The Role Of Migratory Birds

The Role Of migrant BirdsThe post of migrant annuluss in transmitting bird affections is becoming a contentious issue in the whole world. The issue has even do researchers and naturalists to differ in opinion regarding their capability to disperse pathogens across continents. late(a) studies that were conducted during the bird flu outbreaks make out that a migrant bird is capable of disseminating the deadly H5N1 avian influenza without themselves getting infect. Research has shown that these birds ar responsible for contagion of many diseases, especially viral, in types of animals. This study so has the mandate to critically analyze how migratory birds back up in transmittal of diseases. The study will alike focus on the discordant types of diseases that be transmissible by these birds.IntroductionBirds be possessed of been cognise since time hoary to be migrating from one region to another. The birds aro intake be local migrants, misfortunate outstrip migrants, long distance migrants and nomadic and vagrant migrants. They do exit across national and international borders. The migration is endlessly due to the reason for survival. This instinct leads birds to look for seasonal opportunities for food supply and action habitats. The findings from the studies conducted on the purpose of bird migration reveal that millions of birds migrate annually from unfavorable to favorable conditions (Hubalek, 1994, 2004). uncomplimentary conditions argon usually in spend while the favorable ar in summer. Birds consequently migrate from places where at that place is winter to places with seasons of winter. This explains why the migration is rampant.The environmental conditions during summer accelerate food accumulation and breeding because of the better climatic conditions. Through biological systems, birds store up energy and fats during this season. The energy and fats stored aid in migration when there be changing survival conditions in the h abitat. During this termination, winter falls. An interesting observation is that not all birds migrate with the changing conditions. The prototype of migration differs with species and requirements (Berthold Peter, 2001). Some birds do migrate over short distance fair(a) to look for food and come back. Others migrate over long distance and may come back or not.The migration of these birds is a natural phenomenon. They have to do that in order to maintain ecological balance and near meaning(a)ly, to survive. However, the natural phenomenon is always fol paltryed by harsh repercussions that are unavoidable. It is saddening to know that these birds are either carriers or hosts for pathogens. As they migrate, these birds transfer micro-organisms across localities, nations and even continents. They therefore play a pregnant role in the ecology and morbific organism circulation. These birds are implicated as hosts and mechanical carriers of infected ecto-parasites. They are in like manner implicated in the transmission of zoonoses. It is not possible to station a stop to this sequence but we can minimize the risks involved. This can be done by controlling and preventing perilous situations.Pathogens contractable by migratory birdsAvian Pneumovirus (APV). This virus belongs to the genus Metapneumovirus. It causes a respiratory disease which is known as turkey rhinotrachetis (TRT). This disease is commonly known as vain head syndrome (SHS) in jaundiceds (Gough, 2003Lwamba et al., 2002). This disease kills municipal birds, especially turkey at a very elevated rate. It has been found out that it only takes a few moments after the attack before the bird dies. When the bird gets a secondary bacteriuml infection and immunosuppressive viral disease, the severity of APV is deepen (Lwamba 2002, Jones 2006).The significance of migratory birds in the epidemiology and persistence of APV in interior(prenominal) wad has been ascertained by means of and throu gh isolation routine (Shin et al., 2000). When isolation of APV from choanal swab or nasal turbinate of unjustifiable birds like geese, sparrows, swallows mallards and starling is done, there is a laid-back persistence of APV concomitant.Bennett (2204) observed a seasonal trend of disease occurrence during APV outbreaks in Minnesota. He suggested the suspected involvement/role of bad migratory birds in APV transmission. When a nucleotide sequencing was done, it was deduced that there was a common germ for the APV isolates extracted from wild ducks, domestic turkeys and geese. It was also deduced that the viruses from the different species can cross-infect. This indicated a closelipped relationship (Shin et al., 2002).Duck plague virus (DPV)This is a highly catching disease of Anseriformes. The duck plague/ viral enteritis causes high mortality and a decline in egg production in chickens and domestic water supplybird (Shawky and Sandhu, 2003). It has also been found to caus e viable mortality in wild waterfowl. The disease (DPV) strains have been found to exist from cloacal swabs of pintail ducks, wood ducks and gadwall ducks. It was also found out that wild ducks and geese that survived during the natural outbreaks remained carriers even after four years of post infection. Migratory birds who are carriers have been identified by using virological and serological methods.The role of these birds in the epidemiology and incidence in domestic and wild of duck plague have been estimated (Ziedler and Hlinak). There was ready evidence that the most certain obtain of infection was DPV- carrier and American black duck. These birds entered through the major flyways (Kidd and Converse, 2001). This conclusion was reached after the major epizootic of duck plague in wild waterfowl in the US way back in 1973. It has also been found out that the convalescent migrants are the silent carriers for DPV control in poultry. Measures to minimize the diffuse of the disea se should include bio-security, decontamination of the environment and eradication of affected flocks (Pearson and Cassidy, 1997 Converse and Kidd, 2001).Egg assoil syndrome virus (EDSV)The EDSV is a vertically transmitted disease in poultry. It causes low egg production with high fragility of eggs. It also leads to substantial descend in fertility and hatchability of the eggs. This virus (EDS-76) is classified under group ternary of the Adenoviridae. The disease is usually common in layer chickens. Ducks and geese are intellection to be the natural hosts for the virus (McFerran and Adair, 2003). Migratory ducks, egrets, gulls, grebes and wild geese