Tropical Health Matters

The World Health Organization is guiding countries across the Sahel of Africa to begin piloting ‘seasonal malaria chemoprevention” or SMC. We recently featured this in the May 2013 issue of Africa Health. WHO explains that “Seasonal malaria chemoprevention is defined as the intermittent administration of full treatment courses of an antimalarial medicine to children during the malaria season in areas of highly seasonal transmission.” This is an outgrowth of several years of research into intermittent preventive treatment for infants (IPTi) and children.

Malaria program managers wanted a more focused application of IPTi where it would be likely to make a major impact on disease control. Researchers found that areas meeting malaria seasonality definition of 60% of annual incidence within 4 consecutive months were observed more frequently in the Sahel and sub-Sahel than in other parts of Africa, and thus could provide an ideal focus for intervention.

What makes transmission more intense in those four months is the rainy season.  Ironically we have recently seen a more intense rainy season in the Sahel with serious flooding. IRIN reports that, “The African Centre of Meteorological Applications for Development (ACMAD) in a seasonal weather outlook says near-average or above-average rainfall is likely over the western Sahel, which stretches across Mauritania, Senegal and western and central Niger. These regions are ‘expected to be the area with the highest risk of above average number of extreme precipitating events that may lead to flash floods’.”

What does this flooding mean for SMC?  While breeding mosquitoes obviously need the pools that rainwater creates, too much rain may have an opposite effect with flash floods washing out breeding sites (let alone homes and possessions). When flooding results in larger and longer collections of standing water, mosquito breeding may be enhanced, but this will make logistical support for training, supervision, and drug supplies extremely difficult in the region.

The Sahel is one of the areas in Africa where we might hope for some early progress toward malaria elimination. With global climate changes affecting the region we can only wonder whether the weather will cooperate and allow timely implementation of new interventions.  As IRIN implies – contingency planning is extremely important.

Clearly no one wants to argue against efforts to curb a deadly disease. The question is whether the approaches to doing so have any negative consequences that can be easily ameliorated.

Vector control gets the most attention. One concern is the plastic bagging in which long-lasting insecticide treated nets are packaged. Rwanda, which has outlawed commercial use of plastic bags for shopping, is taking the LLIN packaging seriously.  The photo shows net packaging that has been removed at a health center and stored for later incineration. Clients take their nets home in paper bags and are encouraged to hang them immediately.

Another net concern is disposal of old, used, damaged nets. LLINs do not have under ‘normal’ conditions the 5-year lifespan originally hoped. Plans for proper disposal are not fully developed in most settings, but the massive distribution of nets to achieve universal coverage from about 2009-12 are about to need replacement. It is possible that some of the net misuse reported in the media is actually repurposing of old nets. More information from communities and local health authorities is needed.

Insecticides for indoor residual spraying usually are the first thought that comes to mind concerning environmental impact of malaria control. While arguments primarily focus on DDT, it is important to note that WHO has approved over a dozen different insecticides for IRS.  The problem is not so much the use of chemicals for actual IRS, but the misuse outside approved spraying programs for farms and fish kills. At present IRS is a highly geographically focused activity in most countries, and control of the activities seems to be working for the large part, but even the process of preparing for and cleaning up after a spraying exercise can results in spills and contamination. Guidelines exist, but are they followed?

Then we get to the issue of medical waste from rapid diagnostic tests.  Some health centers sharps and waste boxes for short term disposal and as pictured here in Burkina Faso, have incinerators tor final disposal.  Community health worker use of RDTs is usually accompanied by sharps and disposal boxes that can be returned to health centers.  All of this needs careful monitoring.

One must even think about packaging of artemisinin-based combination therapy medicines which are prepackaged by age group. These packets are small and are sent home with patients and care-givers. The paper may be burned or composted, but there are also plastic blisters in the packet. This may not account for much on an individual family basis, but on the community level it may be substantial.

