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Jul 2023 DOI 10.14302/issn.2643-2811.jmbr-23-4556
The present work shows that it is possible to analytically solve a general model to explain the transmission dynamics of SARS-CoV-2. First, the within-host model is described, and later a between-host model, where the coupling between them is the viral load of SARS-CoV-2. The within-host model describes the equations involved in the life cycle of SARS-CoV-2, and also the immune response; while that the between-Host model analyzes the dynamics of virus spread from the original source of contagion associated with bats, subsequently transmitted to a host, and then reaching the reservoir (Huanan Seafood Wholesale Market in Wuhan ), until finally infecting the human population.
Dec 2022 DOI 10.14302/issn.2690-6759.jpar-22-4382
Background Intestinal parasitic infections, especially intestinal protozoan parasites remain significant public health problem in Senegal. Several studies have demonstrated the endemicity of the diseases. The study was carried out with the objective of assessing the epidemiolocal profile of intestinal protozoan infection diagnosed among patients attending to Fann University Hospital in Dakar, Senegal. Materials and Method A retrospective study was conducted from 2016 to 2020. Samples were collected from patients attending to the laboratory for parasitological confirmation. Fresh stool samples were observed using direct examination, formal-ether concentration method and modified Zeilh Nielsen staining method. Descriptive analysis was performed using Stata MP 16 software. The significance level was set at 5%. Results Among 3825 patients selected in the study, 1009 were found with at least one intestinal protozoan parasite representing an overall prevalence of 26.4% (CI 95% (24.7– 28)). Mono-parasitic and di-parasitic infection represent 81.6% and 18.2% respectively while polyparasitism was observed in 26 patients representing 2,6%. Among positive samples, 16 (8.7%) were associated with helminths. Blastocystis sp. (40.8%), Entamoeba Coli (38.2%), Endolimax nana (8.2%) and Giardia intestinalis (8.1%) were mainly observed. Trophozoites Entamoeba histolytica was observed with 2.3%. Frequency of intestinal protozoa was higher in the 15 – 30 age group (28.3%) and in male group (26.9%). The parasite carriage was most important during the wet season comparing the dry season (p = 0.65). Asymptomatic patients (29.5%) were more infected than symptomatic patients (23.5%) (p <10-3). The main clinical symptoms were diarrhea, abdominal pain, dysenteric syndrome, fever, dyspeptic disorders, and vomiting. Conclusion These results showed that intestinal protozoan infections remain prevalent in Senegal with a high proportion of asymptomatic who constitute an important reservoir of parasites. Effective control strategies such as water supply, hands washing, and mass deworming campaign could reduce the prevalence of these diseases.
Feb 2021 DOI 10.14302/issn.2692-1537.ijcv-21-3732
This paper resolves analytically a mathematical model that reproduces the transmission of Covid-19 in three interactive populations, i.e. from the initial source of contagion associated with the bat population, subsequently transmitted to unknown host (usually associate with pangolins). The host were sent and distributed to Seafood Market in Wuhan (defined reservoir), and finally infected to the human population. The model is based on a system of ten differential equations reproducing all the possible infection scenarios among all of them, that is: (1) there is no infection in any of the three populations, (2) only the population of bats is infected, (3) only the pangolins, (4) only the human people. Later, combinations between them, this is: (5) both the bat and pangolin populations, (6) bats and humans, (7) pangolins and humans, and finally, (8) all the previous populations. In each scenario, I deduced the critical points as well as the eigenvalues that indicate the equilibrium conditions. Finally, it is demonstrated the validity of the model with the data corresponding to the second wave of infections in Australia.
May 2020 DOI 10.14302/issn.2692-1537.ijcv-20-3344
Identifying the epidemiological characteristics of COVID-19 disease will help to make appropriate decisions and thus control the epidemic. Although many details, such as the source of the virus and its ability to spread between people remain unknown, an increasing number of cases show the signs of human-to-human transmission. The purpose of this review is to introduce the reservoir hosts, and the possible role of distributions of bat coronaviruses in China, and eventually to aim to predict virus natural hotspots and their cross-species transmission potential. Why bats can maintain coronaviruses long-term without showing clinical symptoms of diseases and what is allowing bats to have a higher tolerance against viral diseases. We need to unveil the mystery of unique bat immunity. Although bats are not in close contact with humans, spillover of viruses from bats to intermediate animal hosts like civet is thought to be the most likely mode to cause human infection. It appears that the coffee beans which are a rich source of chlorogenic acid are acting as a reservoir host and causative agent, and at the same time as a defense agent to create resistance in the consumers (bats and animals). It is assumed that the intake of chlorogenic acid should be capable of protecting human from contamination or severe morbidity.