have been found to have been found to have antibodies against this virus (Malkinson and Weisman, 2003 Kaleta et al., 1985). Migratory anseriforms is thought to be disseminating EDSV. The sporadic infections in poultry can be connected to the spread of the disease from wild ducks and geese to domestic flock. The spread can be through sharing of topeing water which has been contaminated with gunk of infected birds. These droppings pollute the water thus making it a source for breeding of the virus (Hubalek, 2004 McFerran and Adair, 2003).Psteurella multocidaP. multocida is a bacteria that has bipolar staining feature. It is the entiological agent of avian or fowl cholera. The disease is highly significant and economically important and causes mortality which is significant in both domestic and wild birds (Wobeser, 1997 Hubalek, 1994 break apart et al., 2004). Avian cholera spreads rapidly through waterfowls. It is known as a disease with carrier status. The disease is very prevalent among the ducks and turkeys followed by chicken are more susceptible. The disease generally spreads faster among the young ones (Glison et al., 2003). closely 70,000 migratory ducks and geese were reported to have succumbed to the infection during the US outbreaks in 1979 (Brand, 1984).The heavy(p) bird aggregation due to the na ture of waterfowls being gregarious, prompts the outbreaks of AC. The bacteriums ability to survive in water for a long period of up to several weeks is high. These aspects enhance the chances of rapidity and the extent of disease spread (Botzler, 1991 Glisson et al., 2003).Those birds that survive during the outbreaks and thus recover have been reported to be long carriers of the infectious agents. These birds later help in dissemination of the agent to various distant wetland locations. Free ranging wild birds have also been infected with the bacterium though the greatest magnitude of losses is experienced by the close of waterfowls (Hunter and Wobeser, 1997 Glisson et al., 2003).Chlamydophila psittaciThe disease (chlamydiosis) is caused by an obligate intracellular bacterium called C. psittaci. It is a ancestral disease of pet birds and poultry having zoonotic implications. It is also considered as a List B disease in parrots, parakeets and humaneitys (A ndersen and Vanrompa y, 2000). Chlamydiosis affects all types of poultry and is usually systematic though occasionally fatal. The disease is often transmitted by inhalation or even ingestion of infectious faecal dust. Birds like wild ducks, egrets, sparrows, grackles, gulls other bird species have a significant author of the bacteria that can spread the disease. This can be through direct contact or infectious aerosols to a variety of vertebrates including human beings and poultry (Grimes et al., 1979 Page, 1976 Kaleta and Taday, 2003 Brand, 1989 Andersen and Vanrompay, 2000).Research has shown that some chlamydial strains which are not pathogenic to migratory avian hosts are highly virulent for humans and domestic fowls. Suggestions have been made that grackles and thus migratory birds are potential reservoir hosts which can play an important role in the transmission of unit of ammunition of the bacterium C. psittaci in nature (Roberts and Grimes, 1978). The mechanisms by which the bacteria is intro duced in domestic flock is clearly not understood. This is mysterious because wild birds are also infected by the same strains as domestic flock (Andersen and Vanrompay, 2000). This calls for an sweetening in the surveillance and screening in order to find the role of wild birds in the epidemiology of infection in domestic birds (Schwarzova et al., 2006).Other pathogens caused by migratory birdsWild or migratory birds also aid in the transmission of other types of pathogens in animals as well as human beings. There are various animal diseases that are a resolution of the interaction between them and the migratory birds. In the ecological system, living things always interact in order to create a balance. During this time, birds that are infected or carriers of bacteria get to interact with other living things. In the process, they make the environment contaminated and thus high risk of these animals assure diseases. For example, birds and other animals may share drinking water. I f these birds are infected, they pass on the virus into the water thus making it contaminated. As the animal drink the water, they ingest bacteria and thus contract diseases. Human beings may use these animals as food. Being that the flesh is contaminated, they automatically get the bacteria or virus into their systems. Through this channel, both the animals and human beings contract diseases. The main source of the infection is the bird.There are a number of infections that are transmitted by birds to other animals. Among them include West Nile Fever (WNF). This is a Flavivirus belong to family flaviviridae. It is a mosquito-borne virus which can result in fatal cephalitis in human beings. The effect can also be on equines and avian species (Hubalek and Halouzka, 1999 Komar, 2000 Rappole and Hubalek, 2000). This disease is maintained in a cycle of epizoonic transmission between mosquitoes and birds. Human and horses are the incidental hosts in this case. The migratory birds are cen tral to the epidemiology of WNV infections. This is because they are considered as the main amplifying hosts in the transmission process (Reed et al., 2003).Migratory birds also play a crucial role in the dissemination of zoonotic and enteropathogenic bacteria that cause other infections in animals. For example, wild birds aid in the spread of Campylobacter and Salmonella. The incidence of infections in human beings by Campylobacter jejuni is on a continuous rise. The disease proves to be fatal at some acute stages and thus has led to the deaths of many. From research, it has been proved that the main transmitters of the bacteria are wild birds. The disease is usually rampant in places characterized with high humidity and high temperatures.Research is still on to establish whether there are other transmitters apart from wild birds (Sacks et al,. 1986 Tomar et al., 2006). The contamination of the surface water with the bacteria is largely attributed to aquatic and wild birds. Likewis e, in the case of Salmonella infections, remnants of S. enteric (Typhimurium and Enteritidis) have been isolated from many species of birds. These birds include gulls, ducks, terns, finches and sparrows. Research has confirmed that migratory birds are involved in the dissemination of these bacteria.