Rift Valley Fever (RVF) is a zoonotic viral infection that affects farm animals and can be transferred to humans. It is stretched further by mosquitoes of the Aedes or Culex genera (World Health Organization, 2011). The RVF disease is caused by the Rift Valley Fever (RVF) virus, which belongs to the genus Phlebovirus and the family Bunyaviridae. The disease was originally reported in the domestic animals of Kenya, in and around 1915, and the virus was possibly isolated in 1931 (Rift Valley Fever, 2011). The historical past of the disease indicates the outburst of Rift Valley Fever in the areas of sub-Saharan Africa and in the Arabian Peninsula, where linked human cases have been detailed in Egypt in 1977-78, in Kenya and other neighboring countries in 1998, Saudi Arabia and Yemen in 2000, and again in the horn of Africa region in 2007. Cases have been reported in 2011 in South Africa and Zimbabwe too (World Health Organization, 2011; Food and Agricultural Organization, 2011; Center for Disease Control and Prevention, 2011).
At the beginning of 2007, the RVF outbreaks were reported in numerous eastern African nations like Kenya, Somalia, Ethiopia, Eritrea, Djibouti, Madagascar, Comoros and the French island of Mayotte (Food and Agricultural Organization, 2011). Earlier in 1998, the disease outbreak happened in the horn of Africa due to the events of floods providing ample breeding grounds for the mosquitoes to multiply, and hence spread the inoculums. The incidence of the disease in the African region, later on, spread to the Arabian Peninsula as well (World Health Organization, 2011). Various public health agencies work out the feasible incidence of the virus in regions that are recognized as ‘higher risk zones’ or ‘disease hot spots’. This essay aims to discuss Rift Valley Fever as a communicable disease in politically, socially and economically deprived nations of Eastern Africa, its dynamics over time and space, epidemic occurrence, proximal and distal causes of the disease outbreak, arise of the public health challenges, the control mechanisms adopted and challenges that stand out during the entire cycle of disease outbreak to disease control.
The Disease dynamics and its recent epidemic
RVF is a mosquito-borne viral disease affecting ruminants and humans, which occur in cycles of 5-15 years. The virus infects the farm and domesticated animals like cattle, sheep, camels and goats, with the possibility of sheep infection being the maximum, and perhaps they act as the reservoirs of the inoculums for dormancy as well as propagation of the infection when the circumstances become favorable for the viruses to multiply and get transmitted from livestock to the humans, who are associated in close contacts with these infected animals. Age continues to be an influential feature for the infection to occur both in animals and humans. The rate of abortion is also higher in infected pregnant animals. Viral transmission remains one of the areas that have to be monitored. The virus may be transmitted during the animal handling procedures such as during childbirth, slaughtering, veterinary actions, or from the dumping of carcasses and fetuses. The dynamics of infection put individuals like farmers, butcheries workers, veterinarians, etc. at greater risks. The virus paves its way into the human body through some wound opening, wrecked skin, contaminated instruments, and breathing of aerosols in slaughterhouses. Lab workers handling infected samples may get affected via an aerosol mode of viral transmission. The bites of mosquitoes and hematophagous flies may also cause RVF infection. There have been reports available with the WHO that the infection may occur by drinking uncooked milk of diseased cattle. The reports do not indicate whether transmission of the disease from one human to another is possible or not, and also it has not been found to occur in urban areas (World Health Organization, 2011).
The clinical features include an incubation period of 2 to 6 days, flu-like fever, muscular pain, stiffness of the neck, light sensitivity, vomiting, appetite loss, etc. After 5 days, the virus disappears from the blood and the detectable antibodies symbolizing infection appear. There could be severe representations of the disease as ocular, meningoencephalitis and hemorrhagic fever forms, with most fatalities being reported from cases of hemorrhagic forms. The diagnostic tests include Enzyme-linked Immunoassays, Reverse Transcriptase- Polymerase Chain Reaction, and other suitable antigen detection mechanisms for the detection of the virus in the samples of the infected animals or humans, and thereby confirming the disease (World Health Organization, 2011; The Vizier Project, 2011).
The mechanistic views about the disease cycle thus possibly include the animals, humans working with those animals, flies and mosquitoes as vectors for dispersal of inoculums or the pathogen, and also the mishandling of the crisis. There is a disease management problem that aggravates the intensity of the infection during the outbreak resulting in epidemics. The recent epidemic in eastern Africa or the region better known as ‘Horn of Africa’, has been characterized by the political strife and civil wars, food insecurity, a total collapse of the community and the government machinery to handle epidemics, presence of extremely fragile and rudimentary public health facilities coupled with the late arrival of foreign aid and other humanitarian agencies (Center for Disease Control and Prevention, 2011).
