Tropical Health Matters

Rwanda has been commended for progress made toward eliminating malaria. Just to the south, Burundi appears to be experiencing an upsurge of the disease. Can it be contained?

MSF reports that, “Burundi has been grappling with a serious increase of malaria patients since the start of the year. The MSF teams have been cooperating with Burundi authorities to fight the spread of the disease by treating patients and distributing mosquito nets to prevent new infections.”

Fortunately the Canadian Red Cross has been working in Burundi distributing bednets, but donor support for malaria control in Burundi has not kept up with that of Rwanda.
Rwanda with a population of 9.2 million, has benefited much more from international donor support. Rwanda is in its fifth year of funding from the US President’s Malaria Initiative  and has received Global Fund malaria grants three times of which $109.5 million has been disbursed and another $100 million is in the pipeline.
Burundi with a population of 7.8 million, has just begun to receive attention from USAID’s malaria efforts. Of a current $53 million Global Fund Malaria grant, Burundi has received $17 million. A new Round 9 grant for $60 million has yet to be signed.

Burundi’s Road Map to 2010 shows a gap of 2.5 million long lasting insecticide-treated nets, and nearly half a million doses of artemisinin-based combination therapy drugs. Rwanda has no gap in these commodities.

When moving toward malaria elimination, we need to plan on a regional basis, not just country by country. Neither infected mosquitoes more humans bearing malaria parasites respect borders. Countries may need to be their brother’s keeper in order to protect the gains they have made.

Fortunately the Southern African Development Community‘s malaria elimination strategy enshrines this philosophy of mutual help among neighbors.  Other regions should follow suit.

Cell phones are being used for more than calls and text messages.  A variety of applications to help treat and control malaria have been tested over the past few years. A few examples from Africa follow.

1. Diagnostics and Patient Monitoring

Gizmodo explained that, “Scientists at UCLA modded an ordinary phone into a portable blood analyzer that can detect diseases at a very low cost … Blood analysis usually requires either large and expensive equipment or a trained technician to manually examine the material. Both are out of reach for many remote areas, especially in parts of Africa where HIV and malaria are rampant.”

Indian Express notes that this, “Lensless Ultra-wide-field Cell monitoring Array platform based on Shadow imaging has now been successfully installed in both a cell phone and a webcam. Both devices acquire an image in the same way as using a short wavelength blue light to illuminate a blood, saliva or other fluid sample.”

Fletcher and colleagues determined that, “A telemedicine system for global healthcare via mobile phone – offering inexpensive brightfield and fluorescence microscopy integrated with automated image analysis – to provide an important tool for disease diagnosis and screening, particularly in the developing world and rural areas where laboratory facilities are scarce but mobile phone infrastructure is extensive.”

Global Envision explained that Fletcher’s team “has been able to reliably identify pathogens from two of the most prominent diseases in the underdeveloped world — malaria and tuberculosis.”

2. Surveillance and Program Monitoring

Cellular News reported that, “University of Florida researchers at work on a malaria elimination study in Africa have become the first to predict the spread of the disease using cell phone records.”

The study by Tatem et al., found that, “Anonymous mobile phone records provide valuable information on human movement patterns in areas that are typically data-sparse. Estimates of human movement patterns from Zanzibar to mainland Tanzania suggest that imported malaria risk from this group is heterogeneously distributed.”

In 2008, Unicef pioneered a new text message based system for data transmission called RapidSMS. It has been used recently in Nigeria to track distribution of ITNs during massive state-wide campaigns and in Malawi as part of an Integrated Nutrition and Food Security Surveillance System.

As Unicef observes, “Without accurate and timely data, it is very difficult to make decisions, see where there are problems, respond quickly, and allocate resources effectively. RapidSMS is a powerful suite of tools that directly address this problem improving coordination and impact.”

3. Health Communication

Unicef is also collaborating with local telecoms to spread the work about health programs. This past July, “To highlight Zambia’s Child Health Week activities, which this year focus on preventing polio, the Ministry of Health and UNICEF have joined together with two of the country’s leading mobile phone companies, ZAIN and MTN, to spread the message about vaccinations and other key intervention.”

Richard Lester and co-researchers are testing the applicability of cell phones to communicate with patients and improve compliance with anti-retroviral treatment. They hope to, “test the effectiveness of the described intervention protocol, but will instruct further development of the use of mobile telephony to improve health management in resource limited settings.”

While there are still a number of cost, coverage and regulatory issues to be addressed, cell phones are poised to become an invaluable technology for controlling malaria and saving lives.

Copenhagen is ready for the United Nations Climate Change Conference, which opens tomorrow for two weeks. Live webcasts and archived versions will enable people with adequate bandwidth to feel part of the deliberations. At present the main consequences of climate change that are attracting global attention include –

• More droughts and more flooding
• Less ice and snow
• More extreme weather incidents
• Rising sea level

These physical changes will have major social, political, economic and health consequences.  Implications for malaria specifically, require some interpretation. This is where reports of the Intergovernmental Panel on Climate Change may help.

Projected trends in climate-change-related exposures of importance to human health will 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.

The IPCC Report also acknowledges “the difficulty of generalizing health outcomes from one setting to another, when many diseases (such as malaria) have important local transmission dynamics that cannot easily be represented in simple relationships.” Examples of individual country assessments follow:

• Australia may see potential change in the geographical range of dengue and malaria
• Bolivia expects intensification of malaria and leishmaniasis transmission. Indigenous
  populations may be most affected by increases in infectious diseases
• Bhutan might experience spread of vector-borne diseases into higher elevations
• India projects that Malaria could to move to higher latitudes and altitudes

The IPCC report sees that drought would have a limiting effect on malaria.

