Tropical Health Matters

An editorial marking World Malaria Day in Nigeria’s Daily Trust exhorted readers as follows: “If only we can learn to clean our gutters, fumigate our drainage channels, evacuate our rubbish heaps and take other simple and sensible steps to eradicate or reduce the vector that causes malaria, we will not have cause to embark on the yearly ritual of lamenting about how we suffer so much from this public health challenge.”

While mosquitoes may breed in discarded cans and tires in rubbish heaps or in gutters in out cities, the likely culprits are Aedes species, which carry yellow and dengue fevers, and Culex species, which carry filariasis and a variety of viral diseases. Eliminating such breeding sites will certainly go a long way to promoting public health, but may not elimnate the breeding of the Anopheles species of mosquitoes that carry malaria.

For Anopheles mosquitoes the US Centers for Disease Control and Prevention states that, “The larvae occur in a wide range of habitats but most species prefer clean, unpolluted water. Larvae of Anopheles mosquitoes have been found in fresh- or salt-water marshes, mangrove swamps, rice fields, grassy ditches, the edges of streams and rivers, and small, temporary rain pools.”  In contrast a study from Cameroon identified the following breeding sites for Aedes, many of which could be found in a refuse heap.:

Used tire, Plastic container, Can and broken bottle, Plastic cup, 200-L barrel, Abandoned car part, Cement washtub, Flowerpot, Tree hole, Cow horn, Cocoa pod, Enameled plate and Snail shell

The Press is an important Advocate in the fight to eliminate malaria, but it’s role is only as good as it’s access to scientifically sound information, which these days can be obtained on internet sites like those of WHO, RBM and CDC, but just as easily – a phone call to a local expert in the Ministry of Health or a local University.

Greetings on World Water Day, which interestingly is taking place just about one month before World Malaria Day. The theme for the upcoming World Malaria Day focuses on malaria’s lack of respect for borders, and the challenge of guaranteeing and preserving safe water supplies also cuts across national boundaries.

The connection between water and the breeding of malaria carrying mosquitoes is well known. In a most simple example, one can visualize many of the newly installed borehole wells around Africa that were installed without adequate community involvement. in very little time, these become poorly maintained and spill off water collects into puddles ideal for anopheles mosquitoes.

One can also recall numerous agricultural projects that create mosquito breeding grounds through irrigation canals or simply land clearing that allows rain water to collects. When floods come, which has been very common in southeast Africa recently, communities lose access to safe water while ironically being surrounded by expanses of rivers that overflowed their banks, creating breeding opportunities for mosquitoes.

The ultimate lesson is that both programs, safe water and malaria control, cannot be solved in a vertical way. There needs to be collaboration and a broader development approach that addresses underlying

NAM News Network reported that, “On March 27, a dedicated team of individuals will embark on a two-month humanitarian journey that will start in the North Western Zambia through six countries along the (2,500 km) Zambezi River to the Mozambique Delta where the river meets the Indian Ocean, in an effort to raise malaria awareness and to help eradicate the spread of the disease in the SADC region.” The expedition plans to reach “remote populations with access to protective bed nets and malaria treatment drugs.”

The Zambezi has also drawn attention of malaria commodity donors in the recent past. Although the Zambezi has “one of the Seven Wonders of the World, Victoria Falls,” It also has zones “where cases of malaria are reported throughout the year” according to the Zimbabwe Red Cross, who organized distribution of over 3,000 nets in 2005 and 2006. USAID also recently supported a year-long expedition down the Zambezi to bring services and attention to the remote populations affected by malaria.

The 2008 expedition is described by the Roll Back Malaria Partnership: “The 2-month expedition along the Zambezi River will raise awareness among both local communities and international donors of what is needed to fight malaria and help strengthen cross-border collaboration on malaria-related policies. The Zambezi Expedition project, supported by 6 countries from the Southern African Development Community, has received financial backing from the nonprofit and the private sectors and will be steered by the Roll Back Malaria Partnership.” AFP explained that, “The teams would distribute mosquito nets and medicines in the communities they visit, and doctors would conduct diagnostic tests for the parasitical disease that claims the life of an African child every 30 seconds.”

