scholarly journals Mathematical Modelling and Analysis of Transmission Dynamics of Lassa Fever

2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
E. A. Bakare ◽  
E. B. Are ◽  
O. E. Abolarin ◽  
S. A. Osanyinlusi ◽  
Benitho Ngwu ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Numerical Simulations ◽  
Disease Transmission ◽  
Control Program ◽  
Lassa Fever ◽  
Intervention Strategies ◽  
Sub Saharan Africa ◽  
Transmission Dynamics ◽  
Qualitative Properties ◽  
Yearly Average

Sub-Saharan Africa harbours the majority of the burden of Lassa fever. Clinical diseases, as well as high seroprevalence, have been documented in Nigeria, Sierra Leone, Liberia, Guinea, Ivory Coast, Ghana, Senegal, Upper Volta, Gambia, and Mali. Deaths from Lassa fever occur all year round but naturally peak during the dry season. Annually, the number of people infected is estimated at 100,000 to 300,000, with approximately 5,000 deaths. There have been some work done on the dynamics of Lassa fever disease transmission, but to the best of our knowledge, none has been able to capture the seasonal variation of Mastomys rodent population and its impact on the transmission dynamics. In this work, a periodically forced seasonal nonautonomous system of a nonlinear ordinary differential equation is developed that captures the dynamics of Lassa fever transmission and seasonal variation in the birth of Mastomys rodents where time was measured in days to capture seasonality. It was shown that the model is epidemiologically meaningful and mathematically well posed by using the results from the qualitative properties of the solution of the model. A time-dependent basic reproduction number RLt is obtained such that its yearly average is written as R˜L<1, when the disease does not invade the population (means that the number of infected humans always decreases in the seasons of transmission), and R˜L>1, when the disease remains constantly and is invading the population, and it was detected that R˜L≠RL. We also performed some evaluation of the Lassa fever disease intervention strategies using the elasticity of the equilibrial prevalence in order to predict the optimal intervention strategies that can be useful in guiding the local national control program on Lassa fever disease to make a proper decision on the intervention packages. Numerical simulations were carried out to illustrate the analytical results, and we found that the numerical simulations of the model showed that possible combined intervention strategies would reduce the spread of the disease. It was established that, to eliminate Lassa fever disease, treatments with ribavirin must be provided early to reduce mortality and other preventive measures like an educational campaign, community hygiene, isolation of infected humans, and culling/destruction of rodents must be applied to also reduce the morbidity of the disease. Finally, the obtained results gave a primary framework for planning and designing cost-effective strategies for good interventions in eliminating Lassa fever.

scholarly journals Mathematical Modelling for the Transmission Dynamics of blinding Trachoma

2021 ◽  
Author(s):  
Salisu Muhammad Muhammad ◽  
Evren Hincal
Keyword(s):  
Disease Transmission ◽  
Control Program ◽  
Least Square ◽  
Transmission Dynamics ◽  
Reproductive Number ◽  
Model Parameters ◽  
Contact Rate ◽  
Asymptotically Stable ◽  
Vector Transmission ◽  
Disease Vector

Trachsummaroma is an eye infectious disease caused by Chlamydia Trachomatis bacterium, which may lead to irreversible blindness. The disease is spread directly or indirectly by contacting a contaminated material. It can also be transmitted through the disease vector known as “Musca sorbens” or “Bazaar fly”. To curtail the spread of the disease in a population, a meaningful information on the spread and possible control of the disease is required. Mathematical modeling provides efficient tools that can be used to understand and analyze the dynamics of the disease and its control. Several compartmental epidemic models have been proposed in the literature to study the dynamics of trachoma; including SI, SIR and SEIR. However, majority of the existing trachoma models consider only person to person transmission. Thus, the information provided by such models is insufficient since they did not capture the disease vector transmission. The current study proposed a novel SEIR-SEI model that consider both person-person and vector transmission dynamics. The threshold quantity, basic reproduction number R0 is obtained using the next generation matrix, and it was proved that the disease-free equilibrium is asymptotically stable when R0 &lt; 1, and the endemic equilibrium is globally asymptotically stable when R0 &gt; 1. Some simulation results with the aid of mesh plots for the reproductive number as a function of two different biological parameters were obtained. Furthermore, a comprehensive sensitivity analysis is conducted to identify the influence of the individual parameters on the R0. Numerical results show that the vector contact rate has the highest sensitivity with respect to R0, and the value of R0 increases with increase in, hence, the disease can be controlled by decreasing the vector contact rate. Similarly, improving the rate of environmental hygiene and facial cleanliness will decrease the size of R0 and result in the declination of the disease transmission. Moreover, a detailed parameter estimation of the model parameters and model fitting was presented with the use of field data cases from Northern Nigeria using least-square fitting method. The study provides alternative tools that can be used for planning trachoma control program to achieve global eradication of trachoma as a public heath challenge as targeted by WHO in 2030.

