Evaluating the serological status of COVID-19 patients using an indirect immunofluorescent assay, France.

An indirect in-house immunofluorescent assay was developed in order to assess the serological status of COVID-19 patients in Marseille, France. Performance of IFA was compared to a commercial ELISA IgG kit. We tested 888 RT-qPCR-confirmed COVID-19 patients (1302 serum samples) and 350 controls including 200 sera collected before the pandemic, 64 sera known to be associated with nonspecific serological interference, 36 sera from non-coronavirus pneumonia and 50 sera from patient with other common coronavirus to elicit false-positive serology. Incorporating an inactivated clinical SARS-CoV-2 isolate as the antigen, the specificity of the assay was measured as 100% for IgA titre ≥ 1:200, 98.6% for IgM titre ≥ 1:200 and 96.3% for IgG titre ≥ 1:100 after testing a series of negative controls. IFA presented substantial agreement (86%) with ELISA EUROIMMUN SARS-CoV-2 IgG kit (Cohen's Kappa = 0.61). The presence of antibodies was then measured at 3% before a 5-day evolution up to 47% after more than 15 days of evolution. We observed that the rates of seropositivity as well as the titre of specific antibodies were both significantly higher in patients with a poor clinical outcome than in patients with a favourable evolution. These data, which have to be integrated into the ongoing understanding of the immunological phase of the infection, suggest that detection anti-SARS-CoV-2 antibodies is useful as a marker associated with COVID-19 severity. The IFA assay reported here is useful for monitoring SARS-CoV-2 exposure at the individual and population levels.

Retrospective overview of a COVID-19 outbreak in Mauritania.

A coronavirus disease 2019 (COVID-19) outbreak is currently ongoing in Mauritania. Until 1 July 2020, Mauritania health authorities reported 41 862 serologic and real-time reverse transcriptase PCR tests performed, of which 4472 (10.7%) were positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Male subjects were significantly more affected (57.1%) than female subjects (42.9%). Individuals of the age groups 15-34 years (35.8%) and 35-54 years (36.6%) were the most affected. There were 129 deaths (2.9%), 1677 recoveries (37.5%) and 2666 active cases (59.6%) of which 2261 (84.8%) were asymptomatic, 394 (14.7%) had mild symptoms and 11 (0.4%) had severe symptoms. A large proportion of fatalities (72%, 85/118) occurred among adults aged ≥55 years. Of 4472 positive cases, 4241 (94.8%) were infected through contact with a confirmed COVID-19 case, 133 (3.0%) had no contact with a confirmed COVID-19 case and 98 (2.2%) were imported. As a response to COVID-19, the Mauritanian authorities announced a set of preventive measures, including closure of land and air borders, night curfew, closure of markets, schools and universities and restriction of movement between cities. Control measures included the systematic testing of symptomatic patients, isolation and management of active cases, contact tracing and quarantine of people who have been in contact with a COVID-19-positive individual. We discuss the efforts of the Mauritanian government to combat this potentially life-threatening pneumonia.

Clinical efficacy of chloroquine derivatives in COVID-19 infection: comparative meta-analysis between the big data and the real world.

In the context of the current coronavirus disease 2019 (COVID-19) pandemic, we conducted a meta-analysis on the effects of chloroquine derivatives in patients, based on unpublished and published reports available publicly on the internet as of 27 May 2020. The keywords 'hydroxychloroquine', 'chloroquine', 'coronavirus', 'COVID-19' and 'SARS-Cov-2' were used in the PubMed, Google Scholar and Google search engines without any restrictions as to date or language. Twenty studies were identified involving 105 040 patients (19 270 treated patients) from nine countries (Brazil, China, France, Iran, Saudi Arabia, South Korea, Spain and the USA). Big data observational studies were associated with conflict of interest, lack of treatment dosage and duration, and absence of favourable outcome. Clinical studies were associated with favourable outcomes and details on therapy. Among clinical studies, three of four randomized controlled trials reported a significant favourable effect. Among clinical studies, a significant favourable summary effect was observed for duration of cough (OR 0.19, p 0.00003), duration of fever (OR 0.11, p 0.039), clinical cure (OR 0.21, p 0.0495), death (OR 0.32, p 4.1 × 10-6) and viral shedding (OR 0.43, p 0.031). A trend for a favourable effect was noted for the outcome 'death and/or intensive care unit transfer' (OR 0.29, p 0.069) with a point estimate remarkably similar to that observed for death (∼0.3). In conclusion, a meta-analysis of publicly available clinical reports demonstrates that chloroquine derivatives are effective to improve clinical and virological outcomes, but, more importantly, they reduce mortality by a factor of 3 in patients with COVID-19. Big data are lacking basic treatment definitions and are linked to conflict of interest. The retraction of the only big data study associated with a significantly deleterious effect the day after (June 5, 2020) the acceptance of the present work (June 4, 2020) confirms the relevance of this work.

