The Absence of Sporozoites in Anopheles Mosquitoes in the Malaria Pre-elimination Area

Abstract

Introduction: The existence of sporozoites in the salivary gland of Anopheles is a prominent factor in the transmission and spread of malaria. Malaria control programs must be comprehensive including the treatment of patients, management of the vector population, and efforts to prevent human-vector contact. The present study aimed to track the presence of sporozoite in the Anopheles mosquito population in a malaria pre-elimination area and evaluate the implementation of a malaria elimination program. Methods: This cross-sectional study was conducted in a malaria pre-elimination area over a period of one year. Mosquitos were caught using human bait and in resting sites close to cattle pens. Sporozoites were detected microscopically and circumsporozoite protein (CSP) was tested using polymerase chain reaction technique. Results: A total of 212 Anopheles mosquitoes were caught. Anopheles maculatus, Anopheles aconitus, Anopheles subpictus, Anopheles barbirostris, Anopheles vagus, and Anopheles kochi species were identified. Salivary gland of 111 mosquitoes were dissected and CSP was detected in 101 specimens. Neither type of test found any sporozoites in the captured Anopheles. Conclusion: The absence of sporozoites in Anopheles in the pre-elimination area is a good sign of the ongoing malaria control program. Breaking the life cycle of the parasite that causes it by minimizing contact with vectors is an effective method that should be continuously improved.