Feb 2020 DOI 10.14302/issn.2690-6759.jpar-20-3184
Domestic pigeons (Columba liviadomestica) of the order Columbiformes are ubiquitous birds and can be found in virtually every town and city around the globe. Their interaction with humans and domestic animals and wild birds makes them a potential carrier of zoonotic parasites. The present study aimed to detect the prevalence of different zoonotic protozoans that affect different-aged domestic pigeons in different localities in Assiut Governorate, Egypt. A total of 50 fecal samples from 20 young and 30 adult pigeons were collected and examined for identification and estimation of prevalence of Cryptosporidium sp. and Microsporidium sp. using modified Kinyoun acid-fast stain. For detection of the prevalence of Toxoplasma gondii, serum samples from 50 pigeons were examined serologically for the presence of Toxoplasma antibodies by using Latex Agglutination test. The prevalence of Cryptosporidium sp. infection was 20%; 6.7% in adult pigeons and 40 % in young pigeons while that of Microsporidium sp. was 40% both in adult and young pigeons. Mixed infection was detected in only two young pigeons (10%). Regarding Toxoplasma gondii detection, the number of seropositive cases detected by LAT was 29 out of 50 (58%). The positive agglutination titers, among 14 (48.27%) seropositive pigeons ranged between 1:2 -1:128. It was concluded that domestic pigeons may be considered as a reservoir host for Cryptosporidium, Microsporidium, and Toxoplasmagondii human infection which represents a serious human public health problem especially for high risk groups of population living in the same dwellings with pigeons. Moreover, the present pilot results provide a baseline data for planning future researches and control strategies against domestic pigeon's parasites.
Oct 2019 DOI 10.14302/issn.2639-3166.jar-19-3015
Monsoon rains provide relief from the sweltering summer heat conditions, replenish depleted profile moisture to breathe new life in soils. With appropriate management of rain water, Indian summer monsoons boost the level of ‘reservoir of life’. Our inability to manage spatial and temporal rainfall variation features of deficit and excess rainfall episodes and their interactions with soil variability is a major cause of uncertainty in agricultural production. In the past, entire focus of national efforts was on rainwater harvesting, storage and distribution through canal networks and greater reliance on ground water pumping to meet immediate crop water demands. These approaches have resulted in wide spread problems of natural resource fatigue and unsustainable water supplies. This paper analyses the complexities of climate change-land degradation-food security nexus and suggests the need for adopting alternate approaches emphasising on in situ conservation of rain water and its efficient use such as to reverse the processes that contribute to land degradation in specific landscapes.
May 2019 DOI 10.14302/issn.2328-0182.japst-19-2738
Rationale Prisons are major reservoirs of hepatitis C virus (HCV) in which a therapeutic approach has been particularly difficult so far. Prevalence of viral hepatitis C (HCV) is higher in prison environment in France than in the general population and is estimated to be 4,8%. The impact in prison environment is little-known as based on local studies. Inmate health care falls under USMP (prison setting medical unit), hospital specific units as by the january 18, 1994 law. Access to antiviral c treatment for inmates has always been difficult in France, would it be for interferon and ribavirin or use of protease inhibitors, with less than 20% of treated patients. French recommendations for HCV screening recommend systematic screening of inmates. The arrival of all oral therapies by direct antiviral agents (DAA) with shorter treatment times was an opportunity for doctors to propose a treatment and the patient to accept it. In 2014, the French guidelines recommended that HCV carriers in prison should systematically be treated independently of the stage of fibrosis. Objective of the Study PH8 Our objective was to evaluate the completion rate of an 8-week antiviral C treatment by sofosbuvir / ledipasvir regimen in non-cirrhotic genotype 1 patients in deprivation of liberty and achieve sustained virological