Readers may think of other environmental concerns from their own experiences and share success stories for environmental management accompanying malaria control in their countries.  So, as noted, we will not stop malaria control efforts on Earth Day, but at least we can be more conscious of the materials used, whether they can naturally decompose in the environment and thus make some contribution to a healthier planet.

The APHA schedule search turned up 31 presentations, panels and posters related to malaria. If you are attending the American Public Health Assocation 140th annual meeting, take advantage of these.

1.    Barriers to practicing healthy behaviors for malaria prevention and child nutrition in Zambia: A qualitative study 263984 Barriers to practicing healthy behaviors for malaria prevention and child nutrition in Zambia: A qualitative study Wednesday, October 31, 2012 Lovemore Mwanza , Research, Monitoring, and Evaluation …

2.    Prevalence of Malaria in Pregnancy as Rwanda Moves towards Malaria Elimination
265783 Prevalence of Malaria in Pregnancy as Rwanda Moves towards Malaria Elimination Tuesday, October 30, 2012 : 3:00 PM – 3:15 PM Corine Karema …

3.    Malaria diagnosis: Perspectives from caregivers and health staff, Makarfi, Nigeria 261566 Malaria diagnosis: Perspectives from caregivers and health staff, Makarfi, Nigeria Tuesday, October 30, 2012 : 8:35 AM – 8:50 AM Olufemi …

4.    Impact of climate and land use influencing the spatial and temporal distribution of malaria risk in the Amazon 261531 Impact of climate and land use influencing the spatial and temporal distribution of malaria risk in the Amazon Tuesday, October 30, 2012 Beth J. Feingold, PhD, MESc, MPH , Department of Earth and Planetary …

5.    Measuring Malaria Advocacy Outcomes 270759 Measuring MalariaAdvocacy Outcomes Monday, October 29, 2012 : 11:30 AM – 11:45 AM Marc Boulay, PhD , Center for Communication Programs, …

6.    How can we Accelerate Programming for Malaria in Pregnancy? 274603 How can we Accelerate Programming for Malaria in Pregnancy? Monday, October 29, 2012 : 11:30 AM – 11:50 AM William R. Brieger, MPH, CHES, DrPH , Jhpiego, …

7.    Improper maternity wear, mean providers, and vomiting: Barriers to timely IPTp uptake for malaria prevention during pregnancy in rural Zambia 266032 Improper maternity wear, mean providers, and vomiting: Barriers to timely IPTp uptake for malaria prevention during pregnancy in rural Zambia Tuesday, October 30, 2012 : 3:15 PM – 3:30 PM Hilary Schwandt, PhD, MHS …

8.    How local government health workers in Nigeria manage suspected malaria cases 265691 How local government health workers in Nigeria manage suspected malaria cases Tuesday, October 30, 2012 : 2:45 PM – 3:00 PM Bright Orji, MPH , Nigeria, Jhpiego, Baltimore, MD William …

9.    Challenges of implementing intermittent preventive treatment in Zambia for malaria prevention in pregnancy 263075 Challenges of implementing intermittent preventive treatment in Zambia for malaria prevention in pregnancy Tuesday, October 30, 2012 : 2:30 PM – 2:45 PM Peter Mumba, MD, MSc , Zambia Integrated …

10.    Contemporary Issues in Malaria in Pregnancy: Why worry now? 274600 Contemporary Issues in Malaria in Pregnancy: Why worry now? Monday, October 29, 2012 : 10:30 AM – 10:50 AM Mary Nell Wegner, EdM, MPH …

11.    Community-based Interventions for Malaria in Pregnancy: Findings from Mozambique 274602 Community-based Interventions forMalaria in Pregnancy: Findings from Mozambique Monday, October 29, 2012 : 11:10 AM – 11:30 AM Leonardo Chavane, MD, MPH , …

12.    Spatial access to malaria treatment in Kenya and its impact on health seeking behavior: A GIS based study 270764 Spatial access to malaria treatment in Kenya and its impact on health seeking behavior: A GIS based study Monday, October 29, 2012 Brittany Goettsch, …

