Showing papers in "Pathogens and Global Health in 2020"

The global spread of 2019-nCoV: a molecular evolutionary analysis.

Abstract: The global spread of the 2019-nCoV is continuing and is fast moving, as indicated by the WHO raising the risk assessment to high. In this article, we provide a preliminary phylodynamic and phylogeographic analysis of this new virus. A Maximum Clade Credibility tree has been built using the 29 available whole genome sequences of 2019-nCoV and two whole genome sequences that are highly similar sequences from Bat SARS-like Coronavirus available in GeneBank. We are able to clarify the mechanism of transmission among the countries which have provided the 2019-nCoV sequence isolates from their patients. The Bayesian phylogeographic reconstruction shows that the 2019-2020 nCoV most probably originated from the Bat SARS-like Coronavirus circulating in the Rhinolophus bat family. In agreement with epidemiological observations, the most likely geographic origin of the new outbreak was the city of Wuhan, China, where 2019-nCoV time of the most recent common ancestor emerged, according to molecular clock analysis, around November 25th, 2019. These results, together with previously recorded epidemics, suggest a recurring pattern of periodical epizootic outbreaks due to Betacoronavirus. Moreover, our study describes the same population genetic dynamic underlying the SARS 2003 epidemic, and suggests the urgent need for the development of effective molecular surveillance strategies of Betacoronavirus among animals and Rhinolophus of the bat family.

Knowledge of human monkeypox viral infection among general practitioners: a cross-sectional study in Indonesia.

Abstract: After the first, imported, laboratory-confirmed case of monkeypox in human was reported in Singapore on May 2019, countries in Asia started to strengthen disease surveillance systems. One challenge...

Decreased in-hospital mortality in patients with COVID-19 pneumonia.

Abstract: Clinical manifestations of COVID-19 may range from asymptomatic to severe interstitial pneumonia with acute respiratory distress syndrome (ARDS) and death COVID-19 mortality rates vary greatly [1]

Is glucose-6-phosphate dehydrogenase enzyme deficiency a factor in Coronavirus-19 (COVID-19) infections and deaths?

Abstract: The coronavirus (COVID-19) pandemic has become today’s most important world public health problem. As of 30 March 2020, World Health Organization (WHO) has reported 638,146 confirmed cases and 30,0...

Impact of COVID-19 public health interventions on influenza incidence in Thailand.

Abstract: The global outbreak of the 2019 novel coronavirus disease (COVID-19), as of 1 June 2020, has surpassed 6 million infections, and has resulted in over 370,000 deaths in the first five months of 2020...

The impact of climate change on mosquito-borne diseases in Africa.

Abstract: Despite being one of the continents with the least greenhouse gas emissions, no continent is being struck as severely by climate change (CC) as Africa Mosquito-borne diseases (MBD) cause major human diseases in this continent Current knowledge suggests that MBD range could expand dramatically in response to CC This study aimed at assessing the relationship between CC and MBD in Africa Methods For this purpose, a systematic peer review was carried out, considering all articles indexed in PubMed, Scopus, Embase and CENTRAL Search terms referring to MBD, CC and environmental factors were screened in title, abstract and keywordsResults A total of twenty-nine studies were included, most of them on malaria (61%), being Anopheles spp (61%) the most commonly analyzed vector, mainly in Eastern Africa (48%) Seventy-nine percent of these studies were based on predictive models Seventy-two percent of the reviewed studies considered that CC impacts on MBD epidemiology MBD prevalence will increase according to 69% of the studies while 17% predicted a decrease MBD expansion throughout the continent was also predicted Most studies showed a positive relationship between observed or predicted results and CC However, there was a great heterogeneity in methodologies and a tendency to reductionism, not integrating other variables that interact with both the environment and MBD In addition, most results have not yet been tested A global health approach is desirable in this kind of research Nevertheless, we cannot wait for science to approve something that needs to be addressed now to avoid greater effects in the future

Methicillin Resistant Staphylococcus aureus and public fomites: a review.

