Posts or Comments 18 July 2024

Monthly Archive for "March 2011"

Mortality Bill Brieger | 30 Mar 2011

Youth vs Children – a mortality trade off

BBC has reported on a new study that shows global mortality trends favoring young children compared to adolescents and youth. “Young men aged 15-24 are now two to three times more likely to die prematurely than young boys aged one to four.” Female youth are no better off that their younger counterparts.

The study, published online in The Lancet, reviewed data from an economic spectrum of 50 countries over 50 years.  The need for available high quality data meant that no Subsaharan African country, where the burden of malaria is highest, was included.

Increased rates of injury and greater urbanization were key factors in mortality among youth. The former is not conducive to malaria, but the latter combined with the tendency toward more risky behaviors, does not exclude other infectious diseases, especially HIV.

under-5-mortality-rate-trends.jpgEven though they could not include African countries, the researchers did study at least 15 low or very low income countries and therefor, encourage continued monitoring in other low income settings. They note that trends such as urbanization and greater prevalence of non-communicable disease and injury are occuring in low income countries, too and “Because some of the greatest improvements in mortality in children younger than 5 years have been made in very low-income countries.”  Unicef’s 2011 State of th World’s Children supports the latter assumption as seen in the attached graph.

Although the authors note a decreasing trend in maternal mortality globally, pregnant teenage women in malaria endemic areas are still at high risk. These are often the group that do not get adequate antenatal care including prevention of malaria in pregnancy.

dscn0540a.jpgAn accompanying editorial in The Lancet calls attention to the general neglect of the health of adolescents and youth and reminds us that this new research shows “that mortality in young people aged 10–24 years has proved less responsive to the international alliances and interventions that have so effectively reduced early childhood mortality worldwide, emphasising the need for a vigorous global focus on the health and mortality of adolescents and young adults.”

Our efforts at malaria elimination and child survival will come to naught, if those children who make it past their fifth birthday never realize their potentials as adult members of the society.

Eradication &ITNs &Universal Coverage Bill Brieger | 26 Mar 2011

Net coverage; how much is enough?

We are unlikely to eliminate mosquitoes, according to Tanya Russell and colleagues, but she notes that this should not stop us from implementing all available interventions. Specifically their study of malaria vectors in Tanzania found that the at reduced densities of mosquito populations, they try to reproduce more, meaning we may never get below 10% mosquito elimination.

Instead, a member of the National Malaria Control Program in Tanzania says our goal “should be to reduce, and eventually halt, transmission of the parasite, rather than eliminating the vector.” If we can achieve no more than 90% elimination of mosquitoes, what is a realistic coverage figure for malaria interventions?

Applications of net and case management strategies in Rwanda and Ethiopia have definitely shown that major drops in malaria incidence are possible.  But the RBM targets of 80% coverage (85% for the US President’s Malaria Initiative) are elusive.  Demographic and malaria surveys from Senegal, Liberia and Nigeria show that even in homes that own nets, net use among people at most risk, does not reach this target.

Are we really sure that 80% is the right target?

Fred Binka was one of the first to demonstrate that people living in homes without nets can be protected by their neighbors’ nets, which kill mosquitoes in the community. ITNs “provided very good personal protection to children using them, and also protected nonusers in nearby compounds. Among nonusers, the mortality risk increased by 6.7% with each additional shift of 100 m away from the nearest compound” with nets. This led the researchers to speculate on the need to study whether the “mass effect from a small number of highly dispersed nets would provide equivalent protection to complete coverage.”

A few years later William Hawley and co-researchers reported that, “protective effect of ITNs on compounds lacking ITNs located within 300 meters of compounds with ITNs for child mortality, moderate anemia, high-density parasitemia, and hemoglobin levels.”

As part of the move toward universal coverage, Killeen and colleagues examined the importance of considering all household members, not just the ‘vulnerable.’ The group condluded that …

Using field-parameterized malaria transmission models, we show that high (80% use) but exclusively targeted coverage of young children and pregnant women (20% of the population) will deliver limited protection and equity for these vulnerable groups. In contrast, relatively modest coverage (35%–65% use, with this threshold depending on ecological scenario and net quality) of all adults and children, rather than just vulnerable groups, can achieve equitable community-wide benefits equivalent to or greater than personal protection.

Barat has called for ‘data driven decision making‘ in the effort to eliminate malaria. Using data in models as done by Killeen is a further important step. The onchocerciasis control community has been working with such models for over 15 years now. New data are fed into the Onchosim model based on program progress such that it is possible to forecast that onchocerciasis could be eliminated from areas with high initial prevalence if 65% coverage of ivermectin treatment were maintained for at least 25 years.

Unlike onchocerciasis control, malaria elimination rests on multiple interventions.  This makes modeling much more urgent, as outlined by malERA’s research agenda for eradication. Since universal coverage unfortunately does not mean universal usage, we need to seek valid data and models to help us plan for distribution of malaria interventions more strategically in ways that are affordable and can be maintained and at the same time can achieve maximum reductions in morbidity and mortality.

