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Introduction to Cells, DNA, and Viruses
Published in Patricia G. Melloy, Viruses and Society, 2023
A few key terms are associated with describing a disease caused by a pathogen that has taken hold in a community. For example, if a pathogen were creating disease at low but consistent levels in a geographic area, the disease would be called endemic. If there is a sudden increase in the number of cases of a disease, and the disease begins to spread in new ways, the disease would be called an epidemic. Finally, a disease that becomes prevalent worldwide is known as a pandemic (Minkoff and Baker 2004f). Pathogens also typically have some kind of vector contributing to the spread of the disease to humans. The vector is a living thing, like an animal, interacting with humans while remaining unimpacted by the disease. I consider it like the “bagman” for the virus. The abundance of the vector itself is affected by one of the key characteristics affecting the spread of a pathogen—weather and environment as well as travel and trade.
Challenges of Global Healthcare Disasters
Published in Adarsh Garg, D. P. Goyal, Global Healthcare Disasters, 2023
Deepika Sherawat, Sonia, Priyanka Shukla
An epidemic is a disease that affects a large number of people within a community, population, or region, and a pandemic is an epidemic that is spread over multiple countries and continents. Pandemics and large-scale epidemics that can claim loss of lives of masses, disrupt civilizations, and shatter economies. WHO’s Health Emergencies Programme (WHE) is working with member states to help countries to prepare for large-scale outbreaks and pandemics. Countries are also encouraged to involve the whole of society for effective pandemic preparedness and response. The pandemics are new and highly infectious airborne viruses that have an impact on the population that lack immunity. Some of the most infectious viruses that have infected masses are influenza. Some of the diseases are spread by blood-feeding anthropoids like mosquitoes, fleas, and ticks. Such diseases are called vector-borne diseases. The vector-borne diseases are Nile virus, dengue fever, malaria, Zika, and chikungunya to name a few. Most of these diseases are fanned by climate change.
The Challenge of Parasite Control
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Control of vector-borne diseases is also possible through modifications of the environment such as draining water bodies, altering irrigation practices and managing vegetation. Other relatively simple techniques, including vector trapping (Box 9.1) and the improvement of sub-standard housing can negatively affect vectors and thereby reduce their populations. In recent years, however, environmental manipulation for vector control has been largely relegated to the back burner. In schistosomiasis control programs, for example, transmission control of any kind has been largely replaced by morbidity control through chemotherapy. Regarding malaria, as discussed above, vector control efforts focus almost entirely on the use of insecticides. Manipulations that make habitats less suitable for Anopheles mosquitoes are frequently the fortuitous consequence of economic development or improved housing. The story is similar for other vector-borne parasitic diseases.
Visceral leishmaniasis elimination in India: progress and the road ahead
Published in Expert Review of Anti-infective Therapy, 2022
Om Prakash Singh, Shyam Sundar
The World Health Organization-supported visceral leishmaniasis (VL) elimination initiative in India does not aim at zero transmission of L. donovani, but at ‘reducing the VL incidence rates in the region below levels of public health concern’ [43]. These were empirically defined as an incidence rate below 1 per 10,000 population per year at sub-district or block PHCs level. Key components of the strategy are the prompt diagnosis and treatment of clinical VL and vector control by systematic indoor residual spraying (IRS) [26]. Vector control is an important tool in bringing down the transmission of the disease. Earlier, insecticides like DDT and deltamethrin were used for vector management, but these were not very effective. Alpha cypermethrin is now being used in control program. However, supply of spray equipments and availability of man power are still major issue and needs to be improved.
Detection of Neoehrlichia mikurensis DNA in blood donors in southeastern Sweden
Published in Infectious Diseases, 2022
Lisa Labbé Sandelin, Jenny Olofsson, Conny Tolf, Louise Rohlén, Lars Brudin, Ivar Tjernberg, Per-Eric Lindgren, Björn Olsen, Jonas Waldenström
Although vector-borne infectious agents can be found in blood, they are generally not transmitted directly by blood contact, but by a vector, such as a tick or a mosquito [20]. As a result, vector-borne infections vary geographically depending on vector species distribution, competency, and available reservoirs [8,21]. Several tick-borne pathogens can potentially be transmitted through blood transfusion. Furthermore, many tick-borne microorganisms are located intracellularly, which is an excellent condition for transmission by transfusion [21]. Different tick-borne infections have different cell tropisms that affect prevalence and density in human blood, and thus the probability of transfusion-mediated transmission [22]. In the Northern Hemisphere, a limited number of tick-borne infections have been identified as TTIs [21,22]. The intraerythrocytic protozoan Babesia spp. is of greatest concern to recipient safety [1]. Of transfusion-transmitted tick-borne rickettsiae, Anaplasma phagocytophilum, which infects granulocytes and causes anaplasmosis, is most frequently reported [8,23].
The race for a COVID-19 vaccine: where are we up to?
Published in Expert Review of Vaccines, 2022
Md Kamal Hossain, Majid Hassanzadeganroudsari, Jack Feehan, Vasso Apostolopoulos
Viral vectors are a biological technology that has been used in science and medicine since the 1970s. Very recently, this platform has been used to control the Ebola outbreaks. In this technology, the genetic material (DNA) of a viral vector vaccine is carried within a harmless adenovirus, adeno-associated virus, retrovirus, and lentivirus [64]. Vaccine development using this platform has been widely explored. The genome of one virus is used to deliver the antigen of another virus in this platform. This platform has been validated for large-scale commercial production. However, it has some limitations, such as a significant variation in purification methods, leading to inaccurate purity and activity of the vaccines. This platform has been explored for a number of vaccines such as Ebola, Marburg virus, influenza, Chikungunya, Zika, Lassa mammarena virus, Human/Simian immunodeficiency virus, cancers, and many more [65–67]. Currently, approximately 59 candidates using this platform are under investigation for a COVID-19 vaccine. However, viral vectors may trigger the risk factors, including genotoxic events, e.g. inflammation, random insertion disrupting normal genes, activation of proto-oncogenes, and insertional mutagenesis [68].