Lesson 11 ASFARVIRIDAE

Question 1

Lesson 11: Asfarviridae
General description:
 Formerly assigned to the family
________
 ____ DNA virus
 ______ symmetry

Answer 1

Iridoviridae
Enveloped
Icosahedral

Question 2

Replicates in cytoplasm of host cells and
in soft ticks of the Ornithodorus species

Answer 2

Asfarviridae

Question 3

Causes African swine fever

Answer 3

Asfarviridae

Question 4

ASFARVIRIDAE
 Replication occurs in the ____ of
host cells with release by budding through
the plasma membrane or by
cell destruction
 African swine fever virus is stable in the
environment at 20°C or 4°C and over a
wide pH range, permitting the virus to
persist for weeks or months in meat.

Answer 4

cytoplasm

Question 5

ASFARVIRIDAE

The African swine fever virus is an
unusual complex DNA virus and is not
related to other viruses. This has
presented challenges for vaccine
development, Vaccine is now
available.
 Infectivity is destroyed by heating, lipid
solvents and certain disinfectants such as
the paraphenylphenolic disinfectant

Question 6

African Swine Fever (ASF) Virus infection
 An economically important viral haemorrhagic disease of pigs characterized by
fever, haemorrhages in the _________________ and a high mortality rate
 The virus was first detected in _____________________ although the
first outbreak was recorded in ________
 Symptoms of the infection include appetite loss, redness of the skin, vomiting
and diarrhea
 Controlling and preventing the infection is highly prioritized as the transmission is
quick, but the disease is hard to detect, and it may take days before the
symptoms show
 The spread of the ASF jumped from Africa to Europe through the exportation of
contaminated meat.

Answer 6

*reticuloendothelial system
*Sub-Saharan Africa in the 1920s, and Portugal in 1957
*

Question 7

The first ASF outbreak in the Philippines occurred in a backyard farm in Rizal
province on ____.

Answer 7

July 25, 2019

Question 8

ASF On ________, ASF virus was detected in cured pork items of an
unidentified brand including breakfast staples hotdog, tocino, and longganisa.

Answer 8

October 24, 2019

Question 9

In Eastern Visayas, the first case of ASF was recorded in Abuyog, Leyte on
__________. After 2 months, Northern Samar reported its first ASF outbreak in
the town of Lope de vega.

Answer 9

January 2021

Question 10

Epidemiology: of ASFARVIRIDAE

Answer 10

Domestic and wild pigs are the only species susceptible to
infection. In Africa, ASFV is maintained in a sylvatic cycle involving soft ticks of
the genus Ornithodorus and inapparent infection of warthogs and bushpigs (Fig.
9)
 As ticks are able to maintain and transmit the virus to pigs for years, the
presence of ticks in a particular region makes the eradication of ASF difficult.
The principal tick species involved in transmission are O. porcinus porcinus (O.
moubata) in Africa and O. erraticus in Spain and Portugal.
 Following infection of domestic pigs with virulent virus, body fluids and tissues
contain large quantities of virus until death or recovery occurs.
 Ingestion of uncooked meat from infected pigs is a major method of transmission.
 Spread can also occur by direct contact(oral or nasal secretions) or indirect
transmission can occur through contaminated transport vehicles, fomites and
footwear.
 Feeding uncooked swill is an important mechanism of spread of ASF
internationally, with outbreaks often starting in herds close to airports and ports.
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*Pigs which have recovered from clinical disease may remain infected for long
period and serve as carrier pigs which is considered to be an important
mechanism of viral dissemination.

Question 11

The maintenance and transmission of African swine fever virus in wild and
domestic pig populations and in tick vectors.

Question 12

Pathogenesis and Pathology of Asfarviridae

Answer 12

 The incubation period varies from four to 19 days but is typically five
to seven days in acute cases.
 Infection in domestic pigs is usually acquired via the oronasal route.
 The virus replicates initially in the pharyngeal mucous membrane
and tonsils before spreading to the draining lymph nodes. Infection
then extends via the bloodstream to the target organs which include
lymph nodes, bone marrow, spleen, lung, liver and kidney. These are
the main sites of secondary replication, which gives rise to a
prolonged viraemia.
 The virus replicates primarily in the cells of the lymphoreticular
system, particularly cells of the mononuclear phagocyte system, but
also infects megakaryocytes, endothelial cells, kidney cells and
hepatocytes.
 Lesions are widespread in the body and include splenic enlargement,
swollen and haemorrhagic gastrohepatic and renal lymph nodes,subcapsular petechiae in the kidneys, petechial and ecchymotic
haemorrhages in the heart walls and serosal surfaces,oedema of
the lungs, hydrothorax and haemorrhages of the pleura.
 The pathogenesis of the haemorrhages appears to be largely related
to the development of disseminated intravascular coagulation and
the destruction of megakaryocytes
 In chronic cases of ASF,lesions are largely confined to the
respiratory tract and include pneumonia, fibrinous pleuritis and
pericarditis, pleural adhesions and hyperplasia of lymphoreticular
tissues.

Question 13

Diagnosis of ASF or Asfarviridae

Answer 13

 Laboratory confirmation (RT-PCR, ELISA) of ASFV is required on
account of the similarity of the clinical signs and lesions to a number
of other pig diseases such as classical swine fever, erysipelas and
septicaemic salmonellosis.
 Suitable samples include blood, serum, tonsil, spleen, kidney and
lymph nodes