response (SVR) and to measure the effectiveness of an 8-week treatment (by protocol analysis). Methodology prospective non-interventional multicenter trial among inmates with chronic hepatitis C genotype 1 with METAVIR fibrosis score F0 to F2 and who will receive a daily combination of sofosbuvir / ledipasvir for 8 weeks. Results 6 prison medical units included 115 consenting patients: there were 81% men, mean age 41 years (21 to 64 years). Route contamination was drug injection for 85%. HCV genotype was 1a for 74%, 1b for 24% and 2% none differenciated 1. Fibroscan mesure was available in 89 patients (mean score 3,5 KPa). Fibrotest was available in 37 patients with mean value 0.21. Eleven patients had Fibroscan and Fibrotest; 69% of patients were F0, 22% F1 and 9% F2. Average time between diagnosis and start of treatment was 3 weeks. We are sure that 109 patients (95%) completed DAA 8 weeks treatment; only 2 stopped DAA treatment before 8 weeks and 4 had no follow up after end of detention. HCV viral load was measured at W2 for 90 patients (78%), at W4 for 92 patients (78%), at end of treatment for 92 patients (78%), one month after treatment for 90 patients (78%) and 3 months after for 95 patients (93%). Only one viral load was positive, one month after treatment. Patient was retreated by sofosbuvir / velpastasvir. All HCV viral load 3 months after treatment negative; one patient took DAA only 6 weeks was cured. Conclusions In these study PH8, we observed completion rate of 94% for included patients in patient with 8 weeks ledipasvir/sofosbuvir regimen; data missed for only 4 patients and one relapsed. Short DAA treatment was efficient in prisoners and could be preferred in specific population.
Apr 2019 DOI 10.14302/issn.2377-2549.jndc-19-2720
Currently, enhanced oil recovery (EOR) acquire increased attention to recover more residual oil trapped after the primary and secondary process in petroleum reservoirs. EOR comprise different technologies involving chemical, thermal, miscible flooding techniques. Chemical flooding by the polymer is a widely implemented method on the academic and industrial scale. In this chapter, the authors discuss polymer flooding using polyacrylates that involve hydrolyzed polyacrylamide (HPAM), hydrophobically associated polyacrylamides (HAPAM), which grafted with different vinyl monomers such as acrylic acid, methyl methacrylates, and 2-acrylamido-2-methylpropane sulfonic acid (AMPS). These polymers increase the viscosity of injected brine solutions, as a result, decrease mobility ratio and enhance sweeping efficiency, so the water act as a piston, which pushes oil in front of it, and consequently increase the recovery factor. The advantages and disadvantages of these polymers as well as comparing different flooding scenarios are reported.
Jan 2019 DOI 10.14302/issn.2690-6759.jpar-18-2510
Bancroftian filariasis (BF) is a debilitating disease that has plagued Egypt since the time of the pharaohs. Egypt is the first large endemic country in the world to reach the five-year mark in its national campaign. Now that the mass treatments are completed, a follow-up epidemiological assessment will reveal whether this large-scale, pioneering campaign has been successful in finally eliminating the disease. Hence the aim of the present work was to detect the prevalence of bancoftian filariasis in Tema, El-Maragha, Akhmeem and Girga districts in Sohag Governorate, Upper Egypt. Finger prick thick blood films were randomly collected from 500 clinically suspected individuals representing different sexes and ages suffering from lower limb non-pitting edema and/or inguinal lymphadenitis from May 2015 to February 2017. Three patients (0.6%) were infected with microfilariae of Wuchereria bancrofti while one chronic case was detected with severe chronic elephantiasis that was amicrofilaraemic but was confirmed serologically. Results were discussed in regards of age, gender, occupation, locality and residence. It was concluded that bancroftian filariasis is still endemic in three districts (Tema, El- maragha and Girga). Although in sporadic few cases, the problem should be taken seriously as one microfilaramic patient could be a patent reservoir for spreading of the disease through infecting the prevailing Culex pipiense mosquito intermediate host.