Abstract: Staphylococcus genus is a Gram-positive coccus normally associated with skin and mucous membranes of warm-blooded animals. It is part of the commensal human microflora, or found in animals, or cont...

Design of a multi-epitope subunit vaccine for immune-protection against Leishmania parasite.

Abstract: Visceral Leishmaniasis (VL) is an insect-borne neglected disease caused by the protozoan parasite Leishmania donovani. In the absence of a commercial vaccine against VL, chemotherapy is currently the only option used for the treatment of VL. Vaccination has been considered as the most effective and powerful tool for complete eradication and control of infectious diseases. In this study, we aimed to design a peptide-based vaccine against L. donovani using immuno-bioinformatic tools. We identified 6 HTL, 18 CTL, and 25 B-cell epitopes from three hypothetical membrane proteins of L. donovani. All these epitopes were used to make a vaccine construct along with linkers. An adjuvant was also added at the N-terminal to enhance its immunogenicity. After that, we checked the quality of this vaccine construct and found that it is nontoxic, nonallergic, and thermally stable. A 3D structure of the vaccine construct was also generated by homology modeling to evaluate its interaction with innate immune receptors (TLR). Molecular docking was performed, which confirmed its binding with a toll-like receptor-2 (TLR-2). The stability of vaccine-TLR-2 complex and underlying interactions were evaluated using molecular dynamic simulation. Lastly, we carried out in silico cloning to check the expression of the final designed vaccine. The designed vaccine construct needs further experimental and clinical investigations to develop it as a safe and effective vaccine against VL infection.

Chikungunya fever in Africa: a systematic review

Abstract: Since the identification of chikungunya virus (CHIKV), sporadic cases and outbreaks were reported in several African countries, on the Indian subcontinent, and in south-east Asia. In the last 20 ye...

Potential of the natural products against leishmaniasis in Old World - a review of in-vitro studies.

Abstract: Leishmaniasis is a vector-borne disease among the 10 most Neglected Tropical Diseases with diverse clinical manifestations caused by protozoan parasites of the Leishmania genus. Around 80% of leishmaniasis cases are found in the Old World affecting populations mainly in low and middle-income countries. Its control relies mostly on chemotherapy which still presents many drawbacks. Natural products may offer an inexhaustible source of chemical diversity with therapeutic potential. Despite the lack of knowledge on traditional products with activity against Leishmania parasites, many reports describe the search for natural extracts and compounds with antileishmanial properties against promastigote and amastigote parasite forms. This review summarizes the research of 74 publications of the last decade (2008-2018) focused on the identification of endemic plant-derived products that are active against Old World Leishmania parasites responsible for cutaneous and visceral leishmaniasis. The present review combines data on antileishmanial activity of 423 plants species, belonging to 94 different families, including a large range of crude extracts which lead to the isolation of 86 active compounds. Most studied plants came from Asia and most promising plant families for antileishmanial activity were Asteraceae and Lamiaceae. From the chemical point of view, terpenoids were the most frequently isolated natural products. These studies suggest that natural products isolated from Old World flora are a rich source of new chemical scaffolds for future leishmaniasis treatment as well as for other Neglected Tropical Diseases warranting further investigation.

Viricidal treatments for prevention of coronavirus infection.

Abstract: Coronavirus disease 2019 (COVID-19), which causes severe acute respiratory syndrome and lung failure, is caused by the novel coronavirus, also known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Due to high transmission rates from individual to individual, it has progressed to a pandemic. However, indirect transmission from inanimate objects or surfaces that have come in contact with a patient poses an even more significant threat as it is difficult to trace the source of infection in these cases. Therefore, these surfaces and objects require disinfection with chemicals having potent viricidal activity. These include alcohols, aldehydes, quaternary ammonium compounds, chlorhexidine, and chlorine-based disinfectants, among others. They vary in their viricidal activity depending on their structure, concentrations, and mechanism of action. Several studies have looked into these agents and the transmission of the virus related to it. Moreover, certain viricides, if used as constituents of commercially available oral disinfectants, can further aid in preventing ventilator-associated pneumonia and maintain oral hygiene. However, these chemicals are not entirely free of potential hazards. In this review, we have compiled and critically appraised some commonly used viricidal agents in healthcare settings and the role they can play in the prevention of SARS-CoV-2 transmission.

