# The Association Between Malaria Parasite Geometrical Mean and Clinical Spectrum of Severe Disease in a High-Transmission Setting in Eastern Uganda: A Cross-Sectional Study

## TL;DR

This study finds that in a high-malaria area of Uganda, the number of parasites in the blood does not reliably predict how severe a child's malaria is.

## Contribution

The study provides new evidence that parasite geometrical mean is not a reliable indicator of malaria severity in high-transmission regions.

## Key findings

- Severe malaria cases in Eastern Uganda had parasite geometrical means similar to uncomplicated cases.
- The highest parasite geometrical mean was observed in patients with shock, while the lowest was in those with severe anemia.
- Inpatient mortality rate was 3.4% among children with severe malaria.

## Abstract

Background: Malaria burden remains significant, especially in high-transmission settings. While some data show an association between severe malaria and high-malaria parasite geometrical mean (GM), few data describe this phenomenon in malaria high-transmission settings. We described the malaria parasite GM and clinical spectrum of severe malaria in Eastern Uganda to advance understanding of its implications on disease severity and patient outcomes.

Methods: We conducted a cross-sectional study in Mbale Regional Referral Hospital (MRRH), Eastern Uganda. Children admitted with severe malaria confirmed by microscopy with ages between 2 months and 12 years were enrolled in the study from September 21, 2021, to September 21, 2022. Data were collected on patient sociodemographics, clinical symptoms and signs, laboratory parameters, treatment details, and outcomes. From the blood samples collected at the bedside, blood films/smears were made. The malaria parasite count was obtained from the patients' smears by counting the malaria parasites against 200 white blood cells (WBCs). The GMs of malaria were obtained after the logarithmic transformation of the parasite counts. Data were analyzed using Stata 15, and significant associations were reported at p values of 0.05 at 95% confidence intervals.

Results: A total of 376 children with a mean age of 4.65 years were recruited, of whom 57.71% (217/376) were male. Children under 5 years constituted 61.7% (232/376). The common clinical manifestations were prostration 76.9% (289/376), jaundice 55.6% (209/376), severe anemia 48.4% (182/377), and hemoglobinuria 46.5% (175/376). The overall malaria parasite GM was 12,238.42 parasites/microliter (95% CI: 9166.72–16,339.43). The highest GM of 197,000 parasites/microliter (95% CI: 40,817.64–946,368) and the lowest of 8938.185 parasites/microliter (95% CI: 5932.8–13,466.01) were observed in shock and severe anemia, respectively. Inpatient mortality was 3.4%.

Conclusion: In malaria high-transmission settings of Eastern Uganda, patients with severe malaria had low parasite GMs similar to those in uncomplicated malaria. Thus, malaria parasite GM should not be relied upon to determine disease severity in these settings.