Dynamics of Rift Valley Fever and Its Recent Epidemic - Term Paper Example

Name: Course: Instructor: Date: Dynamics of Rift Valley Fever and its recent epidemic Rift Valley fever (RVF) is an acute, febrile, viral, arthropod-borne zoonosis that affects ruminant domestic and wild animals such cattle, sheep, goats, camels, African buffalo, dromedaries, white rhinoceroses and waterbucks. In their research, Davies and Martin studied that sheep appears to be more venerable to the virus than the rest (Davies & Martin 2003). Studies have shown that the disease can be transmitted to human beings through aedes mosquitoes and other blood sucking insects such as flees and ticks, through direct contact with fresh blood of an affected animal for instance when slaughtering and drinking non-boiled milk of infected livestock (Anyamba 2002). According to Laboratory research, experiments and studies RVF is caused by a three-stranded RNA virus classified as a member of the family Bunyaviridae, genus Phlebovirus (Geering et al 1995). As described by Ghabrial, the virus is hepatic and in many cases it is haemorrhagic and it replicates rapidly. In adults, its viral replication takes place mainly in the liver and spleen whereas in fetuses and neonates, it occurs in the brain. The virus can be inactivated by using detergents and solutions with low PH (Ghabrial 1998). In livestock, the disease may be latent in un-pregnant females but in pregnant ones, the disease is characterized by a huge rate of abortions and death of the new born (Linthicum et al 1999). Botros et al noted that in humans, the incubation period is 2-6 days. People infected with RVF usually have a flu-like illness with symptoms such as fever, weakness, muscle pain and weight loss. The infection can also cause severe bleeding, brain inflammation and severe eye problems (Botros et al 1989). RVF was first detected in the early 1900s. The cause was not recognized until the year 1931 when a there was a large epizootic outbreak of cattle and sheep in Rift valley province near Lake Naivasha in Kenya. There were a hundred percent of sheep abortions and the mortality rate of young lamps aged between one to two weeks was also high. RVF outbreak occurs when there is abnormal heavy down pour such as the El Nino (Brès 1981). The major outbreaks of the disease are as follows. In the year 1950-1951, there was a major outbreak that accounted for roughly one hundred thousand mortality in sheep and five hundred abortions for the same. There was also an estimate of seventy thousand mortality for cattle and camels and one hundred and twenty five thousand abortions for the same (WHO 1982). In 1977 and 1983, there was a disastrous outbreak in Egypt in the Nile delta where there was over one million livestock mortality and abortion cases and eighteen thousand human cases. Five hundred and ninety six people died, others went bride and some had brain damage. Majority responded well to treatment (WHO 1985). In 1987 there was an out break in Senegal River Basin and Mauritania where there was three hundred thousand animal fatalities (WHO 1990). In 1997-1998 there was an outbreak in Kenya and Tanzania eight nine thousand human cases and over five hundred cattle and sheep cases. In 2000 for the first time the virus was detected outside Africa in Saudi Arabia and Yemen Saudi where there were eleven thousand human cases that resulted to 40 deaths reported. There were six hundred thousand animal cases with over one hundred and fifty thousand fatalities. In 2002 there was an outbreak in Gambia, in 8 locations. In 2003, 2004 there was an outbreak in Mauritania, Senegal, Egypt, Yemen and Saudi Arabia (WHO 2005). The immediate and broader contextual factors that caused the outbreak Climatic conditions – Ghabrial noted that, extreme weather changes in Africa are key triggers of rift valley fever. In Africa, Yemen and Saudi Arabia, rift valley fever pandemics are closely related to long dry spell followed by abnormal heavy rainfalls such as the Kenyan El Nino of 1997/98, there was a major outbreak of the disease (Ghabrial 1998). Also, according to Coetzer and Tustin Rift valley fever pandemic mainly emerges during abnormal heavy rainfall seasons that are accompanied with heavy flooding. The above average rainfall creates room for aedes mosquito eggs to hatch. These eggs are in nature infected with the Rift Valley Fever virus and when they mature, the resultant mosquitoes vector the virus to the animals on which they suck blood from (Coetzer & Tustin 2004). Another effect of heavy down poor is health whereby, people living in these areas are highly affected in that, due to heavy flooding, their temporary structures and sanitation facilities are swept away such that they are forced to spend nights out thus prone to aedes mosquitoes (WHO 1982). A study carried out by Stephenson et al in Africa showed that Rift Valley Fever outbreak emerges in arid and semi-arid areas where majority of the inhabitants in these areas are pastoralists. The pastoralists either put up temporally structures as shelters or spend nights out. It is well known that that sleeping outdoors at night in areas where Rift Valley Fever pandemics occur could be a major risk factor for exposure Rift Valley Fever vectors mainly the aedes mosquitoes. Also, people working in animal health professions such as veterinarians, slaughterhouse workers, and dairy farmers have a higher chance of contracting the virus from any infected livestock. International researchers who travel to the areas where the virus may emerge enhance their chances of being contaminated with the disease (Stephenson et al 1990). Lack of internal and social security is another factor that leads to RVF emergence in that professions who can help to stop the virus from spreading cannot go to these areas because at any given time racial conflicts may arise and this is life risking. For instance, in Kenya cattle rustling is not only a major issue but a common issue too where heavy fire exchange is involved. The end result is civilian casualties and this makes it hard for veterinaries to accept working with such communities. Civil wars are also dominant in the horn of Africa especially in Sudan and Somalia making it difficult to undertake a viable research all over the region. Another factor is corruption – all the five countries in the horn of Africa i.e. Somalia, Djibouti, Eritrea, Ethiopia and Kenya have many issues of corruption especially in the government offices. It happens that when the finance ministries set aside funds to prevent the spread or even emergence of RVF, only a small amount is spent in the project meaning that if five hundred thousand cattle were to be vaccinated, only one hundred thousand will be vaccinated, the rest of the funds end up in individual pockets (Morrill et al 1990). Another factor is economy in that most of the people living in the prone areas are usually poor. If the government does not treat the animals on their behalf, transmission enlarges causing huge loses and casualties since the herders cannot afford to cater for the medication of a huge number of livestock (Coetzer & Bernard1977) Control measures of Rift Valley fever As documented by Brès there are certain control measures which are used to control the spread of RVF in animals and in human beings. Timely detection of RVF is a benefit to efficient control of the disease control procedures in humans and animals. Most human beings who have been diagnosed with RVF are comparatively meek and cover a short duration of time; in essence there exists no specific treatment for such patients. Human’s beings with more severe cases the major cure is a wide-ranging supportive therapy. Also an inactivated vaccines available and can be used to cure RVF. The vaccine is not for commercial sale and IS only used to protect the health practitioners and veterinary doctors who are at high jeopardy of exposure to RVF (Brès 1981). In animals, occurrence of RVF is barred buy using a constant programme of vaccinating the animals. This is done by the use of both modified live attenuated virus and inactivated virus vaccines, these vaccines are in most cases used to thwart the quick spreading of RVF. Only one dose of the live vaccine is required to provide long term immunity but the vaccine that is currently in use may result in spontaneous abortion if given to pregnant animals. The inactivated virus vaccine does not have side effects, but multiple doses are required in order to provide protection which may prove problematic in endemic areas (Hoogstraal et al 1979). Another control measure that is applied to prevent the spread of RVF is animal immunization. It is usually done before the outbreak of the disease. This control measure should not be implemented if the outbreak has already occurred since animal vaccination may intensify the outbreak of the disease. Another control measure that can be implemented so as to control the spread of RVF is the restriction of movement in animals. This