virus

ARTÍCULO GENERAL
Circovirus Porcino: Un virus pequeño que genera
un gran problema
Porcine Circovirus: A small virus that causes a great problem

Jorge Noriega1, Paulina R eyes1, Sergio Bucarey1

Abstract
Porcine circoviruses type 1 and type 2 (PCV-1 and PCV-2) are very small (17 nm), nonenveloped,
icosahedral viruses (Tisher y col., 1982), with circular, single stranded DNA genomes ofapproximately
1,700 nucleotides length, encoding 2 major ambisense open reading frames (Mankertz y col., 1998;
Hamel y col., 1998). Together with a number of avian viruses with similar molecular characteristics,
the porcine circoviruses are classified in the genus Circovirus within the family Circoviridae. Although
PCV-1 persists in the pig population, the presence of PCV-1 has not beenassociated with any recognised
clinical signs or pathology. In contrast, PCV-2 has been implicated as the mayor causative agent of
Postweaning Multisystemic Wasting Syndrome (PMWS). It is characterized mainly by loose of weight,
general wasting, and severe immunosuppressive effects with premature death of piglets.
PCV-2 effects are generated by inhibition of plasmacytoid dendritic cells (pdc) socalled natural
interferon-α producing cells (NIPCs) unlinking the innate and acquired immune systems, and rendering
a host susceptible to secondary or concomitant microbial infections. Therefore, PCV-2 additionally is
associated with other porcine diseases and syndromes, such as reproductive failure, respiratory disease
complex, congenital tremor, porcine dermatitis and nephropathy syndrome,nectrotizing tracheitis and
exudative epidermitis, together with other viral and bacterial agents, including Parvovirus, PRRSV
(Porcine Reproductive and Respiratory Syndrome virus), Influenza, Aujeszky and Mycoplasma pneumoniae,
Actinobacillus pleuropneumoniae, Streptococcus suis and Pastereulla multocida. Nowadays, these
diseases are known as PCVAD or PCV-2-associated diseases, in order to groupall the diseases attributed
to porcine circovirus type 2.
The PCV-2-associated diseases, mainly PMWS, at present are considered to be the greatest economic
problem associated with the pig industry world-wide.
Key words:  PCV-2, circovirus, wasting diseases, PCVAD.

R esumen
Los circovirus porcinos tipo 1 y tipo 2 (PCV-1 y PCV-2) son virus muy pequeños (17 nm), no envueltos,
de simetríaicosahédrica (Tisher y col., 1982), con un DNA circular de hebra simple de aproximadamente
1.700 nucleótidos de longitud, el cual codifica principalmente dos marcos de lectura abiertos (Mankertz
y col., 1998; Hamel y col., 1998). En conjunto con un número de virus aviares con características
moleculares similares, los circovirus porcinos se clasifican en el género Circovirus dentro de la familiaCircoviridae. Aunque el PCV-1 es persistente en la población de cerdos, la presencia de PCV-1 no ha sido
asociada con ninguna signología clínica o patología reconocida. En contraste, PCV-2 ha sido implicado
como el agente etiológico principal del Síndrome Multisistémico de Desmedro Postdestete (PMWS),
caracterizado principalmente por pérdida de peso, deterioro general de la condición corpórea yefectos
inmunosupresivos severos, los que conllevan a la muerte prematura de los lechones.

1

Centro Biotecnológico Veterinario Biovetec y Departamento de Ciencias Biológicas Animales, Facultad de Ciencias
Veterinarias y Pecuarias, Universidad de Chile.

Avances en Ciencias Veterinarias 22, pp. 62-71, 2007

Circovirus porcino: un virus pequeño que genera un gran problema

63

Losefectos de PCV-2 son generados por inhibición de las células dendríticas plasmocitoideas (pDC),
también llamadas células productoras naturales de interferon-α (NIPCs), afectando al sistema inmune innato
y adquirido, y dejando al hospedero susceptible a infecciones microbianas secundarias o concomitantes.
De esta manera, PCV-2 adicionalmente se asocia a otras enfermedades y síndromes porcinos,...