ETUDE DE LA NUISANCE DES MOUSTIQUES EN MILIEU UNIVERSITAIRE DE LA FACULTE DES SCIENCES ET TECHNIQUES, BAMAKO, MALI

Mosquitoes are potentially harmful and vectors of pathogens. They compromise the rest and well-being of humans and animals. The main goal of this study is to determine the composition of mosquitoes responsible of human biting at the Faculty of Sciences and Technics of Bamako-Mali. Longitudinal monitoring with monthly cross-sectional visit was carried out from September to December 2019, in order to collect the endophilic and endophagic mosquitoes. The spray-catch was used as a collection methodin 21 rooms selected randomly at the FST. Mosquitoes were identified morphologically andthen by PCR. ELISA-CSP test was used for Plasmodium infection index and the ELISA blood-meal test was to determine mosquitoes blood origin. In total, 802 mosquitoes were collected: 794Culex and 8Anopheles. There were 200 males and 602 females. Female mosquitoes were separated by gonotrophic stages: 231 unfed, 223 fed, 80 semi-gravid and 68 gravid. Up to 34% of Culex and 67% of Anopheles had a preference for human blood, but no female tested positive for Plasmodium infection. This result would be due to the small number of Anopheles captured. An. coluzzii is the only Anopheles species collected.This study shows that mosquitoes are linked to serious problems of nuisance and risk of pathogens transmission in the university. They highly prefer to feed on human host.

Composite Bacterial Infection Index and Serum Amyloid A Protein in Pulmonary Tuberculosis Patients and their Household Contacts in Makassar

BACKGROUND: Early diagnosis of tuberculosis (TB) cases in limited resource remains challenging. It is urgent to identify the new diagnostic tools which can control the spread of disease with accurate and rapid test. AIM: This study aimed to investigate the levels of infection markers: Composite bacterial infection index (CBII) and serum amyloid A (SAA) protein in pulmonary TB (PTB), and their healthy household contacts, as the alternative diagnostic markers for TB. METHODS: CBII and SAA were measured from 44 new PTB patients, and 31 household contact serum samples. The value of CBII was calculated from neutrophils, lymphocytes, monocytes, erythrocyte sedimentation rate, and high-sensitivity C-reactive protein (hs-CRP) level. hs-CRP and SAA levels were quantified from their serum samples using ELISA. QuantiFERON-TB Gold Plus (interferon gamma release assay [IGRA]) was used to screen latent TB infection among household contacts. RESULTS: Among 31 household contacts, there were 24 positive IGRA results and the rest (n = 7) had negative results. PTB patients exhibited significantly higher level CBII in the serum specimens, than those in household contact (p < 0.0001). There was no significant difference in the SAA level between TB cases and household contacts (p = 0.679). CONCLUSIONS: CBII can be used as one of the biomarkers for the identification of PTB from the serum specimens.

An estimative (warning) model for recognition of pandemic nature of virus infections

A simple SIS-type mathematical model of infection expansion is presented and analysed with focus on the case SARS-Cov-2. It takes into account two processes, namely, infection and recovery/decease characterised by two parameters in total: contact rate and recovery/decease rate. Its solution has a form of a quasi-logistic function for which we have introduced an infection index that, should it become negative, can also be considered as a recovery/decease index with decrease of infected down to zero. Based on the data from open sources for the SARS-Cov-2 pandemic, seasonal influenza epidemics and a pandemic in the fauna world, a threshold value of the infection index has been shown to exist above which an infection expansion pretends to be considered as pandemic. Lean (two-parameter) SIR models affined with the warning SIS model have been built. Their general solutions have been obtained, analysed and shown to be a priori structurally adjusted to the infectives’ peak in epidemiological data.

Survival and dispersal of brucella vaccine strain brucella abortus 19 in the body of vaccinated animals

In the general complex of antibrucellosis measures, specific prevention of the disease occupies an important place. The first experiments on vaccination of animals against brucellosis were carried out in the early 20th century. Experiments have shown that even a single subcutaneous vaccination with a live virulent culture 2 months before fertilization in 90% of cases protects animals from subsequent infection and abortion. Of all the brucellosis vaccines used in different countries, the most widespread is the vaccine from the B. abortus 19 strain, which is used to prevent brucellosis in all farm animals. When studying the dispersal and survival of brucella of the vaccine strain in the body of animals vaccinated with different doses of the vaccine, it proceeded similarly, without significant difference (P>0,05). The infection index in heifers vaccinated with a small dose 1 month after vaccination was 60±2, and in heifers vaccinated with a full dose - 74±4. Two months after vaccination, the infection index was 44±16 and 44±4, respectively. 2 months after vaccination, the total number of isolated cultures was 21% less than in the study 1 month after vaccination. According to the total data, 38.5% of cultures were sown from the pharyngeal and prescapular lymph nodes of heifers vaccinated with a small dose 1 month after vaccination, and 20% after 2 months. In heifers vaccinated with a full dose, 28.1% and 26.9%, respectively. Thus, the results of the experiment showed that the dispersibility and survival rate of brucella vaccine strain B. abortus 19 in the body of heifers slightly depends on the dose of the vaccine, which is consistent with the data obtained by us in the experiment on guinea pigs, as well as with the data of other authors.

The Role of Air Conditioning in the Diffusion of Sars-CoV-2 in Indoor Environments: a First Computational Fluid Dynamic Model, based on Investigations performed at the Vatican State Childrens Hospital.

