Severe Plasmodium vivax Malaria in Pakistan

Ali Bin Sarwar Zubairi, Sobia Nizami, Afsheen Raza, Vikram Mehraj, Anita Fazal Rasheed, Najia Karim Ghanchi, Zahra Nur Khaled, and M. Asim Beg

Author affiliations: Aga Khan University, Karachi, Pakistan (A.B.S. Zubairi, S. Nizami, A. Raza, A.F. Rasheed, N.K. Ghanchi, Z.N. Khaled, M.A. Beg); Aix Marseille Université, Marseille, France (V. Mehraj)

Abstract

To compare the severity of Plasmodium vivax malaria with that of P. falciparum malaria, we conducted a retrospective cross-sectional study of 356 adults hospitalized with malaria (2009–2011) in Pakistan. P. vivax and P. falciparum accounted for 83% and 13% of cases, respectively; 79.9% of patients with severe malaria were infected with P. vivax.

Malaria is endemic to Pakistan and 64% and 36% of malaria cases are attributed to Plasmodium vivax and P. falciparum, respectively (1). The purpose of this study was to identify the complications of P. vivax among hospitalized malaria patients and compare the prevalence of these complications with those of P. falciparum malaria.

The Study

We conducted a retrospective cross-sectional study using convenience sampling at the Aga Khan University Hospital in Karachi, Pakistan. Participants were all adult patients (> 16 years of age) who were hospitalized with malaria during January 2009–December 2011. Reasons for hospitalization included intravenous antimalarial therapy, management of associated diagnoses, and complications. The following data on patients were retrieved through the hospital’s electronic and file records: age, sex, infecting Plasmodium species, malaria diagnosis methods, co-existing conditions, results of biochemical and microbiological investigations, radiographic findings, complications, hospital course, and outcome.
Records showed that Giemsa-stained peripheral blood smears, the malaria rapid diagnostic test (RDT), or both, were used for malaria diagnosis. The RDT used antibodies against P. falciparum histidine-rich protein 2 and P. vivax lactate dehydrogenase. For 45 case-patients for which results from peripheral blood smears and RDTs were discordant or unreliable, surface protein-specific PCR was performed by using stored patient blood samples to identify the Plasmodium species (2,3). Clinical syndromes were classified as severe on the basis of the World Health Organization’s 2010 severe falciparum malaria criteria (4).
Statistical analysis was performed by using SPSS version 20 (http://www-01.ibm.com/software/analytics/spss/

). Averages, χ² test of independence, odds ratios with 95% CIs, and analysis of variance were computed when applicable.
Case-patients with prior co-morbid conditions were excluded from relevant subanalyses, for example, diabetes mellitus patients were excluded from hypoglycemia analysis. All analysis was also repeated after excluding all case-patients with associated infections and comorbid illnesses. The classification “comorbidity” included all conditions in the Charlson comorbidity index for mortality (5). The study was approved by the Aga Khan University’s Ethics Review Committee.