Oxidative metabolic profiles of Brucella strains isolated from marine mammals: contribution to their species classification

Since the 1990s, Brucella strains not matching the characteristics of any of the six conventional species have been isolated worldwide from marine mammals. In this study, 31 Brucella strains isolated from various marine mammals were examined for their oxidative metabolic pattern on 12 amino-acid and carbohydrate substrates. Three main oxidative profiles different from those of the Brucella terrestrial mammal strains were identified for the marine mammal strains: one gathering strains isolated from pinnipeds and two gathering strains from cetaceans. Thus, both oxidative metabolism results and previous molecular studies are in agreement with the proposal of two new Brucella species, Brucella pinnipediae and Brucella cetaceae, to classify the Brucella strains isolated from marine mammals, and are also in accordance with a classification of species of the Brucella genus based on host preference.     

Evaluation of Brucella MLVA typing for human brucellosis

Human brucellosis is still the most common bacterial zoonosis worldwide. Neither well-known molecular tools nor the classical biotyping methods are satisfactory for subtyping of Brucella spp. Loci containing Variable Number of Tandem Repeats (VNTRs) have recently proved their usefulness in typing strains from animal origin despite the high genetic homogeneity within the genus Brucella (DNA-DNA homology >90%). The aim of this study was to evaluate MLVA (Multiple Locus VNTR Analysis) for diagnostic and epidemiological use in human brucellosis. One hundred and twenty-eight B. melitensis isolates of all three biovars were typed using eight minisatellite (panel 1) and eight microsatellite (panel 2) markers. One hundred and ten different genotypes were identified. The MLVA clustering pattern correlated with the geographic origin of the strains. Brucella strains isolated from different patients within the same outbreak or from the same patient before first-line therapy and after relapse showed identical genotypes. Fuchsin sensitive B. melitensis strains were found in closely related clusters giving evidence for an association between VNTRs and some phenotypic characteristics. However, the validity of biovars established by classical microbiological methods could not be confirmed by MLVA clustering. The original data can be queried on the genotyping web page at http://bacterial-genotyping.igmors.u-psud.fr. The MLVA assay is rapid, highly discriminatory, and reproducible within human Brucella isolates. MLVA can significantly contribute to epidemiological trace-back analysis of Brucella infections and may advance surveillance and control of human brucellosis.     

The application of spectroscopy techniques for diagnosis of malaria parasites and arboviruses and surveillance of mosquito vectors: A systematic review and critical appraisal of evidence

Spectroscopy-based techniques are emerging diagnostic and surveillance tools for mosquito-borne diseases. This review has consolidated and summarised recent research in the application of Raman and infrared spectroscopy techniques including near- and mid-infrared spectroscopy for malaria and arboviruses, identified knowledge gaps, and recommended future research directions. Full-length peer-reviewed journal articles related to the application of Raman and infrared (near- and mid-infrared) spectroscopy for malaria and arboviruses were systematically searched in PUBMED, MEDILINE, and Web of Science databases using the PRISMA guidelines. In text review of identified studies included the methodology of spectroscopy technique used, data analysis applied, wavelengths used, and key findings for diagnosis of malaria and arboviruses and surveillance of mosquito vectors. A total of 58 studies met the inclusion criteria for our systematic literature search. Although there was an increased application of Raman and infrared spectroscopy-based techniques in the last 10 years, our review indicates that Raman spectroscopy (RS) technique has been applied exclusively for the diagnosis of malaria and arboviruses. The mid-infrared spectroscopy (MIRS) technique has been assessed for the diagnosis of malaria parasites in human blood and as a surveillance tool for malaria vectors, whereas the near-infrared spectroscopy (NIRS) technique has almost exclusively been applied as a surveillance tool for malaria and arbovirus vectors.Conclusions/SignificanceThe potential of RS as a surveillance tool for malaria and arbovirus vectors and MIRS for the diagnosis and surveillance of arboviruses is yet to be assessed. NIRS capacity as a surveillance tool for malaria and arbovirus vectors should be validated under field conditions, and its potential as a diagnostic tool for malaria and arboviruses needs to be evaluated. It is recommended that all 3 techniques evaluated simultaneously using multiple machine learning techniques in multiple epidemiological settings to determine the most accurate technique for each application. Prior to their field application, a standardised protocol for spectra collection and data analysis should be developed. This will harmonise their application in multiple field settings allowing easy and faster integration into existing disease control platforms. Ultimately, development of rapid and cost-effective point-of-care diagnostic tools for malaria and arboviruses based on spectroscopy techniques may help combat current and future outbreaks of these infectious diseases.     