13.    Challenges of Addressing Malaria in Pregnancy through Antenatal Care Services: A Nigerian perspective 274601 Challenges of Addressing Malaria in Pregnancy through Antenatal Care Services: A Nigerian perspective Monday, October 29, 2012 : 10:50 AM – 11:10 AM Oladosu …

14.    Invited Panel: Malaria in Pregnancy: An urgent yet solvable problem uniting the maternal health and malaria communities in Africa 3150.0 Invited Panel: Malaria in Pregnancy: An urgent yet solvable problem uniting the maternal health andmalaria communities in Africa Monday, October 29, 2012: …

15.    Malaria & Vector-Borne Diseases 4320.0 Malaria & Vector-Borne Diseases Tuesday, October 30, 2012: 2:30 PM – 4:00 PM Oral Moderator: Pablo Aguilar, MD MHSc 2:30pm Challenges of implementing …

16.    Poster Session: Nutrition … 2012: 8:30 AM – 9:30 AM Poster Organizer: Mike S. Bailey, MA / Co-Chair Board 1 Barriers to practicing healthy behaviors for malaria prevention and child nutrition in Zambia: A qualitative study Lovemore Mwanza, Rikki Welch, MA, John Manda, Samantha Herrera, Ana Claudia …

17.    *Poster Session*: Emerging issues in environmental public health … MCP and Devon Payne-Sturges, DrPH Board 4 Impact of climate and land use influencing the spatial and temporal distribution of malaria risk in the Amazon Beth J. Feingold, PhD, MESc, MPH, Benjamin Zaitchik, PhD, Victoria Shelus, BSc and William Kuang-Yao Pan, …

18.    Innovation in Technology: Public Health Models Posters 2 … practices serving underserved communities Kristina Vasileva, MPH, Mandy Smith Ryan, PhD and Mariceli Comellas, MA Board 10 Spatial access to malaria treatment in Kenya and its impact on health seeking behavior: A GIS based study Brittany Goettsch, MPH Candiate See individual …

19.    Infectious Disease Epidemiology 2 … AM – 10:00 AM Oral This session will provide new findings in the area of infectious disease epidemiology including the areas of malaria, TB, and influenza. Session Objectives: Assess the adequacy of zip code tabulation areas as a proxy for census tracts when …

20.    Advocacy & Global Health … Kovach, MPH, A. Elisabeth Sommerfelt, MD, MS, Alice Nkoroi, MS, Robert Mwadime, PhD and Ferdousi Begum, MBBS, MS 11:30am Measuring Malaria Advocacy Outcomes Marc Boulay, PhD, Claudia Vondrasek, MPH, Matt Lynch, PhD and Sarah Dalglish, MPH See individual abstracts for presenting …

21.    Seeing the obscured: A social epidemiological assessment of malaria’s reemergence in deforested regions 269174 Seeing the obscured: A social epidemiological assessment of malaria’s reemergence in deforested regions Tuesday, October 30, 2012 Beth Phillips, MPH , Mel and Enid Zuckerman College of Public Health, …

22.    Factors associated with completion of Intermittent Preventative Therapy (IPT) among pregnant women in Malawi … Sciences for Health, Arlington, VA Allison Zakaliya , Baylor Children’s Foundation, Baylor Children’s Foundation, Lilongwe, Malawi Misheck Luhanga , National Malaria Control Program, Ministry of Health, Lilongwe, Malawi Johnes Moyenda , Mpemba Health center, Ministry of Health, Blantyre, Malawi Doreen Ali…

23.    Designing a translational epidemiologic study: Chloroquine and breast cancer chemoprevention in Returned Peace Corps Volunteers … present the design of a novel translational epidemiologic approach to confirm preclinical data on the chemopreventive potential of a well-characterized anti-malarial drug. BACKGROUND: Exposure to chloroquine, an off-patent anti-malarial drug with a 60-year history of use by millions, reduces the incidence…