scholarly journals A Mathematical Model For Lassa Fever Transmission Dynamics With Impacts of Control Measures: Analysis And Simulation

2021 ◽  
Vol 2 (2) ◽  
pp. 19-28
Author(s):  
Oke Isaiah Idisi ◽  
Tunde Tajudeen Yusuf
Keyword(s):  
Disease Transmission ◽  
Control Strategies ◽  
Disease Outbreaks ◽  
Lassa Fever ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Effective Control ◽  
Lassa Virus ◽  
Long Run ◽  
Globally Stable

Lassa Fever, caused by Lassa virus, is a vector-host transmitted infectious disease whose prevalence has been on the upsurge over the past few decades. Thus, considering the grave implications of the continuous spread of the disease, an epidemic model was developed to describe the disease transmission dynamics with impacts of proposed control measures. This is to help inform effective control strategies that would successfully curtail and contain the disease in its endemic areas. The model is qualitatively analyzed in order to contextualize the long run behavior of the model while the model associated basic reproduction number $(\mathcal{R}_0)$ is derived. The model analysis reveals that the disease-free equilibrium is locally and globally stable whenever $ \mathcal{R}_0 < 1 $ and the disease prevalence would be high as long as $ \mathcal{R}_0 > 1 $. Finally, the model is numerically solved and simulated for different scenarios of the disease outbreaks while the findings from simulations are discussed.

Simulating disease transmission dynamics at a multi-scale level

2007 ◽  
Vol 1 (1) ◽  
pp. 26-34 ◽  
Author(s):  
Moshe B Hoshen ◽  
Anthony H Burton ◽  
Themis J V Bowcock
Keyword(s):  
Disease Transmission ◽  
Transmission Dynamics ◽  
Scale Level ◽  
Multi Scale

Interactions between ecological and socio-economic drivers of Buruli ulcer burden in Sub-Saharan Africa: opportunities for an improved control

2018 ◽  
Author(s):  
Andes Garchitorena ◽  
Matthew H. Bonds ◽  
Jean-Francois Guégan ◽  
Benjamin Roche
Keyword(s):  
Socioeconomic Factors ◽  
Disease Transmission ◽  
Access To Health Care ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Sub Saharan Africa ◽  
Aquatic Environments ◽  
Human Populations ◽  
Complex Interactions ◽  
Sub Saharan

This chapter provides an overview of the complex interactions between ecological and socioeconomic factors for the development and control of Buruli ulcer in Sub-Saharan Africa. We review key ecological and evolutionary processes driving the environmental persistence and proliferation of Mycobacterium ulcerans, the causative agent, within aquatic environments, as well as transmission processes from these aquatic environments to human populations. We also outline key socioeconomic factors driving the economic and health burden of Buruli ulcer in endemic regions, revealed by reciprocal feedbacks between poverty, disease transmission from exposure aquatic environments and disease progression to severe stages owing to low access to health care. The implications of such insights for disease control, both in terms of limitations of current strategies and directions for the future, are discussed.

scholarly journals Volterra–Lyapunov Stability Analysis of the Solutions of Babesiosis Disease Model