Prevalence of fluoroquinolone-resistant Salmonella serotypes in Iran: a meta-analysis.

Abstract: The present study was conducted to investigate the antimicrobial susceptibility profiles of Salmonella serotypes, especially fluoroquinolone-resistant strains, recovered from clinical samples in Iran. A full electronic search using related keywords was conducted in Persian and English languages in ISI Web of Knowledge, PubMed, Scopus, Google Scholar and the Scientific Information Database (SID) search engines to find papers published between 1983 and 1 July 2019. According to the inclusion and exclusion criteria, 46 eligible articles were selected for the final analysis out of the initial 13,186 studies retrieved. The pooled prevalence of quinolone-resistant Salmonella serotypes in clinical specimens in Iran was 2.9% to ciprofloxacin and 48.1% to nalidixic acid. Additional data on antibiotic resistance was as follows: 54.3% to tetracycline, 50.6% to ceftizoxime, 50.2% to streptomycin, 37.9% to ampicillin, 36.5% to kanamycin, 33.5% to trimethoprim-sulfamethoxazole, 27.2% to chloramphenicol, 19.1% to cephalothin, 8.8% to ceftriaxone, 7.6% to cefotaxime, 7.4% to aztreonam, 7.2% to gentamicin, 7% to cefepime, 6.8% to ceftazidime, 5.8% to cefixime, 2.7% to imipenem and 2.2% to meropenem. Findings of the present study showed a rising trend of resistance to the drugs of choice for the treatment of Salmonella infections, i.e. ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole in Iran. However, ciprofloxacin, third-generation cephalosporins and carbapenems are still effective antibiotics especially against multi-drug resistant strains in Iran.

Expression levels of candidate circulating microRNAs in pediatric tuberculosis.

Abstract: Tuberculosis (TB) is a preventable and curable disease, but increased mortality and morbidity associated with TB is one of the leading causes of deaths worldwide. MicroRNAs (miRNAs) are small, non-...

Curcuma longa ethanol extract and Curcumin inhibit the growth of Acanthamoeba triangularis trophozoites and cysts isolated from water reservoirs at Walailak University, Thailand.

Abstract: (C. longa) rhizome extract has been traditionally used to treat many infections. Curcumin, a pure compound isolated from the plant, has been documented to possess a wide spectrum of pharmacological...

Immunodominant regions prediction of nucleocapsid protein for SARS-CoV-2 early diagnosis: a bioinformatics and immunoinformatics study.

Abstract: COVID-19 caused by SARS-CoV-2 is sweeping the world and posing serious health problems. Rapid and accurate detection along with timely isolation is the key to control the epidemic. Nucleic acid test and antibody-detection have been applied in the diagnosis of COVID-19, while both have their limitations. Comparatively, direct detection of viral antigens in clinical specimens is highly valuable for the early diagnosis of SARS-CoV-2. The nucleocapsid (N) protein is one of the predominantly expressed proteins with high immunogenicity during the early stages of infection. Here, we applied multiple bioinformatics servers to forecast the potential immunodominant regions derived from the N protein of SARS-CoV-2. Since the high homology of N protein between SARS-CoV-2 and SARS-CoV, we attempted to leverage existing SARS-CoV immunological studies to develop SARS-CoV-2 diagnostic antibodies. Finally, N229-269, N349-399, and N405-419 were predicted to be the potential immunodominant regions, which contain both predicted linear B-cell epitopes and murine MHC class II binding epitopes. These three regions exhibited good surface accessibility and hydrophilicity. All were forecasted to be non-allergen and non-toxic. The final construct was built based on the bioinformatics analysis, which could help to develop an antigen-capture system for the early diagnosis of SARS-CoV-2.

