Fractional-calculus analysis of the transmission dynamics of the dengue infection.

In this research paper, a novel approach in dengue modeling with the asymptomatic carrier and reinfection via the fractional derivative is suggested to deeply interrogate the comprehensive transmission phenomena of dengue infection. The proposed system of dengue infection is represented in the Liouville-Caputo fractional framework and investigated for basic properties, that is, uniqueness, positivity, and boundedness of the solution. We used the next-generation technique in order to determine the basic reproduction number R0 for the suggested model of dengue infection; moreover, we conduct a sensitivity test of R0 through a partial rank correlation coefficient technique to know the contribution of input factors on the output of R0. We have shown that the infection-free equilibrium of dengue dynamics is globally asymptomatically stable for R0<1 and unstable in other circumstances. The system of dengue infection is then structured in the Atangana-Baleanu framework to represent the dynamics of dengue with the non-singular and non-local kernel. The existence and uniqueness of the solution of the Atangana-Baleanu fractional system are interrogated through fixed-point theory. Finally, we present a novel numerical technique for the solution of our fractional-order system in the Atangana-Baleanu framework. We obtain numerical results for different values of fractional-order ϑ and input factors to highlight the consequences of fractional-order ϑ and input parameters on the system. On the basis of our analysis, we predict the most critical parameters in the system for the elimination of dengue infection.

Power-series solution of compartmental epidemiological models.

In this work, power-series solutions of compartmental epidemiological models are used to provide alternate methods to solve the corresponding systems of nonlinear differential equations. A simple and classical SIR compartmental model is considered to reveal clearly the idea of our approach. Moreover, a SAIRP compartmental model is also analyzed by using the same methodology, previously applied to the COVID-19 pandemic. Numerical experiments are performed to show the accuracy of this approach.

Numerical simulation and stability analysis for the fractional-order dynamics of COVID-19.

The main purpose of this work is to study the dynamics of a fractional-order Covid-19 model. An efficient computational method, which is based on the discretization of the domain and memory principle, is proposed to solve this fractional-order corona model numerically and the stability of the proposed method is also discussed. Efficiency of the proposed method is shown by listing the CPU time. It is shown that this method will work also for long-time behaviour. Numerical results and illustrative graphical simulation are given. The proposed discretization technique involves low computational cost.

Durability, household usage and washing pattern of DuraNet© and Interceptor® long-lasting insecticidal nets in long-term field trials in India.

BACKGROUND & OBJECTIVES: Universal coverage of population with long-lasting insecticidal nets (LLINs) living in endemic areas inhabited by ethnic tribal communities or in difficult to reach areas was found effective for disease control where other interventions such as indoor residual spraying have limited success because of operational issues. Evaluation of different LLINs with varied insecticides and fabrics are being evaluated to meet the demand of new products. This study was undertaken on two brands of LLINs, DuraNet© and Interceptor® that varied in fabric and manufacturing technologies to assess the usability in field conditions for atleast three years. METHODS: In large-scale field trials DuraNet©, alpha cypermethrin incorporated polyethylene net, was evaluated in Odisha state while, Interceptor® net, alpha cypermethrin coated polyester net was evaluated in Chhattisgarh and Gujarat states for a period of three years following WHO guidelines. Durability, usage pattern and washing behavior were monitored through periodic surveys and physical examination of nets. RESULTS: Survivorship of both the nets was 84-100% and every night usage rate was >62% in all seasons. Washing frequency was largely within the prescribed limits. The proportion of DuraNet© with holes was 26.7% in year one 74% in year three. In Gujarat, proportion of Interceptor® nets with holes at six months was 33.3% increased to 87% in year three and in Chhattisgarh, 6.7% after six months to 93.3% after three years of use respectively. INTERPRETATION & CONCLUSION: Both the nets revealed a useful life of three years under the field condition.

Some new and modified fractional analysis of the time-fractional Drinfeld-Sokolov-Wilson system.

In this paper, we present a presumably new approach in order to solve the time-fractional Drinfeld-Sokolov-Wilson system, which is based upon the Liouville-Caputo fractional integral (LCFI), the Caputo-Fabrizio fractional integral, and the Atangana-Baleanu fractional integral in the sense of the LCFI by using the Adomian decomposition method. We compare the approximate solutions with the exact solution (if available), and we find an excellent agreement between them. In the case of a non-integer order, we evaluate the residual error function, thereby showing that the order of the error is very small. In all of our calculations, we apply the software package, Mathematica (Version 9).