The proximal and distal causation of the disease outbreak
The immediate causes associated with the disease outbreak are unusually high rainfall and flooding of the RVF-prone areas, poor sanitation systems in the community, adequate mosquito and fly breeding places, lack of mosquito control like sprays, nets, etc. The high winds also aid in the quick dispersal of the pathogen from one place to the next, where they may be picked up by the vectors for further transmission. The Horn of Africa region countries has faced similar conditions of high-speed winds, heavy rainfall and flooding that quickens the epidemic disease process for RVF (Medilinks, 2011).
The distal causes responsible for the repeated occurrence of the disease epidemic of RVF in these areas has been their continued years of political instability, civil wars, strife, social and economic instability leading to the conditions of poor sanitation, weaker health management systems, lack of food insecurity, and lack of financial resources to control emergencies. There is a total collapse of the governance that can be somewhat capable to look after its own people when there is an emergency. Such factors also impede the process of humanitarian help from various other agencies like the WHO, the FAO and other health task forces of various developed nations appointed to look after and control the epidemic situation threatening to go beyond control limits, resulting in a large number of casualties in these areas. During the period of complex emergencies such as the RVF epidemic, the affected animals and humans are needed to be provided with shelter, food, water, sanitation, and basic healthcare services. But the constraints of extremely limited resources in the hands of the governments have impeded the disease management process in these areas (Relief Web, 2011).
The public health challenges during the disease outbreak
The countries of the Horn of Africa have been deprived of basic amenities to tackle emergency public health challenges. The community system was in total disarray so the people were already struggling to meet the daily requisites like food, water, shelter, sanitation and critical health care. So the public health challenges emanated out of the need for a government-based control system in operation, which was entirely missing. The collection of significant data regarding the disease outbreak was considered to be essential so as to speedily review the emergency condition, prevention of the incidence of epidemics, presence of vigorous administration synchronization, outbreak control workings, and overall disease supervision process (Toole & Waldman, 1997).
The grave situation in 2007 demanded a quick appraisal of the disease occurrence including having the knowledge of the intensity of disease spread and risk of transmission of RVF from animals to humans, the type of likely interference, setting up and prioritizing actions, plan completion, and the most important of all to be able to provide adequate information to the outside support agencies for social mobilization. The challenges with respect to prevention aspects included site research, conditioning of shelter camps; availability of basic healthcare, water, food, sanitation, control of vectors and mass immunization understanding. The supervision system was not easy, unsatisfactory, inflexible, and lacked specificity. There should have been a system in place for systematic collection, examination and inquiry of data for proper health solutions. One needed to recognize priority health areas, scrutinize mortality and morbidity rates, classify outbreaks and monitor response, study trends in RVF incidence rate, and thus provide abundant information to help support agencies for meeting the urgency. But it was found lacking and resulted in over 4000 reported deaths (National Center for Biotechnology Information, 2011).
The control measures were adopted during the outbreak
The establishment from the affected countries approached for strategic disease control assistance to the World Health Organization, the Food and Agricultural Organization, and the World Organization for Animal Health. The joint representation of these agencies along with other task forces such as the Center for Disease Control, USA participated in various outbreak control tasks such as management of the infected subjects, surveillance, community support and mobilization, medical healthcare provisions, and avoidance and intensification of the hospital or shelter camps infection control systems (Medilinks, 2011).
There were two ways to look for the control of the disease spread. The first was to control the infection in animals, and the second was to control infection in humans. The control of disease in livestock remains a challenge as the entire operational effort goes into saving human losses. Few capable nations were able to prepare and refine the health component of the emergency monitor and response plan, and that included a good early warning system by climate forecasting and models (IRIN News, 2011). NASA played an important role in early warning systems predicting the occurrence of the disease outbreak by making use of data related to temperatures of the sea surface, rainfall, and flora cover in and around the prone regions (National Aeronautics and Space Administration, 2011). An earlier disease outbreak in 1997 forced researchers to look for possible satellite-based data collection to have a correct prediction about the incidence of the disease in the future and a decade of extensive mapping by NASA did provide an accurate prediction for 2007 occurrence. Since there is no human vaccine, only animal vaccines are available to the early predictive information regarding the disease assumes greater importance as it gives additional time for preparation (Anyamba, A., et al., 2009). It becomes more pertinent to understand the exact causes for such a disease outbreak like the relationship between mosquito life cycle and the availability of extensive vegetation in the area (National Aeronautics and Space Administration, 2011). NASA thus established the importance of a potent early warning system as a strategic tool to contain disease outbreaks by providing ample time for preparation against such complex emergencies (NASA Earth Observatory, 2011).