24.    Exploratory assessment of alternative use of bed nets within the Arisi zone in Ethiopia: Findings from household interviews and observations … Thaddeus Pennas, MS , C-Change, FHI360, Washington, DC Background: Distribution of long lasting insecticide-treated nets (LLINs) is one of four malariaprevention interventions being scaled up in sub-Saharan Africa. Correct and consistent use of LLINs by households is central to the …

25.    Young and vulnerable: Comparing delivery care, domestic violence, and child undernutrition between adolescent girls and women in Bangladesh … and Asia on topics related to evidence-based advocacy to improve nutrition, reduce maternal mortality, increase newborn survival, and decrease the malariaburden; written on child health and nutrition; and domestic violence against women. Carried out the data assessment and analyses. Have …

26.    Determinants of insecticide treated bednet (ITN) use by households in Nigeria … tying ITN to nails on the wall, and frequent washing of the ITN. The number of times a child had malaria in past 6 months, where child slept at night, and use of other malaria control measures were also associated with …

27.    Measuring the competencies and skills of midwives in an accelerated training program in Zambia … 25% felt they were not competent to treat patients with pneumonia while only 2% felt incompetent to manage patients with malaria; neither were statistically associated with duration of service (X2=61539;2=3.163, p=0.075; X2=61539;2=0.002, p=0.962 respectively). Conclusions: The assessment showed that the certified …

28.    Community Health Workers and Prevention: How to measure effectiveness of preventive community health programs centered on CHW … effectiveness of their preventive messages and adapt them for maximum results. With an effective tool to measure the effectiveness of malaria and HIV prevention and messages on hand washing and adequate nutrition, CHW receive immediate feedback on the challenges their communities …

29.    Improving access to preventive healthcare in Haiti: A community based approach … under five years of age, prevention messages delivered through skits, micronutrient supplementation, mosquito nets to pregnant women to help preventMalaria in Pregnancy, and blood pressure checks for all. Preliminary data have shown increased uptake of services and better maternal and …

30.    Mobile technology-based approach for facilitating health data collection, sharing, analysis and use in Uganda … of health centers through UHIN including monthly HMIS reports, disease surveillance data, and specific reports related to HIV/AIDS, TB, and malaria. Rural hospitals use UHIN for capturing data on electronic daily registers such as PMTCT, in-patient, lab, HIV counseling, and ART …

31.    Climate change and blood safety … transmission of dengue fever occurred in France in 2010. Other infectious agents are of concern such as Hanta virus, leishmaniasis, malaria, tick-borne encephalitis and their relationship to climate change and blood safety will be discussed. These insights call for changes in …

Recently Matt Lynch of the Johns Hopkins Center for Communications Programs and the USAID NetWorks Project was asked about the challenges of disposing old ITNs. His response has been shared on Malaria Update, but we thought readers on Malaria Matters, who are not Update subscribers, could also learn from Matt’s Ideas. Matt urges that each country and community needs to find its own economic and ecological solutions as seen below.

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I would urge a careful look at all the options (including leaving the nets in the households) before leaping into actions which may end up with worse consequences than no action at all.

Much that I have heard on this topic begins with the assumption that nets must be collected – this is not necessarily true, and no one has been able to adequately describe to me exactly what the problem of leaving the used nets for households to re-purpose might be.  They are, on the other hand, very ready to describe the massive costs associated with collecting the nets, and the problems which will follow from concentrating enough old nets in one spot to actually have insecticide and plastic concentrations which do become quantifiable problems.

As far as I can tell from asking the manufacturers, most pyrethroids decay when exposed to UV light, and are broken down by soil bacteria.  This is why pyrethroids are so popular in agriculture – they don’t persist in the environment.  They are apparently quite toxic to fish, so that’s worth exploring in the island environments.  Dumping them into the sea is probably not a great idea.

In Africa, one frequently sees old, holed nets being used to cover plants, chicken coops, or to screen windows.  Such uses, as far as I can tell, do no harm and probably some good (who knows, the residual insecticide may help control chicken mites?).  In addition, they provide an opportunity for the UV light and soil bacteria to begin breaking down the insecticides.

