Molecular detection of nosema apis and N. ceranae from southwestern and South Central USA Feral africanized and european honey bees, apis mellifera (Hymenoptera: Apidae)

Abstract

A Polymerase Chain Reaction (PCR) molecular diagnostic survey for the honey bee pathogens Nosema apis Zander and N. ceranae Fries was conducted on feral Africanized honey bee (AHB) and European honey bee (EHB), Apis mellifera L., populations sampled from Mississippi, Arkansas, Texas, Utah, Oklahoma, and New Mexico. Polymerase Chain Reaction - Restriction Fragment Length polymorphism (PCR-RFLP) analysis of a 220 bp small subunit (SSU) marker was conducted on 517 samples, consisting of 245 AHB and 272 EHB individuals. A total of 43 samples (8.3%) were positive for Nosema; of these, 82.1% were N. ceranae, and the remainder were N. apis. No mixed samples were observed. For the AHB samples, Nosema was detected in 9.0% of the samples with 89.5% of the Nosema identified as N. ceranae, and 10.5% as N. apis. With the EHB samples, 7.7% had Nosema; 75.0% of these with N. ceranae, and 25.0% with N. apis. No significant difference was observed between AHB and EHB feral samples for occurrence of each Nosema species and prevalence of Nosema infection. Among the AHB samples, Nosema was more common in Utah and Texas than in New Mexico and Oklahoma. Nosema infection rates for feral honey bees was considerably lower than levels observed with managed honey bees in studies from New York, South Dakota, and Virginia.