Some new mathematical models of the fractional-order system of human immune against IAV infection.

Fractional derivative operators of non-integer order can be utilized as a powerful tool to model nonlinear fractional differential equations. In this paper, we propose numerical solutions for simulating fractional-order derivative operators with the power-law and exponential-law kernels. We construct the numerical schemes with the help the fundamental theorem of fractional calculus and the Lagrange polynomial interpolation. These schemes are applied to simulate the dynamical fractional-order model of the immune response (FMIR) to the uncomplicated influenza A virus (IAV) infection, which focuses on the control of the infection by the innate and adaptive immunity. Numerical results are then presented to show the applicability and efficiency on the FMIR.

An efficient spectral collocation method for the dynamic simulation of the fractional epidemiological model of the Ebola virus.

This article investigates a family of approximate solutions for the fractional model (in the Liouville-Caputo sense) of the Ebola virus via an accurate numerical procedure (Chebyshev spectral collocation method). We reduce the proposed epidemiological model to a system of algebraic equations with the help of the properties of the Chebyshev polynomials of the third kind. Some theorems about the convergence analysis and the existence-uniqueness solution are stated. Finally, some numerical simulations are presented for different values of the fractional-order and the other parameters involved in the coefficients. We also note that we can apply the proposed method to solve other models.

Preface: Recent Advances in Fractional Dynamics.

This Special Focus Issue contains several recent developments and advances on the subject of Fractional Dynamics and its widespread applications in various areas of the mathematical, physical, and engineering sciences.

Weekly versus Three-Weekly Cisplatin-based Concurrent Chemoradiotherapy as definitive treatment in Head and Neck Cancer- Where do we stand?

PURPOSE: To compare toxicity, compliance, and early response of weekly and 3-weekly cisplatin administration concurrent with radiotherapy as definitive treatment in locally advanced squamous cell carcinoma head and neck. MATERIALS AND METHODS: Patients with histologically proven stage III - IV B head and neck carcinoma presenting from June 2013 to March 2014 were randomly assigned to weekly (35 mg/m2, 6 cycles; arm A) and 3 weekly (100 mg/m2, 3 cycles; arm B) cisplatin with concurrent radiotherapy. RESULTS: 60 patients were randomly assigned to treatment, 30 in each arm. Median follow-up was 8 months (range 4-13). There was no significant difference in grade 3 mucositis between the two arms (75.9% vs 70%, p = 0.20). Grade 3 neutropenia was more frequent in arm B (55.2% vs 26.7%, p = 0.01). Hypomagnesemia was the commonest electrolyte imbalance and it was significantly higher in arm B (60% vs 20%, p = 0.001). Completion rate of scheduled chemotherapy cycles was higher for patients receiving weekly regimen. Response at 3 months was similar for all the patients {Complete Response (66.7% vs 62.1%), p = 0.200}. Our data suggested that there is a reduced need of hospitalization and supportive care measures for patients receiving weekly cisplatin with RT (p = 0.05). CONCLUSIONS: Weekly cisplatin 35 mg/m2 chemotherapy concurrent with radiotherapy is equally effective and less toxic in terms of neutropenia, hypomagnesemia and need for supportive measures than the conventional 3 weekly cisplatin 100 mg/m2 regimen.

What is the value of reactive case detection in malaria control? A case-study in India and a systematic review.