Campaigns and expeditions certainly help, but what is needed most is continued regional planning and cooperation since malaria and mosquitoes do not respect boundaries. It is hoped that the Trans-Zambezi countries can put together a joint proposal to the Global Fund for the upcoming Round 8 funding. All partners should join together to support this important regional activity. This will also require much good will and collaboration among the Central Coordinating Mechanisms of the countries to support a joint proposal.

Based on the possibility that “Anecdotal evidence suggests that smoke may play an important role by providing protection from biting insects and that efforts to reduce smoke may increase exposure, particularly to mosquitoes and malaria,” Biran et al., recently conducted a review of previous research. Various domestic sources of smoke were found including that from cooking fires and local herbs that were burnt to repel mosquitoes. Although they did not find much research that addressed the question directly, they were able to suggest the following:

• Smoke from domestic fuel use probably does not have much effect on mosquito feeding
• Mosquito feeding is affected by smoke from certain plant products traditionally used as repellents
• Soot from domestic fires, although not toxic to mosquitoes, does not impair the effectiveness of ITNs
• Soot may, however, increase the frequency with which nets are washed and thus accelerate the loss of insecticide from ITNs

The authors concluded that, “There appears to be a good health argument for continuing efforts to reduce indoor air pollution, even in areas where malaria is endemic. It is likely that such efforts will have substantial health benefits in reducing respiratory disease and unlikely that the reduction of smoke per se will have any significant health costs in terms of increased malaria.”

Smoke as a mosquito control intervention is not common – in fact it was as far back as 1923 that the Transactions of the Royal Society of Tropical Medicine and Hygiene contained an article explaining how smoke from burning straw was used to drive mosquitoes from hiding places where they could be manually killed.

While the identification of local repellent herbs was important, another common source of smoke that was not addressed in the recent article was the mosquito coil. These are cheap and ubiquitous in endemic communities, although some community members do complain about the fumes causing breathing problems. According to Pauluhn and Mohr, “Overnight exposure to the smoke from burning mosquito coils (manufactured in Indonesia) is unlikely to be associated with any unreasonable health risk.” Of course people in endemic communities use coils over many nights (see comment).

The question is whether coils work. Lawrance and Croft reviewed literature and concluded that, “There is no evidence that burning insecticide-containing mosquito coils prevents malaria acquisition. A randomized field trial should be conducted, with malaria incidence as a primary outcome. There is consistent evidence that burning coils inhibits nuisance biting by various mosquito species. The potential harmful effects of coil smoke on human users should be investigated.”

In the end we don’t need smoke and mirrors to control malaria, but reliable and adequate supplies of interventions of known value such as long-lasting insecticide treated nets.

In a Washington Post book review, “Buyer Beware: Are we training our kids to be consumers rather than citizens?” Barry Schwart ( Sunday, April 8, 2007; Page BW08) noted that, “Viagra and Botox become readily available here while drugs to combat life-threatening malaria and diarrhea are not in developing countries.”

An opinion piece in The Nation entitled “Pigs in Space” (7 April 2007) observed that a millionaire Hungarian-American software programmer paid $20 million to be escorted to the Kazakh steppes, packed into a Russian Soyuz rocket and blasted towards the international space station. The Nation suggested that, “Simonyi might have spent his money fighting AIDS, or building housing for Hurricane Katrina survivors, or providing clean water to developing nations, or mosquito netting and medicine for malaria patients, or musical instruments for needy, photogenic, musically-gifted inner city school children or…well, depressingly, the list goes on and on.”

The Associated Press reported from the recently concluded climate change conference in Brussels that, “Two distinctly different groups, data-driven scientists and nuanced offend-no-one diplomats, collided and then converged this past week. At stake: a report on the future of the planet and the changes it faces with global warming.” The meeting reported that, “Malaria, diarrhea diseases, dengue fever, tick-borne diseases, heat-related deaths will all rise with global warming.”

In an upcoming issue of Newsweek International Jason Overdorf reports that along with global warming there is an increased movement of malaria bearing mosquitoes into highland regional of Asia, Latin America and Asia. He quotes another study that states, “temperature increases from 0.5 degrees to 3 degrees can double the population of Anopheles mosquitoes, which carry malaria.” Economic conditions that enable people in northern countries to afford window screens and air conditioning may stave off the spread of disease.