Cordylobia anthropophaga (Diptera: Calliphoridae) outside Africa: a case of furuncular myiasis in a child returning from Congo

International travel to tropical countries accounts for an increasing incidence of imported diseases. An unusual case of furuncular myiasis due to Cordylobia anthropophaga (Blanchard) is reported in northern France in a 9-mo-old infant, after a 4-mo stay in Congo. A review has been made of the major cases of imported furuncular myiasis due to Cordylobia, as well as identification of second larval instars and management of the myiasis.     

Mechanical strength of repairs of the hip piriformis tendon

Mechanical properties of repairs of the piriformis tendon to the proximal femur were examined in a cadaveric model. Four constructs were separately tested: a suture anchor in the proximal femur, the anchor to suture interface, the suture in tendon interface, and a bone bridge style repair. The weakest interface was the anchor in the bone in cases in which the bone quality was poor. In specimens with high bone quality, the weakest interface was the suture in the anchor. A positive correlation was seen between Singh score for each femur and failure load of the anchor-bone constructs. Therefore, repairing the short external rotators after procedures involving a posterior approach to the hip may be warranted in patients with good bone quality.     

Novel multiplexed HIV/simian immunodeficiency virus antibody detection assay

Like most emerging infectious disease viruses, HIV is also of zoonotic origin. To assess the risk for cross-species transmission of simian immunodeficiency viruses (SIVs) from nonhuman primates to humans in the Democratic Republic of Congo, we collected 330 samples derived from nonhuman primate bushmeat at 3 remote forest sites. SIV prevalences were estimated by using a novel high-throughput assay that included 34 HIV and SIV antigens in a single well. Overall, 19% of nonhuman primate bushmeat was infected with SIVs, and new SIV lineages were identified. Highest SIV prevalences were seen in red-tailed guenons (25%) and Tshuapa red colobus monkeys (24%), representing the most common hunted primate species, thus increasing the likelihood for cross-species transmission. Additional studies are needed to determine whether other SIVs crossed the species barrier. With the newly developed assay, large-scale screening against many antigens is now easier and faster.     

A Phylogeographic Investigation of African Monkeypox

Monkeypox is a zoonotic disease caused by a virus member of the genus Orthopoxvirus and is endemic to Central and Western African countries. Previous work has identified two geographically disjuct clades of monkeypox virus based on the analysis of a few genomes coupled with epidemiological and clinical analyses; however, environmental and geographic causes of this differentiation have not been explored. Here, we expand previous phylogenetic studies by analyzing a larger set of monkeypox virus genomes originating throughout Sub-Saharan Africa to identify possible biogeographic barriers associated with genetic differentiation; and projected ecological niche models onto environmental conditions at three periods in the past to explore the potential role of climate oscillations in the evolution of the two primary clades. Analyses supported the separation of the Congo Basin and West Africa clades; the Congo Basin clade shows much shorter branches, which likely indicate a more recent diversification of isolates within this clade. The area between the Sanaga and Cross Rivers divides the two clades and the Dahomey Gap seems to have also served as a barrier within the West African clade. Contraction of areas with suitable environments for monkeypox virus during the Last Glacial Maximum, suggests that the Congo Basin clade of monkeypox virus experienced a severe bottleneck and has since expanded its geographic range.     

Immunogenicity of rVSVΔG-ZEBOV-GP Ebola vaccination in exposed and potentially exposed persons in the Democratic Republic of the Congo