BACKGROUND: Reactive case detection (RCD) for malaria is a strategy to identify additional malaria infections in areas of low malaria transmission and can complement passive surveillance. This study describes experiences with RCD in two Indian sites, and aimed to synthesize experiences with RCD across endemic countries. METHODS: RCD programmes were piloted in two urban areas of India with a low prevalence of mainly Plasmodium vivax malaria in 2014. Cases were identified in a clinic by microscopy and contacts were screened within 2 weeks; PCR, in addition to microscopy, was used to detect Plasmodium parasites. A systematic review was conducted to identify RCD experiences in the literature. RESULTS: In Chennai, 868 contacts were enrolled for 18 index cases of clinical malaria; in Nadiad, 131 contacts were enrolled for 20 index cases. No new malaria infections were detected in Nadiad among contacts, and four new infections were detected in Chennai (three P. vivax and one Plasmodium falciparum), of which two were among household members of index cases. An additional five studies describing results from an RCD strategy were identified in the literature: four in Africa and one in Thailand. Including the results from India, the average number of contacts screened per index case in a total of seven studies ranged from four to 50, and 126 in a case study in Thailand with one index case. Malaria was detected in 0-45 % of the contacted persons. The average number of index cases needed to be traced to find one new case of malaria ranged from one to five, and could not be assessed in one study in India (no contacts positive for 20 cases). Sharing the household with an index case was associated with a five-fold increased risk of malaria compared to contacts from households without an index case (pooled risk ratio 5.29, 95 % CI 3.31-8.47, I(2) 0 %, four studies). CONCLUSIONS: RCD in areas of low malaria transmission is a labour-intensive strategy, and its benefit is not clear. Studies are needed to assess how RCD can be optimized or into alternatives where interventions are targeted to family members or hotspots.

Malaria Epidemiology and Control Within the International Centers of Excellence for Malaria Research.

Understanding the epidemiological features and metrics of malaria in endemic populations is a key component to monitoring and quantifying the impact of current and past control efforts to inform future ones. The International Centers of Excellence for Malaria Research (ICEMR) has the opportunity to evaluate the impact of malaria control interventions across endemic regions that differ in the dominant Plasmodium species, mosquito vector species, resistance to antimalarial drugs and human genetic variants thought to confer protection from infection and clinical manifestations of plasmodia infection. ICEMR programs are conducting field studies at multiple sites with the aim of generating standardized surveillance data to improve the understanding of malaria transmission and to monitor and evaluate the impact of interventions to inform malaria control and elimination programs. In addition, these epidemiological studies provide a vast source of biological samples linked to clinical and environmental "meta-data" to support translational studies of interactions between the parasite, human host, and mosquito vector. Importantly, epidemiological studies at the ICEMR field sites are integrated with entomological studies, including the measurement of the entomological inoculation rate, human biting index, and insecticide resistance, as well as studies of parasite genetic diversity and antimalarial drug resistance.

Entomological indicators during transmission season of dengue in Silvassa (India).

The entomological surveillance was conducted in urban, semi-urban/slum, industrial and residential areas during main transmission period from June to November 2012. In residential sites house index was 41.7-35.0, breteau index 71.7-136.7 and container index 11.6-20.2. During transmission period all the values ware much higher than the threshold level. The causes of high values of entomological indicator appeared to be rapid industrialization, unawareness of the conditions or factors that can exacerbate mosquito breeding, water storage habits in community and un-implementation of health related legislation.

Review of the bioenvironmental methods for malaria control with special reference to the use of larvivorous fishes and composite fish culture in central Gujarat, India.

Mosquito control with the use of insecticides is faced with the challenges of insecticide resistance in disease vectors, community refusal, their high cost, operational difficulties, and environmental concern. In view of this, integrated vector control strategies with the use of larvivorous fishes such as Guppy (Poecilia reticulata) and Gambusia (G. affinis) as biological control agents were used in controlling mosquito breeding in different types of breeding places such as intradomestic containers, various types of wells, rice-fields, pools, ponds and elsewhere in malaria prone rural areas of central Gujarat. Attempts were also made to demonstrate composite fish culture in unused abandoned village ponds by culturing Guppy along with the food fishes such as Rohu (Labeo rohita), Catla (Catla catla) and Mrigal (Cirrhinus mrigala). Income generated from these ponds through sale of fishes was utilized for mosquito control and village development. The technology was later adopted by the villagers themselves and food fish culture was practised in 23 ponds which generated an income of Rs 1,02,50,992 between 1985 and 2008. The number of villages increased from 13 to 23 in 2008 and there was also gradual increase of income from Rs 3,66,245 in 1985-90 to Rs 55,06,127 in 2002-08 block. It is concluded that larvivorous fishes can be useful tool in controlling mosquito breeding in certain situations and their use along with composite fish culture may also generate income to make the programme self-sustainable.

Pregnancy concomitant with metastatic adult granulosa cell tumor.

