In this paper we introduce a classical SI model to capture the spread of an infectious disease within a population. More precisely, the spatial diffusion of HIV/AIDS in a population is modeled. For that, we assume tha...In this paper we introduce a classical SI model to capture the spread of an infectious disease within a population. More precisely, the spatial diffusion of HIV/AIDS in a population is modeled. For that, we assume that the spread is due to the anarchical comportment of infected individuals along a road, especially, “lorry drivers”. The question which consists of the control of the infection is also addressed. Infected individuals moving from a town to another one, the diffusion is then anisotropic with a main direction of propagation, namely the road direction. Using a semi-group argument and a maximum principle, the uniqueness of a solution to the problem is established. This solution is also estimated. We end this paper by considering some numerical experiments in the case of HIV/AIDS spread in Mali along a road connecting two towns.展开更多
In the last decades several epidemic emergencies have been affecting the world,influencing the social relationships,the economics and the habits.In particular,starting in the early 080,the Acquired Immunodeficiency Sy...In the last decades several epidemic emergencies have been affecting the world,influencing the social relationships,the economics and the habits.In particular,starting in the early 080,the Acquired Immunodeficiency Syndrome,AIDS,is representing one of the most worrying sanitary emergency,that has caused up to now more than 25 million of dead patients.The infection is caused by the Human Immunodeficiency Virus,HIV,that may be transmitted by body fluids;therefore with wise behaviours the epidemic spread could rapidly be contained.This sanitary emergency is peculiar for the long incubation time:it can reach even 10 years,a long period in which the individual can unconsciously infect other subjects.The identification of the number of infected unaware people,mandatory to define suitable containment measures,is here obtained by using the extended Kalman filter applied to a noisy model in which,reasonably,only the number of infected diagnosed patients is available.Numerical simulations and real data analysis support the effectiveness of the approach.展开更多
Background:Contact tracing is one of the strategies used to control COVID-19 pandemic.It played an important role in the beginning to identify all contacts and minimise the spread of the infection.Methods:A retrospect...Background:Contact tracing is one of the strategies used to control COVID-19 pandemic.It played an important role in the beginning to identify all contacts and minimise the spread of the infection.Methods:A retrospective chart review was carried out of contact tracing records during the one-month period,starting from the onset of the first lockdown in India.The largest wave of 372 contacts was analysed in detail to find out the association between the result of COVID-19 test and various factors(age,gender,type of contact).Results:A total of 372 contacts(214 males and 158 females)were traced and around 21%contacts were tested positive on COVID-19 RT-PCR test.Chi-square test didn’t find the significant difference between COVID-19 test result and proportions of male and female contacts,X^(2)(1)0.033,p=0.855.Female positive contacts had lower mean age compared to male positive contacts,though not statistically significant,t(75)=-1.809,p=0.0745.No difference was found in either median or mean age of contacts with respect to COVID-19 test result.Odds of tested COVID-19 positive among household contacts much higher than community contacts,OR=24.52,95%CI 12.45e48.29,p<0.05.Conclusion:No difference was noted in the rate of contracting infection with respect to age and gender of contacts.Type of contact,household or community,significantly affected the probability of becoming infected with the coronavirus.Occupation of primary case was probably responsible for large number of contacts found positive for COVID-19.展开更多
文摘In this paper we introduce a classical SI model to capture the spread of an infectious disease within a population. More precisely, the spatial diffusion of HIV/AIDS in a population is modeled. For that, we assume that the spread is due to the anarchical comportment of infected individuals along a road, especially, “lorry drivers”. The question which consists of the control of the infection is also addressed. Infected individuals moving from a town to another one, the diffusion is then anisotropic with a main direction of propagation, namely the road direction. Using a semi-group argument and a maximum principle, the uniqueness of a solution to the problem is established. This solution is also estimated. We end this paper by considering some numerical experiments in the case of HIV/AIDS spread in Mali along a road connecting two towns.
文摘In the last decades several epidemic emergencies have been affecting the world,influencing the social relationships,the economics and the habits.In particular,starting in the early 080,the Acquired Immunodeficiency Syndrome,AIDS,is representing one of the most worrying sanitary emergency,that has caused up to now more than 25 million of dead patients.The infection is caused by the Human Immunodeficiency Virus,HIV,that may be transmitted by body fluids;therefore with wise behaviours the epidemic spread could rapidly be contained.This sanitary emergency is peculiar for the long incubation time:it can reach even 10 years,a long period in which the individual can unconsciously infect other subjects.The identification of the number of infected unaware people,mandatory to define suitable containment measures,is here obtained by using the extended Kalman filter applied to a noisy model in which,reasonably,only the number of infected diagnosed patients is available.Numerical simulations and real data analysis support the effectiveness of the approach.
文摘Background:Contact tracing is one of the strategies used to control COVID-19 pandemic.It played an important role in the beginning to identify all contacts and minimise the spread of the infection.Methods:A retrospective chart review was carried out of contact tracing records during the one-month period,starting from the onset of the first lockdown in India.The largest wave of 372 contacts was analysed in detail to find out the association between the result of COVID-19 test and various factors(age,gender,type of contact).Results:A total of 372 contacts(214 males and 158 females)were traced and around 21%contacts were tested positive on COVID-19 RT-PCR test.Chi-square test didn’t find the significant difference between COVID-19 test result and proportions of male and female contacts,X^(2)(1)0.033,p=0.855.Female positive contacts had lower mean age compared to male positive contacts,though not statistically significant,t(75)=-1.809,p=0.0745.No difference was found in either median or mean age of contacts with respect to COVID-19 test result.Odds of tested COVID-19 positive among household contacts much higher than community contacts,OR=24.52,95%CI 12.45e48.29,p<0.05.Conclusion:No difference was noted in the rate of contracting infection with respect to age and gender of contacts.Type of contact,household or community,significantly affected the probability of becoming infected with the coronavirus.Occupation of primary case was probably responsible for large number of contacts found positive for COVID-19.