Emergence of murine typhus in La Réunion, France, 2012-2017.

OBJECTIVE: Murine typhus (MT) is an acute zoonosis caused by Rickettsia typhi, a flea-borne rickettsiosis. The first autochthonous case was reported in 2012. Once autochthonous transmission of Rickettsia typhi was proven, we performed a prospective study to describe and raise awareness of this often-misdiagnosed disease among physicians. PATIENTS AND METHODS: We performed a prospective observational study of MT cases in La Réunion from 2012 to 2017. MT cases were defined as clinically compatible illnesses with a specific positive serology and/or PCR. RESULTS: Sixty-one confirmed cases were collected. The main clinical features were prolonged fever (90%), asthenia (87%), and headaches (79%). The main biological abnormalities were elevated liver enzymes (84%) and thrombopenia (75%). Renal function was normal in 90% of cases; it was an important feature because leptospirosis is a frequent cause of acute renal failure. A seasonal factor was observed with 79% of cases reported in the warm season and most of them in the west and south of the island (i.e., the dry areas). CONCLUSION: MT is an emerging disease in La Réunion, and local conditions could lead to an endemic situation. Cases of acute undifferentiated fever with headaches should guide to the diagnosis of MT especially in the warm season and dry areas. Leptospirosis is an alternative diagnosis, which differs from MT by its epidemiological characteristics and by the associated frequent renal dysfunction.

The University Hospital Institute Mediterrannée Infection from Marseille to Dakar.

In Senegal, we have developed technology-driven research based on observation and technology transfer especially in molecular biology, genomics, culturomics, and proteomics with the use of the first Maldi-TOF mass spectrometer in clinical microbiology in Africa. This strategy is associated with a policy of training students from the South and helping them to return back. This technology transfer and expertise has enabled us to explore the causes of non-malarial fevers of unknown causes, with the study of the repertoire of infectious pathogens in humans and arthropod vectors, to diagnose infectious diseases in rural areas with Point of Care laboratories, to isolate new bacteria, and to study pathologies linked to mass gatherings. They have also allowed us to develop transdisciplinary research including the study of the microbiota in malnourished children. We wish to continue this technological development, which provides the foundation for high-level research in Senegal.

Great apes in the emergence of infectious diseases.

Since the AIDS pandemic and the demonstration that it originated in the accidental transmission of simian retroviruses to humans, no one can ignore the role of nonhuman primates in carrying pathogens that can cross the species barrier to infect humans. In recent decades, viruses as deadly as those for rabies, Herpes B, Marburg hemorrhagic fever, and Ebola have been transferred from monkeys to humans. Because great apes are genetically our closest relatives, the pathogens that colonize these mammals are probably best adapted to pass into humans should accidental exposure occur. This article attempts to evaluate the risks of infection when apes and humans share the same ecosystem.

Limitations of diagnostic tests for bacterial infections.

Lyme disease diagnosis is currently based on serology - an indirect diagnostic method - as laboratory cultures are fastidious. The only direct diagnostic method that can be useful with some specimens (cutaneous biopsies or aspiration fluid) is PCR. We aimed to detail the main limitations of serology and PCR testing in the diagnosis of bacterial infections. Limitations are supported by examples from the recent history of microbiology. The main limitation of bacterial serology is the presence of numerous cross-reactions due to many genes that are common to various bacterial species. Some serological techniques, such as those used for the diagnosis of rickettsioses mainly, have even been based on the existence of cross-reactions. The main limitation of PCR testing is the potential presence of laboratory contaminations. PCR-performing laboratories must therefore be certified for the use of this technique. PCR testing also does not inform on the viability of the identified bacterium and should therefore be interpreted in light of the clinical presentation. These limitations highlight that all diagnostic test results should not be interpreted on their own; the clinical and epidemiological contexts should always be taken into consideration.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as a useful tool for the rapid identification of wild flea vectors preserved in alcohol.