INTRODUCTION: Metastatic adult granulosa cell tumor of the ovary is rarely encountered with pregnancy. CASE REPORT AND RESULTS: Primigravida (26 years) presented at 20 weeks of gestation with acute abdomen and clinical evidence of supraclavicular lymphadenopathy and ascites. She was diagnosed of adult granulosa cell tumor (AGCT) of the right ovary following right salpingoophrectomy done 1 month prior to conception. Fine needle aspiration cytology of supraclavicular lymph node, revealed it to be a metastatic AGCT. Chemotherapy was given antepartum and she delivered a healthy preterm baby at 30 weeks. Subsequently, she had optimal debulking surgery following 6 cycles of cisplatin-based chemotherapy. Baby at 10 months of age was with normal milestones. CONCLUSIONS: The case is an unusual presentation of metastatic adult granulosa cell tumor at child bearing age. Although rapidly progressing, successful prolongation of pregnancy till 30 weeks of gestation was possible with the judicious use of chemotherapy. Fetal and maternal outcomes were favorable.

Evaluation of the pyrrole insecticide chlorfenapyr for the control of Culex quinquefasciatus Say.

Culex quinquefasciatus Say (Diptera: Culicidae) is a widely distributed mosquito vector species in India and also in other tropical regions of the world. This species is implicated in the transmission of lymphatic filariasis in many countries. This species is reported to be widely resistant to insecticides of different classes in current use. In the present study, bio-efficacy of chlorfenapyr, an insecticide of pyrrole class with a novel mode of action was tested for the control of Cx. quinquefasciatus. Studies were performed to determine the diagnostic dosage; residual efficacy on different artificially fabricated substrates, namely wood, mud, mud+lime, cement and cement+distemper; to assess cross-resistance with different insecticides; and synergism/antagonism using piperonyl butoxide (PBO). A dosage of 5.0% chlorfenapyr was determined as diagnostic dosage with 2 h exposure and 48 h holding period for assessing the susceptibility of mosquitoes. The residual efficacy was observed up to 34 weeks on wood and mud+lime substrates while on other substrates, it was about 15 weeks at a dosage of 400mg a.i./m(2). Laboratory-reared strains of Cx. quinquefasciatus showed cross-resistance, whereas field-collected mosquitoes showed absence of cross-resistance to chlorfenapyr. Potentiation bioassays showed antagonistic effect of PBO to chlorfenapyr toxicity owing to the involvement of oxidases in the initial step of a conversion of pro-insecticide chlorfenapyr to toxic form CL 303268. The present study results have shown that chlorfenapyr can be a potential insecticide for the control of multiple insecticide resistant strains of Cx. quinquefasciatus. However, in countries where indoor residual spray (IRS) is not targeted for the control of this species, like in India, chlorfenapyr used in IRS for the control of malaria vectors in rural and peri-urban areas can additionally provide control of Cx. quinquefasciatus also.

Malaria in seasonal migrant population in Southern Gujarat, India.

Malaria in migrant workers is always a major problem to control due to their temporary stay in shelters, and other operational constraints. Hence, a study was undertaken in brick kilns in Bharuch district, Gujarat state, India to study the problem of malaria in the work force. Mass blood surveys were carried out in 15 brick kilns. Blood slides were collected from both febrile and afebrile cases. Positive cases were treated as per the national drug policy and were followed up. Mosquito collections were carried out by pyrethrum spray collection in early morning hours. Human blood index and sporozoite rates were determined as per standard procedures. All age groups were found affected with malaria at brick kilns. Prevalence of malaria was significantly higher in ≤ 14 years of age-group as compared to adults. Post treatment follow up examination of patients revealed high malaria infection due to non-compliance of chloroquine. The appearance of parasitaemia among Plasmodium falciparum treated cases indicate the possibility of chloroquine resistance. The proportion of P. falciparum was >50% in migrant population. In stable population in villages, overall decline in malaria cases was observed in 2008-2010. The sporozoite rate of 4.2% in Anopheles culicifacies indicates active malaria transmission at brick kilns. The investigation demonstrated that suitable microclimatic conditions for malaria transmission exist in these areas during hottest period. The district health department should consider these factors in planning malaria surveillance and control. As current magnitude and diversity of population movements in rural as well as in urban areas are unprecedented, this issue is worthy of attention.

Persistence of DDT, malathion & deltamethrin resistance in Anopheles culicifacies after their sequential withdrawal from indoor residual spraying in Surat district, India.