Despite more than 300,000 rVSVΔG-ZEBOV-glycoprotein (GP) vaccine doses having been administered during Ebola virus disease (EVD) outbreaks in the Democratic Republic of the Congo (DRC) between 2018 and 2020, seroepidemiologic studies of vaccinated Congolese populations are lacking. This study examines the antibody response at 21 d and 6 mo postvaccination after single-dose rVSVΔG-ZEBOV-GP vaccination among EVD-exposed and potentially exposed populations in the DRC. We conducted a longitudinal cohort study of 608 rVSVΔG-ZEBOV-GP–vaccinated individuals during an EVD outbreak in North Kivu Province, DRC. Participants provided questionnaires and blood samples at three study visits (day 0, visit 1; day 21, visit 2; and month 6, visit 3). Anti-GP immunoglobulin G (IgG) antibody titers were measured in serum by the Filovirus Animal Nonclinical Group anti-Ebola virus GP IgG enzyme-linked immunosorbent assay. Antibody response was defined as an antibody titer that had increased fourfold from visit 1 to visit 2 and was above four times the lower limit of quantification at visit 2; antibody persistence was defined as a similar increase from visit 1 to visit 3. We then examined demographics for associations with follow-up antibody titers using generalized linear mixed models. A majority of the sample, 87.2%, had an antibody response at visit 2, and 95.6% demonstrated antibody persistence at visit 3. Being female and of young age was predictive of a higher antibody titer postvaccination. Antibody response and persistence after Ebola vaccination was robust in this cohort, confirming findings from outside of the DRC.

Since the rVSVΔG-ZEBOV-glycoprotein (GP) vaccine completed clinical trials in West Africa, over 300,000 doses of the vaccine have been deployed in response to the multiple Ebola virus disease (EVD) outbreaks in the Democratic Republic of the Congo (DRC). While initially deployed under a “compassionate use/expanded access” protocol (1, 2), as of December 19, 2019, the vaccine was officially licensed by both the American (Food and Drug Administration, FDA) and European (European Medicines Agency) regulatory agencies (3, 4). Wide use of this vaccine was supported by evidence gathered in clinical trials and other studies, including those postlicensure conducted in North America and West Africa, which demonstrated short-term vaccine efficacy (5–16). In addition to short-term protection, clinical trials and other studies have provided evidence of Ebolavirus Zaire (EBOV)–specific antibody persistence up to 2 y postvaccination, suggesting that the vaccine may continue to offer protective immunity over time (5, 7, 8, 14, 15). While promising, observations of successful rVSVΔG-ZEBOV-GP vaccine performance in outbreak settings have mostly come from studies conducted at the end of the 2014 to 2016 West African EVD outbreak (7, 13, 14, 17). Such studies in the DRC are lacking.Furthermore, recent evidence of breakthrough infections within the DRC has highlighted the need for DRC-specific vaccine research, including magnitude and durability of serological response after rVSVΔG-ZEBOV-GP vaccination in Congolese populations. In April 2019, the World Health Organization (WHO) released a preliminary report of rVSVΔG-ZEBOV-GP efficacy in the 2018 to 2020 Beni outbreak. Among 93,965 people at risk who were vaccinated, there were 15 confirmed EVD cases with onset of symptoms 10 d or more postvaccination (18). Another report describes an individual who presented with EVD 6 mo after vaccination, initiating a chain of transmission resulting in 91 subsequent infections (19), prompting questions around the duration of protection. These recent events highlight both the consequences of breakthrough infections and the possibility of waning immunity postvaccination.When considering rVSVΔG-ZEBOV-GP performance in the DRC, there are several factors that may impact the effect of vaccination in Congolese populations. First, an increase in vaccination dose could have resulted in increased immunogenicity in the DRC. Vaccination deployment during the EVD outbreak of 2018 initially included double the plaque-forming units (PFUs) in the vaccine dosage compared to what was used in West Africa (20 million PFU/mL versus 10 million PFU/mL, respectively) (20). As previous studies have identified varying immunogenicity after different vaccine doses in different locations, this variation in vaccine dose could lead to differing antibody responses from previously studied cohorts (15). Second, an important component of the vaccine deployment was the requirement for an ultracold chain (storage of vaccine at −70 °C), which poses extreme logistical challenges in resource-constrained environments. Despite considerable efforts to avoid cold chain failures, it is plausible that fluctuations could have occurred and caused changes in vaccine effectiveness (21). Third, populations in this region may have a baseline level of filovirus seroreactivity that may enable a more robust response to Ebola vaccination (15, 22). Previous serologic studies in the DRC have indicated that Congolese populations may not be naive to filovirus exposures, with individuals presenting evidence of robust antibody responses to various filoviruses in the absence of a known history of EVD (23–26). While there had never been a reported EVD outbreak in North Kivu prior to 2018, this province is known for highly mobile populations; proximity to large forested areas, which may harbor filovirus or filovirus-like pathogens; and access to cross-border populations, including those from Uganda, which have had previous filovirus outbreaks (27–29). Finally, the underlying prevalence of immunosuppressive conditions, such as HIV infection and poor nutritional status, could hinder vaccine immunogenicity in Congolese populations (30).Given the DRC’s unique landscape, which includes evidence of breakthrough infections, a more thorough region-specific understanding of serologic response to Ebola vaccination is needed. Various factors such as vaccine dose, storage conditions, current infections, and previous exposure may alter the magnitude and durability of antibody response after vaccination in Congolese populations (7, 31, 32). To better understand rVSVΔG-ZEBOV-GP performance in the DRC, we conducted a seroepidemiologic study of postvaccination antibody persistence in Congolese populations, who may have meaningfully different experiences than those in West Africa. Here, we provide a preliminary report of antibody response and persistence, along with potential predictors, after single-dose rVSVΔG-ZEBOV-GP vaccination among EVD-exposed and potentially exposed populations in the DRC.     

