Tropical Health Matters

According to the UN Food and Agriculture Organization (FAO), about six years ago following a global food crisis, a United Nations high-level task force called for a paradigm shift in urban planning, to one that encourages urban and peri-urban food production. By including urban agriculture in urban land use considerations, planners hoped to achieve benefits ranging from improved food security, economic development to greener environments.

FAO recognizes that there are complex political issues involved in meeting the vision of promoting urban agriculture, including basic access to land, water and other resources, before the benefits can be realized. The issue is further complicated by malaria in some urban environments.

Prathiba De Silva and John Marshall observed that, “Malaria transmission in urban and periurban areas is highly focused around vector breeding sites, which tend to be more numerous in areas of lower socioeconomic status. Control strategies should therefore adopt an element of spatial targeting rather than targeting a wide urban area uniformly. Vector breeding sites are common in areas with slum-like conditions and in areas where urban agriculture is practiced.”

In another study Christophe Antonio-Nkondjio and colleagues concluded that, “The data confirm high selection pressure on mosquitoes originating from urban areas and suggest urban agriculture rather than pollution as the major factor driving resistance to insecticide.” Similarly, Seidahmed et al. observed

— Urban gardens along the banks of the Niger River in Bamako, Mali —

different urban agriculture land use patterns between urban and peri-urban areas as well as differences in insecticide resistance.

These studies suggest that urban planners not only need to consider urban agriculture in land use planning but also need a strong working relationship with public health authorities. Both need to work on pesticide use issues. Green cities can be places that help feed their populations, but they can also be places that a strong focus on local land use can be used to prevent malaria.

Whether overnight stays in farming huts poses a risk of malaria infection is a question being asked by researchers in Laos. Daisuke Nonaka and colleagues determined that “staying overnight in farming huts was not associated with an increased risk of malaria infection in the setting where ITNs were widely used in farming huts.”

Net use was greater in the rainy reason than dry in both farm huts (95% vs 66%) and main residences (82% vs 86%), and there were fewer nets on average in huts in the dry (1.1) and rainy seasons (2.3). The average number in main residences decreased from 3.1 in the dry to 2.1 in the rainy seasons.  This implies some movement of both people and nets between residences and seasons.

Another interesting finding was that there was higher prevalence of malaria when 5 or more people shared a net. Though the findings do not specify whether these sharing practices vary by residence or season, one might suspect a bit more crowding in the farm huts, and this should be explored.

Ensuring adequate number of ITNs to achieve universal coverage when people have one residence is a big challenge. In fact most procurement estimates are based on population, not residences.  Are there enough nets to cover all sleeping spaces, even if this means extra nets for a family?

Researchers in Tanzania when net supplies were not as large as today found that, “The household’s location at the time of interview (whether at their farm or village homes) was associated with parasitemia, and those residing at their farms were more likely to be parasitemic than those at their village houses, all other things held constant.”

Likewise, we found that mobility between farm and town settlements affected availability and use of cloth filters to prevent guinea worm.  Absence from the farm settlement at the time of ivermectin distribution is an important factor that affects coverage in onchocerciasis prevention efforts.

Unlike bednets, cloth filters for guinea worm can be more easily carried from one residence to another, and ivermectin pills can be kept easily until a mobile villager comes back.  Bednets by themselves pose challenges of hanging in even one residence, but ultimately we need to address the challenge of matching bednet supplies with the fact that rural people can have more than one residence in order to eliminate the disease.

Today is Labor Day in the United States. This holiday was first celebrated in 1882 with a parade in New York. Many countries observe a similar holiday on May 1st.  Regardless of the date, we should always consider the impact of malaria on the labor force of endemic countries and the subsequent economic impact of the disease.

For example, in Vietnam, Morel and colleagues conclude that, “Whilst government provision of malaria treatment keeps the direct costs relatively low, the overall loss in income due to illness can still be significant given the poverty amongst this population, especially when multiple cases of malaria occur annually within the same household.” The article goes on to document the cost in terms of loss of household productive workdays.

In India, Kumar and colleagues documented that, “The maximum DALYs lost (53.25%) were in the middle productive ages from 15 to 44 years of age, followed by children < 14 years of age (27.68%), and 19% in those > 45 years of age.” They continue by describing efforts to calculate the economic burden of the disease over the past 75 years.

A study of Ethiopian farmers who reported a malaria-like illness “stayed in bed for a mean duration of 7.8 days. Suspected, in this rural population, is a cycle of malnutrition, disease, and activity restriction that begins in childhood. Needed are interventions that reduce the prevalence of childhood stunting and health services that provide adequate prevention and treatment of diseases such as malaria.”

