Epidemiology, Disease Transmission, Prevention, and Control
Julius P. Kreier in Infection, Resistance, and Immunity, 2022
Any deviation of the health status of an individual, human, or animal from normal may be considered a disease. Those diseases that occur at a usual, continuous, persistent low level in a human or animal population in a given geographical area are called endemic or enzootic diseases, respectively. A sudden increase in the number of cases of a disease above its expected incidence is called an epidemic, or an epizootic if in an animal population. Epizootiology is the name sometimes used to describe patterns of disease spread in nonhuman animal populations. A gradual increase in the occurrence of a disease beyond the endemic level, but still not of epidemic proportion is called hyperendemic. When an epidemic affects an extremely high number of individuals distributed worldwide, it is called a pandemic. A similar situation occurring in an animal population is called a panzootic.
The biology of parasites from the genus Argulus and a review of the interactions with its host
G. F. Wiegertjes, G. Flik in Host-Parasite Interactions, 2004
Argulus spp. rarely have significant impacts upon natural fish populations. Epizootics are typically observed when the natural equilibrium is perturbed by one or more factors and in many cases anthropogenic actions have been implicated. For example, increased population densities in fish farms and even commercial sport fisheries facilitate parasite transmission and stress resulting from crowding, capture, handling and confinement can have a deleterious effect upon the fish’s immune response. Menezes et al., (1990) provided evidence that stocking water bodies with non-native fish species can also provide easy targets for lice and as we have seen with Argulus japonicus, anthropogenic transfer of fish can also facilitate parasite dispersal (Rushton-Mellor, 1992).
Arthropod-borne virus encephalitis
Avindra Nath, Joseph R. Berger in Clinical Neurovirology, 2020
Arboviruses are agents of location, season, particular ecologic conditions, and epizootics. These factors are of considerable benefit to the clinician in narrowing the diagnostic possibilities in evaluating cases of encephalitis. In some instances, such as La Crosse virus encephalitis in the U.S. or Central European tick-borne encephalitis, the diseases are endemic and recur with seasonal regularity in particular regions. In other instances, the diseases may appear at varying intervals in epidemic proportions. However, clues are found in the locations of the outbreaks such as epidemics caused by Venezuelan equine encephalitis virus originating in the Guajira Peninsula shared by northern Columbia and Venezuela. The association with epizootics is diagnostically useful. The equine encephalitides spring to mind as do the vulnerability of domestic livestock to Rift Valley fever virus, and crows to West Nile virus in the United States. Heavy rains and flooding or an intense tropical rainy season are the necessary ecological precedents for vector proliferation for many arbovirus agents including Murray Valley encephalitis or Japanese encephalitis viruses.
Broad-spectrum coronavirus antiviral drug discovery
Published in Expert Opinion on Drug Discovery, 2019
Allison L. Totura, Sina Bavari
Highly pathogenic coronaviruses SARS-CoV and MERS-CoV recently emerged into human populations, but other human coronaviruses (HCoVs) including HCoV-OC43, HCoV-229E, HCoV-NL63, and HCoV-HKU1 are estimated to have circulated in human populations for hundreds of years, causing mild respiratory illness to which approximately 5–30% of ‘common colds’ are attributed [7,8]. Within the Coronaviridae family (order Nidovirales) four genera are recognized: alphacoronavirus, betacoronavirus, gammacoronavirus, and deltacoronavirus. The six HCoVs (Table 1) currently identified belong to the genera alphacoronavirus (HCoV-229E and HCoV-NL63) and betacoronavirus (SARS-CoV, MERS-CoV, HCoV-OC43, and HCoV-HKU1). Gammacoronaviruses and deltacoronaviruses have no known viruses that infect humans, but contain important agricultural pathogens of livestock. Epizootic coronaviruses in animals cause a wide range of disease signs resulting from respiratory, enteric, and neurological tissue tropism. Although HCoVs cause primarily respiratory symptoms, the potential for a wide range of severe disease symptoms in humans caused by infection by future emergent coronaviruses cannot be excluded. Despite the severity and diversity of coronavirus disease signs and symptoms affecting a large number of important livestock species as well as humans, there are no proven therapies that specifically target CoVs.
Sub-lethal effects of thiamethoxam on Apis mellifera Linnaeus
Published in Toxin Reviews, 2022
Amit Choudhary, Bharathi Mohindru, Ashok Kumar Karedla, Jaspal Singh, Pardeep K. Chhuneja
Honey bees are social insects and man is hiving bees for a long time. Like other animals, there are certain problems with this organism too which sometimes cause heavy mortality. A record of such incidences has been published by Underwood and vanEngelsdorp (2020). The following is the summary of such a few events occurring in various parts of the world. In the United States of America, the first documented record of mass honey bee colony loss was published during the year 1869 in which bee hives were reported to have plenty of food stores but were devoid of bees. In Australia, Beuhne (1910) recorded acute bee mortality. At the start of the 20th century, i.e. 1906, beekeepers of the United Kingdom observed mortality in honey bee colonies which, based on origin, it was termed as Isle of Wight disease (Bullamore 1922). Similarly, the acute death of honey bee colonies had occurred in Canada during 1917 (Carr 1918), France during 1999–200 (Faucon et al.2002), Germany and Sweden during 2002–03 (Svensson 2003). There are several causes behind such epizootics like abnormal weather conditions, poor nectar flow, reduced immunity due to multiple factors, microorganisms causing various diseases, parasites, pesticides, etc. Among these, the last one is very important, because several cases are linked with direct pesticide poisoning. As we are more concerned with neonicotinoids so we will focus on this group in particular.
Monkeypox re-emergence in Africa: a call to expand the concept and practice of One Health
Published in Expert Review of Anti-infective Therapy, 2019
Mary G. Reynolds, Jeffry B. Doty, Andrea M. McCollum, Victoria A. Olson, Yoshinori Nakazawa
Multi-sectoral disease prevention strategies have gained visibility and traction through various global health initiatives, such as the Global Health Security Agenda [68], often falling under the egis of ‘One Health’ [69]. Conceptually, the goal of One Health is to improve overall health outcomes by recognizing that human and animal health are interdependent and integrally tied to ecosystems. In practice, a key objective of One Health has often been to improve both high-level and on-the-ground coordination and communication between human and veterinary public health services [70,71]. The idea that this latter approach will yield major benefits for wildlife-associated zoonoses can seem counterintuitive, as it is difficult to envision a role for veterinary public health services with diseases such as MPX, which are largely cryptic in nature and do not generate discernable epizootics with large die-offs of animals. In such instances, veterinary services may be of less direct relevance than ecologic science.
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