With the availability of animal vaccines, it was possible to prevent their losses, but the crux is that during such an emergency, one always protects human losses. A sustained animal immunization program can help to contain the disease. But a good animal health monitoring system will always remain a challenge, as it was experienced during the 2007 crisis. The measures were taken to control infection in human healthcare settings. There were attempts to control vectors too. In fact, such measures are more effective when they are done before than when the disease has already spread. There are reports of samples being studied over a defined time span to understand the disease mechanics (ClinicalTrials.gov, 2011).
The expected challenges faced during the control operations
The challenges in meeting such a complex emergency amount to factors like effective coordination among various units of disease emergency plan, monitoring and response systems. The lack of knowledge among the people about the disease also poses a tough challenge during the process as it hampers the efficiency of the total management. Having a sufficient number of people in the rapid response team is always a challenge. The provision of information to the helping agencies from the local authorities as there is language, cultural barriers, etc., poses an extra challenge. The rapid dispersal of infection due to high winds, continuous rainfall and flooding also pose a difficulty. There is a challenge to provide a continuous supply of food, water and medicines (Relief Web, 2011).
There is also an evident problem of the different fighting groups in these wars-stricken countries as they try to hamper the supply of food, medicines, clean water, etc. by attempting to loot and even kill the individuals involved in aids. The problem of migration and travel to other far-off nations increases the disease spread (IAMAT, 2011). Thus a complex emergency like an RVF disease outbreak may appear to be spread to social, economic, political and international relations spaces.
The Rift Valley Fever outbreaks have been a cause of concern in affected nations, while the climate changes with the occurrence of flooding and drought have put virus-free nations at risk, so a need to be alert and adopt protective measures to safeguard economic and human losses. There is a need to develop a human vaccine against the disease. The animal health surveillance systems should be robust. The education of the public to meet such a complex emergency has to be taken on a priority basis and the spread of the public health messages must occur periodically. The outbreak also stresses the importance of the need for sustained collaboration between the various entities involved in the process of disease epidemic administration like the health establishment and veterinary, entomologists, environmentalists and medical biologists, as the best combinatorial strategy to prevent and control RVF in the future.
References
Anyamba, A., et al. (2009). Prediction of a rift valley fever outbreak. Proceedings of National Academy of Sciences, 106(3), 955-959. Web.
Center for Disease Control and Prevention. (2011). Rift Valley Fever. Web.
Center for Disease Control and Prevention. (2011). Rift Valley Fever, Mayotte, 2007-2008. Web.
ClinicalTrials.gov. (2011). Rift Valley Fever in Kenya. Web.
Food and Agriculture Organization. (2011). Flare-up of Rift Valley Fever In the Horn of Africa. Web.
Food and Agricultural Organization. (2011). Geographic Distribution. Web.
IAMAT. (2011). Rift Valley Fever. Web.
IRIN News. (2011). Africa: The art of predicting Rift Valley Fever outbreaks. Web.
Medilinks. (2011). Madagascar: Rift Valley Fever hits the island. Web.
National Aeronautics and Space Administration. (2011). NASA study Predicted Outbreak of Deadly Virus. Web.
National Aeronautics and Space Administration. (2011). Rift Valley Fever. Web.
NASA Earth Observatory. (2011). Rift valley fever risk assessment. Web.
National Center for Biotechnology Information. (2011). Rift Valley Fever. Web.
National Center for Biotechnology Information. (2011). Rift Valley Fever: Veterinary aspects and impact for human health. Web.
National Center for Biotechnology Information. (2011). The 2007 Rift Valley Fever Outbreak in Sudan. Web.
Relief Web. (2011). Eritrea FEWS Eritrea Food Security Update: September 2000. Web.
Rift Valley Fever. (2011). In Wikipedia. Web.
The Vizier Project. (2011). Rift Valley Fever in Kenya, Somalia and the The United Republic of Tanzania. Web.
Toole M.J., & Waldman R. J. (1997). The public health aspects of complex emergencies and refugee situations. Annu Rev Pub Health, 18: 283-312.
World Health Organization. (2011). Rift Valley Fever. Web.
World Health Organization. (2011). Rift Valley Fever in the United The Republic of Tanzania. Web.