Tropical Health Matters

In Mali, ‘shocking levels’ of malaria misdiagnosis are being reported. “The discrepancy between real and assumed cases has reached “shocking” levels all over Africa … Malaria diagnostics in Mali rely on expensive equipment which most health clinics, particularly in rural areas, cannot afford and do not have the trained staff to use … As a result most doctors “make assumptions based on suspicion,” he said, leading to over-treatment of malaria cases … most people who develop a fever in Mali do not visit a health clinic at all either because they live too far away, or are unwilling to pay up to US$0.95 for a consultation.”

They self diagnose and treat instead.” IRIN reports that, “Up to 70 percent of cases of feverish illness in children are diagnosed and treated at home.” In contrast, “Laboratories the gold standard. Mali needs more and better-equipped laboratories to combat mass misdiagnosis.”

Although the news release about Mali does not give numbers, they may be quite substantial. Two years ago a medical officer working for a major corporation in Nigeria discussed the experiences from their company’s employee/family clinics and showed that without laboratory tests at least 75% of patients whom clinicians diagnosed as having malaria were free of parasites. The company thought that lab tests resulted in a major savings for the company in terms of malaria pharmaceuticals.

Many diseases present with malaria-like symptoms, including dengue fever, which is poorly recognized in Africa. Nordstrand et al. (2007) report that in the absence of laboratory diagnosis, tickborne relapsing fever is treated as malaria in Togo.

There are concerns about the cost of laboratory diagnosis. Rapid Diagnostic Tests (RDTs), though not without expense, are a solution in low resource settings. Hopkins et al. (2008) report that “Based on the high PPV (positive predictive value: 93%) and NPV (negative predictive value: >97%), HRP2(histidine-rich protein 2)-based RDTs are likely to be the best diagnostic choice for areas with medium-to-high malaria transmission rates in Africa.”

Even when laboratory diagnosis is available, it may not be used. As Polage and colleagues observed in Ghana, “Perhaps the most significant barrier to laboratory use was physicians’ reliance on clinical judgment.”

A lesson here is that clinical diagnosis may be no better that self-diagnosis. An interesting question is by how much would the world’s burden of malaria be reduced simply by performing an accurate diagnosis in a laboratory or with RDTs?

Workers Day is a time to remember that malaria affects the whole population in endemic countries. The American Association for the Advancement of Science reminds us that, “Malaria is likely … to have a long-term impact on household and community productivity.” The long term effects come in part because malaria interferes with the schooling of children.

Bleakley points out that the connection between malaria and poverty may be a two-way street – malaria depresses productivity. But poverty itself depresses the family’s and the community’s ability to fight malaria. The effects may arise from continued exposure to childhood malaria. While an individual episode as an adult may not have large effects, cumulative exposure may. Bleakley explained that after eradication programs in the Americas, “In both absolute terms and relative to the comparison group of non-malarious areas, cohorts born after eradication had higher income and literacy as adults than the preceding generation.”

In many endemic countries a large portion of the labor force works in the informal sector where issues like absenteeism and lost productivity are least likely to be measured. In these settings, “The burden of malaria is often greatest among the very poor as they are least able to protect themselves and seek treatment. Hence, malaria can exacerbate existing inequalities.”

As Onwujekwe et al. (2004) note, “Malaria is the leading cause of mortality and morbidity in Nigeria, resulting in the decreased productive capacities of households and increased poverty.” This creates inequalities in a household’s ability to acuire and benefit from malaria control interventions.

Likewise, Chuma and colleagues (2006) note that wealthier households are better able to cope with malaria. “The impacts of malaria on household economic status unfold slowly over time. Coping strategies adopted can have negative implications, influencing household ability to withstand malaria and other contingencies in future. To protect the poor and vulnerable, malaria control policies need to be integrated into development and poverty reduction programmes.”

These facts are why advocates for malaria control state that all people in endemic communities, regardless of age or occupation, should have the benefits of free malaria treatment and ITNs/LLINs.