Utilization of the polymerase chain reaction in the diagnosis of nuclear polyhedrosis virus infections of gypsy moth (Lymantria dispar, Lep., Lymantriidae) populations

Abstract

Three specific DNA probes were used for the detection of the nuclear polyhedrosis (NPV) virus of Lymantria dispar (LdNPV) genome. Two of these probes, H2 and H3 were obtained by classical cloning method and one (TR6) by polymerase chain reaction (PCR). These probes, used individually or in a pool in the standard slot–blot hybridizations, were able to detect 109 genome copies. By performing 35 cycles of PCR amplification before hybridization with primers specific to LdNPV genome on DNA extracted from infected larvae, the sensitivity of the hybridization technique was increased, so that as little as 10 copies of the LdNPV genome could be detected. Using these methods, L. dispar naturally infected by LdNPV were identified among field populations in Canada and in the United States near the eastern Canadian border. Using a combination of PCR and hybridization, LdNPV contamination of egg masses were also detected. By disinfecting the eggs with sodium hypochlorite prior to PCR amplification and hybridization, it was also demonstrated that transmission of viral infection in the natural populations is mainly caused by external contamination of the egg and is unlikely to occur through the transovarial route.

Transovum Transmission of Trypanosomatid Cysts in the Milkweed Bug, Oncopeltus fasciatus

“…This is particularly true for monoxenous trypanosomatids, which are still poorly understood [54] . Transovum transmission is a strategy shown by different parasites, supposedly with low cost to the host fitness [22] , [55] , [56] . Even though vertical transmission has been speculated [27] , [35] , trypanosomatids have only been described as horizontally transmitted by insects.…”

Transmission as a predictor of ecological host specificity with a focus on vertical transmission of microsporidia

“…Transovum transmission appears to be common for insect viruses, including the Lymantria dispar nuclear polyhedrosis virus (NPV) for which only chorion contamination was demonstrated (no transovarial transmission) (Charpentier et al, 2003); but for most of the viruses evaluated, and for the microsporidia, spores or developmental forms usually occur within the egg or both within and on the chorion. Transovum transmission may also involve venereal transmission of the pathogen from infected male to female host and, thus, to the oVspring via ingestion of the contaminated egg chorion upon hatching.…”