control method has proved to be efficient in dawdling the spreading out of the virus from the areas that have been infected to those areas that are uninfected. Another control measure that is mostly implemented is the establishment of an active animal health surveillance system this measure is mostly used in the detection of new cases of the diseases. It provides warning signs to the human beings, the society and the government (Hoogstraal et al 1979). The other control measure that is implemented so as to lessen the spreading of the disease is vector control. This method mainly involves the practical control the widening coverage of RVF it involves controlling of the vector that transmits the disease and also the safeguard against the bites of the vector. Larviciding measures which are implemented at the mosquito breeding spot are termed to be the most effectual form of vector control if the breeding sites can be undoubtedly recognized and seems to be small. This method is usually applicable in sunny periods. Another control measure that is applied is RVF forecasting and climatic models. By the use of forecasting one is able to anticipate the climatic conditions that are normally linked with an augmented risk of outbreaks; this method may at times improve disease control (Hoogstraal et al 1979). Public health challenges The RVF being a disease that is spread through mosquitoes is a disease that easily spreads from one regions and the other and hence the political disintegration of the Horn of Africa countries poses a challenge to public health officers in containing the disease. The lack of peace in Somalia and the political turmoil in the Horn of Africa countries for instance, the post election violence in Kenya are just but examples of political instability that hinders public health officers in containing RVF epidemic. Due to the political hick ups trailing these developing nations makes it hard for public health officials to have transnational programs for mitigating the disease. These factors coupled with periodic nature and the rapid evolution of the disease poses challenges for public health officers (Daubney 1931). Most of the Horn of Africa countries lack the exotic breed of animals for instance cattle as this would have helped in serving as disease hosts and will therefore help in acting as early indicators of RVF other than waiting for humans to get infected so that public health officers discover the outbreak of the disease faster (Hoogstraal et al 1979). When taking a closer look at the Horn of Africa countries, they are all developing nations otherwise called the third world countries whereby these countries are being affected by global warming which is evidenced through the massive floods occurring in third world countries and other indicators of global warming. The climatic conditions in the countries are similar and hence the disease vector finds easy grounds for breeding and eventually spreading (Stephenson et al 1990). Lack of Non – Governmental Organizations intervention is also a challenge to pubic health officers, whereby, the tribal clashes and civil wars in the Horn of Africa countries do little in encouraging establishment of NGOs. On the same note too, private efforts in investing in public health is deterred due to the unstable political situation in the horn of Africa countries for instance Somalia (Daubney 1931). Government issues for instance lack of planning to cater for such epidemic is widespread in the Horn of Africa countries. For instance, the response accorded to such zoonotic diseases does not reflect the government’s will in contacting the RVF epidemic and public health officers in the absence of government will or plans to contain such epidemics can do little in such scenarios. Even where there is government intervention, issues relating to public health are not closely monitored for instance Kenya, and it becomes very hard for corrective actions to be taken in contacting the RVF epidemic. Finally lack of technology is a major challenge to public health. With the absence of modern technology, RVF epidemic is amplified while in actual sense it is a modest epidemic that can be contained with modern technology for instance faster communication between the horn of Africa countries at the slightest indication of the epidemic, disease surveillance in the countries and laboratories that are to confirm the epidemic in the initial stages instead of waiting for the epidemic to manifest in humans (Stephenson