One might expect polyethylene nets to pose more of a problem in terms of solid waste, but I have not seen any reports of drains being blocked by old bednets (plastic bags, frequently!).  Polyester nets are even more difficult to imagine as a serious solid waste problem – after all, there were millions of pretty toxic-looking polyester leisure suits sold in Africa through the 1980’s and no one seems concerned about their disposal…

So, I don’t mean to trivialize the issue;  I think we need a clear description of precisely what the problem is with letting households dispose of their worn-out nets through their usual practices.  There may well be harmful disposal practices that need to be addressed, but I do think we need a clear description of the problem before we rush into complicated, expensive and potentially hazardous “solutions”.   I personally doubt the optimal solution will be to collect the nets.

Models represent reality but the closer they come to reality, they better they are at helping us plan.  A session at the American Society of Tropical Medicine and Hygiene yesterday addressed the modeling process for vector control.

VECNet is developing the capacity to take data from multiple sources to tailor vector populations and behavior to local situations. Such models need to consider vector bionomics/population variables, weather/climate/environment, and effectiveness of deployed vector control strategies.

Modelers encourage us to think beyond existing malaria control strategies and consider a varierty of mosquitoe behaviors beyond direct feeding on humans and immediate resting thereafter. Such understandings can lead us to ask whether new interventions could be directed at other vector bevahiors such as …

• laying eggs (oviposition)
• feeding on sugars
• seeking hosts
• mating
• resting generally

In short, we were challenged to look at aspects of vector biology that have been ignored or unknown in the past.

The MAP project out of Oxford is also beginning detailed mapping of vectors by region and utlimately my country.  Globally there are 41 dominant vector species, so the work ahead is immense, but some mapping has started with three in a program called Risk Mapper.

The session also included product impact estimation. This should help program planners decide on hypothetical outcomes of investments in different existing interventions and even consider possible outcomes were new interventions developed to address the other aspects of mosquito behavior outlined above – e.g. traps, repellents.

The modeling process requires a lot of data that needs to be updated as control interventions proceed. Such data requires a strong corps of entomologists and health information systems staff that many countries lack.  Hopefully modeling efforts will also include these elements of human resource development.

Human activity is leading to deforestation in central Africa and bringing hunters and people in closer contact with our primate cousins and their collection of pathogens.  The Global Viral Forecasting Initiative is carefully studying these contacts between humans and other vertebrates in an effort to identify possible new viral epidemics. In the process they have also made observations about the origins of human malaria and the potential for transmission of primate plasmodium infections to people.

While transmission of malaria species between humans and other primates has been documented in South America and Africa, Southeast Asia has received the most attention.  In fact, the question is being raised as to whether P. knowlesi is becoming the fifth human malaria parasite. If new infections as well as new species are arising from the primate world, this has grave implications for efforts to eliminate malaria worldwide.

A recent study from Vietnam found that, “showed P. knowlesi infections in 32 (26%) persons with malaria (n = 125) and in 31 (43%) sporozoite-positive An. dirus mosquitoes (n = 73). The authors observed and warned that …

P. knowlesi–co-infected patients were largely asymptomatic and were concentrated among ethnic minority families who commonly spend nights in the forest. P. knowlesi carriers were significantly younger than those infected with other malaria parasite species. These results imply that even if human malaria could be eliminated, forests that harbor An. dirus mosquitoes and macaque monkeys will remain a reservoir for the zoonotic transmission of P. knowlesi.

In another study researchers confirmed P. knowlesi in humans in Cambodia. This is worrisome especially since Cambodia is one of the locations where resistance to artemisinin-based medicines is rising.

Likewise, researchers in Malaysia reported that, “P. knowlesi is a major cause of severe and fatal malaria in Sabah. Artemisinin derivatives rapidly clear parasitemia and are efficacious in treating uncomplicated and severe knowlesi malaria.”  Gametocytes of P. knowlesi in a Giemsa-stained thin blood smear from a patient that traveled to the Philippines can be seen in the attached photo from CDC.

