Preventing the Transmission of Zoonotic Diseases in Africa
Victoria Lyons, Grace Luttrell, Emily Segal
A zoonotic disease is a disease that can be passed from animals to humans.
Problem Statement: In many regions of Africa, zoonotic diseases pose an extreme threat to human and animal safety. It is our goal to decrease the prevalence of diseases through sanitation and education, in order to improve the quality of life in these regions.
|Location of Oodi in Botswana|
Our focus is on the rural village of Oodi, Botswana in Southern Africa. We have chosen to focus on this area because one of our group members, Emily Segal, has been to the region a few times and knows a lot about how they operate/what infrastructure they already have in place.Victoria and Emily are animal science majors at Cal Poly, and Grace is a business major. As a group, we are focusing on the interests and ideas provided from this background. We want to help animals, but we want to do it in a way that will also help people and do so in an economically sound way. We decided to focus on this problem because it is important to start from the ground up; where there are sick animals, there will be sick people. Improving the livelihood of these people by providing them with healthy food sources (such as in the case of their food animals) will cause more good than simply improving their health alone. It is best to reduce stress and give them a healthier dietby creating a way for them to be sure that they will have healthy food sources and will have a reduced hance of getting sick.
Cattlehave a large amount of value among the people of Oodi. These animals provide them with food and their main source of income. Ensuring that these animals are as healthy and economically valuable as possible is a main concern for these people.The people of Oodi are also in the process of switching over to a feedlot system with their cattle, which means that they are confining their cattle and feeding them high-energy grains in order to increase weight gain late in life just prior to slaughter. They want to begin to sell these cattle to offshore markets in order to increase their profitability, and cannot do so until they decrease the prevalence of disease in their cattle. This is yet another reason that reducing disease among cattle is important.
The government pumps in clean water to the village from outside sources in order that the people exclusively have relatively clean, potable water. However, this water is not available to the livestock of the area. Therefore, the livestock can only drink water from natural sources, and water available from these sources is contaminated through its exposure to wildlife and the soil microbes of the area. The wildlife carry bacteria and viruses which they transfer to the water, and the soil is a huge source of pathogens. Overall, obtaining water that is clean to begin with for the livestock is impossible because it is just not available.
We aim to prevent waterborne diseases in order to reduce or even eliminate the transfer of these diseases from animals to people, and have found multiple methods for doing so. Each has its advantages and disadvantages, but has its own way of killing bacteria and pathogens in the water in order to make it safe for consumption by cattle and even humans.
Benefits of Reducing the Prevalence of Zoonotic Diseases
– Healthier People and Healthier Animals
– Less animals dying of disease, which in turn means more food for the people raising those animals
– More animals available for sale, and therefore more money/traded goods to be used by the people who need it most
1. Taenia Saginata, also known as “Cysticercus bovus”: This microorganism is prevalent in Oodi, Botswana, and forms cysts in muscle tissue. If the affected muscle tissue is consumed by humans, sickness ensues.
2. Blood Flukes: Spread by water; infects mammals by swimming into open wounds. Live in bloodstream and lay eggs that are excreted by animal. Animals spread them, and this makes people more prone to being infected by the parasite.
3. Anthrax: live in contaminated water; spread by inhalation or ingestion of spores, so infected food animals are extremely likely to pass to humans; cause a range of symptoms that mimic those of a severe upper respiratory infection, along with nausea and vomiting.
Water Purification: Several Viable Options Are Available
– Ozone can be used to kill many strains of waterborne bacteria
-An ozone generator can be made relatively easily by each family in the village, and requires only a small financial investment
-Considering that animals need more water than humans, large amounts of water must be purified at a time in order to have enough drinking water for the animals as well as for the people. It is for this reason that multiple Ozone generators should probably be used to purify large amounts of water.
-Sterilized water can be kept in large tanks made of polyethylene plastic. This material is sturdy and long lasting, and very easy to clean. It would be necessary to clean these tanks with soap and possibly a little bleach before use, but then they would stay relatively clean because only purified water (no bacteria, etc.) would be inhabiting them.
