scholarly journals Asymmetric percolation drives a double transition in sexual contact networks

2017 ◽  
Vol 114 (34) ◽  
pp. 8969-8973 ◽  
Author(s):  
Antoine Allard ◽  
Benjamin M. Althouse ◽  
Samuel V. Scarpino ◽  
Laurent Hébert-Dufresne
Keyword(s):  
Analytical Description ◽  
Sexual Contact ◽  
Transmission Dynamics ◽  
Random Networks ◽  
Mosquito Vector ◽  
Percolation Process ◽  
Contact Networks ◽  
Double Transition ◽  
Sexual Contacts ◽  
Males And Females

Zika virus (ZIKV) exhibits unique transmission dynamics in that it is concurrently spread by a mosquito vector and through sexual contact. Due to the highly asymmetric durations of infectiousness between males and females—it is estimated that males are infectious for periods up to 10 times longer than females—we show that this sexual component of ZIKV transmission behaves akin to an asymmetric percolation process on the network of sexual contacts. We exactly solve the properties of this asymmetric percolation on random sexual contact networks and show that this process exhibits two epidemic transitions corresponding to a core–periphery structure. This structure is not present in the underlying contact networks, which are not distinguishable from random networks, and emerges because of the asymmetric percolation. We provide an exact analytical description of this double transition and discuss the implications of our results in the context of ZIKV epidemics. Most importantly, our study suggests a bias in our current ZIKV surveillance, because the community most at risk is also one of the least likely to get tested.

scholarly journals Double asymmetric percolation drives a quadruple transition in sexual contact networks

2019 ◽  
Author(s):  
Hongyu Zheng ◽  
Xiangrui Zeng
Keyword(s):  
Sexual Contact ◽  
Graph Structure ◽  
Mosquito Vectors ◽  
Percolation Process ◽  
Contact Networks ◽  
Scale Free ◽  
Scale Free Networks ◽  
Control And Prevention ◽  
Asymmetric Factor ◽  
Insight Into

AbstractSince 2007, ZIKV outbreaks have been occurring around the world. While ZIKV is mainly spread by mosquito vectors, transmission via sex activities enables the virus to spread in regions without mosquito vectors. Modeling the patterns of ZIKV outbreak in these regions remain challenging. We consider age as an asymmetric factor in transmitting ZIKV, in addition to gender as seen in previous literature, and modify the graph structure for better modeling of such patterns. We derived our results by both solving the underlying differential equations and simulation on population graph. Based on a double asymmetric percolation process on sexual contact networks. we discovered a quadruple ZIKV epidemic transition. Moreover, we explored the double asymmetric percolation on scale-free networks. Our work provides more insight into the ZIKV transmission dynamics through sexual contact networks, which may potentially provide better public health control and prevention means in a ZIKV outbreak.

scholarly journals Assessment of Overlap of Phylogenetic Transmission Clusters and Communities in Simple Sexual Contact Networks: Applications to HIV-1

PLoS ONE ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. e0148459 ◽  
Author(s):  
Luc Villandre ◽  
David A. Stephens ◽  
Aurelie Labbe ◽  
Huldrych F. Günthard ◽  
Roger Kouyos ◽  
...  
Keyword(s):  
Sexual Contact ◽  
Contact Networks ◽  
Hiv 1

A two-stage percolation process in random networks

2015 ◽  
Author(s):  
Xiao Jia ◽  
Jin-Song Hong ◽  
Chun Yang ◽  
Chuan-Ji Fu ◽  
Jian-Quan Hu
Keyword(s):  
Random Networks ◽  
Two Stage ◽  
Percolation Process

scholarly journals Phylodynamics on local sexual contact networks

2017 ◽  
Vol 13 (3) ◽  
pp. e1005448 ◽  
Author(s):  
David A. Rasmussen ◽  
Roger Kouyos ◽  
Huldrych F. Günthard ◽  
Tanja Stadler
Keyword(s):  
Sexual Contact ◽  
Contact Networks

scholarly journals Analysis of the Model on the Effect of Seasonal Factors on Malaria Transmission Dynamics

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Victor Yiga ◽  
Hasifa Nampala ◽  
Julius Tumwiine
Keyword(s):  
Malaria Transmission ◽  
Basic Reproduction Number ◽  
Deterministic Model ◽  
Reproduction Number ◽  
Equilibrium Points ◽  
Current Control ◽  
Transmission Dynamics ◽  
Mosquito Vector ◽  
The Impact ◽  
The Basic Reproduction Number

