Simultaneous endemic infections with subgroup J avian leukosis virus and reticuloendotheliosis virus in commercial and local breeds of chickens

Abstract

Epidemiological studies of subgroup J avian leukosis virus (ALV-J) and reticuloendotheliosis virus (REV) infections were conducted during 1999 to 2009 on 29 chicken flocks of various commercial and local breeds located in six provinces in China. Samples were typically from chickens with myelocytomas or proventricular lesions. ALV-J was isolated from 25 flocks including seven out of seven flocks containing ''yellow chickens'' or other local breeds and several flocks of layer chickens. REV was isolated from 19 flocks. Co-infection of ALV-J and REV was confirmed in 11/38 birds of 8/15 flocks with myelocytomatosis and in 11/24 birds of 3/5 flocks with proventricular lesions. Both ALV-J and REV were vertically transmitted in four breeder flocks of local chicken breeds. One experiment in specific pathogen free chickens indicated that co-infection at hatch strongly depressed antibody responses to ALV-J but not to REV. The results suggest that infections with both ALV-J and REV have become endemic in local breeds, including breeder flocks where both viruses appear to be perpetuated by vertical transmission. In addition, both viruses were present in at least some commercial broiler, layer and breeder flocks. Eradication programmes are needed but will be difficult, especially in local breeds. This unprecedented concurrence of simultaneous endemic infections with ALV-J and REV may have serious economic consequences and needs to be better understood.

Development and Application of a Multiplex PCR Method for Rapid Differential Detection of Subgroup A, B, and J Avian Leukosis Viruses

“…One positive sample with coinfection with ALV-A and ALV-B and 2 positive samples with coinfections with ALV-A and ALV-J were found in clinical samples in the present study. Coinfection, which may have a more powerful pathogenicity and which brings about more serious economic losses, has become widespread among flocks in China (40). Furthermore, coinfection with different subgroups provides the opportunity for the recombination of ALVs and makes it possible for the emergence of new subgroup viruses, such as ALV-J, with stronger pathogenicity and epidemicity (8,31).…”

Naturally Occurring Co-infection of Avian Leukosis Virus (subgroups A-E) and Reticuloendotheliosis Virus in Green Peafowls (Pavo muticus)

“…Zheng et al (2006) observed that an increase in the incidence of MD in broilers was associated with a simultaneous increase in the incidence of REV in chickens. Some researchers recently reported simultaneous endemic infections with ALV subgroup J and REV in commercial and local breeds of chickens in China (Cui et al, 2009).Another recent study also demonstrated the synergic pathological effects of the co-infection of CAV-MG (Mycoplasma gallisepticum) vaccine strains on experimentally-infected young SPF broiler chickens (Prezotto et al, 2016) based on pathology and molecular methods, like the present study. In the present study, it was not clear which virus first infected the birds.…”

Identification of avian leukosis virus subgroup J-associated acutely transforming viruses carrying the v-src oncogene in layer chickens

“…The helper virus strain SDAU1102 was isolated from cultures exposed to viral stocks diluted beyond the end point of transformed focus formation. CEFs were prepared from 11-day-old chicken embryos, according to classical methods, and cultured in Dulbecco's modified Eagle's medium supplemented with 5 % newborn calf serum, as described previously (Cui et al, 2009). …”