Molecular epidemiology of Foot and Mouth Disease virus (FMD) in Southern Africa.by station k b
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Molecular epidemiology of Foot and Mouth Disease virus (FMD) in Southern Africa.
Foot-and-mouth disease virus (FMDV) is the causative agent of a highly contagious and economically devastating disease of cloven-hooved domestic and wild animals. It can cause a high number of deaths among young animals and production losses in adults and is the single most limiting constraint to international trade of live animals and animal products. It is indeed a contagious viral disease of sheep, cattle, pigs, and wild ruminants. The disease causes a high rate of morbidity in multiple species, and is highly communicable and spreads rapidly once introduced into nonimmune herds. It is defined by the OIE as a category A disease: “Communicable diseases which have potential for serious and rapid spread, irrespective of national borders, which are of serious socioeconomic or public health consequence and which are of major importance in the international trade of livestock and products, FMD virus can be transmitted through a variety of mechanisms including Inhalation or ingestion (from infected source to susceptible animals), Direct contact with infected animals, Mechanical fomites (e.g., vehicles, instruments, feed), Airborne (up to 60 km overland and 300 km by sea) in temperate zones under proper conditions (these include a high viral load [e.g., a swine herd infection], stable atmospheric conditions, and a susceptible population downwind) (Hames and Rickwood, 2004)
The Essay on Hand Foot Mouth Disease
Advise to parent with infected child Page 4 5. 8. Prevention for family members of infected child 5. 9. Treatment plans 5. Conclusion Page 5 6. Reference Page 5 HANDS, FOOT AND MOUTH DISEASE 1. Introduction This report discusses what Hand, Foot and Mouth Disease (HFMD) is how it is spread as well as the precautions one should take to avoid getting HFMD. There have been recurrent outbreaks of HFMD ...
Genetic characterization of SAT type viruses is well documented for the southern African region; emphasis has been on viruses isolated from the African buffalo (Syncerus caffer) and on cattle viruses from West Africa and East Africa .On the basis of nucleotide sequence analysis of a portion of the viral genomes obtained from buffalo and domestic animals in sub-Saharan Africa, 14 independently evolving viral genotypes were identified for SAT 2, 8 for SAT 1, and 6 for SAT 3. FMDV SAT 1 was first isolated in Ethiopia . FMDV belongs to the genus Aphthovirus in the family Picornaviridae and possesses a single strand of positive-sense RNA genome. It has a high mutation rate because the viral RNA–dependent RNA polymerase lacks proofreading ability, resulting in 7 immunogenically distinct serotypes (O, A, C, Southern African Territories [SAT] 1, SAT 2, SAT 3, and Asia 1) and numerous and constantly evolving variants showing a spectrum of antigenic diversity. Vaccination is an effective way to control FMD; however, the protection conferred by vaccination or infection is usually serotype specific and sometimes incomplete within a serotype.
FMDV has a genome consisting of a single strand of positive-sense RNA. Consequently, the virus has a high mutation rate and may change, on a random basis, 1–8 nucleotides (nt) per replication cycle. Nucleotide sequencing of part or all of the genome region coding for the outer capsid polypeptide VP1 was first used to study the epidemiology of FMD by Beck and Strohmaier , who investigated the origin of outbreaks of types O and A in Europe over a 20-year period. Since then, genetic variability has been used to individually characterize strains of FMDV and track their movement across international borders, and a large number of epidemiologic studies have been published. Previously, on the basis of comparisons of partial VP1 sequences (≈170 nt at the 3´ end of the gene) of FMD type O viruses, differences between 2 isolates within 4% have been suggested to indicate a recent common origin, whereas differences of >15% signify geographic isolation over many years, similar to the distinctions made between human polioviruses. Isolates with >85% nt sequence identity have been placed within groups or topotypes, which tend to be restricted in their geographic distribution. The 10 topotypes have been named Europe-South America (Euro-SA), Middle East–South Asia (ME-SA), Southeast Asia (SEA), Cathay (CHY), West Africa (WA), East Africa 1 (EA-1), East Africa 2 (EA-2), East Africa 3 (EA-3), Indonesia-1 (ISA-1), and Indonesia-2 (ISA-2).