Malaria is one of the world’s most prevalent epidemics. Current control and eradication efforts are being frustrated by rapid changes in climatic factors such as temperature and rainfall. This study is aimed at assessing the impact of temperature and rainfall abundance on the intensity of malaria transmission. A human host-mosquito vector deterministic model which incorporates temperature and rainfall dependent parameters is formulated. The model is analysed for steady states and their stability. The basic reproduction number is obtained using the next-generation method. It was established that the mosquito population depends on a threshold value θ , defined as the number of mosquitoes produced by a female Anopheles mosquito throughout its lifetime, which is governed by temperature and rainfall. The conditions for the stability of the equilibrium points are investigated, and it is shown that there exists a unique endemic equilibrium which is locally and globally asymptotically stable whenever the basic reproduction number exceeds unity. Numerical simulations show that both temperature and rainfall affect the transmission dynamics of malaria; however, temperature has more influence.

scholarly journals Transmission of Human Papillomavirus Without Sexual Contact

2016 ◽  
Vol 6 (1) ◽  
pp. 8-12
Author(s):  
Panteha Tavassol ◽  
Naweed Ahmed ◽  
Wakqas Kayani ◽  
Sahab Jamshidi ◽  
Suneil Bapat ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
South Asian ◽  
Viral Infections ◽  
Genital Warts ◽  
Sexual Contact ◽  
Early Age ◽  
Sexually Transmitted ◽  
Physical Environments ◽  
History Of ◽  
Males And Females

Human papillomavirus (HPV) is one of the most common sexually transmitted infections. There are four common HPV strains: 6, 11, 16, and 18. Strains 6 and 11 cause genital warts, while strains 16 and 18 are asymptomatic in males and may progress to cervical cancer in females. Although uncommon, a small percentage of males and females have been diagnosed with HPV without previous sexual contact. In this case report, we discuss a case conducted on a 15-year-old South Asian male who contracted an unknown low-risk strain of HPV with no history of sexual contact. HPV is highly infectious, however in the majority of cases the immune system is able to clear the infection, preventing the appearance of genital warts. In cases such as these, it is important to help control the spread of viral infections. Several determinants of health are involved in and affect the transmission of HPV, including income and social status, social support networks, education and literacy, culture, social and physical environments, and health services. To aid in the prevention of HPV, sexual education should be taught at early ages within schools and the Gardasil® vaccine should be administered to both females and males at an early age to reduce the burden of disease and the incidence of HPV.

Child Molestation and Homosexuality

1986 ◽  
Vol 58 (1) ◽  
pp. 327-337 ◽  
Author(s):  
Paul Cameron ◽  
Kay Proctor ◽  
William Coburn ◽  
Nels Forde ◽  
Helen Larson ◽  
...  
Keyword(s):  
Los Angeles ◽  
Generational Differences ◽  
Sexual Contact ◽  
Washington Dc ◽  
Child Molestation ◽  
Sexual Involvement ◽  
Sexual Molestation ◽  
Sexual Contacts ◽  
Random Probability ◽  
Sex With Men

How much child molestation occurs in our society and how much is homosexual? Random-probability samples in Los Angeles, Denver, Omaha, Louisville, and Washington, DC yielded 4,340 adults who answered an extensive questionnaire regarding sexual attitudes, activities, and experiences. Results indicate that perhaps 16% of both boys and girls claim sexual relations with an adult before the age of 16; if only experiences with men are counted about 5% of boys and 15% of girls claim sexual involvements. Sexual contacts with adults before respondents were aged 13 were claimed by 9% of boys and 7% of girls; if only experiences with men are counted, only 3% of boys claimed molestation. Considering only children's claims of sex with men, about a third were homosexual molestations. About 1% of females claimed some sexual involvement with their fathers and a like number with stepfathers. The latter were considerably more apt to be considered “serious.” About 1% of elementary pupils and 3% of secondary pupils claimed sexual advances by teachers and about a third of these advances resulted in physical sexual contact. Bisexuals or homosexuals claimed much more frequent sexual contact with caretakers, and homosexuality was disproportionately implicated in sexual events under caretakers' charge. No generational differences in rate of claims of sexual molestation were found.

