Overdiagnosis of malaria in patients with severe febrile illness in Tanzania: a prospective study

Objective To study the diagnosis and outcomes in people admitted to hospital with a diagnosis of severe malaria in areas with differing intensities of malaria transmission.Design Prospective observational study of children and adults over the course a year.Setting 10 hospitals in north east Tanzania.Participants 17 313 patients were admitted to hospital; of these 4474 (2851 children aged under 5 years) fulfilled criteria for severe disease.Main outcome measure Details of the treatment given and outcome. Altitudes of residence (a proxy for transmission intensity) measured with a global positioning system.Results Blood film microscopy showed that 2062 (46.1%) of people treated for malaria had Plasmodium falciparum (slide positive). The proportion of slide positive cases fell with increasing age and increasing altitude of residence. Among 1086 patients aged ≥ 5 years who lived above 600 metres, only 338 (31.1%) were slide positive, while in children < 5 years living in areas of intense transmission (< 600 metres) most (958/1392, 68.8%) were slide positive. Among 2375 people who were slide negative, 1571 (66.1%) were not treated with antibiotics and of those, 120 (7.6%) died. The case fatality in slide negative patients was higher (292/2412, 12.1%) than for slide positive patients (142/2062, 6.9%) (P < 0.001). Respiratory distress and altered consciousness were the strongest predictors of mortality in slide positive and slide negative patients and in adults as well as children.Conclusions In Tanzania, malaria is commonly overdiagnosed in people presenting with severe febrile illness, especially in those living in areas with low to moderate transmission and in adults. This is associated with a failure to treat alternative causes of severe infection. Diagnosis needs to be improved and syndromic treatment considered. Routine hospital data may overestimate mortality from malaria by over twofold.     

To what extent can traditional medicine contribute a complementary or alternative solution to malaria control programmes?

Background

Sulphadoxine and pyrimethamine are anti-folate drugs that show synergistic anti-malarial effect. Point mutations in dihydrofolate reductase (dhfr) and dihydropteorate synthatase (dhps) cause anti-folate drug resistance phenotype in human malaria parasites. This study presents pattern of point mutations in dhfr/dhps genes among Indian sub-continent.

Methods

Microscopically diagnosed one hundred Plasmodium vivax field isolates were collected from five widely separated geographical regions of India. Dhfr and dhps genes were PCR amplified and sequenced. Previously published mutations data were collected and analyzed using Chi square test to identify geographical cluster of mutant/wild type genotypes.

Results

Sequence analysis revealed single (S58R), double (S58R/S117N) and quadruple (F57L/S58R/T61M/S117T/) point mutations at dhfr and single (A383G) to double (A383G/A553G) mutations at dhps in P. vivax field isolates. In addition, three new mutations were also observed at dhfr. Both, dhfr and dhps genes revealed tandem repeat variations in field isolates. Dhps revealed very low mutation frequency (14.0%) compared to dhfr (50.70%). Comparative analysis revealed a progressive increase in frequency of quadruple mutant dhfr genotype (p < 0.001) within five years in north-eastern state (Kamrup, Assam). Frequency of dhfr genotypes revealed three distinct geographical clusters of wild (northern India), double mutant (southern India), and quadruple mutant (north-eastern and island regions of India) on the Indian sub-continent.

Conclusion

Study suggests that SP may be susceptible to P. vivax in India, except Andaman and north-eastern state. The distinction of geographical regions with sensitive and resistant parasite phenotypes would be highly useful for designing and administering national anti-malarial drug policy.     

To what extent can traditional medicine contribute a complementary or alternative solution to malaria control programmes?

Recent studies on traditional medicine (TM) have begun to change perspectives on TM effects and its role in the health of various populations. The safety and effectiveness of some TMs have been studied, paving the way to better collaboration between modern and traditional systems. Traditional medicines still remain a largely untapped health resource: they are not only sources of new leads for drug discoveries, but can also provide lessons and novel approaches that may have direct public-health and economic impact. To optimize such impact, several interventions have been suggested, including recognition of TM's economic and medical worth at academic and health policy levels; establishing working relationships with those prescribing TM; providing evidence for safety and effectiveness of local TM through appropriate studies with malaria patients; spreading results for clinical recommendations and health policy development; implementing and evaluating results of new health policies that officially integrate TM.