Background: About 15 million people worldwide were affected by the Sars-Cov-2 infection, which already caused 600,000 deaths. This virus is mainly transmitted through exhalations from the airways of infected persons, so that Heating, Ventilation and Air Conditioning (HVAC) systems might play a role in spreading the infection in indoor environments. Methods: We modelled the role of HVAC systems in the diffusion of the contagion through a Computational Fluid Dynamics (CFD) simulations of cough at the Vatican State childrens hospital Bambino Gesu. Both waiting rooms and hospital rooms were modeled as indoor scenarios. A specific Infection-Index parameter was used to estimate the amount of contaminated air inhaled by each person present in the simulated indoor scenarios. The potential role of exhaust air ventilation systems placed above the coughing patients mouth was also assessed. Results: Our CFD-based simulations show that HVAC air-flow remarkably enhance infected droplets diffusion in the whole indoor environment within 25 seconds from the cough event, despite the observed dilution of saliva particles containing the virus. In the waiting room simulation, Infection-Index parameter increases the faster the higher the HVAC airflow. Greater flows of air conditioning correspond to greater diffusion of the infected droplets. The proper use of Local Exhaust Ventilation systems (LEV) simulated in the hospital room was associated to a complete reduction of infected droplets spreading from the patient s mouth in the first 0.5 seconds following the cough event. In the hospital room, the use of LEV system completely reduced the index computed for the patient hospitalized at the bed next to the spreader, with a decreased possibility of contagion. Conclusions: CFD-based simulations for indoor environment can be useful to optimize air conditioning flow and to predict the contagion risk both in hospitals/ambulatories and in other public/private settings.

PARASITES IN VOLES AT THE TERRITORY AROUND MAHNEVSKAYA ICE CAVE (PERM REGION)

Present study was carried out for the investigation of mammalians parasites formation in the territory of West Siberia and Ural. The analysis of parasitophauna of tundra vole (13 examples) and bank vole (20 examples) obtained from the territory around Mahnevskaya Ice Cave at the North of Perm region was performed. Corpses of rodents was investigated by the method of partial helminthological dissection. As a result, a distribution of intestinal helminthes at 38,46% in Microtus oeconomus and 20,0% in Myodes glareolus is found. The tundra vole is most infested by Notocotylus noyeri with an infection level at the 23.08% and Anoplocephalidae sp. with an infection index at the 15.38%. Hymenolepidid Cestodes are revealed only in the bank vole. All detected parasites are specific to voles of these species. That low level of infection as like an absence of parasites eggs in micromammalian coprolites from Midholocene cave sediments let conclude about comparatively recent establishment of parasitoses in two species of voles at the territory.

Susceptibility of Toxoplasma gondii to Ethanolic Extract of Tinospora crispa in Vero Cells

Background. Toxoplasmosis remains widely distributed globally and is one of the major neglected parasitic zoonotic infections. The infection is still endemic in most parts of the world due to poor control as well as challenges of the currently used medications which can be overcome by using natural products. This study evaluated the effect of ethanolic extract from the stem of Tinospora crispa (EETC) on host cell invasion and intracellular replication of Toxoplasma gondii. Method. The stem powder of T. crispa was soaked in absolute ethanol for 72 hours. The resulting ethanolic extract was screened for the presence of phytochemicals. Vero cells monolayer in 96-well plate was infected with RH strain of T. gondii and treated with concentrations of the EETC, Veratrine alkaloid, and clindamycin ranging from 1.56 to 200 μg/mL. MTT assay was conducted after 24 hours to evaluate the cytotoxicity and antiparasitic activities of the EETC. Four and 24 hours treatment models were adapted to assess the infection index and intracellular proliferation of T. gondii in vitro. Microscopic analysis was conducted after 24 and 48 hours exposure to EETC in both treatment models. Results. The study revealed that the EETC had no cytotoxic effects on Vero cells with IC50 = 179 μg/mL, as compared to clindamycin (IC50 = 116.5 μg/mL) and Veratrine alkaloid (IC50 = 60.4 μg/mL). The EETC had good anti-toxoplasma activities with IC50 = 6.31 μg/mL in comparison with clindamycin (IC50 = 8.33 μg/mL) and Veratrine alkaloid (IC50 = 14.25 μg/mL). The EETC caused more than 70% and 80% reduction in infection index and intracellular proliferation in both treatment models, respectively. Conclusion. This in vitro study showed that the EETC contains promising phytochemicals effective against T. gondii and safe to the host cells.

Galactosyl and sialyl clusters: synthesis and evaluation against T. cruzi parasite

The multivalent effect of carbohydrates (glycoclusters) has been explored to study important biological targets and processes involvingTrypanosoma cruzi(T. cruzi) infection. Likewise, CuAAC cycloaddition reactions (click chemistry) have been applied as useful strategy in the discovery of bioactive molecules. Hence, we describe the synthesis of 1,2,3-triazole-based tetravalent homoglycoclusters (1–3) and heteroglycoclusters (4and5) ofd-galactopyranose (C-1 and C-6 positions) and sialic acid (C-2 position) to assess their potential to inhibitT. cruzicell invasion and also its cell surfacetrans-sialidase (TcTS). The target compounds were synthesised in good yields (52–75 %)viaclick chemistry by coupling azidosugars galactopyranose and sialic acid with alkynylated pentaerythritol or tris(hydroxymethyl)-aminomethane (TRIS) scaffolds.T. cruzicell invasion inhibition assays showed expressive low parasite infection index values (5.3–6.8) for most compounds. However, most glycoclusters proved to be weak TcTS inhibitors at 1 mM (<17 %), except the tetravalent sialic acid3(99 % at 1 mM, IC50450 μM). Therefore, we assume thatT. cruzicell invasion blockage is not due to TcTS inhibition by itself, but rather by other mechanisms involved in this process. In addition, all glycoclusters were not cytotoxic and had significant trypanocidal activity upon parasite survival of amastigote forms.