In the long term, the incidence of mosquito-borne diseases such as malaria decreases because the mosquito vector lacks the necessary humidity and water for breeding. The northern limit of Plasmodium falciparum malaria in Africa is the Sahel, where rainfall is an important limiting factor in disease transmission. Malaria has decreased in association with long-term decreases in annual rainfall in Senegal and Niger.

We certainly do not hope that drought provides a ‘solution’ for malaria elimination in endemic countries.  What these climate proceedings should remind us of is the need for strong surveillance systems that can detect and respond to trends.

Countries therefore, need to be ready to adapt their malaria control efforts not only to the positive results of universal coverage but also to the negative spread and shifts in malaria transmission that could come from climate change.

When the international effort to eradicate guinea worm started in 1987 the focus was on only 20 currently endemic countries.  Tayeh and Cairncross report the status of these countries at the end of 2008 –

• 6 have interrupted transmission and been certified as free of guinea worm
• 8 have interrupted transmission and certification is under way
• 6 are still reporting cases, of which three are a major focus

Guinea worm is a highly focal disease that does not move too easily. The differences in transmission and the sheer number of endemic countries sets malaria off clearly from guinea worm. But are there lessons to learn?

Of concern here is the process of certification that transmission has stopped.  Looking at malaria’s pathway to elimination, we realize that most countries are in the scale-up phase of control and have a long way to go to sustain control and enter pre-elimination, let alone elimination and then prevention of re-introduction.  At some point in the elimination phase, which could be 20 years from now, countries will need to be certified free of malaria.

Tayeh and Cairncross address the realities that larger scale eradication programs like polio take a regional approach to certification, as a country-by-country approach would be too costly.  They also discuss the dangers of re-introducing a disease to places that are free of transmission, which corresponds well with the final phase of the malaria elimination pathway.

Another issue is the challenge of identifying cases when transmission becomes very low. The system of rewards to citizens may not be most appropriate for malaria, but the ability to keep people engaged in eradication efforts when they don’t see a reason will be difficult.

What our colleagues don’t mention is the challenge of false positives. We found that local beliefs in guinea worm endemic areas can lead to high false positive rates on surveys – that swelling on his leg, that ache in her stomach, those rashes on his body.  Local beliefs about malaria presentation abound, too.  It is good, therefore, to start considering what surveillance and certification of malaria elimination will look like now, so a good system is in place when the time comes. In fact we may get good opportunities to practice in places like Zanzibar.

Malaria researchers in Niger have been observing malaria transmission and mosquito populations in two villages over two years and discovered major differences even though the settlements are only 30 km apart. Finding a 10-fold difference in mosquito density, the authors conclude that, “The highly focal nature of malaria in the Sahel makes detailed representation necessary to evaluate village-level risks associated with hydrology-related vector population variability.”

Other factors affecting transmission differentials include seasonal availability of nutrients and predators. Ultimately the authors recommend, “Topography, vegetation, soil type differences as well as shallow groundwater behaviour must all be incorporated at appropriate scales in order to accurately evaluate malaria transmission at the village scale using coarse resolution climate models.” These issues should inform ‘malaria early warning systems’ at a more focused level, the village.

The researchers were concerned about, “The sudden appearance of widespread but temporary water pools gives rise to a rapid increase in mosquito populations clustered around human habitation, resulting in the highly focal malaria transmission that is a characteristic of Sahel villages.”  While these local variations are known, the problem arises when computer models lump together areas of tens to hundreds of kilometers in size together, missing the local differences that imply different control strategies.While the overall climate and vector behavior were not different, local hydrology was. The researchers specifically modeled differences in “local topography, distributed land cover type, and subsurface hydrology environment.”

Such differences in transmission dynamics have also been reported for urban malaria. For example, in Luanda, Angola transmission was more than four times greater in areas 15 km or more beyond the city core, compared with the central areas.  In Dakar, Senegal transmission was highly focal, and “no mean figures for transmission would provide a comprehensive picture of the situation; risk evaluations should be conducted on a local scale,” even for areas only a few kilometers apart. Urban agriculture provides another example of very focal transmission.

A the present moment when countries are focusing on large efforts to ‘scale up for impact’ the small scale or focal differences might be ignored. As we move along the pathway toward elimination, more focal surveillance and intervention will be essential for mopping up transmission and monitoring against reinfestation. Now is the time to build those surveillance systems so that countries and communities will not be caught unaware when malaria attempts to make a comeback some years hence.

Non-endemic does not mean no malaria.  The Caribbean Epidemiology Centre (CAREC) explained that, Jamaica has been malaria-free for over fifty (50) years, although a number of imported malaria (Plasmodium falciparum) cases were identified each year.” That said, Rawlins and colleagues observed that there were 897 reported malaria cases in the Caribbean Epidemiology Centre (CAREC) Member Countries (CMCs) between 1980 and 2005 with Jamaica accounting for 38.4%.

Then the situation changed briefly. WHO posted information in 2007 that, “The Ministry of Health of Jamaica has confirmed 280 cases of malaria due to Plasmodium falciparum on the island between 6 November 2006 and 3 February 2007. Of these reported cases, 264 have occurred in Kingston, 12 in St Catherine, 3 in St Thomas and 1 in Clarendon. There have been no reported deaths due to malaria.”

WHO recommended that while “Jamaica is a non-endemic country for malaria … The occurrence of this outbreak highlights the importance of conducting surveillance in countries that are non-endemic to malaria.”

[LEFT: malaria free but not alligator free]

Likewise Rawllins et al. warned that, “All the essential malaria transmission conditions–vector, imported malaria organism and susceptible human host–now exist in most CMCs. A call is now made for enhanced surveillance, vector control and anti-malaria skills to be established in CMCs.”

We cannot turn our backs on malaria – malaria carrying mosquitoes do not mind whether they bite us in front or in back.