Flea identification is a significant issue because some species are considered as important vectors of several human pathogens that have emerged or re-emerged recently, such as Bartonella henselae (Rhizobiales: Bartonellaceae) and Rickettsia felis (Rickettsiales: Rickettsiaceae). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been evaluated in recent years for the identification of multicellular organisms, including arthropods. A preliminary study corroborated the usefulness of this technique for the rapid identification of fleas, creating a preliminary database containing the spectra of five species of flea. However, longterm flea preservation in ethanol did not appear to be an adequate method of storage in the context of specimen identification by MALDI-TOF MS profiling. The goal of the present work was to assess the performance of MALDI-TOF MS in the identification of seven flea species [Ctenocephalides felis (Siphonaptera: Pulicidae), Ctenocephalides canis, Pulex irritans (Siphonaptera: Pulicidae), Archaeopsylla erinacei (Siphonaptera: Pulicidae), Leptopsylla taschenbergi (Siphonaptera: Ceratophyllidae), Stenoponia tripectinata (Siphonaptera: Stenoponiidae) and Nosopsyllus fasciatus (Siphonaptera: Ceratophyllidae)] collected in the field and stored in ethanol for different periods of time. The results confirmed that MALDI-TOF MS can be used for the identification of wild fleas stored in ethanol. Furthermore, this technique was able to discriminate not only different flea genera, but also the two congeneric species C. felis and C. canis.

Review of European and American guidelines for the diagnosis of Lyme borreliosis.

Lyme disease is a tick-borne bacterial disease with polymorphic clinical manifestations (cutaneous, rheumatological, and neurological). In recent years the issue of the diagnosis of this infection has been highly publicized on the Internet and other media in Europe and America. Some patients and physicians may share the perception that the diagnosis of the infection is not reliable in France. We reviewed current European and American guidelines on Lyme disease and performed a methodological evaluation of all guidelines. We retrieved 16 guidelines from seven countries. Our analysis revealed a global consensus regarding diagnosis at each stage of the infection. All guidelines indicate that the diagnosis is currently based on a two-tier serology at all stages of the infection, except for the early localized dermatological presentation known as Erythema migrans. One text of so-called guidelines has discordant recommendations when compared with the other guidelines, possibly explained by its low quality score. Contrary to the intense debate taking place on the Internet and in the European and American media, our analysis shows that the great majority of medical scientific guidelines with a high quality score, agree on the clinical diagnostic methods of Lyme disease.

Neglected vector-borne bacterial diseases and arboviruses in the Mediterranean area.

Arthropod vectors can transmit pathogenic microorganisms from one vertebrate to another during their blood meal. Although some vector-borne diseases have been eradicated in the Mediterranean area, such as malaria and dengue, recent endemic microorganisms (Toscana virus, Rickettsia spp.) remain neglected even though they cause many more cases. New diagnostic tools and innovative tools for the identification and characterization of vector species and microorganisms have been developed at IHU Méditerranée Infection, either internally or through collaborative and integrated projects. We have detected Rickettsia slovaca as a human pathogen and have described the disease; we have shown that Rickettsia felis can be transmitted by Anopheles mosquitoes; we have emphasized the increasing importance of bedbug (Cimex lectularius) as a potential vector of Bartonella quintana; and we have described the Toscana virus, a major agent of meningitis and meningoencephalitis which was disseminated in North Africa and Central and Eastern Europe, where it frequently cocirculates with a large number of newly described phleboviruses transmitted by sand flies.

Mobile populations across the Mediterranean Sea and beyond: travel medicine, mass gathering medicine and homeless health.

The Méditerranée Infection institute is internationally recognized for its expertise in infectious diseases and tropical medicine, and is one of the most active research centres for infectious diseases in Europe. Surveillance and research addressing infectious diseases in globally mobile populations is one of the strong components of the research conducted at the institute. A significant amount of clinical, microbiologic and epidemiologic works have been conducted in international travellers, pilgrims participating in large international religious gatherings, economic migrants and homeless migrant people over the last decades by our group. Our strong anchoring in several countries around the Mediterranean Sea and beyond, as well as the pivotal role of Marseille in the EuroTravNet and GeoSentinel international networks that monitor travel-associated diseases, reinforce our leading position in the fields of travel and tropical medicine, mass gathering medicine and homeless health.

Genotyping of Coxiella burnetii detected in placental tissues from aborted dairy cattle in the north of Algeria.

Coxiella burnetii, is an obligate intracellular bacterium which is present throughout the world. In humans, C. burnetii is the causative agent of Q fever. In cattle, the infection is suspected to cause stillbirths, retained fetal membranes, metritis and infertility. The birth products of ruminants shed huge amounts of bacteria, and are considered a major source for human infection. The present study was designed to search for the presence of C. burnetii in placental tissues collected from aborted and normal calving dairy cows in Algeria, using molecular tools. A total of 77 placental tissue fragments were collected from dairy cows. 73 samples were collected from aborted cows and four samples were collected from natural calving cows over a period of two years from January 2013 to March 2015. The presence of C. burnetii in these samples was screened by quantitative real-time polymerase chain reaction (qPCR) targeting two different genes, IS1111 and IS30 A. The positive PCR amplicons were subsequently sequenced for Multispacer Sequence Typing determination (MST) using seven pairs of sequences (Cox2, Cox5, Cox18, Cox37, Cox56, Cox57, and Cox61). Fourteen placental tissues (19.1%) were found to be positive for C. burnetii by qPCR; 9 (12.3%) from the city of Blida and 5 (6.84%) from the city of Medea. Genotyping of the corresponding amplicons displayed 100% identity with C. burnetii MST20 genotype, confirming the circulation of this clone in dairy farms from Algeria.

