Project description:We have published a paper showing that infections using mosquito-transmitted parasites have a quite different effect on the host immune system (Spence et al, Nature, 2013). Here we are repeating the experiment but using a more virulent strain of the parasite: P. chabaudi CB, to study further how mosquito transmission regulates parasite virulence. This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/
Project description:Use of the bacterium Wolbachia is an innovative new strategy designed to break the cycle of dengue transmission. There are two main mechanisms by which Wolbachia could achieve this: by reducing the level of dengue virus in the mosquito and/or by shortening the host mosquito's lifespan. However, although Wolbachia shortens the lifespan, it also gives a breeding advantage which results in complex population dynamics. This study focuses on the development of a mathematical model to quantify the effect on human dengue cases of introducing Wolbachia into the mosquito population. The model consists of a compartment-based system of first-order differential equations; seasonal forcing in the mosquito population is introduced through the adult mosquito death rate. The analysis focuses on a single dengue outbreak typical of a region with a strong seasonally-varying mosquito population. We found that a significant reduction in human dengue cases can be obtained provided that Wolbachia-carrying mosquitoes persist when competing with mosquitoes without Wolbachia. Furthermore, using the Wolbachia strain WMel reduces the mosquito lifespan by at most 10% and allows them to persist in competition with non-Wolbachia-carrying mosquitoes. Mosquitoes carrying the WMelPop strain, however, are not likely to persist as it reduces the mosquito lifespan by up to 50%. When all other effects of Wolbachia on the mosquito physiology are ignored, cytoplasmic incompatibility alone results in a reduction in the number of human dengue cases. A sensitivity analysis of the parameters in the model shows that the transmission probability, the biting rate and the average adult mosquito death rate are the most important parameters for the outcome of the cumulative proportion of human individuals infected with dengue.
Project description:This is a coupled multiscale mathematical model of malaria control and elimination containing four submodels: mosquito-to-human transmission of the malaria parasite, human-to-mosquito transmission of the malaria parasite, a within-mosquito malaria parasite population dynamics sub-model and a within-human malaria parasite population dynamics sub-model.
Model is encoded by Johannes and submitted to BioModels by Ahmad Zyoud.
Project description:Filarial nematodes are arthropod-borne nematodes that cause a variety of economically important diseases such as onchocerciasis (river blindness), lymphatic filariasis, and heartworm disease. The most widespread filarial disease of humans is lymphatic filariasis, caused by worms in the genera Wuchereria and Brugia. Lymphatic filariasis is an economic and social burden in endemic countries and affects approximately 119 million people worldwide (Michael, 1997). In humans, the worms live in and block the lymph vessels, causing improper flow of lymph, and inflammation of the lymphatic system. The symptoms are fever, swollen limbs and genitals, generalized malaise, and can progress to a debilitating condition known as elephantiasis This research focuses on the transmission of these worms to the disseminating mosquito host, and it is based on the interesting observation that mf must be at least 7 days old to successfully infect the mosquito (de Hollanda, 1982). Newborn mf that have not âmaturedâ cannot successfully penetrate the midgut of the mosquito, and subsequently cannot develop to the L3 stage (Fuhrman, 1987). Previous work done by another group 20 years ago suggests that the molecular makeup of the worm surface changes during this maturation process (Furman, 1983 a and b). We used microarray analysis to characterize changes in gene expression that take place during the mf maturation process. Understanding the gene expression changes that occur as the mf mature will allow us to understand the nature of the philological transition that allows mf to move from the human to the mosquito host. With this information in hand, we can eventually identify parasite molecules that could be targeted to either stop parasite reproduction or prevent transmission of the mf to the mosquito. This would stop parasite transmission in endemic areas. Two biological replicates were performed each with two technical replicates.
Project description:To investigate the potential vertical transmission of chronic stress to the unexposed larvae, to report novel consequences of paternally inherited chronic stress at molecular level
Project description:The impact of global climate change on the transmission dynamics of infectious diseases is the subject of extensive debate. The transmission of mosquito-borne viral diseases is particularly complex, with climatic variables directly affecting many parameters associated with the prevalence of disease vectors. While evidence shows that warmer temperatures often decrease the extrinsic incubation period of an arthropod-borne virus (arbovirus), exposure to cooler temperatures often predisposes disease vector mosquitoes to higher infection rates. RNA interference pathways are essential to antiviral immunity in the mosquito; however, few experiments have explored the effects of temperature on the RNAi machinery.
Project description:Filarial nematodes are arthropod-borne nematodes that cause a variety of economically important diseases such as onchocerciasis (river blindness), lymphatic filariasis, and heartworm disease. The most widespread filarial disease of humans is lymphatic filariasis, caused by worms in the genera Wuchereria and Brugia. Lymphatic filariasis is an economic and social burden in endemic countries and affects approximately 119 million people worldwide (Michael, 1997). In humans, the worms live in and block the lymph vessels, causing improper flow of lymph, and inflammation of the lymphatic system. The symptoms are fever, swollen limbs and genitals, generalized malaise, and can progress to a debilitating condition known as elephantiasis This research focuses on the transmission of these worms to the disseminating mosquito host, and it is based on the interesting observation that mf must be at least 7 days old to successfully infect the mosquito (de Hollanda, 1982). Newborn mf that have not â??maturedâ?? cannot successfully penetrate the midgut of the mosquito, and subsequently cannot develop to the L3 stage (Fuhrman, 1987). Previous work done by another group 20 years ago suggests that the molecular makeup of the worm surface changes during this maturation process (Furman, 1983 a and b). We used microarray analysis to characterize changes in gene expression that take place during the mf maturation process. Understanding the gene expression changes that occur as the mf mature will allow us to understand the nature of the philological transition that allows mf to move from the human to the mosquito host. With this information in hand, we can eventually identify parasite molecules that could be targeted to either stop parasite reproduction or prevent transmission of the mf to the mosquito. This would stop parasite transmission in endemic areas. Brugia pahangi mature mf (30 days and older) RNA was compared to immature mf (3 days and younger). Three biological replicates were performed each with two technical replicates