1080 min) with ropivacaine. We conclude that there is no clinically important difference between 1% prilocaine and 0.5% ropivacaine in time to onset of axillary brachial plexus block when they are injected in equal volumes. There is a significantly longer duration of action with ropivacaine, which may make it less suitable for day-stay upper-limb surgery because of the handicap from reduced muscle power.

IMPLICATIONS

This study compares two local anesthetics to determine which is most suitable for day-stay upper-limb surgery under axillary brachial plexus block. Prilocaine 1% is more suitable than ropivacaine 0.5% because of a more prolonged duration of action of ropivacaine, although this could be useful in other circumstances.

A comparison of informed consent for obstetric anaesthesia in the USA and the UK

The practice of 75 UK and 75 US obstetric anaesthetists in obtaining informed consent for obstetric anaesthesia (for caesarean section) and obstetric analgesia (for labour) was compared using a postal questionnaire. The response rate was approximately 60% for each group. Of the US anaesthetists 47% obtained separate written consent for obstetric anaesthesia compared to 22% of the UK group (P=0.012). Corresponding percentages for epidural analgesia were 52% for the US, and 15% for the UK (P < 0.001). Significantly more of the listed risks and benefits relating to general anaesthesia were discussed by the US anaesthetists compared to the UK group, median (interquartile range), 6 (4-7) and 3 (1-4), P < 0.001. There was no significant difference in discussion before regional anaesthesia but the US group discussed more information before epidural analgesia for labouring mothers obtunded by pain or drugs. These results suggest that discussion and documentation of informed consent for obstetric anaesthesia and analgesia could be improved in both countries, especially the UK.

Cervical carcinoma in women less than 35 years of age

We retrospectively studied 80 patients, less than 35 years old, who were being treated for invasive cervical carcinoma at Charity Hospital of Louisiana in New Orleans. The period covered by the study was March 1980 to November 1989. The study group represented 9.3% (80/862) of the total patients seen with the disease. Disease stage was IB in 50 patients, IIA in 4, IIB in 14, IIIA in 5, IIIB in 6, and IVA in 1 patient. Histopathologic classes included 74 squamous cell carcinomas, 3 adenosquamous carcinomas, 2 adenocarcinomas, and 1 anaplastic carcinoma. Treatment used was either radical hysterectomy, irradiation alone, or irradiation followed by hysterectomy. Five-year actuarial survival rates were as follows: stage IB, 81.6%; stage IIA, 25.0%; stage IIB, 29.8%; stage IIIA, 20.0%; and stage IIIB, 33.4%. The only patient with stage IV cancer died of disease. Our findings do not reveal a relationship between age and survival in stage IB carcinoma of the cervix, and the numbers in the other stages are too small to comment on.

Feline serum antibody responses to Toxoplasma gondii and characterization of target antigens

The Toxoplasma gondii-specific target antigens for feline immunoglobulin M (IgM) and immunoglobulin G (IgG) immune responses were studied longitudinally using western blot immunoassay in 8 cats experimentally inoculated with T. gondii strain ME49. Multiple antigens were recognized by IgM and IgG during the course of infection. Dense bands were associated with 12 antigens in the IgM western blot immunoassay and 30 antigens in the IgG western blot immunoassay. Immunoglobulin M responses were maximal on week 4 postinoculation (PI) and were greatly diminished by week 20 PI. Immunoglobulin G responses were maximal on week 12 PI. On week 20 PI, the 19-kDa (6/8 samples), 26-kDa (8/8 samples), 28-kDa (8/8 samples), 31-kDa (7/8 samples), 35-kDa (6/8 samples), 51-kDa (6/8 samples), 55-kDa (7/8 samples), and 65-kDa (7/8 samples) antigens were recognized most commonly in the IgG western blot immunoassay. When the western blot immunoassay results were compared to enzyme-linked immunosorbent assay (ELISA) results, there was no clear advantage to the development of IgM-ELISA, IgG-ELISA, IgM western blot immunoassay, or IgG western blot immunoassay using a single antigen instead of multiple antigens as the detection system for the diagnosis of recent infection.

Diclofenac for analgesia after caesarean section

The analgesic efficacy of a single intramuscular dose of 75 mg diclofenac given after elective Caesarean section was studied in 50 women in a double-blind randomised manner using a patient-controlled analgesia system. The mean 18 h papavaretum consumption of the placebo group was significantly greater (91.4 mg compared to 61.4 mg). Subjective experience of pain and observed sedation were significantly greater in the control group up to 6 h after operation.

Appraising current therapy for breast cancer. 2. Irradiation

The best combination of methods for managing primary breast cancer may not yet be known. Radiation therapy has been proved effective in decreasing the incidence of local and regional recurrence following mastectomy. Thus, until a superior regimen is established, I recommend local and regional irradiation for patients at high risk for recurrence. Local irradiation is also an effective means of achieving palliation of symptoms associated with metastatic disease.

Microtubules: evidence for 13 protofilaments

When microtubules are fixed in glutaraldehyde in the presence of tannic acid and thin sections cut, the subunit structure of the microtubule is readily observed without the need of image reinforcement. Seven types of microtubules were analyzed: those in the heliozoan axoneme, the mitotic apparatus, the contractile axostyle, repolymerized microtubules derived from the chick brain, the central pair in flagella, and the A tubules of flagella and the basal body. In all cases microtubules were composed of 13 equally spaced protofilaments. The B tubules in flagella and the basal body appear to be composed of 11 subunits. The connections of the B to the A and the C to the B are described. A model of a microtubule is presented.