Effect of the electron donating group on the excited-state electronic nature and epsilon-near-zero properties of curcuminoid-borondifluoride dyes

Epsilon-near-zero (ENZ) properties have been reported in organic molecular films. In particular, cyanine and squaraine films have been shown to exhibit ENZ properties in the visible spectral region with a strong 3^rd order nonlinear optical response near the ENZ spectral region. Noting both cyanine and squaraine belong to the polymethine family, a series of six curcuminoid borondifluoride (Curc) derivatives were developed to examine whether such a polymethine character is positively correlated with the ENZ property of the organic films. Those Curc derivatives possess a Donor–Acceptor–Donor (D–A–D) architecture with acceptor, AcacBF₂, located at the molecular center. The backbone of Curc is designed such that the donor strength can be tuned to transit between charge transfer (CT) and polymethine character. This balance between CT and polymethine character of the Curc series is examined based on the Lippert–Mataga plot. As donor strength in the D–A–D structure increases, CT character is less marked resulting in a more dominant polymethine character. The structural and optical properties of the Curc films with a thickness in the order of 30 nm were examined to correlate the polymethine character with the ENZ response. The results obtained in isotropic Curc thin films demonstrate that an increase of polymethine character associated with a stronger donor strength leads to an appearance/enhancement of the ENZ property in the visible spectrum range from 500 to 670 nm. Overall, this study provides useful guidelines to engineer new organic materials showing ENZ properties in a desired spectral range.

Epsilon-near-zero (ENZ) properties have been reported in organic molecular films.     

Economic benefits of keeping vaccines at ambient temperature during mass vaccination: the case of meningitis?A vaccine in Chad

Objective

To evaluate the potential economic benefits of keeping a meningitis A vaccine at or near ambient temperature for up to 4 days during a mass vaccination campaign.

Methods

During a 10-day mass vaccination campaign against meningitis A in three regions of Chad in 2011, the costs associated with storage and transport of the vaccine in a traditional cold chain system were evaluated. A mathematical model was used to estimate the savings that could have been achieved if the vaccine had been stored at or near ambient temperature – in a “controlled temperature” chain – at the peripheral levels of the supply chain system.

Findings

The cost of the cold chain and associated logistics used in the campaign in Chad was 0.24 United States dollars (US$) per person vaccinated. In the modelled scenario for a controlled temperature chain, however, these costs dropped by 50% and were estimated to be only US$ 0.12 per person vaccinated.

Conclusion

The implementation of a “controlled temperature” chain at the most peripheral levels of the supply chain system – assuming no associated loss of vaccine potency, efficacy or safety – could result in major economic benefits and allow vaccine coverage to be extended in low-resource settings.