BACKGROUND & OBJECTIVES: Under the national antimalaria programme DDT was introduced in early 1950s for vector control and later hexachloro cyclohexane (HCH) followed by malathion and recently synthetic pyrethroids in 1990s to manage the insecticide resistance in Anopheles culicifacies. Subsequent replacement led to development of multiple resistances in An. culicifacies in Surat district in Gujarat State. Indoor residual spray (IRS) was completely withdrawn in southern villages in Surat in 2002. This study was undertaken in these areas to study the persistence of resistance to DDT, malathion and deltamethrin after sequential withdrawal of IRS with these insecticides at different times. METHODS: Susceptibility tests on An. culicifacies were conducted using standard WHO methods and kits. Mortality, knockdown time and lethal times were calculated for An. culicifacies exposed to WHO prescribed diagnostic concentrations of different insecticide impregnated papers. RESULTS: Persistence of DDT-resistance was observed even after 30 yr of its withdrawal from IRS. Similarly, persistence of malathion resistance was also observed after 9 yr of its withdrawal from IRS, while reversal of deltamethrin-resistance was observed very fast within 2-3 yr after its withdrawal from IRS in 2002. INTERPRETATION & CONCLUSION: Present data indicate that the quantum of reversion of insecticide resistance in a population is relative and depends on the genetic stability of the respective resistance genes in the mosquitoes. In the present study withdrawal of pyrethroid-IRS resulted in increased susceptibility against pyrethroids alone and was independent of existence of resistance to insecticides of other groups. This study emphasizes that appropriate rotation of different insecticides; including carbamates may prevent or delay the onset of resistance.

Therapeutic responses of Plasmodium vivax and P. falciparum to chloroquine, in an area of western India where P. vivax predominates.

In 2003-2005, following an increase in the local incidence of human malaria, the therapeutic efficacy of chloroquine (CQ) in the treatment of Plasmodium vivax and P. falciparum malaria was evaluated in the Anand district of Gujarat state, in western India. After oral administration of CQ, clinical and parasitological responses were measured over a follow-up period of 28 days, following the standard protocol of the World Health Organization. Most of the recurrent infections were checked, by genotyping, to see whether they were the result of treatment failure or re-infection during the follow-up. At the primary health centre (PHC) in Deva, all 57 P. vivax cases included in the study responded to CQ within 3 days. At the Pansora PHC, however, only 59 [90.8%, with a 95% confidence interval (CI) of 83.7%-97.8%] of the 65 P. vivax cases appeared to respond completely, recurrent infections being observed in the other six cases (9.2%; CI=2.2%-16.3%). Of the four recurrent infections checked by genotyping, however, only two appeared to be the result of true treatment failure. Twenty-seven (81.8%; CI=67.2%-94.4%) of the 33 P. falciparum cases who were enrolled in the study, all from Pansora PHC also showed apparent treatment failure, with one early failure, 17 late clinical failures and nine late parasitological failures. All 23 P. falciparum cases that showed apparent treatment failure and were investigated by genotyping appeared to be true cases of failure, none showing any evidence of re-infection during follow-up. The mean parasite-clearance times for those infected with P. falciparum, both those considered CQ-sensitive and the treatment failures, exceeded 2 days. These results indicate the presence of CQ-resistant P. vivax and P. falciparum in Anand district. The high frequency of CQ failure against P. falciparum observed in this study led to a change in the drug policy at the Pansora PHC, with artemisinin-based combination therapy now being used for the first-line treatment of P. falciparum malaria. Chloroquine remains the recommended first-line treatment for P. vivax infections in the area but the treatment failure seen in at least two P. vivax cases indicates a need for further monitoring of the therapeutic efficacy of CQ against such infections, in central Gujarat and elsewhere.

Pulsed laser deposition of metal films and nanoparticles in vacuum using subnanosecond laser pulses.

A study of silver, chromium, stainless-steel, and indium thin films prepared by subnanosecond laser deposition in vacuum is reported. We compare the laser ablation in vacuum at the weak- and tight-focusing conditions of a Ti:sapphire laser beam and analyze the nanoparticles synthesized in the latter case using absorption spectroscopy, x-ray fluorescence, atomic force microscopy, and scanning electron microscopy. Our results show that the nanoparticle formation can be accomplished using long laser pulses under tight-focusing conditions.