COVID-19 and civil war in Libya: the current situation.

Abstract: A novel coronavirus was reported in December 2019 as the cause of pneumonia in Wuhan, a city in China’s Hubei Province. It spread exponentially, leading to an outbreak throughout China, followed by...

Ebola crisis in Eastern Democratic Republic of Congo: student-led community engagement.

Abstract: The second largest outbreak of Ebolavirus is currently ongoing in Eastern Democratic Republic of the Congo (DRC) and is characterized by lack of compliance with recommended control measures. Truste...

Recommendation of fecal specimen for routine molecular detection of SARS-CoV-2 and for COVID-19 discharge criteria.

Abstract: SARS-CoV-2 causing COVID-19 is now affecting 210 countries and territories around the world, since it first emerged in China [1]. While the death rate is increasing with time, the world is still grappling to develop a vaccine or specific treatments for SARS-CoV-2. So, WHO emphasized diagnosis for each infected case, including asymptomatic cases (which so far represent 30% of total COVID-19 cases) in order for targeted interventions against viral transmission [1]. Despite the false-negative results, RT-PCR assay is considered the standard of reference for diagnosing COVID-19 among the available molecular and serological tests or Chest CT [1,2]. While a higher sensitivity of 97% has been reported for Chest CT compared to RTPCR (71%, p <.001), Chest CT fails to detect the asymptomatic, and even 20% of symptomatic cases, as well as its failure to distinguish radiological changes caused by pathogens other than SARS-CoV-2 [2]. The combination of RT-PCR and Chest CT can be used routinely because of higher sensitivity (91.9%, 79/86) than RTPCR alone (78.2%, 68/87) or CT alone (66.7%, 54 of 81) [2]. However, different studies on RT-PCR showed varied sensitivity depending on the specimens used, which were lung wash (93%), sputum (72%), nasal swabs (63%), lung biopsy (46%), throat swabs (32%), feces (29%), and blood (1%) [1]. This variation is probably due to the increase of viral load in the respiratory specimens from week 1 to week 2 after the onset of illness, which then dropped to lower levels at week 3 and week 4 [3]. But interestingly, the viral load in stool gradually increases after 2–3 weeks causing fecal shedding of viruses during the recovery phase [3]. Thus, fecal samples show positive results in RT-PCR for a longer period compared to respiratory specimens. So, using respiratory tract (RT) samples as the recommended specimen for COVID-19 testing poses an inevitable risk of failure of the containment strategy due to false-negative results, especially in the case of convalescent patients [1]. This is because consecutive two or three negative RT-PCR results for the respiratory specimen are used as the discharge criteria of COVID19 along with subsided clinical symptoms. So, researchers at Chinese University of Hong Kong suggested testing stools as an alternative specimen to deep throat saliva (https://www.med.cuhk.edu.hk/ press-releases/cuhk-finds-that-the-coronavirus-canpersist-in-stool-after-its-clearance-in-respiratory-tractwill-conduct-stool-test-for-people-in-quarantinecamps-for-early-identification). Besides, a study by Tang et al. (2020) [4] reported that an asymptomatic child was found SARS-CoV-2 positive by RT-PCR using stool specimen but negative for RT samples, even after 17 days since the last exposure to SARS-CoV-2. Similarly, eight children infected with SARS-CoV-2 in China, without any specific symptoms or chest X-ray abnormalities continuously showed positive results on rectal swabs by real-time RT-PCR but negative using nasopharyngeal specimens [5]. So, for diagnosing symptomatic patients, especially during the later period of illness or asymptomatic infection, fecal samples could be a better option than the used reference specimen of RT. Detection of SARS-CoV-2 using the appropriate specimen is conducive to regulate the genesis of infection and to confine the progression of the illness. Therefore, the fecal specimen is highly recommended for routine detection of SARS-CoV-2 and especially before discharging COVID-19 patients.