Potent inhibition of sperm motility by palytoxin

Palytoxin, produced by a stationary marine animal and one of the most toxic substances known, was used as a spear poison in ancient Hawaii to cause death by cardiovascular contracture. We report here that the motility of hamster caudal epididymal (HCE) and other sperm can be inhibited by as little as 10⁻¹³ M palytoxin in a time-dependent manner. This inhibition manifested itself as a loss in flagellar amplitude, often accompanied by an increase in beat frequency, resulting in a loss of forward progression and ultimately cessation of movement. Similar effects were observed in sperm from guinea pigs, rabbit, cattle, sea urchins and man. Preincubation with palytoxin did not prevent the induction of motility from quiescence in HCE sperm when free calcium ion was added. However, regardless of the timing of palytoxin addition this very vigorous motility disappeared shortly after it appeared. These, plus earlier observations showing palytoxin did not cause lysis under similar conditions or inhibit the progressive motility of demembranated sperm axoneme preparations, suggest both that this large molecule acts via the plasma membrane to cause its exceedingly toxic effects and that spermatozoa may be useful for the investigation of the mechanism of action of palytoxin.     

Examining the Use of Mass Transplantation of Brooding and Spawning Corals to Support Natural Coral Recruitment in Sulawesi/Indonesia

Coral transplantation is frequently advocated as a possible means of coral reef rehabilitation. One of the purported benefits of transplantation is a positive effect of transplants on coral recruitment by sexual reproduction of transplants (“seeding”) and/or settlement cues generated by the presence of live coral (“attraction”). However, evidence for this assertion is scarce. Here, we investigated the effect of coral transplantation on larval recruitment. A total of 6,164 fragments of four coral species (acroporids and pocilloporids) were transplanted at three sites in North Sulawesi, Indonesia. Coral recruitment onto limestone settlement plates was examined every 3 months and on concrete structures at the end of the study (≥15 months) in the presence and absence of transplants. Transplant survival after 1 year ranged between 20 and 30% for pocilloporids and between 40 and 80% for acroporids. Transplantation had no consistent effect on the number of coral recruits on the settlement plates or on the concrete structures. Recruitment was relatively high compared to other locations in the region and fluctuated seasonally, with increased rates in all treatments during peaks of reproduction. We conclude that, in the presence of high background recruitment and detrimental environmental conditions, coral transplantation may not be an effective method to boost coral recruitment. The provision of stable substrate for settlement in the form of artificial reefs, combined with improved management to reduce chronic stressors, constitutes a better use of resources.     

Enhanced passive surveillance dengue infection among febrile children: Prevalence,co-infections and associated factors in Cameroon

Dengue virus (DENV) causes a spectrum of diseases ranging from asymptomatic, mild febrile to a life-threatening illness: dengue hemorrhagic fever. The main clinical symptom of dengue is fever, similar to that of malaria. The prevalence of dengue virus infection, alone or in association with other endemic infectious diseases in children in Cameroon is unknown. The aim of this study was to determine the prevalence of dengue, malaria and HIV in children presenting with fever and associated risk factors.Dengue overall prevalence was 20.2%, Malaria cases were 52.7% and HIV cases represented 12.6%. The prevalence of dengue-HIV co-infection was 6.0% and that of Malaria-dengue co-infection was 19.5%. Triple infection prevalence was 4.3%. Dengue virus infection is present in children and HIV-Dengue or Dengue- Malaria co-infections are common. Dengue peak prevalence was between August and October. Sex and age were not associated with dengue and dengue co-infections. However, malaria as well as HIV were significantly associated with dengue (P = 0.001 and 0.028 respectively). The diagnosis of dengue and Malaria should be carried out routinely for better management of fever.