There is hope for workers. O’Meara et al. report, “substantial, lasting declines linked to scale-up of specific interventions,” in southern African countries. Countries in the Horn of Africa have also, “experienced substantial decreases in the burden of malaria linked to the introduction of malaria control measures.” In other countries the switch to ACTs after chloroquine began to fail, “led to immediate improvements; in others malaria reduction seemed to be associated with the scale-up of insecticide-treated bednets and indoor residual spraying.”

Will elimination of malaria lift endemic countries out of poverty? To find out, we need to achieve universal coverage and maintain a high level of intervention.

(see updated Ghana Advocacy News)

While there have been some doubts that climate change will cause more malaria, there is little doubt expressed that deforestation is one of the major contributors to the malaria problem.  Actually a link is found between deforestation and malaria.

Yasuoka and Levins looked at anophelene ecology changes in relation to deforestation. They learned that, “Although niche width of anopheline species was not associated with density changes, sun preference was significantly associated with an increase in density. This study suggests the possibility of predicting potential impacts of future deforestation on vector density by using information on types of planned agricultural development and the ecology of local anopheline species.”

Their review of reports from across the malaria-endemic parts of the would found that although the mechanisms that link malaria and deforestation are complex, there were clearly examples of direct effects on some anopheline species either because of habitat changes or because of land use changes, particularly agriculture.

Vittor and colleagues have recently examined deforestation and malaria in the Peruvian Amazon.  Their study concluded that, “Multivariate analysis identified seasonality, algae, water body size, presence of human populations, and the amount of forest and secondary growth as significant determinants of A. darlingi presence. We conclude that deforestation and associated ecologic alterations are conducive to A. darlingi larval presence, and thereby increase malaria risk.”

Ultimately the elimination of malaria will require our links with broader development and environment partners.

The fate of artemisinin in malaria control may be affected from the plant source to the parasites in humans according to two recent web postings.  Some challenges may result from people willing to change quickly, while others may be slow to react.

Sociolingo Africa has provided an update on artemisinin production in Uganda.  The situation of decreasing prices amid increasing demand was seen as puzzling.  The farmers who had begun cash crop production of artemisinin were now seeing ‘leaves rotting in the fields’ and were being encouraged to grow “Davana; Chillies; Fennel; Jasmine Rose; Ginger; Vettiver; Basil; and many more others, most of which are used in the production of essential oils and perfumes” by the Indian companies that were in fact guiding the Ugandan production of artemisinin.

It is possible, considering any commodity market, that diversification is a wise move on the part of the company.  Clearly there are efforts afoot (e.g. AMFm, Clinton Foundation) to reduce to cost that consumers pay in order to make the artemisinin-based combination therapy (ACT) drugs available thus, creating possibly more downward pressure on pricing.

In the early days of ACT promotion prices of the drug were said to be high because of the uncertainties in the procurement processes of endemic countries.  International mechanisms by organizations such as the Global Fund and WHO to coordinate this process while also increasing the supply to reach coverage targets also mean that production could confidently increase while prices of the final product could reduce.

So back to Uganda – there is likely now greater competition among producers of artemisinin in many countries – including the Ugandan farmers – in line with increasing demand projections. These farmers changed in reponse to the companies’ projections. At least in this case if substitute crops are provided, they may not suffer too much, but the fate of such farmers in other endemic countries such as Kenya where artemisinin farming has been introduced may not be so clear.

On the other side of the continent there are worries about parasite resistance to artemisinin.  In Nigeria ASNS News notes that, “Dr. Paul Orhi, Director General of NAFDAC (National Agency for Food and Drug Administration and Control), is quoted in the local press that the main reason for (growing emergence of resistance) was because people were not taking proper doses and that they still use monotherapy instead of combining two drugs appropriately.”

While it may take time for the resistance to spread from Southeast Asia where it has recently been documented, the Nigerian concern is real.  The irony is that there does not need to be worry about monotherapy if NAFDAC were to be bold and withdraw the registration of the numerous artesunate monotherapies currently on the market in Nigeria.

The current policy of NAFDAC is to allow those monotherapy drugs already registered to stay on the market until their registrations expire – some as late as 2012.  If NAFDAC were bold enough to change now and withdraw those registrations, its Director General would have less to worry about.  Proper training of health and pharmacy workers in both public, private and commercial sectors to counsel those receiving ACTs on the proper regimen would also reduce his worry about improper dosing.

Timely and appropriate change is needed to protect and increase the malaria drug supplies we have now, while research continues to find new medicines as the need will most certainly arise.

This morning the Daily Monitor of Uganda reported that, “At least 30,000 farmers in the districts of Kabale, Kisoro and Ntungamo who are growers of a medicinal plant that is a raw material for anti-malaria drugs are angry that the company that urged them to grow the plant has closed shop leaving them counting losses.” The artemisinin extracted from these leaves is the base for the current recommended first-line treatment of malaria – artemisinin-based combination therapy (ACTs).