Late incidence of SARS-CoV-2 infection in a highly-endemic remote rural village. A prospective population-based cohort study.

Abstract: Data on SARS-CoV-2 transmission in rural communities is scarce or non-existent. A previous cross-sectional study in middle-aged and older adults enrolled in the Atahualpa Project Cohort demonstrated that 45% of participants had SARS-CoV-2 antibodies, 77% of whom were symptomatic. Here, we assessed the incidence of SARS-CoV-2 infection in the above-mentioned rural population. One month after baseline testing, 362 of 370 initially seronegative individuals were re-tested to assess incidence of seroconversion and associated risk factors. Twenty-eight of them (7.7%) became seropositive. The overall incidence rate ratio was 7.4 per 100 person months of potential virus exposure (95% C.I.: 4.7-10.2). Six seroconverted individuals (21.4%) developed SARS-CoV-2-related symptomatology. The only covariate significantly associated with seroconversion was the use of an open latrine. Predictive margins showed that these individuals were 2.5 times more likely to be infected (95% C.I.: 1.03-6.1) than those using a flushing toilet. Therefore, along one month, approximately 8% of seronegative individuals became infected, even after almost half of the population was already seropositive. Nevertheless, a smaller proportion of incident cases were symptomatic (21% versus 77% of the earlier cases), and no deaths were recorded. Whether this decreased clinical expression resulted from a lower viral load in new infections cannot be determined. Increased seroconversion in individuals using latrines is consistent with a contributory role of fecal-oral transmission, although we cannot rule out the possibility that latrines are acting as a proxy for poverty or other unknown interacting variables.

A review of mechanistic models of viral dynamics in bat reservoirs for zoonotic disease

Abstract: The emergence of SARS-CoV-2, a coronavirus with suspected bat origins, highlights a critical need for heightened understanding of the mechanisms by which bats maintain potentially zoonotic viruses at the population level and transmit these pathogens across species. We review mechanistic models, which test hypotheses of the transmission dynamics that underpin viral maintenance in bat systems. A search of the literature identified only twenty-five mechanistic models of bat-virus systems published to date, derived from twenty-three original studies. Most models focused on rabies and related lyssaviruses (eleven), followed by Ebola-like filoviruses (seven), Hendra and Nipah-like henipaviruses (five), and coronaviruses (two). The vast majority of studies has modelled bat virus transmission dynamics at the population level, though a few nested within-host models of viral pathogenesis in population-level frameworks, and one study focused on purely within-host dynamics. Population-level studies described bat virus systems from every continent but Antarctica, though most were concentrated in North America and Africa; indeed, only one simulation model with no associated data was derived from an Asian bat-virus system. In fact, of the twenty-five models identified, only ten population-level models were fitted to data - emphasizing an overall dearth of empirically derived epidemiological inference in bat virus systems. Within the data fitted subset, the vast majority of models were fitted to serological data only, highlighting extensive uncertainty in our understanding of the transmission status of a wild bat. Here, we discuss similarities and differences in the approach and findings of previously published bat virus models and make recommendations for improvement in future work.

Overlapping of locust swarms with COVID-19 pandemic: a cascading disaster for Africa.

Abstract: The current world is in crisis with the continuing COVID-19 pandemic that has affected 215 countries and territories globally, infecting more than 11 million and causing the death of over half a mi...

A novel Ehrlichia strain (Rickettsiales: Anaplasmataceae) detected in Amblyomma triste (Acari: Ixodidae), a tick species of public health importance in the Southern Cone of America.

