Optimization of Plasmodium vivax sporozoite production from Anopheles stephensi in South West India

• Published in: Malaria Journal
• Main Authors: Ajeet Kumar Mohanty, Charles de Souza, Deepika Harjai, Prathamesh Ghavanalkar, Mezia Fernandes, Anvily Almeida, Jayashri Walke, Suresh Kumar Manoharan, Ligia Pereira, Rashmi Dash, Anjali Mascarenhas, Edwin Gomes, Thanyapit Thita, Laura Chery, Anupkumar R. Anvikar, Ashwani Kumar, Neena Valecha, Pradipsinh K. Rathod, Rapatbhorn Patrapuvich
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2021
• Subjects: Anopheles stephensi; Insectary; Plasmodium vivax; Membrane-feeding assays; Sporozoite; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-021-03767-2; https://doaj.org/article/5b287c73790f4137ad885d1e8efec12a

Abstract Background Efforts to study the biology of Plasmodium vivax liver stages, particularly the latent hypnozoites, have been hampered by the limited availability of P. vivax sporozoites. Anopheles stephensi is a major urban malaria vector in Goa and elsewhere in South Asia. Using P. vivax patient blood samples, a series of standard membrane-feeding experiments were performed with An. stephensi under the US NIH International Center of Excellence for Malaria Research (ICEMR) for Malaria Evolution in South Asia (MESA). The goal was to understand the dynamics of parasite development in mosquitoes as well as the production of P. vivax sporozoites. To obtain a robust supply of P. vivax sporozoites, mosquito-rearing and mosquito membrane-feeding techniques were optimized, which are described here. Methods Membrane-feeding experiments were conducted using both wild and laboratory-colonized An. stephensi mosquitoes and patient-derived P. vivax collected at the Goa Medical College and Hospital. Parasite development to midgut oocysts and salivary gland sporozoites was assessed on days 7 and 14 post-feeding, respectively. The optimal conditions for mosquito rearing and feeding were evaluated to produce high-quality mosquitoes and to yield a high sporozoite rate, respectively. Results Laboratory-colonized mosquitoes could be starved for a shorter time before successful blood feeding compared with wild-caught mosquitoes. Optimizing the mosquito-rearing methods significantly increased mosquito survival. For mosquito feeding, replacing patient plasma with naïve serum increased sporozoite production > two-fold. With these changes, the sporozoite infection rate was high (> 85%) and resulted in an average of ~ 22,000 sporozoites per mosquito. Some mosquitoes reached up to 73,000 sporozoites. Sporozoite production could not be predicted from gametocyte density but could be predicted by measuring oocyst infection and oocyst load. Conclusions Optimized conditions for the production of high-quality P. vivax ...