Equity &ITNs Bill Brieger | 24 Mar 2011

Net Equity – SUFI or SUFE?

nigeria2.jpgMalaria elimination efforts move along a pathway outlined by the Roll Back Malaria Partnership that begins with limited control, moves on to scaling up and then aims as sustaining the scaled up interventions so that incidence drops and we can enter the pre-elimination phase.  The scale up efforts that have been most intense in the past three-year effort to reach universal coverage (UC) have been known by the acronyn SUFI – scale up for intervention.

SUFI and UC are also viewed against the backdrop of RBM targets set in 2000 to achieve 60% coverage by 2005 and 80% by 2010.  The implication is that we may claim success with 20% of the population still not reached, which appears to counter the aims of UC.  Therefore a bigger question is whether we are simultaneously achieving SUFE – scale up for equity.

liberia2.jpgFrom the standpoint of malaria control equity should focus on whether those people who are most vulnerable to infection have access to interventions.  Vulnerability or risk has been viewed from two perspectives: 1) people who are more likely to experience infection because of their immune status such as children below 5 years of age and pregnant women and 2) people living in poverty whose financial and housing situation expose them more to infection and whose incomes are more at risk when they suffer from malaria.

Presented here are snapshots from health surveys in Nigeria, Liberia and Senegal that compare household net ownership with wealth quintile (Demographic and Health Survey, Malaria Indicator Survey). These countries have achieved differing levels of coverage and access to low income groups that help us question how equity relates to malaria control.

Nigeria is characterized by low overall coverage. During recent discussions at a retreate among maternal and child health professionals, colleagues raised the question of whether we can consider equity when coverage is very low. Nigeria prior to the mass net distribution efforts of 2009-11 provides some interesting information for the discussion. Although households in the lower wealth quintiles are slightly more likely to have any kind of bednet, the ownership of an insecticide treated net (ITN) is much greater in the wealthier homes. This may not be unrelated to the fact that ITNs in the early phases of control were often sold or subsidized, limiting their access to people with better income.

senegal2.jpgLiberia and Senegal with moderate and higher levels of coverage display the same overall trend as Nigeria with poorer household more likely to have some kind of bednet, but when it comes to ITNs, the poorer ones also have some advantage.  At the time of their surveys, both Senegal and Liberia had been doing some mass net distributions, and the benefit to the lower income people in their countries seems apparent.  It should be noted that higher income people may not need nets as a main protecteive measure if they live in better constructed homes that usually have window and door screening, an expensive intervention on its own.

One might conclude that Universal Coverage does have a strong equity or SUFE component.  We also need to investigate whether other interventions like prompt case management and intermittent preventive treatment are also reaching the people in most need.

Community &Performance Bill Brieger | 22 Mar 2011

Supervising volunteer community health workers

supervision-chw.jpgVolunteer community or village health workers (CHWs) are crucial human resources to increase and sustain coverage of malaria interventions. Small and large scale training programs have abounded over the years stimulated by the philosophy of the Alma Ata Declaration on Primary Health Care. Unfortunately, CHW programs often fade after a few years because a donor supported project closed or funds dried up for a public health program and the health staff who trained the CHWs loose touch with them.

Without supervision and encouragement CHWs loose interest and forget what they learned. The challenge therefore is to design an appropriate supervisory system for limited resource settings.

Experience with village health workers for primary care and community community directed distributors for onchocerciasis control have demonstrated that effective and appropriate supervision of CHWs requires three main components or partners as seen in the attached diagram.

Staff of the health facility nearest to the community should have initially reached out to the community to assess their interest in community health interventions and helped them organize. Included in this organization is selection of trusted community volunteers to serve as CHWs.  These health staff provide technical supervision on the health services being provided (case management, net distribution) and management processes (good service records and reports).

Health staff may not be able to visit each village in their service catchment areas frequently, but they can host monthly or quarterly meetings where CHWs bring their service records, collect new supplies and receive technical updates. Health staff review the records for accuracy and give pointers to improve data and service quality.

The second partner in CHW supervision are the community members who actually selected the volunteers. The CHWs must be held accountable to the people who selected them. CHWs can be asked to report at community meetings about progress and services provided, and community members can give feedback on the quality of these services.

The third partner is the CHWs themselves.  Often CHWs in a locality form an association and meet regularly.  These meetings create a form of peer supervision.  CHWs share their experiences and lessons learned. They advise each other and jointly solve common problems such as community refusal to talke certain medicines or hand up their bednets. CHWs can even take turn reviewing the basic lessons they learned at the start.

Supervision does require that people get together and have a dialogue about their work. This often means some degree of travel. Here is where we need to rely on local knowledge and make supervision convenient for all. for example, health staff can schedule such gatherings on market days when CHWs and other villagers would normally come to town.

Until we move to the local level and find locally appropriate solutions to supervision, we will not be able to achieve universal coverage.

Community &Partnership Bill Brieger | 11 Mar 2011

Peace Corps Senegal

Thanks for the recognition of the efforts of Peace Corps Volunteers worldwide in malaria prevention. PC Volunteers and our partners here in Senegal pioneered the universal bed net coverage and malaria prevention education approach that has now been adopted by PMI and the Senegalese national malaria control program.