It certainly seemed like a good idea in theory to grow A. annua in endemic countries and involve local farmers and the pharmaceutical industry in ACT production and at the same time promote economic development. But as the Daily Monitor shows, this can be a complicated process.  The leaves need to be harvested at just the right time to get the maximum concentration of the antimalarial drug.  The company complained to the Monitor that they were disappointed with their farmers who adulterated the quality:“Most of our farmers harvested Artemisia leaves before they matured. This lowered the artemisinin content.”

IRIN News explained that “In Kenya, the project is being spearheaded by East African Botanicals, which provides seedlings and supports both large- and small-scale farmers in a bid to rapidly increase the volume of plants.” The company spokesperson described their operations thus –

“By the end of 2005, we will have an estimated 1,200 hectares of the crop growing in Kenya,” explained a representative from the company. “We are also growing in Tanzania and Uganda, but still we cannot meet the demand. I am not able to overstate the shortage of this raw material worldwide. What we are growing is definitely making an impact on the shortage but not on the scale needed at the moment. “Everything we are doing is towards a very rapid scale-up of production: contracting more large- and small-scale farmers; planting more hectares; and finding ways to harvest the crop much faster,” he said.

IRIN also reports on efforts in Indonesia to grow A. annua. A government spokeswoman said, “farmers in Tawangmangu, where the soil was suitable for artemisia annua, traditionally grew vegetables and needed assurances that switching to the herb would bring them more benefit.  She expected Indonesia would be able to produce its own Artemisinin by 2010.” One hopes that these farmers will not be left without food crops or artemisinin profits like their Ugandan counterparts.

To make local production of Artemesia annua work there needs to be planning and coordination among government agencies, farmers, and the pharmaceutical industry. Botanical Extracts EPZ Limited in Kenya does claim to be making a profit from locally grown artemisinin, and so it should be possible for all partners to come together for success. The role of agriculture extension in educating farmers and helping them develop a safety net when A. annua crops fail is essential.

Finally, as we have stressed before, we hope that the eventual production of artemisinin synthetically or through biological processes will not render these farmers’ efforts useless.

Malaria control rests heavily on support from or activities of other development sectors besides health.  Power supply and agriculture provide two current examples.

Yewhalaw and colleagues explore the ramifications of dam construction for electricity supply in Ethiopia and see how human activity can increase mosquito breeding and the spread of malaria. Their work concludes –

This study indicates that children living in close proximity to a man-made reservoir in Ethiopia are at higher risk of malaria compared to those living farther away. It is recommended that sound prevention and control programme be designed and implemented around the reservoir to reduce the prevalence of malaria. In this respect, in localities near large dams, health impact assessment through periodic survey of potential vectors and periodic medical screening is warranted. Moreover, strategies to mitigate predicted negative health outcomes should be integral parts in the preparation, construction and operational phases of future water resource development and management projects.

At the same time Médecins Sans Frontières (MSF) has issued a warning about how agricultural market dynamics may have negative bearing on artemisinin supplies in the very near future. MSF explain that –

Current best estimates, based on available stocks and current planting efforts, demonstrate that there will be a shortfall of about 40 tons of artesiminin starting material in 2010 to produce the expected 240 million treatments needed. Taking into account that it takes about 14 months from the planting of Artemisia annua to the availability of the finished product, the availability in 2010 depends on what is being planted by farmers in the next weeks and months. We believe that market forces will not resolve the short-term artemisinin supply problem. Because it is extracted from plants, the supply of artemisinin is impacted by the highly volatile market of food crops which affect farmers’ decisions of whether or not to plant Artemisia annua.

These are two examples of how human actions exacerbate the scourge of malaria.  Such human influences are common throughout the history of malaria control. Intersectoral planning and surveillance is needed since malaria is not just a health affair.

The growing problem of urban hunger and urban food insecurity was featured in the Wall Street Journal today. In Monrovia, Liberia, “The cost of a cup of rice has risen to nearly 50 cents from 20 cents, a huge leap for many families who live on less than $1 per day.” The result: “Escalating hunger in African cities is forcing aid agencies accustomed to tackling food shortages in rural areas to scramble for strategies to address the more complex hunger problems in sprawling slums.”

One of these strategies, according to IDRC is urban agriculture:

Urban agriculture (UA) is wrongly considered an oxymoron. Despite its critical role in producing food for city dwellers around the world, urban food production has largely been ignored by scholars and agricultural planners; government officials and policymakers at best dismiss the activity as peripheral and at worst burn crops and evict farmers, claiming that urban farms are not only unsightly but also promote pollution and illness. Contradicting this image, recent studies document the commercial value of food produced in the urban area while underscoring the importance of urban farming as a survival strategy among the urban poor, especially women heads of households.