Escherichia coli spontaneous community-acquired meningitis in adults: A case report and literature review.

Gram-negative bacillary meningitis occurring post-trauma and following neurosurgical procedures has been described widely. However, reports of spontaneous cases are sparse, particularly community-acquired cases. Spontaneous community-acquired Escherichia coli meningitis is a rare (although increasingly seen) and specific entity that is poorly reported in the literature. A review of the literature identified only 43 cases of community-acquired E. coli meningitis reported between 1946 and 2016. This article describes two new cases of spontaneous community-acquired E. coli meningitis encountered in Marseille, France, and presents the results of a literature review on spontaneous community-acquired E. coli meningitis.

Comparative analysis of storage conditions and homogenization methods for tick and flea species for identification by MALDI-TOF MS.

Ticks and fleas are vectors for numerous human and animal pathogens. Controlling them, which is important in combating such diseases, requires accurate identification, to distinguish between vector and non-vector species. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was applied to the rapid identification of arthropods. The growth of this promising tool, however, requires guidelines to be established. To this end, standardization protocols were applied to species of Rhipicephalus sanguineus (Ixodida: Ixodidae) Latreille and Ctenocephalides felis felis (Siphonaptera: Pulicidae) Bouché, including the automation of sample homogenization using two homogenizer devices, and varied sample preservation modes for a period of 1-6 months. The MS spectra were then compared with those obtained from manual pestle grinding, the standard homogenization method. Both automated methods generated intense, reproducible MS spectra from fresh specimens. Frozen storage methods appeared to represent the best preservation mode, for up to 6 months, while storage in ethanol is also possible, with some caveats for tick specimens. Carnoy's buffer, however, was shown to be less compatible with MS analysis for the purpose of identifying ticks or fleas. These standard protocols for MALDI-TOF MS arthropod identification should be complemented by additional MS spectrum quality controls, to generalize their use in monitoring arthropods of medical interest.

Anti-feeding and insecticidal efficacy of a topical administration of dinotefuran-pyriproxyfen-permethrin spot-on (Vectra® 3D) on mice against Stegomyia albopicta (= Aedes albopictus).

An ectoparasiticide combining three active ingredients [dinotefuran, permethrin and pyriproxyfen (DPP)] was used in mice in an experiment designed to evaluate its anti-feeding and insecticidal efficacy against Stegomyia albopicta (= Aedes albopictus) (Diptera: Culicidae) mosquitoes. Twenty-two adult mice were randomly allocated into two groups consisting of an untreated control group and a DPP-treated group. Mice were exposed individually for 1 h to a mean ± standard deviation of 27 ± 2 starved female mosquitoes on days 1, 7, 14, 21 and 28 post-treatment. At the end of the exposure (1 h), mosquitoes were assessed for immediate survival and engorgement status. Additionally, live mosquitoes in both groups were incubated separately and observed for mortality at 24 h after the end of the exposure. The anti-feeding efficacy of DPP after the 1-h exposure period was 99.2, 100, 98.0, 89.3 and 87.4% at 1, 7, 14, 21 and 28 days, respectively. Levels of insecticidal efficacy evaluated at 1 h and 24 h after exposure on days 1, 7, 14, 21 and 28 were 36.7, 28.9, 30.8, 23.1 and 11.9%, and 68.4, 45.0, 43.3, 37.9 and 19.9%, respectively. Based on the mouse model, the present study demonstrates that the DPP combination has significant anti-feeding and insecticidal efficacy against S. albopicta for at least 4 weeks.

[Update on cutaneous dirofilariasis]. / La dirofilariose cutanée.

Dirofilariasis is a worldwide zoonotic infection that rarely affects humans and is caused by filarial nematodes of the genus Diroflaria transmitted by mosquitoes. Cutaneous dirofilariasis, due to D. repens, presents as inflammatory lesions that develop into subcutaneous nodules. These clinical symptoms may be consistent with Wells' cellulitis. Diagnosis of dirofilariasis involves demonstration of the presence of the nematode during skin biopsy and identification of the worm through macroscopic, histological and PCR analysis. Surgical resection of the nodule remains the gold standard treatment. The number of cases of human cutaneous dirofilariasis has increased in the recent years and the disease must not be misdiagnosed.