et al 1990). The expected challenges faced in underdeveloped region in politically complex situation Health - There are a few and in some regions no medical centers in arid and semi-arid areas in the horn of Africa. These areas are prone to several diseases like malaria, RVF, typhoid, cholera and others, snake bites, attacks by wild animals and the like. If a person is infected or attacked by the wild animals he might end up losing his/her life merely because there is lack of adequate medical facilities (WHO 2004). Corruption – in the horn of Africa, if a person wants help from a government office, you will either wait for long to get the service or be corrupt and get the service you want in a few minutes. As a result a person might end up failing to conclude his/her work. Insecurity is another major issue in the horn of Africa due to tribalism and political crisis. In Somalia, no researchers or professional workers can dare go there due to the current political crisis and civil wars. In north and southern Sudan, there is civil war too making it herd to take measures that can help curb the disease. In a country like Somalia, security is at stake. Today the country is in the hands of the al shabaab militia and according to them foreigners are spies, such that if RVF emerged at any time all the livestock in the country would die since no one is allowed to get there. Transport is another hindrance. Around the horn of Africa especially the arid and semi arid areas, there are poor road networks and in some areas there is none. This makes it difficult to move from one are to the next References Ghabrial, S. (1998). Origin adaptation and evolutionary pathways of fungal viruses. NY Columbia Uni. Press Coetzer, J., Bernard, H. (1977). Rift Valley fever viruses as etiological agents. chicago Platinum press Linthicum, K., A. Anyamba, J. Tucker, W. Kelley,M. Meyers, C. (1999) Climate and Satellite Indicators to Forecast Rift Valley Fever Epidemics in Kenya, Science, London penguin press. Anyamba, A., Linthicum, K. J., Mahoney, R and Tucker, C. J.(2002), Mapping Potential Risk of Rift Valley fever outbreaks in African Savannas using Vegetation Index Time Series Data. Photogrammetric Engineering Remote Sensing: Special Issue – Remote Sensing and Human Health, 68(2): 137-145. WHO/FAD Working Group on Rift Valley fever. Rift Valley Fever: An Emerging Human and Animal Problem. WHO Publication No. 63, Geneva, 69pp, 1982. WHO/FAD Working Group on Rift Valley fever. Rift Valley Fever: An Emerging Human and Animal Problem. WHO Publication No. 112, Geneva, 69pp, 1985. WHO/FAD Working Group on Rift Valley fever. Rift Valley Fever: An Emerging Human and Animal Problem. WHO Publication No. 243, Geneva, 69pp, 1989. WHO/FAD Working Group on Rift Valley fever. Rift Valley Fever: An Emerging Human and Animal Problem. WHO Publication No. 345, Geneva, 69pp, 2004. Botros, B., Omar, A., Elian, K., Mohamed, G., Soliman, A., Salib K.( 2006) Adverse response of non-indigenous cattle of European breeds to live attenuated Smithburn Rift Valley fever vaccine. 78:787-791. Davies, G., Martin, V. (1997). Recognizing Rift Valley fever. FAO Animal Health Manual number 17. 2003. Geering, A., Foreman, J. Nunn, P. (1995). Exotic Diseases of Animals, Australian Govt. Publishing Service, Canberra; p.218- 224. Stephenson, H., Meegan J., Morrill C., (1990). Rift Valley Fever Virus. In Virus Infections of Ruminants, London Science Publishers. Brès P. (1981). - Prevention of the spread of Rift Valley fever from the African continent. Contributions to Epidemiology and Biostatics. London, penguin publishers. Brown C. & Torres A. (2008). - USAHA Foreign Animal Diseases, 7th Ed. Committee of Foreign and Emerging Diseases of the US Animal Health Association. Boca Publications Group, Inc. Coetzer J. & Tustin R. (2004). - Infectious Diseases of Livestock, 2nd ed. Oxford University Press. Davies F., Linthicum, K., and James, D. (1985). Rainfall and epizootic Rift Valley fever. Bull. WHO., London John Wiley & Sons. Morrill J., Mebus A., and Peters J. (1997). Safety and efficacy of a mutagen-attenuated Rift Valley fever vaccine in cattle. London Pearson Education. Hoogstraal H., Meegan J., Khalil, G., Adham, F. (1979). The Rift Valley fever epizootic in Egypt 1977-78. NY, Prentice-Hall. Daubney, R., Hudson, J., Garnham, P. (1931). Enzootic hepatitis or Rift Valley fever: An undescribed virus disease of sheep, cattle, and man from east Africa. J. Pathol. Bacteriol., Chicago, Chicago uni. Press. Read More