Urban farming requires water. The International Water Management Institute reports that, “Manual water fetching with watering cans is most common.” They often get water from “polluted streams or they do farming along storm water drains and gutters.” This sometimes leads to “wastewater irrigation.”

Of course malaria vectors need water. In urban Accra, Ghana, Klinkenberg and collaegues found that Anopheles and Culex “outdoor biting rates were respectively three and four times higher in areas around agricultural sites (UA) than in areas far from agriculture.”

The solution to the problem of urban malaria is not to stop urban agriculture, but to intensify integrated vector management interventions.  We certainly don’t want to protect people from malaria and then have then suffer from food insecurity.

Malaria “vectorial capacity was estimated to be 77.7% higher in the deforested site than in the forested site” in western Kenya according to a new study by Afrane and colleagues. Deforestation created micro-climates and micro-habitats. They concluded that “deforestation in the western Kenyan highlands could potentially increase malaria risk,” and unfortunately, “In African highlands where temperature is an important driving factor for malaria and the human population generally has little functional immunity.”

Generally, “Kenya’s forests are rapidly declining due to pressure from increased population and other land uses,” as explained by the World Rainforest Movement (WFM). The process has been long standing from including early establishment of large agricultural plantations in the last Century to continued agricultural expansion based on population growth and logging. WFM advocates for community involvement in forest conservation.

Kenya is making progress on reducing malaria deaths through successful LLIN and treatment efforts, but this may be offset if communities do not see the connection between malaria and their environment.  Intersectoral collaboration in malaria control is crucial so that gains in malaria intervention coverage are not counteracted through expanding endemic areas.

Nine companies engaged in organic farming in Lango sub-region’s districts of Oyam, Apac and Lira are suing the government of Uganda over the use of DDT for indoor residual spraying according to the Monitor. The Monitor reports the case as filed states that, “The decision by the government to introduce DDT in the districts is illegal as it contravenes the provisions of the Stockholm Convention on persistent organic pollutants of 2001.” WHO does clarify that the Convention says DDT can be used for public health purposes, but the question is, who defines the public’s health?

The farmers have logical fear that if DDT spraying inside houses is not done with proper precautions, their crops and livelihoods as organic farmers could be imperiled. Those pressing the suit claim that the agency contracted to do the work is in fact not following precautions and thus opening the potential to contaminate their crops. Let’s look at what is at stake.

In an overview of organic farming in Uganda, the International Trade Center explains that, “Uganda has the most developed sector of certified organic production in Africa. About 33,900 farmers manage 122,000 hectares of land using organic methods, an area that accounts for 1% of Uganda’s arable land (IFOAM & FiBL, 2006). Although still small and far below the increasing global demand, the country’s export of organic agricultural produce has been growing substantially in recent years. In Uganda, which has one of the lowest agro-chemical usages in Africa, the majority of farmers practice de facto organic agriculture without being certified yet (ACODE, 2006). Since no significant domestic market exists, certified organic agriculture targets mainly export markets in Europe and North America.”

In fact, the Monitor reported in 2007 that, “Organic farming has become a means of generating income for farmers and consequently fighting poverty.” Furthermore, “On the world market, Uganda’s export share of organic products has increased considerably and is the highest in Africa. The coordinator of Nogamu, Mr Moses Muwanga says 38 percent of organic agricultural production in Africa is from Uganda, with over 50,000 certified organic farmers. This makes Uganda one of the countries with the highest comparative advantage for organic production in Africa.”

Tiki-OneWorld.net takes us to an organic farm in Tororo District and with pictures and text concludes that a Tororo farmer could, “teach farmers in Europe or America a thing or two. His type of farming — sustainable and organic — produces lots of food and lots of varieties of food. And it doesn’t need huge tractors, diesel fuel, artificial fertilisers and chemical poisons. As I said earlier, nothing is wasted.”

The Kulika Charitable Trust Uganda “has set up a sh800 million agricultural training institute at Lutisi, 37km on the Kampala-Hoima highway,” (AllAfrica.com). In short, there have been major investments in capacity building for organic farming in Uganda. “The core of Kulika’s Community Development Programme is training of farmers in sustainable organic agriculture which focuses on experiential learning, practical work, on-farm experimentation and demonstrations to improve the skills of farmers (see photo from Kulika).”

The economic issue here may be confusing – a chicken and egg debate. Does malaria control promote economic development or does economic development strengthen societies to control malaria. Assuming it is the latter scenario, we need to think twice about interventions that will affect the livelihoods of thousands of Ugandan farmers, specially when alternative control measures are available.

WHO recognizes that, “When implementing IRS, it is critical to ensure that adequate regulatory control is in place to prevent unauthorized and un-recommended use of public health pesticides in agriculture, and thus contamination of agricultural products. Pesticide contamination can have serious ramifications for trade and commerce for countries exporting agricultural products.” The organic farmers in Uganda question whether adequate control is possible.