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1272
Author(s):  
Fengsheng Chien ◽  
Stanford Shateyi
Keyword(s):  
Mathematical Model ◽  
Stability Analysis ◽  
Global Stability ◽  
Numerical Simulations ◽  
Lyapunov Stability ◽  
Disease Model ◽  
Transmission Dynamics ◽  
Global Stability Analysis ◽  
Lyapunov Stability Analysis ◽  
Disease Free

This paper studies the global stability analysis of a mathematical model on Babesiosis transmission dynamics on bovines and ticks populations as proposed by Dang et al. First, the global stability analysis of disease-free equilibrium (DFE) is presented. Furthermore, using the properties of Volterra–Lyapunov matrices, we show that it is possible to prove the global stability of the endemic equilibrium. The property of symmetry in the structure of Volterra–Lyapunov matrices plays an important role in achieving this goal. Furthermore, numerical simulations are used to verify the result presented.

scholarly journals Control trial of porcine cysticercosis in Uganda using a combination of the TSOL18 vaccination and oxfendazole

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Zachary Nsadha ◽  
Chris Rutebarika ◽  
Chrisostom Ayebazibwe ◽  
Bukenya Aloys ◽  
M. Mwanja ◽  
...  
Keyword(s):  
Taenia Solium ◽  
Control Program ◽  
Control Area ◽  
Sub Saharan Africa ◽  
Intermediate Hosts ◽  
Porcine Cysticercosis ◽  
Intervention Area ◽  
Significant Difference ◽  
Sub Saharan ◽  
Village Communities

Abstract Background Neurocysticercosis caused by Taenia solium when the parasite lodges in the central nervous system, is an important cause of human seizures and mortality in sub-Saharan Africa. The parasite is prevalent in many regions of Uganda. Pigs are intermediate hosts for T. solium, and we evaluated a T. solium control program in pigs, involving vaccination of pigs with the TSOL18 vaccine and treatment with oxfendazole. Methods The study was conducted in two districts of Eastern Uganda involving the rural village communities of Bukedea (intervention area) and Kumi (control area) during 2016–2017. Seven hundred and thirty-four households were enrolled in the study. Pigs in the intervention area received intramuscular immunizations with TSOL18 (Cysvax™) and an oral medication with 30 mg/kg oxfendazole (Paranthic™) at approximately 3-monthly intervals for 18 months. Porcine cysticercosis was evaluated by post-mortem examination. At the beginning of the study, 111 pigs were examined. In an interim evaluation in the intervention area, 55 pigs were evaluated 12 months after starting the project. At the end of the study approximately 3 months after the final intervention, 55 pigs from the intervention area and 56 pigs from the control area were evaluated. Results The prevalence of porcine cysticercosis for the two sites was 16.2% at the beginning of the study (17.2% in the intervention area and 15.1% in the control area) with no statistically significant difference (P = 0.759) between the two study sites. Among the 110 animals assessed from the intervention site (55 at the interim evaluation and 55 at the final evaluation), no pig with viable T. solium cysts was found. There was a statistically significant difference between the prevalence at baseline (17.2%) and at the end of the study (0%) in the intervention area (P = 0.001) and a statistically significant difference between the intervention (0%) and control areas (5.4%) (P = 0.041) at the end of the study. Conclusions Three-monthly concurrent vaccination of pigs with the TSOL18 vaccine and medication with oxfendazole eliminated T. solium transmission by the animals involved in the study. Application of vaccination with medication in pigs has the potential to reduce transmission of T. solium in Uganda and other endemic countries.

scholarly journals Genomic analysis of group B Streptococcus from milk demonstrates the need for improved biosecurity: a cross-sectional study of pastoralist camels in Kenya

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dinah Seligsohn ◽  
Chiara Crestani ◽  
Taya L. Forde ◽  
Erika Chenais ◽  
Ruth N. Zadoks
Keyword(s):  
Public Health ◽  
Milk Production ◽  
Disease Transmission ◽  
Tetracycline Resistance ◽  
Genomic Analysis ◽  
Sub Saharan Africa ◽  
Camel Milk ◽  
Interspecies Transmission ◽  
Cross Sectional ◽  
Group B

