Avian leukosis virus subtype A and subtype J in different flocks with tumor disease

Virus de leucosis aviar subtipo A y subtipo J en diferentes bandadas con enfermedades tumorales

Dear Editor:

Avian leukosis virus (ALV) is the causal agent of the most common naturally occurring avian retroviral infections causing neoplastic disease and other production problems in chickens. There are six well-characterized chicken subgroups of ALV (A to E and J). Viruses of subgroups A, B and J occur as common pathogenic exogenous viruses in the field. ALV infections with subgroups A (ALV-A) and subgroups B (ALV-B) have had a significant impact in the commercial layer flocks, both are associated with lymphoid leukosis (B-cell lymphoma) producing mortality after sexual maturity and lowered egg production. Subgroups J (ALV-J) is associated with myeloid leukosis and other production problems in meat-type chickens.

Two different chicken flocks with tumor illness outbreaks, designated L and R, from local commercial breeding were sampled for ALV diagnosis. The main symptoms in the flocks L included weight loss, anemia and high mortality. The necropsy showed grayish-white nodules of different sizes commonly observed on liver, intestine and oviducts. In the flocks R, the main lesion was a tumor development in liver, spleen, kidney and the intestinal tract, including hemangiomas. ]]> DNA extracted from liver, spleen and tumors of both flocks were used to screen avian leucosis virus by PCR. Samples from flocks L gave an ALV-A specific 694-base pair product using H5 and capA primers. However, the samples from flocks R were positive to ALV-J specific 545-base pair product using H5 and H7 primers.

The circulation of avian leukosis virus subgroups A and J in our poultry suggests the necessity to study the epidemiological situation of ALV in our country.

D. Relova^I, A. Vega^I, A. Merino^II, D. Chong^I, C.L. Pereira^I, L.J. Pérez^I

^IAnimal Virology Laboratory. National Center for Animal and Plant Health (CENSA), CP 32700, Apdo. 10, San José de Las Lajas, Mayabeque, Cuba. E-mail: drelova@censa.edu.cu.
^IIAvian Diagnostic Laboratory (LIDA). Mulgoba. Santiago de las Vegas. La Habana, Cuba.

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