Genetic diversity of plasmodium vivax merozoite surface protein 3α and β field isolates

Abstract

Plasmodium parasites are the causative agents of a life-threatening malaria disease, causing a substantial economic loss to the health sectors on a global scale, especially in Pakistan, due to the presence of Plasmodium vivax and Plasmodium falciparum. However, P. vivax is highly prevalent and responsible for approximately 75% malaria infection with limited reports on its genetic diversity. The current study analyzed the genetic diversity of the P. vivax merozoite surface protein 3α and 3β (Pvmsp-3α and β) gene in field isolates of Azad Jammu and Kashmir (AJK) from Pakistan. Blood samples (n = 207) were collected from malaria-suspected patients in health care sectors between March and August 2024 for microscopy and DNA extraction. A nested PCR was performed targeting the Pvmsp-3α and Pvmsp-3β genes, followed by restriction fragment length polymorphism (RFLP) using AluI and PstI restriction enzymes. All microscopically examined samples were positive (207). Among them, PCR assay detected P. vivax in 188/207 (90.82%) samples and P. falciparum in 19/207 (9.18%) samples. Of the PCR-confirmed P. vivax samples, 98/188 (52.13%) and 90/188 (47.87%) were Pvmsp-3α and Pvmsp-3β amplified fragments, showing three and two major allelic variants, respectively. In Pvmsp-3α, the allelic distribution was type A (65/98, 66.33%), type B (11/98, 11.22%), and type C (13/98, 13.27%). Similarly, the allelic frequencies of Pvmsp-3β for type A and B were 69/90 (76.67%) and 21/90 (23.33%), respectively. This exploration of the P. vivax genotypic diversity from AJK is a major contribution to the demonstration of its complexity and polymorphism. The outcomes of the present findings are helpful in understanding the molecular epidemiology of P. vivax and exploring mixed genotype infection for control strategies.