Abstract Background Streptococcus agalactiae (Group B Streptococcus, (GBS)) is the leading cause of mastitis (inflammation of the mammary gland) among dairy camels in Sub-Saharan Africa, with negative implications for milk production and quality and animal welfare. Camel milk is often consumed raw and presence of GBS in milk may pose a public health threat. Little is known about the population structure or virulence factors of camel GBS. We investigated the molecular epidemiology of camel GBS and its implications for mastitis control and public health. Results Using whole genome sequencing, we analysed 65 camel milk GBS isolates from 19 herds in Isiolo, Kenya. Six sequence types (STs) were identified, mostly belonging to previously described camel-specific STs. One isolate belonged to ST1, a predominantly human-associated lineage, possibly as a result of interspecies transmission. Most (54/65) isolates belonged to ST616, indicative of contagious transmission. Phylogenetic analysis of GBS core genomes showed similar levels of heterogeneity within- and between herds, suggesting ongoing between-herd transmission. The lactose operon, a marker of GBS adaptation to the mammary niche, was found in 75 % of the isolates, and tetracycline resistance gene tet(M) in all but two isolates. Only the ST1 isolate harboured virulence genes scpB and lmb, which are associated with human host adaptation. Conclusions GBS in milk from Kenyan camel herds largely belongs to ST616 and shows signatures of adaptation to the udder. The finding of similar levels of within- and between herd heterogeneity of GBS in camel herds, as well as potential human-camel transmission highlights the need for improved internal as well as external biosecurity to curb disease transmission and increase milk production.

scholarly journals Mathematical model of COVID-19 intervention scenarios for São Paulo—Brazil

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Osmar Pinto Neto ◽  
Deanna M. Kennedy ◽  
José Clark Reis ◽  
Yiyu Wang ◽  
Ana Carolina Brisola Brizzi ◽  
...  
Keyword(s):  
Compartmental Model ◽  
Time Window ◽  
Algorithm Design ◽  
Sao Paulo ◽  
Intervention Strategies ◽  
Transmission Dynamics ◽  
São Paulo ◽  
Protective Behavior ◽  
Social Distancing ◽  
Multi Objective Genetic Algorithm

AbstractWith COVID-19 surging across the world, understanding the effectiveness of intervention strategies on transmission dynamics is of primary global health importance. Here, we develop and analyze an epidemiological compartmental model using multi-objective genetic algorithm design optimization to compare scenarios related to strategy type, the extent of social distancing, time window, and personal protection levels on the transmission dynamics of COVID-19 in São Paulo, Brazil. The results indicate that the optimal strategy for São Paulo is to reduce social distancing over time with a stepping-down reduction in the magnitude of social distancing every 80-days. Our results also indicate that the ability to reduce social distancing depends on a 5–10% increase in the current percentage of people strictly following protective guidelines, highlighting the importance of protective behavior in controlling the pandemic. Our framework can be extended to model transmission dynamics for other countries, regions, states, cities, and organizations.

scholarly journals The effects of flooding and weather conditions on leptospirosis transmission in Thailand

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sudarat Chadsuthi ◽  
Karine Chalvet-Monfray ◽  
Anuwat Wiratsudakul ◽  
Charin Modchang
Keyword(s):  
Sensitivity Analysis ◽  
Public Education ◽  
Mathematical Models ◽  
Disease Transmission ◽  
Transmission Rate ◽  
Weather Conditions ◽  
Transmission Dynamics ◽  
Multiplication Rate ◽  
High Degree ◽  
Transmission Models

AbstractThe epidemic of leptospirosis in humans occurs annually in Thailand. In this study, we have developed mathematical models to investigate transmission dynamics between humans, animals, and a contaminated environment. We compared different leptospire transmission models involving flooding and weather conditions, shedding and multiplication rate in a contaminated environment. We found that the model in which the transmission rate depends on both flooding and temperature, best-fits the reported human data on leptospirosis in Thailand. Our results indicate that flooding strongly contributes to disease transmission, where a high degree of flooding leads to a higher number of infected individuals. Sensitivity analysis showed that the transmission rate of leptospires from a contaminated environment was the most important parameter for the total number of human cases. Our results suggest that public education should target people who work in contaminated environments to prevent Leptospira infections.

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