Abstract: The aim of this work was to report the detection of a putative novel Ehrlichia strain associated with the tick Amblyomma triste. Free-living adult ticks determined as A. triste were collected by drag-sampling in Argentina and Uruguay. Molecular detection of Ehrlichia agents was performed targeting three different loci: 16S rRNA gene, dsb gene and a fragment of groESL heat shock operon. In total, 164 adults of A. triste (38 from INTA E.E.A Delta del Parana in Argentina and 126 from Toledo Chico in Uruguay) were analyzed. One tick (0.6%) collected in INTA E.E.A. Delta del Parana (Argentina) was positive. The phylogenetic analyses show that the Ehrlichia strain found in this study (named Ehrlichia sp. strain Delta) represents an independent lineage within the genus Ehrlichia, close to E. chaffeensis and E. muris. This is also the first report of an Ehrlichia agent infecting the tick A. triste. The medical and veterinary significance of Ehrlichia sp. strain Delta remains to be demonstrated. However, it is important to mention that adults of A. triste are aggressive to humans and domestic mammals. Therefore, the potential role of A. triste in the transmission of Ehrlichia agents to humans or domestic animals across its distributional range should be highlighted, even more considering that Ehrlichia sp. strain Delta is phylogenetically related to the zoonotic E. chaffeensis, which is recognized as pathogenic to both humans and animals.

Can lactoferrin boost human immunity against COVID-19?

Abstract: COVID-19 caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) belonging to the family Coronaviridae [1] has become a pandemic disease that emerged in China in late 2019 and has si...

Epidemiology of tungiasis in sub-saharan Africa: a systematic review and meta-analysis

Abstract: Tungiasis is a public health disease in many rural and urban slums in sub-Saharan Africa (SSA), primarily affecting children and the elderly. Yet, this disease has received little attention in many...

Identification of bloodmeal sources of triatomines captured in the Paraguayan Chaco region of South America by means of molecular biology analysis

Abstract: The Paraguayan Chaco is an isolated environment with its own unique ecosystem. In this region, Chagas disease remains a health problem. Chagas disease is caused by the parasite Trypanosoma cruzi, and it is primarily transmitted by triatomines. In order to identify the blood meal sources of triatomines, specimens of the vector were collected in domestic and peridomestic areas and the PCR-RFLP method was implemented. Cytochrome b was amplified from the samples and later subjected to digestion with two restriction enzymes: Hae III and Xho I.It was possible to generate distinct restriction patterns on the amplified material to identify several blood meal sources for the vectors. We employed the blood from several species as positive controls: human, chicken, canine, feline, and armadillo blood. However, we identified only 3 sources for the blood meals of the insect vectors: human, chicken and canine blood. In total, 76 triatomines were captured. T. cruzi was not found in any of them. In 61% of the captured specimens, the blood meal sources for the vectors could be identified. In 30% of these cases, the presence of DNA from more than one vertebrate was detected in the same triatomine. The most common blood meal source found was chicken blood. The presence of human and chicken blood in triatomines captured in domestic and peridomestic areas strongly suggests that the parasite can freely move amongst both areas regardless of food availability. Free vector movement in these areas constitutes an epidemiological threat for the inhabitants of the community under study.

Fish-borne trematode infections in wild fishes in Bangladesh.

Abstract: Fish-borne liver and intestinal flukes are helminth pathogens that have a negative impact on public health worldwide. We herein investigated the status of infection by the metacercariae (MC) of fis...

Public health concerns over gene-drive mosquitoes: will future use of gene-drive snails for schistosomiasis control gain increased level of community acceptance?

Abstract: With the advent of CRISPR (clustered regularly interspaced short palindromic repeat)-based gene drive, present genetic research in schistosomiasis vector control envisages the breeding and release of transgenic schistosome-resistant (TSR) snail vectors to curb the spread of the disease. Although this approach is still in its infancy, studies focussing on production of genetically modified (GM) mosquitoes (including gene-drive mosquitoes) are well advanced and set the pace for other transgenic vector research. Unfortunately, as with other GM mosquitoes, open field release of gene-drive mosquitoes is currently challenged in part by some concerns such as gene drive failure and increased transmission potential for other mosquito-borne diseases among others, which might have adverse effects on human well-being. Therefore, not only should we learn from the GM mosquito protocols, frameworks and guidelines but also appraise the applicability of its current hurdles to other transgenic vector systems, such as the TSR snail approach. Placing these issues in a coherent comparative perspective, I argue that although the use of TSR snails may face similar technical, democratic and diplomatic challenges, some of the concerns over gene-drive mosquitoes may not apply to gene-drive snails, proposing a theory that community consent will be no harder and possibly easier to obtain for TSR snails than the experience with GM mosquitoes. In the future, these observations may help public health practitioners and policy makers in effective communication with communities on issues regarding the use of TSR snails to interrupt schistosomiasis transmission, especially in sub-Saharan Africa.