Already 7 of the nation’s 14 regions have achieved true universal coverage, including a pre-distribution house by house sleeping area/bed net census, village distribution and education events, and post-distribution hang checks. There is much left to do, but Senegal has made tremendous progress, and Peace Corps Volunteers have been at the center of the fight.

Looking forward as the agency celebrates 50 years, Peace Corps across Africa is developing a comprehensive campaign to replicate and adapt the experiences of PC/Senegal to the other two dozen PC programs on the continent.

Thanks again for recognizing the important role that our Volunteers can and will play in the effort to reduce malaria in Africa.

Chris Hedrick
Country Director, Peace Corps/Senegal

Mosquitoes &Plasmodium/Parasite Bill Brieger | 10 Mar 2011

Mosquitoes also do not want to be infected

When the small copepod or cyclops swallows a guinea worm larva, seeing it as food, several things may happen as the larva develops – either someone swallows the cyclops when drinking the pond water, continuing the guinea worm cycle, or the larva grows so large that the cyclops is destroyed. Control measures have included putting temephos in ponds to kill the cyclops. All of these mean death for the cyclops. None of these alternatives bode well for the cyclops.

dscn0333-sm.jpgIt is not surprising to learn, as reported in PLoS Biology that disease vectors or intermediate hosts themselves are not very ‘happy’ to get infected with disease organizms that are later passed to humans. In essence Anophleles gambiae mosquitoes have genes that encode ‘essential components of the mosquito immune defense against malaria parasites.’

Furthermore, these genes are not static. Rottschaefer and colleagues report that, “Our data indicate that functionally variable APL1 alleles are evolutionarily maintained to combat diverse pathogens, perhaps including but probably not restricted to Plasmodium species.”

Most malaria control measures to date that involve the vector are aimed at killing, repelling or sterilizing.  These range from the newest, a toxic sugar bait, to the widely used instecticide treated bednets. There is exploration into a human vaccine that would prevent the parasite from developing in the mosquito.

While mosquitoes are certainly a nuissance in their own right, they are not necessarily the main enemy in the fight against malaria. We should certainly continue using bednets and indoor spraying and in appropriate cases larviciding, as major gains have been made from these. It would be hard though to completely eliminate the vectors.  Therefore continued research is needed on vaccines and genetic modifications that make mosquitoes a hostile host to plasmodium species.

Health Systems &Peace/Conflict Bill Brieger | 04 Mar 2011

Fragile States, Fragile Malaria Control

When the Roll Bank Malaria Partnership was launched 13 years ago, one of the basic tenents of the effort was that malaria control could not succeed without a concurrent reform and strengthening of health systems.  It was health systems weaknesses (in addition to pesticide resistance) that led to the failure of the first campaign to eradicate malaria.  But, strong health systems cannot exist in weak states.

photo-anthony-morland-irin-car-infrastructure-destroyed.jpgIn one example, IRIN reported this week that, “After decades of political violence, displacement and insecurity caused by clashes between rebel groups and government forces, as well as armed bandits, thousands of people in Central African Republic (CAR) are vulnerable to disease and have little access to health services, aid agencies say.”

In particular, IRIN noted that, “Malaria remains the leading cause of morbidity, accounting for 13.8 percent of deaths,” in CAR. Immunization coverage has also dropped since 2006 due to population displacements. “Uder-five mortality is 176 deaths per 1,000 live births and infant mortality 106 deaths per 1,000 live births. The country also has the highest maternal mortality rate in Africa, with 1,355 deaths per 100,000 live births.”

Last month IRIN asked whether Côte d’Ivoire was ‘heading for bust’ as a result of the political instability following the controversial presidential elections.  There is general disorder, and “banks are closing because banks don’t like Kalashnikovs; money doesn’t like disorder.”  People don;t have access to cash and have to make hard choices between paying bills and getting treatment for illnesses like malaria that don’t stop just because the country is in conflict.

Not only banks, but donor agencies do not like disorder. IRIN also disclosed that, “Support from another key donor, the Global Fund to Fight AIDS, Tuberculosis and Malaria, which has approved grants worth more than US$290 million to Côte d’Ivoire, has also been affected by the crisis. Contacted by IRIN in Geneva, the Fund confirmed that: “Due to the political instability the Global Fund has taken measures to safeguard its stocks and funds in Ivory Coast, but continues allowing procurement and distribution of life saving drugs against HIV virus and malaria.” The Global Fund is also authorizing implementers to carry on essential operational activities on a case-by-case basis.”

When fragile states cannot control their malaria stituation, their neighbors are at risk. For example, USAID observed that, “Due to prevailing instability in Darfur and CAR, the voluntary repatriation of the estimated 323,280 refugees currently residing in eastern and southern Chad is unlikely in 2011, according to the U.N.” The CAR refugees are located in a highly malaria endemic area of Chad and pose an additional burden to Chad’s already stretched health care system.

The United Nations and the African Union should see the link between conflict/insecurity and malaria/death. When a country is in disorder, mortality often comes more from disease than bullets.