-Ozone generators would need to be powered somehow; Botswana has an established electrical grid, and hooking the ozone generators up to this grid would be an easy solution and would not require a lot of maintenance. More than enough power for each generator can be supplied by the grid
-Each family would need their own ozone generator/water tank, so that herds would not mix and therefore cause potential disease transmission between all animals; hoof and mouth is an important concern in this region, and can wipe out an entire herd of cattle, and so mixing of animals is important to reduce the risk of such an event
-Ozone made within the generator would bubble up into the water from underneath the water tank
2. UV Light
-When DNA is impacted with UV light, necessary proteins are deactivated, and so microbial cells lose all function
–Kills 99.99% of microorganisms without adding chemicals
-Dirt/debris in water can protect microbial cells from UV rays, and so water must be filtered first to remove large sedimentaion
–This method of water purification has been proven effective all over the world; a company called Waterhealth just received a $10 million grant to establish systems to purify water using UV light in India, Central/South America, Africa, and Asia
Waterworks is a system specifically designed for use in the developing world due to its affordability and effectiveness
-This system was originally field tested in South Africa, and was found to kill 99.99% of microorganisms after filtration that removed sedimentation, cryptosporidium, and giardia
-It is now used in Mexico, Bangledesh, South Africa, the Philippines, India, and many other places
-The cost to purify is about $0.02/ton of water, and the rate of purification is 4 gallons/minute
-Maintenance is only required every six months to check the bulb/filter, and a quick cleaning of the outlet chamber is needed every two months to control biofilm build-up
-Necessary exposure time to the 40 watt UV bulb is 12 seconds
-The system can be powered by the equivalent electricity from a car battery (Oodi has an electrical grid that is more than capable of providing this power), or a 60 watt solar cell
-Purified water must be consumed within 36 hours, or it must be exposed to the UV again in order to ensure complete purification
-The cost of the system is about $600
-The best part is that no skilled operator is required, the system works without pressurized water because gravity is enough to pull water through the filter and the UV chamber, the entire system is only 15 pounds and the size of a microwave, and it uses 6000 times less energy than boiling
3. Bio-Filtration (Slow Sand Filter)
– Bio-filtration (also known as slow sand ) uses non-pathogenic microbes to outcompete waterborne pathogenic microbes for food sources as the water is being filtered through a system of rocks and sand
– These filters are easy to put together and require little to no maintenance sometimes for many years
– Once a colony of microbes is established on the initial ‘layer’ (which is often some substance similar to white quartz) the filter can kill up to 99.99% of waterborne pathogens this also means that cleaning the system is inadvisable as a fresh colony will need to be established before the system can be effectively used again
– A portable and cheap system can cost roughly $400 and can filter approximately 0.125 gallons per minute
– This system is currently being used for disaster relief in many countries and is easily obtainable
4. Solar Still
-A solar still uses energy from the sun in order to evaporate water, turning it into condensation, and then recollecting the clean water in a separate bin; During the process, salt, E.coli and cryptosporidum are all removed as well as other microbial organisms
-Using two water troughs, one trough would hold dirty water while the other trough would hold the clean water once the water had been condensed and collected
-The solar still is easy to build and requires a glass sheet placed at an angle as well as a tube that connects one trough to the other so that the water can run into the clean trough
-On average, the trough would cost around $200 or less to build
-Despite the benefits of the solar still method, the method takes a long time to collect water and is entirely dependent upon the weather for quick evaporation to take place
Comparison of Water Purification Systems, Including Advantages and Disadvantages
After weighing the advantages and disadvantages of each system highlighted above, we have come to the conclusion that the best system for the area is bio-filtration. It requires the least amount of maintenance and is very efficient for killing pathogenic microbes. We will focus on the costs and labor behind implementing this type of system in Oodi in our proposal for the NCIIA grant.
Why not Halogens?
-Chlorine is often used in a similar fashion to the use of ozone; it is used to oxidize bacterial cells and therefore kill them by destroying cellular membranes
–It requires careful monitoring and education to make it an effective water treatment; this type of skill/capability is not present in Oodi, and so this system seems impractical for the region
–Use of chlorine to kill potential pathogens could affect the palatability of the water, which means that the cattle may not drink what they need; this is dangerous to animal survival in Oodi’s dry climate, and losing cattle would not help the people to be successful
Education of the People
-Educating the people about disease transmission and good health practices can be an easy and very effective way of reducing the prevalence of diseases in Botswana
-Since the people have electricity and gather each night to watch television programs together, it would be very efficient to show the people a simple video about the hazards of poor heath practices and how they can take better care not to spread disease-causing agents from animals to people and even from people to people. This video could be short and to the point, as long as it got the message across to the people that being more careful about spreading bacteria can really benefit them and help them reach become healthier and happier. An example of a type of video that can be shown is something simple like the video Pete showed in our class about Sodus that used drawings and simple dialogue to get the point across.
-Such a video could include information about washing hands between handling animals and handling meat, washing food before preparing it (both meat and non-meat products), and sterilizing water in order to kill the agents which cause the most prevalent diseases in their village
-The people also enjoy making posters and displaying them in public places, and so some posters or pamphlets about water sanitation and the spread of zoonotic diseases could be useful
-Botswana is a dry country, and so obtaining the water to place in the tanks to be sterilized could be difficult; however, using the same water sources that have always been used to water cattle and simply adding the step of purifying the water will be the best way to address this problem.
-The people could not be receptive to an education about things that they have not worried about before; they may not want to change their ways. The best way to address this is to repeatedly emphasize how important it is to practice healthy habits and how doing so can help the people live a better and healthier life. Purifying the water and establishing good health practices can also help the people achieve their goal of competing in the international beef market, and having healthier food sources overall.
-The financial requirements for this project could be difficult to fulfill on the budget that the people of Botswana live on, however obtaining a grant for this project should take care of this problem.
-Disadvantages for each system are listed in the above chart.
The Bigger Picture
As Botswana tries to find its role in the global beef market they have been drawn to the systems that make up the majority of the developed world systems of beef production; namely feedlot systems. Feedlot systems are still around today in developed countries because they simply are one of the best ways at producing the meat that their markets prefer, and botswana is trying to replicate that success. There is no way to know if this system would actually be beneficial with their markets and in their climate. A feed lot system might prove to be more effective at monitoring and raising cattle so that their markets will grow or it might prove a ‘feeding lot’ for the wildlife instead of the people.
For more information regarding each purification system, please visit the following websites:
UV Waterworks: http://www.lbl.gov/tt/success_stories/practical_application/uv_waterworks.html
Solar Still: http://www.solaqua.com/solstilbas.html