Female-Female Competition and Male Mate Choice in Barbary Macaques (Macaca Sylvanus)

Behaviour ◽  
1996 ◽  
Vol 133 (9-10) ◽  
pp. 763-790 ◽  
Author(s):  
Jutta Kuester ◽  
Andreas Paul
Keyword(s):  
Mate Choice ◽  
Female Competition ◽  
Male Mate Choice ◽  
Reproductive Suppression ◽  
Macaca Sylvanus ◽  
Barbary Macaque ◽  
Sexual Contacts ◽  
Males And Females ◽  
Male Mate ◽  
Reproductive Females

AbstractDue to a strong breeding synchronization, the Barbary macaque is a likely candidate for female competition for access to mates, female reproductive suppression, and male mate choice. The present study evaluated the significance of these factors for the mating system of this species. Female competition was analysed from focal observations of 19 out of 59 potentially reproductive females in their conception period. Ad libitum recorded sexual interactions of all animals were used for an analysis of male mate choice. The focal females were aggressive towards females once per 6.1 h and received aggression from females once per 3.8 h. However, they were three times more frequently the target of male aggression (once per 1.2 h), whereby the aggressor was often the momentary sexual partner. Rate of aggression received from males and females was not related with female rank. Females of all cycle stages disturbed sexual contacts, whereby the intruder was dominant to the target in most episodes (86 out of 100). Intruders more attractive than their targets were most successful in terminating the sexual association of their target, but success of intrusions was low and not related with female rank. The intruder copulated with the former partner of her target in only 5 intrusion episodes. Rate and date of conception and infant survival was not related with female rank, indicating that aggression against females during the conception period and intrusions into sexual contacts did not impair reproduction. Therefore, female

scholarly journals Testing configurations of attractive toxic sugar bait (ATSB) stations in Mali, West Africa, for improving the control of malaria parasite transmission by vector mosquitoes and minimizing their effect on non-target insects

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Rabiatou A. Diarra ◽  
Mohamed M. Traore ◽  
Amy Junnila ◽  
Sekou F. Traore ◽  
Seydou Doumbia ◽  
...  
Keyword(s):  
Feeding Rate ◽  
Uv Light ◽  
Optimal Number ◽  
Mosquito Vector ◽  
Feeding Rates ◽  
Light Traps ◽  
Wide Scale ◽  
Males And Females ◽  
Bait Stations ◽  
The Village

Abstract Background Application methods of |Attractive Toxic Sugar Baits (ATSB) need to be improved for wide-scale use, and effects on non-target organisms (NTOs) must be assessed. The goals of this study were to determine, at the village level, the effect of different configurations of bait stations to (1) achieve < 25% Anopheles mosquito vector daily feeding rate for both males and females and (2) minimize the effect on non-target organisms. Methods Dye was added to Attractive Sugar Bait Stations (without toxin) to mark mosquitoes feeding on the baits, and CDC UV light traps were used to monitor for marked mosquitoes. An array of different traps were used to catch dye marked NTOs, indicating feeding on the ASB. Stations were hung on homes (1, 2, or 3 per home to optimize density) at different heights (1.0 m or 1.8 m above the ground). Eight villages were chosen as for the experiments. Results The use of one ASB station per house did not mark enough mosquitoes. Use of two and three stations per house gave feeding rates above the 25% goal. There was no statistical difference in the percentage of marked mosquitoes between two and three stations, however, the catches using two and three bait stations were both significantly higher than using one. There was no difference in An. gambiae s.l. feeding when stations were hung at 1.0 and 1.8 m. At 1.8 m stations sustained less accidental damage. ASB stations 1.8 m above ground were fed on by three of seven monitored insect orders. The monitored orders were: Hymenoptera, Lepidoptera, Coleoptera, Diptera, Hemiptera, Neuroptera and Orthoptera. Using one or two stations significantly reduced percentage of bait-fed NTOs compared to three stations which had the highest feeding rates. Percentages were as follows: 6.84 ± 2.03% Brachycera followed by wasps (Hymenoptera: Vespidae) 5.32 ± 2.27%, and Rhopalocera 2.22 ± 1.79%. Hanging the optimal number of stations per house for catching mosquitoes (two) at 1.8 m above ground, limited the groups of non-targets to Brachycera, Chironomidae, Noctuoidea, Rhopalocera, parasitic wasps and wasps (Hymenoptera). Feeding at 1.8 m only occurred when stations were damaged. Conclusions The goal of marking quarter of the total Anopheles population per day was obtained using 2 bait stations at 1.8 m height above the ground. This configuration also had minimal effects on non-target insects.

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