Simian reservoirs of malaria throughout Southeast Asia pose a major challenge for control efforts.  Tackling this problem in the forest habitats where people come into contact with monkeys will be daunting – we are not out of the woods yet for malaria elimination.

We have posted news on the corporate social responsibility efforts of major gold mining companies in Ghana.  A supervisory visit to health facilities in the southern part of Burkina Faso yielded another perspective on gold mining and malaria.

Along the road one saw individuals engaged in mining by hand.  These persons had set up their own camps with ad hoc housing.  Local health workers were concerned about the potential for transmission of sexually transmitted diseases, but there are also malaria concerns.

The miners are essentially migrant workers.  It is questionable as such that they would have access to insecticide treated bednets.  As a non-indigenous population one also wonders about their access to appropriate malaria treatment services.

Finally there is concern that in the current rainy season whether the surface mining operations might have some impact on mosquito breeding sites.

Local ‘wildcat’ mining for gold in Zamfara State, Nigeria has had a devastating effect of poisoning local children.  It is not clear how such operations benefit the national or local economy, and clearly the health threats are numerous.  The malaria elimination environment is certainly complicated.

According to the BBC, “Reports from northern Nigeria say a growing number of people from Niger are crossing the border into Nigeria because of the food crisis at home. A BBC correspondent in the northern Nigerian state of Katsina says many women and children from Niger are seeking shelter with local families.” Although Niger has experienced droughts and famine before, such events are expected to become more frequent as the globe warms.

A recent article by Peter Gething and colleagues has basically sought to de-link the notion that climate change is synonymous with increased malaria transmission, and the Niger example may be a case in point. While there have been examples of warming leading to increased malaria transmission in the East African highlands, analysis by Gething’s group shows that overall, human efforts through recent massive control interventions are more of a factor in influencing a downward trend, than climate change could push transmission upwards.

A drier environment that produces these famines is also less conducive to mosquitoes and malaria transmission. This, of course, is not the type of trade off one wishes in order to achieve malaria control targets.

The question of greater interest is whether the global community will continue to fund malaria control efforts and increase that funding so that climate change or any other factor will not stand in the way of malaria elimination?

Johan Rockström and colleagues address the question of economic growth and its impact on climate change and the environmental tipping points beyond which life as we know it may no longer be possible. If we move to a no growth scenario, will there still be funding to fight the major killer diseases? Will we put the breaks on climate change and yet forfeit progress on malaria control due to lack of funding?

Much depends on our priorities. Are we willing to stand up for a world that is saved from the environmental degradation caused by unlimited growth as well as one that is free from malaria?

World Malaria Day comes close on the heels of Earth Day (today), though the latter has been celebrated for about 30 years longer.  Malaria Day, April 25th, is near the beginning of the rainy and malaria season in the northern hemisphere, and rains – not enough or too much – are a major environmental concern on Earth Day. In short malaria is vitally linked with the environment. Here is a sampling of how various web sites see the connection.

A striking poster entitled “Stop Global Warming” by Professor Yoon of Seoul, Korea teaches environmental art. The global warming poster is by one of his students depicts a child at risk of malaria composed of many tiny mosquitoes.

Paul Chesser reviews the interrelated issues of malaria control and environmental effects of pesticides, particularly DDT. The benefits accrued through focused use of the chemical in industrialized countries with strong health systems. Aside from environmental concerns, spraying as a control tool did not succeed in poor countries where health systems could not sustain the effort on a broad basis.

We wonder whether 50 years later health systems in endemic countries are stronger, not only to ensure adequate spray coverage in appropriate locations, but also prevent ‘leakage’ into other sectors and misuse.

Cheryl Saban is an optimist. she suggests donating to malaria control efforts is the perfect Earth Day gift. “Malaria is an illness that can easily be eradicated — we have the knowledge of what to do – education, mosquito nets and medication, and the network of distribution is being worked out too.” We definitely need donations, though eradication may not be just around the corner.