Toxoplasma gondii infection and risk of attention-deficit hyperactivity disorder: a systematic review and meta-analysis

Abstract: Toxoplasma gondii (T. gondii), as an opportunistic neurotropic parasite of the Apicomplexa family, was firstly described in 1908. As attention-deficit hyperactivity disorder (ADHD) is one of the most common neuropsychiatric disorders in children and adolescents and often persists into adulthood, the purpose of this systematic review and meta-analysis was to investigate the relationship between T. gondii infection and ADHD.The data were systematically collected from seven electronic databases up to May 1st 2019 with no language restriction. This study was registered at the International Prospective Register of Systematic Reviews (PROSPERO; code: CRD42020149353). Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using a random effects model. Seven studies involving five cross-sectional and two case-control studies were included in this meta-analysis.Results indicated that there was a statistically non-significant association between exposure to T. gondii infection and increased risk of ADHD based on the detection of immunoglobulin G (IgG) antibody (2.02 [95% CI: 0.97-4.20]; I2=58.7%). However, obtained results of Egger's tests for anti-T. gondii IgG antibody showed publication bias (P=0.014).Sensitivity analysis revealed stable results for the association between anti-T. gondii IgG antibody with ADHD.Given the small number of studies in this field and the obtained results, it cannot be conclusively stated that T. gondii is a risk factor for ADHD.It is important to have reliable information about the relationship between T. gondii and ADHD around the world; as it may lead to better insight to elucidate the possible association of toxoplasmosis and the pathogenesis of ADHD.

Cellular mechanisms regulating synthetic sex ratio distortion in the Anopheles gambiae germline.

Abstract: Genetic control strategies aimed to bias the sex of progenies towards males present a promising new paradigm to eliminate malaria-transmitting mosquitoes. A synthetic sex-ratio distortion (SD) system was successfully engineered in Anopheles gambiae by exploiting the meiotic activity of the I-PpoI endonuclease targeting ribosomal DNA (rDNA) repeats, exclusively located on the X chromosome. Males carrying the SD construct produce highly male-biased progenies without evident reduction in fertility. In this study, we investigated the fate of X and Y chromosomes in these SD males and found that ratios of mature X:Y-bearing sperm were comparable to wild-type insects, indicating absence of selection mechanisms during sperm maturation. We therefore tested the effect of meiotic cleavage of both X and Y chromosomes in a lab-generated SD strain carrying rDNA on both sex chromosomes, showing fertility comparable to wild-type and a reduced male-bias compared to SD males in which only the X is targeted. Exposure of Y-linked rDNA to I-PpoI cleavage for consecutive generations rapidly restored the male-bias to typical high frequencies, indicating a correlation between the number of cleavable targets in each sex chromosome and the sex-ratios found in the progeny. Altogether our results indicate that meiotic cleavage of rDNA repeats, located in the sex chromosomes of A. gambiae SD males, affects the competitiveness of mature sperm to fertilize the female oocyte, thereby generating sex-biased progenies. We also show that the presence of rDNA copies on the Y chromosome does not impair the effectiveness of engineered synthetic SD systems for the control of human malaria mosquitoes.

Prevalence Pattern of Chikungunya Virus Infection in Nigeria: A Four Decade Systematic Review and Meta-analysis

Abstract: Chikungunya (CHIK) is a re-emerging and myo-arthritogenic arboviral infection that has affected significant global population. However, CHIK is a neglected disease in Nigeria. This study aimed to e...