Aug 2017 DOI 10.14302/issn.2575-1212.jvhc-17-1661
Serum samples from wild and domestic South American Camelids (SAC) from Argentina, collected before (2008), during (2009) and after (2010) the 2009 H1N1 influenza pandemic were tested by hemagglutination-inhibition assay (HIA) to evaluate the seroprevalence of antibodies (Ab) against different subtypes of influenza A viruses: A(H1N1)pdm09, A/sw/Argentina/SIV/2009(H3N2) and A/eq/Argentina/97(H3N8). For A(H1N1), an ELISA using a recombinant H1-hemmaglutinin from a reference strain (HA0 PuertoRico/8/1934) was also conducted. Serum samples from Guanacos (126), vicugnas (21) and llamas (100) from Jujuy, Mendoza and Río Negro provinces were analyzed; no clinical signs of respiratory disease were detected, reason for which no nasal swabs were obtained. No seropositive reactors to H3N2 nor H3N8 variants were detected, nevertheless high incidence of Ab reactive to A(H1N1)pdm09 were found by HIA; results which were confirmed by ELISA. The Ab seropositive animals to H1-like IAV found in llamas from Jujuy, and Mendoza (2009) were 78% and 86% by HIA and ELISA, respectively. Thirty-seven samples taken over the three years from guanacos kept in captivity in Rio Negro showed 62% of seropositive animals, while wild guanacos from Mendoza sampled in 2010 showed 36% seropositive animals to H1-like IAV, by both techniques. Finally, wild vicugnas from Jujuy, sampled in 2008 showed 38% and 52% seropositive animals to H1-like IAV by HIA and ELISA, respectively. Our results could indicate the potential role of these species as a reservoir of this zoonotic viral agent of high impact in Public Health, and may suggest that SAC populations might have been infected with an influenza strain antigenically related to H1 IAV. . Surprisingly, for llama and guanaco populations sampled over time in Jujuy and Río Negro, respectively, the HIA and ELISA geometric mean Ab titers (GMT) for 2008 were significantly higher than the ones of 2010. In addition, HIA and ELISA Ab titers found in domestic llamas were significantly higher than those detected in wild vicugnas sampled during that year (2008) in Jujuy. New field campaigns are in progress to collect serum samples and nasal swabs in order to isolate and characterize the virus responsible for triggering H1 reactive Abs. These findings remark the need to better understand the dynamics and ecology of influenza A virus within Sacs populations.
May 2017 DOI 10.14302/issn.2470-0436.jos-17-1453
Purpose: High intraocular pressure (IOP) is known to result in retinal ganglion cell (RGC) loss, both with chronically raised intraocular pressure (such as with glaucoma) and with acute raises in pressure (due to injury or acute angle closure). Because IOP is often raised during ocular surgery, the purpose of this study was to evaluate the effect of transient moderate IOP on retinal function, RGC survival and the expression of Connexin 43 (Cx43) and glial fibrillary acidic protein (GFAP), ubiquitously expressed central nervous system (CNS) proteins that are known to be elevated during the retinal inflammatory response to injury. Materials and Methods: Wistar rats were exposed to transient IOP at 40 mmHg for 5 or 30 minutes, and 60 mmHg for 5 minutes (via cannulation of the anterior chamber with a saline reservoir raised to a height corresponding to the desired IOP), mimicking potential IOP rises during surgery such as DSAEK and some laser procedures (LASIK and femtosecond laser cataract surgery). Separate groups of animals had IOP maintained at 10 mmHg for 5 or 30 minutes as cannulation controls, or 120 mmHg for 60 minutes as positive controls. Changes in the optic nerve and retina were assessed immunohistochemically for GFAP and Cx43 expression. Retinal function was assessed using electroretinography (ERG) recorded at baseline and 14 days after the IOP rise and compared with RGC counts. Results: Results showed that there was a differential GFAP labelling pattern observed in the anterior optic nerve in the 40 mmHg 30 minute and 60 mmHg 5 minute groups 4 hours after manipulation. Gap junction protein Cx43 was minimally up-regulated in the retina in the short-term. There was, however, minimal long-term effect on retinal function and no RGC loss. Conclusions: n conclusion, elevations of IOP that are short in duration such as those occurring during surgical procedures, do not cause significant changes long-term in retinal function or RGC survival. Key Messages: Cx43 and GFAP are known to be elevated during the retinal inflammatory response to injury. No previous study has explored the effect of moderate and relatively short increases in IOP on the initial inflammatory response. We observed a mild glial inflammatory response in the anterior optic nerve, but only a minimal up-regulation of Cx43. However, transient and moderate IOP rises did not induce long term disruption to RGC function or number as measured by electrophysiology and RGC counts, respectively. This is applicable to clinical practice, as it means the IOP elevations that occur during some surgical procedures are unlikely to be causing long term damage in retinal function or RGC survival.