Study of Genetic Diversity and Genetic Relationship of Mitochondrial Cytochrome c Oxidase Subunit 1 (cox1) Gene of Plasmodium knowlesi in Thailand

Abstract

Malaria affects 40% of people worldwide. Plasmodium knowlesi is found in Macaca fascicularis in Southeast Asian countries and can be transmitted to humans. Cytochrome c oxidase subunit 1 gene (cox1) is an important mitochondrial DNA encoding important protein subunits in the cellular respiratory process. Cox1 is commonly used to identify species and study the evolution of living beings. The objective of this research is to study of genetic diversity and genetic relationship of Mitochondrial cox1 gene of Plasmodium knowlesi in Thailand. In this research, forty DNA samples were collected from 11 provinces in Thailand and confirmed as P. knowlesi. Cox1 gene was used as the DNA target for amplification by PCR. The phylogenetic tree was constructed from nucleotides sequence data of cox1 gene to classify P. knowlesi cluster in Thailand by using the Maximum Parsimony method. The correlations between clusters and patient data, residential area, and parasite density were analyzed. The results showed that the phylogenetic tree can divide P. knowlesi into 13 clusters (Cluster I-XIII). Cluster I (8 isolates), Cluster II (7 isolates), Cluster III (3 isolates), Cluster IV (1 isolate), Cluster V (4 isolates), Cluster VI (1 isolate), Cluster VII (3 isolates), Cluster VIII (1 isolate), Cluster IX (1 isolate), Cluster X (3 isolates), Cluster XI (2 isolates), Cluster XII (1 isolate), and Cluster XIII (5 isolates). There were more males infected with P. knowlesi (35 males) than females (5 females). The age group infected with P. knowlesi < 40 years old was 15 persons and age group ≥ 40 years old was 25 persons. Thirty-nine persons are Thai and 1 person is Myanmar. Twenty-six patients from 33 patients have parasite density < 10,000 /μL of blood and 7 patients have parasite density ≥ 10,000 /μL of blood. In conclusion, P. knowlesi were divided into 13 clusters. The parasites in the same clusters are similar in genetics and most isolates in different areas have different nucleotide sequences. This research is preliminary data of molecular epidemiology of P. knowlesi in Thailand. This data can be applied in public health and planning for malaria control and malaria eradication in Thailand.