The Term Paper on Aids In Africa Hiv Virus People
The AIDS epidemic has reached disastrous proportions on the continent of Africa. Over the past two decades, two thirds of the more than 16 million people in the world infected with Human Immunodeficiency Virus (HIV), which causes AIDS, live in sub-Saharan Africa. It is now home to the largest number of people infected, with 70 percent of the world's HIV infected population. The problem of this ...
The Indonesian topotypes, which have not been identified since 1983, are considered extinct. (Alfred et al, 2002).
FMD is endemic to sub-Saharan Africa; widespread outbreaks of clinical disease occur during most years. Of the 7 serotypes, 6 have reportedly occurred on the African continent, and disease control becomes more complicated because of marked regional differences in the distribution and prevalence of various serotypes and intratypic variants .FMD remains largely uncontrolled in southern Africa because vaccination for prophylactic purpose is not being practiced except for a few dairy herds containing exotic animals. With no control and preventive measures in place, FMD causes substantial economic loss to farmers and to the nation from embargoes of livestock and livestock product trade . To initiate control measures for FMD, the following must be identified: origin of infection, links between outbreaks, extent of genetic variation of the causative viruses, and antigenic relationship of field isolates to the available vaccines. (Hames and Rickwood, 2004)
Phylogenetic analysis of the virus protein (VP) 1 region of FMD viruses has been used extensively to investigate the molecular epidemiology of the disease worldwide. These techniques have helped define genetic relationships between FMDV isolates and geographic distribution of lineages and genotypes; they have also helped establish genetically and geographically linked topotypes and trace the source of outbreaks. Topotypes are defined as geographically clustered viruses that form a single genetic lineage generally sharing >85% (O, A, C, and Asia 1) or >80% (SAT 1, SAT 2, and SAT 3) nucleotide identity in the VP1-coding region. (Smith and Ritchie, 2001),
The Essay on Foot And Mouth Animals Farmers Disease
Problems faced by farmers in the UK In recent years, farmers in the UK have had to cope with many problems, the most recent of these being foot and mouth disease, which is a highly contagious viral illness that afflicts sheep, pigs, cows, goats, deer and other animals with cloven hoofs. Foot-and-mouth can be fatal to animals, but most can recover from the disease. Since its latest outbreak was ...
In southern Africa the cycle between wildlife and domestic animals occurs, while in West Africa, due to the low numbers of wildlife, the disease is maintained predominately in domestic animals. However, once disease crosses from wildlife into domestic animals, a domestic cycle could be maintained without the involvement of wildlife. As it is costly to sample wildlife, very little is known about the FMD virus populations circulating in these animals and most information outside southern Africa is based on isolates obtained from domestic animals. Molecular epidemiological studies have contributed in planning control strategies by elucidating historical and current disease transmission patterns within and between countries. Furthermore, it is important to have data on the viral topotypes in both wildlife and domestic animals, information that should be heeded when planning FMD vaccination strategies (Elles, 2004).
High levels of genetic diversity will most likely be reflected in antigenic differences and it has been shown that for vaccination to be effective, the viruses incorporated into vaccines need to be antigenically related to viruses circulating in the field (Alfred et al, 2002).
Emergence of these viruses will greatly affect spread and consequent control strategy of the disease on this continent because restriction of animal movement between many southern African countries is limited.
References
Alfred G , Raven E.R, Evert.G.J, Eichhorn V.B (2002), A History of Experimental virology, 2nd Ed, Springer-Verlag Company, Inc, USA, Pg 178-204
Elles R (2004), Molecular Diagnosis of Genetic Diseases, 7th Ed, Humana Press, Towawa, New Jersey, Pg 391, 392
Hames B.D and Rickwood D.T, (2004), Virology in animals, 4th Ed, Bios scientific Publishers, USA, Pg 122,143,300
Smith K.M and Ritchie D.A, (2001), Introduction to Virology, 3rd Ed, Chapman and Hall, Inc, New York, Pg 20-21
The Essay on Infectious Disease Virus Malaria Viruses
Introduction to viruses: For centuries submicroscopic organisms, also known as viruses, that grow and multiply at different rates inside of a cell, have been circulating our planet. 1 The cell produces the various, essential components of the virus. These components are: 1) DNA or RNA nucleic acids, which are the genes of the virus. Viral particles posses either DNA strands or RNA strands, but ...
