ARTICLE Utilization of loop-mediated isothermal amplification (LAMP) technology for detecting White Spot Syndrome Virus (WSSV) and Vibrio spp. in Litopenaeus vannamei in selected sites in the Philippines Amalea Dulcene D. Nicolasora 1 , Benedict A. Maralit 4 , Christopher Marlowe A. Caipang 3 , Mudjekeewis D. Santos 4 , Adelaida Calpe 5 , and Mary Beth B. Maningas* 1,2 1 Research Center for the Natural and Applied Sciences, Thomas Aquinas Research Complex 2 Biological Sciences Department, College of Science, University of Santo Tomas, Philippines 1008 3 School of Applied Science, Temasek Polytechnic, Singapore 4 Genetic Fingerprinting Laboratory, National Fisheries Research and Development Institute, 101 Mother Ignacia St. Quezon City 1103 Philippines 5 Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development - Department of Science and Technology, Los Banos, Laguna S hrimp disease outbreaks in the Philippines remain to be uncontrollable. This is compounded by the inac- cessibility of disease diagnostics to most shrimp farmers. The loop-mediated isothermal amplification (LAMP) is a new technology that is used as a practi- cal alternative for rapid detection of viral and bacterial patho- gens. The method proves to be rapid, highly sensitive, and cost- effective compared to other detection assays. In this study, LAMP protocols for the detection of the two most common shrimp pathogens, white spot syndrome virus (WSSV) and Vi- brio spp., in the Philippines were developed. A temperature range of 55⁰C to 68⁰C for WSSV detection and 59⁰C to 67⁰C for Vibrio spp., and incubation periods of 45 minutes to 1 hour, were proven to be the suitable conditions for the LAMP assay. Using 309 Vol. 7 | No. 2 | 2014 Philippine Science Letters *Corresponding author Email Address: marybethmaningas@yahoo.com Submitted: August 12, 2013 Revised: June 30, 2014 Accepted: July 4, 2014 Published: September 10, 2014 Editor-in-charge: Eduardo A. Padlan these conditions, asymptomatic Litopenaeus vannamei samples from selected sites (Iloilo, Batangas, Bulacan, Laoag, and Leyte) were tested for WSSV. Samples which indicated WSSV infec- tion were from Iloilo (89.47%), Batangas (30.00%), Bulacan (43.33%), and Leyte (75.00%), while shrimps from Laoag City (0.00%) tested negative. Likewise, the occurrence of Vibrio spp. was determined in shrimps sampled in Pangasinan and six bacte- rial DNA isolates of Vibrio spp. were identified. Moreover, con- ventional PCR and microbiological methods were performed along with the LAMP reaction for comparison and further con- firmation. The results showed that the LAMP assay was faster and 10 times more sensitive than polymerase chain reaction in detecting WSSV and was more efficient than the traditional microbiological method in diagnosing vibriosis. Overall, the results indicated that a LAMP protocol, which is more conven- ient, highly sensitive, faster, and more practical, has been effec- tively utilized to detect WSSV and vibriosis in selected Philip- pine shrimp farms. KEYWORDS loop-mediated isothermal amplification, polymerase chain reac- tion, white spot syndrome virus, Vibrio spp., shrimps