G6PD Deficiency at Sumba in Eastern Indonesia Is Prevalent, Diverse and Severe: Implications for Primaquine Therapy against Relapsing Vivax Malaria

Safe treatment of Plasmodium vivax requires diagnosis of both the infection and status of erythrocytic glucose-6-phosphate dehydrogenase (G6PD) activity because hypnozoitocidal therapy against relapse requires primaquine, which causes a mild to severe acute hemolytic anemia in G6PD deficient patients. Many national malaria control programs recommend primaquine therapy without G6PD screening but with monitoring due to a broad lack of G6PD deficiency screening capacity. The degree of risk in doing so hinges upon the level of residual G6PD activity among the variants present in any given area. We conducted studies on Sumba Island in eastern Indonesia in order to assess the potential threat posed by primaquine therapy without G6PD screening. We sampled 2,033 residents of three separate districts in western Sumba for quantitative G6PD activity and 104 (5.1%) were phenotypically deficient (\u3c4.6U/gHb; median normal 10U/gHb). The villages were in two distinct ecosystems, coastal and inland. A positive correlation occurred between the prevalence of malaria and G6PD deficiency: 5.9% coastal versus inland 0.2% for malaria (P\u3c0.001), and 6.7% and 3.1% for G6PD deficiency (P\u3c0.001) at coastal and inland sites, respectively. The dominant genotypes of G6PD deficiency were Vanua Lava, Viangchan, and Chatham, accounting for 98.5%of the 70 samples genotyped. Subjects expressing the dominant genotypes all had less than 10% of normal enzyme activities and were thus considered severe variants. Blind administration of anti-relapse primaquine therapy at Sumba would likely impose risk of serious harm

Demographic, malaria and G6PDd prevalence data by gender and ecosystem in western Sumba.

<p>n = sample number.</p><p>¹ Population number was obtained from central agency statistic from each district.</p><p>² Microscopy diagnosed.</p><p>³ One subject experienced mixed infection of <i>P</i>. <i>falciparum</i> and <i>P</i>. <i>vivax</i>.</p><p>⁴ Hb < 10 g/dl.</p><p>⁵ G6PD activities ≤4.6 U/gHb.</p><p>⁶ Samples screened as G6PD deficient but declined, absent or failed to be DNA extracted.</p><p>Demographic, malaria and G6PDd prevalence data by gender and ecosystem in western Sumba.</p

Impact of Hb level on G6PD activities.

<p>Blue line represents those samples having extremely high G6PD activity and some degree of anemia (R² = 0.08) and red line represents those having normal Hb level (R² = 0.48) and t-value = 28.6 (p<0.001).</p

A) Schematic work flow of the study in western Sumba in 2012 and B) map of G6PD deficiency and malaria prevalences in study sites in Sumba.

<p>Small inlet showed the map of Indonesia and where Sumba island is located.</p

Scatter plot of G6PD activities of G6PD deficient and normal subjects from Trinity quantitative versus kinetics assays measured in U/g Hb.

<p>The different colours represented different variant (V in either normal, heterozygous and hemizygous mutants. VL Het, VC Het and CT Het represented heterozygous females having Vanua Lava, Viangchan and Chatham variant respectively. VL Hem, VC Hem and CT Hem represented hemizyogous males having Vanua Lava, Viangchan and Chatham variant respectively.</p

Enzymatic parameters from purified G6PD from study subjects in western Sumba according to genotype.

<p>* median of the samples analyzed;</p><p>**cannot be calculated because the interval between the data are too small;</p><p>CI is confidence interval</p><p>Enzymatic parameters from purified G6PD from study subjects in western Sumba according to genotype.</p

Scatter plot showing the relationship between age and G6PD activity in Sumba.

<p>Scatter plot showing the relationship between age and G6PD activity in Sumba.</p