The Earth Day web page reports on the Democratic Republic of Congo‘s National Biodiversity Strategy and Action Plan. This includes – “project for the restoration and rehabilitation of the national parks, plans for the protection and rehabilitation of endangered species and ecosystems, development of the Zoological and Botanical Institute of Congo, program to fight the vectors of malaria, National Program for sustainable agriculture and the National Strategy on Biosafety.”

The New York Times has observed that at 40 year old, Earth Day has become ‘big big business. “While the momentum for the first Earth Day came from the grass roots, many corporations say that it is often the business community that now leads the way in environmental innovation — and they want to get their customers interested.”

The malaria control/elimination effort has certainly attracted major supporters from the corporate world and entertainment industry. It has also benefited from the Product Red efforts to turn commercial instincts toward funds for HIV, TB and malaria control, but Malaria Day has yet to become so commercialized.

Hopefully Malaria Day will maintain its focus on practical ways to help solve a problem by all partners – corporate, NGO, government and average world citizens, but at the same time attract enough attention to fill the large funding gap that remains.

The recently concluded climate change summit on Copenhagen did not stress health, let alone malaria, as much as other consequences of climate change.  The Inter-governmental Panel on Climate Change has let us know a reason why attention to malaria in the climate debate may be somewhat confused:

Climate change may “have mixed effects on malaria; in some places the geographical range will contract, elsewhere the geographical range will expand and the transmission season may be changed.”

Kenya is one of those areas that has been reporting increases in the geographical range of malaria – particularly into the highlands.

Li and colleagues have been examining the Western Highlands over the period 2003-05 and documented variability of mosquito breeding sites by season and year.  Their findings point to ways to improve larval habitat modifications as an important part of integrated vector management in such areas of seasonal and focal mosquito breeding.

An integrated approach to malaria control also is credited for a “pronounced reduction and possible interruption of malaria transmission in 2 highland areas of Kenya for a 1-year period and provides evidence that interruption of transmission was related to widespread annual IRS insecticide treatment and use of ACT as first-line treatment for uncomplicated malaria. Although both areas remain at risk for recurrence of malaria epidemics, our study provides evidence that interruption and eventual elimination of malaria in areas of unstable transmission may be achievable.”

The Mount Kenya highlands have been studied by Chen et al. who were concerned about possible increases in malaria cases reported over the past 10-20 years there. They found that, “Local malaria transmission on the Mount Kenya highlands is possible due to the presence of An. arabiensis. Land use pattern and land cover might be the key factors affecting the vector population dynamics and the highland malaria transmission in the region.” Human factors appear to play an important role –

On the Mount Kenyan highlands, the population has increased at least 25% over the past 20 years. Population density in Karatina and Naro Moru areas is estimated at 530 persons per square km, much higher than those in the further north areas, e.g., only 81 persons per square km in Nanyuki. With the increasing population on the highlands, enhanced human activities including deforestation, farming and livestock rearing could create more vector habitats. For example, at the site northwest to Karatina, hundreds of anopheline larvae were found in ditches holding spring water for crops in a field. The vectors emerging from this kind of habitat can play an important role in local malaria transmission.

More recently researchers from the Kenya Medical Research Institute with support from DfID “found that the average temperature in the Kenyan Central Highlands had risen from 17C in 1989 to 19C today.” Specifically the group reported that …

Before the 1990s malaria was absent from the region because the parasite that causes it can mature only above 18C. However, malaria epidemics began among the population as average temperatures went over the 18C tipping point. The number of people contracting malaria during these epidemics has increased seven-fold in the past decade. In 2005, malaria-carrying anopheles mosquitoes were discovered in Naru Moro, more than 6,175ft (1,900m) above sea level.

Climate change may partly explain malaria increases in Kenya’s highlands, as may more local human activities. The important lesson is that such epidemic-prone areas need to be closely monitored. A timely mix of control interventions can then be judiciously applied. As Noor and colleagues recommend:

As malaria interventions go to scale effectively tracking epidemiological changes of risk demands a rigorous effort to document infection prevalence intime and space to remodel risks and redefine intervention priorities over the next 10-15 years .